From 583a1ce5d1b225a6b01fc2b30a3bcb21fd0d48c9 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 11 May 2002 13:00:22 -0400 Subject: [PATCH] Check in ext2ed version 0.1 --- ext2ed/COPYRIGHT | 346 +++++ ext2ed/Makefile | 78 + ext2ed/README | 101 ++ ext2ed/blockbitmap_com.c | 265 ++++ ext2ed/dir_com.c | 675 +++++++++ ext2ed/disk.c | 238 +++ ext2ed/doc/Ext2fs-overview-0.1.sgml | 898 ++++++++++++ ext2ed/doc/ext2ed-design-0.1.sgml | 2102 +++++++++++++++++++++++++++ ext2ed/doc/ext2ed.8 | 72 + ext2ed/doc/user-guide-0.1.sgml | 1189 +++++++++++++++ ext2ed/ext2.descriptors | 407 ++++++ ext2ed/ext2_com.c | 97 ++ ext2ed/ext2ed.conf | 79 + ext2ed/ext2ed.h | 438 ++++++ ext2ed/file_com.c | 564 +++++++ ext2ed/general_com.c | 748 ++++++++++ ext2ed/group_com.c | 182 +++ ext2ed/init.c | 607 ++++++++ ext2ed/inode_com.c | 436 ++++++ ext2ed/inodebitmap_com.c | 214 +++ ext2ed/main.c | 374 +++++ ext2ed/super_com.c | 159 ++ ext2ed/win.c | 169 +++ 23 files changed, 10438 insertions(+) create mode 100644 ext2ed/COPYRIGHT create mode 100644 ext2ed/Makefile create mode 100644 ext2ed/README create mode 100644 ext2ed/blockbitmap_com.c create mode 100644 ext2ed/dir_com.c create mode 100644 ext2ed/disk.c create mode 100644 ext2ed/doc/Ext2fs-overview-0.1.sgml create mode 100644 ext2ed/doc/ext2ed-design-0.1.sgml create mode 100644 ext2ed/doc/ext2ed.8 create mode 100644 ext2ed/doc/user-guide-0.1.sgml create mode 100644 ext2ed/ext2.descriptors create mode 100644 ext2ed/ext2_com.c create mode 100644 ext2ed/ext2ed.conf create mode 100644 ext2ed/ext2ed.h create mode 100644 ext2ed/file_com.c create mode 100644 ext2ed/general_com.c create mode 100644 ext2ed/group_com.c create mode 100644 ext2ed/init.c create mode 100644 ext2ed/inode_com.c create mode 100644 ext2ed/inodebitmap_com.c create mode 100644 ext2ed/main.c create mode 100644 ext2ed/super_com.c create mode 100644 ext2ed/win.c diff --git a/ext2ed/COPYRIGHT b/ext2ed/COPYRIGHT new file mode 100644 index 00000000..5585eb6e --- /dev/null +++ b/ext2ed/COPYRIGHT @@ -0,0 +1,346 @@ +EXT2ED is hereby placed under the terms of the GNU General Public License. +Follows the GNU license. + +Gadi Oxman, August 1995 + +--------------------------------------------------------------------------- + + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 675 Mass Ave, Cambridge, MA 02139, USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software--to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Library General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + + GNU GENERAL PUBLIC LICENSE + TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION + + 0. This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The "Program", below, +refers to any such program or work, and a "work based on the Program" +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term "modification".) Each licensee is addressed as "you". + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + + 1. You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + + 2. You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + + a) You must cause the modified files to carry prominent notices + stating that you changed the files and the date of any change. + + b) You must cause any work that you distribute or publish, that in + whole or in part contains or is derived from the Program or any + part thereof, to be licensed as a whole at no charge to all third + parties under the terms of this License. + + c) If the modified program normally reads commands interactively + when run, you must cause it, when started running for such + interactive use in the most ordinary way, to print or display an + announcement including an appropriate copyright notice and a + notice that there is no warranty (or else, saying that you provide + a warranty) and that users may redistribute the program under + these conditions, and telling the user how to view a copy of this + License. (Exception: if the Program itself is interactive but + does not normally print such an announcement, your work based on + the Program is not required to print an announcement.) + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + + 3. You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + + a) Accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of Sections + 1 and 2 above on a medium customarily used for software interchange; or, + + b) Accompany it with a written offer, valid for at least three + years, to give any third party, for a charge no more than your + cost of physically performing source distribution, a complete + machine-readable copy of the corresponding source code, to be + distributed under the terms of Sections 1 and 2 above on a medium + customarily used for software interchange; or, + + c) Accompany it with the information you received as to the offer + to distribute corresponding source code. (This alternative is + allowed only for noncommercial distribution and only if you + received the program in object code or executable form with such + an offer, in accord with Subsection b above.) + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + + 4. You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + + 5. You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + + 6. Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + + 7. If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + + 8. If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + + 9. The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and "any +later version", you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + + 10. If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + + NO WARRANTY + + 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + + 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. + + END OF TERMS AND CONDITIONS + + Appendix: How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) 19yy + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) 19yy name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/ext2ed/Makefile b/ext2ed/Makefile new file mode 100644 index 00000000..ec5a86f0 --- /dev/null +++ b/ext2ed/Makefile @@ -0,0 +1,78 @@ +# /gadi/project/Makefile +# +# Makefile for the extended-2 filesystem editor. +# +# First created : April 8 1995 +# +# Copyright (C) 1995 Gadi Oxman + +# ------------------------------------------------------------------------ +# EXT2ED, ncurses and readline +# ------------------------------------------------------------------------ +# +# EXT2ED requires the ncurses and readline libraries. +# +# Please define OLD_NCURSES below if you are using an old version of ncurses. +# I don't know the exact threshold, but from my experience this flag is needed +# for version 1.8.5 and not needed for 1.9.2c and up. In any case, you will +# notice immediately that this flag is wrong - The main window will be totally +# corrupted. + +# FLAGS = -DOLD_NCURSES + +# Define the directories below to insure that the compiler will find the +# required ncurses and readline include files / libraries. Be sure that you +# don't mix two two versions of ncurses. + +# NCURSES_INCLUDE = -I/usr/local/include -I/usr/local/include/ncurses +# NCURSES_LIB = -L/usr/local/lib +# READLINE_INCLUDE = -I/usr/include -I/usr/include/readline +# READLINE_LIB = -L/usr/lib + +# ------------------------------------------------------------------------ +# Install Directories +# ------------------------------------------------------------------------ + +# The executable will go into BIN_DIR. +# The configuration file, log file, etc will go into VAR_DIR. +# The manual page will go into MAN_DIR. +# The EXT2ED documentation will go into DOC_DIR. + +BIN_DIR = /usr/bin +VAR_DIR = /var/lib/ext2ed +MAN_DIR = /usr/man/man8 +DOC_DIR = /usr/doc/ext2ed + +# ------------------------------------------------------------------------ + +CC = gcc +CCFLAGS = -O $(FLAGS) -DVAR_DIR=\"$(VAR_DIR)\" $(NCURSES_INCLUDE) $(READLINE_INCLUDE) +LINKFLAGS = $(NCURSES_LIB) $(READLINE_LIB) +LIBS = -lreadline -lncurses + +.c.o: + $(CC) $(CCFLAGS) $(INCLUDE_DIR) -c $< + +OBJS= main.o init.o general_com.o inode_com.o dir_com.o super_com.o \ + disk.o win.o group_com.o file_com.o blockbitmap_com.o ext2_com.o \ + inodebitmap_com.o + +ext2ed: $(OBJS) + $(CC) $(OBJS) $(LINKFLAGS) $(LIBS) -o ext2ed + +clean: + rm ext2ed *.o + +install: ext2ed + install -d $(VAR_DIR) + install -d $(DOC_DIR) + install -m 755 ext2ed $(BIN_DIR) + install -m 644 ext2.descriptors $(VAR_DIR) + install -m 644 ext2ed.conf $(VAR_DIR) + install -m 644 doc/ext2ed.8 $(MAN_DIR) + install -m 644 doc/user-guide-0.1.sgml $(DOC_DIR) + install -m 644 doc/user-guide-0.1.ps $(DOC_DIR) + install -m 644 doc/Ext2fs-overview-0.1.sgml $(DOC_DIR) + install -m 644 doc/Ext2fs-overview-0.1.ps $(DOC_DIR) + install -m 644 doc/ext2ed-design-0.1.sgml $(DOC_DIR) + install -m 644 doc/ext2ed-design-0.1.ps $(DOC_DIR) diff --git a/ext2ed/README b/ext2ed/README new file mode 100644 index 00000000..7d187f2f --- /dev/null +++ b/ext2ed/README @@ -0,0 +1,101 @@ +ext2ed - The extended-2 filesystem editor, version 0.1 +------------------------------------------------------ + +This is version 0.1 of ext2ed - The extended-2 filesystem editor. + +Documentation +------------- + +ext2ed's documentation consists of three documents: + +1. The user's guide. +2. Technical overview of the ext2 filesystem. +3. The EXT2ED design and implementation document. + +Those documents are available in the doc directory, in linuxdoc-sgml and +postscript formats. + +The documentation is also available online at: + +http://tochnapc2.technion.ac.il + +under the ext2ed section. + +Installation +------------ + +ext2ed requires the kernel sources and the readline and ncurses packages. +Please edit the makefile if you are using an "old" version of ncurses (See the +details below) or if gcc can't find the various header files and libraries. + +To install, simply issue a 'make' command to compile and a 'make install' +command to install. I have also included an already compiled linux a.out +binary. + +ext2ed and ncurses +------------------ + +ext2ed uses the ncurses library for terminal output. It is very important +that ncurses will be properly installed on your system: + +1. Old versions of ncurses (around 1.8.5) need the OLD_NCURSES compile + time option in EXT2ED. + + At least from 1.9.2c, this flag should not be used. I would recommend + upgrading the ncurses library to the newer versions. + +2. ncurses uses its own terminfo database rather then the termcap file. + It is important that the terminfo database will be found by ncurses. + If this is not the case, you will see on startup some lines which + refer to /etc/termcap. This will mean that there is a problem with + the terminfo database. + +3. Newer versions of ncurses (and the 1.3 series of the kernel) describe + the linux console in the entry 'linux' and not 'console', as it was + before. If you run ext2ed in the linux console, you should either + set your TERM environment variable to 'linux' or link + l/linux to c/console in the terminfo database. + +4. The percompiled binary was linked with ncurses 1.9.4 and will search + for the terminfo database on /usr/local/lib/terminfo. If you are + using it, and your 1.9.4 compatible terminfo database is not on the + directory above, use the TERMINFO environment variable to specify + an alternate location. + +Running ext2ed +-------------- + +For those of you who don't like reading lengthy articles, here are a few +basic guidelines: + +1. Don't use ext2ed to change a mounted filesystem ! + + Using ext2ed in read-only mode on a mounted filesystem can be allowed + by using the configuration file option 'AllowMountedRead on'. However, + note that the displayed data will be unreliable. + +2. ext2ed currently can't handle filesystems bigger than 2 GB. I am + sorry for the inconvenience. This will hopefully be fixed in future + releases. + +3. Before running ext2ed, edit the configuration file + /var/lib/ext2ed/ext2ed.conf to suit your needs. The various + configuration options are documented there. + +4. Use the 'setdevice' command to open an ext2 filesystem. + e.g. 'setdevice /dev/hda1'. + +5. If the filesystem is an ext2 filesystem and ext2ed fails to + autodetect this, use the 'ForceExt2 on' configuration file option. + +6. The filesystem will always be opened in read-only mode. Feel free to + experiment, but take care with the 'enablewrite' command. + +----------------------------------------------------------------------------- + +Feel free to send me feedback with anything regarding to ext2ed. + +Enjoy, + +Gadi Oxman +Haifa, August 23 1995 \ No newline at end of file diff --git a/ext2ed/blockbitmap_com.c b/ext2ed/blockbitmap_com.c new file mode 100644 index 00000000..355feb03 --- /dev/null +++ b/ext2ed/blockbitmap_com.c @@ -0,0 +1,265 @@ +/* + +/usr/src/ext2ed/blockbitmap_com.c + +A part of the extended file system 2 disk editor. + +------------------------- +Handles the block bitmap. +------------------------- + +This file implements the commands which are specific to the blockbitmap type. + +First written on: July 5 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include +#include +#include + +#include "ext2ed.h" + +/* + +The functions in this file use the flobal structure block_bitmap_info. This structure contains the current +position in the bitmap. + +*/ + +void type_ext2_block_bitmap___entry (char *command_line) + +/* + +This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info +and dispatches a show command to show the new entry. + +*/ + +{ + unsigned long entry_num; + char *ptr,buffer [80]; + + + + ptr=parse_word (command_line,buffer); /* Get the requested entry */ + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n"); + refresh_command_win (); return; + } + ptr=parse_word (ptr,buffer); + + entry_num=atol (buffer); + + + if (entry_num >= file_system_info.super_block.s_blocks_per_group) { /* Check if it is a valid entry number */ + + wprintw (command_win,"Error - Entry number out of bounds\n"); + refresh_command_win ();return; + } + + + + block_bitmap_info.entry_num=entry_num; /* If it is, just change entry_num and */ + strcpy (buffer,"show");dispatch (buffer); /* dispatch a show command */ +} + +void type_ext2_block_bitmap___next (char *command_line) + +/* + +This function passes to the next entry in the bitmap. We just call the above entry command. + +*/ + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_block_bitmap___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_block_bitmap___allocate (char *command_line) + +/* + +This function starts allocating block from the current position. Allocating involves setting the correct bits +in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that +we need to allocate, and call allocate_block for each one. + +*/ + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); /* Get the number of blocks to allocate */ + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=block_bitmap_info.entry_num; + /* Check for limits */ + if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much blocks in the group\n"); + refresh_command_win ();return; + } + + while (num) { /* And call allocate_block */ + allocate_block (entry_num); /* for each block */ + num--;entry_num++; + } + + dispatch ("show"); /* Show the result */ +} + +void type_ext2_block_bitmap___deallocate (char *command_line) + +/* This is the opposite of the above function - We call deallocate_block instead of allocate_block */ + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=block_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_blocks_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much blocks in the group\n"); + refresh_command_win ();return; + } + + while (num) { + deallocate_block (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + + +void allocate_block (long entry_num) + +/* In this function we convert the bit number into the right byte and inner bit positions. */ + +{ + unsigned char bit_mask=1; + int byte_offset,j; + + byte_offset=entry_num/8; /* Find the correct byte - entry_num/8 */ + /* The position inside the byte is entry_num %8 */ + for (j=0;j0;i--) + j*=2; + if ((*ptr) & j) + wprintw (show_win,"Allocated\n"); + else + wprintw (show_win,"Free\n"); + refresh_show_win (); +} diff --git a/ext2ed/dir_com.c b/ext2ed/dir_com.c new file mode 100644 index 00000000..e1471fbc --- /dev/null +++ b/ext2ed/dir_com.c @@ -0,0 +1,675 @@ +/* + +/usr/src/ext2ed/dir_com.c + +A part of the extended file system 2 disk editor. + +-------------------- +Handles directories. +-------------------- + +This file contains the codes which allows the user to handle directories. + +Most of the functions use the global variable file_info (along with the special directory fields there) to save +information and pass it between them. + +Since a directory is just a big file which is composed of directory entries, you will find that +the functions here are a superset of those in the file_com.c source. + +We assume that the user reached here using the dir command of the inode type and not by using settype dir, so +that init_dir_info is indeed called to gather the required information. + +type_data is not changed ! It still contains the inode of the file - We handle the directory in our own +variables, so that settype ext2_inode will "go back" to the inode of this directory. + +First written on: April 28 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include +#include +#include + +#include "ext2ed.h" + +char name_search [80]; +long entry_num_search; + +int init_dir_info (struct struct_file_info *info_ptr) + +/* + +This function is called by the inode of the directory when the user issues the dir command from the inode. +It is used to gather information about the inode and to reset some variables which we need in order to handle +directories. + +*/ + +{ + struct ext2_inode *ptr; + + ptr=&type_data.u.t_ext2_inode; /* type_data contains the inode */ + + info_ptr->inode_ptr=ptr; + info_ptr->inode_offset=device_offset; /* device offset contains the inode's offset */ + + /* Reset the current position to the start */ + + info_ptr->global_block_num=ptr->i_block [0]; + info_ptr->global_block_offset=ptr->i_block [0]*file_system_info.block_size; + info_ptr->block_num=0; + info_ptr->file_offset=0; + /* Set the size of the directory */ + + info_ptr->blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size; + info_ptr->file_length=ptr->i_size; + + info_ptr->level=0; /* We start using direct blocks */ + info_ptr->display=HEX; /* This is not actually used */ + + info_ptr->dir_entry_num=0;info_ptr->dir_entries_count=0; /* We'll start at the first directory entry */ + info_ptr->dir_entry_offset=0; + + /* Find dir_entries_count */ + + info_ptr->dir_entries_count=count_dir_entries (); /* Set the total number of entries */ + + return (1); +} + +struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status) + +/* + This is the main function in this source file. Various actions are implemented using this basic function. + + This routine runs on all directory entries in the current directory. + For each entry, action is called. We'll act according to the return code of action: + + ABORT - Current dir entry is returned. + CONTINUE - Continue searching. + FOUND - Current dir entry is returned. + + If the last entry is reached, it is returned, along with an ABORT status. + + status is updated to the returned code of action. +*/ + +{ + struct struct_file_info info; /* Temporary variables used to */ + struct ext2_dir_entry *dir_entry_ptr; /* contain the current search entries */ + + int return_code; + + info=first_file_info; /* Start from the first entry - Read it */ + low_read (info.buffer,file_system_info.block_size,info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset); + + while (info.file_offset < info.file_length) { /* While we haven't reached the end */ + + *status=return_code=action (&info); /* Call the client function to test */ + /* the current entry */ + if (return_code==ABORT || return_code==FOUND) + return (info); /* Stop, if so asked */ + + /* Pass to the next entry */ + + dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset); + + info.dir_entry_num++; + info.dir_entry_offset+=dir_entry_ptr->rec_len; + info.file_offset+=dir_entry_ptr->rec_len; + + if (info.file_offset >= info.file_length) break; + + if (info.dir_entry_offset >= file_system_info.block_size) { /* We crossed a block boundary */ + /* Find the next block, */ + info.block_num++; + info.global_block_num=file_block_to_global_block (info.block_num,&info); + info.global_block_offset=info.global_block_num*file_system_info.block_size; + info.file_offset=info.block_num*file_system_info.block_size; + info.dir_entry_offset=0; + /* read it and update the pointer */ + + low_read (info.buffer,file_system_info.block_size,info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset); + + } + + } + + *status=ABORT;return (info); /* There was no match */ +} + +long count_dir_entries (void) + +/* + +This function counts the number of entries in the directory. We just call search_dir_entries till the end. +The client function is action_count, which just tell search_dir_entries to continue. + +*/ + +{ + int status; + + return (search_dir_entries (&action_count,&status).dir_entry_num); +} + +int action_count (struct struct_file_info *info) + +/* + +Used by count_dir_entries above - This function is called by search_dir_entries, and it tells it to continue +searching, until we get to the last entry. + +*/ + +{ + return (CONTINUE); /* Just continue searching */ +} + +void type_dir___cd (char *command_line) + +/* + Changes to a directory, relative to the current directory. + + This is a complicated operation, so I would repeat here the explanation from the design and + implementation document. + +1. The path is checked that it is not an absolute path (from /). If it is, we let the general cd to do the job by + calling directly type_ext2___cd. + +2. The path is divided into the nearest path and the rest of the path. For example, cd 1/2/3/4 is divided into + 1 and into 2/3/4. + +3. It is the first part of the path that we need to search for in the current directory. We search for it using + search_dir_entries, which accepts the action_name function as the client function. + +4. search_dir_entries will scan the entire entries and will call our action_name function for each entry. + In action_name, the required name will be checked against the name of the current entry, and FOUND will be + returned when a match occurs. + +5. If the required entry is found, we dispatch a remember command to insert the current inode (remember that + type_data is still intact and contains the inode of the current directory) into the object memory. + This is required to easily support symbolic links - If we find later that the inode pointed by the entry is + actually a symbolic link, we'll need to return to this point, and the above inode doesn't have (and can't have, + because of hard links) the information necessary to "move back". + +6. We then dispatch a followinode command to reach the inode pointed by the required entry. This command will + automatically change the type to ext2_inode - We are now at an inode, and all the inode commands are available. + +7. We check the inode's type to see if it is a directory. If it is, we dispatch a dir command to "enter the directory", + and recursively call ourself (The type is dir again) by dispatching a cd command, with the rest of the path + as an argument. + +8. If the inode's type is a symbolic link (only fast symbolic link were meanwhile implemented. I guess this is + typically the case.), we note the path it is pointing at, the saved inode is recalled, we dispatch dir to + get back to the original directory, and we call ourself again with the link path/rest of the path argument. + +9. In any other case, we just stop at the resulting inode. + +*/ + +{ + int status; + char *ptr,full_dir_name [500],dir_name [500],temp [500],temp2 [500]; + struct struct_file_info info; + struct ext2_dir_entry *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset); + + ptr=parse_word (command_line,dir_name); + + if (*ptr==0) { /* cd alone will enter the highlighted directory */ + strncpy (full_dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len); + full_dir_name [dir_entry_ptr->name_len]=0; + } + else + ptr=parse_word (ptr,full_dir_name); + + ptr=strchr (full_dir_name,'/'); + + if (ptr==full_dir_name) { /* Pathname is from root - Let the general cd do the job */ + sprintf (temp,"cd %s",full_dir_name);type_ext2___cd (temp);return; + } + + if (ptr==NULL) { + strcpy (dir_name,full_dir_name); + full_dir_name [0]=0; + } + + else { + strncpy (dir_name,full_dir_name,ptr-full_dir_name); + dir_name [ptr-full_dir_name]=0; + strcpy (full_dir_name,++ptr); + } + /* dir_name contains the current entry, while */ + /* full_dir_name contains the rest */ + + strcpy (name_search,dir_name); /* name_search is used to hold the required entry name */ + + if (dir_entry_ptr->name_len != strlen (dir_name) || + strncmp (dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len)!=0) + info=search_dir_entries (&action_name,&status); /* Search for the entry. Answer in info. */ + else { + status=FOUND;info=file_info; + } + + if (status==FOUND) { /* If found */ + file_info=info; /* Switch to it, by setting the global file_info */ + dispatch ("remember internal_variable"); /* Move the inode into the objects memory */ + + dispatch ("followinode"); /* Go to the inode pointed by this directory entry */ + + if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) {/* Symbolic link ? */ + + if (type_data.u.t_ext2_inode.i_size > 60) { /* I'm lazy, I guess :-) */ + wprintw (command_win,"Error - Sorry, Only fast symbolic link following is currently supported\n"); + refresh_command_win (); + return; + } + /* Get the pointed name and append the previous path */ + + strcpy (temp2,(unsigned char *) &type_data.u.t_ext2_inode.i_block); + strcat (temp2,"/"); + strcat (temp2,full_dir_name); + + dispatch ("recall internal_variable"); /* Return to the original inode */ + dispatch ("dir"); /* and to the directory */ + + sprintf (temp,"cd %s",temp2); /* And continue from there by dispatching a cd command */ + dispatch (temp); /* (which can call ourself or the general cd) */ + + return; + } + + if (S_ISDIR (type_data.u.t_ext2_inode.i_mode)) { /* Is it an inode of a directory ? */ + + dispatch ("dir"); /* Yes - Pass to the pointed directory */ + + if (full_dir_name [0] != 0) { /* And call ourself with the rest of the pathname */ + sprintf (temp,"cd %s",full_dir_name); + dispatch (temp); + } + + return; + } + + else { /* If we can't continue from here, we'll just stop */ + wprintw (command_win,"Can\'t continue - Stopping at last inode\n");refresh_command_win (); + return; + } + } + + wprintw (command_win,"Error - Directory entry %s not found.\n",dir_name); /* Hmm, an invalid path somewhere */ + refresh_command_win (); +} + +int action_name (struct struct_file_info *info) + +/* + +Compares the current search entry name (somewhere inside info) with the required name (in name_search). +Returns FOUND if found, or CONTINUE if not found. + +*/ + +{ + struct ext2_dir_entry *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry *) (info->buffer+info->dir_entry_offset); + + if (dir_entry_ptr->name_len != strlen (name_search)) + return (CONTINUE); + + if (strncmp (dir_entry_ptr->name,name_search,dir_entry_ptr->name_len)==0) + return (FOUND); + + return (CONTINUE); +} + +void type_dir___entry (char *command_line) + +/* + +Selects a directory entry according to its number. +search_dir_entries is used along with action_entry_num, in the same fashion as the previous usage of search_dir_entries. + +*/ + +{ + int status; + struct struct_file_info info; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument_not_specified\n");wrefresh (command_win); + return; + } + ptr=parse_word (ptr,buffer); + entry_num_search=atol (buffer); + + if (entry_num_search < 0 || entry_num_search >= file_info.dir_entries_count) { + wprintw (command_win,"Error - Entry number out of range\n");wrefresh (command_win); + return; + } + + info=search_dir_entries (&action_entry_num,&status); + if (status==FOUND) { + file_info=info; + dispatch ("show"); + return; + } +#ifdef DEBUG + internal_error ("dir_com","type_dir___entry","According to our gathered data, we should have found this entry"); +#endif +} + +int action_entry_num (struct struct_file_info *info) + +/* + +Used by the above function. Just compares the current number (in info) with the required one. + +*/ + +{ + if (info->dir_entry_num == entry_num_search) + return (FOUND); + + return (CONTINUE); +} + +void type_dir___followinode (char *command_line) + +/* + +Here we pass to the inode pointed by the current entry. +It involves computing the device offset of the inode and using directly the setoffset and settype commands. + +*/ +{ + long inode_offset; + char buffer [80]; + + struct ext2_dir_entry *dir_entry_ptr; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset); + + inode_offset=inode_num_to_inode_offset (dir_entry_ptr->inode); /* Compute the inode's offset */ + sprintf (buffer,"setoffset %ld",inode_offset);dispatch (buffer); /* Move to it */ + sprintf (buffer,"settype ext2_inode");dispatch (buffer); /* and set the type to an inode */ +} + +void type_dir___inode (char *command_line) + +/* + +Returns to the parent inode of the current directory. +This is trivial, as we type_data is still intact and contains the parent inode ! + +*/ + +{ + dispatch ("settype ext2_inode"); +} + + +void type_dir___show (char *command_line) + +/* + +We use search_dir_entries to run on all the entries. Each time, action_show will be called to show one entry. + +*/ + +{ + int status; + + wmove (show_pad,0,0); + show_pad_info.max_line=-1; + + search_dir_entries (&action_show,&status); + show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2; + refresh_show_pad (); + show_dir_status (); +} + +int action_show (struct struct_file_info *info) + +/* + +Show the current search entry (info) in one line. If the entry happens to be the current edited entry, it is highlighted. + +*/ + +{ + unsigned char temp [80]; + struct ext2_dir_entry *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry *) (info->buffer+info->dir_entry_offset); + + if (info->dir_entry_num == file_info.dir_entry_num) /* Highlight the current entry */ + wattrset (show_pad,A_REVERSE); + + strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len); /* The name is not terminated */ + temp [dir_entry_ptr->name_len]=0; + if (dir_entry_ptr->name_len > (COLS - 55) && COLS > 55) + temp [COLS-55]=0; + wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n", /* Display the various fields */ + dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp); + + show_pad_info.max_line++; + + if (info->dir_entry_num == file_info.dir_entry_num) + wattrset (show_pad,A_NORMAL); + + return (CONTINUE); /* And pass to the next */ +} + +void type_dir___next (char *command_line) + +/* + +This function moves to the next directory entry. It just uses the current information and the entry command. + +*/ + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + sprintf (buffer,"entry %ld",file_info.dir_entry_num+offset);dispatch (buffer); + +} + +void type_dir___prev (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + sprintf (buffer,"entry %ld",file_info.dir_entry_num-offset);dispatch (buffer); +} + +void show_dir_status (void) + +/* + +Various statistics about the directory. + +*/ + +{ + long inode_num; + + wmove (show_win,0,0); + wprintw (show_win,"Directory listing. Block %ld. ",file_info.global_block_num); + wprintw (show_win,"Directory entry %ld of %ld.\n",file_info.dir_entry_num,file_info.dir_entries_count-1); + wprintw (show_win,"Directory Offset %ld of %ld. ",file_info.file_offset,file_info.file_length-1); + + inode_num=inode_offset_to_inode_num (file_info.inode_offset); + wprintw (show_win,"File inode %ld. Indirection level %ld.\n",inode_num,file_info.level); + + refresh_show_win (); +} + +void type_dir___remember (char *command_line) + +/* + +This is overrided here because we don't remember a directory - It is too complicated. Instead, we remember the +inode of the current directory. + +*/ + +{ + int found=0; + long entry_num; + char *ptr,buffer [80]; + struct struct_descriptor *descriptor_ptr; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,"ext2_inode")==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=descriptor_ptr; + strcpy (remember_lifo.name [entry_num],buffer); + + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer); + wrefresh (command_win); +} + +void type_dir___set (char *command_line) + +/* + +Since the dir object doesn't have variables, we provide the impression that it has here. ext2_dir_entry was not used +because it is of variable length. + +*/ + +{ + int found=0; + unsigned char *ptr,buffer [80],variable [80],value [80],temp [80]; + struct ext2_dir_entry *dir_entry_ptr; + + dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset); + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Missing arguments\n");refresh_command_win (); + return; + } + parse_word (ptr,buffer); + ptr=strchr (buffer,'='); + if (ptr==NULL) { + wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return; + } + strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0; + strcpy (value,++ptr); + + if (strcasecmp ("inode",variable)==0) { + found=1; + dir_entry_ptr->inode=atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->inode);refresh_command_win (); + + } + + if (strcasecmp ("rec_len",variable)==0) { + found=1; + dir_entry_ptr->rec_len=(unsigned int) atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->rec_len);refresh_command_win (); + + } + + if (strcasecmp ("name_len",variable)==0) { + found=1; + dir_entry_ptr->name_len=(unsigned int) atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->name_len);refresh_command_win (); + + } + + if (strcasecmp ("name",variable)==0) { + found=1; + if (strlen (value) > dir_entry_ptr->name_len) { + wprintw (command_win,"Error - Length of name greater then name_len\n"); + refresh_command_win ();return; + } + strncpy (dir_entry_ptr->name,value,strlen (value)); + wprintw (command_win,"Variable %s set to %s\n",variable,value);refresh_command_win (); + + } + + if (found) { + wattrset (show_pad,A_REVERSE); + strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len); + temp [dir_entry_ptr->name_len]=0; + wmove (show_pad,file_info.dir_entry_num,0); + wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n", + dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp); + wattrset (show_pad,A_NORMAL); + show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2; + refresh_show_pad (); + show_dir_status (); + } + + else { + wprintw (command_win,"Error - Variable %s not found\n",variable); + refresh_command_win (); + } + +} + +void type_dir___writedata (char *command_line) + +/* + +We need to override this since the data is not in type_data. Instead, we have to write the buffer which corresponds +to the current block. + +*/ + +{ + low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + return; +} diff --git a/ext2ed/disk.c b/ext2ed/disk.c new file mode 100644 index 00000000..b754bf34 --- /dev/null +++ b/ext2ed/disk.c @@ -0,0 +1,238 @@ +/* + +/usr/src/ext2ed/disk.c + +A part of the extended file system 2 disk editor. + +------------------------------------------------- +The filesystem's disk activity pass through here. +------------------------------------------------- + +This file is acting as a filter - Before we pass an actual read or write request to the operating system, we +double check the various permissions and possible errors here. + +The major update which needs to be done here is switching to the use of the llseek system call, so that we will +be able to support ext2 filesystems up to 4 TB. Currently, due to the standard fseek usage, we can't handle +filesystems bigger than 4 GB. The limit is actually 2 GB because I used long rather than unsigned long long at too +many places in the program. To conclude - This upgrade needs to be done carefuly; There are many places to change. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include +#include +#include +#include + +#include "ext2ed.h" + +int write_access; + +int low_read (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +This function is used when we need to read something from the filesystem. + +*/ + +{ + +#ifdef DEBUG + + char temp [80]; + + if (device_handle==NULL) { /* Check that a device is indeed open */ + internal_error ("No device opened yet read requested","disk","low_read"); + return (0); + } + if (offset > file_system_info.file_system_size) { /* Check that the offset is within limits */ + sprintf (temp,"Seek offset %ld is out of range",offset); + internal_error (temp,"disk","low_read"); + return (0); + } + +#endif + + if ( (fseek (device_handle,offset,SEEK_SET))==-1) { /* Seek to the required offset */ + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name); + refresh_command_win (); + return (0); + }; + + if ( (fread (buffer,1,length,device_handle))==-1) { /* And do the actual reading */ + wprintw (command_win,"Error - Failed to read from offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + return (1); +} + +int low_write (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +This is used to change something in the filesystem. +write_access is checked to see if we are allowed to do the actual writing. +As a double safety measure, AllowChanges is rechecked here. +If logging is enabled, we log the change before writing it to the device. + +*/ +{ + char temp [80]; + + if (!write_access) { + wprintw (command_win,"Error - Write access not aviable (use enablewrite)\n"); + return (0); + } + +#ifdef DEBUG + + if (!AllowChanges) { + internal_error ("AllowChanges=0 yet enablewrite succeeded","disk","low_write"); + return (0); + } + + if (device_handle==NULL) { + internal_error ("No device opened yet read requested","disk","low_write"); + return (0); + } + + if (offset > file_system_info.file_system_size) { + sprintf (temp,"Seek offset %ld is out of range",offset); + internal_error (temp,"disk","low_write"); + return (0); + } + +#endif + + if (LogChanges) + if (!log_changes (buffer,length,offset)) + return (0); + + if ( (fseek (device_handle,offset,SEEK_SET))==-1) { + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + + if ( (fwrite (buffer,1,length,device_handle))==-1) { + wprintw (command_win,"Error - Failed to write to offset %ld in device %s\n",offset,device_name); + refresh_command_win ();return (0); + }; + + wprintw (command_win,"Data written");refresh_command_win (); + return (1); +} + +int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset) + +/* + +Log the change in a primitive form - An hex dump of the data before the change and after the change. +The hex bytes are converted to text, so that they will be readable with a standard text editor. + +*/ + +{ + unsigned char *original; + + int i; + time_t current_time; + FILE *fp; + + if ((fp=fopen (LogFile,"a+"))==NULL) { + wprintw (command_win,"Error - Unable to open log file %s\n",LogFile); + refresh_command_win ();return (0); + }; + + current_time=time (NULL); + + fprintf (fp,"\n----- EXT2ED log begin -----\n\n"); + fprintf (fp,"Time: %s\nDevice: %s\n",ctime ((time_t *) ¤t_time),device_name); + fprintf (fp,"Offset: %lu\nLength: %lu\n",offset,length); + + original=(unsigned char *) malloc (length*sizeof (unsigned char)); + + if (original==NULL) { + wprintw (command_win,"Fatal error - Can\'t allocate %lu bytes !"); + refresh_command_win ();fclose (fp);return (0); + } + + if (!low_read (original,length,offset)) { + fclose (fp);return (0); + } + + fprintf (fp,"\nOriginal data:\n\n"); + + for (i=0;iname,"ext2_dir_entry")==0) + current_type->length=type_data.u.t_ext2_dir_entry.rec_len; + + return (1); +} + +int write_type_data (void) + +{ + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n"); + refresh_command_win (); + return (0); + } + + if (device_offset==-1) { + wprintw (command_win,"Error - No offset set\n"); + refresh_command_win (); + return (0); + } + + if (low_write (type_data.u.buffer,file_system_info.block_size,device_offset)==0) + return (0); + + return (1); +} + diff --git a/ext2ed/doc/Ext2fs-overview-0.1.sgml b/ext2ed/doc/Ext2fs-overview-0.1.sgml new file mode 100644 index 00000000..e1740d46 --- /dev/null +++ b/ext2ed/doc/Ext2fs-overview-0.1.sgml @@ -0,0 +1,898 @@ + + + + + + + +
+ +The extended-2 filesystem overview +<author>Gadi Oxman, tgud@tochnapc2.technion.ac.il +<date>v0.1, August 3 1995 +<toc> + +<!-- Begin of document --> + +<sect>Preface +<p> + +This document attempts to present an overview of the internal structure of +the ext2 filesystem. It was written in summer 95, while I was working on the +<tt>ext2 filesystem editor project (EXT2ED)</>. + +In the process of constructing EXT2ED, I acquired knowledge of the various +design aspects of the the ext2 filesystem. This document is a result of an +effort to document this knowledge. + +This is only the initial version of this document. It is obviously neither +error-prone nor complete, but at least it provides a starting point. + +In the process of learning the subject, I have used the following sources / +tools: +<itemize> +<item> Experimenting with EXT2ED, as it was developed. +<item> The ext2 kernel sources: + <itemize> + <item> The main ext2 include file, + <tt>/usr/include/linux/ext2_fs.h</> + <item> The contents of the directory <tt>/usr/src/linux/fs/ext2</>. + <item> The VFS layer sources (only a bit). + </itemize> +<item> The slides: The Second Extended File System, Current State, Future + Development, by <tt>Remy Card</>. +<item> The slides: Optimisation in File Systems, by <tt>Stephen Tweedie</>. +<item> The various ext2 utilities. +</itemize> + +<sect>Introduction +<p> + +The <tt>Second Extended File System (Ext2fs)</> is very popular among Linux +users. If you use Linux, chances are that you are using the ext2 filesystem. + +Ext2fs was designed by <tt>Remy Card</> and <tt>Wayne Davison</>. It was +implemented by <tt>Remy Card</> and was further enhanced by <tt>Stephen +Tweedie</> and <tt>Theodore Ts'o</>. + +The ext2 filesystem is still under development. I will document here +version 0.5a, which is distributed along with Linux 1.2.x. At this time of +writing, the most recent version of Linux is 1.3.13, and the version of the +ext2 kernel source is 0.5b. A lot of fancy enhancements are planned for the +ext2 filesystem in Linux 1.3, so stay tuned. + +<sect>A filesystem - Why do we need it ? +<p> + +I thought that before we dive into the various small details, I'll reserve a +few minutes for the discussion of filesystems from a general point of view. + +A <tt>filesystem</> consists of two word - <tt>file</> and <tt>system</>. + +Everyone knows the meaning of the word <tt>file</> - A bunch of data put +somewhere. where ? This is an important question. I, for example, usually +throw almost everything into a single drawer, and have difficulties finding +something later. + +This is where the <tt>system</> comes in - Instead of just throwing the data +to the device, we generalize and construct a <tt>system</> which will +virtualize for us a nice and ordered structure in which we could arrange our +data in much the same way as books are arranged in a library. The purpose of +the filesystem, as I understand it, is to make it easy for us to update and +maintain our data. + +Normally, by <tt>mounting</> filesystems, we just use the nice and logical +virtual structure. However, the disk knows nothing about that - The device +driver views the disk as a large continuous paper in which we can write notes +wherever we wish. It is the task of the filesystem management code to store +bookkeeping information which will serve the kernel for showing us the nice +and ordered virtual structure. + +In this document, we consider one particular administrative structure - The +Second Extended Filesystem. + +<sect>The Linux VFS layer +<p> + +When Linux was first developed, it supported only one filesystem - The +<tt>Minix</> filesystem. Today, Linux has the ability to support several +filesystems concurrently. This was done by the introduction of another layer +between the kernel and the filesystem code - The Virtual File System (VFS). + +The kernel "speaks" with the VFS layer. The VFS layer passes the kernel's +request to the proper filesystem management code. I haven't learned much of +the VFS layer as I didn't need it for the construction of EXT2ED so that I +can't elaborate on it. Just be aware that it exists. + +<sect>About blocks and block groups +<p> + +In order to ease management, the ext2 filesystem logically divides the disk +into small units called <tt>blocks</>. A block is the smallest unit which +can be allocated. Each block in the filesystem can be <tt>allocated</> or +<tt>free</>. +<footnote> +The Ext2fs source code refers to the concept of <tt>fragments</>, which I +believe are supposed to be sub-block allocations. As far as I know, +fragments are currently unsupported in Ext2fs. +</footnote> +The block size can be selected to be 1024, 2048 or 4096 bytes when creating +the filesystem. + +Ext2fs groups together a fixed number of sequential blocks into a <tt>group +block</>. The resulting situation is that the filesystem is managed as a +series of group blocks. This is done in order to keep related information +physically close on the disk and to ease the management task. As a result, +much of the filesystem management reduces to management of a single blocks +group. + +<sect>The view of inodes from the point of view of a blocks group +<p> + +Each file in the filesystem is reserved a special <tt>inode</>. I don't want +to explain inodes now. Rather, I would like to treat it as another resource, +much like a <tt>block</> - Each blocks group contains a limited number of +inode, while any specific inode can be <tt>allocated</> or +<tt>unallocated</>. + +<sect>The group descriptors +<p> + +Each blocks group is accompanied by a <tt>group descriptor</>. The group +descriptor summarizes some necessary information about the specific group +block. Follows the definition of the group descriptor, as defined in +/usr/include/linux/ext2_fs.h: + +<tscreen><code> +struct ext2_group_desc +{ + __u32 bg_block_bitmap; /* Blocks bitmap block */ + __u32 bg_inode_bitmap; /* Inodes bitmap block */ + __u32 bg_inode_table; /* Inodes table block */ + __u16 bg_free_blocks_count; /* Free blocks count */ + __u16 bg_free_inodes_count; /* Free inodes count */ + __u16 bg_used_dirs_count; /* Directories count */ + __u16 bg_pad; + __u32 bg_reserved[3]; +}; +</code></tscreen> + +The last three variables: <tt>bg_free_blocks_count, bg_free_inodes_count and +bg_used_dirs_count</> provide statistics about the use of the three +resources in a blocks group - The <tt>blocks</>, the <tt>inodes</> and the +<tt>directories</>. I believe that they are used by the kernel for balancing +the load between the various blocks groups. + +<tt>bg_block_bitmap</> contains the block number of the <tt>block allocation +bitmap block</>. This is used to allocate / deallocate each block in the +specific blocks group. + +<tt>bg_inode_bitmap</> is fully analogous to the previous variable - It +contains the block number of the <tt>inode allocation bitmap block</>, which +is used to allocate / deallocate each specific inode in the filesystem. + +<tt>bg_inode_table</> contains the block number of the start of the +<tt>inode table of the current blocks group</>. The <tt>inode table</> is +just the actual inodes which are reserved for the current block. + +The block bitmap block, inode bitmap block and the inode table are created +when the filesystem is created. + +The group descriptors are placed one after the other. Together they make the +<tt>group descriptors table</>. + +Each blocks group contains the entire table of group descriptors in its +second block, right after the superblock. However, only the first copy (in +group 0) is actually used by the kernel. The other copies are there for +backup purposes and can be of use if the main copy gets corrupted. + +<sect>The block bitmap allocation block +<p> + +Each blocks group contains one special block which is actually a map of the +entire blocks in the group, with respect to their allocation status. Each +<tt>bit</> in the block bitmap indicated whether a specific block in the +group is used or free. + +The format is actually quite simple - Just view the entire block as a series +of bits. For example, + +Suppose the block size is 1024 bytes. As such, there is a place for +1024*8=8192 blocks in a group block. This number is one of the fields in the +filesystem's <tt>superblock</>, which will be explained later. + +<itemize> +<item> Block 0 in the blocks group is managed by bit 0 of byte 0 in the bitmap + block. +<item> Block 7 in the blocks group is managed by bit 7 of byte 0 in the bitmap + block. +<item> Block 8 in the blocks group is managed by bit 0 of byte 1 in the bitmap + block. +<item> Block 8191 in the blocks group is managed by bit 7 of byte 1023 in the + bitmap block. +</itemize> + +A value of "<tt>1</>" in the appropriate bit signals that the block is +allocated, while a value of "<tt>0</>" signals that the block is +unallocated. + +You will probably notice that typically, all the bits in a byte contain the +same value, making the byte's value <tt>0</> or <tt>0ffh</>. This is done by +the kernel on purpose in order to group related data in physically close +blocks, since the physical device is usually optimized to handle such a close +relationship. + +<sect>The inode allocation bitmap +<p> + +The format of the inode allocation bitmap block is exactly like the format of +the block allocation bitmap block. The explanation above is valid here, with +the work <tt>block</> replaced by <tt>inode</>. Typically, there are much less +inodes then blocks in a blocks group and thus only part of the inode bitmap +block is used. The number of inodes in a blocks group is another variable +which is listed in the <tt>superblock</>. + +<sect>On the inode and the inode tables +<p> + +An inode is a main resource in the ext2 filesystem. It is used for various +purposes, but the main two are: +<itemize> +<item> Support of files +<item> Support of directories +</itemize> + +Each file, for example, will allocate one inode from the filesystem +resources. + +An ext2 filesystem has a total number of available inodes which is determined +while creating the filesystem. When all the inodes are used, for example, you +will not be able to create an additional file even though there will still +be free blocks on the filesystem. + +Each inode takes up 128 bytes in the filesystem. By default, <tt>mke2fs</> +reserves an inode for each 4096 bytes of the filesystem space. + +The inodes are placed in several tables, each of which contains the same +number of inodes and is placed at a different blocks group. The goal is to +place inodes and their related files in the same blocks group because of +locality arguments. + +The number of inodes in a blocks group is available in the superblock variable +<tt>s_inodes_per_group</>. For example, if there are 2000 inodes per group, +group 0 will contain the inodes 1-2000, group 2 will contain the inodes +2001-4000, and so on. + +Each inode table is accessed from the group descriptor of the specific +blocks group which contains the table. + +Follows the structure of an inode in Ext2fs: + +<tscreen><code> +struct ext2_inode { + __u16 i_mode; /* File mode */ + __u16 i_uid; /* Owner Uid */ + __u32 i_size; /* Size in bytes */ + __u32 i_atime; /* Access time */ + __u32 i_ctime; /* Creation time */ + __u32 i_mtime; /* Modification time */ + __u32 i_dtime; /* Deletion Time */ + __u16 i_gid; /* Group Id */ + __u16 i_links_count; /* Links count */ + __u32 i_blocks; /* Blocks count */ + __u32 i_flags; /* File flags */ + union { + struct { + __u32 l_i_reserved1; + } linux1; + struct { + __u32 h_i_translator; + } hurd1; + struct { + __u32 m_i_reserved1; + } masix1; + } osd1; /* OS dependent 1 */ + __u32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */ + __u32 i_version; /* File version (for NFS) */ + __u32 i_file_acl; /* File ACL */ + __u32 i_dir_acl; /* Directory ACL */ + __u32 i_faddr; /* Fragment address */ + union { + struct { + __u8 l_i_frag; /* Fragment number */ + __u8 l_i_fsize; /* Fragment size */ + __u16 i_pad1; + __u32 l_i_reserved2[2]; + } linux2; + struct { + __u8 h_i_frag; /* Fragment number */ + __u8 h_i_fsize; /* Fragment size */ + __u16 h_i_mode_high; + __u16 h_i_uid_high; + __u16 h_i_gid_high; + __u32 h_i_author; + } hurd2; + struct { + __u8 m_i_frag; /* Fragment number */ + __u8 m_i_fsize; /* Fragment size */ + __u16 m_pad1; + __u32 m_i_reserved2[2]; + } masix2; + } osd2; /* OS dependent 2 */ +}; +</code></tscreen> + +<sect1>The allocated blocks +<p> + +The basic functionality of an inode is to group together a series of +allocated blocks. There is no limitation on the allocated blocks - Each +block can be allocated to each inode. Nevertheless, block allocation will +usually be done in series to take advantage of the locality principle. + +The inode is not always used in that way. I will now explain the allocation +of blocks, assuming that the current inode type indeed refers to a list of +allocated blocks. + +It was found experimently that many of the files in the filesystem are +actually quite small. To take advantage of this effect, the kernel provides +storage of up to 12 block numbers in the inode itself. Those blocks are +called <tt>direct blocks</>. The advantage is that once the kernel has the +inode, it can directly access the file's blocks, without an additional disk +access. Those 12 blocks are directly specified in the variables +<tt>i_block[0] to i_block[11]</>. + +<tt>i_block[12]</> is the <tt>indirect block</> - The block pointed by +i_block[12] will <tt>not</> be a data block. Rather, it will just contain a +list of direct blocks. For example, if the block size is 1024 bytes, since +each block number is 4 bytes long, there will be place for 256 indirect +blocks. That is, block 13 till block 268 in the file will be accessed by the +<tt>indirect block</> method. The penalty in this case, compared to the +direct blocks case, is that an additional access to the device is needed - +We need <tt>two</> accesses to reach the required data block. + +In much the same way, <tt>i_block[13]</> is the <tt>double indirect block</> +and <tt>i_block[14]</> is the <tt>triple indirect block</>. + +<tt>i_block[13]</> points to a block which contains pointers to indirect +blocks. Each one of them is handled in the way described above. + +In much the same way, the triple indirect block is just an additional level +of indirection - It will point to a list of double indirect blocks. + +<sect1>The i_mode variable +<p> + +The i_mode variable is used to determine the <tt>inode type</> and the +associated <tt>permissions</>. It is best described by representing it as an +octal number. Since it is a 16 bit variable, there will be 6 octal digits. +Those are divided into two parts - The rightmost 4 digits and the leftmost 2 +digits. + +<sect2>The rightmost 4 octal digits +<p> + +The rightmost 4 digits are <tt>bit options</> - Each bit has its own +purpose. + +The last 3 digits (Octal digits 0,1 and 2) are just the usual permissions, +in the known form <tt>rwxrwxrwx</>. Digit 2 refers to the user, digit 1 to +the group and digit 2 to everyone else. They are used by the kernel to grant +or deny access to the object presented by this inode. +<footnote> +A <tt>smarter</> permissions control is one of the enhancements planned for +Linux 1.3 - The ACL (Access Control Lists). Actually, from browsing of the +kernel source, some of the ACL handling is already done. +</footnote> + +Bit number 9 signals that the file (I'll refer to the object presented by +the inode as file even though it can be a special device, for example) is +<tt>set VTX</>. I still don't know what is the meaning of "VTX". + +Bit number 10 signals that the file is <tt>set group id</> - I don't know +exactly the meaning of the above either. + +Bit number 11 signals that the file is <tt>set user id</>, which means that +the file will run with an effective user id root. + +<sect2>The leftmost two octal digits +<p> + +Note the the leftmost octal digit can only be 0 or 1, since the total number +of bits is 16. + +Those digits, as opposed to the rightmost 4 digits, are not bit mapped +options. They determine the type of the "file" to which the inode belongs: +<itemize> +<item> <tt>01</> - The file is a <tt>FIFO</>. +<item> <tt>02</> - The file is a <tt>character device</>. +<item> <tt>04</> - The file is a <tt>directory</>. +<item> <tt>06</> - The file is a <tt>block device</>. +<item> <tt>10</> - The file is a <tt>regular file</>. +<item> <tt>12</> - The file is a <tt>symbolic link</>. +<item> <tt>14</> - The file is a <tt>socket</>. +</itemize> + +<sect1>Time and date +<p> + +Linux records the last time in which various operations occured with the +file. The time and date are saved in the standard C library format - The +number of seconds which passed since 00:00:00 GMT, January 1, 1970. The +following times are recorded: +<itemize> +<item> <tt>i_ctime</> - The time in which the inode was last allocated. In + other words, the time in which the file was created. +<item> <tt>i_mtime</> - The time in which the file was last modified. +<item> <tt>i_atime</> - The time in which the file was last accessed. +<item> <tt>i_dtime</> - The time in which the inode was deallocated. In + other words, the time in which the file was deleted. +</itemize> + +<sect1>i_size +<p> + +<tt>i_size</> contains information about the size of the object presented by +the inode. If the inode corresponds to a regular file, this is just the size +of the file in bytes. In other cases, the interpretation of the variable is +different. + +<sect1>User and group id +<p> + +The user and group id of the file are just saved in the variables +<tt>i_uid</> and <tt>i_gid</>. + +<sect1>Hard links +<p> + +Later, when we'll discuss the implementation of directories, it will be +explained that each <tt>directory entry</> points to an inode. It is quite +possible that a <tt>single inode</> will be pointed to from <tt>several</> +directories. In that case, we say that there exist <tt>hard links</> to the +file - The file can be accessed from each of the directories. + +The kernel keeps track of the number of hard links in the variable +<tt>i_links_count</>. The variable is set to "1" when first allocating the +inode, and is incremented with each additional link. Deletion of a file will +delete the current directory entry and will decrement the number of links. +Only when this number reaches zero, the inode will be actually deallocated. + +The name <tt>hard link</> is used to distinguish between the alias method +described above, to another alias method called <tt>symbolic linking</>, +which will be described later. + +<sect1>The Ext2fs extended flags +<p> + +The ext2 filesystem associates additional flags with an inode. The extended +attributes are stored in the variable <tt>i_flags</>. <tt>i_flags</> is a 32 +bit variable. Only the 7 rightmost bits are defined. Of them, only 5 bits +are used in version 0.5a of the filesystem. Specifically, the +<tt>undelete</> and the <tt>compress</> features are not implemented, and +are to be introduced in Linux 1.3 development. + +The currently available flags are: +<itemize> +<item> bit 0 - Secure deletion. + + When this bit is on, the file's blocks are zeroed when the file is + deleted. With this bit off, they will just be left with their + original data when the inode is deallocated. +<item> bit 1 - Undelete. + + This bit is not supported yet. It will be used to provide an + <tt>undelete</> feature in future Ext2fs developments. +<item> bit 2 - Compress file. + + This bit is also not supported. The plan is to offer "compression on + the fly" in future releases. +<item> bit 3 - Synchronous updates. + + With this bit on, the meta-data will be written synchronously to the + disk, as if the filesystem was mounted with the "sync" mount option. +<item> bit 4 - Immutable file. + + When this bit is on, the file will stay as it is - Can not be + changed, deleted, renamed, no hard links, etc, before the bit is + cleared. +<item> bit 5 - Append only file. + + With this option active, data will only be appended to the file. +<item> bit 6 - Do not dump this file. + + I think that this bit is used by the port of dump to linux (ported by + <tt>Remy Card</>) to check if the file should not be dumped. +</itemize> + +<sect1>Symbolic links +<p> + +The <tt>hard links</> presented above are just another pointers to the same +inode. The important aspect is that the inode number is <tt>fixed</> when +the link is created. This means that the implementation details of the +filesystem are visible to the user - In a pure abstract usage of the +filesystem, the user should not care about inodes. + +The above causes several limitations: +<itemize> +<item> Hard links can be done only in the same filesystem. This is obvious, + since a hard link is just an inode number in some directory entry, + and the above elements are filesystem specific. +<item> You can not "replace" the file which is pointed to by the hard link + after the link creation. "Replacing" the file in one directory will + still leave the original file in the other directory - The + "replacement" will not deallocate the original inode, but rather + allocate another inode for the new version, and the directory entry + at the other place will just point to the old inode number. +</itemize> + +<tt>Symbolic link</>, on the other hand, is analyzed at <tt>run time</>. A +symbolic link is just a <tt>pathname</> which is accessible from an inode. +As such, it "speaks" in the language of the abstract filesystem. When the +kernel reaches a symbolic link, it will <tt>follow it in run time</> using +its normal way of reaching directories. + +As such, symbolic link can be made <tt>across different filesystems</> and a +replacement of a file with a new version will automatically be active on all +its symbolic links. + +The disadvantage is that hard link doesn't consume space except to a small +directory entry. Symbolic link, on the other hand, consumes at least an +inode, and can also consume one block. + +When the inode is identified as a symbolic link, the kernel needs to find +the path to which it points. + +<sect2>Fast symbolic links +<p> + +When the pathname contains up to 64 bytes, it can be saved directly in the +inode, on the <tt>i_block[0] - i_block[15]</> variables, since those are not +needed in that case. This is called <tt>fast</> symbolic link. It is fast +because the pathname resolution can be done using the inode itself, without +accessing additional blocks. It is also economical, since it allocates only +an inode. The length of the pathname is stored in the <tt>i_size</> +variable. + +<sect2>Slow symbolic links +<p> + +Starting from 65 bytes, additional block is allocated (by the use of +<tt>i_block[0]</>) and the pathname is stored in it. It is called slow +because the kernel needs to read additional block to resolve the pathname. +The length is again saved in <tt>i_size</>. + +<sect1>i_version +<p> + +<tt>i_version</> is used with regard to Network File System. I don't know +its exact use. + +<sect1>Reserved variables +<p> + +As far as I know, the variables which are connected to ACL and fragments +are not currently used. They will be supported in future versions. + +Ext2fs is being ported to other operating systems. As far as I know, +at least in linux, the os dependent variables are also not used. + +<sect1>Special reserved inodes +<p> + +The first ten inodes on the filesystem are special inodes: +<itemize> +<item> Inode 1 is the <tt>bad blocks inode</> - I believe that its data + blocks contain a list of the bad blocks in the filesystem, which + should not be allocated. +<item> Inode 2 is the <tt>root inode</> - The inode of the root directory. + It is the starting point for reaching a known path in the filesystem. +<item> Inode 3 is the <tt>acl index inode</>. Access control lists are + currently not supported by the ext2 filesystem, so I believe this + inode is not used. +<item> Inode 4 is the <tt>acl data inode</>. Of course, the above applies + here too. +<item> Inode 5 is the <tt>boot loader inode</>. I don't know its + usage. +<item> Inode 6 is the <tt>undelete directory inode</>. It is also a + foundation for future enhancements, and is currently not used. +<item> Inodes 7-10 are <tt>reserved</> and currently not used. +</itemize> + +<sect>Directories +<p> + +A directory is implemented in the same way as files are implemented (with +the direct blocks, indirect blocks, etc) - It is just a file which is +formatted with a special format - A list of directory entries. + +Follows the definition of a directory entry: + +<tscreen><code> +struct ext2_dir_entry { + __u32 inode; /* Inode number */ + __u16 rec_len; /* Directory entry length */ + __u16 name_len; /* Name length */ + char name[EXT2_NAME_LEN]; /* File name */ +}; +</code></tscreen> + +Ext2fs supports file names of varying lengths, up to 255 bytes. The +<tt>name</> field above just contains the file name. Note that it is +<tt>not zero terminated</>; Instead, the variable <tt>name_len</> contains +the length of the file name. + +The variable <tt>rec_len</> is provided because the directory entries are +padded with zeroes so that the next entry will be in an offset which is +a multiplition of 4. The resulting directory entry size is stored in +<tt>rec_len</>. If the directory entry is the last in the block, it is +padded with zeroes till the end of the block, and rec_len is updated +accordingly. + +The <tt>inode</> variable points to the inode of the above file. + +Deletion of directory entries is done by appending of the deleted entry +space to the previous (or next, I am not sure) entry. + +<sect>The superblock +<p> + +The <tt>superblock</> is a block which contains information which describes +the state of the internal filesystem. + +The superblock is located at the <tt>fixed offset 1024</> in the device. Its +length is 1024 bytes also. + +The superblock, like the group descriptors, is copied on each blocks group +boundary for backup purposes. However, only the main copy is used by the +kernel. + +The superblock contain three types of information: +<itemize> +<item> Filesystem parameters which are fixed and which were determined when + this specific filesystem was created. Some of those parameters can + be different in different installations of the ext2 filesystem, but + can not be changed once the filesystem was created. +<item> Filesystem parameters which are tunable - Can always be changed. +<item> Information about the current filesystem state. +</itemize> + +Follows the superblock definition: + +<tscreen><code> +struct ext2_super_block { + __u32 s_inodes_count; /* Inodes count */ + __u32 s_blocks_count; /* Blocks count */ + __u32 s_r_blocks_count; /* Reserved blocks count */ + __u32 s_free_blocks_count; /* Free blocks count */ + __u32 s_free_inodes_count; /* Free inodes count */ + __u32 s_first_data_block; /* First Data Block */ + __u32 s_log_block_size; /* Block size */ + __s32 s_log_frag_size; /* Fragment size */ + __u32 s_blocks_per_group; /* # Blocks per group */ + __u32 s_frags_per_group; /* # Fragments per group */ + __u32 s_inodes_per_group; /* # Inodes per group */ + __u32 s_mtime; /* Mount time */ + __u32 s_wtime; /* Write time */ + __u16 s_mnt_count; /* Mount count */ + __s16 s_max_mnt_count; /* Maximal mount count */ + __u16 s_magic; /* Magic signature */ + __u16 s_state; /* File system state */ + __u16 s_errors; /* Behaviour when detecting errors */ + __u16 s_pad; + __u32 s_lastcheck; /* time of last check */ + __u32 s_checkinterval; /* max. time between checks */ + __u32 s_creator_os; /* OS */ + __u32 s_rev_level; /* Revision level */ + __u16 s_def_resuid; /* Default uid for reserved blocks */ + __u16 s_def_resgid; /* Default gid for reserved blocks */ + __u32 s_reserved[235]; /* Padding to the end of the block */ +}; +</code></tscreen> + +<sect1>superblock identification +<p> + +The ext2 filesystem's superblock is identified by the <tt>s_magic</> field. +The current ext2 magic number is 0xEF53. I presume that "EF" means "Extended +Filesystem". In versions of the ext2 filesystem prior to 0.2B, the magic +number was 0xEF51. Those filesystems are not compatible with the current +versions; Specifically, the group descriptors definition is different. I +doubt if there still exists such a installation. + +<sect1>Filesystem fixed parameters +<p> + +By using the word <tt>fixed</>, I mean fixed with respect to a particular +installation. Those variables are usually not fixed with respect to +different installations. + +The <tt>block size</> is determined by using the <tt>s_log_block_size</> +variable. The block size is 1024*pow (2,s_log_block_size) and should be +between 1024 and 4096. The available options are 1024, 2048 and 4096. + +<tt>s_inodes_count</> contains the total number of available inodes. + +<tt>s_blocks_count</> contains the total number of available blocks. + +<tt>s_first_data_block</> specifies in which of the <tt>device block</> the +<tt>superblock</> is present. The superblock is always present at the fixed +offset 1024, but the device block numbering can differ. For example, if the +block size is 1024, the superblock will be at <tt>block 1</> with respect to +the device. However, if the block size is 4096, offset 1024 is included in +<tt>block 0</> of the device, and in that case <tt>s_first_data_block</> +will contain 0. At least this is how I understood this variable. + +<tt>s_blocks_per_group</> contains the number of blocks which are grouped +together as a blocks group. + +<tt>s_inodes_per_group</> contains the number of inodes available in a group +block. I think that this is always the total number of inodes divided by the +number of blocks groups. + +<tt>s_creator_os</> contains a code number which specifies the operating +system which created this specific filesystem: +<itemize> +<item> <tt>Linux</> :-) is specified by the value <tt>0</>. +<item> <tt>Hurd</> is specified by the value <tt>1</>. +<item> <tt>Masix</> is specified by the value <tt>2</>. +</itemize> + +<tt>s_rev_level</> contains the major version of the ext2 filesystem. +Currently this is always <tt>0</>, as the most recent version is 0.5B. It +will probably take some time until we reach version 1.0. + +As far as I know, fragments (sub-block allocations) are currently not +supported and hence a block is equal to a fragment. As a result, +<tt>s_log_frag_size</> and <tt>s_frags_per_group</> are always equal to +<tt>s_log_block_size</> and <tt>s_blocks_per_group</>, respectively. + +<sect1>Ext2fs error handling +<p> + +The ext2 filesystem error handling is based on the following philosophy: +<enum> +<item> Identification of problems is done by the kernel code. +<item> The correction task is left to an external utility, such as + <tt>e2fsck by Theodore Ts'o</> for <tt>automatic</> analysis and + correction, or perhaps <tt>debugfs by Theodore Ts'o</> and + <tt>EXT2ED by myself</>, for <tt>hand</> analysis and correction. +</enum> + +The <tt>s_state</> variable is used by the kernel to pass the identification +result to third party utilities: +<itemize> +<item> <tt>bit 0</> of s_state is reset when the partition is mounted and + set when the partition is unmounted. Thus, a value of 0 on an + unmounted filesystem means that the filesystem was not unmounted + properly - The filesystem is not "clean" and probably contains + errors. +<item> <tt>bit 1</> of s_state is set by the kernel when it detects an + error in the filesystem. A value of 0 doesn't mean that there isn't + an error in the filesystem, just that the kernel didn't find any. +</itemize> + +The kernel behavior when an error is found is determined by the user tunable +parameter <tt>s_errors</>: +<itemize> +<item> The kernel will ignore the error and continue if <tt>s_errors=1</>. +<item> The kernel will remount the filesystem in read-only mode if + <tt>s_errors=2</>. +<item> A kernel panic will be issued if <tt>s_errors=3</>. +</itemize> + +The default behavior is to ignore the error. + +<sect1>Additional parameters used by e2fsck +<p> + +Of-course, <tt>e2fsck</> will check the filesystem if errors were detected +or if the filesystem is not clean. + +In addition, each time the filesystem is mounted, <tt>s_mnt_count</> is +incremented. When s_mnt_count reaches <tt>s_max_mnt_count</>, <tt>e2fsck</> +will force a check on the filesystem even though it may be clean. It will +then zero s_mnt_count. <tt>s_max_mnt_count</> is a tunable parameter. + +E2fsck also records the last time in which the file system was checked in +the <tt>s_lastcheck</> variable. The user tunable parameter +<tt>s_checkinterval</> will contain the number of seconds which are allowed +to pass since <tt>s_lastcheck</> until a check is reforced. A value of +<tt>0</> disables time-based check. + +<sect1>Additional user tunable parameters +<p> + +<tt>s_r_blocks_count</> contains the number of disk blocks which are +reserved for root, the user whose id number is <tt>s_def_resuid</> and the +group whose id number is <tt>s_deg_resgid</>. The kernel will refuse to +allocate those last <tt>s_r_blocks_count</> if the user is not one of the +above. This is done so that the filesystem will usually not be 100% full, +since 100% full filesystems can affect various aspects of operation. + +<tt>s_def_resuid</> and <tt>s_def_resgid</> contain the id of the user and +of the group who can use the reserved blocks in addition to root. + +<sect1>Filesystem current state +<p> + +<tt>s_free_blocks_count</> contains the current number of free blocks +in the filesystem. + +<tt>s_free_inodes_count</> contains the current number of free inodes in the +filesystem. + +<tt>s_mtime</> contains the time at which the system was last mounted. + +<tt>s_wtime</> contains the last time at which something was changed in the +filesystem. + +<sect>Copyright +<p> + +This document contains source code which was taken from the Linux ext2 +kernel source code, mainly from /usr/include/linux/ext2_fs.h. Follows +the original copyright: + +<tscreen><verb> +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +</verb></tscreen> + +<sect>Acknowledgments +<p> + +I would like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: +<itemize> +<item> <tt>Remy Card</> + + Who designed, implemented and maintains the ext2 filesystem kernel + code, and some of the ext2 utilities. <tt>Remy Card</> is also the + author of several helpful slides concerning the ext2 filesystem. + Specifically, he is the author of <tt>File Management in the Linux + Kernel</> and of <tt>The Second Extended File System - Current + State, Future Development</>. + +<item> <tt>Wayne Davison</> + + Who designed the ext2 filesystem. +<item> <tt>Stephen Tweedie</> + + Who helped designing the ext2 filesystem kernel code and wrote the + slides <tt>Optimizations in File Systems</>. +<item> <tt>Theodore Ts'o</> + + Who is the author of several ext2 utilities and of the ext2 library + <tt>libext2fs</> (which I didn't use, simply because I didn't know + it exists when I started to work on my project). +</itemize> + +Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the +<tt>Linux community</> for providing all of us with such a great operating +system. + +Please contact me in a case of an error report, suggestions, or just about +anything concerning this document. + +Enjoy, + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + +Haifa, August 95 +</article> \ No newline at end of file diff --git a/ext2ed/doc/ext2ed-design-0.1.sgml b/ext2ed/doc/ext2ed-design-0.1.sgml new file mode 100644 index 00000000..ba1bd7aa --- /dev/null +++ b/ext2ed/doc/ext2ed-design-0.1.sgml @@ -0,0 +1,2102 @@ +<!doctype linuxdoc system> + +<!-- EXT2ED - Project notes --> +<!-- First written: July 25 1995 --> +<!-- Last updated: August 3 1995 --> +<!-- This document is written Using the Linux documentation project Linuxdoc-SGML DTD --> + +<article> + +<title>EXT2ED - The Extended-2 filesystem editor - Design and implementation +<author>Programmed by Gadi Oxman, with the guide of Avner Lottem +<date>v0.1, August 3 1995 +<toc> + +<!-- Begin of document --> + +<sect>About EXT2ED documentation +<p> + +The EXT2ED documentation consists of three parts: +<itemize> +<item> The ext2 filesystem overview. +<item> The EXT2ED user's guide. +<item> The EXT2ED design and implementation. +</itemize> + +This document is not the user's guide. If you just intend to use EXT2ED, you +may not want to read it. + +However, if you intend to browse and modify the source code, this document is +for you. + +In any case, If you intend to read this article, I strongly suggest that you +will be familiar with the material presented in the other two articles as well. + +<sect>Preface +<p> + +In this document I will try to explain how EXT2ED is constructed. +At this time of writing, the initial version is finished and ready +for distribution; It is fully functional. However, this was not always the +case. + +At first, I didn't know much about Unix, much less about Unix filesystems, +and even less about Linux and the extended-2 filesystem. While working +on this project, I gradually acquired knowledge about all of the above +subjects. I can think of two ways in which I could have made my project: +<enum> +<item> The "Engineer" way + + Learn the subject throughly before I get to the programming itself. + Then, I could easily see the entire picture and select the best + course of action, taking all the factors into account. +<item> The "Explorer - Progressive" way. + + Jump immediately into the cold water - Start programming and + learning the material parallelly. +</enum> + +I guess that the above dilemma is typical and appears all through science and +technology. + +However, I didn't have the luxury of choice when I started my project - +Linux is a relatively new (and great !) operating system. The extended-2 +filesystem is even newer - Its first release lies somewhere in 1993 - Only +passed two years until I started working on my project. + +The situation I found myself at the beginning was that I didn't have a fully +detailed document which describes the ext2 filesystem. In fact, I didn't +have any ext2 document at all. When I asked Avner about documentation, he +suggested two references: +<itemize> +<item> A general Unix book - THE DESIGN OF THE UNIX OPERATING SYSTEM, by + Maurice J. Bach. +<item> The kernel sources. +</itemize> +I read the relevant parts of the book before I started my project - It is a +bit old now, but the principles are still the same. However, I needed +more than just the principles. + +The kernel sources are a rare bonus ! You don't get everyday the full +sources of the operating system. There is so much that can be learned from +them, and it is the ultimate source - The exact answer how the kernel +works is there, with all the fine details. At the first week I started to +look at random at the relevant parts of the sources. However, it is difficult +to understand the global picture from direct reading of over one hundred +page sources. Then, I started to do some programming. I didn't know +yet what I was looking for, and I started to work on the project like a kid +who starts to build a large puzzle. + +However, this was exactly the interesting part ! It is frustrating to know +it all from advance - I think that the discovery itself, bit by bit, is the +key to a true learning and understanding. + +Now, in this document, I am trying to present the subject. Even though I +developed EXT2ED progressively, I now can see the entire subject much +brighter than I did before, and though I do have the option of presenting it +only in the "engineer" way. However, I will not do that. + +My presentation will be mixed - Sometimes I will present a subject with an +incremental perspective, and sometimes from a "top down" view. I'll leave +you to decide if my presentation choice was wise :-) + +In addition, you'll notice that the sections tend to get shorter as we get +closer to the end. The reason is simply that I started to feel that I was +repeating myself so I decided to present only the new ideas. + +<sect>Getting started ... +<p> + +Getting started is almost always the most difficult task. Once you get +started, things start "running" ... + +<sect1>Before the actual programming +<p> + +From mine talking with Avner, I understood that Linux, like any other Unix +system, provides accesses to the entire disk as though it were a general +file - Accessing the device. It is surely a nice idea. Avner suggested two +ways of action: +<itemize> +<item> Opening the device like a regular file in the user space. +<item> Constructing a device driver which will run in the kernel space and + provide hooks for the user space program. The advantage is that it + will be a part of the kernel, and would be able to use the ext2 + kernel functions to do some of the work. +</itemize> +I chose the first way. I think that the basic reason was simplicity - Learning +the ext2 filesystem was complicated enough, and adding to it the task of +learning how to program in the kernel space was too much. I still don't know +how to program a device driver, and this is perhaps the bad part, but +concerning the project in a back-perspective, I think that the first way is +superior to the second; Ironically, because of the very reason I chose it - +Simplicity. EXT2ED can now run entirely in the user space (which I think is +a point in favor, because it doesn't require the user to recompile its +kernel), and the entire hard work is mine, which fitted nicely into the +learning experience - I didn't use other code to do the job (aside from +looking at the sources, of-course). + +<sect1>Jumping into the cold water +<p> + +I didn't know almost anything of the structure of the ext2 filesystem. +Reading the sources was not enough - I needed to experiment. However, a tool +for experiments in the ext2 filesystem was exactly my project ! - Kind of a +paradox. + +I started immediately with constructing a simple <tt>hex editor</> - It would +open the device as a regular file, provide means of moving inside the +filesystem with a simple <tt>offset</> method, and just show a +<tt> hex dump</> of the contents at this point. Programming this was trivially +simple of-course. At this point, the user-interface didn't matter to me - I +wanted a fast way to interact. As a result, I chose a simple command line +parser. Of course, there where no windows at this point. + +A hex editor is nice, but is not enough. It indeed enabled me to see each part +of the filesystem, but the format of the viewed data was difficult to +analyze. I wanted to see the data in a more intuitive way. + +At this point of time, the most helpful file in the sources was the ext2 +main include file - <tt>/usr/include/linux/ext2_fs.h</>. Among its contents +there were various structures which I assumed they are disk images - Appear +exactly like that on the disk. + +I wanted a <tt>quick</> way to get going. I didn't have the patience to learn +each of the structures use in the code. Rather, I wanted to see them in action, +so that I could explore the connections between them - Test my assumptions, +and reach other assumptions. + +So after the <tt>hex editor</>, EXT2ED progressed into a tool which has some +elements of a compiler. I programmed EXT2ED to <tt>dynamically read the kernel +ext2 main include file in run time</>, and process the information. The goal +was to <tt>imply a structure-definition on the current offset at the +filesystem</>. EXT2ED would then display the structure as a list of its +variables names and contents, instead of a meaningless hex dump. + +The format of the include file is not very complicated - The structures +are mostly <tt>flat</> - Didn't contain a lot of recursive structure; Only a +global structure definition, and some variables. There were cases of +structures inside structures, I treated them in a somewhat non-elegant way - I +made all the structures flat, and expanded the arrays. As a result, the parser +was very simple. After all, this was not an exercise in compiling, and I +wanted to quickly get some results. + +To handle the task, I constructed the <tt>struct_descriptor</> structure. +Each <tt>struct_descriptor instance</> contained information which is needed +in order to format a block of data according to the C structure contained in +the kernel source. The information contained: +<itemize> +<item> The descriptor name, used to reference to the structure in EXT2ED. +<item> The name of each variable. +<item> The relative offset of the each variable in the data block. +<item> The length, in bytes, of each variable. +</itemize> +Since I didn't want to limit the number of structures, I chose a simple +double linked list to store the information. One variable contained the +<tt>current structure type</> - A pointer to the relevant +<tt>struct_descriptor</>. + +Now EXT2ED contained basically three command line operations: +<itemize> +<item> setdevice + + Used to open a device for reading only. Write access was postponed + to a very advanced state in the project, simply because I didn't + know a thing of the filesystem structure, and I believed that + making actual changes would do nothing but damage :-) +<item> setoffset + + Used to move in the device. +<item> settype + + Used to imply a structure definition on the current place. +<item> show + + Used to display the data. It displayed the data in a simple hex dump + if there was no type set, or in a nice formatted way - As a list of + the variable contents, if there was. +</itemize> + +Command line analyzing was primitive back then - A simple switch, as far as +I can remember - Nothing alike the current flow control, but it was enough +at the time. + +At the end, I had something to start working with. It knew to format many +structures - None of which I understood - and provided me, without too much +work, something to start with. + +<sect>Starting to explore +<p> + +With the above tool in my pocket, I started to explore the ext2 filesystem +structure. From the brief reading in Bach's book, I got familiar to some +basic concepts - The <tt>superblock</>, for example. It seems that the +superblock is an important part of the filesystem. I decided to start +exploring with that. + +I realized that the superblock should be at a fixed location in the +filesystem - Probably near the beginning. There can be no other way - +The kernel should start at some place to find it. A brief looking in +the kernel sources revealed that the superblock is signed by a special +signature - A <tt>magic number</> - EXT2_SUPER_MAGIC (0xEF53 - EF probably +stands for Extended Filesystem). I quickly found the superblock at the +fixed offset 1024 in the filesystem - The <tt>s_magic</> variable in the +superblock was set exactly to the above value. + +It seems that starting with the <tt>superblock</> was a good bet - Just from +the list of variables, one can learn a lot. I didn't understand all of them +at the time, but it seemed that the following keywords were repeating themself +in various variables: +<itemize> +<item> block +<item> inode +<item> group +</itemize> +At this point, I started to explore the block groups. I will not detail here +the technical design of the ext2 filesystem. I have written a special +article which explains just that, in the "engineering" way. Please refer to it +if you feel that you are lacking knowledge in the structure of the ext2 +filesystem. + +I was exploring the filesystem in this way for some time, along with reading +the sources. This lead naturally to the next step. + +<sect>Object specific commands +<p> + +What has become clear is that the above way of exploring is not powerful +enough - I found myself doing various calculations manually in order to pass +between related structures. I needed to replace some tasks with an automated +procedure. + +In addition, it also became clear that (of-course) each key object in the +filesystem has its special place in regard to the overall ext2 filesystem +design, and needs a <tt>fine tuned handling</>. It is at this point that the +structure definitions <tt>came to life</> - They became <tt>object +definitions</>, making EXT2ED <tt>object oriented</>. + +The actual meaning of the breathtaking words above, is that each structure +now had a list of <tt>private commands</>, which ended up in +<tt>calling special fine-tuned C functions</>. This approach was +found to be very powerful and is <tt>the heart of EXT2ED even now</>. + +In order to implement the above concepts, I added the structure +<tt>struct_commands</>. The role of this structure is to group together a +group of commands, which can be later assigned to a specific type. Each +structure had: +<itemize> +<item> A list of command names. +<item> A list of pointers to functions, which binds each command to its + special fine-tuned C function. +</itemize> +In order to relate a list of commands to a type definition, each +<tt>struct_descriptor</> structure (explained earlier) was added a private +<tt>struct_commands</> structure. + +Follows the current definitions of <tt>struct_descriptor</> and of +<tt>struct_command</>: +<tscreen><code> +struct struct_descriptor { + unsigned long length; + unsigned char name [60]; + unsigned short fields_num; + unsigned char field_names [MAX_FIELDS][80]; + unsigned short field_lengths [MAX_FIELDS]; + unsigned short field_positions [MAX_FIELDS]; + struct struct_commands type_commands; + struct struct_descriptor *prev,*next; +}; + +typedef void (*PF) (char *); + +struct struct_commands { + int last_command; + char *names [MAX_COMMANDS_NUM]; + char *descriptions [MAX_COMMANDS_NUM]; + PF callback [MAX_COMMANDS_NUM]; +}; +</code></tscreen> + +<sect><label id="flow_control">Program flow control +<p> + +Obviously the above approach lead to a major redesign of EXT2ED. The +main engine of the resulting design is basically the same even now. + +I redesigned the program flow control. Up to now, I analyzed the user command +line with the simple switch method. Now I used the far superior callback +method. + +I divided the available user commands into two groups: +<enum> +<item> General commands. +<item> Type specific commands. +</enum> +As a result, at each point in time, the user was able to enter a +<tt>general command</>, selectable from a list of general commands which was +always available, or a <tt>type specific command</>, selectable from a list of +commands which <tt>changed in time</> according to the current type that the +user was editing. The special <tt>type specific command</> "knew" how to +handle the object in the best possible way - It was "fine tuned" for the +object's place in the ext2 filesystem design. + +In order to implement the above idea, I constructed a global variable of +type <tt>struct_commands</>, which contained the <tt>general commands</>. +The <tt>type specific commands</> were accessible through the <tt>struct +descriptors</>, as explained earlier. + +The program flow was now done according to the following algorithm: +<enum> +<item> Ask the user for a command line. +<item> Analyze the user command - Separate it into <tt>command</> and + <tt>arguments</>. +<item> Trace the list of known objects to match the command name to a type. + If the type is found, call the callback function, with the arguments + as a parameter. Then go back to step (1). +<item> If the command is not type specific, try to find it in the general + commands, and call it if found. Go back to step (1). +<item> If the command is not found, issue a short error message, and return + to step (1). +</enum> +Note the <tt>order</> of the above steps. In particular, note that a command +is first assumed to be a type-specific command and only if this fails, a +general command is searched. The "<tt>side-effect</>" (main effect, actually) +is that when we have two commands with the <tt>same name</> - One that is a +type specific command, and one that is a general command, the dispatching +algorithm will call the <tt>type specific command</>. This allows +<tt>overriding</> of a command to provide <tt>fine-tuned</> operation. +For example, the <tt>show</> command is overridden nearly everywhere, +to accommodate for the different ways in which different objects are displayed, +in order to provide an intuitive fine-tuned display. + +The above is done in the <tt>dispatch</> function, in <tt>main.c</>. Since +it is a very important function in EXT2ED, and it is relatively short, I will +list it entirely here. Note that a redesign was made since then - Another +level was added between the two described, but I'll elaborate more on this +later. However, the basic structure follows the explanation described above. +<tscreen><code> +int dispatch (char *command_line) + +{ + int i,found=0; + char command [80]; + + parse_word (command_line,command); + + if (strcmp (command,"quit")==0) return (1); + + /* 1. Search for type specific commands FIRST - Allows overriding of a general command */ + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command && !found;i++) { + if (strcmp (command,current_type->type_commands.names [i])==0) { + (*current_type->type_commands.callback [i]) (command_line); + found=1; + } + } + + /* 2. Now search for ext2 filesystem general commands */ + + if (!found) + for (i=0;i<=ext2_commands.last_command && !found;i++) { + if (strcmp (command,ext2_commands.names [i])==0) { + (*ext2_commands.callback [i]) (command_line); + found=1; + } + } + + + /* 3. If not found, search the general commands */ + + if (!found) + for (i=0;i<=general_commands.last_command && !found;i++) { + if (strcmp (command,general_commands.names [i])==0) { + (*general_commands.callback [i]) (command_line); + found=1; + } + } + + if (!found) { + wprintw (command_win,"Error: Unknown command\n"); + refresh_command_win (); + } + + return (0); +} +</code></tscreen> + +<sect>Source files in EXT2ED +<p> + +The project was getting large enough to be splitted into several source +files. I splitted the source as much as I could into self-contained +source files. The source files consist of the following blocks: +<itemize> +<item> <tt>Main include file - ext2ed.h</> + + This file contains the definitions of the various structures, + variables and functions used in EXT2ED. It is included by all source + files in EXT2ED. + +<item> <tt>Main block - main.c</> + + <tt>main.c</> handles the upper level of the program flow control. + It contains the <tt>parser</> and the <tt>dispatcher</>. Its task is + to ask the user for a required action, and to pass control to other + lower level functions in order to do the actual job. + +<item> <tt>Initialization - init.c</> + + The init source is responsible for the various initialization + actions which need to be done through the program. For example, + auto detection of an ext2 filesystem when selecting a device and + initialization of the filesystem-specific structures described + earlier. + +<item> <tt>Disk activity - disk.c</> + + <tt>disk.c</> is handles the lower level interaction with the + device. All disk activity is passed through this file - The various + functions through the source code request disk actions from the + functions in this file. In this way, for example, we can easily block + the write access to the device. + +<item> <tt>Display output activity - win.c</> + + In a similar way to <tt>disk.c</>, the user-interface functions and + most of the interaction with the <tt>ncurses library</> are done + here. Nothing will be actually written to a specific window without + calling a function from this file. + +<item> <tt>Commands available through dispatching - *_com.c </> + + The above file name is generic - Each file which ends with + <tt>_com.c</> contains a group of related commands which can be + called through <tt>the dispatching function</>. + + Each object typically has its own file. A separate file is also + available for the general commands. +</itemize> +The entire list of source files available at this time is: +<itemize> +<item> blockbitmap_com.c +<item> dir_com.c +<item> disk.c +<item> ext2_com.c +<item> file_com.c +<item> general_com.c +<item> group_com.c +<item> init.c +<item> inode_com.c +<item> inodebitmap_com.c +<item> main.c +<item> super_com.c +<item> win.c +</itemize> + +<sect>User interface +<p> + +The user interface is text-based only and is based on the following +libraries: + +<itemize> +<item> The <tt>ncurses</> library, developed by <tt>Zeyd Ben-Halim</>. +<item> The <tt>GNU readline</> library. +</itemize> + +The user interaction is command line based - The user enters a command +line, which consists of a <tt>command</> and of <tt>arguments</>. This fits +nicely with the program flow control described earlier - The <tt>command</> +is used by <tt>dispatch</> to select the right function, and the +<tt>arguments</> are interpreted by the function itself. + +<sect1>The ncurses library +<p> + +The <tt>ncurses</> library enables me to divide the screen into "windows". +The main advantage is that I treat the "window" in a virtual way, asking +the ncurses library to "write to a window". However, the ncurses +library internally buffers the requests, and nothing is actually passed to the +terminal until an explicit refresh is requested. When the refresh request is +made, ncurses compares the current terminal state (as known in the last time +that a refresh was done) with the new to be shown state, and passes to the +terminal the minimal information required to update the display. As a +result, the display output is optimized behind the scenes by the +<tt>ncurses</> library, while I can still treat it in a virtual way. + +There are two basic concepts in the <tt>ncurses</> library: +<itemize> +<item> A window. +<item> A pad. +</itemize> +A window can be no bigger than the actual terminal size. A pad, however, is +not limited in its size. + +The user screen is divided by EXT2ED into three windows and one pad: +<itemize> +<item> Title window. +<item> Status window. +<item> Main display pad. +<item> Command window. +</itemize> + +The <tt>title window</> is static - It just displays the current version +of EXT2ED. + +The user interaction is done in the <tt>command window</>. The user enters a +<tt>command line</>, feedback is usually displayed there, and then relevant +data is usually displayed in the main display and in the status window. + +The <tt>main display</> is using a <tt>pad</> instead of a window because +the amount of information which is written to it is not known in advance. +Therefor, the user treats the main display as a "window" into a bigger +display and can <tt>scroll vertically</> using the <tt>pgdn</> and <tt>pgup</> +commands. Although the <tt>pad</> mechanism enables me to use horizontal +scrolling, I have not utilized this. + +When I need to show something to the user, I use the ncurses <tt>wprintw</> +command. Then an explicit refresh command is required. As explained before, +the refresh commands is piped through <tt>win.c</>. For example, to update +the command window, <tt>refresh_command_win ()</> is used. + +<sect1>The readline library +<p> + +Avner suggested me to integrate the GNU <tt>readline</> library in my project. +The <tt>readline</> library is designed specifically for programs which use +command line interface. It provides a nice package of <tt>command line editing +tools</> - Inserting, deleting words, and the whole package of editing tools +which are normally available in the <tt>bash</> shell (Refer to the readline +documentation for details). In addition, I utilized the <tt>history</> +feature of the readline library - The entered commands are saved in a +<tt>command history</>, and can be called later by whatever means that the +readline package provides. Command completion is also supported - When the +user enters a partial command name, EXT2ED will provide the readline library +with the possible completions. + +<sect>Possible support of other filesystems +<p> + +The entire ext2 layer is provided through specific objects. Given another +set of objects, support of other filesystem can be provided using the same +dispatching mechanism. In order to prepare the surface for this option, I +added yet another layer to the two-layer structure presented earlier. EXT2ED +commands now consist of three layers: +<itemize> +<item> The general commands. +<item> The ext2 general commands. +<item> The ext2 object specific commands. +</itemize> +The general commands are provided by the <tt>general_com.c</> source file, +and are always available. The two other levels are not present when EXT2ED +loads - They are dynamically added by <tt>init.c</> when EXT2ED detects an +ext2 filesystem on the device. + +The abstraction levels presented above helps to extend EXT2ED to fully +support a new filesystem, with its own specific type commands. + +Even without any source code modification, the user is free to add structure +definitions in a separate file (specified in the configuration file), +which will be added to the list of available objects. The added objects will +consist only of variables, of-course, and will be used through the more +primitive <tt>setoffset</> and <tt>settype</> commands. + +<sect>On the implementation of the various commands +<p> + +This section points out some typical programming style that I used in many +places at the code. + +<sect1>The explicit use of the dispatch function +<p> + +The various commands are reached by the user through the <tt>dispatch</> +function. This is not surprising. The fact that can be surprising, at least in +a first look, is that <tt>you'll find the <em>dispatch</> call in many of my +own functions !</>. + +I am in fact using my own implemented functions to construct higher +level operations. I am heavily using the fact that the dispatching mechanism +is object oriented ant that the <tt>overriding</> principle takes place and +selects the proper function to call when several commands with the same name +are accessible. + +Sometimes, however, I call the explicit command directly, without passing +through <tt>dispatch</>. This is typically done when I want to bypass the +<tt>overriding</> effect. + +<tscreen><verb> +This is used, for example, in the interaction between the global cd command +and the dir object specific cd command. You will see there that in order +to implement the "entire" cd command, the type specific cd command uses both +a dispatching mechanism to call itself recursively if a relative path is +used, or a direct call of the general cd handling function if an explicit path +is used. +</verb></tscreen> + +<sect1>Passing information between handling functions +<p> + +Typically, every source code file which handles one object type has a global +structure specifically designed for it which is used by most of the +functions in that file. This is used to pass information between the various +functions there, and to physically provide the link to other related +objects, typically for initialization use. + +<tscreen><verb> +For example, in order to edit a file, information about the +inode is needed - The file command is available only when editing an +inode. When the file command is issued, the handling function (found, +according to the source division outlined above, in inode_com.c) will +store the necessary information about the inode in a specific structure +of type struct_file_info which will be available for use by the file_com.c +functions. Only then it will set the type to file. This is also the reason +that a direct asynchronic set of the object type to a file through a settype +command will fail - The above data structure will not be initialized +properly because the user never was at the inode of the file. +</verb></tscreen> + +<sect1>A very simplified overview of a typical command handling function +<p> + +This is a very simplified overview. Detailed information will follow +where appropriate. + +<sect2>The prototype of a typical handling function +<p> + +<enum> +<item> I chose a unified <tt>naming convention</> for the various object + specific commands. It is perhaps best showed with an example: + + The prototype of the handling function of the command <tt>next</> of + the type <tt>file</> is: + <tscreen><verb> + extern void type_file___next (char *command_line); + </verb></tscreen> + + For other types and commands, the words <tt>file</> and <tt>next</> + should be replaced accordingly. + +<item> The ext2 general commands syntax is similar. For example, the ext2 + general command <tt>super</> results in calling: + <tscreen><verb> + extern void type_ext2___super (char *command_line); + </verb></tscreen> + Those functions are available in <tt>ext2_com.c</>. +<item> The general commands syntax is even simpler - The name of the + handling function is exactly the name of the commands. Those + functions are available in <tt>general_com.c</>. +</enum> + +<sect2> "Typical" algorithm +<p> + +This section can't of-course provide meaningful information - Each +command is handled differently, but the following frame is typical: +<enum> +<item> Parse command line arguments and analyze them. Return with an error + message if the syntax is wrong. +<item> "Act accordingly", perhaps making use of the global variable available + to this type. +<item> Use some <tt>dispatch / direct </> calls in order to pass control to + other lower-level user commands. +<item> Sometimes <tt>dispatch</> to the object's <tt>show</> command to + display the resulting data to the user. +</enum> +I told you it is meaningless :-) + +<sect>Initialization overview +<p> + +In this section I will discuss some aspects of the various initialization +routines available in the source file <tt>init.c</>. + +<sect1>Upon startup +<p> + +Follows the function <tt>main</>, appearing of-course in <tt>main.c</>: +<tscreen><code> +int main (void) + +{ + if (!init ()) return (0); /* Perform some initial initialization */ + /* Quit if failed */ + + parser (); /* Get and parse user commands */ + + prepare_to_close (); /* Do some cleanup */ + printf ("Quitting ...\n"); + return (1); /* And quit */ +} +</code></tscreen> + +The two initialization functions, which are called by <tt>main</>, are: +<itemize> +<item> init +<item> prepare_to_close +</itemize> + +<sect2>The init function +<p> + +<tt>init</> is called from <tt>main</> upon startup. It initializes the +following tasks / subsystems: +<enum> +<item> Processing of the <tt>user configuration file</>, by using the + <tt>process_configuration_file</> function. Failing to complete the + configuration file processing is considered a <tt>fatal error</>, + and EXT2ED is aborted. I did it this way because the configuration + file has some sensitive user options like write access behavior, and + I wanted to be sure that the user is aware of them. +<item> Registration of the <tt>general commands</> through the use of + the <tt>add_general_commands</> function. +<item> Reset of the object memory rotating lifo structure. +<item> Reset of the device parameters and of the current type. +<item> Initialization of the windows subsystem - The interface between the + ncurses library and EXT2ED, through the use of the <tt>init_windows</> + function, available in <tt>win.c</>. +<item> Initialization of the interface between the readline library and + EXT2ED, through <tt>init_readline</>. +<item> Initialization of the <tt>signals</> subsystem, through + <tt>init_signals</>. +<item> Disabling write access. Write access needs to be explicitly enabled + using a user command, to prevent accidental user mistakes. +</enum> +When <tt>init</> is finished, it dispatches the <tt>help</> command in order +to show the available commands to the user. Note that the ext2 layer is still +not added; It will be added if and when EXT2ED will detect an ext2 +filesystem on a device. + +<sect2>The prepare_to_close function +<p> + +The <tt>prepare_to_close</> function reverses some of the actions done +earlier in EXT2ED and freeing the dynamically allocated memory. +Specifically, it: +<enum> +<item> Closes the open device, if any. +<item> Removes the first level - Removing the general commands, through + the use of <tt>free_user_commands</>, with a pointer to the + general_commands structure as a parameter. +<item> Removes of the second level - Removing the ext2 ext2 general + commands, in much the same way. +<item> Removes of the third level - Removing the objects and the object + specific commands, by using <tt>free_struct_descriptors</>. +<item> Closes the window subsystem, and deattaches EXT2ED from the ncurses + library, through the use of the <tt>close_windows</> function, + available in <tt>win.c</>. +</enum> + +<sect1> Registration of commands +<p> + +Addition of a user command is done through the <tt>add_user_command</> +function. The prototype is: +<tscreen><verb> +void add_user_command (struct struct_commands *ptr,char *name,char +*description,PF callback); +</verb></tscreen> +The function receives a pointer to a structure of type +<tt>struct_commands</>, a desired name for the command which will be used by +the user to identify the command, a short description which is utilized by the +<tt>help</> subsystem, and a pointer to a C function which will be called if +<tt>dispatch</> decides that this command was requested. + +The <tt>add_user_command</> is a <tt>low level function</> used in the three +levels to add user commands. For example, addition of the <tt>ext2 +general commands is done by:</> +<tscreen><code> +void add_ext2_general_commands (void) + +{ + add_user_command (&ero;ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super); + add_user_command (&ero;ext2_commands,"group","Moves to the first group descriptor",type_ext2___group); + add_user_command (&ero;ext2_commands,"cd","Moves to the directory specified",type_ext2___cd); +} +</code></tscreen> + +<sect1>Registration of objects +<p> + +Registration of objects is based, as explained earlier, on the "compilation" +of an external user file, which has a syntax similar to the C language +<tt>struct</> keyword. The primitive parser I have implemented detects the +definition of structures, and calls some lower level functions to actually +register the new detected object. The parser's prototype is: +<tscreen><verb> +int set_struct_descriptors (char *file_name) +</verb></tscreen> +It opens the given file name, and calls, when appropriate: +<itemize> +<item> add_new_descriptor +<item> add_new_variable +</itemize> +<tt>add_new_descriptor</> is a low level function which adds a new descriptor +to the doubly linked list of the available objects. It will then call +<tt>fill_type_commands</>, which will add specific commands to the object, +if the object is known. + +<tt>add_new_variable</> will add a new variable of the requested length to the +specified descriptor. + +<sect1>Initialization upon specification of a device +<p> + +When the general command <tt>setdevice</> is used to open a device, some +initialization sequence takes place, which is intended to determine two +factors: +<itemize> +<item> Are we dealing with an ext2 filesystem ? +<item> What are the basic filesystem parameters, such as its total size and + its block size ? +</itemize> +This questions are answered by the <tt>set_file_system_info</>, possibly +using some <tt>help from the user</>, through the configuration file. +The answers are placed in the <tt>file_system_info</> structure, which is of +type <tt>struct_file_system_info</>: +<tscreen><code> +struct struct_file_system_info { + unsigned long file_system_size; + unsigned long super_block_offset; + unsigned long first_group_desc_offset; + unsigned long groups_count; + unsigned long inodes_per_block; + unsigned long blocks_per_group; /* The name is misleading; beware */ + unsigned long no_blocks_in_group; + unsigned short block_size; + struct ext2_super_block super_block; +}; +</code></tscreen> + +Autodetection of an ext2 filesystem is usually recommended. However, on a damaged +filesystem I can't assure a success. That's were the user comes in - He can +<tt>override</> the auto detection procedure and force an ext2 filesystem, by +selecting the proper options in the configuration file. + +If auto detection succeeds, the second question above is automatically +answered - I get all the information I need from the filesystem itself. In +any case, default parameters can be supplied in the configuration file and +the user can select the required behavior. + +If we decide to treat the filesystem as an ext2 filesystem, <tt>registration of +the ext2 specific objects</> is done at this point, by calling the +<tt>set_struct_descriptors</> outlined earlier, with the name of the file +which describes the ext2 objects, and is basically based on the ext2 sources +main include file. At this point, EXT2ED can be fully used by the user. + +If we do not register the ext2 specific objects, the user can still provide +object definitions in a separate file, and will be able to use EXT2ED in a +<tt>limited form</>, but more sophisticated than a simple hex editor. + +<sect>main.c +<p> + +As described earlier, <tt>main.c</> is used as a front-head to the entire +program. <tt>main.c</> contains the following elements: + +<sect1>The main routine +<p> + +The <tt>main</> routine was displayed above. Its task is to pass control to +the initialization routines and to the parser. + +<sect1>The parser +<p> + +The parser consists of the following functions: +<itemize> +<item> The <tt>parser</> function, which reads the command line from the + user and saves it in readline's history buffer and in the internal + last-command buffer. +<item> The <tt>parse_word</> function, which receives a string and parses + the first word from it, ignoring whitespaces, and returns a pointer + to the rest of the string. +<item> The <tt>complete_command</> function, which is used by the readline + library for command completion. It scans the available commands at + this point and determines the possible completions. +</itemize> + +<sect1>The dispatcher +<p> + +The dispatcher was already explained in the flow control section - section +<ref id="flow_control">. Its task is to pass control to the proper command +handling function, based on the command line's command. + +<sect1>The self-sanity control +<p> + +This is not fully implemented. + +The general idea was to provide a control system which will supervise the +internal work of EXT2ED. Since I am pretty sure that bugs exist, I have +double checked myself in a few instances, and issued an <tt>internal +error</> warning if I reached the conclusion that something is not logical. +The internal error is reported by the function <tt>internal_error</>, +available in <tt>main.c</>. + +The self sanity check is compiled only if the compile time option +<tt>DEBUG</> is selected. + +<sect>The windows interface +<p> + +Screen handling and interfacing to the <tt>ncurses</> library is done in +<tt>win.c</>. + +<sect1>Initialization +<p> + +Opening of the windows is done in <tt>init_windows</>. In +<tt>close_windows</>, we just close our windows. The various window lengths +with an exception to the <tt>show pad</> are defined in the main header file. +The rest of the display will be used by the <tt>show pad</>. + +<sect1>Display output +<p> + +Each actual refreshing of the terminal monitor is done by using the +appropriate refresh function from this file: <tt>refresh_title_win</>, +<tt>refresh_show_win</>, <tt>refresh_show_pad</> and +<tt>refresh_command_win</>. + +With the exception of the <tt>show pad</>, each function simply calls the +<tt>ncurses refresh command</>. In order to provide to <tt>scrolling</> in +the <tt>show pad</>, some information about its status is constantly updated +by the various functions which display output in it. <tt>refresh_show_pad</> +passes this information to <tt>ncurses</> so that the correct part of the pad +is actually copied to the display. + +The above information is saved in a global variable of type <tt>struct +struct_pad_info</>: + +<tscreen><code> +struct struct_pad_info { + int display_lines,display_cols; + int line,col; + int max_line,max_col; + int disable_output; +}; +</code></tscreen> + +<sect1>Screen redraw +<p> + +The <tt>redraw_all</> function will just reopen the windows. This action is +necessary if the display gets garbled from some reason. + +<sect>The disk interface +<p> + +All the disk activity with regard to the filesystem passes through the file +<tt>disk.c</>. This is done that way to provide additional levels of safety +concerning the disk access. This way, global decisions considering the disk +can be easily accomplished. The benefits of this isolation will become even +clearer in the next sections. + +<sect1>Low level functions +<p> + +Read requests are ultimately handled by <tt>low_read</> and write requests +are handled by <tt>low_write</>. They just receive the length of the data +block, the offset in the filesystem and a pointer to the buffer and pass the +request to the <tt>fread</> or <tt>fwrite</> standard library functions. + +<sect1>Mounted filesystems +<p> + +EXT2ED design assumes that the edited filesystem is not mounted. Even if +a <tt>reasonably simple</> way to handle mounted filesystems exists, it is +probably <tt>too complicated</> :-) + +Write access to a mounted filesystem will be denied. Read access can be +allowed by using a configuration file option. The mount status is determined +by reading the file /etc/mtab. + +<sect1>Write access +<p> + +Write access is the most sensitive part in the program. This program is +intended for <tt>editing filesystems</>. It is obvious that a small mistake +in this regard can make the filesystem not usable anymore. + +The following safety measures are added, of-course, to the general Unix +permission protection - The user can always disable write access on the +device file itself. + +Considering the user, the following safety measures were taken: +<enum> +<item> The filesystem is <tt>never</> opened with write-access enables. + Rather, the user must explicitly request to enable write-access. +<item> The user can <tt>disable</> write access entirely by using a + <tt>configuration file option</>. +<item> Changes are never done automatically - Whenever the user makes + changes, they are done in memory. An explicit <tt>writedata</> + command should be issued to make the changes active in the disk. +</enum> +Considering myself, I tried to protect against my bugs by: +<itemize> +<item> Opening the device in read-only mode until a write request is + issued by the user. +<item> Limiting <tt>actual</> filesystem access to two functions only - + <tt>low_read</> for reading, and <tt>low_write</> for writing. Those + functions were programmed carefully, and I added the self + sanity checks there. In addition, this is the only place in which I + need to check the user options described above - There can be no + place in which I can "forget" to check them. + + Note that The disabling of write-access through the configuration file + is double checked here only as a <tt>self-sanity</> check - If + <tt>DEBUG</> is selected, since write enable should have been refused + and write-access is always disabled at startup, hence finding + <tt>here</> that the user has write access disabled through the + configuration file clearly indicates that I have a bug somewhere. +</itemize> + +The following safety measure can provide protection against <tt>both</> user +mistakes and my own bugs: +<itemize> +<item> I added a <tt>logging option</>, which logs every actual write + access to the disk in the lowest level - In <tt>low_write</> itself. + + The logging has nothing to do with the current type and the various + other higher level operations of EXT2ED - It is simply a hex dump of + the contents which will be overwritten; Both the original contents + and the new written data. + + In that case, even if the user makes a mistake, the original data + can be retrieved. + + Even If I have a bug somewhere which causes incorrect data to be + written to the disk, the logging option will still log exactly the + original contents at the place were data was incorrectly overwritten. + (This assumes, of-course, that <tt>low-write</> and the <tt>logging + itself</> work correctly. I have done my best to verify that this is + indeed the case). + + The <tt>logging</> option is implemented in the <tt>log_changes</> + function. +</itemize> + +<sect1>Reading / Writing objects +<p> + +Usually <tt>(not always)</>, the current object data is available in the +global variable <tt>type_data</>, which is of the type: +<tscreen><code> +struct struct_type_data { + long offset_in_block; + + union union_type_data { + char buffer [EXT2_MAX_BLOCK_SIZE]; + struct ext2_acl_header t_ext2_acl_header; + struct ext2_acl_entry t_ext2_acl_entry; + struct ext2_old_group_desc t_ext2_old_group_desc; + struct ext2_group_desc t_ext2_group_desc; + struct ext2_inode t_ext2_inode; + struct ext2_super_block t_ext2_super_block; + struct ext2_dir_entry t_ext2_dir_entry; + } u; +}; +</code></tscreen> +The above union enables me, in the program, to treat the data as raw data or +as a meaningful filesystem object. + +The reading and writing, if done to this global variable, are done through +the functions <tt>load_type_data</> and <tt>write_type_data</>, available in +<tt>disk.c</>. + +<sect>The general commands +<p> + +The <tt>general commands</> are handled in the file <tt>general_com.c</>. + +<sect1>The help system +<p> + +The help command is handled by the function <tt>help</>. The algorithm is as +follows: + +<enum> +<item> Check the command line arguments. If there is an argument, pass + control to the <tt>detailed_help</> function, in order to provide + help on the specific command. +<item> If general help was requested, display a list of the available + commands at this point. The three levels are displayed in reverse + order - First the commands which are specific to the current type + (If a current type is defined), then the ext2 general commands (If + we decided that the filesystem should be treated like an ext2 + filesystem), then the general commands. +<item> Display information about EXT2ED - Current version, general + information about the project, etc. +</enum> + +<sect1>The setdevice command +<p> + +The <tt>setdevice</> commands result in calling the <tt>set_device</> +function. The algorithm is: + +<enum> +<item> Parse the command line argument. If it isn't available report the + error and return. +<item> Close the current open device, if there is one. +<item> Open the new device in read-only mode. Update the global variables + <tt>device_name</> and <tt>device_handle</>. +<item> Disable write access. +<item> Empty the object memory. +<item> Unregister the ext2 general commands, using + <tt>free_user_commands</>. +<item> Unregister the current objects, using <tt>free_struct_descriptors</> +<item> Call <tt>set_file_system_info</> to auto-detect an ext2 filesystem + and set the basic filesystem values. +<item> Add the <tt>alternate descriptors</>, supplied by the user. +<item> Set the device offset to the filesystem start by dispatching + <tt>setoffset 0</>. +<item> Show the new available commands by dispatching the <tt>help</> + command. +</enum> + +<sect1>Basic maneuvering +<p> + +Basic maneuvering is done using the <tt>setoffset</> and the <tt>settype</> +user commands. + +<tt>set_offset</> accepts some alternative forms of specifying the new +offset. They all ultimately lead to changing the <tt>device_offset</> +global variable and seeking to the new position. <tt>set_offset</> also +calls <tt>load_type_data</> to read a block ahead of the new position into +the <tt>type_data</> global variable. + +<tt>set_type</> will point the global variable <tt>current_type</> to the +correct entry in the double linked list of the known objects. If the +requested type is <tt>hex</> or <tt>none</>, <tt>current_type</> will be +initialized to <tt>NULL</>. <tt>set_type</> will also dispatch <tt>show</>, +so that the object data will be re-formatted in the new format. + +When editing an ext2 filesystem, it is not intended that those commands will +be used directly, and it is usually not required. My implementation of the +ext2 layer, on the other hand, uses this lower level commands on countless +occasions. + +<sect1>The display functions +<p> + +The general command version of <tt>show</> is handled by the <tt>show</> +function. This command is overridden by various objects to provide a display +which is better suited to the object. + +The general show command will format the data in <tt>type_data</> according +to the structure definition of the current type and show it on the <tt>show +pad</>. If there is no current type, the data will be shown as a simple hex +dump; Otherwise, the list of variables, along with their values will be shown. + +A call to <tt>show_info</> is also made - <tt>show_info</> will provide +<tt>general statistics</> on the <tt>show_window</>, such as the current +block, current type, current offset and current page. + +The <tt>pgup</> and <tt>pgdn</> general commands just update the +<tt>show_pad_info</> global variable - We just increment +<tt>show_pad_info.line</> with the number of lines in the screen - +<tt>show_pad_info.display_lines</>, which was initialized in +<tt>init_windows</>. + +<sect1>Changing data +<p> + +Data change is done in memory only. An update to the disk if followed by an +explicit <tt>writedata</> command to the disk. The <tt>write_data</> +function simple calls the <tt>write_type_data</> function, outlined earlier. + +The <tt>set</> command is used for changing the data. + +If there is no current type, control is passed to the <tt>hex_set</> function, +which treats the data as a block of bytes and uses the +<tt>type_data.offset_in_block</> variable to write the new text or hex string +to the correct place in the block. + +If a current type is defined, the requested variable is searched in the +current object, and the desired new valued is entered. + +The <tt>enablewrite</> commands just sets the global variable +<tt>write_access</> to <tt>1</> and re-opens the filesystem in read-write +mode, if possible. + +If the current type is NULL, a hex-mode is assumed - The <tt>next</> and +<tt>prev</> commands will just update <tt>type_data.offset_in_block</>. + +If the current type is not NULL, the The <tt>next</> and <tt>prev</> command +are usually overridden anyway. If they are not overridden, it will be assumed +that the user is editing an array of such objects, and they will just pass +to the next / prev element by dispatching to <tt>setoffset</> using the +<tt>setoffset type + / - X</> syntax. + +<sect>The ext2 general commands +<p> + +The ext2 general commands are contained in the <tt>ext2_general_commands</> +global variable (which is of type <tt>struct struct_commands</>). + +The handling functions are implemented in the source file <tt>ext2_com.c</>. +I will include the entire source code since it is relatively short. + +<sect1>The super command +<p> + +The super command just "brings the user" to the main superblock and set the +type to ext2_super_block. The implementation is trivial: + +<tscreen><code> +void type_ext2___super (char *command_line) + +{ + char buffer [80]; + + super_info.copy_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_super_block");dispatch (buffer); +} +</code></tscreen> +It involves only setting the <tt>copy_num</> variable to indicate the main +copy, dispatching a <tt>setoffset</> command to reach the superblock, and +dispatching a <tt>settype</> to enable the superblock specific commands. +This last command will also call the <tt>show</> command of the +<tt>ext2_super_block</> type, through dispatching at the general command +<tt>settype</>. + +<sect1>The group command +<p> + +The group command will bring the user to the specified group descriptor in +the main copy of the group descriptors. The type will be set to +<tt>ext2_group_desc</>: +<tscreen><code> +void type_ext2___group (char *command_line) + +{ + long group_num=0; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + group_num=atol (buffer); + } + + group_info.copy_num=0;group_info.group_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); + sprintf (buffer,"entry %ld",group_num);dispatch (buffer); +} +</code></tscreen> +The implementation is as trivial as the <tt>super</> implementation. Note +the use of the <tt>entry</> command, which is a command of the +<tt>ext2_group_desc</> object, to pass to the correct group descriptor. + +<sect1>The cd command +<p> + +The <tt>cd</> command performs the usual cd function. The path to the global +cd command is a path from <tt>/</>. + +<tt>This is one of the best examples of the power of the object oriented +design and of the dispatching mechanism. The operation is complicated, yet the +implementation is surprisingly short !</> + +<tscreen><code> +void type_ext2___cd (char *command_line) + +{ + char temp [80],buffer [80],*ptr; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n"); + refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + if (buffer [0] != '/') { + wprintw (command_win,"Error - Use a full pathname (begin with '/')\n"); + refresh_command_win ();return; + } + + dispatch ("super");dispatch ("group");dispatch ("inode"); + dispatch ("next");dispatch ("dir"); + if (buffer [1] != 0) { + sprintf (temp,"cd %s",buffer+1);dispatch (temp); + } +} +</code></tscreen> + +Note the number of the dispatch calls ! + +<tt>super</> is used to get to the superblock. <tt>group</> to get to the +first group descriptor. <tt>inode</> brings us to the first inode - The bad +blocks inode. A <tt>next</> is command to pass to the root directory inode, +a <tt>dir</> command "enters" the directory, and then we let the <tt>object +specific cd command</> to take us from there (The object is <tt>dir</>, so +that <tt>dispatch</> will call the <tt>cd</> command of the <tt>dir</> type). +Note that a symbolic link following could bring us back to the root directory, +thus the innocent calls above treats nicely such a recursive case ! + +I feel that the above is <tt>intuitive</> - I was expressing myself "in the +language" of the ext2 filesystem - (Go to the inode, etc), and the code was +written exactly in this spirit ! + +I can write more at this point, but I guess I am already a bit carried +away with the self compliments :-) + +<sect>The superblock +<p> + +This section details the handling of the superblock. + +<sect1>The superblock variables +<p> + +The superblock object is <tt>ext2_super_block</>. The definition is just +taken from the kernel ext2 main include file - /usr/include/linux/ext2_fs.h. +<footnote> +Those lines of source are copyrighted by <tt>Remy Card</> - The author of the +ext2 filesystem, and by <tt>Linus Torvalds</> - The first author of the Linux +operating system. Please cross reference the section Acknowledgments for the +full copyright. +</footnote> +<tscreen><code> +struct ext2_super_block { + __u32 s_inodes_count; /* Inodes count */ + __u32 s_blocks_count; /* Blocks count */ + __u32 s_r_blocks_count; /* Reserved blocks count */ + __u32 s_free_blocks_count; /* Free blocks count */ + __u32 s_free_inodes_count; /* Free inodes count */ + __u32 s_first_data_block; /* First Data Block */ + __u32 s_log_block_size; /* Block size */ + __s32 s_log_frag_size; /* Fragment size */ + __u32 s_blocks_per_group; /* # Blocks per group */ + __u32 s_frags_per_group; /* # Fragments per group */ + __u32 s_inodes_per_group; /* # Inodes per group */ + __u32 s_mtime; /* Mount time */ + __u32 s_wtime; /* Write time */ + __u16 s_mnt_count; /* Mount count */ + __s16 s_max_mnt_count; /* Maximal mount count */ + __u16 s_magic; /* Magic signature */ + __u16 s_state; /* File system state */ + __u16 s_errors; /* Behavior when detecting errors */ + __u16 s_pad; + __u32 s_lastcheck; /* time of last check */ + __u32 s_checkinterval; /* max. time between checks */ + __u32 s_creator_os; /* OS */ + __u32 s_rev_level; /* Revision level */ + __u16 s_def_resuid; /* Default uid for reserved blocks */ + __u16 s_def_resgid; /* Default gid for reserved blocks */ + __u32 s_reserved[0]; /* Padding to the end of the block */ + __u32 s_reserved[1]; /* Padding to the end of the block */ + . + . + . + __u32 s_reserved[234]; /* Padding to the end of the block */ +}; +</code></tscreen> + +Note that I <tt>expanded</> the array due to my primitive parser +implementation. The various fields are described in the <tt>technical +document</>. + +<sect1>The superblock commands +<p> + +This section explains the commands available in the <tt>ext2_super_block</> +type. They all appear in <tt>super_com.c</> + +<sect2>The show command +<p> + +The <tt>show</> command is overridden here in order to provide more +information than just the list of variables. A <tt>show</> command will end +up in calling <tt>type_super_block___show</>. + +The first thing that we do is calling the <tt>general show command</> in +order to display the list of variables. + +We then add some interpretation to the various lines to make the data +somewhat more intuitive (Expansion of the time variables and the creator +operating system code, for example). + +We also display the <tt>backup copy number</> of the superblock in the status +window. This copy number is saved in the <tt>super_info</> global variable - +<tt>super_info.copy_num</>. Currently, this is the only variable there ... +but this type of internal variable saving is typical through my +implementation. + +<sect2>The backup copies handling commands +<p> + +The <tt>current copy number</> is available in <tt>super_info.copy_num</>. It +was initialized in the ext2 command <tt>super</>, and is used by the various +superblock routines. + +The <tt>gocopy</> routine will pass to another copy of the superblock. The +new device offset will be computed with the aid of the variables in the +<tt>file_system_info</> structure. Then the routine will <tt>dispatch</> to +the <tt>setoffset</> and the <tt>show</> routines. + +The <tt>setactivecopy</> routine will just save the current superblock data +in a temporary variable of type <tt>ext2_super_block</>, and will dispatch +<tt>gocopy 0</> to pass to the main superblock. Then it will place the saved +data in place of the actual data. + +The above two commands can be used if the main superblock is corrupted. + +<sect>The group descriptors +<p> + +The group descriptors handling mechanism allows the user to take a tour in +the group descriptors table, stopping at each point, and examining the +relevant inode table, block allocation map or inode allocation map through +dispatching to the relevant objects. + +Some information about the group descriptors is available in the global +variable <tt>group_info</>, which is of type <tt>struct_group_info</>: + +<tscreen><code> +struct struct_group_info { + unsigned long copy_num; + unsigned long group_num; +}; +</code></tscreen> + +<tt>group_num</> is the index of the current descriptor in the table. + +<tt>copy_num</> is the number of the current backup copy. + +<sect1>The group descriptor's variables +<p> + +<tscreen><code> +struct ext2_group_desc +{ + __u32 bg_block_bitmap; /* Blocks bitmap block */ + __u32 bg_inode_bitmap; /* Inodes bitmap block */ + __u32 bg_inode_table; /* Inodes table block */ + __u16 bg_free_blocks_count; /* Free blocks count */ + __u16 bg_free_inodes_count; /* Free inodes count */ + __u16 bg_used_dirs_count; /* Directories count */ + __u16 bg_pad; + __u32 bg_reserved[3]; +}; +</code></tscreen> + +The first three variables are used to provide the links to the +<tt>blockbitmap, inodebitmap and inode</> objects. + +<sect1>Movement in the table +<p> + +Movement in the group descriptors table is done using the <tt>next, prev and +entry</> commands. Note that the first two commands <tt>override</> the +general commands of the same name. The <tt>next and prev</> command are just +calling the <tt>entry</> function to do the job. I will show <tt>next</>, +for example: + +<tscreen><code> +void type_ext2_group_desc___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num+entry_offset); + dispatch (buffer); +} +</code></tscreen> +The <tt>entry</> function is also simple - It just calculates the offset +using the information in <tt>group_info</> and in <tt>file_system_info</>, +and uses the usual <tt>setoffset / show</> pair. + +<sect1>The show command +<p> + +As usual, the <tt>show</> command is overridden. The implementation is +similar to the superblock's show implementation - We just call the general +show command, and add some information in the status window - The contents of +the <tt>group_info</> structure. + +<sect1>Moving between backup copies +<p> + +This is done exactly like the superblock case. Please refer to explanation +there. + +<sect1>Links to the available friends +<p> + +From a group descriptor, one typically wants to reach an <tt>inode</>, or +one of the <tt>allocation bitmaps</>. This is done using the <tt>inode, +blockbitmap or inodebitmap</> commands. The implementation is again trivial +- Get the necessary information from the group descriptor, initialize the +structures of the next type, and issue the <tt>setoffset / settype</> pair. + +For example, here is the implementation of the <tt>blockbitmap</> command: + +<tscreen><code> +void type_ext2_group_desc___blockbitmap (char *command_line) + +{ + long block_bitmap_offset; + char buffer [80]; + + block_bitmap_info.entry_num=0; + block_bitmap_info.group_num=group_info.group_num; + + block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap; + sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype block_bitmap");dispatch (buffer); +} +</code></tscreen> + +<sect>The inode table +<p> + +The inode handling enables the user to move in the inode table, edit the +various attributes of the inode, and follow to the next stage - A file or a +directory. + +<sect1>The inode variables +<p> + +<tscreen><code> +struct ext2_inode { + __u16 i_mode; /* File mode */ + __u16 i_uid; /* Owner Uid */ + __u32 i_size; /* Size in bytes */ + __u32 i_atime; /* Access time */ + __u32 i_ctime; /* Creation time */ + __u32 i_mtime; /* Modification time */ + __u32 i_dtime; /* Deletion Time */ + __u16 i_gid; /* Group Id */ + __u16 i_links_count; /* Links count */ + __u32 i_blocks; /* Blocks count */ + __u32 i_flags; /* File flags */ + union { + struct { + __u32 l_i_reserved1; + } linux1; + struct { + __u32 h_i_translator; + } hurd1; + struct { + __u32 m_i_reserved1; + } masix1; + } osd1; /* OS dependent 1 */ + __u32 i_block[EXT2_N_BLOCKS]; /* Pointers to blocks */ + __u32 i_version; /* File version (for NFS) */ + __u32 i_file_acl; /* File ACL */ + __u32 i_dir_acl; /* Directory ACL */ + __u32 i_faddr; /* Fragment address */ + union { + struct { + __u8 l_i_frag; /* Fragment number */ + __u8 l_i_fsize; /* Fragment size */ + __u16 i_pad1; + __u32 l_i_reserved2[2]; + } linux2; + struct { + __u8 h_i_frag; /* Fragment number */ + __u8 h_i_fsize; /* Fragment size */ + __u16 h_i_mode_high; + __u16 h_i_uid_high; + __u16 h_i_gid_high; + __u32 h_i_author; + } hurd2; + struct { + __u8 m_i_frag; /* Fragment number */ + __u8 m_i_fsize; /* Fragment size */ + __u16 m_pad1; + __u32 m_i_reserved2[2]; + } masix2; + } osd2; /* OS dependent 2 */ +}; +</code></tscreen> + +The above is the original source code definition. We can see that the inode +supports <tt>Operating systems specific structures</>. In addition to the +expansion of the arrays, I have <tt>"flattened</> the inode to support only +the <tt>Linux</> declaration. It seemed that this one occasion of multiple +variable aliases didn't justify the complication of generally supporting +aliases. In any case, the above system specific variables are not used +internally by EXT2ED, and the user is free to change the definition in +<tt>ext2.descriptors</> to accommodate for his needs. + +<sect1>The handling functions +<p> + +The user interface to <tt>movement</> is the usual <tt>next / prev / +entry</> interface. There is really nothing special in those functions - The +size of the inode is fixed, the total number of inodes is known from the +superblock information, and the current entry can be figured up from the +device offset and the inode table start offset, which is known from the +corresponding group descriptor. Those functions are a bit older then some +other implementations of <tt>next</> and <tt>prev</>, and they do not save +information in a special structure. Rather, they recompute it when +necessary. + +The <tt>show</> command is overridden here, and provides a lot of additional +information about the inode - Its type, interpretation of the permissions, +special ext2 attributes (Immutable file, for example), and a lot more. +Again, the <tt>general show</> is called first, and then the additional +information is written. + +<sect1>Accessing files and directories +<p> + +From the inode, a <tt>file</> or a <tt>directory</> can typically be reached. +In order to treat a file, for example, its inode needs to be constantly +accessed. To satisfy that need, when editing a file or a directory, the +inode is still saved in memory - <tt>type_data</> is not overwritten. +Rather, the following takes place: +<itemize> +<item> An internal global structure which is used by the types <tt>file</> + and <tt>dir</> handling functions is initialized by calling the + appropriate function. +<item> The type is changed accordingly. +</itemize> +The result is that a <tt>settype ext2_inode</> is the only action necessary +to return to the inode - We actually never left it. + +Follows the implementation of the inode's <tt>file</> command: + +<tscreen><code> +void type_ext2_inode___file (char *command_line) + +{ + char buffer [80]; + + if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not file\n"); + refresh_command_win (); return; + } + + if (!init_file_info ()) { + wprintw (command_win,"Error - Unable to show file\n"); + refresh_command_win ();return; + } + + sprintf (buffer,"settype file");dispatch (buffer); +} +</code></tscreen> + +As we can see - We just call <tt>init_file_info</> to get the necessary +information from the inode, and set the type to <tt>file</>. The next call +to <tt>show</>, will dispatch to the <tt>file's show</> implementation. + +<sect>Viewing a file +<p> + +There isn't an ext2 kernel structure which corresponds to a file - A file is +just a series of blocks which are determined by its inode. As explained in +the last section, the inode is never actually left - The type is changed to +<tt>file</> - A type which contains no variables, and a special structure is +initialized: + +<tscreen><code> +struct struct_file_info { + + struct ext2_inodes *inode_ptr; + + long inode_offset; + long global_block_num,global_block_offset; + long block_num,blocks_count; + long file_offset,file_length; + long level; + unsigned char buffer [EXT2_MAX_BLOCK_SIZE]; + long offset_in_block; + + int display; + /* The following is used if the file is a directory */ + + long dir_entry_num,dir_entries_count; + long dir_entry_offset; +}; +</code></tscreen> + +The <tt>inode_ptr</> will just point to the inode in <tt>type_data</>, which +is not overwritten while the user is editing the file, as the +<tt>setoffset</> command is not internally used. The <tt>buffer</> +will contain the current viewed block of the file. The other variables +contain information about the current place in the file. For example, +<tt>global_block_num</> just contains the current block number. + +The general idea is that the above data structure will provide the file +handling functions all the accurate information which is needed to accomplish +their task. + +The global structure of the above type, <tt>file_info</>, is initialized by +<tt>init_file_info</> in <tt>file_com.c</>, which is called by the +<tt>type_ext2_inode___file</> function when the user requests to watch the +file. <tt>It is updated as necessary to provide accurate information as long as +the file is edited.</> + +<sect1>Returning to the file's inode +<p> + +Concerning the method I used to handle files, the above task is trivial: +<tscreen><code> +void type_file___inode (char *command_line) + +{ + dispatch ("settype ext2_inode"); +} +</code></tscreen> + +<sect1>File movement +<p> + +EXT2ED keeps track of the current position in the file. Movement inside the +current block is done using <tt>next, prev and offset</> - They just change +<tt>file_info.offset_in_block</>. + +Movement between blocks is done using <tt>nextblock, prevblock and block</>. +To accomplish this, the direct blocks, indirect blocks, etc, need to be +traced. This is done by <tt>file_block_to_global_block</>, which accepts a +file's internal block number, and converts it to the actual filesystem block +number. + +<tscreen><code> +long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr) + +{ + long last_direct,last_indirect,last_dindirect; + long f_indirect,s_indirect; + + last_direct=EXT2_NDIR_BLOCKS-1; + last_indirect=last_direct+file_system_info.block_size/4; + last_dindirect=last_indirect+(file_system_info.block_size/4) \ + *(file_system_info.block_size/4); + + if (file_block <= last_direct) { + file_info_ptr->level=0; + return (file_info_ptr->inode_ptr->i_block [file_block]); + } + + if (file_block <= last_indirect) { + file_info_ptr->level=1; + file_block=file_block-last_direct-1; + return (return_indirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_IND_BLOCK],file_block)); + } + + if (file_block <= last_dindirect) { + file_info_ptr->level=2; + file_block=file_block-last_indirect-1; + return (return_dindirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_DIND_BLOCK],file_block)); + } + + file_info_ptr->level=3; + file_block=file_block-last_dindirect-1; + return (return_tindirect (file_info_ptr->inode_ptr-> \ + i_block [EXT2_TIND_BLOCK],file_block)); +} +</code></tscreen> +<tt>last_direct, last_indirect, etc</>, contain the last internal block number +which is accessed by this method - If the requested block is smaller then +<tt>last_direct</>, for example, it is a direct block. + +If the block is a direct block, its number is just taken from the inode. +A non-direct block is handled by <tt>return_indirect, return_dindirect and +return_tindirect</>, which correspond to indirect, double-indirect and +triple-indirect. Each of the above functions is constructed using the lower +level functions. For example, <tt>return_dindirect</> is constructed as +follows: + +<tscreen><code> +long return_dindirect (long table_block,long block_num) + +{ + long f_indirect; + + f_indirect=block_num/(file_system_info.block_size/4); + f_indirect=return_indirect (table_block,f_indirect); + return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4))); +} +</code></tscreen> + +<sect1>Object memory +<p> + +The <tt>remember</> command is overridden here and in the <tt>dir</> type - +We just remember the inode of the file. It is just simpler to implement, and +doesn't seem like a big limitation. + +<sect1>Changing data +<p> + +The <tt>set</> command is overridden, and provides the same functionality +like the usage of the <tt>general set</> command with no type declared. The +<tt>writedata</> is overridden so that we'll write the edited block +(file_info.buffer) and not <tt>type_data</> (Which contains the inode). + +<sect>Directories +<p> + +A directory is just a file which is formatted according to a special format. +As such, EXT2ED handles directories and files quite alike. Specifically, the +same variable of type <tt>struct_file_info</> which is used in the +<tt>file</>, is used here. + +The <tt>dir</> type uses all the variables in the above structure, as +opposed to the <tt>file</> type, which didn't use the last ones. + +<sect1>The search_dir_entries function +<p> + +The entire situation is similar to that which was described in the +<tt>file</> type, with one main change: + +The main function in <tt>dir_com.c</> is <tt>search_dir_entries</>. This +function will <tt>"run"</> on the entire entries in the directory, and will +call a client's function each time. The client's function is supplied as an +argument, and will check the current entry for a match, based on its own +criterion. It will then signal <tt>search_dir_entries</> whether to +<tt>ABORT</> the search, whether it <tt>FOUND</> the entry it was looking +for, or that the entry is still not found, and we should <tt>CONTINUE</> +searching. Follows the declaration: +<tscreen><code> +struct struct_file_info search_dir_entries \ + (int (*action) (struct struct_file_info *info),int *status) + +/* + This routine runs on all directory entries in the current directory. + For each entry, action is called. The return code of action is one of + the following: + + ABORT - Current dir entry is returned. + CONTINUE - Continue searching. + FOUND - Current dir entry is returned. + + If the last entry is reached, it is returned, along with an ABORT status. + + status is updated to the returned code of action. +*/ +</code></tscreen> + +With the above tool in hand, many operations are simple to perform - Here is +the way I counted the entries in the current directory: + +<tscreen><code> +long count_dir_entries (void) + +{ + int status; + + return (search_dir_entries (&ero;action_count,&ero;status).dir_entry_num); +} + +int action_count (struct struct_file_info *info) + +{ + return (CONTINUE); +} +</code></tscreen> +It will just <tt>CONTINUE</> until the last entry. The returned structure +(of type <tt>struct_file_info</>) will have its number in the +<tt>dir_entry_num</> field, and this is exactly the required number ! + +<sect1>The cd command +<p> + +The <tt>cd</> command accepts a relative path, and moves there ... +The implementation is of-course a bit more complicated: +<enum> +<item> The path is checked that it is not an absolute path (from <tt>/</>). + If it is, we let the <tt>general cd</> to do the job by calling + directly <tt>type_ext2___cd</>. +<item> The path is divided into the nearest path and the rest of the path. + For example, cd 1/2/3/4 is divided into <tt>1</> and into + <tt>2/3/4</>. +<item> It is the first part of the path that we need to search for in the + current directory. We search for it using <tt>search_dir_entries</>, + which accepts the <tt>action_name</> function as the user defined + function. +<item> <tt>search_dir_entries</> will scan the entire entries and will call + our <tt>action_name</> function for each entry. In + <tt>action_name</>, the required name will be checked against the + name of the current entry, and <tt>FOUND</> will be returned when a + match occurs. +<item> If the required entry is found, we dispatch a <tt>remember</> + command to insert the current <tt>inode</> into the object memory. + This is required to easily support <tt>symbolic links</> - If we + find later that the inode pointed by the entry is actually a + symbolic link, we'll need to return to this point, and the above + inode doesn't have (and can't have, because of <tt>hard links</>) the + information necessary to "move back". +<item> We then dispatch a <tt>followinode</> command to reach the inode + pointed by the required entry. This command will automatically + change the type to <tt>ext2_inode</> - We are now at an inode, and + all the inode commands are available. +<item> We check the inode's type to see if it is a directory. If it is, we + dispatch a <tt>dir</> command to "enter the directory", and + recursively call ourself (The type is <tt>dir</> again) by + dispatching a <tt>cd</> command, with the rest of the path as an + argument. +<item> If the inode's type is a symbolic link (only fast symbolic link were + meanwhile implemented. I guess this is typically the case.), we note + the path it is pointing at, the saved inode is recalled, we dispatch + <tt>dir</> to get back to the original directory, and we call + ourself again with the <tt>link path/rest of the path</> argument. +<item> In any other case, we just stop at the resulting inode. +</enum> + +<sect>The block and inode allocation bitmaps +<p> + +The block allocation bitmap is reached by the corresponding group descriptor. +The group descriptor handling functions will save the necessary information +into a structure of the <tt>struct_block_bitmap_info</> type: + +<tscreen><code> +struct struct_block_bitmap_info { + unsigned long entry_num; + unsigned long group_num; +}; +</code></tscreen> + +The <tt>show</> command is overridden, and will show the block as a series of +bits, each bit corresponding to a block. The main variable is the +<tt>entry_num</> variable, declared above, which is just the current block +number in this block group. The current entry is highlighted, and the +<tt>next, prev and entry</> commands just change the above variable. + +The <tt>allocate and deallocate</> change the specified bits. Nothing +special about them - They just contain code which converts between bit and +byte locations. + +The <tt>inode allocation bitmap</> is treated in much the same fashion, with +the same commands available. + +<sect>Filesystem size limitation +<p> + +While an ext2 filesystem has a size limit of <tt>4 TB</>, EXT2ED currently +<tt>can't</> handle filesystems which are <tt>bigger than 2 GB</>. + +This limitation results from my usage of <tt>32 bit long variables</> and +of the <tt>fseek</> filesystem call, which can't seek up to 4 TB. + +By looking in the <tt>ext2 library</> source code by <tt>Theodore Ts'o</>, +I discovered the <tt>llseek</> system call which can seek to a +<tt>64 bit unsigned long long</> offset. Correcting the situation is not +difficult in concept - I need to change long into unsigned long long where +appropriate and modify <tt>disk.c</> to use the llseek system call. + +However, fixing the above limitation involves making changes in many places +in the code and will obviously make the entire code less stable. For that +reason, I chose to release EXT2ED as it is now and to postpone the above fix +to the next release. + +<sect>Conclusion +<p> + +Had I known in advance the structure of the ext2 filesystem, I feel that +the resulting design would have been quite different from the presented +design above. + +EXT2ED has now two levels of abstraction - A <tt>general</> filesystem, and an +<tt>ext2</> filesystem, and the surface is more or less prepared for additions +of other filesystems. Had I approached the design in the "engineering" way, +I guess that the first level above would not have existed. + +<sect>Copyright +<p> + +EXT2ED is Copyright (C) 1995 Gadi Oxman. + +EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and +welcome to copy, view and modify the sources. My only wish is that my +copyright presented above will be left and that a list of the bug fixes, +added features, etc, will be provided. + +The entire EXT2ED project is based, of-course, on the kernel sources. The +<tt>ext2.descriptors</> distributed with EXT2ED is a slightly modified +version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows +the original copyright: + +<tscreen><verb> +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +</verb></tscreen> + +<sect>Acknowledgments +<p> + +EXT2ED was constructed as a student project in the software +laboratory of the faculty of electrical-engineering in the +<tt>Technion - Israel's institute of technology</>. + +At first, I would like to thank <tt>Avner Lottem</> and <tt>Doctor Ilana +David</> for their interest and assistance in this project. + +I would also like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: +<itemize> +<item> <tt>Remy Card</> + + Who designed, implemented and maintains the ext2 filesystem kernel + code, and some of the ext2 utilities. <tt>Remy Card</> is also the + author of several helpful slides concerning the ext2 filesystem. + Specifically, he is the author of <tt>File Management in the Linux + Kernel</> and of <tt>The Second Extended File System - Current + State, Future Development</>. + +<item> <tt>Wayne Davison</> + + Who designed the ext2 filesystem. +<item> <tt>Stephen Tweedie</> + + Who helped designing the ext2 filesystem kernel code and wrote the + slides <tt>Optimizations in File Systems</>. +<item> <tt>Theodore Ts'o</> + + Who is the author of several ext2 utilities and of the ext2 library + <tt>libext2fs</> (which I didn't use, simply because I didn't know + it exists when I started to work on my project). +</itemize> + +Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the +<tt>Linux community</> for providing all of us with such a great operating +system. + +Please contact me in a case of bug report, suggestions, or just about +anything concerning EXT2ED. + +Enjoy, + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + +Haifa, August 95 +</article> \ No newline at end of file diff --git a/ext2ed/doc/ext2ed.8 b/ext2ed/doc/ext2ed.8 new file mode 100644 index 00000000..e153ff8b --- /dev/null +++ b/ext2ed/doc/ext2ed.8 @@ -0,0 +1,72 @@ +.\" -*- nroff -*- +.TH EXT2ED 8 "August 1995" "Version 0.1" +.SH NAME +ext2ed \- ext2 file system editor +.SH SYNOPSIS +.B ext2ed +.SH DESCRIPTION +.B ext2ed +in an +.B editor +for the +.B second extended filesystem. +Its aim is to show you the various internal filesystem structures in an +intuitive form so that you would be able to easily understand and modify +them. +.SH DOCUMENTATION +The documentation is not available in man page format. Instead, I have +written three articles which are related to ext2ed: + +The first article is +.B The user's guide. +This article explains how to use ext2ed. + +The second article is +.B The Ext2fs overview. +This article gives an overview of internal structure of the ext2 filesystem. +You need to understand the internal layout in order to effectively edit +your filesystem. + +The third article is +.B EXT2ED - Design and implementation. +This article explains how I constructed ext2ed. You may want to have a look +in it if you plan to view or modify the source code. + +.SH WARNING + +.B +Do not use ext2ed on a mounted filesystem. + +.SH FILES +.TP +.I /usr/bin/ext2ed +The program itself. +.TP +.I /var/lib/ext2ed/ext2ed.conf +ext2ed's configuration file. +.TP +.I /var/lib/ext2ed/ext2.descriptors +Definition of the various objects for the ext2 filesystem. +.TP +.I /var/lib/ext2ed/ext2ed.log +Log file of actual changes made to the filesystem. +.TP +.I /usr/man/man8/ext2ed.8 +The manual page. +.TP +.I /usr/doc/ext2ed/user-guide-0.1.ps +The user's guide. +.TP +.I /usr/doc/ext2ed/Ext2fs-overview-0.1.ps +Technical overview of the ext2 filesystem. +.TP +.I /usr/doc/ext2ed/ext2ed-design-0.1.ps +EXT2ED design notes. + +.SH BUGS +Filesystems bigger than 2 GB aren't yet supported. +.SH AUTHOR +Gadi Oxman <tgud@tochnapc2.technion.ac.il> +.SH SEE ALSO +.BR e2fsck (8), +.BR debugfs (8) diff --git a/ext2ed/doc/user-guide-0.1.sgml b/ext2ed/doc/user-guide-0.1.sgml new file mode 100644 index 00000000..c494a7e7 --- /dev/null +++ b/ext2ed/doc/user-guide-0.1.sgml @@ -0,0 +1,1189 @@ +<!doctype linuxdoc system> + +<!-- EXT2ED user's guide --> +<!-- First written: July 22 1995 --> +<!-- Last updated: August 3 1995 --> +<!-- This document is written Using the Linux documentation project Linuxdoc-SGML DTD --> + +<article> + +<title>EXT2ED - The Extended-2 filesystem editor - User's guide +<author>Gadi Oxman, tgud@tochnapc2.technion.ac.il +<date>v0.1, August 3 1995 +<abstract> +This is only the initial version of this document. It may be unclear at +some places. Please send me feedback with anything regarding to it. +</abstract> +<toc> + +<!-- Begin of document --> + +<sect>About EXT2ED documentation +<p> + +The EXT2ED documentation consists of three parts: +<itemize> +<item> The ext2 filesystem overview. +<item> The EXT2ED user's guide. +<item> The EXT2ED design and implementation. +</itemize> + +If you intend to used EXT2ED, I strongly suggest that you would be familiar +with the material presented in the <tt>ext2 filesystem overview</> as well. + +If you also intend to browse and modify the source code, I suggest that you +will also read the article <tt>The EXT2ED design and implementation</>, as it +provides a general overview of the structure of my source code. + +<sect>Introduction + +<p> +EXT2ED is a "disk editor" for the ext2 filesystem. Its purpose is to show +you the internal structures of the ext2 filesystem in an rather intuitive +and logical way, so that it will be easier to "travel" between the various +internal filesystem structures. + +<sect>Basic concepts in EXT2ED + +<p> +Two basic concepts in EXT2ED are <tt>commands</> and <tt>types</>. + +EXT2ED is object-oriented in the sense that it defines objects in the +filesystem, like a <tt>super-block</> or a <tt>directory</>. An object is +something which "knows" how to handle some aspect of the filesystem. + +Your interaction with EXT2ED is done through <tt>commands</> which EXT2ED +accepts. There are three levels of commands: +<itemize> +<item> General Commands +<item> Extended-2 Filesystem general commands +<item> Type specific commands +</itemize> +The General commands are always available. + +The ext2 general commands are available only when editing an ext2 filesystem. + +The Type specific commands are available when editing a specific object in the +filesystem. Each object typically comes with its own set of internal +variables, and its own set of commands, which are fine tuned handle the +corresponding structure in the filesystem. +<sect>Running EXT2ED +<p> +Running EXT2ED is as simple as typing <tt>ext2ed</> from the shell prompt. +There are no command line switches. + +When first run, EXT2ED parses its configuration file, <tt>ext2ed.conf</>. +This file must exist. + +When the configuration file processing is done, EXT2ED screen should appear +on the screen, with the command prompt <tt>ext2ed></> displayed. + +<sect>EXT2ED user interface + +<p> +EXT2ED uses the <em>ncurses</> library for screen management. Your screen +will be divided into four parts, from top to bottom: +<itemize> +<item> Title window +<item> Status window +<item> Main editing window +<item> Command window +</itemize> +The title window just displays the current version of EXT2ED. + +The status window will display various information regarding the state of +the editing at this point. + +The main editing window is the place at which the actual data will be shown. +Almost every command will cause some display at this window. This window, as +opposed to the three others, is of variable length - You always look at one +page of it. The current page and the total numbers of pages at this moment +is displayed at the status window. Moving between pages is done by the use +of the <tt>pgdn</> and <tt>pgup</> commands. + +The command window is at the bottom of the screen. It always displays a +command prompt <tt>ext2ed></> and allows you to type a command. Feedback +about the commands entered is displayed to this window also. + +EXT2ED uses the <em>readline</> library while processing a command line. All +the usual editing keys are available. Each entered command is placed into a +history of commands, and can be recalled later. Command Completion is also +supported - Just start to type a command, and press the completion key. + +Pressing <tt>enter</> at the command window, without entering a command, +recalls the last command. This is useful when moving between close entries, +in the <tt>next</> command, for example. + +<sect>Getting started + +<p> + +<sect1>A few precautions + +<p> + +EXT2ED is a tool for filesystem <tt>editing</>. As such, it can be +<tt>dangerous</>. The summary to the subsections below is that +<tt>You must know what you are doing</>. + +<sect2><label id="mounted_ref">A mounted filesystem + +<p> + +EXT2ED is not designed to work on a mounted filesystem - It is complicated +enough as it is; I didn't even try to think of handling the various race +conditions. As such, please respect the following advice: + +<tt>Do not use EXT2ED on a mounted filesystem !</> + +EXT2ED will not allow write access to a mounted filesystem. Although it is +fairly easy to change EXT2ED so that it will be allowed, I hereby request +again- EXT2ED is not designed for that action, and will most likely corrupt +data if used that way. Please don't do that. + +Concerning read access, I chose to leave the decision for the user through +the configuration file option <tt>AllowMountedRead</>. Although read access +on a mounted partition will not do any damage to the filesystem, the data +displayed to you will not be reliable, and showing you incorrect information +may be as bad as corrupting the filesystem. However, you may still wish to +do that. + +<sect2>Write access + +<p> + +Considering the obvious sensitivity of the subject, I took the following +actions: + +<enum> +<item> EXT2ED will always start with a read-only access. Write access mode + needs to be specifically entered by the <tt>enablewrite</> command. + Until this is done, no write will be allowed. Write access can be + disabled at any time with <tt>disablewrite</>. When + <tt>enablewrite</> is issued, the device is reopened in read-write + mode. Needless to say, the device permissions should allow that. +<item> As a second level of protection, you can disallow write access in + the configuration file by using the <tt>AllowChanges off</> + configuration option. In this case, the <tt>enablewrite</> command + will be refused. +<item> When write access is enabled, the data will never change + immediately. Rather, a specific <tt>writedata</> command is needed + to update the object in the disk with the changed object in memory. +<item> In addition, A logging option is provided through the configuration + file options <tt>LogChanges</> and <tt>LogFile</>. With logging + enabled, each change to the disk will be logged at a very primitive + level - A hex dump of the original data and of the new written data. + The log file will be a text file which is easily readable, and you + can make use of it to undo any changes which you made (EXT2ED doesn't + make use of the log file for that purpose, it just logs the changes). +</enum> +Please remember that this is only the initial release of EXT2ED, and it is +not very much tested - It is reasonable to assume that <tt>there are +bugs</>. +However, the logging option above can offer protection even from this +unfortunate case. Therefor, I highly recommend that at least when first +working with EXT2ED, the logging option will be enabled, despite the disk +space which it consumes. + +<sect1><label id="help_ref">The help command + +<p> + +When loaded, EXT2ED will show a short help screen. This help screen can +always be retrieved by the command <tt>help</>. The help screen displays a +list of all the commands which are available at this point. At startup, only +the <tt>General commands</> are available. +This will change with time, since each object has its own commands. Thus, +commands which are available now may not be available later. +Using <tt>help</> <em>command</> will display additional information about +the specific command <em>command</>. + +<sect1><label id="setdevice_ref">The setdevice command + +<p> + +The first command that is usually entered to EXT2ED is the <tt>setdevice</> +command. This command simply tells EXT2ED on which device the filesystem is +present. For example, suppose my ext2 filesystem is on the first partition +of my ide disk. The command will be: +<tscreen><verb> +setdevice /dev/hda1 +</verb></tscreen> +The following actions will take place in the following order: +<enum> +<item> EXT2ED will check if the partition is mounted. + If the partition is mounted (<tt>highly not recommended</>), + the accept/reject behavior will be decided by the configuration + file. Cross reference section <ref id="mounted_ref">. +<item> The specified device will be opened in read-only mode. The + permissions of the device should be set in a way that allows + you to open the device for read access. +<item> Autodetection of an ext2 filesystem will be made by searching for + the ext2 magic number in the main superblock. +<item> In the case of a successful recognition of an ext2 filesystem, the + ext2 filesystem specific commands and the ext2 specific object + definitions will be registered. The object definitions will be read + at run time from a file specified by the configuration file. + + In case of a corrupted ext2 filesystem, it is quite possible that + the main superblock is damaged and autodetection will fail. In that + case, use the configuration option <tt>ForceExt2 on</>. This is not + the default case since EXT2ED can be used at a lower level to edit a + non-ext2 filesystem. +<item> In a case of a successful autodetection, essential information about + the filesystem such as the block size will be read from the + superblock, unless the used overrides this behavior with an + configuration option (not recommended). In that case, the parameters + will be read from the configuration file. + + In a case of an autodetection failure, the essential parameters + will be read from the configuration file. +</enum> +Assuming that you are editing an ext2 filesystem and that everything goes +well, you will notice that additional commands are now available in the help +screen, under the section <tt>ext2 filesystem general commands</>. In +addition, EXT2ED now recognizes a few objects which are essential to the +editing of an ext2 filesystem. + +<sect>Two levels of usage + +<p> + +<sect1>Low level usage + +<p> +This section explains what EXT2ED provides even when not editing an ext2 +filesystem. + +Even at this level, EXT2ED is more than just a hex editor. It still allows +definition of objects and variables in run time through a user file, +although of-course the objects will not have special fine tuned functions +connected to them. EXT2ED will allow you to move in the filesystem using +<tt>setoffset</>, and to apply an object definition on a specific place +using <tt>settype</> <em>type</>. From this point and on, the object will +be shown <tt>in its native form</> - You will see a list of the +variables rather than just a hex dump, and you will be able to change each +variable in the intuitive form <tt>set variable=value</>. + +To define objects, use the configuration option <tt>AlternateDescriptors</>. + +There are now two forms of editing: +<itemize> +<item> Editing without a type. In this case, the disk block will be shown +as a text+hex dump, and you will be able to move along and change it. +<item> Editing with a type. In this case, the object's variables will be +shown, and you will be able to change each variable in its native form. +</itemize> + +<sect1>High level usage + +<p> +EXT2ED was designed for the editing of the ext2 filesystem. As such, it +"understands" the filesystem structure to some extent. Each object now has +special fine tuned 'C' functions connected to it, which knows how to display +it in an intuitive form, and how the object fits in the general design of +the ext2 filesystem. It is of-course much easier to use this type of +editing. For example: +<tscreen> +Issue <em>group 2</> to look at the main copy of the third group block +descriptor. With <em>gocopy 1</> you can move to its first backup copy, +and with <em>inode</> you can start editing the inode table of the above +group block. From here, if the inode corresponds to a file, you can +use <em>file</> to edit the file in a "continuous" way, using +<em>nextblock</> to pass to its next block, letting EXT2ED following by +itself the direct blocks, indirect blocks, ..., while still preserving the +actual view of the exact block usage of the file. +</tscreen> +The point is that the "tour" of the filesystem will now be synchronic rather +than asynchronic - Each object has the "links" to pass between connected +logical structures, and special fine-tuned functions to deal with it. + +<sect>General commands + +<p> +I will now start with a systematic explanation of the general commands. +Please feel free to experiment, but take care when using the +<tt>enablewrite</> command. + +Whenever a command syntax is specified, arguments which are optional are +enclosed with square brackets. + +Please note that in EXT2ED, each command can be overridden by a specific +object to provide special fine-tuned functionality. In general, I was +attempting to preserve the similarity between those functions, which are +accessible by the same name. + +<sect1><label id="disablewrite_ref">disablewrite +<p> +<tscreen><verb> +Syntax: disablewrite +</verb></tscreen> +<tt>disablewrite</> is used to reopen the device with read-only access. When +first running EXT2ED, the device is opened in read-only mode, and an +explicit <tt>enablewrite</> is required for write access. When finishing +with changing, a <tt>disablewrite</> is recommended for safety. Cross +reference section <ref id="disablewrite_ref">. + +<sect1><label id="enablewrite_ref">enablewrite +<p> +<tscreen><verb> +Syntax: enablewrite +</verb></tscreen> +<tt>enablewrite</> is used to reopen the device with read-write access. +When first running EXT2ED, the device is opened in read-only mode, and an +explicit <tt>enablewrite</> is required for write access. +<tt>enablewrite</> will fail if write access is disabled from the +configuration file by the <tt>AllowChanges off</> configuration option. +Even after <tt>enablewrite</>, an explicit <tt>writedata</> +is required to actually write the new data to the disk. +When finishing with changing, a <tt>disablewrite</> is recommended for safety. +Cross reference section <ref id="enablewrite_ref">. + +<sect1>help +<p> +<tscreen><verb> +Syntax: help [command] +</verb></tscreen> +The <tt>help</> command is described at section <ref id="help_ref">. + +<sect1><label id="next_ref">next +<p> +<tscreen><verb> +Syntax: next [number] +</verb></tscreen> +This section describes the <em>general command</> <tt>next</>. <tt>next</> +is overridden by several types in EXT2ED, to provide fine-tuned +functionality. + +The <tt>next general command</> behavior is depended on whether you are editing a +specific object, or none. + +<itemize> +<item> In the case where Type is <tt>none</> (The current type is showed + on the status window by the <tt>show</> command), <tt>next</> + passes to the next <em>number</> bytes in the current edited block. + If <em>number</> is not specified, <em>number=1</> is assumed. +<item> In the case where Type is defined, the <tt>next</> commands assumes + that you are editing an array of objects of that type, and the + <tt>next</> command will just pass to the next entry in the array. + If <em>number</> is defined, it will pass <em>number</> entries + ahead. +</itemize> + +<sect1><label id="pgdn_ref">pgdn +<p> +<tscreen><verb> +Syntax: pgdn +</verb></tscreen> +Usually the edited data doesn't fit into the visible main window. In this +case, the status window will indicate that there is more to see "below" by +the message <tt>Page x of y</>. This means that there are <em>y</> pages +total, and you are currently viewing the <em>x</> page. With the <tt>pgdn</> +command, you can pass to the next available page. + +<sect1>pgup +<p> +<tscreen><verb> +Syntax: pgup +</verb></tscreen> + +<tt>pgup</> is the opposite of <tt>pgdn</> - It will pass to the previous +page. Cross reference section <ref id="pgdn_ref">. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [number] +</verb></tscreen> + +<tt>prev</> is the opposite of <tt>next</>. Cross reference section +<ref id="next_ref">. + +<sect1><label id="recall_ref">recall +<p> +<tscreen><verb> +Syntax: recall object +</verb></tscreen> +<tt>recall</> is the opposite of <tt>remember</>. It will place you at the +place you where when saving the object position and type information. Cross +reference section <ref id="remember_ref">. + +<sect1>redraw +<p> +<tscreen><verb> +Syntax: redraw +</verb></tscreen> +Sometimes the screen display gets corrupted. I still have problems with +this. The <tt>redraw</> command simply redraws the entire display screen. + +<sect1><label id="remember_ref">remember +<p> +<tscreen><verb> +Syntax: remember object +</verb></tscreen> +EXT2ED provides you <tt>memory</> of objects; While editing, you may reach an +object which you will like to return to later. The <tt>remember</> command +will store in memory the current place and type of the object. You can +return to the object by using the <tt>recall</> command. Cross reference +section <ref id="recall_ref">. + +<tt>Note:</> +<itemize> +<item> When remembering a <tt>file</> or a <tt>directory</>, the + corresponding inode will be saved in memory. The basic reason is that + the inode is essential for finding the blocks of the file or the + directory. +</itemize> + +<sect1>set +<p> +<tscreen><verb> +Syntax: set [text || hex] arg1 [arg2 arg3 ...] + +or + +Syntax: set variable=value +</verb></tscreen> +The <tt>set</> command is used to modify the current data. +The <tt>set general command</> behavior is depended on whether you are editing a +specific object, or none. + +<itemize> +<item> In the case where Type is <tt>none</>, the first syntax should be + used. The set command affects the data starting at the current + highlighted position in the edited block. + <itemize> + <item> When using the <tt>set hex</> command, a list of + hexadecimal bytes should follow. + <item> When using the <tt>set text</> command, it should be followed + by a text string. + </itemize> + Examples: + <tscreen><verb> + set hex 09 0a 0b 0c 0d 0e 0f + set text Linux is just great ! + </verb></tscreen> +<item> In the case where Type is defined, the second syntax should be used. + The set commands just sets the variable <em>variable</> with the + value <em>value</>. +</itemize> +In any case, the data is only changed in memory. For an actual update to the +disk, use the <tt>writedata</> command. + +<sect1>setdevice +<p> +<tscreen><verb> +Syntax: setdevice device +</verb></tscreen> +The <tt>setdevice</> command is described at section <ref id="setdevice_ref">. + +<sect1>setoffset +<p> +<tscreen><verb> +Syntax: setoffset [block || type] [+|-]offset +</verb></tscreen> +The <tt>setoffset</> command is used to move asynchronically inside the file +system. It is considered a low level command, and usually should not be used +when editing an ext2 filesystem, simply because movement is better +utilized through the specific ext2 commands. + +The <tt>offset</> is in bytes, and meanwhile should be positive and smaller +than 2GB. + +Use of the <tt>block</> modifier changes the counting unit to block. + +Use of the <tt>+ or -</> modifiers signals that the offset is relative to +the current position. + +use of the <tt>type</> modifier is allowed only with relative offset. This +modifier will multiply the offset by the size of the current type. + +<sect1>settype +<p> +<tscreen><verb> +Syntax: settype type || [none | hex] +</verb></tscreen> +The <tt>settype</> command is used to move apply the object definitions of +the type <em>type</> on the current position. It is considered a low level +command and usually should not be used when editing an ext2 filesystem since +EXT2ED provides better tools. It is of-course very useful when editing a +non-ext2 filesystem and using user-defined objects. + +When <em>type</> is <em>hex</> or <em>none</>, the data will be displayed as +a hex and text dump. + +<sect1>show +<p> +<tscreen><verb> +Syntax: show +</verb></tscreen> +The <tt>show</> command will show the data of the current object at the +current position on the main display window. It will also update the status +window with type specific information. It may be necessary to use +<tt>pgdn</> and <tt>pgup</> to view the entire data. + +<sect1>writedata +<p> +<tscreen><verb> +Syntax: writedata +</verb></tscreen> +The <tt>writedata</> command will update the disk with the object data that +is currently in memory. This is the point at which actual change is made to +the filesystem. Without this command, the edited data will not have any +effect. Write access should be allowed for a successful update. + +<sect>Editing an ext2 filesystem +<p> + +In order to edit an ext2 filesystem, you should, of course, know the structure +of the ext2 filesystem. If you feel that you lack some knowledge in this +area, I suggest that you do some of the following: +<itemize> +<item> Read the supplied ext2 technical information. I tried to summarize + the basic information which is needed to get you started. +<item> Get the slides that Remy Card (The author of the ext2 filesystem) + prepared concerning the ext2 filesystem. +<item> Read the kernel sources. +</itemize> +At this point, you should be familiar with the following terms: +<tt>block, inode, superblock, block groups, block allocation bitmap, inode +allocation bitmap, group descriptors, file, directory.</>Most of the above +are objects in EXT2ED. + +When editing an ext2 filesystem it is recommended that you use the ext2 +specific commands, rather then the general commands <tt>setoffset</> and +<tt>settype</>, mainly because: +<enum> +<item> In most cases it will be unreliable, and will display incorrect + information. + + Sometimes in order to edit an object, EXT2ED needs the information + of some other related objects. For example, when editing a + directory, EXT2ED needs access to the inode of the edited directory. + Simply setting the type to a directory <tt>will be unreliable</>, + since the object assumes that you passed through its inode to reach + it, and expects this information, which isn't initialized if you + directly set the type to a directory. +<item> EXT2ED offers far better tools for handling the ext2 filesystem + using the ext2 specific commands. +</enum> + +<sect>ext2 general commands +<p> + +The <tt>ext2 general commands</> are available only when you are editing an +ext2 filesystem. They are <tt>general</> in the sense that they are not +specific to some object, and can be invoked anytime. + +<sect1><label id="general_superblock">super +<p> +<tscreen><verb> +Syntax: super +</verb></tscreen> +The <tt>super</> command will "bring you" to the main superblock copy. It +will automatically set the object type to <tt>ext2_super_block</>. Then you +will be able to view and edit the superblock. When you are in the +superblock, other commands will be available. + +<sect1>group +<p> +<tscreen><verb> +Syntax: group [number] +</verb></tscreen> +The <tt>group</> command will "bring you" to the main copy of the +<em>number</> group descriptor. It will automatically set the object type to +<tt>ext2_group_desc</>. Then you will be able to view and edit the group +descriptor entry. When you are there, other commands will be available. + +<sect1>cd +<p> +<tscreen><verb> +Syntax: cd path +</verb></tscreen> +The <tt>cd</> command will let you travel in the filesystem in the nice way +that the mounted filesystem would have let you. + +The <tt>cd</> command is a complicated command. Although it may sound +simple at first, an implementation of a typical cd requires passing through +the group descriptors, inodes, directory entries, etc. For example: + +The innocent cd /usr command can be done by using more primitive +EXT2ED commands in the following way (It is implemented exactly this way): +<enum> +<item> Using <tt>group 0</> to go to the first group descriptor. +<item> Using <tt>inode</> to get to the Bad blocks inode. +<item> Using <tt>next</> to pass to the root directory inode. +<item> Using <tt>dir</> to see the directory. +<item> Using <tt>next</> until we find the directory usr. +<item> Using <tt>followinode</> to pass to the inode corresponding to usr. +<item> Using <tt>dir</> to see the directory of /usr. +</enum> +And those commands aren't that primitive; For example, the tracing of the +blocks which belong to the root directory is done automatically by the dir +command behind the scenes, and the followinode command will automatically +"run" to the correct group descriptor in order to find the required inode. + +The path to the <tt>general cd</> command needs to be a full pathname - +Starting from <tt>/</>. The <tt>cd</> command stops at the last reachable +point, which can be a directory entry, in which case the type will be set to +<tt>dir</>, or an inode, in which case the type will be set to +<tt>ext2_inode</>. Symbolic links (Only fast symbolic links, meanwhile) are +automatically followed (if they are not across filesystems, of-course). If +the type is set to <tt>dir</>, you can use a path relative to the +"current directory". + +<sect>The superblock +<p> +The superblock can always be reached by the ext2 general command +<tt>super</>. Cross reference section <ref id="general_superblock">. + +The status window will show you which copy of the superblock copies you are +currently editing. + +The main data window will show you the values of the various superblock +variables, along with some interpretation of the values. + +Data can be changed with the <tt>set</> and <tt>writedata</> commands. +<tscreen><verb> +For example, set s_r_blocks_count=1400 will reserve 1400 blocks for root. +</verb></tscreen> + +<sect1>gocopy +<p> +<tscreen><verb> +Syntax: gocopy number +</verb></tscreen> +The <tt>gocopy</> command will "bring you" to the backup copy <em>number</> +of the superblock copies. <tt>gocopy 0</>, for example, will bring you to +the main copy. + +<sect1>setactivecopy +<p> +<tscreen><verb> +Syntax: setactivecopy +</verb></tscreen> +The <tt>setactivecopy</> command will copy the contents of the current +superblock copy onto the contents of the main copy. It will also switch to +editing of the main copy. No actual data is written to disk, of-course, +until you issue the <tt>writedata</> command. + +<sect>The group descriptors +<p> +The group descriptors can be edited by the <tt>group</> command. + +The status window will indicate the current group descriptor, the total +number of group descriptors (and hence of group blocks), and the backup copy +number. + +The main data window will just show you the values of the various variables. + +Basically, you can use the <tt>next</> and <tt>prev</> commands, along with the +<tt>set</> command, to modify the group descriptors. + +The group descriptors object is a junction, from which you can reach: +<itemize> +<item> The inode table of the corresponding block group (the <tt>inode</> + command) +<item> The block allocation bitmap (the <tt>blockbitmap</> command) +<item> The inode allocation bitmap (the <tt>inodebitmap</> command) +</itemize> + +<sect1>blockbitmap +<p> +<tscreen><verb> +Syntax: blockbitmap +</verb></tscreen> +The <tt>blockbitmap</> command will let you edit the block bitmap allocation +block of the current group block. + +<sect1>entry +<p> +<tscreen><verb> +Syntax: entry number +</verb></tscreen> +The <tt>entry</> command will move you to the <em>number</> group descriptor in the +group descriptors table. + +<sect1>inode +<p> +<tscreen><verb> +Syntax: inode +</verb></tscreen> +The <tt>inode</> command will pass you to the first inode in the current +group block. + +<sect1>inodebitmap +<p> +<tscreen><verb> +Syntax: inodebitmap +</verb></tscreen> +The <tt>inodebitmap</> command will let you edit the inode bitmap allocation +block of the current group block. + +<sect1>next +<p> +<tscreen><verb> +Syntax: next [number] +</verb></tscreen> +The <tt>next</> command will pass to the next <em>number</> group +descriptor. If <em>number</> is omitted, <em>number=1</> is assumed. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [number] +</verb></tscreen> +The <tt>prev</> command will pass to the previous <em>number</> group +descriptor. If <em>number</> is omitted, <em>number=1</> is assumed. + +<sect1>setactivecopy +<p> +<tscreen><verb> +Syntax: setactivecopy +</verb></tscreen> +The <tt>setactivecopy</> command copies the contents of the current group +descriptor, to its main copy. The updated main copy will then be shown. No +actual change is made to the disk until you issue the <tt>writedata</> +command. + +<sect>The inode +<p> +An inode can be reached by the following two ways: +<itemize> +<item> Using <tt>inode</> from the corresponding group descriptor. +<item> Using <tt>followinode</> from a directory entry. +<item> Using the <tt>cd</> command with the pathname to the file. + + For example, <tt>cd /usr/src/ext2ed/ext2ed.h</> +</itemize> + +The status window will indicate: +<itemize> +<item> The current global inode number. +<item> The total total number of inodes. +<item> On which block group the inode is allocated. +<item> The total number of inodes in this group block. +<item> The index of the current inode in the current group block. +<item> The type of the inode (file, directory, special, etc). +</itemize> + +The main data window, in addition to the list of variables, will contain +some interpretations on the right side. + +If the inode corresponds to a file, you can use the <tt>file</> command to +edit the file. + +If the inode is an inode of a directory, you can use the <tt>dir</> command +to edit the directory. + +<sect1>dir +<p> +<tscreen><verb> +Syntax: dir +</verb></tscreen> +If the inode mode corresponds to a directory (shown on the status window), +you can enter directory mode editing by using <tt>dir</>. + +<sect1>entry +<p> +<tscreen><verb> +Syntax: entry number +</verb></tscreen> +The <tt>entry</> command will move you to the <em>number</> inode in the +current inode table. + +<sect1>file +<p> +<tscreen><verb> +Syntax: file +</verb></tscreen> +If the inode mode corresponds to a file (shown on the status window), +you can enter file mode editing by using <tt>file</>. + +<sect1>group +<p> +<tscreen><verb> +Syntax: group +</verb></tscreen> +The <tt>group</> command is used to go to the group descriptor of the +current group block. + +<sect1>next +<p> +<tscreen><verb> +Syntax: next [number] +</verb></tscreen> +The <tt>next</> command will pass to the next <em>number</> inode. +If <em>number</> is omitted, <em>number=1</> is assumed. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [number] +</verb></tscreen> +The <tt>prev</> command will pass to the previous <em>number</> inode. +If <em>number</> is omitted, <em>number=1</> is assumed. + +<sect>The file +<p> +When editing a file, EXT2ED offers you a both a continuous and a true +fragmented view of the file - The file is still shown block by block with +the true block number at each stage and EXT2ED offers you commands which +allow you to move between the <tt>file blocks</>, while finding the +allocated blocks by using the inode information behind the scenes. + +Aside from this, the editing is just a <tt>hex editing</> - You move the +cursor in the current block of the file by using <tt>next</> and +<tt>prev</>, move between blocks by <tt>nextblock</> and <tt>prevblock</>, +and make changes by the <tt>set</> command. Note that the set command is +overridden here - There are no variables. The <tt>writedata</> command will +update the current block to the disk. + +Reaching a file can be done by using the <tt>file</> command from its inode. +The <tt>inode</> can be reached by any other means, for example, by the +<tt>cd</> command, if you know the file name. + +The status window will indicate: +<itemize> +<item> The global block number. +<item> The internal file block number. +<item> The file offset. +<item> The file size. +<item> The file inode number. +<item> The indirection level - Whether it is a direct block (0), indirect + (1), etc. +</itemize> + +The main data window will display the file either in hex mode or in text +mode, select-able by the <tt>display</> command. + +In hex mode, EXT2ED will display offsets in the current block, along with a +text and hex dump of the current block. + +In either case the <tt>current place</> will be highlighted. In the hex mode +it will be always highlighted, while in the text mode it will be highlighted +if the character is display-able. + +<sect1>block +<p> +<tscreen><verb> +Syntax: block block_num +</verb></tscreen> +The <tt>block</> command is used to move inside the file. The +<em>block_num</> argument is the requested internal file block number. A +value of 0 will reach the beginning of the file. + +<sect1>display +<p> +<tscreen><verb> +Syntax: display [text || hex] +</verb></tscreen> +The <tt>display</> command changes the display mode of the file. <tt>display +hex</> will switch to <tt>hex mode</>, while <tt>display text</> will switch +to text mode. The default mode when no <tt>display</> command is issued is +<tt>hex mode</>. + +<sect1>inode +<p> +<tscreen><verb> +Syntax: inode +</verb></tscreen> +The <tt>inode</> command will return to the inode of the current file. + +<sect1>next +<p> +<tscreen><verb> +Syntax: next [num] +</verb></tscreen> +The <tt>next</> command will pass to the next byte in the file. If +<em>num</> is supplied, it will pass to the next <em>num</> bytes. + +<sect1>nextblock +<p> +<tscreen><verb> +Syntax: nextblock [num] +</verb></tscreen> +The <tt>nextblock</> command will pass to the next block in the file. If +<em>num</> is supplied, it will pass to the next <em>num</> blocks. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [num] +</verb></tscreen> +The <tt>prev</> command will pass to the previous byte in the file. If +<em>num</> is supplied, it will pass to the previous <em>num</> bytes. + +<sect1>prevblock +<p> +<tscreen><verb> +Syntax: prevblock [num] +</verb></tscreen> +The <tt>nextblock</> command will pass to the previous block in the file. If +<em>num</> is supplied, it will pass to the previous <em>num</> blocks. + +<sect1>offset +<p> +<tscreen><verb> +Syntax: offset file_offset +</verb></tscreen> +The <tt>offset</> command will move to the specified offset in the file. + +<sect1>set +<p> +<tscreen><verb> +Syntax: set [text || hex] arg1 [arg2 arg3 ...] +</verb></tscreen> +The <tt>file set</> command is working like the <tt>general set command</>, +with <tt>type=none</>. There are no variables. + +<sect1>writedata +<p> +<tscreen><verb> +Syntax: writedata +</verb></tscreen> +The <tt>writedata</> command will update the current file block in the disk. + +<sect>The directory +<p> +When editing a file, EXT2ED analyzes for you both the allocation blocks of +the directory entries, and the directory entries. + +Each directory entry is displayed on one row. You can move the highlighted +entry with the usual <tt>next</> and <tt>prev</> commands, and "dive in" +with the <tt>followinode</> command. + +The status window will indicate: +<itemize> +<item> The directory entry number. +<item> The total number of directory entries in this directory. +<item> The current global block number. +<item> The current offset in the entire directory - When viewing the + directory as a continuous file. +<item> The inode number of the directory itself. +<item> The indirection level - Whether it is a direct block (0), indirect + (1), etc. +</itemize> + +<sect1>cd +<p> +<tscreen><verb> +Syntax: cd [path] +</verb></tscreen> +The <tt>cd</> command is used in the usual meaning, like the global cd +command. +<itemize> +<item> If <em>path</> is not specified, the current directory entry is + followed. +<item> <em>path</> can be relative to the current directory. +<item> <em>path</> can also end up in a file, in which case the file inode + will be reached. +<item> Symbolic link (fast only, meanwhile) is automatically followed. +</itemize> + +<sect1>entry +<p> +<tscreen><verb> +Syntax: entry [entry_num] +</verb></tscreen> +The <tt>entry</> command sets <em>entry_num</> as the current directory +entry. + +<sect1>followinode +<p> +<tscreen><verb> +Syntax: followinode +</verb></tscreen> +The <tt>followinode</> command will move you to the inode pointed by the +current directory entry. + +<sect1>inode +<p> +<tscreen><verb> +Syntax: inode +</verb></tscreen> +The <tt>inode</> command will return you to the parent inode of the whole +directory listing. + +<sect1>next +<p> +<tscreen><verb> +Syntax: next [num] +</verb></tscreen> +The <tt>next</> command will pass to the next directory entry. +If <em>num</> is supplied, it will pass to the next <em>num</> entries. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [num] +</verb></tscreen> +The <tt>prev</> command will pass to the previous directory entry. +If <em>num</> is supplied, it will pass to the previous <em>num</> entries. + +<sect1>writedata +<p> +<tscreen><verb> +Syntax: writedata +</verb></tscreen> +The <tt>writedata</> command will write the current directory entry to the +disk. + +<sect><label id="block_bitmap">The block allocation bitmap +<p> +The <tt>block allocation bitmap</> of any block group can be reached from +the corresponding group descriptor. + +You will be offered a bit listing of the entire blocks in the group. The +current block will be highlighted and its number will be displayed in the +status window. + +A value of "1" means that the block is allocated, while a value of "0" +signals that it is free. The value is also interpreted in the status +window. You can use the usual <tt>next/prev</> commands, along with the +<tt>allocate/deallocate</> commands. + +<sect1>allocate +<p> +<tscreen><verb> +Syntax: allocate [num] +</verb></tscreen> +The <tt>allocate</> command allocates <em>num</> blocks, starting from the +highlighted position. If <em>num</> is not specified, <em>num=1</> is assumed. +Of-course, no actual change is made until you issue a <tt>writedata</> command. + +<sect1>deallocate +<p> +<tscreen><verb> +Syntax: deallocate [num] +</verb></tscreen> +The <tt>deallocate</> command deallocates <em>num</> blocks, starting from the +highlighted position. If <em>num</> is not specified, <em>num=1</> is assumed. +Of-course, no actual change is made until you issue a <tt>writedata</> command. +<tt>writedata</> command. + +<sect1>entry +<p> +<tscreen><verb> +Syntax: entry [entry_num] +</verb></tscreen> +The <tt>entry</> command sets the current highlighted block to +<em>entry_num</>. + +<sect1>next +<p> +<tscreen><verb> +Syntax: next [num] +</verb></tscreen> +The <tt>next</> command will pass to the next bit, which corresponds to the +next block. If <em>num</> is supplied, it will pass to the next <em>num</> +bits. + +<sect1>prev +<p> +<tscreen><verb> +Syntax: prev [num] +</verb></tscreen> +The <tt>prev</> command will pass to the previous bit, which corresponds to the +previous block. If <em>num</> is supplied, it will pass to the previous +<em>num</> bits. + +<sect>The inode allocation bitmap +<p> + +The <tt>inode allocation bitmap</> is very similar to the block allocation +bitmap explained above. It is also reached from the corresponding group +descriptor. Please refer to section <ref id="block_bitmap">. + +<sect>Filesystem size limitation +<p> + +While an ext2 filesystem has a size limit of <tt>4 TB</>, EXT2ED currently +<tt>can't</> handle filesystems which are <tt>bigger than 2 GB</>. + +I am sorry for the inconvenience. This will hopefully be fixed in future +releases. + +<sect>Copyright +<p> + +EXT2ED is Copyright (C) 1995 Gadi Oxman. + +EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and +welcome to copy, view and modify the sources. My only wish is that my +copyright presented above will be left and that a list of the bug fixes, +added features, etc, will be provided. + +The entire EXT2ED project is based, of-course, on the kernel sources. The +<tt>ext2.descriptors</> distributed with EXT2ED is a slightly modified +version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows +the original copyright: + +<tscreen><verb> +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +</verb></tscreen> + +<sect>Acknowledgments +<p> + +EXT2ED was constructed as a student project in the software +laboratory of the faculty of electrical-engineering in the +<tt>Technion - Israel's institute of technology</>. + +At first, I would like to thank <tt>Avner Lottem</> and <tt>Doctor Ilana +David</> for their interest and assistance in this project. + +I would also like to thank the following people, who were involved in the +design and implementation of the ext2 filesystem kernel code and support +utilities: +<itemize> +<item> <tt>Remy Card</> + + Who designed, implemented and maintains the ext2 filesystem kernel + code, and some of the ext2 utilities. Remy Card is also the author + of several helpful slides concerning the ext2 filesystem. + Specifically, he is the author of <tt>File Management in the Linux + Kernel</> and of <tt>The Second Extended File System - Current State, + Future Development</>. + +<item> <tt>Wayne Davison</> + + Who designed the ext2 filesystem. +<item> <tt>Stephen Tweedie</> + + Who helped designing the ext2 filesystem kernel code and wrote the + slides <tt>Optimizations in File Systems</>. +<item> <tt>Theodore Ts'o</> + + Who is the author of several ext2 utilities and of the ext2 library + <tt>libext2fs</> (which I didn't use, simply because I didn't know + it exists when I started to work on my project). +</itemize> + +Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the +<tt>Linux community</> for providing all of us with such a great operating +system. + +Please contact me in a case of bug report, suggestions, or just about +anything concerning EXT2ED. + +Enjoy, + +Gadi Oxman <tgud@tochnapc2.technion.ac.il> + +Haifa, August 95 +</article> \ No newline at end of file diff --git a/ext2ed/ext2.descriptors b/ext2ed/ext2.descriptors new file mode 100644 index 00000000..9d107faa --- /dev/null +++ b/ext2ed/ext2.descriptors @@ -0,0 +1,407 @@ +Extended 2 filesystem structure definitions for ext2ed. + +Most of this file is just copied from the ext2 main include file. + +My parser is very primitive - It only searches for the struct keywords, +and uses the variables in there. The rest of the file is just ignored. + +You will find at the end a few additional types which are not aviable in +the original include file, such as the types "file" and "dir". They have +no variables, but are necessary due to the way ext2ed binds C commands +to specific types. + +Gadi Oxman, 7/95 + +Here is the original copyright: + +/* + * linux/include/linux/ext2_fs.h + * + * Copyright (C) 1992, 1993, 1994 Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/include/linux/minix_fs.h + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + + +/* + * ACL structures + */ +struct ext2_acl_header /* Header of Access Control Lists */ +{ + unsigned long aclh_size; + unsigned long aclh_file_count; + unsigned long aclh_acle_count; + unsigned long aclh_first_acle; +}; + +struct ext2_acl_entry /* Access Control List Entry */ +{ + unsigned long acle_size; + unsigned short acle_perms; /* Access permissions */ + unsigned short acle_type; /* Type of entry */ + unsigned short acle_tag; /* User or group identity */ + unsigned short acle_pad1; + unsigned long acle_next; /* Pointer on next entry for the */ + /* same inode or on next free entry */ +}; + +/* + * Structure of a blocks group descriptor + */ + +struct ext2_group_desc +{ + unsigned long bg_block_bitmap; /* Blocks bitmap block */ + unsigned long bg_inode_bitmap; /* Inodes bitmap block */ + unsigned long bg_inode_table; /* Inodes table block */ + unsigned short bg_free_blocks_count; /* Free blocks count */ + unsigned short bg_free_inodes_count; /* Free inodes count */ + unsigned short bg_used_dirs_count; /* Directories count */ + unsigned short bg_pad; + unsigned long bg_reserved[0]; + unsigned long bg_reserved[1]; + unsigned long bg_reserved[2]; +}; + +/* + * Structure of an inode on the disk + */ +struct ext2_inode { + unsigned short i_mode; /* File mode */ + unsigned short i_uid; /* Owner Uid */ + unsigned long i_size; /* Size in bytes */ + unsigned long i_atime; /* Access time */ + unsigned long i_ctime; /* Creation time */ + unsigned long i_mtime; /* Modification time */ + unsigned long i_dtime; /* Deletion Time */ + unsigned short i_gid; /* Group Id */ + unsigned short i_links_count; /* Links count */ + unsigned long i_blocks; /* Blocks count */ + unsigned long i_flags; /* File flags */ + unsigned long l_i_reserved1; + unsigned long i_block[0]; /* Pointers to blocks */ + unsigned long i_block[1]; /* Pointers to blocks */ + unsigned long i_block[2]; /* Pointers to blocks */ + unsigned long i_block[3]; /* Pointers to blocks */ + unsigned long i_block[4]; /* Pointers to blocks */ + unsigned long i_block[5]; /* Pointers to blocks */ + unsigned long i_block[6]; /* Pointers to blocks */ + unsigned long i_block[7]; /* Pointers to blocks */ + unsigned long i_block[8]; /* Pointers to blocks */ + unsigned long i_block[9]; /* Pointers to blocks */ + unsigned long i_block[10]; /* Pointers to blocks */ + unsigned long i_block[11]; /* Pointers to blocks */ + unsigned long i_block[12]; /* Pointers to blocks */ + unsigned long i_block[13]; /* Pointers to blocks */ + unsigned long i_block[14]; /* Pointers to blocks */ + unsigned long i_version; /* File version (for NFS) */ + unsigned long i_file_acl; /* File ACL */ + unsigned long i_dir_acl; /* Directory ACL */ + unsigned long i_faddr; /* Fragment address */ + unsigned char l_i_frag; /* Fragment number */ + unsigned char l_i_fsize; /* Fragment size */ + unsigned short i_pad1; + unsigned long l_i_reserved2[0]; + unsigned long l_i_reserved2[1]; +}; + +/* + * Structure of the super block + */ +struct ext2_super_block { + unsigned long s_inodes_count; /* Inodes count */ + unsigned long s_blocks_count; /* Blocks count */ + unsigned long s_r_blocks_count; /* Reserved blocks count */ + unsigned long s_free_blocks_count; /* Free blocks count */ + unsigned long s_free_inodes_count; /* Free inodes count */ + unsigned long s_first_data_block; /* First Data Block */ + unsigned long s_log_block_size; /* Block size */ + long s_log_frag_size; /* Fragment size */ + unsigned long s_blocks_per_group; /* # Blocks per group */ + unsigned long s_frags_per_group; /* # Fragments per group */ + unsigned long s_inodes_per_group; /* # Inodes per group */ + unsigned long s_mtime; /* Mount time */ + unsigned long s_wtime; /* Write time */ + unsigned short s_mnt_count; /* Mount count */ + short s_max_mnt_count; /* Maximal mount count */ + unsigned short s_magic; /* Magic signature */ + unsigned short s_state; /* File system state */ + unsigned short s_errors; /* Behaviour when detecting errors */ + unsigned short s_pad; + unsigned long s_lastcheck; /* time of last check */ + unsigned long s_checkinterval; /* max. time between checks */ + unsigned long s_creator_os; /* OS */ + unsigned long s_rev_level; /* Revision level */ + unsigned short s_def_resuid; + unsigned short s_deg_resgid; + + unsigned long s_reserved[0]; /* Padding to the end of the block */ + unsigned long s_reserved[1]; + unsigned long s_reserved[2]; + unsigned long s_reserved[3]; + unsigned long s_reserved[4]; + unsigned long s_reserved[5]; + unsigned long s_reserved[6]; + unsigned long s_reserved[7]; + unsigned long s_reserved[8]; + unsigned long s_reserved[9]; + unsigned long s_reserved[10]; + unsigned long s_reserved[11]; + unsigned long s_reserved[12]; + unsigned long s_reserved[13]; + unsigned long s_reserved[14]; + unsigned long s_reserved[15]; + unsigned long s_reserved[16]; + unsigned long s_reserved[17]; + unsigned long s_reserved[18]; + unsigned long s_reserved[19]; + unsigned long s_reserved[20]; + unsigned long s_reserved[21]; + unsigned long s_reserved[22]; + unsigned long s_reserved[23]; + unsigned long s_reserved[24]; + unsigned long s_reserved[25]; + unsigned long s_reserved[26]; + unsigned long s_reserved[27]; + unsigned long s_reserved[28]; + unsigned long s_reserved[29]; + unsigned long s_reserved[30]; + unsigned long s_reserved[31]; + unsigned long s_reserved[32]; + unsigned long s_reserved[33]; + unsigned long s_reserved[34]; + unsigned long s_reserved[35]; + unsigned long s_reserved[36]; + unsigned long s_reserved[37]; + unsigned long s_reserved[38]; + unsigned long s_reserved[39]; + unsigned long s_reserved[40]; + unsigned long s_reserved[41]; + unsigned long s_reserved[42]; + unsigned long s_reserved[43]; + unsigned long s_reserved[44]; + unsigned long s_reserved[45]; + unsigned long s_reserved[46]; + unsigned long s_reserved[47]; + unsigned long s_reserved[48]; + unsigned long s_reserved[49]; + unsigned long s_reserved[50]; + unsigned long s_reserved[51]; + unsigned long s_reserved[52]; + unsigned long s_reserved[53]; + unsigned long s_reserved[54]; + unsigned long s_reserved[55]; + unsigned long s_reserved[56]; + unsigned long s_reserved[57]; + unsigned long s_reserved[58]; + unsigned long s_reserved[59]; + unsigned long s_reserved[60]; + unsigned long s_reserved[61]; + unsigned long s_reserved[62]; + unsigned long s_reserved[63]; + unsigned long s_reserved[64]; + unsigned long s_reserved[65]; + unsigned long s_reserved[66]; + unsigned long s_reserved[67]; + unsigned long s_reserved[68]; + unsigned long s_reserved[69]; + unsigned long s_reserved[70]; + unsigned long s_reserved[71]; + unsigned long s_reserved[72]; + unsigned long s_reserved[73]; + unsigned long s_reserved[74]; + unsigned long s_reserved[75]; + unsigned long s_reserved[76]; + unsigned long s_reserved[77]; + unsigned long s_reserved[78]; + unsigned long s_reserved[79]; + unsigned long s_reserved[80]; + unsigned long s_reserved[81]; + unsigned long s_reserved[82]; + unsigned long s_reserved[83]; + unsigned long s_reserved[84]; + unsigned long s_reserved[85]; + unsigned long s_reserved[86]; + unsigned long s_reserved[87]; + unsigned long s_reserved[88]; + unsigned long s_reserved[89]; + unsigned long s_reserved[90]; + unsigned long s_reserved[91]; + unsigned long s_reserved[92]; + unsigned long s_reserved[93]; + unsigned long s_reserved[94]; + unsigned long s_reserved[95]; + unsigned long s_reserved[96]; + unsigned long s_reserved[97]; + unsigned long s_reserved[98]; + unsigned long s_reserved[99]; + unsigned long s_reserved[100]; + unsigned long s_reserved[101]; + unsigned long s_reserved[102]; + unsigned long s_reserved[103]; + unsigned long s_reserved[104]; + unsigned long s_reserved[105]; + unsigned long s_reserved[106]; + unsigned long s_reserved[107]; + unsigned long s_reserved[108]; + unsigned long s_reserved[109]; + unsigned long s_reserved[110]; + unsigned long s_reserved[111]; + unsigned long s_reserved[112]; + unsigned long s_reserved[113]; + unsigned long s_reserved[114]; + unsigned long s_reserved[115]; + unsigned long s_reserved[116]; + unsigned long s_reserved[117]; + unsigned long s_reserved[118]; + unsigned long s_reserved[119]; + unsigned long s_reserved[120]; + unsigned long s_reserved[121]; + unsigned long s_reserved[122]; + unsigned long s_reserved[123]; + unsigned long s_reserved[124]; + unsigned long s_reserved[125]; + unsigned long s_reserved[126]; + unsigned long s_reserved[127]; + unsigned long s_reserved[128]; + unsigned long s_reserved[129]; + unsigned long s_reserved[130]; + unsigned long s_reserved[131]; + unsigned long s_reserved[132]; + unsigned long s_reserved[133]; + unsigned long s_reserved[134]; + unsigned long s_reserved[135]; + unsigned long s_reserved[136]; + unsigned long s_reserved[137]; + unsigned long s_reserved[138]; + unsigned long s_reserved[139]; + unsigned long s_reserved[140]; + unsigned long s_reserved[141]; + unsigned long s_reserved[142]; + unsigned long s_reserved[143]; + unsigned long s_reserved[144]; + unsigned long s_reserved[145]; + unsigned long s_reserved[146]; + unsigned long s_reserved[147]; + unsigned long s_reserved[148]; + unsigned long s_reserved[149]; + unsigned long s_reserved[150]; + unsigned long s_reserved[151]; + unsigned long s_reserved[152]; + unsigned long s_reserved[153]; + unsigned long s_reserved[154]; + unsigned long s_reserved[155]; + unsigned long s_reserved[156]; + unsigned long s_reserved[157]; + unsigned long s_reserved[158]; + unsigned long s_reserved[159]; + unsigned long s_reserved[160]; + unsigned long s_reserved[161]; + unsigned long s_reserved[162]; + unsigned long s_reserved[163]; + unsigned long s_reserved[164]; + unsigned long s_reserved[165]; + unsigned long s_reserved[166]; + unsigned long s_reserved[167]; + unsigned long s_reserved[168]; + unsigned long s_reserved[169]; + unsigned long s_reserved[170]; + unsigned long s_reserved[171]; + unsigned long s_reserved[172]; + unsigned long s_reserved[173]; + unsigned long s_reserved[174]; + unsigned long s_reserved[175]; + unsigned long s_reserved[176]; + unsigned long s_reserved[177]; + unsigned long s_reserved[178]; + unsigned long s_reserved[179]; + unsigned long s_reserved[180]; + unsigned long s_reserved[181]; + unsigned long s_reserved[182]; + unsigned long s_reserved[183]; + unsigned long s_reserved[184]; + unsigned long s_reserved[185]; + unsigned long s_reserved[186]; + unsigned long s_reserved[187]; + unsigned long s_reserved[188]; + unsigned long s_reserved[189]; + unsigned long s_reserved[190]; + unsigned long s_reserved[191]; + unsigned long s_reserved[192]; + unsigned long s_reserved[193]; + unsigned long s_reserved[194]; + unsigned long s_reserved[195]; + unsigned long s_reserved[196]; + unsigned long s_reserved[197]; + unsigned long s_reserved[198]; + unsigned long s_reserved[199]; + unsigned long s_reserved[200]; + unsigned long s_reserved[201]; + unsigned long s_reserved[202]; + unsigned long s_reserved[203]; + unsigned long s_reserved[204]; + unsigned long s_reserved[205]; + unsigned long s_reserved[206]; + unsigned long s_reserved[207]; + unsigned long s_reserved[208]; + unsigned long s_reserved[209]; + unsigned long s_reserved[210]; + unsigned long s_reserved[211]; + unsigned long s_reserved[212]; + unsigned long s_reserved[213]; + unsigned long s_reserved[214]; + unsigned long s_reserved[215]; + unsigned long s_reserved[216]; + unsigned long s_reserved[217]; + unsigned long s_reserved[218]; + unsigned long s_reserved[219]; + unsigned long s_reserved[220]; + unsigned long s_reserved[221]; + unsigned long s_reserved[222]; + unsigned long s_reserved[223]; + unsigned long s_reserved[224]; + unsigned long s_reserved[225]; + unsigned long s_reserved[226]; + unsigned long s_reserved[227]; + unsigned long s_reserved[228]; + unsigned long s_reserved[229]; + unsigned long s_reserved[230]; + unsigned long s_reserved[231]; + unsigned long s_reserved[232]; + unsigned long s_reserved[233]; + unsigned long s_reserved[234]; +}; + +The following is actually not used, due to the variable length of the +name field. EXT2ED handles directories through the type "dir" below. + +/* + * Structure of a directory entry + */ + +/* struct ext2_dir_entry { */ +/* + unsigned long inode; /* Inode number */ + unsigned short rec_len; /* Directory entry length */ + unsigned short name_len; /* Name length */ + char name[EXT2_NAME_LEN]; /* File name */ +}; +*/ + +struct file { +}; + +struct dir { +}; + +struct block_bitmap { +}; + +struct inode_bitmap { +}; diff --git a/ext2ed/ext2_com.c b/ext2ed/ext2_com.c new file mode 100644 index 00000000..b4d2a661 --- /dev/null +++ b/ext2ed/ext2_com.c @@ -0,0 +1,97 @@ +/* + +/usr/src/ext2ed/ext2_com.c + +A part of the extended file system 2 disk editor. + +-------------------------------------- +Extended-2 filesystem General commands +-------------------------------------- + +The commands here will be registered when we are editing an ext2 filesystem + +First written on: July 28 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + +void type_ext2___super (char *command_line) + +/* + +We are moving to the superblock - Just use setoffset and settype. The offset was gathered in the +initialization phase (but is constant - 1024). + +*/ + +{ + char buffer [80]; + + super_info.copy_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_super_block");dispatch (buffer); +} + +void type_ext2___cd (char *command_line) + +/* + +A global cd command - The path should start with /. + +We implement it through dispatching to our primitive functions. + +*/ + +{ + char temp [80],buffer [80],*ptr; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + if (buffer [0] != '/') { + wprintw (command_win,"Error - Use a full pathname (begin with '/')\n");refresh_command_win ();return; + } + + /* Note the various dispatches below - They should be intuitive if you know the ext2 filesystem structure */ + + dispatch ("super");dispatch ("group");dispatch ("inode");dispatch ("next");dispatch ("dir"); + if (buffer [1] != 0) { + sprintf (temp,"cd %s",buffer+1);dispatch (temp); + } +} + +void type_ext2___group (char *command_line) + +/* + +We go to the group descriptors. +First, we go to the first group descriptor in the main copy. +Then, we use the group's entry command to pass to another group. + +*/ + +{ + long group_num=0; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + group_num=atol (buffer); + } + + group_info.copy_num=0;group_info.group_num=0; + sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); + sprintf (buffer,"entry %ld",group_num);dispatch (buffer); +} diff --git a/ext2ed/ext2ed.conf b/ext2ed/ext2ed.conf new file mode 100644 index 00000000..4754d1ca --- /dev/null +++ b/ext2ed/ext2ed.conf @@ -0,0 +1,79 @@ +############################################################################## +# ext2ed.conf # +# # +# Configuration file for the extended 2 file system disk editor. # +############################################################################## + +# Ext2Descriptors is the location of the ext2 filesystem structure +# definitions. + + +Ext2Descriptors /var/lib/ext2ed/ext2.descriptors + + +# Using AlternateDescriptors you can declare additional structures. Those +# structures can contain only variables. Linking functions to the objects is +# possible only through source code additions. + + +AlternateDescriptors + + +# LogFile is the location of the log file. Actual changes to the filesystem +# are logged there. See also LogChanges. + + +LogFile /var/lib/ext2ed/ext2ed.log + + +# The following selects the default behavior when changes are made to the +# filesystem. When on, each change will be logged - Both the previous data +# and the new written data. + + +LogChanges on + + +# AllowChanges off will not allow ext2ed to do any changes to the +# filesystem - The "enablewrite" command will not work. When on, enablewrite +# will still have to be issued to allow write access. + + +AllowChanges on + + +# With this option you can choose whether ext2ed will allow read-only mode on +# a mounted filesystem. Read-Write mode is never allowed on a mounted +# filesystem. + + +AllowMountedRead on + + +# When ForceExt2 is set to on, the filesystem is assumed to be ext2 +# filesystem, despite the possibly corrupt superblock magic number reading. +# All the ext2 specific commands will be aviable despite the possible +# autodetection failture. + +ForceExt2 off + + +# Normally, the various filesystem parameters such as the block size and the +# total number of blocks are gathered from the ext2 filesystem itself. +# However, on a corrupt filesystem, ext2ed is unable to get the right +# parameters. In this case, they will be taken from here. See also +# ForceDefault. + + +DefaultBlockSize 1024 +DefaultTotalBlocks 2097151 # ~2 GB total size +DefaultBlocksInGroup 8192 + +# With ForceDefault on, you can force the use of the default parameters +# above. This is not recommended, as ext2ed will fallback by default to those +# parameters if it can't figure up the parameters from the filesystem itself. + + +ForceDefault off + + diff --git a/ext2ed/ext2ed.h b/ext2ed/ext2ed.h new file mode 100644 index 00000000..34d836f2 --- /dev/null +++ b/ext2ed/ext2ed.h @@ -0,0 +1,438 @@ + +/* + +/usr/src/ext2ed/ext2ed.h + +A part of the extended file system 2 disk editor. + +-------------------------------------- +Include file for the ext2 disk editor. +-------------------------------------- + +This file contains declarations which are needed by all the files in ext2ed. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#ifndef EXT2ED_EDITOR_H +#define EXT2ED_EDITOR_H + +/* + +----------------------- + User definable options +----------------------- + +*/ + +#ifndef VAR_DIR + #define VAR_DIR "/var/lib/ext2ed" /* The configuration file will be searched here */ +#endif + +#define DEBUG /* Activate self-sanity checks */ + +#include <linux/ext2_fs.h> /* Main kernel ext2 include file */ +#include <linux/stat.h> + +#ifdef OLD_NCURSES /* The ncurses interface */ + #include <ncurses/ncurses.h> +#else + #include <ncurses/curses.h> +#endif + +#define MAX_FIELDS 400 + +#define MAX_COMMAND_LINE 81 +#define MAX_COMMANDS_NUM 30 /* Maximum number of commands of one type */ +#define REMEMBER_COUNT 30 /* Object memory size */ + +/* + The user screen consists of four parts: + + 1. Title window (title_win). + 2. Show (status) window (show_win). + 3. Main show pad (show_pad). + 4. Command window (command_win). + +*/ + +/* + + The show pad is mapped to the space left between the other three windows. + + If you wondered why ext2ed grabs so memory, the answer is probably below - I wanted to treat + the virtual display as infinite. Decrease the following for more realistic memory consumption. + +*/ + +#define SHOW_PAD_LINES 3000 +#define SHOW_PAD_COLS (COLS > 140 ? COLS : 140) + +#define COMMAND_WIN_LINES 6 /* Change this to your preferences */ +#define TITLE_WIN_LINES 3 +#define SHOW_WIN_LINES 3 + +#define HEX 1 +#define TEXT 2 + +#ifndef EXT2_PRE_02B_MAGIC + #define EXT2_PRE_02B_MAGIC 0xEF51 +#endif + + +typedef void (*PF) (char *); /* Used to point to the dispatched functions */ + +struct struct_commands { /* Holds commands of an object */ + int last_command; + char *names [MAX_COMMANDS_NUM]; + char *descriptions [MAX_COMMANDS_NUM]; + PF callback [MAX_COMMANDS_NUM]; +}; + +struct struct_descriptor { /* Describes an object */ + unsigned long length; + unsigned char name [60]; + unsigned short fields_num; + unsigned char field_names [MAX_FIELDS][80]; + unsigned short field_lengths [MAX_FIELDS]; + unsigned short field_positions [MAX_FIELDS]; + struct struct_commands type_commands; + struct struct_descriptor *prev,*next; +}; + +struct struct_type_data { /* The object's data is usually here */ + long offset_in_block; + + union union_type_data { /* Format it in various ways */ + char buffer [EXT2_MAX_BLOCK_SIZE]; + struct ext2_acl_header t_ext2_acl_header; + struct ext2_acl_entry t_ext2_acl_entry; + struct ext2_group_desc t_ext2_group_desc; + struct ext2_inode t_ext2_inode; + struct ext2_super_block t_ext2_super_block; + struct ext2_dir_entry t_ext2_dir_entry; + } u; +}; + +struct struct_file_system_info { /* Important information about the filesystem */ + unsigned long long file_system_size; + unsigned long super_block_offset; + unsigned long first_group_desc_offset; + unsigned long groups_count; + unsigned long inodes_per_block; + unsigned long blocks_per_group; /* The name is misleading; beware */ + unsigned long no_blocks_in_group; + unsigned short block_size; + struct ext2_super_block super_block; +}; + +struct struct_file_info { /* Used to handle files and directories */ + + struct ext2_inode *inode_ptr; + + long inode_offset; + long global_block_num,global_block_offset; + long block_num,blocks_count; + long file_offset,file_length; + long level; + unsigned char buffer [EXT2_MAX_BLOCK_SIZE]; + long offset_in_block; + + int display; + /* The following is used if the file is a directory */ + + long dir_entry_num,dir_entries_count; + long dir_entry_offset; +}; + +struct struct_super_info { /* Used to handle the superblock */ + unsigned long copy_num; +}; + +struct struct_group_info { /* Used to handle the group descriptors */ + unsigned long copy_num; + unsigned long group_num; +}; + +struct struct_block_bitmap_info { /* Used in blockbitmap_com.c */ + unsigned long entry_num; + unsigned long group_num; +}; + +struct struct_inode_bitmap_info { /* Used in inodebitmap_com.c */ + unsigned long entry_num; + unsigned long group_num; +}; + +struct struct_remember_lifo { /* Implements the objects circular memory */ + long entries_count; + + long offset [REMEMBER_COUNT]; + struct struct_descriptor *type [REMEMBER_COUNT]; + char name [REMEMBER_COUNT][80]; +}; + +struct struct_pad_info { /* Used to zoom into the pad window */ + int display_lines,display_cols; + int line,col; + int max_line,max_col; + int disable_output; +}; + +/* Global variables (defined mostly in main.c) */ + +/* Configurable variables (Through configuration file) */ + +extern char AlternateDescriptors [200]; +extern char Ext2Descriptors [200]; +extern char LogFile [200]; +extern int LogChanges; +extern int AllowChanges; +extern int AllowMountedRead; +extern int ForceExt2; +extern int DefaultBlockSize; +extern unsigned long DefaultTotalBlocks; +extern unsigned long DefaultBlocksInGroup; +extern int ForceDefault; + +extern char device_name [80]; +extern char last_command_line [80]; +extern FILE *device_handle; +extern long device_offset; +extern int mounted; + +extern short block_size; +extern struct struct_commands general_commands; +extern struct struct_commands ext2_commands; +extern struct struct_descriptor *first_type; +extern struct struct_descriptor *last_type; +extern struct struct_descriptor *current_type; +extern struct struct_type_data type_data; +extern struct struct_file_system_info file_system_info; +extern struct struct_file_info file_info,first_file_info; +extern struct struct_group_info group_info; +extern struct struct_super_info super_info; +extern struct struct_block_bitmap_info block_bitmap_info; +extern struct struct_inode_bitmap_info inode_bitmap_info; +extern struct struct_remember_lifo remember_lifo; +extern struct struct_pad_info show_pad_info; +extern int write_access; + +extern int redraw_request; +extern char lines_s [80]; +extern char cols_s [80]; + + +/* init.c */ + +extern int init (void); +extern void prepare_to_close (void); +extern int set_struct_descriptors (char *file_name); +extern void free_struct_descriptors (void); +extern struct struct_descriptor *add_new_descriptor (char *name); +extern void add_new_variable (struct struct_descriptor *descriptor,char *v_type,char *v_name); +extern void fill_type_commands (struct struct_descriptor *ptr); +extern void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback); +extern void free_user_commands (struct struct_commands *ptr); +extern int set_file_system_info (void); +extern int process_configuration_file (void); +extern void add_general_commands (void); +extern void add_ext2_general_commands (void); +extern void check_mounted (char *name); + +int get_next_option (FILE *fp,char *option,char *value); +void init_readline (void); +void init_signals (void); +void signal_SIGWINCH_handler (int sig_num); +void signal_SIGTERM_handler (int sig_num); +void signal_SIGSEGV_handler (int sig_num); + +/* general_com.c */ + +/* General commands which are aviable always */ + +extern void help (char *command_line); +extern void set (char *command_line); +extern void set_device (char *command_line); +extern void set_offset (char *command_line); +extern void set_type (char *command_line); +extern void show (char *command_line); +extern void pgup (char *command_line); +extern void pgdn (char *command_line); +extern void redraw (char *command_line); +extern void remember (char *command_line); +extern void recall (char *command_line); +extern void cd (char *command_line); +extern void enable_write (char *command_line); +extern void disable_write (char *command_line); +extern void write_data (char *command_line); +extern void next (char *command_line); +extern void prev (char *command_line); + +void hex_set (char *command_line); +void detailed_help (char *text); + + +/* ext2_com.c */ + +/* Extended2 filesystem genereal commands - Aviable only when editing an + ext2 filesystem */ + +extern void type_ext2___super (char *command_line); +extern void type_ext2___group (char *command_line); +extern void type_ext2___cd (char *command_line); + + +/* main.c */ + +extern int version_major,version_minor; +extern char revision_date [80]; +extern char email_address [80]; + +#ifdef DEBUG +extern void internal_error (char *description,char *source_name,char *function_name); +#endif + +void parser (void); +extern int dispatch (char *command_line); +char *parse_word (char *source,char *dest); +char *complete_command (char *text,int state); +char *dupstr (char *src); + + + +/* disk.c */ + +extern int load_type_data (void); +extern int write_type_data (void); +extern int low_read (unsigned char *buffer,unsigned long length,unsigned long offset); +extern int low_write (unsigned char *buffer,unsigned long length,unsigned long offset); +extern int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset); + +/* file_com.c */ + +extern int init_file_info (void); +extern void type_file___show (char *command_line); +extern void type_file___inode (char *command_line); +extern void type_file___display (char *command_line); +extern void type_file___prev (char *command_line); +extern void type_file___next (char *command_line); +extern void type_file___offset (char *command_line); +extern void type_file___prevblock (char *command_line); +extern void type_file___nextblock (char *command_line); +extern void type_file___block (char *command_line); +extern void type_file___remember (char *command_line); +extern void type_file___set (char *command_line); +extern void type_file___writedata (char *command_line); + +extern long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr); +extern long return_indirect (long table_block,long block_num); +extern long return_dindirect (long table_block,long block_num); +extern long return_tindirect (long table_block,long block_num); + +void file_show_hex (void); +void file_show_text (void); +void show_status (void); + +/* inode_com.c */ + +extern void type_ext2_inode___next (char *command_line); +extern void type_ext2_inode___prev (char *command_line); +extern void type_ext2_inode___show (char *command_line); +extern void type_ext2_inode___group (char *command_line); +extern void type_ext2_inode___entry (char *command_line); +extern void type_ext2_inode___file (char *command_line); +extern void type_ext2_inode___dir (char *command_line); + +extern long inode_offset_to_group_num (long inode_offset); +extern long int inode_offset_to_inode_num (long inode_offset); +extern long int inode_num_to_inode_offset (long inode_num); + +/* dir_com.c */ + +extern int init_dir_info (struct struct_file_info *info); +extern void type_dir___show (char *command_line); +extern void type_dir___inode (char *command_line); +extern void type_dir___pgdn (char *command_line); +extern void type_dir___pgup (char *command_line); +extern void type_dir___prev (char *command_line); +extern void type_dir___next (char *command_line); +extern void type_dir___followinode (char *command_line); +extern void type_dir___remember (char *command_line); +extern void type_dir___cd (char *command_line); +extern void type_dir___entry (char *command_line); +extern void type_dir___writedata (char *command_line); +extern void type_dir___set (char *command_line); + +#define HEX 1 +#define TEXT 2 + +#define ABORT 0 +#define CONTINUE 1 +#define FOUND 2 + +struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status); +int action_count (struct struct_file_info *info); +void show_dir_status (void); +long count_dir_entries (void); +int action_name (struct struct_file_info *info); +int action_entry_num (struct struct_file_info *info); +int action_show (struct struct_file_info *info); + +/* super_com.c */ + +extern void type_ext2_super_block___show (char *command_line); +extern void type_ext2_super_block___gocopy (char *command_line); +extern void type_ext2_super_block___setactivecopy (char *command_line); + +/* group_com.c */ + +extern void type_ext2_group_desc___next (char *command_line); +extern void type_ext2_group_desc___prev (char *command_line); +extern void type_ext2_group_desc___entry (char *command_line); +extern void type_ext2_group_desc___show (char *command_line); +extern void type_ext2_group_desc___inode (char *command_line); +extern void type_ext2_group_desc___gocopy (char *command_line); +extern void type_ext2_group_desc___blockbitmap (char *command_line); +extern void type_ext2_group_desc___inodebitmap (char *command_line); +extern void type_ext2_group_desc___setactivecopy (char *command_line); + +/* blockbitmap_com.c */ + +extern void type_ext2_block_bitmap___show (char *command_line); +extern void type_ext2_block_bitmap___entry (char *command_line); +extern void type_ext2_block_bitmap___next (char *command_line); +extern void type_ext2_block_bitmap___prev (char *command_line); +extern void type_ext2_block_bitmap___allocate (char *command_line); +extern void type_ext2_block_bitmap___deallocate (char *command_line); +void allocate_block (long entry_num); +void deallocate_block (long entry_num); + +/* inodebitmap_bom.c */ + +extern void type_ext2_inode_bitmap___show (char *command_line); +extern void type_ext2_inode_bitmap___entry (char *command_line); +extern void type_ext2_inode_bitmap___next (char *command_line); +extern void type_ext2_inode_bitmap___prev (char *command_line); +extern void type_ext2_inode_bitmap___allocate (char *command_line); +extern void type_ext2_inode_bitmap___deallocate (char *command_line); +void allocate_inode (long entry_num); +void deallocate_inode (long entry_num); + +/* win.c */ + +extern WINDOW *title_win,*show_win,*command_win,*show_pad; + +extern void init_windows (void); +extern void refresh_title_win (void); +extern void refresh_show_win (void); +extern void refresh_show_pad (void); +extern void refresh_command_win (void); +extern void show_info (void); +extern void redraw_all (void); +extern void close_windows (void); + +#endif /* EXT2ED_EDITOR_H */ \ No newline at end of file diff --git a/ext2ed/file_com.c b/ext2ed/file_com.c new file mode 100644 index 00000000..898df657 --- /dev/null +++ b/ext2ed/file_com.c @@ -0,0 +1,564 @@ +/* + +/usr/src/ext2ed/file_com.c + +A part of the extended file system 2 disk editor. + +---------------------------- +Commands which handle a file +---------------------------- + +First written on: April 18 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + +int init_file_info (void) + +{ + struct ext2_inode *ptr; + + ptr=&type_data.u.t_ext2_inode; + + file_info.inode_ptr=ptr; + file_info.inode_offset=device_offset; + + file_info.global_block_num=ptr->i_block [0]; + file_info.global_block_offset=ptr->i_block [0]*file_system_info.block_size; + file_info.block_num=0; + file_info.blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size; + file_info.file_offset=0; + file_info.file_length=ptr->i_size; + file_info.level=0; + file_info.offset_in_block=0; + + file_info.display=HEX; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + return (1); +} + + +void type_file___inode (char *command_line) + +{ + dispatch ("settype ext2_inode"); +} + +void type_file___show (char *command_line) + +{ + if (file_info.display==HEX) + file_show_hex (); + if (file_info.display==TEXT) + file_show_text (); +} + +void type_file___nextblock (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + block_offset*=atol (buffer); + } + + if (file_info.block_num+block_offset >= file_info.blocks_count) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num+=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___next (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (file_info.offset_in_block+offset < file_system_info.block_size) { + file_info.offset_in_block+=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___offset (char *command_line) + +{ + unsigned long offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset=atol (buffer); + } + else { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + if (offset < file_system_info.block_size) { + file_info.offset_in_block=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___prev (char *command_line) + +{ + int offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (file_info.offset_in_block-offset >= 0) { + file_info.offset_in_block-=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void type_file___prevblock (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + block_offset*=atol (buffer); + } + + if (file_info.block_num-block_offset < 0) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num-=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___block (char *command_line) + +{ + long block_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + block_offset=atol (buffer); + + if (block_offset < 0 || block_offset >= file_info.blocks_count) { + wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win); + return; + } + + file_info.block_num=block_offset; + file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info); + file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size; + file_info.file_offset=file_info.block_num*file_system_info.block_size; + + low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___display (char *command_line) + +{ + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) + strcpy (buffer,"hex"); + else + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"hex")==0) { + wprintw (command_win,"Display set to hex\n");wrefresh (command_win); + file_info.display=HEX; + sprintf (buffer,"show");dispatch (buffer); + } + + else if (strcasecmp (buffer,"text")==0) { + wprintw (command_win,"Display set to text\n");wrefresh (command_win); + file_info.display=TEXT; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win); + } +} + +void file_show_hex (void) + +{ + long offset=0,l,i; + unsigned char *ch_ptr; + + /* device_offset and type_data points to the inode */ + + show_pad_info.line=0; + + wmove (show_pad,0,0); + ch_ptr=file_info.buffer; + for (l=0;l<file_system_info.block_size/16;l++) { + if (file_info.file_offset+offset>file_info.file_length-1) break; + wprintw (show_pad,"%08ld : ",offset); + for (i=0;i<16;i++) { + + if (file_info.file_offset+offset+i>file_info.file_length-1) { + wprintw (show_pad," "); + } + + else { + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + if (ch_ptr [i]>=' ' && ch_ptr [i]<='z') + wprintw (show_pad,"%c",ch_ptr [i]); + else + wprintw (show_pad,"."); + + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_NORMAL); + } + } + + wprintw (show_pad," "); + for (i=0;i<16;i++) { + if (file_info.file_offset+offset+i>file_info.file_length-1) break; + if (file_info.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + wprintw (show_pad,"%02x",ch_ptr [i]); + + if (file_info.offset_in_block==offset+i) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + wprintw (show_pad," "); + + } + + wprintw (show_pad,"\n"); + offset+=i; + ch_ptr+=i; + } + + show_pad_info.max_line=l-1; + + refresh_show_pad (); + + show_status (); +} + +void file_show_text (void) + +{ + long offset=0,last_offset,l=0,cols=0; + unsigned char *ch_ptr; + + /* device_offset and type_data points to the inode */ + + show_pad_info.line=0; + wmove (show_pad,0,0); + ch_ptr=file_info.buffer; + + last_offset=file_system_info.block_size-1; + + if (file_info.file_offset+last_offset > file_info.file_length-1) + last_offset=file_info.file_length-1-file_info.file_offset; + + while ( (offset <= last_offset) && l<SHOW_PAD_LINES) { + + if (cols==SHOW_PAD_COLS-1) { + wprintw (show_pad,"\n"); + l++;cols=0; + } + + + if (file_info.offset_in_block==offset) + wattrset (show_pad,A_REVERSE); + + if (*ch_ptr >= ' ' && *ch_ptr <= 'z') + wprintw (show_pad,"%c",*ch_ptr); + + + else { + if (*ch_ptr == 0xa) { + wprintw (show_pad,"\n"); + l++;cols=0; + } + + else if (*ch_ptr == 0x9) + wprintw (show_pad," "); + + else + wprintw (show_pad,"."); + } + + if (file_info.offset_in_block==offset) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + + offset++;cols++;ch_ptr++; + } + + wprintw (show_pad,"\n"); + show_pad_info.max_line=l; + + refresh_show_pad (); + + show_status (); +} + +void show_status (void) + +{ + long inode_num; + + werase (show_win);wmove (show_win,0,0); + wprintw (show_win,"File contents. Block %ld. ",file_info.global_block_num); + wprintw (show_win,"File block %ld of %ld. ",file_info.block_num,file_info.blocks_count-1); + wprintw (show_win,"File Offset %ld of %ld.",file_info.file_offset,file_info.file_length-1); + + wmove (show_win,1,0); + inode_num=inode_offset_to_inode_num (file_info.inode_offset); + wprintw (show_win,"File inode %ld. Indirection level %ld.",inode_num,file_info.level); + + refresh_show_win (); +} + +void type_file___remember (char *command_line) + +{ + int found=0; + long entry_num; + char *ptr,buffer [80]; + struct struct_descriptor *descriptor_ptr; + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,"ext2_inode")==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=descriptor_ptr; + strcpy (remember_lifo.name [entry_num],buffer); + + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer); + wrefresh (command_win); +} + +void type_file___set (char *command_line) + +{ + unsigned char tmp; + char *ptr,buffer [80],*ch_ptr; + int mode=HEX; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return; + } + + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"text")==0) { + mode=TEXT; + strcpy (buffer,ptr); + } + + else if (strcasecmp (buffer,"hex")==0) { + mode=HEX; + ptr=parse_word (ptr,buffer); + } + + if (*buffer==0) { + wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return; + } + + if (mode==HEX) { + do { + tmp=(unsigned char) strtol (buffer,NULL,16); + file_info.buffer [file_info.offset_in_block]=tmp; + file_info.offset_in_block++; + ptr=parse_word (ptr,buffer); + if (file_info.offset_in_block==file_system_info.block_size) { + if (*ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + file_info.offset_in_block--; + } + } while (*buffer) ; + } + + else { + ch_ptr=buffer; + while (*ch_ptr) { + tmp=(unsigned char) *ch_ptr++; + file_info.buffer [file_info.offset_in_block]=tmp; + file_info.offset_in_block++; + if (file_info.offset_in_block==file_system_info.block_size) { + if (*ch_ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + file_info.offset_in_block--; + } + } + } + + strcpy (buffer,"show");dispatch (buffer); +} + +void type_file___writedata (char *command_line) + +{ + low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset); + return; +} + +long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr) + +{ + long last_direct,last_indirect,last_dindirect; + + last_direct=EXT2_NDIR_BLOCKS-1; + last_indirect=last_direct+file_system_info.block_size/4; + last_dindirect=last_indirect+(file_system_info.block_size/4)*(file_system_info.block_size/4); + + if (file_block <= last_direct) { + file_info_ptr->level=0; + return (file_info_ptr->inode_ptr->i_block [file_block]); + } + + if (file_block <= last_indirect) { + file_info_ptr->level=1; + file_block=file_block-last_direct-1; + return (return_indirect (file_info_ptr->inode_ptr->i_block [EXT2_IND_BLOCK],file_block)); + } + + if (file_block <= last_dindirect) { + file_info_ptr->level=2; + file_block=file_block-last_indirect-1; + return (return_dindirect (file_info_ptr->inode_ptr->i_block [EXT2_DIND_BLOCK],file_block)); + } + + file_info_ptr->level=3; + file_block=file_block-last_dindirect-1; + return (return_tindirect (file_info_ptr->inode_ptr->i_block [EXT2_TIND_BLOCK],file_block)); +} + +long return_indirect (long table_block,long block_num) + +{ + long block_table [EXT2_MAX_BLOCK_SIZE/4]; + + low_read ((char *) block_table,file_system_info.block_size,table_block*file_system_info.block_size); + return (block_table [block_num]); +} + +long return_dindirect (long table_block,long block_num) + +{ + long f_indirect; + + f_indirect=block_num/(file_system_info.block_size/4); + f_indirect=return_indirect (table_block,f_indirect); + return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4))); +} + +long return_tindirect (long table_block,long block_num) + +{ + long s_indirect; + + s_indirect=block_num/((file_system_info.block_size/4)*(file_system_info.block_size/4)); + s_indirect=return_indirect (table_block,s_indirect); + return (return_dindirect (s_indirect,block_num%((file_system_info.block_size/4)*(file_system_info.block_size/4)))); +} diff --git a/ext2ed/general_com.c b/ext2ed/general_com.c new file mode 100644 index 00000000..a8ebdc3a --- /dev/null +++ b/ext2ed/general_com.c @@ -0,0 +1,748 @@ +/* + +/usr/src/ext2ed/general_com.c + +A part of the extended file system 2 disk editor. + +--------------------- +General user commands +--------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + +void help (char *command_line) + +{ + int i,max_line=0; + char argument [80],*ptr; + + werase (show_pad);wmove (show_pad,0,0); + + ptr=parse_word (command_line,argument); + + if (*ptr!=0) { + ptr=parse_word (ptr,argument); + if (*argument!=0) { + detailed_help (argument); + return; + } + } + + if (current_type!=NULL) { + + wprintw (show_pad,"Type %s specific commands:\n",current_type->name);max_line++; + + if (current_type->type_commands.last_command==-1) { + wprintw (show_pad,"\nnone\n");max_line+=2; + } + else + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",current_type->type_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + } + + wprintw (show_pad,"\n\n");max_line+=2; + } + + if (ext2_commands.last_command != -1) { + wprintw (show_pad,"ext2 filesystem general commands: \n");max_line++; + for (i=0;i<=ext2_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",ext2_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + + } + wprintw (show_pad,"\n\n");max_line+=2; + } + + wprintw (show_pad,"General commands: \n"); + + for (i=0;i<=general_commands.last_command;i++) { + if (i%5==0) { + wprintw (show_pad,"\n");max_line++; + } + wprintw (show_pad,"%-13s",general_commands.names [i]); + if (i%5!=4) + wprintw (show_pad,"; "); + } + + wprintw (show_pad,"\n\n");max_line+=2; + + wprintw (show_pad,"EXT2ED ver %d.%d (%s)\n",version_major,version_minor,revision_date); + wprintw (show_pad,"Copyright (C) 1995 Gadi Oxman\n"); + wprintw (show_pad,"EXT2ED is hereby placed under the terms of the GNU General Public License.\n\n"); + wprintw (show_pad,"EXT2ED was programmed as a student project in the software laboratory\n"); + wprintw (show_pad,"of the faculty of electrical engineering in the\n"); + wprintw (show_pad,"Technion - Israel Institute of Technology\n"); + wprintw (show_pad,"with the guide of Avner Lottem and Dr. Ilana David.\n"); + + max_line+=6; + + wprintw (show_pad,"\n\n");max_line+=2; + + wprintw (show_pad,"Please feel free to mail me at (currently) %s\n",email_address); + wprintw (show_pad,"with any commet, suggestion, and of-course, bug report concerning EXT2ED.\n"); + + max_line+=2; + + show_pad_info.line=0;show_pad_info.max_line=max_line; + + werase (show_win);wmove (show_win,0,0); + wprintw (show_win,"EXT2ED help"); + + refresh_show_win (); + refresh_show_pad (); +} + +void detailed_help (char *text) + +{ + int i; + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (strcmp (current_type->type_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,current_type->type_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + for (i=0;i<=ext2_commands.last_command;i++) { + if (strcmp (ext2_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,ext2_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + for (i=0;i<=general_commands.last_command;i++) { + if (strcmp (general_commands.names [i],text)==0) { + wprintw (show_pad,"%s - %s\n",text,general_commands.descriptions [i]); + refresh_show_pad ();return; + } + } + + if (strcmp ("quit",text)==0) { + wprintw (show_pad,"quit - Exists EXT2ED"); + refresh_show_pad ();return; + } + + wprintw (show_pad,"Error - Command %s not aviable now\n",text); + refresh_show_pad ();return; +} + + + +void set_device (char *command_line) + +{ + char *ptr,new_device [80]; + + ptr=parse_word (command_line,new_device); + if (*ptr==0) { + wprintw (command_win,"Error - Device name not specified\n"); + refresh_command_win ();return; + } + parse_word (ptr,new_device); + check_mounted (new_device); + if (mounted && !AllowMountedRead) { + wprintw (command_win,"Error - Filesystem is mounted, aborting\n"); + wprintw (command_win,"You may wish to use the AllowMountedRead on configuration option\n"); + refresh_command_win ();return; + } + + if (mounted && AllowMountedRead) { + wprintw (command_win,"Warning - Filesystem is mounted. Displayed data may be unreliable.\n"); + refresh_command_win (); + } + + if (device_handle!=NULL) + fclose (device_handle); + + if ( (device_handle=fopen (new_device,"rb"))==NULL) { + wprintw (command_win,"Error - Can not open device %s\n",new_device);refresh_command_win (); + return; + } + else { + strcpy (device_name,new_device); + write_access=0; /* Write access disabled */ + current_type=NULL; /* There is no type now */ + remember_lifo.entries_count=0; /* Empty Object memory */ + free_user_commands (&ext2_commands); /* Free filesystem specific objects */ + free_struct_descriptors (); + if (!set_file_system_info ()) { /* Error while getting info --> abort */ + free_user_commands (&ext2_commands); + free_struct_descriptors (); + fclose (device_handle); + device_handle=NULL; /* Notice that our device is still not set up */ + device_offset=-1; + return; + } + if (*AlternateDescriptors) /* Check if user defined objects exist */ + set_struct_descriptors (AlternateDescriptors); + dispatch ("setoffset 0"); + dispatch ("help"); /* Show help screen */ + wprintw (command_win,"Device changed to %s",device_name);refresh_command_win (); + } +} + +void set_offset (char *command_line) + +{ + long mult=1; + long new_offset; + char *ptr,new_offset_buffer [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,new_offset_buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,new_offset_buffer); + + if (strcmp (new_offset_buffer,"block")==0) { + mult=file_system_info.block_size; + ptr=parse_word (ptr,new_offset_buffer); + } + + if (strcmp (new_offset_buffer,"type")==0) { + if (current_type==NULL) { + wprintw (command_win,"Error - No type set\n");refresh_command_win (); + return; + } + + mult=current_type->length; + ptr=parse_word (ptr,new_offset_buffer); + } + + if (*new_offset_buffer==0) { + wprintw (command_win,"Error - No offset specified\n");refresh_command_win (); + return; + } + + if (new_offset_buffer [0]=='+') { + if (device_offset==-1) { + wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win (); + return; + } + new_offset=device_offset+atol (new_offset_buffer+1)*mult; + } + + else if (new_offset_buffer [0]=='-') { + if (device_offset==-1) { + wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win (); + return; + } + new_offset=device_offset-atol (new_offset_buffer+1)*mult; + if (new_offset<0) new_offset=0; + } + + else + new_offset=atol (new_offset_buffer)*mult; + + if ( (fseek (device_handle,new_offset,SEEK_SET))==-1) { + wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",new_offset,device_name); + refresh_command_win (); + return; + }; + device_offset=new_offset; + wprintw (command_win,"Device offset changed to %ld\n",device_offset);refresh_command_win (); + load_type_data (); + type_data.offset_in_block=0; +} + +void set (char *command_line) + +{ + unsigned short *int_ptr; + unsigned char *char_ptr; + unsigned long *long_ptr,offset=0; + int i,found=0; + char *ptr,buffer [80],variable [80],value [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if (current_type==NULL) { + hex_set (command_line); + return; + } + + ptr=parse_word (command_line,buffer); + if (ptr==NULL || *ptr==0) { + wprintw (command_win,"Error - Missing arguments\n");refresh_command_win (); + return; + } + parse_word (ptr,buffer); + ptr=strchr (buffer,'='); + if (ptr==NULL) { + wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return; + } + strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0; + strcpy (value,++ptr); + + if (current_type==NULL) { + wprintw (command_win,"Sorry, not yet supported\n");refresh_command_win ();return; + } + + for (i=0;i<current_type->fields_num && !found;i++) { + if (strcmp (current_type->field_names [i],variable)==0) { + found=1; + ptr=type_data.u.buffer+offset; + switch (current_type->field_lengths [i]) { + case 1: + char_ptr=(unsigned char *) ptr; + *char_ptr=(char) atoi (value); + wprintw (command_win,"Variable %s set to %u\n",variable,*char_ptr);refresh_command_win (); + break; + case 2: + int_ptr=(unsigned short *) ptr; + *int_ptr=atoi (value); + wprintw (command_win,"Variable %s set to %u\n",variable,*int_ptr);refresh_command_win (); + break; + + case 4: + long_ptr=(unsigned long *) ptr; + *long_ptr=atol (value); + wprintw (command_win,"Variable %s set to %lu\n",variable,*long_ptr);refresh_command_win (); + break; + } + } + offset+=current_type->field_lengths [i]; + } + if (found) + dispatch ("show"); + else { + wprintw (command_win,"Error - Variable %s not found\n",variable); + refresh_command_win (); + } +} + +void hex_set (char *command_line) + +{ + unsigned char tmp; + char *ptr,buffer [80],*ch_ptr; + int mode=HEX; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return; + } + + ptr=parse_word (ptr,buffer); + + if (strcasecmp (buffer,"text")==0) { + mode=TEXT; + strcpy (buffer,ptr); + } + + else if (strcasecmp (buffer,"hex")==0) { + mode=HEX; + ptr=parse_word (ptr,buffer); + } + + if (*buffer==0) { + wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return; + } + + if (mode==HEX) { + do { + tmp=(unsigned char) strtol (buffer,NULL,16); + type_data.u.buffer [type_data.offset_in_block]=tmp; + type_data.offset_in_block++; + ptr=parse_word (ptr,buffer); + if (type_data.offset_in_block==file_system_info.block_size) { + if (*ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + type_data.offset_in_block--; + } + } while (*buffer) ; + } + + else { + ch_ptr=buffer; + while (*ch_ptr) { + tmp=(unsigned char) *ch_ptr++; + type_data.u.buffer [type_data.offset_in_block]=tmp; + type_data.offset_in_block++; + if (type_data.offset_in_block==file_system_info.block_size) { + if (*ch_ptr) { + wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n"); + refresh_command_win (); + } + type_data.offset_in_block--; + } + } + } + + strcpy (buffer,"show");dispatch (buffer); +} + + + +void set_type (char *command_line) + +{ + struct struct_descriptor *descriptor_ptr; + char *ptr,buffer [80],tmp_buffer [80]; + short found=0; + + if (!load_type_data ()) + return; + + ptr=parse_word (command_line,buffer); + parse_word (ptr,buffer); + + if (strcmp (buffer,"none")==0 || strcmp (buffer,"hex")==0) { + wprintw (command_win,"Data will be shown as hex dump\n");refresh_command_win (); + current_type=NULL; + sprintf (tmp_buffer,"show");dispatch (tmp_buffer); + return; + } + + descriptor_ptr=first_type; + while (descriptor_ptr!=NULL && !found) { + if (strcmp (descriptor_ptr->name,buffer)==0) + found=1; + else + descriptor_ptr=descriptor_ptr->next; + } + if (found) { + wprintw (command_win,"Structure type set to %s\n",buffer);refresh_command_win (); + current_type=descriptor_ptr; + sprintf (tmp_buffer,"show");dispatch (tmp_buffer); + } + else { + wprintw (command_win,"Error - %s is not a valid type\n",buffer);refresh_command_win (); + } +} + + +void show (char *command_line) + +{ + unsigned int i,l,temp_int; + unsigned long offset=0,temp_long; + unsigned char temp_char,*ch_ptr; + void *ptr; + + if (device_handle==NULL) + return; + + show_pad_info.line=0; + + if (current_type==NULL) { + wmove (show_pad,0,0); + ch_ptr=type_data.u.buffer; + for (l=0;l<file_system_info.block_size/16;l++) { + wprintw (show_pad,"%08ld : ",offset); + for (i=0;i<16;i++) { + if (type_data.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + if (ch_ptr [i]>=' ' && ch_ptr [i]<='z') + wprintw (show_pad,"%c",ch_ptr [i]); + else + wprintw (show_pad,"."); + if (type_data.offset_in_block==offset+i) + wattrset (show_pad,A_NORMAL); + } + wprintw (show_pad," "); + for (i=0;i<16;i++) { + if (type_data.offset_in_block==offset+i) + wattrset (show_pad,A_REVERSE); + + wprintw (show_pad,"%02x",ch_ptr [i]); + + if (type_data.offset_in_block==offset+i) { + wattrset (show_pad,A_NORMAL); + show_pad_info.line=l-l % show_pad_info.display_lines; + } + + wprintw (show_pad," "); + } + wprintw (show_pad,"\n"); + offset+=16; + ch_ptr+=16; + } + show_pad_info.max_line=l-1;show_pad_info.max_col=COLS-1; + refresh_show_pad ();show_info (); + } + else { + wmove (show_pad,0,0);l=0; + for (i=0;i<current_type->fields_num;i++) { + wprintw (show_pad,"%-20s = ",current_type->field_names [i]); + ptr=type_data.u.buffer+offset; + switch (current_type->field_lengths [i]) { + case 1: + temp_char=*((unsigned char *) ptr); + wprintw (show_pad,"%3u (0x%02x",temp_char,temp_char); + if (temp_char>=' ' && temp_char<='z') + wprintw (show_pad," , %c)\n",temp_char); + else + wprintw (show_pad,")\n"); + + offset ++;l++; + break; + case 2: + temp_int=*((unsigned short *) ptr); + wprintw (show_pad,"%u (0x%x)\n",temp_int,temp_int); + offset +=2;l++; + break; + case 4: + temp_long=*((unsigned long *) ptr); + wprintw (show_pad,"%lu\n",temp_long); + offset +=4;l++; + break; + } +/* offset+=current_type->field_lengths [i]; */ + } + current_type->length=offset; + show_pad_info.max_line=l-1; + refresh_show_pad ();show_info (); + } +} + +void next (char *command_line) + +{ + long offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (current_type!=NULL) { + sprintf (buffer,"setoffset type +%ld",offset); + dispatch (buffer); + return; + } + + if (type_data.offset_in_block+offset < file_system_info.block_size) { + type_data.offset_in_block+=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void prev (char *command_line) + +{ + long offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + offset*=atol (buffer); + } + + if (current_type!=NULL) { + sprintf (buffer,"setoffset type -%ld",offset); + dispatch (buffer); + return; + } + + if (type_data.offset_in_block-offset >= 0) { + type_data.offset_in_block-=offset; + sprintf (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Offset out of block\n");refresh_command_win (); + } +} + +void pgdn (char *commnad_line) + +{ + show_pad_info.line+=show_pad_info.display_lines; + refresh_show_pad ();refresh_show_win (); +} + +void pgup (char *command_line) + +{ + show_pad_info.line-=show_pad_info.display_lines; + refresh_show_pad ();refresh_show_win (); +} + +void redraw (char *command_line) + +{ + redraw_all (); + dispatch ("show"); +} + +void remember (char *command_line) + +{ + long entry_num; + char *ptr,buffer [80]; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,buffer); + + entry_num=remember_lifo.entries_count++; + if (entry_num>REMEMBER_COUNT-1) { + entry_num=0; + remember_lifo.entries_count--; + } + + remember_lifo.offset [entry_num]=device_offset; + remember_lifo.type [entry_num]=current_type; + strcpy (remember_lifo.name [entry_num],buffer); + + if (current_type!=NULL) + wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",current_type->name,device_offset,buffer); + else + wprintw (command_win,"Offset %ld remembered as %s\n",device_offset,buffer); + + refresh_command_win (); +} + +void recall (char *command_line) + +{ + char *ptr,buffer [80]; + long entry_num; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + ptr=parse_word (command_line,buffer); + + if (*ptr==0) { + wprintw (command_win,"Error - Argument not specified\n");refresh_command_win (); + return; + } + + ptr=parse_word (ptr,buffer); + + + for (entry_num=remember_lifo.entries_count-1;entry_num>=0;entry_num--) { + if (strcmp (remember_lifo.name [entry_num],buffer)==0) + break; + } + + if (entry_num==-1) { + wprintw (command_win,"Error - Can not recall %s\n",buffer);refresh_command_win (); + return; + } + + sprintf (buffer,"setoffset %ld",remember_lifo.offset [entry_num]);dispatch (buffer); + if (remember_lifo.type [entry_num] != NULL) { + sprintf (buffer,"settype %s",remember_lifo.type [entry_num]->name);dispatch (buffer); + } + + else { + sprintf (buffer,"settype none");dispatch (buffer); + } + + wprintw (command_win,"Object %s in Offset %ld recalled\n",current_type->name,device_offset); + refresh_command_win (); +} + +void enable_write (char *command_line) + +{ + FILE *fp; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if (!AllowChanges) { + wprintw (command_win,"Sorry, write access is not allowed\n"); + return; + } + + if (mounted) { + wprintw (command_win,"Error - Filesystem is mounted\n"); + return; + } + + if ( (fp=fopen (device_name,"r+b"))==NULL) { + wprintw (command_win,"Error - Can not open device %s for reading and writing\n",device_name);refresh_command_win (); + return; + } + fclose (device_handle); + device_handle=fp;write_access=1; + wprintw (command_win,"Write access enabled - Be careful\n");refresh_command_win (); +} + +void disable_write (char *command_line) + +{ + FILE *fp; + + if (device_handle==NULL) { + wprintw (command_win,"Error - No device opened\n");refresh_command_win (); + return; + } + + if ( (fp=fopen (device_name,"rb"))==NULL) { + wprintw (command_win,"Error - Can not open device %s\n",device_name);refresh_command_win (); + return; + } + + fclose (device_handle); + device_handle=fp;write_access=0; + wprintw (command_win,"Write access disabled\n");refresh_command_win (); +} + +void write_data (char *command_line) + +{ + write_type_data (); +} diff --git a/ext2ed/group_com.c b/ext2ed/group_com.c new file mode 100644 index 00000000..ee6aabc1 --- /dev/null +++ b/ext2ed/group_com.c @@ -0,0 +1,182 @@ +/* + +/usr/src/ext2ed/group_com.c + +A part of the extended file system 2 disk editor. + +General user commands + +First written on: April 17 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + +void type_ext2_group_desc___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_group_desc___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",group_info.group_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_group_desc___entry (char *command_line) + +{ + long group_num; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + group_num=atol (buffer); + + if (group_num < 0 || group_num >= file_system_info.groups_count) { + wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return; + } + + device_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); + group_info.group_num=group_num; +} + + +void type_ext2_group_desc___gocopy (char *command_line) + +{ + unsigned long copy_num,offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + copy_num=atol (buffer); + + offset=file_system_info.first_group_desc_offset+copy_num*file_system_info.super_block.s_blocks_per_group*file_system_info.block_size; + + if (offset > file_system_info.file_system_size) { + wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return; + } + + group_info.copy_num=copy_num; + device_offset=offset+group_info.group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); +} + + +void type_ext2_group_desc___show (char *command_line) + +{ + long group_num,temp; + + temp=(device_offset-file_system_info.first_group_desc_offset) % (file_system_info.super_block.s_blocks_per_group*file_system_info.block_size); + group_num=temp/sizeof (struct ext2_group_desc); + + show (command_line); + + wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0); + wprintw (show_win,"Group %ld of %ld ",group_num,file_system_info.groups_count-1); + wprintw (show_win,"in copy %ld ",group_info.copy_num); + if (group_info.copy_num==0) wprintw (show_win,"(Main copy)"); + wprintw (show_win,"\n");refresh_show_win (); + + if (group_num==0) { + wprintw (command_win,"Reached first group descriptor\n"); + wrefresh (command_win); + } + + if (group_num==file_system_info.groups_count-1) { + wprintw (command_win,"Reached last group descriptor\n"); + wrefresh (command_win); + } +} + +void type_ext2_group_desc___inode (char *command_line) + +{ + long inode_offset; + char buffer [80]; + + inode_offset=type_data.u.t_ext2_group_desc.bg_inode_table; + sprintf (buffer,"setoffset block %ld",inode_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_inode");dispatch (buffer); +} + +void type_ext2_group_desc___blockbitmap (char *command_line) + +{ + long block_bitmap_offset; + char buffer [80]; + + block_bitmap_info.entry_num=0; + block_bitmap_info.group_num=group_info.group_num; + + block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap; + sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype block_bitmap");dispatch (buffer); +} + +void type_ext2_group_desc___inodebitmap (char *command_line) + +{ + long inode_bitmap_offset; + char buffer [80]; + + inode_bitmap_info.entry_num=0; + inode_bitmap_info.group_num=group_info.group_num; + + inode_bitmap_offset=type_data.u.t_ext2_group_desc.bg_inode_bitmap; + sprintf (buffer,"setoffset block %ld",inode_bitmap_offset);dispatch (buffer); + sprintf (buffer,"settype inode_bitmap");dispatch (buffer); +} + +void type_ext2_group_desc___setactivecopy (char *command_line) + +{ + struct ext2_group_desc gd; + + gd=type_data.u.t_ext2_group_desc; + dispatch ("gocopy 0"); + type_data.u.t_ext2_group_desc=gd; + dispatch ("show"); +} diff --git a/ext2ed/init.c b/ext2ed/init.c new file mode 100644 index 00000000..ef59b27a --- /dev/null +++ b/ext2ed/init.c @@ -0,0 +1,607 @@ +/* + +/usr/src/ext2ed/init.c + +A part of the extended file system 2 disk editor. + +-------------------------------- +Various initialization routines. +-------------------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <readline.h> +#include <signal.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#include "ext2ed.h" + +char lines_s [80],cols_s [80]; + +void signal_handler (void); + +void prepare_to_close (void) + +{ + close_windows (); + if (device_handle!=NULL) + fclose (device_handle); + free_user_commands (&general_commands); + free_user_commands (&ext2_commands); + free_struct_descriptors (); +} + +int init (void) + +{ + printf ("Initializing ...\n"); + + if (!process_configuration_file ()) { + fprintf (stderr,"Error - Unable to complete configuration. Quitting.\n"); + return (0); + }; + + general_commands.last_command=-1; /* No commands whatsoever meanwhile */ + ext2_commands.last_command=-1; + add_general_commands (); /* Add the general commands, aviable always */ + device_handle=NULL; /* Notice that our device is still not set up */ + device_offset=-1; + current_type=NULL; /* No filesystem specific types yet */ + + remember_lifo.entries_count=0; /* Object memory is empty */ + + init_windows (); /* Initialize the NCURSES interface */ + init_readline (); /* Initialize the READLINE interface */ + init_signals (); /* Initialize the signal handlers */ + write_access=0; /* Write access disabled */ + + strcpy (last_command_line,"help"); /* Show the help screen to the user */ + dispatch ("help"); + return (1); /* Success */ +} + +void add_general_commands (void) + +{ + add_user_command (&general_commands,"help","EXT2ED help system",help); + add_user_command (&general_commands,"set","Changes a variable in the current object",set); + add_user_command (&general_commands,"setdevice","Selects the filesystem block device (e.g. /dev/hda1)",set_device); + add_user_command (&general_commands,"setoffset","Moves asynchronicly in the filesystem",set_offset); + add_user_command (&general_commands,"settype","Tells EXT2ED how to interpert the current object",set_type); + add_user_command (&general_commands,"show","Displays the current object",show); + add_user_command (&general_commands,"pgup","Scrolls data one page up",pgup); + add_user_command (&general_commands,"pgdn","Scrolls data one page down",pgdn); + add_user_command (&general_commands,"redraw","Redisplay the screen",redraw); + add_user_command (&general_commands,"remember","Saves the current position and data information",remember); + add_user_command (&general_commands,"recall","Gets back to the saved object position",recall); + add_user_command (&general_commands,"enablewrite","Enters Read/Write mode - Allows changing the filesystem",enable_write); + add_user_command (&general_commands,"disablewrite","Enters read only mode",disable_write); + add_user_command (&general_commands,"writedata","Write data back to disk",write_data); + add_user_command (&general_commands,"next","Moves to the next byte in hex mode",next); + add_user_command (&general_commands,"prev","Moves to the previous byte in hex mode",prev); +} + +void add_ext2_general_commands (void) + +{ + add_user_command (&ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super); + add_user_command (&ext2_commands,"group","Moves to the first group descriptor",type_ext2___group); + add_user_command (&ext2_commands,"cd","Moves to the directory specified",type_ext2___cd); +} + +int set_struct_descriptors (char *file_name) + +{ + FILE *fp; + char current_line [500],current_word [50],*ch; + char variable_name [50],variable_type [20]; + struct struct_descriptor *current_descriptor; + + if ( (fp=fopen (file_name,"rt"))==NULL) { + wprintw (command_win,"Error - Failed to open descriptors file %s\n",file_name); + refresh_command_win (); return (0); + }; + + while (!feof (fp)) { + fgets (current_line,500,fp); + if (feof (fp)) break; + ch=parse_word (current_line,current_word); + if (strcmp (current_word,"struct")==0) { + ch=parse_word (ch,current_word); + current_descriptor=add_new_descriptor (current_word); + + while (strchr (current_line,'{')==NULL) { + fgets (current_line,500,fp); + if (feof (fp)) break; + }; + if (feof (fp)) break; + + fgets (current_line,500,fp); + + while (strchr (current_line,'}')==NULL) { + while (strchr (current_line,';')==NULL) { + fgets (current_line,500,fp); + if (strchr (current_line,'}')!=NULL) break; + }; + if (strchr (current_line,'}') !=NULL) break; + ch=parse_word (current_line,variable_type); + ch=parse_word (ch,variable_name); + while (variable_name [strlen (variable_name)-1]!=';') { + strcpy (variable_type,variable_name); + ch=parse_word (ch,variable_name); + }; + variable_name [strlen (variable_name)-1]=0; + add_new_variable (current_descriptor,variable_type,variable_name); + fgets (current_line,500,fp); + }; + }; + }; + + fclose (fp); + return (1); +} + +void free_struct_descriptors (void) + +{ + struct struct_descriptor *ptr,*next; + + ptr=first_type; + while (ptr!=NULL) { + next=ptr->next; + free_user_commands (&ptr->type_commands); + free (ptr); + ptr=next; + } + first_type=last_type=current_type=NULL; +} + +void free_user_commands (struct struct_commands *ptr) + +{ + int i; + + for (i=0;i<=ptr->last_command;i++) { + free (ptr->names [i]); + free (ptr->descriptions [i]); + } + + ptr->last_command=-1; +} + +struct struct_descriptor *add_new_descriptor (char *name) + +{ + struct struct_descriptor *ptr; + + if (first_type==NULL) { + first_type=last_type=ptr=(struct struct_descriptor *) malloc (sizeof (struct struct_descriptor)); + if (ptr==NULL) { + printf ("Error - Can not allocate memory - Quitting\n"); + exit (1); + } + ptr->prev=ptr->next=NULL; + strcpy (ptr->name,name); + ptr->length=0; + ptr->fields_num=0; + ptr->type_commands.last_command=-1; + fill_type_commands (ptr); + } + else { + ptr=(struct struct_descriptor *) malloc (sizeof (struct struct_descriptor)); + if (ptr==NULL) { + printf ("Error - Can not allocate memory - Quitting\n"); + exit (1); + } + ptr->prev=last_type;last_type->next=ptr;last_type=ptr; + strcpy (ptr->name,name); + ptr->length=0; + ptr->fields_num=0; + ptr->type_commands.last_command=-1; + fill_type_commands (ptr); + } + return (ptr); +} + +void add_new_variable (struct struct_descriptor *ptr,char *v_type,char *v_name) + +{ + short len=1; + + strcpy (ptr->field_names [ptr->fields_num],v_name); + ptr->field_positions [ptr->fields_num]=ptr->length; + + if (strcasecmp (v_type,"long")==0) len=4; + if (strcasecmp (v_type,"__u32")==0) len=4; + if (strcasecmp (v_type,"__s32")==0) len=4; + + if (strcasecmp (v_type,"__u16")==0) len=2; + if (strcasecmp (v_type,"__s16")==0) len=2; + if (strcasecmp (v_type,"short")==0) len=2; + if (strcasecmp (v_type,"int")==0) len=2; + + if (strcasecmp (v_type,"__u8")==0) len=1; + if (strcasecmp (v_type,"__s8")==0) len=1; + if (strcasecmp (v_type,"char")==0) len=1; + + ptr->field_lengths [ptr->fields_num]=len; + + ptr->length+=len; + ptr->fields_num++; +} + +void fill_type_commands (struct struct_descriptor *ptr) + +/* + +Set specific type user commands. + +*/ + +{ + + if (strcmp ((ptr->name),"file")==0) { + add_user_command (&ptr->type_commands,"show","Shows file data",type_file___show); + add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current file",type_file___inode); + add_user_command (&ptr->type_commands,"display","Specifies data format - text or hex",type_file___display); + add_user_command (&ptr->type_commands,"next","Pass to next byte",type_file___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous byte",type_file___prev); + add_user_command (&ptr->type_commands,"offset","Pass to a specified byte in the current block",type_file___offset); + add_user_command (&ptr->type_commands,"nextblock","Pass to next file block",type_file___nextblock); + add_user_command (&ptr->type_commands,"prevblock","Pass to the previous file block",type_file___prevblock); + add_user_command (&ptr->type_commands,"block","Specify which file block to edit",type_file___block); + add_user_command (&ptr->type_commands,"remember","Saves the file\'s inode position for later reference",type_file___remember); + add_user_command (&ptr->type_commands,"set","Sets the current byte",type_file___set); + add_user_command (&ptr->type_commands,"writedata","Writes the current block to the disk",type_file___writedata); + } + + if (strcmp ((ptr->name),"ext2_inode")==0) { + add_user_command (&ptr->type_commands,"show","Shows inode data",type_ext2_inode___show); + add_user_command (&ptr->type_commands,"next","Move to next inode in current block group",type_ext2_inode___next); + add_user_command (&ptr->type_commands,"prev","Move to next inode in current block group",type_ext2_inode___prev); + add_user_command (&ptr->type_commands,"group","Move to the group descriptors of the current inode table",type_ext2_inode___group); + add_user_command (&ptr->type_commands,"entry","Move to a specified entry in the current inode table",type_ext2_inode___entry); + add_user_command (&ptr->type_commands,"file","Display file data of the current inode",type_ext2_inode___file); + add_user_command (&ptr->type_commands,"dir","Display directory data of the current inode",type_ext2_inode___dir); + } + + if (strcmp ((ptr->name),"dir")==0) { + add_user_command (&ptr->type_commands,"show","Shows current directory data",type_dir___show); + add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current directory",type_dir___inode); + add_user_command (&ptr->type_commands,"next","Pass to the next directory entry",type_dir___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous directory entry",type_dir___prev); + add_user_command (&ptr->type_commands,"followinode","Follows the inode specified in this directory entry",type_dir___followinode); + add_user_command (&ptr->type_commands,"remember","Remember the inode of the current directory entry",type_dir___remember); + add_user_command (&ptr->type_commands,"cd","Changes directory relative to the current directory",type_dir___cd); + add_user_command (&ptr->type_commands,"entry","Moves to a specified entry in the current directory",type_dir___entry); + add_user_command (&ptr->type_commands,"writedata","Writes the current entry to the disk",type_dir___writedata); + add_user_command (&ptr->type_commands,"set","Changes a variable in the current directory entry",type_dir___set); + } + + if (strcmp ((ptr->name),"ext2_super_block")==0) { + add_user_command (&ptr->type_commands,"show","Displays the super block data",type_ext2_super_block___show); + add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the superblock",type_ext2_super_block___gocopy); + add_user_command (&ptr->type_commands,"setactivecopy","Copies the current superblock to the main superblock",type_ext2_super_block___setactivecopy); + } + + if (strcmp ((ptr->name),"ext2_group_desc")==0) { + add_user_command (&ptr->type_commands,"next","Pass to the next block group decriptor",type_ext2_group_desc___next); + add_user_command (&ptr->type_commands,"prev","Pass to the previous group descriptor",type_ext2_group_desc___prev); + add_user_command (&ptr->type_commands,"entry","Pass to a specific group descriptor",type_ext2_group_desc___entry); + add_user_command (&ptr->type_commands,"show","Shows the current group descriptor",type_ext2_group_desc___show); + add_user_command (&ptr->type_commands,"inode","Pass to the inode table of the current group block",type_ext2_group_desc___inode); + add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the group descriptor",type_ext2_group_desc___gocopy); + add_user_command (&ptr->type_commands,"blockbitmap","Show the block allocation bitmap of the current group block",type_ext2_group_desc___blockbitmap); + add_user_command (&ptr->type_commands,"inodebitmap","Show the inode allocation bitmap of the current group block",type_ext2_group_desc___inodebitmap); + add_user_command (&ptr->type_commands,"setactivecopy","Copies the current group descriptor to the main table",type_ext2_super_block___setactivecopy); + } + + if (strcmp ((ptr->name),"block_bitmap")==0) { + add_user_command (&ptr->type_commands,"show","Displays the block allocation bitmap",type_ext2_block_bitmap___show); + add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_block_bitmap___entry); + add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_block_bitmap___next); + add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_block_bitmap___prev); + add_user_command (&ptr->type_commands,"allocate","Allocates the current block",type_ext2_block_bitmap___allocate); + add_user_command (&ptr->type_commands,"deallocate","Deallocates the current block",type_ext2_block_bitmap___deallocate); + } + + if (strcmp ((ptr->name),"inode_bitmap")==0) { + add_user_command (&ptr->type_commands,"show","Displays the inode allocation bitmap",type_ext2_inode_bitmap___show); + add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_inode_bitmap___entry); + add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_inode_bitmap___next); + add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_inode_bitmap___prev); + add_user_command (&ptr->type_commands,"allocate","Allocates the current inode",type_ext2_inode_bitmap___allocate); + add_user_command (&ptr->type_commands,"deallocate","Deallocates the current inode",type_ext2_inode_bitmap___deallocate); + } + +} + +void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback) + +{ + int num; + + num=ptr->last_command; + if (num+1==MAX_COMMANDS_NUM) { + printf ("Internal Error - Can't add command %s\n",name); + return; + } + + ptr->last_command=++num; + + ptr->names [num]=(char *) malloc (strlen (name)+1); + strcpy (ptr->names [num],name); + + if (*description!=0) { + ptr->descriptions [num]=(char *) malloc (strlen (description)+1); + strcpy (ptr->descriptions [num],description); + } + + ptr->callback [num]=callback; +} + +int set_file_system_info (void) + +{ + int ext2_detected=0; + struct ext2_super_block *sb; + + file_system_info.super_block_offset=1024; + file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize; + + low_read ((char *) &file_system_info.super_block,sizeof (struct ext2_super_block),file_system_info.super_block_offset); + + sb=&file_system_info.super_block; + + if (sb->s_magic == EXT2_SUPER_MAGIC) + ext2_detected=1; + + if (ext2_detected) + wprintw (command_win,"Detected extended 2 file system on device %s\n",device_name); + else + wprintw (command_win,"Warning - Extended 2 filesystem not detected on device %s\n",device_name); + + if (!ext2_detected && !ForceExt2) + wprintw (command_win,"You may wish to use the configuration option ForceExt2 on\n"); + + if (ForceExt2 && !ext2_detected) + wprintw (command_win,"Forcing extended 2 filesystem\n"); + + if (ForceDefault || !ext2_detected) + wprintw (command_win,"Forcing default parameters\n"); + + refresh_command_win (); + + if (ext2_detected || ForceExt2) { + add_ext2_general_commands (); + if (!set_struct_descriptors (Ext2Descriptors)) + return (0); + } + + if (!ForceDefault && ext2_detected) { + + file_system_info.block_size=EXT2_MIN_BLOCK_SIZE << sb->s_log_block_size; + if (file_system_info.block_size == EXT2_MIN_BLOCK_SIZE) + file_system_info.first_group_desc_offset=2*EXT2_MIN_BLOCK_SIZE; + else + file_system_info.first_group_desc_offset=file_system_info.block_size; + file_system_info.groups_count=( sb->s_blocks_count-sb->s_first_data_block+sb->s_blocks_per_group-1) / + sb->s_blocks_per_group; + + file_system_info.inodes_per_block=file_system_info.block_size/sizeof (struct ext2_inode); + file_system_info.blocks_per_group=sb->s_inodes_per_group/file_system_info.inodes_per_block; + file_system_info.no_blocks_in_group=sb->s_blocks_per_group; + file_system_info.file_system_size=(sb->s_blocks_count-1)*file_system_info.block_size; + } + + else { + file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize; + file_system_info.block_size=DefaultBlockSize; + file_system_info.no_blocks_in_group=DefaultBlocksInGroup; + } + + if (file_system_info.file_system_size > 2147483647) { + wprintw (command_win,"Sorry, filesystems bigger than 2 GB are currently not supported\n"); + return (0); + } + return (1); +} + +void init_readline (void) + +{ + rl_completion_entry_function=(Function *) complete_command; +} + +void init_signals (void) + +{ + signal (SIGWINCH,(SignalHandler) signal_SIGWINCH_handler); /* Catch SIGWINCH */ + signal (SIGTERM,(SignalHandler) signal_SIGTERM_handler); + signal (SIGSEGV,(SignalHandler) signal_SIGSEGV_handler); + +} + +void signal_SIGWINCH_handler (int sig_num) + +{ + redraw_request=1; /* We will handle it in main.c */ +} + +void signal_SIGTERM_handler (int sig_num) + +{ + prepare_to_close (); + printf ("Terminated due to signal %d\n",sig_num); + exit (1); +} + +void signal_SIGSEGV_handler (int sig_num) + +{ + prepare_to_close (); + printf ("Killed by signal %d !\n",sig_num); + exit (1); +} + +int process_configuration_file (void) + +{ + char buffer [300]; + char option [80],value [80]; + FILE *fp; + + strcpy (buffer,VAR_DIR); + strcat (buffer,"/ext2ed.conf"); + + if ((fp=fopen (buffer,"rt"))==NULL) { + fprintf (stderr,"Error - Unable to open configuration file %s\n",buffer); + return (0); + } + + while (get_next_option (fp,option,value)) { + if (strcasecmp (option,"Ext2Descriptors")==0) { + strcpy (Ext2Descriptors,value); + } + + else if (strcasecmp (option,"AlternateDescriptors")==0) { + strcpy (AlternateDescriptors,value); + } + + else if (strcasecmp (option,"LogFile")==0) { + strcpy (LogFile,value); + } + + else if (strcasecmp (option,"LogChanges")==0) { + if (strcasecmp (value,"on")==0) + LogChanges = 1; + else if (strcasecmp (value,"off")==0) + LogChanges = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"AllowChanges")==0) { + if (strcasecmp (value,"on")==0) + AllowChanges = 1; + else if (strcasecmp (value,"off")==0) + AllowChanges = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"AllowMountedRead")==0) { + if (strcasecmp (value,"on")==0) + AllowMountedRead = 1; + else if (strcasecmp (value,"off")==0) + AllowMountedRead = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"ForceExt2")==0) { + if (strcasecmp (value,"on")==0) + ForceExt2 = 1; + else if (strcasecmp (value,"off")==0) + ForceExt2 = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else if (strcasecmp (option,"DefaultBlockSize")==0) { + DefaultBlockSize = atoi (value); + } + + else if (strcasecmp (option,"DefaultTotalBlocks")==0) { + DefaultTotalBlocks = strtoul (value,NULL,10); + } + + else if (strcasecmp (option,"DefaultBlocksInGroup")==0) { + DefaultBlocksInGroup = strtoul (value,NULL,10); + } + + else if (strcasecmp (option,"ForceDefault")==0) { + if (strcasecmp (value,"on")==0) + ForceDefault = 1; + else if (strcasecmp (value,"off")==0) + ForceDefault = 0; + else { + fprintf (stderr,"Error - Illegal value: %s %s\n",option,value); + fclose (fp);return (0); + } + } + + else { + fprintf (stderr,"Error - Unknown option: %s\n",option); + fclose (fp);return (0); + } + } + + printf ("Configuration completed\n"); + fclose (fp); + return (1); +} + +int get_next_option (FILE *fp,char *option,char *value) + +{ + char *ptr; + char buffer [600]; + + if (feof (fp)) return (0); + do{ + if (feof (fp)) return (0); + fgets (buffer,500,fp); + } while (buffer [0]=='#' || buffer [0]=='\n'); + + ptr=parse_word (buffer,option); + ptr=parse_word (ptr,value); + return (1); +} + +void check_mounted (char *name) + +{ + FILE *fp; + char *ptr; + char current_line [500],current_word [200]; + + mounted=0; + + if ( (fp=fopen ("/etc/mtab","rt"))==NULL) { + wprintw (command_win,"Error - Failed to open /etc/mtab. Assuming filesystem is mounted.\n"); + refresh_command_win ();mounted=1;return; + }; + + while (!feof (fp)) { + fgets (current_line,500,fp); + if (feof (fp)) break; + ptr=parse_word (current_line,current_word); + if (strcasecmp (current_word,name)==0) { + mounted=1;fclose (fp);return; + } + }; + + fclose (fp); + + return; +} \ No newline at end of file diff --git a/ext2ed/inode_com.c b/ext2ed/inode_com.c new file mode 100644 index 00000000..d2c0638f --- /dev/null +++ b/ext2ed/inode_com.c @@ -0,0 +1,436 @@ +/* + +/usr/src/ext2ed/inode_com.c + +A part of the extended file system 2 disk editor. + +Commands relevant to ext2_inode type. + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> + +#include "ext2ed.h" + +void type_ext2_inode___prev (char *command_line) + +{ + + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,first_entry,last_entry; + long inode_num,mult=1; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + mult=atol (buffer); + } + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=0; + + if (entry_num-mult+1>0) { + device_offset-=sizeof (struct ext2_inode)*mult; + entry_num-=mult; + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Entry out of limits\n");refresh_command_win (); + } + + if (entry_num==0) { + wprintw (command_win,"Reached first inode in current group descriptor\n"); + refresh_command_win (); + } +} + +void type_ext2_inode___next (char *command_line) + +{ + + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,first_entry,last_entry; + long inode_num,mult=1; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + mult=atol (buffer); + } + + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=0; + + if (entry_num+mult-1<last_entry) { + device_offset+=sizeof (struct ext2_inode)*mult; + entry_num+=mult; + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); + } + + else { + wprintw (command_win,"Error - Entry out of limits\n");refresh_command_win (); + } + + if (entry_num==last_entry) { + wprintw (command_win,"Reached last inode in current group descriptor\n"); + refresh_command_win (); + } +} + + +void type_ext2_inode___show (char *command_line) + +{ + struct ext2_inode *inode_ptr; + + unsigned short temp; + int i; + + long group_num,group_offset,entry_num,block_num,first_entry,last_entry,inode_num; + struct ext2_group_desc desc; + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=group_num*file_system_info.super_block.s_inodes_per_group+1; + inode_num+=entry_num; + + inode_ptr=&type_data.u.t_ext2_inode; + + show (command_line); + + wmove (show_pad,0,40);wprintw (show_pad,"octal = %06o ",inode_ptr->i_mode); + for (i=6;i>=0;i-=3) { + temp=inode_ptr->i_mode & 0x1ff; + temp=temp >> i; + if (temp & 4) + wprintw (show_pad,"r"); + else + wprintw (show_pad,"-"); + + if (temp & 2) + wprintw (show_pad,"w"); + else + wprintw (show_pad,"-"); + + if (temp & 1) + wprintw (show_pad,"x"); + else + wprintw (show_pad,"-"); + } + wmove (show_pad,3,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_atime)); + wmove (show_pad,4,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_ctime)); + wmove (show_pad,5,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_mtime)); + wmove (show_pad,6,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_dtime)); + + wmove (show_pad,10,40); + temp=inode_ptr->i_flags; + + if (temp & EXT2_SECRM_FL) + wprintw (show_pad,"s"); + else + wprintw (show_pad,"-"); + + + if (temp & EXT2_UNRM_FL) + wprintw (show_pad,"u"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_COMPR_FL) + wprintw (show_pad,"c"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_SYNC_FL) + wprintw (show_pad,"S"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_IMMUTABLE_FL) + wprintw (show_pad,"i"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_APPEND_FL) + wprintw (show_pad,"a"); + else + wprintw (show_pad,"-"); + + if (temp & EXT2_NODUMP_FL) + wprintw (show_pad,"d"); + else + wprintw (show_pad,"-"); + + refresh_show_pad (); + + wmove (show_win,1,0); + + wprintw (show_win,"Inode %ld of %ld. Entry %ld of %ld in group descriptor %ld.\n" + ,inode_num,file_system_info.super_block.s_inodes_count,entry_num,last_entry,group_num); + + wprintw (show_win,"Inode type: "); + + if (inode_num < EXT2_FIRST_INO) { + switch (inode_num) { + case EXT2_BAD_INO: + wprintw (show_win,"Bad blocks inode - "); + break; + case EXT2_ROOT_INO: + wprintw (show_win,"Root inode - "); + break; + case EXT2_ACL_IDX_INO: + wprintw (show_win,"ACL index inode - "); + break; + case EXT2_ACL_DATA_INO: + wprintw (show_win,"ACL data inode - "); + break; + case EXT2_BOOT_LOADER_INO: + wprintw (show_win,"Boot loader inode - "); + break; + case EXT2_UNDEL_DIR_INO: + wprintw (show_win,"Undelete directory inode - "); + break; + default: + wprintw (show_win,"Reserved inode - "); + break; + } + } + if (type_data.u.t_ext2_inode.i_mode==0) + wprintw (show_win,"Free. "); + + if (S_ISREG (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"File. "); + + if (S_ISDIR (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Directory. "); + + if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) { + wprintw (show_win,"Symbolic link. "); + wmove (show_pad,12,40); + + if (inode_ptr->i_size <= 60) + wprintw (show_pad,"-> %s",(char *) &type_data.u.t_ext2_inode.i_block [0]); + else + wprintw (show_pad,"Slow symbolic link\n"); + refresh_show_pad (); + } + + if (S_ISCHR (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Character device."); + + if (S_ISBLK (type_data.u.t_ext2_inode.i_mode)) + wprintw (show_win,"Block device. "); + + wprintw (show_win,"\n");refresh_show_win (); + + if (entry_num==last_entry) { + wprintw (command_win,"Reached last inode in current group descriptor\n"); + refresh_command_win (); + } + + if (entry_num==first_entry) { + wprintw (command_win,"Reached first inode in current group descriptor\n"); + refresh_command_win (); + } + +} + +void type_ext2_inode___entry (char *command_line) + +{ + char *ptr,buffer [80]; + + long group_num,group_offset,entry_num,block_num,wanted_entry; + struct ext2_group_desc desc; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) return; + ptr=parse_word (ptr,buffer); + wanted_entry=atol (buffer); + + block_num=device_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + + if (wanted_entry > entry_num) { + sprintf (buffer,"next %ld",wanted_entry-entry_num); + dispatch (buffer); + } + + else if (wanted_entry < entry_num) { + sprintf (buffer,"prev %ld",entry_num-wanted_entry); + dispatch (buffer); + } +} + +void type_ext2_inode___group (char *command_line) + +{ + char buffer [80]; + + long group_num,group_offset; + + group_num=inode_offset_to_group_num (device_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + sprintf (buffer,"setoffset %ld",group_offset);dispatch (buffer); + sprintf (buffer,"settype ext2_group_desc");dispatch (buffer); +} + +void type_ext2_inode___file (char *command_line) + +{ + char buffer [80]; + + if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not file\n");refresh_command_win (); + return; + } + + if (!init_file_info ()) { + wprintw (command_win,"Error - Unable to show file\n");refresh_command_win (); + return; + } + + sprintf (buffer,"settype file");dispatch (buffer); +} + +void type_ext2_inode___dir (char *command_line) + +{ + char buffer [80]; + + if (!S_ISDIR (type_data.u.t_ext2_inode.i_mode)) { + wprintw (command_win,"Error - Inode type is not directory\n");refresh_command_win (); + return; + } + +/* It is very important to init first_file_info first, as search_dir_entries relies on it */ + + if (!init_dir_info (&first_file_info)) { + wprintw (command_win,"Error - Unable to show directory\n");refresh_command_win (); + return; + } + + file_info=first_file_info; + + sprintf (buffer,"settype dir");dispatch (buffer); +} + +long inode_offset_to_group_num (long inode_offset) + +{ + int found=0; + struct ext2_group_desc desc; + + long block_num,group_offset,group_num; + + block_num=inode_offset/file_system_info.block_size; + + group_offset=file_system_info.first_group_desc_offset; + group_num=(group_offset-file_system_info.first_group_desc_offset)/sizeof (struct ext2_group_desc); + + while (!found && group_num>=0 && group_num<file_system_info.groups_count) { + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + if (block_num>=desc.bg_inode_table && block_num<desc.bg_inode_table+file_system_info.blocks_per_group) + found=1; + else + group_offset+=sizeof (struct ext2_group_desc); + group_num=(group_offset-file_system_info.first_group_desc_offset)/sizeof (struct ext2_group_desc); + } + + if (!found) + return (-1); + + return (group_num); +} + + + +long int inode_offset_to_inode_num (long inode_offset) + +{ + long group_num,group_offset,entry_num,block_num,first_entry,last_entry,inode_num; + struct ext2_group_desc desc; + + block_num=inode_offset/file_system_info.block_size; + + group_num=inode_offset_to_group_num (inode_offset); + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + entry_num=(inode_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode); + first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1; + inode_num=group_num*file_system_info.super_block.s_inodes_per_group+1; + inode_num+=entry_num; + + return (inode_num); +} + +long int inode_num_to_inode_offset (long inode_num) + +{ + long group_num,group_offset,inode_offset,inode_entry; + struct ext2_group_desc desc; + + inode_num--; + + group_num=inode_num/file_system_info.super_block.s_inodes_per_group; + inode_entry=inode_num%file_system_info.super_block.s_inodes_per_group; + group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc); + low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset); + + inode_offset=desc.bg_inode_table*file_system_info.block_size+inode_entry*sizeof (struct ext2_inode); + + return (inode_offset); +} diff --git a/ext2ed/inodebitmap_com.c b/ext2ed/inodebitmap_com.c new file mode 100644 index 00000000..f1fddd45 --- /dev/null +++ b/ext2ed/inodebitmap_com.c @@ -0,0 +1,214 @@ +/* + +/usr/src/ext2ed/inodebitmap_com.c + +A part of the extended file system 2 disk editor. + +------------------------- +Handles the inode bitmap. +------------------------- + +Please refer to the documentation in blockbitmap_com.c - Those two files are almost equal. + +First written on: July 25 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + + +void type_ext2_inode_bitmap___entry (char *command_line) + +{ + unsigned long entry_num; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + entry_num=atol (buffer); + + if (entry_num >= file_system_info.super_block.s_inodes_per_group) { + wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return; + } + + inode_bitmap_info.entry_num=entry_num; + strcpy (buffer,"show");dispatch (buffer); +} + +void type_ext2_inode_bitmap___next (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num+entry_offset); + dispatch (buffer); +} + +void type_ext2_inode_bitmap___prev (char *command_line) + +{ + long entry_offset=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + entry_offset=atol (buffer); + } + + sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num-entry_offset); + dispatch (buffer); +} + +void type_ext2_inode_bitmap___allocate (char *command_line) + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=inode_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_inodes_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much inodes in the group\n"); + refresh_command_win ();return; + } + + while (num) { + allocate_inode (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + +void type_ext2_inode_bitmap___deallocate (char *command_line) + +{ + long entry_num,num=1; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr!=0) { + ptr=parse_word (ptr,buffer); + num=atol (buffer); + } + + entry_num=inode_bitmap_info.entry_num; + if (num > file_system_info.super_block.s_inodes_per_group-entry_num) { + wprintw (command_win,"Error - There aren't that much inodes in the group\n"); + refresh_command_win ();return; + } + + while (num) { + deallocate_inode (entry_num); + num--;entry_num++; + } + + dispatch ("show"); +} + + +void allocate_inode (long entry_num) + +{ + unsigned char bit_mask=1; + int byte_offset,j; + + byte_offset=entry_num/8; + for (j=0;j<entry_num%8;j++) + bit_mask*=2; + type_data.u.buffer [byte_offset] |= bit_mask; +} + +void deallocate_inode (long entry_num) + +{ + unsigned char bit_mask=1; + int byte_offset,j; + + byte_offset=entry_num/8; + for (j=0;j<entry_num%8;j++) + bit_mask*=2; + bit_mask^=0xff; + + type_data.u.buffer [byte_offset] &= bit_mask; +} + +void type_ext2_inode_bitmap___show (char *command_line) + +{ + int i,j; + unsigned char *ptr; + unsigned long inode_num,entry_num; + + ptr=type_data.u.buffer; + show_pad_info.line=0;show_pad_info.max_line=-1; + + wmove (show_pad,0,0); + for (i=0,entry_num=0;i<file_system_info.super_block.s_inodes_per_group/8;i++,ptr++) { + for (j=1;j<=128;j*=2) { + if (entry_num==inode_bitmap_info.entry_num) { + wattrset (show_pad,A_REVERSE); + show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2; + } + + if ((*ptr) & j) + wprintw (show_pad,"1"); + else + wprintw (show_pad,"0"); + + if (entry_num==inode_bitmap_info.entry_num) + wattrset (show_pad,A_NORMAL); + + entry_num++; + } + wprintw (show_pad," "); + if (i%8==7) { + wprintw (show_pad,"\n"); + show_pad_info.max_line++; + } + } + + if (i%8!=7) { + wprintw (show_pad,"\n"); + show_pad_info.max_line++; + } + + refresh_show_pad (); + show_info (); + wmove (show_win,1,0);wprintw (show_win,"Inode bitmap of block group %ld\n",inode_bitmap_info.group_num); + + inode_num=1+inode_bitmap_info.entry_num+inode_bitmap_info.group_num*file_system_info.super_block.s_inodes_per_group; + wprintw (show_win,"Status of inode %ld - ",inode_num); + ptr=type_data.u.buffer+inode_bitmap_info.entry_num/8; + j=1; + for (i=inode_bitmap_info.entry_num % 8;i>0;i--) + j*=2; + if ((*ptr) & j) + wprintw (show_win,"Allocated\n"); + else + wprintw (show_win,"Free\n"); + refresh_show_win (); +} diff --git a/ext2ed/main.c b/ext2ed/main.c new file mode 100644 index 00000000..43130c99 --- /dev/null +++ b/ext2ed/main.c @@ -0,0 +1,374 @@ +/* + +/usr/src/ext2ed/main.c + +A part of the extended file system 2 disk editor. + +------------ +Main program +------------ + +This file mostly contains: + +1. A list of global variables used through the entire program. +2. The parser, which asks the command line from the user. +3. The dispatcher, which analyzes the command line and calls the appropriate handler function. +4. A command pattern matcher which is used along with the readline completion feature. +5. A function which tells the user that an internal error has occured. + +First written on: March 30 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <readline.h> +#include <history.h> + +#include "ext2ed.h" + +/* Global variables */ + +/* + +Configuration file options + +The following variables will be set by init.c to the values selected in the user configuration file. +They are initialized below to some logical defaults. + +*/ + + +char Ext2Descriptors [200]="ext2.descriptors"; /* The location of the ext2 filesystem object definition */ +char AlternateDescriptors [200]=""; /* We allow the user to define additional structures */ +char LogFile [200]="ext2ed.log"; /* The location of the log file - Each write will be logged there */ +int LogChanges=1; /* 1 enables logging, 0 diables logging */ +int AllowChanges=0; /* When set, the enablewrite command will fail */ +int AllowMountedRead=0; /* Behavior when trying to open a mounted filesystem read-only */ +int ForceExt2=0; /* When set, ext2 autodetection is overridden */ +int DefaultBlockSize=1024; +unsigned long DefaultTotalBlocks=2097151; +unsigned long DefaultBlocksInGroup=8192; /* The default values are used when an ext2 filesystem is not */ +int ForceDefault=0; /* detected, or ForceDefault is set */ + +char last_command_line [80]; /* A simple one command cache, in addition to the readline history */ + +char device_name [80]; /* The location of the filesystem */ +FILE *device_handle=NULL; /* This is passed to the fopen / fread ... commands */ +long device_offset; /* The current position in the filesystem */ + /* Note that we have a 2 GB limitation */ + +int mounted=0; /* This is set when we find that the filesystem is mounted */ + +struct struct_commands general_commands,ext2_commands; /* Used to define the general and ext2 commands */ +struct struct_descriptor *first_type,*last_type,*current_type; /* Used to access the double linked list */ +struct struct_type_data type_data; /* The current data is sometimes stored here */ +struct struct_file_system_info file_system_info; /* Essential information on the filesystem */ +struct struct_file_info file_info,first_file_info; /* Used by file_com.c to access files */ +struct struct_group_info group_info; /* Used by group_com.c */ +struct struct_super_info super_info; /* Used by super_com.c */ +struct struct_remember_lifo remember_lifo; /* A circular memory of objects */ +struct struct_block_bitmap_info block_bitmap_info; /* Used by blockbitmap_com.c */ +struct struct_inode_bitmap_info inode_bitmap_info; /* Used by inodebitmap_com.c */ + +int redraw_request=0; /* Is set by a signal handler to handle terminal */ + /* screen size change. */ +int version_major=0,version_minor=1; +char revision_date [80]="August 22 1995"; +char email_address [80]="tgud@tochnapc2.technion.ac.il"; + +int main (void) + +/* We just call the parser to get commands from the user. We quit when parser returns. */ + +{ + if (!init ()) return (0); /* Perform some initial initialization */ + /* Quit if failed */ + + parser (); /* Get and parse user commands */ + + prepare_to_close (); /* Do some cleanup */ + printf ("Quitting ...\n"); + return (1); /* And quit */ +} + + +void parser (void) + +/* + +This function asks the user for a command and calls the dispatcher function, dispatch, to analyze it. +We use the readline library function readline to read the command, hence all the usual readline keys +are available. +The new command is saved both in the readline's history and in our tiny one-command cache, so that +only the enter key is needed to retype it. + +*/ + +{ + char *ptr,command_line [80]; + int quit=0; + + while (!quit) { + + if (redraw_request) { /* Terminal screen size has changed */ + dispatch ("redraw");dispatch ("show");redraw_request=0; + } + + wmove (command_win,0,0);wclrtoeol (command_win);refresh_command_win (); + + mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); /* At last ! I spent ** days ** on this one */ + + /* The ncurses library optimizes cursor movement by */ + /* keeping track of the cursor position. However, by */ + /* using the readline library I'm breaking its */ + /* assumptions. The double -1 arguments tell ncurses */ + /* to disable cursor movement optimization this time. */ + echo (); + ptr=readline ("ext2ed > "); /* Read the user's command line. */ + noecho (); + + strcpy (command_line,ptr); /* Readline allocated the buffer - Copy the string */ + free (ptr); /* and free the allocated buffer */ + + if (*command_line != 0) + add_history (command_line); /* Add the non-empty command to the command histroy */ + + if (*command_line==0) /* If only enter was pressed, recall the last command */ + strcpy (command_line,last_command_line); + + /* Emulate readline's actions for ncurses */ + + mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); /* Again, needed for correct integration of the */ + /* ncurses and readline libraries */ + + werase (command_win); + wprintw (command_win,"ext2ed > ");wprintw (command_win,command_line); + wprintw (command_win,"\n");refresh_command_win (); + + strcpy (last_command_line,command_line); /* Save this command in our tiny cache */ + + quit=dispatch (command_line); /* And call dispatch to do the actual job */ + } +} + + +int dispatch (char *command_line) + +/* + +This is a very important function. Its task is to recieve a command name and link it to a C function. +There are three type of commands: + +1. General commands - Always available and accessed through general_commands. +2. Ext2 specific commands - Available when editing an ext2 filesystem, accessed through ext2_commands. +3. Type specific commands - Those are changing according to the current type. The global + variable current_type points to the current object definition (of type struct_descriptor). + In it, the struct_commands entry contains the type specific commands links. + +Overriding is an important feature - Much like in C++ : The same command name can dispatch to different +functions. The overriding priority is 3,2,1; That is - A type specific command will always override a +general command. This is used through the program to allow fine tuned operation. + +When an handling function is found, it is called along with the command line that was passed to us. The handling +function is then free to interpert the arguments in its own style. + +*/ + +{ + int i,found=0; + + char command [80]; + + parse_word (command_line,command); + + if (strcasecmp (command,"quit")==0) return (1); + + /* 1. Search for type specific commands FIRST - Allows overriding of a general command */ + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command && !found;i++) { + if (strcasecmp (command,current_type->type_commands.names [i])==0) { + (*current_type->type_commands.callback [i]) (command_line); + found=1; + } + } + + /* 2. Now search for ext2 filesystem general commands */ + + if (!found) + for (i=0;i<=ext2_commands.last_command && !found;i++) { + if (strcasecmp (command,ext2_commands.names [i])==0) { + (*ext2_commands.callback [i]) (command_line); + found=1; + } + } + + + /* 3. If not found, search the general commands */ + + if (!found) + for (i=0;i<=general_commands.last_command && !found;i++) { + if (strcasecmp (command,general_commands.names [i])==0) { + (*general_commands.callback [i]) (command_line); + found=1; + } + } + + /* 4. If not found, issue an error message and return */ + + if (!found) { + wprintw (command_win,"Error: Unknown command\n"); + refresh_command_win (); + } + + return (0); +} + +char *parse_word (char *source,char *dest) + +/* + +This function copies the next word in source to the variable dest, ignoring whitespaces. +It returns a pointer to the next word in source. +It is used to split the command line into command and arguments. + +*/ + +{ + char ch,*source_ptr,*target_ptr; + + if (*source==0) { + *dest=0; + return (source); + }; + + source_ptr=source;target_ptr=dest; + do { + ch=*source_ptr++; + } while (! (ch>' ' && ch<='z') && ch!=0); + + while (ch>' ' && ch<='z') { + *target_ptr++=ch; + ch=*source_ptr++; + } + + *target_ptr=0; + + source_ptr--; + do { + ch=*source_ptr++; + } while (! (ch>' ' && ch<='z') && ch!=0); + + return (--source_ptr); +} + +char *complete_command (char *text,int state) + +/* + +text is the partial command entered by the user; We assume that it is a part of a command - I didn't write code +for smarter completion. + +The state variable is an index which tells us how many possible completions we already returned to readline. + +We return only one possible completion or (char *) NULL if there are no more completions. This +function will be called by readline over and over until we tell it to stop. + +While scanning for possible completions, we use the same priority definition which was used in dispatch. + +*/ + +{ + int state_index=-1; + int i,len; + + len=strlen (text); + + /* Is the command type specific ? */ + + if (current_type != NULL) + for (i=0;i<=current_type->type_commands.last_command;i++) { + if (strncmp (current_type->type_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) { + return (dupstr (current_type->type_commands.names [i])); + } + } + } + + /* No, pehaps ext2 specific command then ? */ + + for (i=0;i<=ext2_commands.last_command;i++) { + if (strncmp (ext2_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr (ext2_commands.names [i])); + } + } + + + /* Check for a general command */ + + for (i=0;i<=general_commands.last_command;i++) { + if (strncmp (general_commands.names [i],text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr (general_commands.names [i])); + } + } + + /* quit is handled differently */ + + if (strncmp ("quit",text,len)==0) { + state_index++; + if (state==state_index) + return (dupstr ("quit")); + } + + /* No more completions */ + + return ((char *) NULL); +} + +char *dupstr (char *src) + +/* + +Nothing special - Just allocates enough space and copy the string. + +*/ + +{ + char *ptr; + + ptr=(char *) malloc (strlen (src)+1); + strcpy (ptr,src); + return (ptr); +} + +#ifdef DEBUG + +void internal_error (char *description,char *source_name,char *function_name) + +/* + +This function reports an internal error. It is almost not used. One place in which I do check for internal +errors is disk.c. + +We just report the error, and try to continue ... + +*/ + +{ + wprintw (command_win,"Internal error - Found by source: %s.c , function: %s\n",source_name,function_name); + wprintw (command_win,"\t%s\n",description); + wprintw (command_win,"Press enter to (hopefully) continue\n"); + refresh_command_win ();getch ();werase (command_win); +} + +#endif \ No newline at end of file diff --git a/ext2ed/super_com.c b/ext2ed/super_com.c new file mode 100644 index 00000000..0541ff3b --- /dev/null +++ b/ext2ed/super_com.c @@ -0,0 +1,159 @@ +/* + +/usr/src/ext2ed/super_com.c + +A part of the extended file system 2 disk editor. + +---------------------- +Handles the superblock +---------------------- + +First written on: April 9 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> + +#include "ext2ed.h" + +void type_ext2_super_block___show (char *command_line) + +{ + struct ext2_super_block *super; + super=&type_data.u.t_ext2_super_block; + + show (command_line); + + if (super->s_blocks_count != 0) { + wmove (show_pad,2,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_r_blocks_count/ (float) super->s_blocks_count); + wmove (show_pad,3,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_free_blocks_count/ (float) super->s_blocks_count); + } + + if (super->s_inodes_count != 0) { + wmove (show_pad,4,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_free_inodes_count/ (float) super->s_inodes_count); + } + + wmove (show_pad,6,40); + switch (super->s_log_block_size) { + case 0: wprintw (show_pad,"1024 bytes");break; + case 1: wprintw (show_pad,"2048 bytes");break; + case 2: wprintw (show_pad,"4096 bytes");break; + } + wmove (show_pad,11,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_mtime)); + wmove (show_pad,12,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_wtime)); + wmove (show_pad,19,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_lastcheck)); + wmove (show_pad,15,40); + + switch (type_data.u.t_ext2_super_block.s_magic) { + case EXT2_SUPER_MAGIC: + wprintw (show_pad,"ext2 >= 0.2B"); + break; + case EXT2_PRE_02B_MAGIC: + wprintw (show_pad,"ext2 < 0.2B (not supported)"); + break; + default: + wprintw (show_pad,"Unknown"); + break; + } + + wmove (show_pad,16,40); + if (type_data.u.t_ext2_super_block.s_state & 0x1) + wprintw (show_pad,"clean "); + else + wprintw (show_pad,"not clean "); + + if (type_data.u.t_ext2_super_block.s_state & 0x2) + wprintw (show_pad,"with errors "); + else + wprintw (show_pad,"with no errors"); + + wmove (show_pad,17,40); + + switch (type_data.u.t_ext2_super_block.s_errors) { + case EXT2_ERRORS_CONTINUE: + wprintw (show_pad,"Continue"); + break; + case EXT2_ERRORS_RO: + wprintw (show_pad,"Remount read only"); + break; + case EXT2_ERRORS_PANIC: + wprintw (show_pad,"Issue kernel panic"); + break; + default: + wprintw (show_pad,"Unknown"); + break; + } + + wmove (show_pad,21,40); + + switch (type_data.u.t_ext2_super_block.s_creator_os) { + + case EXT2_OS_LINUX: + wprintw (show_pad,"Linux :-)"); + break; + + case EXT2_OS_HURD: + wprintw (show_pad,"Hurd"); + break; + + case EXT2_OS_MASIX: + wprintw (show_pad,"Masix"); + break; + + default: + wprintw (show_pad,"Unknown"); + break; + } + + refresh_show_pad (); + + wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0); + wprintw (show_win,"Superblock copy %ld ",super_info.copy_num); + if (super_info.copy_num==0) + wprintw (show_win,"(main copy)"); + wprintw (show_win,"\n"); + refresh_show_win (); +} + +void type_ext2_super_block___gocopy (char *command_line) + +{ + unsigned long copy_num,offset; + char *ptr,buffer [80]; + + ptr=parse_word (command_line,buffer); + if (*ptr==0) { + wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return; + } + ptr=parse_word (ptr,buffer); + + copy_num=atol (buffer); + + offset=file_system_info.super_block_offset+copy_num*file_system_info.no_blocks_in_group*file_system_info.block_size; + + if (offset > file_system_info.file_system_size) { + wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return; + } + + super_info.copy_num=copy_num; + device_offset=offset; + + sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer); + strcpy (buffer,"show");dispatch (buffer); +} + +void type_ext2_super_block___setactivecopy (char *command_line) + +{ + struct ext2_super_block sb; + + sb=type_data.u.t_ext2_super_block; + dispatch ("gocopy 0"); + type_data.u.t_ext2_super_block=sb; + dispatch ("show"); +} diff --git a/ext2ed/win.c b/ext2ed/win.c new file mode 100644 index 00000000..09ee22dd --- /dev/null +++ b/ext2ed/win.c @@ -0,0 +1,169 @@ +/* + +/usr/src/ext2ed/win.c + +A part of the extended file system 2 disk editor. + +-------------------------------------------------------- +Window management - Interfacing with the ncurses library +-------------------------------------------------------- + +First written on: April 17 1995 + +Copyright (C) 1995 Gadi Oxman + +*/ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "ext2ed.h" + +struct struct_pad_info show_pad_info; +WINDOW *title_win,*show_win,*command_win,*show_pad; + +void init_windows (void) + +{ + char title_string [80]; + + initscr (); + + if (LINES<TITLE_WIN_LINES+SHOW_WIN_LINES+COMMAND_WIN_LINES+3) { + printf ("Sorry, your terminal screen is too small\n"); + printf ("Error - Can not initialize windows\n"); + exit (1); + } + + title_win=newwin (TITLE_WIN_LINES,COLS,0,0); + show_win=newwin (SHOW_WIN_LINES,COLS,TITLE_WIN_LINES,0); + show_pad=newpad (SHOW_PAD_LINES,SHOW_PAD_COLS); + command_win=newwin (COMMAND_WIN_LINES,COLS,LINES-COMMAND_WIN_LINES,0); + + if (title_win==NULL || show_win==NULL || show_pad==NULL || command_win==NULL) { + printf ("Error - Not enough memory - Can not initialize windows\n");exit (1); + } + + box (title_win,0,0); + sprintf (title_string,"EXT2ED - Extended-2 File System editor ver %d.%d (%s)",version_major,version_minor,revision_date); + wmove (title_win,TITLE_WIN_LINES/2,(COLS-strlen (title_string))/2); + wprintw (title_win,title_string); + +#ifdef OLD_NCURSES + wattrset (show_win,A_NORMAL);werase (show_win); +#else + wbkgdset (show_win,A_REVERSE);werase (show_win); +#endif + show_pad_info.line=0;show_pad_info.col=0; + show_pad_info.display_lines=LINES-TITLE_WIN_LINES-SHOW_WIN_LINES-COMMAND_WIN_LINES-2; + show_pad_info.display_cols=COLS; + show_pad_info.max_line=show_pad_info.display_lines-1;show_pad_info.max_col=show_pad_info.display_cols-1; + show_pad_info.disable_output=0; + + scrollok (command_win,TRUE); + + refresh_title_win ();refresh_show_win ();refresh_show_pad ();refresh_command_win (); +} + +void refresh_title_win (void) + +{ + wrefresh (title_win); +} + +void refresh_show_win (void) + +{ + int current_page,total_pages; + + current_page=show_pad_info.line/show_pad_info.display_lines+1; + if (show_pad_info.line%show_pad_info.display_lines) + current_page++; + total_pages=show_pad_info.max_line/show_pad_info.display_lines+1; + + wmove (show_win,2,COLS-18); + wprintw (show_win,"Page %d of %d\n",current_page,total_pages); + + wmove (show_win,2,COLS-18); + wrefresh (show_win); +} + + +void refresh_show_pad (void) + +{ + int left,top,right,bottom,i; + + if (show_pad_info.disable_output) + return; + + if (show_pad_info.max_line < show_pad_info.display_lines-1) { + for (i=show_pad_info.max_line+1;i<show_pad_info.display_lines;i++) { + wmove (show_pad,i,0);wprintw (show_pad,"\n"); + } + } + left=0;right=show_pad_info.display_cols-1; + top=TITLE_WIN_LINES+SHOW_WIN_LINES+1;bottom=top+show_pad_info.display_lines-1; + + if (show_pad_info.line > show_pad_info.max_line-show_pad_info.display_lines+1) + show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines+1; + + if (show_pad_info.line < 0) + show_pad_info.line=0; + +#ifdef OLD_NCURSES + prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,show_pad_info.display_lines-1,show_pad_info.display_cols-1); +#else + prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,top+show_pad_info.display_lines-1,left+show_pad_info.display_cols-1); +#endif +} + +void refresh_command_win (void) + +{ + wrefresh (command_win); +} + +void close_windows (void) + +{ + echo (); + + delwin (title_win); + delwin (command_win); + delwin (show_win); + delwin (show_pad); + + endwin (); +} + +void show_info (void) + +{ + int block_num,block_offset; + + block_num=device_offset/file_system_info.block_size; + block_offset=device_offset%file_system_info.block_size; + + wmove (show_win,0,0); + wprintw (show_win,"Offset %-3ld in block %ld. ",block_offset,block_num); + if (current_type != NULL) + wprintw (show_win,"Type: %s\n",current_type->name); + else + wprintw (show_win,"Type: %s\n","none"); + + refresh_show_win (); +} + + +void redraw_all (void) + +{ + close_windows (); + init_windows (); + + wmove (command_win,0,0); + mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); + +} \ No newline at end of file