mirror of https://github.com/vitalif/e2fsprogs
152 lines
3.4 KiB
C
152 lines
3.4 KiB
C
/*
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* link.c --- create or delete links in a ext2fs directory
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*
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* Copyright (C) 1993 Theodore Ts'o. This file may be redistributed
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* under the terms of the GNU Public License.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <linux/ext2_fs.h>
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#include "ext2fs.h"
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struct link_struct {
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const char *name;
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int namelen;
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ino_t inode;
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int flags;
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int done;
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};
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static int link_proc(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *private)
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{
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struct link_struct *ls = (struct link_struct *) private;
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struct ext2_dir_entry *next;
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int rec_len;
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int ret = 0;
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rec_len = EXT2_DIR_REC_LEN(ls->namelen);
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/*
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* See if the following directory entry (if any) is unused;
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* if so, absorb it into this one.
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*/
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next = (struct ext2_dir_entry *) (buf + offset + dirent->rec_len);
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if ((offset + dirent->rec_len < blocksize - 8) &&
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(next->inode == 0) &&
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(offset + dirent->rec_len + next->rec_len <= blocksize)) {
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dirent->rec_len += next->rec_len;
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ret = DIRENT_CHANGED;
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}
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/*
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* If the directory entry is used, see if we can split the
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* directory entry to make room for the new name. If so,
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* truncate it and return.
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*/
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if (dirent->inode) {
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if (dirent->rec_len < (EXT2_DIR_REC_LEN(dirent->name_len) +
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rec_len))
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return ret;
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rec_len = dirent->rec_len - EXT2_DIR_REC_LEN(dirent->name_len);
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dirent->rec_len = EXT2_DIR_REC_LEN(dirent->name_len);
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next = (struct ext2_dir_entry *) (buf + offset +
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dirent->rec_len);
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next->inode = 0;
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next->name_len = 0;
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next->rec_len = rec_len;
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return DIRENT_CHANGED;
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}
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/*
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* If we get this far, then the directory entry is not used.
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* See if we can fit the request entry in. If so, do it.
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*/
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if (dirent->rec_len < rec_len)
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return ret;
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dirent->inode = ls->inode;
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dirent->name_len = ls->namelen;
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strncpy(dirent->name, ls->name, ls->namelen);
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ls->done++;
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return DIRENT_ABORT|DIRENT_CHANGED;
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}
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errcode_t ext2fs_link(ext2_filsys fs, ino_t dir, const char *name, ino_t ino,
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int flags)
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{
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errcode_t retval;
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struct link_struct ls;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!(fs->flags & EXT2_FLAG_RW))
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return EXT2_ET_RO_FILSYS;
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ls.name = name;
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ls.namelen = name ? strlen(name) : 0;
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ls.inode = ino;
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ls.flags = 0;
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ls.done = 0;
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retval = ext2fs_dir_iterate(fs, dir, DIRENT_FLAG_INCLUDE_EMPTY,
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0, link_proc, &ls);
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if (retval)
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return retval;
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return (ls.done) ? 0 : EXT2_ET_DIR_NO_SPACE;
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}
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static int unlink_proc(struct ext2_dir_entry *dirent,
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int offset,
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int blocksize,
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char *buf,
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void *private)
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{
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struct link_struct *ls = (struct link_struct *) private;
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if (ls->name && (dirent->name_len != ls->namelen))
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return 0;
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if (ls->name && strncmp(ls->name, dirent->name, dirent->name_len))
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return 0;
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if (ls->inode && (dirent->inode != ls->inode))
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return 0;
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dirent->inode = 0;
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ls->done++;
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return DIRENT_ABORT|DIRENT_CHANGED;
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}
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errcode_t ext2fs_unlink(ext2_filsys fs, ino_t dir, const char *name, ino_t ino,
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int flags)
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{
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errcode_t retval;
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struct link_struct ls;
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EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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if (!(fs->flags & EXT2_FLAG_RW))
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return EXT2_ET_RO_FILSYS;
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ls.name = name;
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ls.namelen = name ? strlen(name) : 0;
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ls.inode = ino;
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ls.flags = 0;
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ls.done = 0;
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retval = ext2fs_dir_iterate(fs, dir, 0, 0, unlink_proc, &ls);
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if (retval)
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return retval;
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return (ls.done) ? 0 : EXT2_ET_DIR_NO_SPACE;
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}
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