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e2fsprogs/lib/ext2fs/inode.c

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/*
* inode.c --- utility routines to read and write inodes
*
* Copyright (C) 1993, 1994, 1995, 1996, 1997 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <linux/ext2_fs.h>
#include "ext2fsP.h"
struct ext2_struct_inode_scan {
int magic;
ext2_filsys fs;
ino_t current_inode;
blk_t current_block;
dgrp_t current_group;
int inodes_left, blocks_left, groups_left;
int inode_buffer_blocks;
char * inode_buffer;
int inode_size;
char * ptr;
int bytes_left;
char *temp_buffer;
errcode_t (*done_group)(ext2_filsys fs,
ext2_inode_scan scan,
dgrp_t group,
void * private);
void * done_group_data;
int bad_block_ptr;
int scan_flags;
int reserved[6];
};
errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
ext2_inode_scan *ret_scan)
{
ext2_inode_scan scan;
errcode_t retval;
errcode_t (*save_get_blocks)(ext2_filsys fs, ino_t ino, blk_t *blocks);
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
/*
* If fs->badblocks isn't set, then set it --- since the inode
* scanning functions require it.
*/
if (fs->badblocks == 0) {
/*
* Temporarly save fs->get_blocks and set it to zero,
* for compatibility with old e2fsck's.
*/
save_get_blocks = fs->get_blocks;
fs->get_blocks = 0;
retval = ext2fs_read_bb_inode(fs, &fs->badblocks);
if (retval && fs->badblocks) {
badblocks_list_free(fs->badblocks);
fs->badblocks = 0;
}
fs->get_blocks = save_get_blocks;
}
scan = (ext2_inode_scan) malloc(sizeof(struct ext2_struct_inode_scan));
if (!scan)
return ENOMEM;
memset(scan, 0, sizeof(struct ext2_struct_inode_scan));
scan->magic = EXT2_ET_MAGIC_INODE_SCAN;
scan->fs = fs;
scan->inode_size = EXT2_INODE_SIZE(fs->super);
scan->bytes_left = 0;
scan->current_group = -1;
scan->inode_buffer_blocks = buffer_blocks ? buffer_blocks : 8;
scan->groups_left = fs->group_desc_count;
scan->inode_buffer = malloc(scan->inode_buffer_blocks * fs->blocksize);
scan->done_group = 0;
scan->done_group_data = 0;
scan->bad_block_ptr = 0;
if (!scan->inode_buffer) {
free(scan);
return ENOMEM;
}
scan->temp_buffer = malloc(scan->inode_size);
if (!scan->temp_buffer) {
free(scan->inode_buffer);
free(scan);
return ENOMEM;
}
if (scan->fs->badblocks && scan->fs->badblocks->num)
scan->scan_flags |= EXT2_SF_CHK_BADBLOCKS;
*ret_scan = scan;
return 0;
}
void ext2fs_close_inode_scan(ext2_inode_scan scan)
{
if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
return;
free(scan->inode_buffer);
scan->inode_buffer = NULL;
free(scan->temp_buffer);
scan->temp_buffer = NULL;
free(scan);
return;
}
void ext2fs_set_inode_callback(ext2_inode_scan scan,
errcode_t (*done_group)(ext2_filsys fs,
ext2_inode_scan scan,
dgrp_t group,
void * private),
void *done_group_data)
{
if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
return;
scan->done_group = done_group;
scan->done_group_data = done_group_data;
}
int ext2fs_inode_scan_flags(ext2_inode_scan scan, int set_flags,
int clear_flags)
{
int old_flags;
if (!scan || (scan->magic != EXT2_ET_MAGIC_INODE_SCAN))
return 0;
old_flags = scan->scan_flags;
scan->scan_flags &= ~clear_flags;
scan->scan_flags |= set_flags;
return old_flags;
}
/*
* This function is called by ext2fs_get_next_inode when it needs to
* get ready to read in a new blockgroup.
*/
static errcode_t get_next_blockgroup(ext2_inode_scan scan)
{
scan->current_group++;
scan->groups_left--;
scan->current_block = scan->fs->
group_desc[scan->current_group].bg_inode_table;
scan->bytes_left = 0;
scan->inodes_left = EXT2_INODES_PER_GROUP(scan->fs->super);
scan->blocks_left = scan->fs->inode_blocks_per_group;
return 0;
}
errcode_t ext2fs_inode_scan_goto_blockgroup(ext2_inode_scan scan,
int group)
{
scan->current_group = group - 1;
scan->groups_left = scan->fs->group_desc_count - group;
return get_next_blockgroup(scan);
}
/*
* This function is called by get_next_blocks() to check for bad
* blocks in the inode table.
*
* This function assumes that badblocks_list->list is sorted in
* increasing order.
*/
static errcode_t check_for_inode_bad_blocks(ext2_inode_scan scan,
int *num_blocks)
{
blk_t blk = scan->current_block;
badblocks_list bb = scan->fs->badblocks;
/*
* If the inode table is missing, then obviously there are no
* bad blocks. :-)
*/
if (blk == 0)
return 0;
/*
* If the current block is greater than the bad block listed
* in the bad block list, then advance the pointer until this
* is no longer the case. If we run out of bad blocks, then
* we don't need to do any more checking!
*/
while (blk > bb->list[scan->bad_block_ptr]) {
if (++scan->bad_block_ptr >= bb->num) {
scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
return 0;
}
}
/*
* If the current block is equal to the bad block listed in
* the bad block list, then handle that one block specially.
* (We could try to handle runs of bad blocks, but that
* only increases CPU efficiency by a small amount, at the
* expense of a huge expense of code complexity, and for an
* uncommon case at that.)
*/
if (blk == bb->list[scan->bad_block_ptr]) {
scan->scan_flags |= EXT2_SF_BAD_INODE_BLK;
*num_blocks = 1;
if (++scan->bad_block_ptr >= bb->num)
scan->scan_flags &= ~EXT2_SF_CHK_BADBLOCKS;
return 0;
}
/*
* If there is a bad block in the range that we're about to
* read in, adjust the number of blocks to read so that we we
* don't read in the bad block. (Then the next block to read
* will be the bad block, which is handled in the above case.)
*/
if ((blk + *num_blocks) > bb->list[scan->bad_block_ptr])
*num_blocks = bb->list[scan->bad_block_ptr] - blk;
return 0;
}
/*
* This function is called by ext2fs_get_next_inode when it needs to
* read in more blocks from the current blockgroup's inode table.
*/
static errcode_t get_next_blocks(ext2_inode_scan scan)
{
int num_blocks;
errcode_t retval;
/*
* Figure out how many blocks to read; we read at most
* inode_buffer_blocks, and perhaps less if there aren't that
* many blocks left to read.
*/
num_blocks = scan->inode_buffer_blocks;
if (num_blocks > scan->blocks_left)
num_blocks = scan->blocks_left;
/*
* If the past block "read" was a bad block, then mark the
* left-over extra bytes as also being bad.
*/
if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK) {
if (scan->bytes_left)
scan->scan_flags |= EXT2_SF_BAD_EXTRA_BYTES;
scan->scan_flags &= ~EXT2_SF_BAD_INODE_BLK;
}
/*
* Do inode bad block processing, if necessary.
*/
if (scan->scan_flags & EXT2_SF_CHK_BADBLOCKS) {
retval = check_for_inode_bad_blocks(scan, &num_blocks);
if (retval)
return retval;
}
if ((scan->scan_flags & EXT2_SF_BAD_INODE_BLK) ||
(scan->current_block == 0)) {
memset(scan->inode_buffer, 0,
num_blocks * scan->fs->blocksize);
} else {
retval = io_channel_read_blk(scan->fs->io,
scan->current_block,
num_blocks, scan->inode_buffer);
if (retval)
return EXT2_ET_NEXT_INODE_READ;
}
scan->ptr = scan->inode_buffer;
scan->bytes_left = num_blocks * scan->fs->blocksize;
scan->blocks_left -= num_blocks;
if (scan->current_block)
scan->current_block += num_blocks;
return 0;
}
errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ino_t *ino,
struct ext2_inode *inode)
{
errcode_t retval;
int extra_bytes = 0;
EXT2_CHECK_MAGIC(scan, EXT2_ET_MAGIC_INODE_SCAN);
/*
* Do we need to start reading a new block group?
*/
if (scan->inodes_left <= 0) {
retry:
if (scan->done_group) {
retval = (scan->done_group)
(scan->fs, scan, scan->current_group,
scan->done_group_data);
if (retval)
return retval;
}
if (scan->groups_left <= 0) {
*ino = 0;
return 0;
}
retval = get_next_blockgroup(scan);
if (retval)
return retval;
if (scan->current_block == 0) {
if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
goto retry;
} else
return EXT2_ET_MISSING_INODE_TABLE;
}
}
/*
* Have we run out of space in the inode buffer? If so, we
* need to read in more blocks.
*/
if (scan->bytes_left < scan->inode_size) {
memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
extra_bytes = scan->bytes_left;
retval = get_next_blocks(scan);
if (retval)
return retval;
}
retval = 0;
if (extra_bytes) {
memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
scan->inode_size - extra_bytes);
scan->ptr += scan->inode_size - extra_bytes;
scan->bytes_left -= scan->inode_size - extra_bytes;
if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
ext2fs_swap_inode(scan->fs, inode,
(struct ext2_inode *) scan->temp_buffer, 0);
else
*inode = *((struct ext2_inode *) scan->temp_buffer);
if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
} else {
if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
ext2fs_swap_inode(scan->fs, inode,
(struct ext2_inode *) scan->ptr, 0);
else
*inode = *((struct ext2_inode *) scan->ptr);
scan->ptr += scan->inode_size;
scan->bytes_left -= scan->inode_size;
if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
}
scan->inodes_left--;
scan->current_inode++;
*ino = scan->current_inode;
return retval;
}
/*
* Functions to read and write a single inode.
*/
static char *inode_buffer = 0;
static blk_t inode_buffer_block = 0;
static int inode_buffer_size = 0;
#define INODE_CACHE_SIZE 4
#ifdef INODE_CACHE_SIZE
static int cache_last = -1;
static struct {
ino_t inode;
struct ext2_inode value;
} inode_cache[INODE_CACHE_SIZE];
#endif
errcode_t ext2fs_read_inode (ext2_filsys fs, ino_t ino,
struct ext2_inode * inode)
{
unsigned long group, block, block_nr, offset;
char *ptr;
errcode_t retval;
int clen, length, i;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
/* Check to see if user has an override function */
if (fs->read_inode) {
retval = (fs->read_inode)(fs, ino, inode);
if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
return retval;
}
/* Check to see if it's in the inode cache */
#ifdef INODE_CACHE_SIZE
if (cache_last == -1) {
for (i=0; i < INODE_CACHE_SIZE; i++)
inode_cache[i].inode = 0;
cache_last = INODE_CACHE_SIZE-1;
} else for (i=0; i < INODE_CACHE_SIZE; i++) {
if (inode_cache[i].inode == ino) {
*inode = inode_cache[i].value;
return 0;
}
}
#endif
if (ino > fs->super->s_inodes_count)
return EXT2_ET_BAD_INODE_NUM;
if (inode_buffer_size != fs->blocksize) {
if (inode_buffer)
free(inode_buffer);
inode_buffer_size = 0;
inode_buffer = malloc(fs->blocksize);
if (!inode_buffer)
return ENOMEM;
inode_buffer_size = fs->blocksize;
inode_buffer_block = 0;
}
group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
EXT2_INODE_SIZE(fs->super);
block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
if (!fs->group_desc[group].bg_inode_table)
return EXT2_ET_MISSING_INODE_TABLE;
block_nr = fs->group_desc[group].bg_inode_table + block;
if (block_nr != inode_buffer_block) {
retval = io_channel_read_blk(fs->io, block_nr, 1,
inode_buffer);
if (retval)
return retval;
inode_buffer_block = block_nr;
}
offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
ptr = ((char *) inode_buffer) + offset;
memset(inode, 0, sizeof(struct ext2_inode));
length = EXT2_INODE_SIZE(fs->super);
if (length > sizeof(struct ext2_inode))
length = sizeof(struct ext2_inode);
if ((offset + length) > EXT2_BLOCK_SIZE(fs->super)) {
clen = EXT2_BLOCK_SIZE(fs->super) - offset;
memcpy((char *) inode, ptr, clen);
length -= clen;
retval = io_channel_read_blk(fs->io, block_nr+1, 1,
inode_buffer);
if (retval)
return retval;
inode_buffer_block = block_nr+1;
memcpy(((char *) inode) + clen,
inode_buffer, length);
} else
memcpy((char *) inode, ptr, length);
if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
ext2fs_swap_inode(fs, inode, inode, 0);
/* Update the inode cache */
#ifdef INODE_CACHE_SIZE
cache_last = (cache_last + 1) % INODE_CACHE_SIZE;
inode_cache[cache_last].inode = ino;
inode_cache[cache_last].value = *inode;
#endif
return 0;
}
errcode_t ext2fs_write_inode(ext2_filsys fs, ino_t ino,
struct ext2_inode * inode)
{
unsigned long group, block, block_nr, offset;
errcode_t retval;
struct ext2_inode temp_inode;
char *ptr;
int clen, length, i;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
/* Check to see if user provided an override function */
if (fs->write_inode) {
retval = (fs->write_inode)(fs, ino, inode);
if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
return retval;
}
/* Check to see if the inode cache needs to be updated */
#ifdef INODE_CACHE_SIZE
for (i=0; i < INODE_CACHE_SIZE; i++) {
if (inode_cache[i].inode == ino) {
inode_cache[i].value = *inode;
break;
}
}
#endif
if (!(fs->flags & EXT2_FLAG_RW))
return EXT2_ET_RO_FILSYS;
if (ino > fs->super->s_inodes_count)
return EXT2_ET_BAD_INODE_NUM;
if (inode_buffer_size != fs->blocksize) {
if (inode_buffer)
free(inode_buffer);
inode_buffer_size = 0;
inode_buffer = malloc(fs->blocksize);
if (!inode_buffer)
return ENOMEM;
inode_buffer_size = fs->blocksize;
inode_buffer_block = 0;
}
if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
ext2fs_swap_inode(fs, &temp_inode, inode, 1);
else
memcpy(&temp_inode, inode, sizeof(struct ext2_inode));
group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
EXT2_INODE_SIZE(fs->super);
block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
if (!fs->group_desc[group].bg_inode_table)
return EXT2_ET_MISSING_INODE_TABLE;
block_nr = fs->group_desc[group].bg_inode_table + block;
offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);
ptr = (char *) inode_buffer + offset;
length = EXT2_INODE_SIZE(fs->super);
clen = length;
if (length > sizeof(struct ext2_inode))
length = sizeof(struct ext2_inode);
if (inode_buffer_block != block_nr) {
retval = io_channel_read_blk(fs->io, block_nr, 1,
inode_buffer);
if (retval)
return retval;
inode_buffer_block = block_nr;
}
if ((offset + length) > EXT2_BLOCK_SIZE(fs->super)) {
clen = EXT2_BLOCK_SIZE(fs->super) - offset;
length -= clen;
} else {
length = 0;
}
memcpy(ptr, &temp_inode, clen);
retval = io_channel_write_blk(fs->io, block_nr, 1, inode_buffer);
if (retval)
return retval;
if (length) {
retval = io_channel_read_blk(fs->io, ++block_nr, 1,
inode_buffer);
if (retval) {
inode_buffer_block = 0;
return retval;
}
inode_buffer_block = block_nr;
memcpy(inode_buffer, ((char *) &temp_inode) + clen, length);
retval = io_channel_write_blk(fs->io, block_nr, 1,
inode_buffer);
if (retval)
return retval;
}
fs->flags |= EXT2_FLAG_CHANGED;
return 0;
}
errcode_t ext2fs_get_blocks(ext2_filsys fs, ino_t ino, blk_t *blocks)
{
struct ext2_inode inode;
int i;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (ino > fs->super->s_inodes_count)
return EXT2_ET_BAD_INODE_NUM;
if (fs->get_blocks) {
if (!(*fs->get_blocks)(fs, ino, blocks))
return 0;
}
retval = ext2fs_read_inode(fs, ino, &inode);
if (retval)
return retval;
for (i=0; i < EXT2_N_BLOCKS; i++)
blocks[i] = inode.i_block[i];
return 0;
}
errcode_t ext2fs_check_directory(ext2_filsys fs, ino_t ino)
{
struct ext2_inode inode;
errcode_t retval;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (ino > fs->super->s_inodes_count)
return EXT2_ET_BAD_INODE_NUM;
if (fs->check_directory)
return (fs->check_directory)(fs, ino);
retval = ext2fs_read_inode(fs, ino, &inode);
if (retval)
return retval;
if (!LINUX_S_ISDIR(inode.i_mode))
return ENOTDIR;
return 0;
}
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