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/*
* check_desc.c --- Check the group descriptors of an ext2 filesystem
*
* Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include "config.h"
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <time.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include "ext2_fs.h"
#include "ext2fs.h"
/*
* This routine sanity checks the group descriptors
*/
errcode_t ext2fs_check_desc(ext2_filsys fs)
{
ext2fs_block_bitmap bmap;
errcode_t retval;
dgrp_t i;
blk64_t first_block = fs->super->s_first_data_block;
blk64_t last_block = ext2fs_blocks_count(fs->super)-1;
blk64_t blk, b;
unsigned int j;
EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
if (EXT2_DESC_SIZE(fs->super) & (EXT2_DESC_SIZE(fs->super) - 1))
return EXT2_ET_BAD_DESC_SIZE;
retval = ext2fs_allocate_subcluster_bitmap(fs, "check_desc map", &bmap);
if (retval)
return retval;
for (i = 0; i < fs->group_desc_count; i++)
ext2fs_reserve_super_and_bgd(fs, i, bmap);
for (i = 0; i < fs->group_desc_count; i++) {
if (!ext2fs_has_feature_flex_bg(fs->super)) {
first_block = ext2fs_group_first_block2(fs, i);
last_block = ext2fs_group_last_block2(fs, i);
}
/*
* Check to make sure the block bitmap for group is sane
*/
blk = ext2fs_block_bitmap_loc(fs, i);
if (blk < first_block || blk > last_block ||
ext2fs_test_block_bitmap2(bmap, blk)) {
retval = EXT2_ET_GDESC_BAD_BLOCK_MAP;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, blk);
/*
* Check to make sure the inode bitmap for group is sane
*/
blk = ext2fs_inode_bitmap_loc(fs, i);
if (blk < first_block || blk > last_block ||
ext2fs_test_block_bitmap2(bmap, blk)) {
retval = EXT2_ET_GDESC_BAD_INODE_MAP;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, blk);
/*
* Check to make sure the inode table for group is sane
*/
blk = ext2fs_inode_table_loc(fs, i);
if (blk < first_block ||
((blk + fs->inode_blocks_per_group - 1) > last_block)) {
retval = EXT2_ET_GDESC_BAD_INODE_TABLE;
goto errout;
}
for (j = 0, b = blk; j < fs->inode_blocks_per_group;
j++, b++) {
if (ext2fs_test_block_bitmap2(bmap, b)) {
retval = EXT2_ET_GDESC_BAD_INODE_TABLE;
goto errout;
}
ext2fs_mark_block_bitmap2(bmap, b);
}
}
errout:
ext2fs_free_block_bitmap(bmap);
return retval;
}
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