1 /* 2 * check_desc.c --- Check the group descriptors of an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12 #include "config.h" 13 #include <stdio.h> 14 #include <string.h> 15 #if HAVE_UNISTD_H 16 #include <unistd.h> 17 #endif 18 #include <fcntl.h> 19 #include <time.h> 20 #if HAVE_SYS_STAT_H 21 #include <sys/stat.h> 22 #endif 23 #if HAVE_SYS_TYPES_H 24 #include <sys/types.h> 25 #endif 26 27 #include "ext2_fs.h" 28 #include "ext2fs.h" 29 30 /* 31 * This routine sanity checks the group descriptors 32 */ 33 errcode_t ext2fs_check_desc(ext2_filsys fs) 34 { 35 ext2fs_block_bitmap bmap; 36 errcode_t retval; 37 dgrp_t i; 38 blk64_t first_block = fs->super->s_first_data_block; 39 blk64_t last_block = ext2fs_blocks_count(fs->super)-1; 40 blk64_t blk, b; 41 unsigned int j; 42 43 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 44 45 if (EXT2_DESC_SIZE(fs->super) & (EXT2_DESC_SIZE(fs->super) - 1)) 46 return EXT2_ET_BAD_DESC_SIZE; 47 48 retval = ext2fs_allocate_subcluster_bitmap(fs, "check_desc map", &bmap); 49 if (retval) 50 return retval; 51 52 for (i = 0; i < fs->group_desc_count; i++) 53 ext2fs_reserve_super_and_bgd(fs, i, bmap); 54 55 for (i = 0; i < fs->group_desc_count; i++) { 56 if (!ext2fs_has_feature_flex_bg(fs->super)) { 57 first_block = ext2fs_group_first_block2(fs, i); 58 last_block = ext2fs_group_last_block2(fs, i); 59 } 60 61 /* 62 * Check to make sure the block bitmap for group is sane 63 */ 64 blk = ext2fs_block_bitmap_loc(fs, i); 65 if (blk < first_block || blk > last_block || 66 ext2fs_test_block_bitmap2(bmap, blk)) { 67 retval = EXT2_ET_GDESC_BAD_BLOCK_MAP; 68 goto errout; 69 } 70 ext2fs_mark_block_bitmap2(bmap, blk); 71 72 /* 73 * Check to make sure the inode bitmap for group is sane 74 */ 75 blk = ext2fs_inode_bitmap_loc(fs, i); 76 if (blk < first_block || blk > last_block || 77 ext2fs_test_block_bitmap2(bmap, blk)) { 78 retval = EXT2_ET_GDESC_BAD_INODE_MAP; 79 goto errout; 80 } 81 ext2fs_mark_block_bitmap2(bmap, blk); 82 83 /* 84 * Check to make sure the inode table for group is sane 85 */ 86 blk = ext2fs_inode_table_loc(fs, i); 87 if (blk < first_block || 88 ((blk + fs->inode_blocks_per_group - 1) > last_block)) { 89 retval = EXT2_ET_GDESC_BAD_INODE_TABLE; 90 goto errout; 91 } 92 for (j = 0, b = blk; j < fs->inode_blocks_per_group; 93 j++, b++) { 94 if (ext2fs_test_block_bitmap2(bmap, b)) { 95 retval = EXT2_ET_GDESC_BAD_INODE_TABLE; 96 goto errout; 97 } 98 ext2fs_mark_block_bitmap2(bmap, b); 99 } 100 } 101 errout: 102 ext2fs_free_block_bitmap(bmap); 103 return retval; 104 }