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 Public 8 * License. 9 * %End-Header% 10 */ 11 12 #include <stdio.h> 13 #include <string.h> 14 #if HAVE_UNISTD_H 15 #include <unistd.h> 16 #endif 17 #include <fcntl.h> 18 #include <time.h> 19 #if HAVE_SYS_STAT_H 20 #include <sys/stat.h> 21 #endif 22 #if HAVE_SYS_TYPES_H 23 #include <sys/types.h> 24 #endif 25 26 #include "ext2_fs.h" 27 #include "ext2fs.h" 28 29 /* 30 * This routine sanity checks the group descriptors 31 */ 32 errcode_t ext2fs_check_desc(ext2_filsys fs) 33 { 34 ext2fs_block_bitmap bmap; 35 errcode_t retval; 36 dgrp_t i; 37 blk_t first_block = fs->super->s_first_data_block; 38 blk_t last_block = fs->super->s_blocks_count-1; 39 blk_t blk, b; 40 int j; 41 42 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 43 44 retval = ext2fs_allocate_block_bitmap(fs, "check_desc map", &bmap); 45 if (retval) 46 return retval; 47 48 for (i = 0; i < fs->group_desc_count; i++) 49 ext2fs_reserve_super_and_bgd(fs, i, bmap); 50 51 for (i = 0; i < fs->group_desc_count; i++) { 52 if (!EXT2_HAS_INCOMPAT_FEATURE(fs->super, 53 EXT4_FEATURE_INCOMPAT_FLEX_BG)) { 54 first_block = ext2fs_group_first_block(fs, i); 55 last_block = ext2fs_group_last_block(fs, i); 56 if (i == (fs->group_desc_count - 1)) 57 last_block = fs->super->s_blocks_count-1; 58 } 59 60 /* 61 * Check to make sure the block bitmap for group is sane 62 */ 63 blk = fs->group_desc[i].bg_block_bitmap; 64 if (blk < first_block || blk > last_block || 65 ext2fs_test_block_bitmap(bmap, blk)) { 66 retval = EXT2_ET_GDESC_BAD_BLOCK_MAP; 67 goto errout; 68 } 69 ext2fs_mark_block_bitmap(bmap, blk); 70 71 /* 72 * Check to make sure the inode bitmap for group is sane 73 */ 74 blk = fs->group_desc[i].bg_inode_bitmap; 75 if (blk < first_block || blk > last_block || 76 ext2fs_test_block_bitmap(bmap, blk)) { 77 retval = EXT2_ET_GDESC_BAD_INODE_MAP; 78 goto errout; 79 } 80 ext2fs_mark_block_bitmap(bmap, blk); 81 82 /* 83 * Check to make sure the inode table for group is sane 84 */ 85 blk = fs->group_desc[i].bg_inode_table; 86 if (blk < first_block || 87 ((blk + fs->inode_blocks_per_group - 1) > last_block)) { 88 retval = EXT2_ET_GDESC_BAD_INODE_TABLE; 89 goto errout; 90 } 91 for (j = 0, b = blk; j < fs->inode_blocks_per_group; 92 j++, b++) { 93 if (ext2fs_test_block_bitmap(bmap, b)) { 94 retval = EXT2_ET_GDESC_BAD_INODE_TABLE; 95 goto errout; 96 } 97 ext2fs_mark_block_bitmap(bmap, b); 98 } 99 } 100 errout: 101 ext2fs_free_block_bitmap(bmap); 102 return retval; 103 } 104