| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 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 (!EXT2_HAS_INCOMPAT_FEATURE(fs->super, |
| 57 | EXT4_FEATURE_INCOMPAT_FLEX_BG)) { |
| 58 | first_block = ext2fs_group_first_block2(fs, i); |
| 59 | last_block = ext2fs_group_last_block2(fs, i); |
| 60 | } |
| 61 | |
| 62 | /* |
| 63 | * Check to make sure the block bitmap for group is sane |
| 64 | */ |
| 65 | blk = ext2fs_block_bitmap_loc(fs, i); |
| 66 | if (blk < first_block || blk > last_block || |
| 67 | ext2fs_test_block_bitmap2(bmap, blk)) { |
| 68 | retval = EXT2_ET_GDESC_BAD_BLOCK_MAP; |
| 69 | goto errout; |
| 70 | } |
| 71 | ext2fs_mark_block_bitmap2(bmap, blk); |
| 72 | |
| 73 | /* |
| 74 | * Check to make sure the inode bitmap for group is sane |
| 75 | */ |
| 76 | blk = ext2fs_inode_bitmap_loc(fs, i); |
| 77 | if (blk < first_block || blk > last_block || |
| 78 | ext2fs_test_block_bitmap2(bmap, blk)) { |
| 79 | retval = EXT2_ET_GDESC_BAD_INODE_MAP; |
| 80 | goto errout; |
| 81 | } |
| 82 | ext2fs_mark_block_bitmap2(bmap, blk); |
| 83 | |
| 84 | /* |
| 85 | * Check to make sure the inode table for group is sane |
| 86 | */ |
| 87 | blk = ext2fs_inode_table_loc(fs, i); |
| 88 | if (blk < first_block || |
| 89 | ((blk + fs->inode_blocks_per_group - 1) > last_block)) { |
| 90 | retval = EXT2_ET_GDESC_BAD_INODE_TABLE; |
| 91 | goto errout; |
| 92 | } |
| 93 | for (j = 0, b = blk; j < fs->inode_blocks_per_group; |
| 94 | j++, b++) { |
| 95 | if (ext2fs_test_block_bitmap2(bmap, b)) { |
| 96 | retval = EXT2_ET_GDESC_BAD_INODE_TABLE; |
| 97 | goto errout; |
| 98 | } |
| 99 | ext2fs_mark_block_bitmap2(bmap, b); |
| 100 | } |
| 101 | } |
| 102 | errout: |
| 103 | ext2fs_free_block_bitmap(bmap); |
| 104 | return retval; |
| 105 | } |