[821] | 1 | /*
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| 2 | * dirblock.c --- directory block routines.
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| 3 | *
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| 4 | * Copyright (C) 1995, 1996 Theodore Ts'o.
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| 5 | *
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| 6 | * %Begin-Header%
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| 7 | * This file may be redistributed under the terms of the GNU Public
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| 8 | * License.
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| 9 | * %End-Header%
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| 10 | */
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| 11 |
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| 12 | #include <stdio.h>
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| 13 | #if HAVE_UNISTD_H
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| 14 | #include <unistd.h>
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| 15 | #endif
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| 16 | #include <string.h>
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| 17 | #include <time.h>
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| 18 |
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| 19 | #include "ext2_fs.h"
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| 20 | #include "ext2fs.h"
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| 21 |
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| 22 | errcode_t ext2fs_read_dir_block2(ext2_filsys fs, blk_t block,
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| 23 | void *buf, int flags EXT2FS_ATTR((unused)))
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| 24 | {
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| 25 | errcode_t retval;
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| 26 | char *p, *end;
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| 27 | struct ext2_dir_entry *dirent;
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| 28 | unsigned int name_len, rec_len;
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| 29 | #if BB_BIG_ENDIAN
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| 30 | unsigned int do_swap;
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| 31 | #endif
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| 32 |
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| 33 | retval = io_channel_read_blk(fs->io, block, 1, buf);
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| 34 | if (retval)
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| 35 | return retval;
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| 36 | #if BB_BIG_ENDIAN
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| 37 | do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
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| 38 | EXT2_FLAG_SWAP_BYTES_READ)) != 0;
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| 39 | #endif
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| 40 | p = (char *) buf;
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| 41 | end = (char *) buf + fs->blocksize;
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| 42 | while (p < end-8) {
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| 43 | dirent = (struct ext2_dir_entry *) p;
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| 44 | #if BB_BIG_ENDIAN
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| 45 | if (do_swap) {
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| 46 | dirent->inode = ext2fs_swab32(dirent->inode);
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| 47 | dirent->rec_len = ext2fs_swab16(dirent->rec_len);
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| 48 | dirent->name_len = ext2fs_swab16(dirent->name_len);
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| 49 | }
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| 50 | #endif
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| 51 | name_len = dirent->name_len;
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| 52 | #ifdef WORDS_BIGENDIAN
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| 53 | if (flags & EXT2_DIRBLOCK_V2_STRUCT)
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| 54 | dirent->name_len = ext2fs_swab16(dirent->name_len);
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| 55 | #endif
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| 56 | rec_len = dirent->rec_len;
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| 57 | if ((rec_len < 8) || (rec_len % 4)) {
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| 58 | rec_len = 8;
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| 59 | retval = EXT2_ET_DIR_CORRUPTED;
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| 60 | }
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| 61 | if (((name_len & 0xFF) + 8) > dirent->rec_len)
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| 62 | retval = EXT2_ET_DIR_CORRUPTED;
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| 63 | p += rec_len;
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| 64 | }
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| 65 | return retval;
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| 66 | }
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| 67 |
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| 68 | errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
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| 69 | void *buf)
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| 70 | {
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| 71 | return ext2fs_read_dir_block2(fs, block, buf, 0);
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| 72 | }
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| 73 |
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| 74 |
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| 75 | errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
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| 76 | void *inbuf, int flags EXT2FS_ATTR((unused)))
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| 77 | {
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| 78 | #if BB_BIG_ENDIAN
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| 79 | int do_swap = 0;
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| 80 | errcode_t retval;
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| 81 | char *p, *end;
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| 82 | char *buf = 0;
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| 83 | struct ext2_dir_entry *dirent;
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| 84 |
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| 85 | if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
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| 86 | (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
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| 87 | do_swap = 1;
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| 88 |
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| 89 | #ifndef WORDS_BIGENDIAN
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| 90 | if (!do_swap)
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| 91 | return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
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| 92 | #endif
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| 93 |
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| 94 | retval = ext2fs_get_mem(fs->blocksize, &buf);
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| 95 | if (retval)
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| 96 | return retval;
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| 97 | memcpy(buf, inbuf, fs->blocksize);
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| 98 | p = buf;
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| 99 | end = buf + fs->blocksize;
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| 100 | while (p < end) {
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| 101 | dirent = (struct ext2_dir_entry *) p;
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| 102 | if ((dirent->rec_len < 8) ||
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| 103 | (dirent->rec_len % 4)) {
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| 104 | ext2fs_free_mem(&buf);
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| 105 | return (EXT2_ET_DIR_CORRUPTED);
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| 106 | }
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| 107 | p += dirent->rec_len;
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| 108 | if (do_swap) {
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| 109 | dirent->inode = ext2fs_swab32(dirent->inode);
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| 110 | dirent->rec_len = ext2fs_swab16(dirent->rec_len);
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| 111 | dirent->name_len = ext2fs_swab16(dirent->name_len);
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| 112 | }
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| 113 | #ifdef WORDS_BIGENDIAN
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| 114 | if (flags & EXT2_DIRBLOCK_V2_STRUCT)
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| 115 | dirent->name_len = ext2fs_swab16(dirent->name_len);
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| 116 | #endif
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| 117 | }
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| 118 | retval = io_channel_write_blk(fs->io, block, 1, buf);
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| 119 | ext2fs_free_mem(&buf);
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| 120 | return retval;
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| 121 | #else
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| 122 | return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
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| 123 | #endif
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| 124 | }
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| 125 |
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| 126 |
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| 127 | errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
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| 128 | void *inbuf)
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| 129 | {
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| 130 | return ext2fs_write_dir_block2(fs, block, inbuf, 0);
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| 131 | }
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| 132 |
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