1 /*
2 * dirblock.c --- directory block routines.
3 *
4 * Copyright (C) 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 #if HAVE_UNISTD_H
14 #include <unistd.h>
15 #endif
16 #include <string.h>
17 #include <time.h>
18
19 #include "ext2_fs.h"
20 #include "ext2fs.h"
21
ext2fs_read_dir_block2(ext2_filsys fs,blk_t block,void * buf,int flags EXT2FS_ATTR ((unused)))22 errcode_t ext2fs_read_dir_block2(ext2_filsys fs, blk_t block,
23 void *buf, int flags EXT2FS_ATTR((unused)))
24 {
25 errcode_t retval;
26 char *p, *end;
27 struct ext2_dir_entry *dirent;
28 unsigned int name_len, rec_len, do_swap;
29
30
31 retval = io_channel_read_blk(fs->io, block, 1, buf);
32 if (retval)
33 return retval;
34 #ifdef EXT2FS_ENABLE_SWAPFS
35 do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
36 EXT2_FLAG_SWAP_BYTES_READ)) != 0;
37 #endif
38 p = (char *) buf;
39 end = (char *) buf + fs->blocksize;
40 while (p < end-8) {
41 dirent = (struct ext2_dir_entry *) p;
42 #ifdef EXT2FS_ENABLE_SWAPFS
43 if (do_swap) {
44 dirent->inode = ext2fs_swab32(dirent->inode);
45 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
46 dirent->name_len = ext2fs_swab16(dirent->name_len);
47 }
48 #endif
49 name_len = dirent->name_len;
50 #ifdef WORDS_BIGENDIAN
51 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
52 dirent->name_len = ext2fs_swab16(dirent->name_len);
53 #endif
54 rec_len = dirent->rec_len;
55 if ((rec_len < 8) || (rec_len % 4)) {
56 rec_len = 8;
57 retval = EXT2_ET_DIR_CORRUPTED;
58 }
59 if (((name_len & 0xFF) + 8) > dirent->rec_len)
60 retval = EXT2_ET_DIR_CORRUPTED;
61 p += rec_len;
62 }
63 return retval;
64 }
65
ext2fs_read_dir_block(ext2_filsys fs,blk_t block,void * buf)66 errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
67 void *buf)
68 {
69 return ext2fs_read_dir_block2(fs, block, buf, 0);
70 }
71
72
ext2fs_write_dir_block2(ext2_filsys fs,blk_t block,void * inbuf,int flags EXT2FS_ATTR ((unused)))73 errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
74 void *inbuf, int flags EXT2FS_ATTR((unused)))
75 {
76 #ifdef EXT2FS_ENABLE_SWAPFS
77 int do_swap = 0;
78 errcode_t retval;
79 char *p, *end;
80 char *buf = 0;
81 struct ext2_dir_entry *dirent;
82
83 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
84 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
85 do_swap = 1;
86
87 #ifndef WORDS_BIGENDIAN
88 if (!do_swap)
89 return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
90 #endif
91
92 retval = ext2fs_get_mem(fs->blocksize, &buf);
93 if (retval)
94 return retval;
95 memcpy(buf, inbuf, fs->blocksize);
96 p = buf;
97 end = buf + fs->blocksize;
98 while (p < end) {
99 dirent = (struct ext2_dir_entry *) p;
100 if ((dirent->rec_len < 8) ||
101 (dirent->rec_len % 4)) {
102 ext2fs_free_mem(&buf);
103 return (EXT2_ET_DIR_CORRUPTED);
104 }
105 p += dirent->rec_len;
106 if (do_swap) {
107 dirent->inode = ext2fs_swab32(dirent->inode);
108 dirent->rec_len = ext2fs_swab16(dirent->rec_len);
109 dirent->name_len = ext2fs_swab16(dirent->name_len);
110 }
111 #ifdef WORDS_BIGENDIAN
112 if (flags & EXT2_DIRBLOCK_V2_STRUCT)
113 dirent->name_len = ext2fs_swab16(dirent->name_len);
114 #endif
115 }
116 retval = io_channel_write_blk(fs->io, block, 1, buf);
117 ext2fs_free_mem(&buf);
118 return retval;
119 #else
120 return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
121 #endif
122 }
123
124
ext2fs_write_dir_block(ext2_filsys fs,blk_t block,void * inbuf)125 errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
126 void *inbuf)
127 {
128 return ext2fs_write_dir_block2(fs, block, inbuf, 0);
129 }
130
131