dirblock.c revision f9190c8a95c6b76eac567d5896b3ed06ed2a3ada 
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
22errcode_t ext2fs_read_dir_block2(ext2_filsys fs, blk_t block,
23				 void *buf, int flags)
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
66errcode_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
73errcode_t ext2fs_write_dir_block2(ext2_filsys fs, blk_t block,
74				  void *inbuf, int flags)
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, (void **) &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((void **) &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((void **) &buf);
118	return retval;
119#else
120 	return io_channel_write_blk(fs->io, block, 1, (char *) inbuf);
121#endif
122}
123
124
125errcode_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