dirblock.c revision 5df55d7f847e29d23227592a0bb23daad1a61500 
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_block(ext2_filsys fs, blk_t block,
23				void *buf)
24{
25	errcode_t	retval;
26	char		*p, *end;
27	struct ext2_dir_entry *dirent;
28	struct ext2_dir_entry_2 *dirent2;
29	unsigned int	rec_len, do_swap;
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		rec_len = dirent->rec_len;
50		if ((rec_len < 8) || (rec_len % 4)) {
51			rec_len = 8;
52			retval = EXT2_ET_DIR_CORRUPTED;
53		}
54		dirent2 = (struct ext2_dir_entry_2 *) dirent;
55		if ((dirent2->name_len +8) > dirent2->rec_len)
56			retval = EXT2_ET_DIR_CORRUPTED;
57		p += rec_len;
58	}
59	return retval;
60}
61
62errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
63				 void *inbuf)
64{
65	errcode_t	retval;
66	char		*p, *end, *write_buf;
67	char		*buf = 0;
68	struct ext2_dir_entry *dirent;
69
70#ifdef EXT2FS_ENABLE_SWAPFS
71	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
72	    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) {
73		retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
74		if (retval)
75			return retval;
76		write_buf = buf;
77		memcpy(buf, inbuf, fs->blocksize);
78		p = buf;
79		end = buf + fs->blocksize;
80		while (p < end) {
81			dirent = (struct ext2_dir_entry *) p;
82			if ((dirent->rec_len < 8) ||
83			    (dirent->rec_len % 4)) {
84				retval = EXT2_ET_DIR_CORRUPTED;
85				goto errout;
86			}
87			p += dirent->rec_len;
88			dirent->inode = ext2fs_swab32(dirent->inode);
89			dirent->rec_len = ext2fs_swab16(dirent->rec_len);
90			dirent->name_len = ext2fs_swab16(dirent->name_len);
91		}
92	} else
93#endif
94		write_buf = (char *) inbuf;
95 	retval = io_channel_write_blk(fs->io, block, 1, write_buf);
96errout:
97	if (buf)
98		ext2fs_free_mem((void **) &buf);
99	return retval;
100}
101
102
103