dirblock.c revision bfcd9a116ff3bcc6d94a616ab1444eb38d0d5434 
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#if EXT2_FLAT_INCLUDES
20#include "ext2_fs.h"
21#else
22#include <linux/ext2_fs.h>
23#endif
24
25#include "ext2fs.h"
26
27errcode_t ext2fs_read_dir_block(ext2_filsys fs, blk_t block,
28				void *buf)
29{
30	errcode_t	retval;
31	char		*p, *end;
32	struct ext2_dir_entry *dirent;
33	struct ext2_dir_entry_2 *dirent2;
34	unsigned int	rec_len, do_swap;
35
36 	retval = io_channel_read_blk(fs->io, block, 1, buf);
37	if (retval)
38		return retval;
39	do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
40				EXT2_FLAG_SWAP_BYTES_READ)) != 0;
41	p = (char *) buf;
42	end = (char *) buf + fs->blocksize;
43	while (p < end-8) {
44		dirent = (struct ext2_dir_entry *) p;
45		if (do_swap) {
46			dirent->inode = ext2fs_swab32(dirent->inode);
47			dirent->rec_len = ext2fs_swab16(dirent->rec_len);
48			dirent->name_len = ext2fs_swab16(dirent->name_len);
49		}
50		rec_len = dirent->rec_len;
51		if ((rec_len < 8) || (rec_len % 4)) {
52			rec_len = 8;
53			retval = EXT2_ET_DIR_CORRUPTED;
54		}
55		dirent2 = (struct ext2_dir_entry_2 *) dirent;
56		if ((dirent2->name_len +8) > dirent2->rec_len)
57			retval = EXT2_ET_DIR_CORRUPTED;
58		p += rec_len;
59	}
60	return retval;
61}
62
63errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
64				 void *inbuf)
65{
66	errcode_t	retval;
67	char		*p, *end, *write_buf;
68	char		*buf = 0;
69	struct ext2_dir_entry *dirent;
70
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		write_buf = (char *) inbuf;
94 	retval = io_channel_write_blk(fs->io, block, 1, write_buf);
95errout:
96	if (buf)
97		ext2fs_free_mem((void **) &buf);
98	return retval;
99}
100
101
102