dirblock.c revision 9f8046fc6dfc13eee2f5c363214e60b533872cac 
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	do_swap = (fs->flags & (EXT2_FLAG_SWAP_BYTES|
35				EXT2_FLAG_SWAP_BYTES_READ)) != 0;
36	p = (char *) buf;
37	end = (char *) buf + fs->blocksize;
38	while (p < end-8) {
39		dirent = (struct ext2_dir_entry *) p;
40		if (do_swap) {
41			dirent->inode = ext2fs_swab32(dirent->inode);
42			dirent->rec_len = ext2fs_swab16(dirent->rec_len);
43			dirent->name_len = ext2fs_swab16(dirent->name_len);
44		}
45		rec_len = dirent->rec_len;
46		if ((rec_len < 8) || (rec_len % 4)) {
47			rec_len = 8;
48			retval = EXT2_ET_DIR_CORRUPTED;
49		}
50		dirent2 = (struct ext2_dir_entry_2 *) dirent;
51		if ((dirent2->name_len +8) > dirent2->rec_len)
52			retval = EXT2_ET_DIR_CORRUPTED;
53		p += rec_len;
54	}
55	return retval;
56}
57
58errcode_t ext2fs_write_dir_block(ext2_filsys fs, blk_t block,
59				 void *inbuf)
60{
61	errcode_t	retval;
62	char		*p, *end, *write_buf;
63	char		*buf = 0;
64	struct ext2_dir_entry *dirent;
65
66	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
67	    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) {
68		retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
69		if (retval)
70			return retval;
71		write_buf = buf;
72		memcpy(buf, inbuf, fs->blocksize);
73		p = buf;
74		end = buf + fs->blocksize;
75		while (p < end) {
76			dirent = (struct ext2_dir_entry *) p;
77			if ((dirent->rec_len < 8) ||
78			    (dirent->rec_len % 4)) {
79				retval = EXT2_ET_DIR_CORRUPTED;
80				goto errout;
81			}
82			p += dirent->rec_len;
83			dirent->inode = ext2fs_swab32(dirent->inode);
84			dirent->rec_len = ext2fs_swab16(dirent->rec_len);
85			dirent->name_len = ext2fs_swab16(dirent->name_len);
86		}
87	} else
88		write_buf = (char *) inbuf;
89 	retval = io_channel_write_blk(fs->io, block, 1, write_buf);
90errout:
91	if (buf)
92		ext2fs_free_mem((void **) &buf);
93	return retval;
94}
95
96
97