1/*	$OpenBSD: readdir.c,v 1.22 2015/09/12 13:34:22 guenther Exp $ */
2/*
3 * Copyright (c) 1983, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <dirent.h>
32#include <errno.h>
33#include "telldir.h"
34#include "thread_private.h"
35
36/*
37 * get next entry in a directory.
38 */
39int
40_readdir_unlocked(DIR *dirp, struct dirent **result)
41{
42	struct dirent *dp;
43
44	*result = NULL;
45	for (;;) {
46		if (dirp->dd_loc >= dirp->dd_size) {
47			dirp->dd_loc = 0;
48			dirp->dd_size = getdents(dirp->dd_fd, dirp->dd_buf,
49			    dirp->dd_len);
50			if (dirp->dd_size == 0)
51				return (0);
52			if (dirp->dd_size < 0)
53				return (-1);
54		}
55		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
56		if ((long)dp & 03 ||	/* bogus pointer check */
57		    dp->d_reclen <= 0 ||
58		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) {
59			errno = EINVAL;
60			return (-1);
61		}
62		dirp->dd_loc += dp->d_reclen;
63		if (dp->d_ino == 0)
64			continue;
65		dirp->dd_curpos = dp->d_off;
66		*result = dp;
67		return (0);
68	}
69}
70
71struct dirent *
72readdir(DIR *dirp)
73{
74	struct dirent *dp;
75
76	_MUTEX_LOCK(&dirp->dd_lock);
77	_readdir_unlocked(dirp, &dp);
78	_MUTEX_UNLOCK(&dirp->dd_lock);
79
80	return (dp);
81}
82DEF_WEAK(readdir);
83