1/*	$NetBSD: readdir.c,v 1.25 2010/09/16 02:38:50 yamt Exp $	*/
2
3/*
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
36#else
37__RCSID("$NetBSD: readdir.c,v 1.25 2010/09/16 02:38:50 yamt Exp $");
38#endif
39#endif /* LIBC_SCCS and not lint */
40
41#include "namespace.h"
42#include "reentrant.h"
43#include "extern.h"
44#include <sys/param.h>
45
46#include <dirent.h>
47#include <errno.h>
48#include <string.h>
49#include <unistd.h>
50
51#include "dirent_private.h"
52
53/*
54 * get next entry in a directory.
55 */
56struct dirent *
57_readdir_unlocked(DIR *dirp, int skipdeleted)
58{
59	struct dirent *dp;
60
61	for (;;) {
62		if (dirp->dd_loc >= dirp->dd_size) {
63			if (dirp->dd_flags & __DTF_READALL)
64				return (NULL);
65			dirp->dd_loc = 0;
66		}
67		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
68			dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR);
69			dirp->dd_size = getdents(dirp->dd_fd,
70			    dirp->dd_buf, (size_t)dirp->dd_len);
71			if (dirp->dd_size <= 0)
72				return (NULL);
73		}
74		dp = (struct dirent *)
75		    (void *)(dirp->dd_buf + (size_t)dirp->dd_loc);
76		if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */
77			return (NULL);
78		/* d_reclen is unsigned; no need to compare it <= 0 */
79		if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
80			return (NULL);
81		dirp->dd_loc += dp->d_reclen;
82		if (dp->d_ino == 0 && skipdeleted)
83			continue;
84		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
85			continue;
86		return (dp);
87	}
88}
89
90struct dirent *
91readdir(DIR *dirp)
92{
93	struct dirent	*dp;
94
95#ifdef _REENTRANT
96	if (__isthreaded) {
97		mutex_lock((mutex_t *)dirp->dd_lock);
98		dp = _readdir_unlocked(dirp, 1);
99		mutex_unlock((mutex_t *)dirp->dd_lock);
100	}
101	else
102#endif
103		dp = _readdir_unlocked(dirp, 1);
104	return (dp);
105}
106
107int
108readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
109{
110	struct dirent *dp;
111	int saved_errno;
112
113	saved_errno = errno;
114	errno = 0;
115#ifdef _REENTRANT
116	if (__isthreaded) {
117		mutex_lock((mutex_t *)dirp->dd_lock);
118		if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
119			memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
120		mutex_unlock((mutex_t *)dirp->dd_lock);
121	}
122	else
123#endif
124		if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
125			memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
126
127	if (errno != 0) {
128		if (dp == NULL)
129			return (errno);
130	} else
131		errno = saved_errno;
132
133	if (dp != NULL)
134		*result = entry;
135	else
136		*result = NULL;
137
138	return (0);
139}
140