readdir.c revision 71579 
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: head/lib/libc/gen/readdir.c 71579 2001-01-24 13:01:12Z deischen $
34 *
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
39#endif /* LIBC_SCCS and not lint */
40
41#include "namespace.h"
42#include <sys/param.h>
43#include <dirent.h>
44#include <errno.h>
45#include <string.h>
46#include <pthread.h>
47#include "un-namespace.h"
48
49#include "libc_private.h"
50
51/*
52 * get next entry in a directory.
53 */
54struct dirent *
55_readdir_unlocked(dirp)
56	DIR *dirp;
57{
58	struct dirent *dp;
59
60	for (;;) {
61		if (dirp->dd_loc >= dirp->dd_size) {
62			if (dirp->dd_flags & __DTF_READALL)
63				return (NULL);
64			dirp->dd_loc = 0;
65		}
66		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
67			dirp->dd_size = _getdirentries(dirp->dd_fd,
68			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
69			if (dirp->dd_size <= 0)
70				return (NULL);
71		}
72		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
73		if ((long)dp & 03L)	/* bogus pointer check */
74			return (NULL);
75		if (dp->d_reclen <= 0 ||
76		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
77			return (NULL);
78		dirp->dd_loc += dp->d_reclen;
79		if (dp->d_ino == 0)
80			continue;
81		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
82			continue;
83		return (dp);
84	}
85}
86
87struct dirent *
88readdir(dirp)
89	DIR *dirp;
90{
91	struct dirent	*dp;
92
93	if (__isthreaded) {
94		_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
95		dp = _readdir_unlocked(dirp);
96		_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
97	}
98	else
99		dp = _readdir_unlocked(dirp);
100	return (dp);
101}
102
103int
104readdir_r(dirp, entry, result)
105	DIR *dirp;
106	struct dirent *entry;
107	struct dirent **result;
108{
109	struct dirent *dp;
110	int saved_errno;
111
112	saved_errno = errno;
113	errno = 0;
114	if (__isthreaded) {
115		_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
116		if ((dp = _readdir_unlocked(dirp)) != NULL)
117			memcpy(entry, dp, sizeof *entry);
118		_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
119	}
120	else if ((dp = _readdir_unlocked(dirp)) != NULL)
121		memcpy(entry, dp, sizeof *entry);
122
123	if (errno != 0) {
124		if (dp == NULL)
125			return (errno);
126	} else
127		errno = saved_errno;
128
129	if (dp != NULL)
130		*result = entry;
131	else
132		*result = NULL;
133
134	return (0);
135}
136