readdir.c revision 61193 
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 61193 2000-06-03 00:27:54Z kris $
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 <sys/param.h>
42#include <dirent.h>
43#include <errno.h>
44#include <string.h>
45#ifdef _THREAD_SAFE
46#include <pthread.h>
47#include "pthread_private.h"
48#endif _THREAD_SAFE
49
50/*
51 * get next entry in a directory.
52 */
53struct dirent *
54readdir(dirp)
55	register DIR *dirp;
56{
57	register struct dirent *dp;
58
59	for (;;) {
60		if (dirp->dd_loc >= dirp->dd_size) {
61			if (dirp->dd_flags & __DTF_READALL)
62				return (NULL);
63			dirp->dd_loc = 0;
64		}
65		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
66			dirp->dd_size = getdirentries(dirp->dd_fd,
67			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
68			if (dirp->dd_size <= 0)
69				return (NULL);
70		}
71		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
72		if ((long)dp & 03L)	/* bogus pointer check */
73			return (NULL);
74		if (dp->d_reclen <= 0 ||
75		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
76			return (NULL);
77		dirp->dd_loc += dp->d_reclen;
78		if (dp->d_ino == 0)
79			continue;
80		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
81			continue;
82		return (dp);
83	}
84}
85
86int
87readdir_r(dirp, entry, result)
88	DIR *dirp;
89	struct dirent *entry;
90	struct dirent **result;
91{
92	struct dirent *dp;
93	int ret, saved_errno;
94
95#ifdef _THREAD_SAFE
96	if ((ret = _FD_LOCK(dirp->dd_fd, FD_READ, NULL)) != 0)
97		return (ret);
98#endif
99
100	saved_errno = errno;
101	errno = 0;
102	dp = readdir(dirp);
103	if (errno != 0) {
104		if (dp == NULL) {
105#ifdef _THREAD_SAFE
106			_FD_UNLOCK(dirp->dd_fd, FD_READ);
107#endif
108			return (errno);
109		}
110	} else
111		errno = saved_errno;
112
113	if (dp != NULL)
114		memcpy(entry, dp, sizeof *entry);
115
116#ifdef _THREAD_SAFE
117	_FD_UNLOCK(dirp->dd_fd, FD_READ);
118#endif
119
120	if (dp != NULL)
121		*result = entry;
122	else
123		*result = NULL;
124
125	return (0);
126}
127