readdir.c revision 270002 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/10/lib/libc/gen/readdir.c 270002 2014-08-14 20:20:21Z jhb $");
35
36#include "namespace.h"
37#include <sys/param.h>
38#include <dirent.h>
39#include <errno.h>
40#include <string.h>
41#include <pthread.h>
42#include "un-namespace.h"
43
44#include "libc_private.h"
45#include "gen-private.h"
46#include "telldir.h"
47
48/*
49 * get next entry in a directory.
50 */
51struct dirent *
52_readdir_unlocked(dirp, skip)
53	DIR *dirp;
54	int skip;
55{
56	struct dirent *dp;
57
58	for (;;) {
59		if (dirp->dd_loc >= dirp->dd_size) {
60			if (dirp->dd_flags & __DTF_READALL)
61				return (NULL);
62			dirp->dd_loc = 0;
63		}
64		if (dirp->dd_loc == 0 &&
65		    !(dirp->dd_flags & (__DTF_READALL | __DTF_SKIPREAD))) {
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		dirp->dd_flags &= ~__DTF_SKIPREAD;
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 && skip)
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(&dirp->dd_lock);
95		dp = _readdir_unlocked(dirp, 1);
96		_pthread_mutex_unlock(&dirp->dd_lock);
97	}
98	else
99		dp = _readdir_unlocked(dirp, 1);
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(&dirp->dd_lock);
116		if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
117			memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
118		_pthread_mutex_unlock(&dirp->dd_lock);
119	}
120	else if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
121		memcpy(entry, dp, _GENERIC_DIRSIZ(dp));
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