1 /* $NetBSD: readdir.c,v 1.26 2012/06/25 22:32:43 abs 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
35 static char sccsid[] = "@(#)readdir.c 8.3 (Berkeley) 9/29/94";
36 #else
37 __RCSID("$NetBSD: readdir.c,v 1.26 2012/06/25 22:32:43 abs 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 */
56 struct dirent *
_readdir_unlocked(DIR * dirp,int skipdeleted)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
90 struct dirent *
readdir(DIR * dirp)91 readdir(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
107 int
readdir_r(DIR * dirp,struct dirent * entry,struct dirent ** result)108 readdir_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