xref: /freebsd/lib/libc/gen/readdir.c (revision 6990ffd8a95caaba6858ad44ff1b3157d1efba8f)
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  * $FreeBSD$
34  *
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static 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  */
54 struct 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 
87 struct dirent *
88 readdir(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 
103 int
104 readdir_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