xref: /dragonfly/lib/libc/gen/readdir.c (revision 2ee85085)
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: src/lib/libc/gen/readdir.c,v 1.5.2.4 2002/02/26 22:53:57 alfred Exp $
34  * $DragonFly: src/lib/libc/gen/readdir.c,v 1.4 2005/02/08 04:07:57 drhodus Exp $
35  *
36  * @(#)readdir.c	8.3 (Berkeley) 9/29/94
37  */
38 
39 #include "namespace.h"
40 #include <sys/param.h>
41 #include <dirent.h>
42 #include <errno.h>
43 #include <string.h>
44 #include <pthread.h>
45 #include "un-namespace.h"
46 
47 #include "libc_private.h"
48 
49 /*
50  * get next entry in a directory.
51  */
52 struct dirent *
53 _readdir_unlocked(dirp)
54 	DIR *dirp;
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 && !(dirp->dd_flags & __DTF_READALL)) {
65 			dirp->dd_size = _getdirentries(dirp->dd_fd,
66 			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
67 			if (dirp->dd_size <= 0)
68 				return (NULL);
69 		}
70 		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
71 		if ((long)dp & 03L)	/* bogus pointer check */
72 			return (NULL);
73 		if (dp->d_reclen <= 0 ||
74 		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
75 			return (NULL);
76 		dirp->dd_loc += dp->d_reclen;
77 		if (dp->d_ino == 0)
78 			continue;
79 		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
80 			continue;
81 		return (dp);
82 	}
83 }
84 
85 struct dirent *
86 readdir(dirp)
87 	DIR *dirp;
88 {
89 	struct dirent	*dp;
90 
91 	if (__isthreaded) {
92 		_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
93 		dp = _readdir_unlocked(dirp);
94 		_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
95 	}
96 	else
97 		dp = _readdir_unlocked(dirp);
98 	return (dp);
99 }
100 
101 int
102 readdir_r(dirp, entry, result)
103 	DIR *dirp;
104 	struct dirent *entry;
105 	struct dirent **result;
106 {
107 	struct dirent *dp;
108 	int ret, saved_errno;
109 
110 	saved_errno = errno;
111 	errno = 0;
112 	if (__isthreaded) {
113 		_pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
114 		if ((dp = _readdir_unlocked(dirp)) != NULL)
115 			memcpy(entry, dp, sizeof *entry);
116 		_pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
117 	}
118 	else if ((dp = _readdir_unlocked(dirp)) != NULL)
119 		memcpy(entry, dp, sizeof *entry);
120 
121 	if (errno != 0) {
122 		if (dp == NULL) {
123 			return (errno);
124 		}
125 	} else
126 		errno = saved_errno;
127 
128 	if (dp != NULL)
129 		*result = entry;
130 	else
131 		*result = NULL;
132 
133 	return (0);
134 }
135