xref: /openbsd-src/lib/libc/gen/readdir.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
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. 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)
31 static char rcsid[] = "$OpenBSD: readdir.c,v 1.6 2003/06/02 20:18:34 millert Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <sys/param.h>
35 #include <dirent.h>
36 #include <string.h>
37 #include <errno.h>
38 #include "thread_private.h"
39 
40 /*
41  * get next entry in a directory.
42  */
43 struct dirent *
44 readdir(dirp)
45 	register DIR *dirp;
46 {
47 	register struct dirent *dp;
48 
49 	for (;;) {
50 		if (dirp->dd_loc >= dirp->dd_size) {
51 			if (dirp->dd_flags & __DTF_READALL)
52 				return (NULL);
53 			dirp->dd_loc = 0;
54 		}
55 		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
56 			dirp->dd_size = getdirentries(dirp->dd_fd,
57 			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
58 			if (dirp->dd_size <= 0)
59 				return (NULL);
60 		}
61 		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
62 		if ((long)dp & 03)	/* bogus pointer check */
63 			return (NULL);
64 		if (dp->d_reclen <= 0 ||
65 		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
66 			return (NULL);
67 		dirp->dd_loc += dp->d_reclen;
68 		if (dp->d_ino == 0)
69 			continue;
70 		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
71 			continue;
72 		return (dp);
73 	}
74 }
75 
76 int
77 readdir_r(dirp, entry, result)
78 	DIR *dirp;
79 	struct dirent *entry;
80 	struct dirent **result;
81 {
82 	struct dirent *dp;
83 	int ret;
84 
85 	if (dirp->dd_fd < 0) {
86 		return EBADF;
87 	}
88 	if ((ret = _FD_LOCK(dirp->dd_fd, FD_READ, NULL)) != 0)
89 		return ret;
90 	errno = 0;
91 	dp = readdir(dirp);
92 	if (dp == NULL && errno != 0) {
93 		_FD_UNLOCK(dirp->dd_fd, FD_READ);
94 		return errno;
95 	}
96 	if (dp != NULL)
97 		memcpy(entry, dp, sizeof (struct dirent) - MAXNAMLEN + dp->d_namlen);
98 	_FD_UNLOCK(dirp->dd_fd, FD_READ);
99 	if (dp != NULL)
100 	*result = entry;
101 	else
102 		*result = NULL;
103 	return 0;
104 }
105