xref: /netbsd-src/lib/libc/gen/readdir.c (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: readdir.c,v 1.5 1995/02/25 08:51:35 cgd 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
39 #else
40 static char rcsid[] = "$NetBSD: readdir.c,v 1.5 1995/02/25 08:51:35 cgd Exp $";
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43 
44 #include <sys/param.h>
45 #include <dirent.h>
46 
47 /*
48  * get next entry in a directory.
49  */
50 struct dirent *
51 readdir(dirp)
52 	register DIR *dirp;
53 {
54 	register struct dirent *dp;
55 
56 	for (;;) {
57 		if (dirp->dd_loc >= dirp->dd_size) {
58 			if (dirp->dd_flags & __DTF_READALL)
59 				return (NULL);
60 			dirp->dd_loc = 0;
61 		}
62 		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
63 			dirp->dd_size = getdirentries(dirp->dd_fd,
64 			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
65 			if (dirp->dd_size <= 0)
66 				return (NULL);
67 		}
68 		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
69 		if ((long)dp & 03)	/* bogus pointer check */
70 			return (NULL);
71 		if (dp->d_reclen <= 0 ||
72 		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
73 			return (NULL);
74 		dirp->dd_loc += dp->d_reclen;
75 		if (dp->d_ino == 0)
76 			continue;
77 		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
78 			continue;
79 		return (dp);
80 	}
81 }
82