xref: /freebsd/lib/libc/gen/readdir.c (revision a8445737e740901f5f2c8d24c12ef7fc8b00134e)
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 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)readdir.c	8.3 (Berkeley) 9/29/94";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/param.h>
39 #include <dirent.h>
40 
41 /*
42  * get next entry in a directory.
43  */
44 struct dirent *
45 readdir(dirp)
46 	register DIR *dirp;
47 {
48 	register struct dirent *dp;
49 
50 	for (;;) {
51 		if (dirp->dd_loc >= dirp->dd_size) {
52 			if (dirp->dd_flags & __DTF_READALL)
53 				return (NULL);
54 			dirp->dd_loc = 0;
55 		}
56 		if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
57 			dirp->dd_size = getdirentries(dirp->dd_fd,
58 			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
59 			if (dirp->dd_size <= 0)
60 				return (NULL);
61 		}
62 		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
63 		if ((long)dp & 03L)	/* bogus pointer check */
64 			return (NULL);
65 		if (dp->d_reclen <= 0 ||
66 		    dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
67 			return (NULL);
68 		dirp->dd_loc += dp->d_reclen;
69 		if (dp->d_ino == 0)
70 			continue;
71 		if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
72 			continue;
73 		return (dp);
74 	}
75 }
76