readdir.c revision 1573 
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)
35static char sccsid[] = "@(#)readdir.c	8.1 (Berkeley) 6/4/93";
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 */
44struct dirent *
45readdir(dirp)
46	register DIR *dirp;
47{
48	register struct dirent *dp;
49
50	for (;;) {
51		if (dirp->dd_loc == 0) {
52			dirp->dd_size = getdirentries(dirp->dd_fd,
53			    dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
54			if (dirp->dd_size <= 0)
55				return NULL;
56		}
57		if (dirp->dd_loc >= dirp->dd_size) {
58			dirp->dd_loc = 0;
59			continue;
60		}
61		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
62		if ((int)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		return (dp);
71	}
72}
73