opendir.c revision 1574 
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[] = "@(#)opendir.c	8.2 (Berkeley) 2/12/94";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39
40#include <dirent.h>
41#include <fcntl.h>
42#include <stdlib.h>
43#include <unistd.h>
44
45/*
46 * open a directory.
47 */
48DIR *
49opendir(name)
50	const char *name;
51{
52	register DIR *dirp;
53	register int fd;
54
55	if ((fd = open(name, 0)) == -1)
56		return NULL;
57	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
58	    (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
59		close (fd);
60		return NULL;
61	}
62	/*
63	 * If CLBYTES is an exact multiple of DIRBLKSIZ, use a CLBYTES
64	 * buffer that it cluster boundary aligned.
65	 * Hopefully this can be a big win someday by allowing page trades
66	 * to user space to be done by getdirentries()
67	 */
68	if ((CLBYTES % DIRBLKSIZ) == 0) {
69		dirp->dd_buf = malloc(CLBYTES);
70		dirp->dd_len = CLBYTES;
71	} else {
72		dirp->dd_buf = malloc(DIRBLKSIZ);
73		dirp->dd_len = DIRBLKSIZ;
74	}
75	if (dirp->dd_buf == NULL) {
76		close (fd);
77		return NULL;
78	}
79	dirp->dd_fd = fd;
80	dirp->dd_loc = 0;
81	dirp->dd_seek = 0;
82	/*
83	 * Set up seek point for rewinddir.
84	 */
85	dirp->dd_rewind = telldir(dirp);
86	return dirp;
87}
88