1 /* $OpenBSD: opendir.c,v 1.14 2005/08/08 08:05:34 espie Exp $ */
2 /*
3 * Copyright (c) 1983, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/param.h>
32 #include <sys/mount.h>
33 #include <sys/stat.h>
34
35 #include <dirent.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <limits.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42
43 /*
44 * Open a directory.
45 */
46 DIR *
opendir(const char * name)47 opendir(const char *name)
48 {
49
50 return (__opendir2(name, DTF_NODUP));
51 }
52
53 DIR *
__opendir2(const char * name,int flags)54 __opendir2(const char *name, int flags)
55 {
56 DIR *dirp;
57 int fd;
58 struct stat sb;
59 int pagesz;
60 int incr;
61
62 if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1)
63 return (NULL);
64 if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
65 close(fd);
66 errno = ENOTDIR;
67 return (NULL);
68 }
69 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
70 (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
71 close(fd);
72 return (NULL);
73 }
74
75 /*
76 * If the machine's page size is an exact multiple of DIRBLKSIZ,
77 * use a buffer that is cluster boundary aligned.
78 * Hopefully this can be a big win someday by allowing page trades
79 * to user space to be done by getdirentries()
80 */
81 if (((pagesz = getpagesize()) % DIRBLKSIZ) == 0)
82 incr = pagesz;
83 else
84 incr = DIRBLKSIZ;
85
86 dirp->dd_len = incr;
87 dirp->dd_buf = malloc(dirp->dd_len);
88 if (dirp->dd_buf == NULL) {
89 free(dirp);
90 close (fd);
91 return (NULL);
92 }
93
94 dirp->dd_seek = 0;
95 dirp->dd_loc = 0;
96 dirp->dd_fd = fd;
97 dirp->dd_flags = flags;
98
99 /*
100 * Set up seek point for rewinddir.
101 */
102 dirp->dd_rewind = telldir(dirp);
103
104 return (dirp);
105 }
106