1 /* $OpenBSD: opendir.c,v 1.31 2024/04/15 15:47:58 florian 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/types.h>
32 #include <sys/stat.h>
33
34 #include <dirent.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39
40 #include "telldir.h"
41
42
43 /*
44 * Open a directory specified by name.
45 */
46 DIR *
opendir(const char * name)47 opendir(const char *name)
48 {
49 DIR *dirp;
50 int fd;
51
52 if ((fd = open(name, O_RDONLY | O_DIRECTORY | O_CLOEXEC)) == -1)
53 return (NULL);
54 dirp = __fdopendir(fd);
55 if (dirp == NULL)
56 close(fd);
57 return (dirp);
58 }
59 DEF_WEAK(opendir);
60
61 /*
62 * Open a directory specified by file descriptor.
63 */
64 DIR *
fdopendir(int fd)65 fdopendir(int fd)
66 {
67 DIR *dirp;
68 int flags;
69
70 if ((flags = fcntl(fd, F_GETFL)) == -1)
71 return (NULL);
72 if ((flags & O_ACCMODE) != O_RDONLY && (flags & O_ACCMODE) != O_RDWR) {
73 errno = EBADF;
74 return (NULL);
75 }
76 dirp = __fdopendir(fd);
77 if (dirp != NULL) {
78 /* Record current offset for immediate telldir() */
79 dirp->dd_bufpos = dirp->dd_curpos = lseek(fd, 0, SEEK_CUR);
80
81 /*
82 * POSIX doesn't require fdopendir() to set
83 * FD_CLOEXEC, so it's okay for this to fail.
84 */
85 (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
86 }
87 return (dirp);
88 }
89 DEF_WEAK(fdopendir);
90
91 DIR *
__fdopendir(int fd)92 __fdopendir(int fd)
93 {
94 DIR *dirp;
95 struct stat sb;
96 int pageoffset;
97
98 if (fstat(fd, &sb))
99 return (NULL);
100 if (!S_ISDIR(sb.st_mode)) {
101 errno = ENOTDIR;
102 return (NULL);
103 }
104 if ((dirp = malloc(sizeof(DIR))) == NULL)
105 return (NULL);
106
107 pageoffset = getpagesize() - 1;
108 dirp->dd_len = ((int)sb.st_blksize * 4 + pageoffset) & ~pageoffset;
109 dirp->dd_buf = malloc(dirp->dd_len);
110 if (dirp->dd_buf == NULL) {
111 free(dirp);
112 return (NULL);
113 }
114
115 dirp->dd_size = 0;
116 dirp->dd_loc = 0;
117 dirp->dd_fd = fd;
118 dirp->dd_lock = NULL;
119 dirp->dd_curpos = 0;
120 dirp->dd_bufpos = 0;
121
122 return (dirp);
123 }
124