add fdopendir(3) implementation (1/?)
[dragonfly.git] / lib / libc / gen / opendir.c
CommitLineData
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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 * $FreeBSD: src/lib/libc/gen/opendir.c,v 1.10.2.1 2001/06/04 20:59:48 joerg Exp $
0f52d283 34 * $DragonFly: src/lib/libc/gen/opendir.c,v 1.6 2005/11/13 00:07:42 swildner Exp $
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35 *
36 * @(#)opendir.c 8.8 (Berkeley) 5/1/95
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37 */
38
17ea2221 39#include "namespace.h"
984263bc 40#include <sys/param.h>
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41#include <sys/stat.h>
42
43#include <dirent.h>
44#include <errno.h>
45#include <fcntl.h>
46#include <stdlib.h>
4cb07007 47#include <string.h>
984263bc 48#include <unistd.h>
17ea2221 49#include "un-namespace.h"
984263bc 50
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51
52#define DEFAULT_FLAGS (DTF_HIDEW | DTF_NODUP)
53
984263bc 54/*
7385abbc 55 * Open a directory given its path.
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56 */
57DIR *
4cb07007 58opendir(const char *name)
984263bc 59{
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60 return (__opendir2(name, DEFAULT_FLAGS));
61}
62
63/*
64 * Open a directory given a descriptor representing it.
65 */
66DIR *
67fdopendir(int fd)
68{
69 return (__fdopendir2(fd, DEFAULT_FLAGS));
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70}
71
72DIR *
4cb07007 73__opendir2(const char *name, int flags)
984263bc 74{
984263bc 75 int fd;
984263bc 76 struct stat statb;
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77 DIR *dirp;
78 int saved_errno;
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79
80 /*
17ea2221 81 * stat() before _open() because opening of special files may be
7385abbc 82 * harmful.
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83 */
84 if (stat(name, &statb) != 0)
85 return (NULL);
86 if (!S_ISDIR(statb.st_mode)) {
87 errno = ENOTDIR;
88 return (NULL);
89 }
7385abbc 90
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91 if ((fd = _open(name, O_RDONLY | O_NONBLOCK)) == -1)
92 return (NULL);
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93 dirp = __fdopendir2(fd, flags);
94 if (dirp == NULL) {
95 saved_errno = errno;
96 _close(fd);
97 errno = saved_errno;
98 }
99
100 return (dirp);
101}
102
103DIR *
104__fdopendir2(int fd, int flags)
105{
106 DIR *dirp;
107 int incr;
108 int saved_errno;
109 struct stat statb;
110 off_t off;
111
984263bc 112 dirp = NULL;
7385abbc 113
17ea2221 114 if (_fstat(fd, &statb) != 0)
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115 goto fail;
116 if (!S_ISDIR(statb.st_mode)) {
117 errno = ENOTDIR;
118 goto fail;
119 }
120 if (_fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
121 (dirp = malloc(sizeof(DIR))) == NULL)
122 goto fail;
123
124 /*
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125 * XXX We don't support yet the POSIX requirement that states that the
126 * file offset associated with the fd passed to fdopendir() determines
127 * which directory entry is returned.
128 */
129 if ((off = lseek(fd, 0, SEEK_CUR)) != 0) {
130 errno = (off != -1) ? ENOTSUP : errno;
131 goto fail;
132 }
133
134 /*
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135 * Use the system page size if that is a multiple of DIRBLKSIZ.
136 * Hopefully this can be a big win someday by allowing page
17ea2221 137 * trades to user space to be done by _getdirentries().
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138 */
139 incr = getpagesize();
140 if ((incr % DIRBLKSIZ) != 0)
141 incr = DIRBLKSIZ;
142
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143 dirp->dd_len = incr;
144 dirp->dd_buf = malloc(dirp->dd_len);
145 if (dirp->dd_buf == NULL)
146 goto fail;
147 dirp->dd_seek = 0;
148 flags &= ~DTF_REWIND;
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149
150 dirp->dd_loc = 0;
151 dirp->dd_fd = fd;
152 dirp->dd_flags = flags;
17ea2221 153 dirp->dd_lock = NULL;
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154
155 /*
156 * Set up seek point for rewinddir.
157 */
158 dirp->dd_rewind = telldir(dirp);
159
160 return (dirp);
161
162fail:
163 saved_errno = errno;
164 free(dirp);
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165 errno = saved_errno;
166 return (NULL);
167}