1/** @file
2    Open a directory.
3
4    Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>
5    This program and the accompanying materials
6    are licensed and made available under the terms and conditions of the BSD License
7    which accompanies this distribution.  The full text of the license may be found at
8    http://opensource.org/licenses/bsd-license.php
9
10    THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11    WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13    Copyright (c) 1983, 1993
14    The Regents of the University of California.  All rights reserved.
15
16    Redistribution and use in source and binary forms, with or without
17    modification, are permitted provided that the following conditions
18    are met:
19    1. Redistributions of source code must retain the above copyright
20      notice, this list of conditions and the following disclaimer.
21    2. Redistributions in binary form must reproduce the above copyright
22      notice, this list of conditions and the following disclaimer in the
23      documentation and/or other materials provided with the distribution.
24    3. Neither the name of the University nor the names of its contributors
25      may be used to endorse or promote products derived from this software
26      without specific prior written permission.
27
28    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38    SUCH DAMAGE.
39
40    NetBSD: opendir.c,v 1.33 2008/01/10 09:49:04 elad Exp
41    opendir.c 8.7 (Berkeley) 12/10/94
42**/
43#include <sys/cdefs.h>
44
45#include  <namespace.h>
46#include  <reentrant.h>
47#include  <extern.h>
48#include <sys/param.h>
49//#include <sys/mount.h>
50#include <sys/stat.h>
51
52#include <assert.h>
53#include <dirent.h>
54#include <errno.h>
55#include <fcntl.h>
56#include <stdlib.h>
57#include <string.h>
58#include <unistd.h>
59
60#define MAXITERATIONS 100
61
62/*
63 * Open a directory.
64 */
65DIR *
66opendir(const char *name)
67{
68  _DIAGASSERT(name != NULL);
69
70  return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
71}
72
73DIR *
74__opendir2(const char *name, int flags)
75{
76  DIR *dirp = NULL;
77  int fd;
78  int serrno;
79  struct stat sb;
80  int incr;
81
82  _DIAGASSERT(name != NULL);
83
84  if ((fd = open(name, O_RDONLY | O_NONBLOCK, 0)) == -1 ||
85      fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
86    goto error;
87  if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
88    errno = ENOTDIR;
89    goto error;
90  }
91  if ((dirp = (DIR *)malloc(sizeof(DIR))) == NULL)
92    goto error;
93  dirp->dd_buf = NULL;
94
95  /*
96   * If the machine's page size is an exact multiple of DIRBLKSIZ,
97   * use a buffer that is cluster boundary aligned.
98   * Hopefully this can be a big win someday by allowing page trades
99   * to user space to be done by getdirentries()
100   */
101  incr = DIRBLKSIZ;
102
103  dirp->dd_len = incr;
104  dirp->dd_buf = malloc((size_t)dirp->dd_len);
105  if (dirp->dd_buf == NULL)
106    goto error;
107  dirp->dd_seek = 0;
108  flags &= ~DTF_REWIND;
109
110  dirp->dd_loc = 0;
111  dirp->dd_fd = fd;
112  dirp->dd_flags = flags;
113
114  /*
115   * Set up seek point for rewinddir.
116   */
117#ifdef _REENTRANT
118  if (__isthreaded) {
119    if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
120      goto error;
121    mutex_init((mutex_t *)dirp->dd_lock, NULL);
122  }
123#endif
124  dirp->dd_internal = NULL;
125  return (dirp);
126error:
127  serrno = errno;
128  if (dirp && dirp->dd_buf)
129    free(dirp->dd_buf);
130  if (dirp)
131    free(dirp);
132  if (fd != -1)
133    (void)close(fd);
134  errno = serrno;
135  return NULL;
136}
137