1/** @file
2    Get next entry in 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: readdir.c,v 1.24 2008/05/04 18:53:26 tonnerre Exp
41    readdir.c 8.3 (Berkeley) 9/29/94
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/stdint.h>
50
51#include  <stdio.h>
52#include <dirent.h>
53#include <errno.h>
54#include <string.h>
55#include <unistd.h>
56
57/*
58 * get next entry in a directory.
59 */
60struct dirent *
61_readdir_unlocked(DIR *dirp, int skipdeleted)
62{
63  struct dirent *dp;
64
65
66  for (;;) {
67    if (dirp->dd_loc >= dirp->dd_size) {
68      if (dirp->dd_flags & __DTF_READALL)
69        return (NULL);
70      dirp->dd_loc = 0;
71    }
72    if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
73      dirp->dd_size = (long)read(dirp->dd_fd, dirp->dd_buf, (size_t)dirp->dd_len);
74      if (dirp->dd_size <= 0)
75        return (NULL);
76    }
77    dp = (struct dirent *) (void *)(dirp->dd_buf + (size_t)dirp->dd_loc);
78    if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */
79      return (NULL);
80    dirp->dd_loc += (long)dp->Size;
81    if ((dp->Attribute & DT_HIDDEN) && (dirp->dd_flags & DTF_HIDEW))
82      continue;
83    return (dp);
84  }
85}
86
87struct dirent *
88readdir(DIR *dirp)
89{
90  struct dirent *dp;
91
92#ifdef _REENTRANT
93  if (__isthreaded) {
94    mutex_lock((mutex_t *)dirp->dd_lock);
95    dp = _readdir_unlocked(dirp, 1);
96    mutex_unlock((mutex_t *)dirp->dd_lock);
97  }
98  else
99#endif
100    dp = _readdir_unlocked(dirp, 1);
101  return (dp);
102}
103
104int
105readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
106{
107  struct dirent *dp;
108  int saved_errno;
109
110  saved_errno = errno;
111  errno = 0;
112#ifdef _REENTRANT
113  if (__isthreaded) {
114    mutex_lock((mutex_t *)dirp->dd_lock);
115    if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
116      memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
117    mutex_unlock((mutex_t *)dirp->dd_lock);
118  }
119  else
120#endif
121    if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
122      memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
123
124  if (errno != 0) {
125    if (dp == NULL)
126      return (errno);
127  } else
128    errno = saved_errno;
129
130  if (dp != NULL)
131    *result = entry;
132  else
133    *result = NULL;
134
135  return (0);
136}
137