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  */
60 struct dirent *
_readdir_unlocked(DIR * dirp,int skipdeleted)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 
87 struct dirent *
readdir(DIR * dirp)88 readdir(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 
104 int
readdir_r(DIR * dirp,struct dirent * entry,struct dirent ** result)105 readdir_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