StdLib/PosixLib/Gen/readdir.c

   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 *
  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 *
  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
 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 }