lib/libc/gen/readdir.c

   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/readdir.c,v 1.5.2.4 2002/02/26 22:53:57 alfred Exp $
  34  * $DragonFly: src/lib/libc/gen/readdir.c,v 1.8 2005/11/19 22:32:53 swildner Exp $
  35  *
  36  * @(#)readdir.c        8.3 (Berkeley) 9/29/94
  37  */
  38
  39 #include "namespace.h"
  40 #include <sys/param.h>
  41 #include <dirent.h>
  42 #include <errno.h>
  43 #include <string.h>
  44 #include <pthread.h>
  45 #include "un-namespace.h"
  46
  47 #include "libc_private.h"
  48
  49 /*
  50  * get next entry in a directory.
  51  */
  52 struct dirent *
  53 _readdir_unlocked(DIR *dirp)
  54 {
  55         struct dirent *dp;
  56
  57         for (;;) {
  58                 if (dirp->dd_loc >= dirp->dd_size) {
  59                         if (dirp->dd_flags & __DTF_READALL)
  60                                 return (NULL);
  61                         dirp->dd_loc = 0;
  62                 }
  63                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  64                         dirp->dd_size = _getdirentries(dirp->dd_fd,
  65                             dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
  66                         if (dirp->dd_size <= 0)
  67                                 return (NULL);
  68                 }
  69                 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  70                 if (_DIRENT_DIRSIZ(dp) > dirp->dd_len + 1 - dirp->dd_loc)
  71                         return (NULL);
  72                 dirp->dd_loc += _DIRENT_DIRSIZ(dp);
  73                 if (dp->d_ino == 0)
  74                         continue;
  75                 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  76                         continue;
  77                 return (dp);
  78         }
  79 }
  80
  81 struct dirent *
  82 readdir(DIR *dirp)
  83 {
  84         struct dirent   *dp;
  85
  86         if (__isthreaded)
  87                 _pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
  88         dp = _readdir_unlocked(dirp);
  89         if (__isthreaded)
  90                 _pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
  91
  92         return (dp);
  93 }
  94
  95 int
  96 readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
  97 {
  98         struct dirent *dp;
  99         int saved_errno;
 100
 101         saved_errno = errno;
 102         errno = 0;
 103         if (__isthreaded)
 104                 _pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
 105         if ((dp = _readdir_unlocked(dirp)) != NULL)
 106                 memcpy(entry, dp, _DIRENT_MINSIZ(dp));
 107         if (__isthreaded)
 108                 _pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
 109
 110         if (errno != 0) {
 111                 if (dp == NULL) {
 112                         return (errno);
 113                 }
 114         } else
 115                 errno = saved_errno;
 116
 117         if (dp != NULL)
 118                 *result = entry;
 119         else
 120                 *result = NULL;
 121
 122         return (0);
 123 }