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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/lib/libc/gen/readdir.c,v 1.5.2.4 2002/02/26 22:53:57 alfred Exp $
  30  *
  31  * @(#)readdir.c        8.3 (Berkeley) 9/29/94
  32  */
  33
  34 #include "namespace.h"
  35 #include <sys/param.h>
  36 #include <sys/file.h>
  37 #include <dirent.h>
  38 #include <errno.h>
  39 #include <string.h>
  40 #include <pthread.h>
  41 #include "un-namespace.h"
  42
  43 #include "libc_private.h"
  44 #include "gen_private.h"
  45
  46 /*
  47  * get next entry in a directory.
  48  */
  49 struct dirent *
  50 _readdir_unlocked(DIR *dirp, int skipdeleted)
  51 {
  52         struct dirent *dp;
  53         long dummy;
  54
  55         for (;;) {
  56                 if (dirp->dd_loc >= dirp->dd_size) {
  57                         if (dirp->dd_flags & __DTF_READALL)
  58                                 return (NULL);
  59                         dirp->dd_loc = 0;
  60                 }
  61                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  62                         dirp->dd_seek = lseek(dirp->dd_fd, 0, SEEK_CUR);
  63                         dirp->dd_size = _getdirentries(dirp->dd_fd,
  64                             dirp->dd_buf, dirp->dd_len, &dummy);
  65                         if (dirp->dd_size <= 0)
  66                                 return (NULL);
  67                 }
  68                 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  69                 if (_DIRENT_DIRSIZ(dp) > dirp->dd_len + 1 - dirp->dd_loc)
  70                         return (NULL);
  71                 dirp->dd_loc += _DIRENT_DIRSIZ(dp);
  72
  73                 if (skipdeleted) {
  74                         if (dp->d_ino == 0)
  75                                 continue;
  76                         if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  77                                 continue;
  78                 }
  79                 return (dp);
  80         }
  81 }
  82
  83 struct dirent *
  84 readdir(DIR *dirp)
  85 {
  86         struct dirent   *dp;
  87
  88         if (__isthreaded)
  89                 _pthread_mutex_lock(&dirp->dd_lock);
  90         dp = _readdir_unlocked(dirp, 1);
  91         if (__isthreaded)
  92                 _pthread_mutex_unlock(&dirp->dd_lock);
  93
  94         return (dp);
  95 }
  96
  97 int
  98 readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
  99 {
 100         struct dirent *dp;
 101         int saved_errno;
 102
 103         saved_errno = errno;
 104         errno = 0;
 105         if (__isthreaded)
 106                 _pthread_mutex_lock(&dirp->dd_lock);
 107         if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 108                 memcpy(entry, dp, _DIRENT_MINSIZ(dp));
 109         if (__isthreaded)
 110                 _pthread_mutex_unlock(&dirp->dd_lock);
 111
 112         if (errno != 0) {
 113                 if (dp == NULL) {
 114                         return (errno);
 115                 }
 116         } else
 117                 errno = saved_errno;
 118
 119         if (dp != NULL)
 120                 *result = entry;
 121         else
 122                 *result = NULL;
 123
 124         return (0);
 125 }