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 <unistd.h>
  42 #include "un-namespace.h"
  43
  44 #include "libc_private.h"
  45 #include "gen_private.h"
  46
  47 /*
  48  * get next entry in a directory.
  49  */
  50 struct dirent *
  51 _readdir_unlocked(DIR *dirp, int skipdeleted)
  52 {
  53         struct dirent *dp;
  54         long dummy;
  55
  56         for (;;) {
  57                 if (dirp->dd_loc >= dirp->dd_size) {
  58                         if (dirp->dd_flags & __DTF_READALL)
  59                                 return (NULL);
  60                         dirp->dd_loc = 0;
  61                 }
  62                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  63                         dirp->dd_seek = lseek(dirp->dd_fd, 0, SEEK_CUR);
  64                         dirp->dd_size = _getdirentries(dirp->dd_fd,
  65                             dirp->dd_buf, dirp->dd_len, &dummy);
  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
  74                 if (skipdeleted) {
  75                         if (dp->d_ino == 0)
  76                                 continue;
  77                         if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  78                                 continue;
  79                 }
  80                 return (dp);
  81         }
  82 }
  83
  84 struct dirent *
  85 readdir(DIR *dirp)
  86 {
  87         struct dirent   *dp;
  88
  89         if (__isthreaded)
  90                 _pthread_mutex_lock(&dirp->dd_lock);
  91         dp = _readdir_unlocked(dirp, 1);
  92         if (__isthreaded)
  93                 _pthread_mutex_unlock(&dirp->dd_lock);
  94
  95         return (dp);
  96 }
  97
  98 int
  99 readdir_r(DIR * __restrict dirp, struct dirent * __restrict entry,
 100     struct dirent ** __restrict result)
 101 {
 102         struct dirent *dp;
 103         int saved_errno;
 104
 105         saved_errno = errno;
 106         errno = 0;
 107         if (__isthreaded)
 108                 _pthread_mutex_lock(&dirp->dd_lock);
 109         if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 110                 memcpy(entry, dp, _DIRENT_MINSIZ(dp));
 111         if (__isthreaded)
 112                 _pthread_mutex_unlock(&dirp->dd_lock);
 113
 114         if (errno != 0) {
 115                 if (dp == NULL) {
 116                         return (errno);
 117                 }
 118         } else
 119                 errno = saved_errno;
 120
 121         if (dp != NULL)
 122                 *result = entry;
 123         else
 124                 *result = NULL;
 125
 126         return (0);
 127 }