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 1.10 2008/05/03 22:07:37 dillon Exp $
  35  *
  36  * @(#)readdir.c        8.3 (Berkeley) 9/29/94
  37  */
  38
  39 #include "namespace.h"
  40 #include <sys/param.h>
  41 #include <sys/file.h>
  42 #include <dirent.h>
  43 #include <errno.h>
  44 #include <string.h>
  45 #include <pthread.h>
  46 #include "un-namespace.h"
  47
  48 #include "libc_private.h"
  49
  50 /*
  51  * get next entry in a directory.
  52  */
  53 struct dirent *
  54 _readdir_unlocked(DIR *dirp, int skipdeleted)
  55 {
  56         struct dirent *dp;
  57         long dummy;
  58
  59         for (;;) {
  60                 if (dirp->dd_loc >= dirp->dd_size) {
  61                         if (dirp->dd_flags & __DTF_READALL)
  62                                 return (NULL);
  63                         dirp->dd_loc = 0;
  64                 }
  65                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  66                         dirp->dd_seek = lseek(dirp->dd_fd, 0, SEEK_CUR);
  67                         dirp->dd_size = _getdirentries(dirp->dd_fd,
  68                             dirp->dd_buf, dirp->dd_len, &dummy);
  69                         if (dirp->dd_size <= 0)
  70                                 return (NULL);
  71                 }
  72                 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  73                 if (_DIRENT_DIRSIZ(dp) > dirp->dd_len + 1 - dirp->dd_loc)
  74                         return (NULL);
  75                 dirp->dd_loc += _DIRENT_DIRSIZ(dp);
  76
  77                 if (skipdeleted) {
  78                         if (dp->d_ino == 0)
  79                                 continue;
  80                         if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  81                                 continue;
  82                 }
  83                 return (dp);
  84         }
  85 }
  86
  87 struct dirent *
  88 readdir(DIR *dirp)
  89 {
  90         struct dirent   *dp;
  91
  92         if (__isthreaded)
  93                 _pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
  94         dp = _readdir_unlocked(dirp, 1);
  95         if (__isthreaded)
  96                 _pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
  97
  98         return (dp);
  99 }
 100
 101 int
 102 readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
 103 {
 104         struct dirent *dp;
 105         int saved_errno;
 106
 107         saved_errno = errno;
 108         errno = 0;
 109         if (__isthreaded)
 110                 _pthread_mutex_lock((pthread_mutex_t *)&dirp->dd_lock);
 111         if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 112                 memcpy(entry, dp, _DIRENT_MINSIZ(dp));
 113         if (__isthreaded)
 114                 _pthread_mutex_unlock((pthread_mutex_t *)&dirp->dd_lock);
 115
 116         if (errno != 0) {
 117                 if (dp == NULL) {
 118                         return (errno);
 119                 }
 120         } else
 121                 errno = saved_errno;
 122
 123         if (dp != NULL)
 124                 *result = entry;
 125         else
 126                 *result = NULL;
 127
 128         return (0);
 129 }