lib/libc/gen/readdir.c

   1 /*      $NetBSD: readdir.c,v 1.25 2010/09/16 02:38:50 yamt Exp $        */
   2
   3 /*
   4  * Copyright (c) 1983, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)readdir.c   8.3 (Berkeley) 9/29/94";
  36 #else
  37 __RCSID("$NetBSD: readdir.c,v 1.25 2010/09/16 02:38:50 yamt Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include "reentrant.h"
  43
  44 #ifdef __minix
  45 #include <sys/cdefs.h>
  46 #include <sys/types.h>
  47 #endif
  48
  49 #include "extern.h"
  50 #include <sys/param.h>
  51
  52 #include <dirent.h>
  53 #include <errno.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56
  57 #include "dirent_private.h"
  58
  59 /*
  60  * get next entry in a directory.
  61  */
  62 struct dirent *
  63 _readdir_unlocked(DIR *dirp, int skipdeleted)
  64 {
  65         struct dirent *dp;
  66
  67         for (;;) {
  68                 if (dirp->dd_loc >= dirp->dd_size) {
  69                         if (dirp->dd_flags & __DTF_READALL)
  70                                 return (NULL);
  71                         dirp->dd_loc = 0;
  72                 }
  73                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  74                         dirp->dd_seek = lseek(dirp->dd_fd, (off_t)0, SEEK_CUR);
  75                         dirp->dd_size = getdents(dirp->dd_fd,
  76                             dirp->dd_buf, (size_t)dirp->dd_len);
  77                         if (dirp->dd_size <= 0)
  78                                 return (NULL);
  79                 }
  80                 dp = (struct dirent *)
  81                     (void *)(dirp->dd_buf + (size_t)dirp->dd_loc);
  82                 if ((intptr_t)dp & _DIRENT_ALIGN(dp))/* bogus pointer check */
  83                         return (NULL);
  84                 /* d_reclen is unsigned; no need to compare it <= 0 */
  85                 if (dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
  86                         return (NULL);
  87                 dirp->dd_loc += dp->d_reclen;
  88                 if (dp->d_ino == 0 && skipdeleted)
  89                         continue;
  90 #ifndef __minix
  91                 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  92                         continue;
  93 #endif
  94                 return (dp);
  95         }
  96 }
  97
  98 struct dirent *
  99 readdir(dirp)
 100         DIR *dirp;
 101 {
 102         struct dirent   *dp;
 103
 104 #ifdef _REENTRANT
 105         if (__isthreaded) {
 106                 mutex_lock((mutex_t *)dirp->dd_lock);
 107                 dp = _readdir_unlocked(dirp, 1);
 108                 mutex_unlock((mutex_t *)dirp->dd_lock);
 109         }
 110         else
 111 #endif
 112                 dp = _readdir_unlocked(dirp, 1);
 113         return (dp);
 114 }
 115
 116 int
 117 readdir_r(dirp, entry, result)
 118         DIR *dirp;
 119         struct dirent *entry;
 120         struct dirent **result;
 121 {
 122         struct dirent *dp;
 123         int saved_errno;
 124
 125         saved_errno = errno;
 126         errno = 0;
 127 #ifdef _REENTRANT
 128         if (__isthreaded) {
 129                 mutex_lock((mutex_t *)dirp->dd_lock);
 130                 if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 131                         memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
 132                 mutex_unlock((mutex_t *)dirp->dd_lock);
 133         }
 134         else
 135 #endif
 136                 if ((dp = _readdir_unlocked(dirp, 1)) != NULL)
 137                         memcpy(entry, dp, (size_t)_DIRENT_SIZE(dp));
 138
 139         if (errno != 0) {
 140                 if (dp == NULL)
 141                         return (errno);
 142         } else
 143                 errno = saved_errno;
 144
 145         if (dp != NULL)
 146                 *result = entry;
 147         else
 148                 *result = NULL;
 149
 150         return (0);
 151 }