lib/libc/gen/seekdir.c

   1 /*      $NetBSD: seekdir.c,v 1.15 2013/03/06 11:27:46 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[] = "@(#)seekdir.c   8.1 (Berkeley) 6/4/93";
  36 #else
  37 __RCSID("$NetBSD: seekdir.c,v 1.15 2013/03/06 11:27:46 yamt Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include "reentrant.h"
  43 #include "extern.h"
  44 #include <sys/param.h>
  45
  46 #include <dirent.h>
  47
  48 #include "dirent_private.h"
  49
  50 #ifdef __weak_alias
  51 __weak_alias(seekdir,_seekdir)
  52 #endif
  53
  54 /*
  55  * Seek to an entry in a directory.
  56  * _seekdir_unlocked is in telldir.c so that it can share opaque
  57  * data structures.
  58  */
  59 void
  60 seekdir(DIR *dirp, long loc)
  61 {
  62
  63 #ifdef _REENTRANT
  64         if (__isthreaded) {
  65                 mutex_lock((mutex_t *)dirp->dd_lock);
  66                 _seekdir_unlocked(dirp, loc);
  67                 mutex_unlock((mutex_t *)dirp->dd_lock);
  68         } else
  69 #endif
  70                 _seekdir_unlocked(dirp, loc);
  71 }