newlib/libc/posix/readdir.c

   1 #ifndef HAVE_OPENDIR
   2
   3 /*
   4  * Copyright (c) 1983 Regents of the University of California.
   5  * 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 #if defined(LIBC_SCCS) && !defined(lint)
  33 static char sccsid[] = "@(#)readdir.c   5.7 (Berkeley) 6/1/90";
  34 #endif /* LIBC_SCCS and not lint */
  35
  36 #include <dirent.h>
  37
  38 extern int getdents (int fd, void *dp, int count);
  39
  40 /*
  41  * get next entry in a directory.
  42  */
  43 struct dirent *
  44 readdir (register DIR *dirp)
  45 {
  46   register struct dirent *dp;
  47
  48 #ifdef HAVE_DD_LOCK
  49   __lock_acquire_recursive(dirp->dd_lock);
  50 #endif
  51
  52   for (;;) {
  53     if (dirp->dd_loc == 0) {
  54       dirp->dd_size = getdents (dirp->dd_fd,
  55                                 dirp->dd_buf,
  56                                 dirp->dd_len);
  57
  58       if (dirp->dd_size <= 0) {
  59 #ifdef HAVE_DD_LOCK
  60         __lock_release_recursive(dirp->dd_lock);
  61 #endif
  62         return NULL;
  63       }
  64     }
  65     if (dirp->dd_loc >= dirp->dd_size) {
  66       dirp->dd_loc = 0;
  67       continue;
  68     }
  69     dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  70     if (dp->d_reclen <= 0 ||
  71         dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) {
  72 #ifdef HAVE_DD_LOCK
  73       __lock_release_recursive(dirp->dd_lock);
  74 #endif
  75       return NULL;
  76     }
  77     dirp->dd_loc += dp->d_reclen;
  78     if (dp->d_ino == 0)
  79       continue;
  80 #ifdef HAVE_DD_LOCK
  81     __lock_release_recursive(dirp->dd_lock);
  82 #endif
  83     return (dp);
  84   }
  85 }
  86
  87 #endif /* ! HAVE_OPENDIR */