newlib/libc/posix/readdir_r.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 /* this code is modified from readdir.c by Jeff Johnston, June 5, 2002 */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)readdir.c   5.7 (Berkeley) 6/1/90";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <dirent.h>
  39 #include <errno.h>
  40 #include <string.h>
  41 #include <sys/param.h>
  42
  43 extern int getdents (int fd, void *dp, int count);
  44
  45 /*
  46  * get next entry in a directory using supplied dirent structure.
  47  */
  48 int
  49 readdir_r (register DIR *__restrict dirp,
  50         struct dirent *__restrict dp,
  51         struct dirent **__restrict dpp) {
  52
  53 struct dirent *tmpdp;
  54
  55 #ifdef HAVE_DD_LOCK
  56   __lock_acquire_recursive(dirp->dd_lock);
  57 #endif
  58
  59   for (;;) {
  60     if (dirp->dd_loc == 0) {
  61       dirp->dd_size = getdents (dirp->dd_fd,
  62                                 dirp->dd_buf,
  63                                 dirp->dd_len);
  64
  65       if (dirp->dd_size <= 0) {
  66 #ifdef HAVE_DD_LOCK
  67         __lock_release_recursive(dirp->dd_lock);
  68 #endif
  69         *dpp = NULL;
  70         return dirp->dd_size == 0 ? 0 : errno;
  71       }
  72     }
  73     if (dirp->dd_loc >= dirp->dd_size) {
  74       dirp->dd_loc = 0;
  75       continue;
  76     }
  77     tmpdp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  78
  79     if (tmpdp->d_reclen <= 0 ||
  80         tmpdp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc) {
  81 #ifdef HAVE_DD_LOCK
  82       __lock_release_recursive(dirp->dd_lock);
  83 #endif
  84       *dpp = NULL;
  85       return -1;
  86     }
  87     memcpy (dp, tmpdp, MIN (tmpdp->d_reclen, sizeof (struct dirent)));
  88
  89     dirp->dd_loc += dp->d_reclen;
  90     if (dp->d_ino == 0)
  91       continue;
  92 #ifdef HAVE_DD_LOCK
  93     __lock_release_recursive(dirp->dd_lock);
  94 #endif
  95     *dpp = dp;
  96     return 0;
  97   }
  98 }
  99
 100 #endif /* ! HAVE_OPENDIR */