distrib/utils/libhack/opendir.c

   1 /*      $NetBSD: opendir.c,v 1.3 2001/06/15 17:26:51 tsutsui 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
  34 #ifdef __weak_alias
  35 #define opendir                 _opendir
  36 #endif
  37
  38 #include <sys/param.h>
  39 #include <sys/mount.h>
  40 #include <sys/stat.h>
  41
  42 #include <dirent.h>
  43 #include <errno.h>
  44 #include <fcntl.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 #ifdef __weak_alias
  50 __weak_alias(opendir,_opendir)
  51 #endif
  52
  53 /*
  54  * Open a directory.
  55  */
  56 DIR *
  57 opendir(name)
  58         const char *name;
  59 {
  60         DIR *dirp;
  61         int fd;
  62         struct stat sb;
  63
  64         if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1)
  65                 return (NULL);
  66         if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
  67                 errno = ENOTDIR;
  68                 close(fd);
  69                 return (NULL);
  70         }
  71         if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
  72             (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
  73                 close(fd);
  74                 return (NULL);
  75         }
  76
  77         /*
  78          * Determine whether this directory is the top of a union stack.
  79          * (Never is on a ramdisk)
  80          */
  81         {
  82                 dirp->dd_len = DIRBLKSIZ;
  83                 dirp->dd_buf = malloc((size_t)dirp->dd_len);
  84                 if (dirp->dd_buf == NULL) {
  85                         free(dirp);
  86                         close (fd);
  87                         return (NULL);
  88                 }
  89                 dirp->dd_seek = 0;
  90         }
  91
  92         dirp->dd_loc = 0;
  93         dirp->dd_fd = fd;
  94         dirp->dd_flags = DTF_HIDEW;
  95
  96         /*
  97          * Set up seek point for rewinddir.
  98          */
  99         dirp->dd_rewind = telldir(dirp);
 100
 101         return (dirp);
 102 }