lib/libc/gen/opendir.c

   1 /*      $NetBSD: opendir.c,v 1.38 2011/10/15 23:00:01 christos 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[] = "@(#)opendir.c   8.7 (Berkeley) 12/10/94";
  36 #else
  37 __RCSID("$NetBSD: opendir.c,v 1.38 2011/10/15 23:00:01 christos Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include "reentrant.h"
  43 #include "extern.h"
  44
  45 #include <sys/param.h>
  46 #include <sys/mount.h>
  47 #include <sys/stat.h>
  48
  49 #include <assert.h>
  50 #include <dirent.h>
  51 #include <errno.h>
  52 #include <fcntl.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56
  57 #include "dirent_private.h"
  58
  59 static DIR      *__opendir_common(int, const char *, int);
  60
  61 __weak_alias(fdopendir,_fdopendir)
  62
  63 /*
  64  * Open a directory.
  65  */
  66 DIR *
  67 opendir(const char *name)
  68 {
  69
  70         _DIAGASSERT(name != NULL);
  71
  72         return (__opendir2(name, DTF_HIDEW|DTF_NODUP));
  73 }
  74
  75 DIR *
  76 __opendir2(const char *name, int flags)
  77 {
  78         int fd;
  79
  80         if ((fd = open(name, O_RDONLY | O_NONBLOCK | O_CLOEXEC)) == -1)
  81                 return NULL;
  82         return __opendir_common(fd, name, flags);
  83 }
  84
  85 #ifndef __LIBC12_SOURCE__
  86 DIR *
  87 _fdopendir(int fd)
  88 {
  89         if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
  90                 return NULL;
  91
  92         return __opendir_common(fd, NULL, DTF_HIDEW|DTF_NODUP);
  93 }
  94 #endif
  95
  96 static DIR *
  97 __opendir_common(int fd, const char *name, int flags)
  98 {
  99         DIR *dirp = NULL;
 100         int serrno;
 101         struct stat sb;
 102 #if !defined(__minix)
 103         struct statvfs sfb;
 104 #endif /* !defined(__minix) */
 105         int error;
 106
 107         if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
 108                 errno = ENOTDIR;
 109                 goto error;
 110         }
 111         if ((dirp = malloc(sizeof(*dirp))) == NULL)
 112                 goto error;
 113         dirp->dd_buf = NULL;
 114         dirp->dd_internal = NULL;
 115 #ifdef _REENTRANT
 116         if (__isthreaded) {
 117                 if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
 118                         goto error;
 119                 mutex_init((mutex_t *)dirp->dd_lock, NULL);
 120         }
 121 #endif
 122
 123         /*
 124          * Tweak flags for the underlying filesystem.
 125          */
 126
 127 #if defined(__minix)
 128         /* MOUNT_UNION and MOUNT_NFS not supported */
 129         flags &= ~DTF_NODUP;
 130 #else
 131         if (fstatvfs1(fd, &sfb, ST_NOWAIT) < 0)
 132                 goto error;
 133         if ((flags & DTF_NODUP) != 0) {
 134                 if (!strncmp(sfb.f_fstypename, MOUNT_UNION,
 135                     sizeof(sfb.f_fstypename)) ||
 136                     (sfb.f_flag & MNT_UNION) != 0) {
 137                         flags |= __DTF_READALL;
 138                 } else {
 139                         flags &= ~DTF_NODUP;
 140                 }
 141         }
 142         if (!strncmp(sfb.f_fstypename, MOUNT_NFS, sizeof(sfb.f_fstypename))) {
 143                 flags |= __DTF_READALL | __DTF_RETRY_ON_BADCOOKIE;
 144         }
 145 #endif /* !defined(__minix) */
 146
 147         dirp->dd_flags = flags;
 148         error = _initdir(dirp, fd, name);
 149         if (error) {
 150                 errno = error;
 151                 goto error;
 152         }
 153
 154         return (dirp);
 155 error:
 156         serrno = errno;
 157         if (dirp != NULL) {
 158 #ifdef _REENTRANT
 159                 if (__isthreaded) {
 160                         mutex_destroy((mutex_t *)dirp->dd_lock);
 161                         free(dirp->dd_lock);
 162                 }
 163 #endif
 164                 free(dirp->dd_buf);
 165         }
 166         free(dirp);
 167         if (fd != -1)
 168                 (void)close(fd);
 169         errno = serrno;
 170         return NULL;
 171 }