lib/libc/gen/opendir.c

   1 /*      $NetBSD: opendir.c,v 1.39 2014/11/26 16:48:43 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 1.39 2014/11/26 16:48:43 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         DIR *dirp;
  79         int fd;
  80
  81         if ((fd = open(name, O_RDONLY|O_DIRECTORY|O_NONBLOCK|O_CLOEXEC)) == -1)
  82                 return NULL;
  83
  84         dirp = __opendir_common(fd, name, flags);
  85         if (dirp == NULL) {
  86                 int serrno = errno;
  87                 (void)close(fd);
  88                 errno = serrno;
  89         }
  90         return dirp;
  91 }
  92
  93 #ifndef __LIBC12_SOURCE__
  94 DIR *
  95 _fdopendir(int fd)
  96 {
  97         struct stat sb;
  98
  99         if (fstat(fd, &sb) == -1)
 100                 return NULL;
 101
 102         if (!S_ISDIR(sb.st_mode)) {
 103                 errno = ENOTDIR;
 104                 return NULL;
 105         }
 106
 107         /* This is optional according to POSIX, but a good measure */
 108         if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
 109                 return NULL;
 110
 111         return __opendir_common(fd, NULL, DTF_HIDEW|DTF_NODUP);
 112 }
 113 #endif
 114
 115 static DIR *
 116 __opendir_common(int fd, const char *name, int flags)
 117 {
 118         DIR *dirp;
 119         int serrno;
 120 #if !defined(__minix)
 121         struct statvfs sfb;
 122 #else
 123         struct stat sb;
 124 #endif /* !defined(__minix) */
 125         int error;
 126
 127 #if defined(__minix)
 128         dirp = NULL; /* LSC: Make sure the pointer is initialized */
 129         if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
 130                 errno = ENOTDIR;
 131                 goto error;
 132         }
 133 #endif /* defined(__minix) */
 134
 135         if ((dirp = malloc(sizeof(*dirp))) == NULL)
 136                 goto error;
 137         dirp->dd_buf = NULL;
 138         dirp->dd_internal = NULL;
 139 #ifdef _REENTRANT
 140         if (__isthreaded) {
 141                 if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
 142                         goto error;
 143                 mutex_init((mutex_t *)dirp->dd_lock, NULL);
 144         }
 145 #endif
 146
 147         /*
 148          * Tweak flags for the underlying filesystem.
 149          */
 150
 151 #if defined(__minix)
 152         /* MOUNT_UNION and MOUNT_NFS not supported */
 153         flags &= ~DTF_NODUP;
 154 #else
 155         if (fstatvfs1(fd, &sfb, ST_NOWAIT) < 0)
 156                 goto error;
 157         if ((flags & DTF_NODUP) != 0) {
 158                 if (!strncmp(sfb.f_fstypename, MOUNT_UNION,
 159                     sizeof(sfb.f_fstypename)) ||
 160                     (sfb.f_flag & MNT_UNION) != 0) {
 161                         flags |= __DTF_READALL;
 162                 } else {
 163                         flags &= ~DTF_NODUP;
 164                 }
 165         }
 166         if (!strncmp(sfb.f_fstypename, MOUNT_NFS, sizeof(sfb.f_fstypename))) {
 167                 flags |= __DTF_READALL | __DTF_RETRY_ON_BADCOOKIE;
 168         }
 169 #endif /* !defined(__minix) */
 170
 171         dirp->dd_flags = flags;
 172         error = _initdir(dirp, fd, name);
 173         if (error) {
 174                 errno = error;
 175                 goto error;
 176         }
 177
 178         return (dirp);
 179 error:
 180         serrno = errno;
 181         if (dirp != NULL) {
 182 #ifdef _REENTRANT
 183                 if (__isthreaded) {
 184                         mutex_destroy((mutex_t *)dirp->dd_lock);
 185                         free(dirp->dd_lock);
 186                 }
 187 #endif
 188                 free(dirp->dd_buf);
 189         }
 190         free(dirp);
 191         errno = serrno;
 192         return NULL;
 193 }