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opendir.c revision 1.37 
      1 /*	$NetBSD: opendir.c,v 1.37 2010/09/26 02:26:59 yamt 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 1.37 2010/09/26 02:26:59 yamt 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)) == -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 
     90 	return __opendir_common(fd, NULL, DTF_HIDEW|DTF_NODUP);
     91 }
     92 #endif
     93 
     94 static DIR *
     95 __opendir_common(int fd, const char *name, int flags)
     96 {
     97 	DIR *dirp = NULL;
     98 	int serrno;
     99 	struct stat sb;
    100 	struct statvfs sfb;
    101 	int error;
    102 
    103 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)
    104 		goto error;
    105 	if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
    106 		errno = ENOTDIR;
    107 		goto error;
    108 	}
    109 	if ((dirp = (DIR *)malloc(sizeof(DIR))) == NULL)
    110 		goto error;
    111 	dirp->dd_buf = NULL;
    112 	dirp->dd_internal = NULL;
    113 #ifdef _REENTRANT
    114 	if (__isthreaded) {
    115 		if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
    116 			goto error;
    117 		mutex_init((mutex_t *)dirp->dd_lock, NULL);
    118 	}
    119 #endif
    120 
    121 	/*
    122 	 * Tweak flags for the underlying filesystem.
    123 	 */
    124 
    125 	if (fstatvfs1(fd, &sfb, ST_NOWAIT) < 0)
    126 		goto error;
    127 	if ((flags & DTF_NODUP) != 0) {
    128 		if (!strncmp(sfb.f_fstypename, MOUNT_UNION,
    129 		    sizeof(sfb.f_fstypename)) ||
    130 		    (sfb.f_flag & MNT_UNION) != 0) {
    131 			flags |= __DTF_READALL;
    132 		} else {
    133 			flags &= ~DTF_NODUP;
    134 		}
    135 	}
    136 	if (!strncmp(sfb.f_fstypename, MOUNT_NFS, sizeof(sfb.f_fstypename))) {
    137 		flags |= __DTF_READALL | __DTF_RETRY_ON_BADCOOKIE;
    138 	}
    139 
    140 	dirp->dd_flags = flags;
    141 	error = _initdir(dirp, fd, name);
    142 	if (error) {
    143 		errno = error;
    144 		goto error;
    145 	}
    146 
    147 	return (dirp);
    148 error:
    149 	serrno = errno;
    150 	if (dirp != NULL) {
    151 #ifdef _REENTRANT
    152 		if (__isthreaded) {
    153 			mutex_destroy((mutex_t *)dirp->dd_lock);
    154 			free(dirp->dd_lock);
    155 		}
    156 #endif
    157 		free(dirp->dd_buf);
    158 	}
    159 	free(dirp);
    160 	if (fd != -1)
    161 		(void)close(fd);
    162 	errno = serrno;
    163 	return NULL;
    164 }
    165