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      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 	struct statvfs sfb;
    121 	int error;
    122 
    123 	if ((dirp = malloc(sizeof(*dirp))) == NULL)
    124 		goto error;
    125 	dirp->dd_buf = NULL;
    126 	dirp->dd_internal = NULL;
    127 #ifdef _REENTRANT
    128 	if (__isthreaded) {
    129 		if ((dirp->dd_lock = malloc(sizeof(mutex_t))) == NULL)
    130 			goto error;
    131 		mutex_init((mutex_t *)dirp->dd_lock, NULL);
    132 	}
    133 #endif
    134 
    135 	/*
    136 	 * Tweak flags for the underlying filesystem.
    137 	 */
    138 
    139 	if (fstatvfs1(fd, &sfb, ST_NOWAIT) < 0)
    140 		goto error;
    141 	if ((flags & DTF_NODUP) != 0) {
    142 		if (!strncmp(sfb.f_fstypename, MOUNT_UNION,
    143 		    sizeof(sfb.f_fstypename)) ||
    144 		    (sfb.f_flag & MNT_UNION) != 0) {
    145 			flags |= __DTF_READALL;
    146 		} else {
    147 			flags &= ~DTF_NODUP;
    148 		}
    149 	}
    150 	if (!strncmp(sfb.f_fstypename, MOUNT_NFS, sizeof(sfb.f_fstypename))) {
    151 		flags |= __DTF_READALL | __DTF_RETRY_ON_BADCOOKIE;
    152 	}
    153 
    154 	dirp->dd_flags = flags;
    155 	error = _initdir(dirp, fd, name);
    156 	if (error) {
    157 		errno = error;
    158 		goto error;
    159 	}
    160 
    161 	return (dirp);
    162 error:
    163 	serrno = errno;
    164 	if (dirp != NULL) {
    165 #ifdef _REENTRANT
    166 		if (__isthreaded) {
    167 			mutex_destroy((mutex_t *)dirp->dd_lock);
    168 			free(dirp->dd_lock);
    169 		}
    170 #endif
    171 		free(dirp->dd_buf);
    172 	}
    173 	free(dirp);
    174 	errno = serrno;
    175 	return NULL;
    176 }
    177