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opendir.c revision 1.1.2.2 
      1 /*	$NetBSD: opendir.c,v 1.1.2.2 1999/06/21 13:38:00 perry 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/param.h>
     37 #include <sys/mount.h>
     38 #include <sys/stat.h>
     39 
     40 #include <dirent.h>
     41 #include <errno.h>
     42 #include <fcntl.h>
     43 #include <stdlib.h>
     44 #include <string.h>
     45 #include <unistd.h>
     46 
     47 /*
     48  * Open a directory.
     49  */
     50 DIR *
     51 opendir(name)
     52 	const char *name;
     53 {
     54 	DIR *dirp;
     55 	int fd;
     56 	struct stat sb;
     57 
     58 	if ((fd = open(name, O_RDONLY | O_NONBLOCK)) == -1)
     59 		return (NULL);
     60 	if (fstat(fd, &sb) || !S_ISDIR(sb.st_mode)) {
     61 		errno = ENOTDIR;
     62 		close(fd);
     63 		return (NULL);
     64 	}
     65 	if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1 ||
     66 	    (dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
     67 		close(fd);
     68 		return (NULL);
     69 	}
     70 
     71 	/*
     72 	 * Determine whether this directory is the top of a union stack.
     73 	 * (Never is on a ramdisk)
     74 	 */
     75 	{
     76 		dirp->dd_len = DIRBLKSIZ;
     77 		dirp->dd_buf = malloc((size_t)dirp->dd_len);
     78 		if (dirp->dd_buf == NULL) {
     79 			free(dirp);
     80 			close (fd);
     81 			return (NULL);
     82 		}
     83 		dirp->dd_seek = 0;
     84 	}
     85 
     86 	dirp->dd_loc = 0;
     87 	dirp->dd_fd = fd;
     88 	dirp->dd_flags = DTF_HIDEW;
     89 
     90 	/*
     91 	 * Set up seek point for rewinddir.
     92 	 */
     93 	dirp->dd_rewind = telldir(dirp);
     94 
     95 	return (dirp);
     96 }
     97