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dirname.c revision 1.13 
      1 /*	$NetBSD: dirname.c,v 1.13 2014/07/16 10:52:26 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1997, 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Klaus Klein and Jason R. Thorpe.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: dirname.c,v 1.13 2014/07/16 10:52:26 christos Exp $");
     35 #endif /* !LIBC_SCCS && !lint */
     36 
     37 #include "namespace.h"
     38 #include <sys/param.h>
     39 #include <libgen.h>
     40 #include <limits.h>
     41 #include <string.h>
     42 
     43 #ifdef __weak_alias
     44 __weak_alias(dirname,_dirname)
     45 #endif
     46 
     47 static size_t
     48 xdirname_r(const char *path, char *buf, size_t buflen)
     49 {
     50 	const char *endp;
     51 	size_t len;
     52 
     53 	/*
     54 	 * If `path' is a null pointer or points to an empty string,
     55 	 * return a pointer to the string ".".
     56 	 */
     57 	if (path == NULL || *path == '\0') {
     58 		path = ".";
     59 		len = 1;
     60 		goto out;
     61 	}
     62 
     63 	/* Strip trailing slashes, if any. */
     64 	endp = path + strlen(path) - 1;
     65 	while (endp != path && *endp == '/')
     66 		endp--;
     67 
     68 	/* Find the start of the dir */
     69 	while (endp > path && *endp != '/')
     70 		endp--;
     71 
     72 	if (endp == path) {
     73 		path = *endp == '/' ? "/" : ".";
     74 		len = 1;
     75 		goto out;
     76 	}
     77 
     78 	do
     79 		endp--;
     80 	while (endp > path && *endp == '/');
     81 
     82 	len = endp - path + 1;
     83 out:
     84 	if (buf != NULL && buflen != 0) {
     85 		buflen = MIN(len, buflen - 1);
     86 		memcpy(buf, path, buflen);
     87 		buf[buflen] = '\0';
     88 	}
     89 	return len;
     90 }
     91 
     92 #if !HAVE_DIRNAME
     93 char *
     94 dirname(char *path)
     95 {
     96 	static char result[PATH_MAX];
     97 	(void)xdirname_r(path, result, sizeof(result));
     98 	return result;
     99 }
    100 #endif
    101