xref: /netbsd-src/lib/libc/gen/dirname.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: dirname.c,v 1.11 2009/11/24 13:34:20 tnozaki 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 1.11 2009/11/24 13:34:20 tnozaki Exp $");
35 #endif /* !LIBC_SCCS && !lint */
36 
37 #include "namespace.h"
38 #include <libgen.h>
39 #include <limits.h>
40 #include <string.h>
41 
42 #ifdef __weak_alias
43 __weak_alias(dirname,_dirname)
44 #endif
45 
46 #if !HAVE_DIRNAME
47 char *
48 dirname(char *path)
49 {
50 	static char result[PATH_MAX];
51 	const char *lastp;
52 	size_t len;
53 
54 	/*
55 	 * If `path' is a null pointer or points to an empty string,
56 	 * return a pointer to the string ".".
57 	 */
58 	if ((path == NULL) || (*path == '\0'))
59 		goto singledot;
60 
61 
62 	/* Strip trailing slashes, if any. */
63 	lastp = path + strlen(path) - 1;
64 	while (lastp != path && *lastp == '/')
65 		lastp--;
66 
67 	/* Terminate path at the last occurence of '/'. */
68 	do {
69 		if (*lastp == '/') {
70 			/* Strip trailing slashes, if any. */
71 			while (lastp != path && *lastp == '/')
72 				lastp--;
73 
74 			/* ...and copy the result into the result buffer. */
75 			len = (lastp - path) + 1 /* last char */;
76 			if (len > (PATH_MAX - 1))
77 				len = PATH_MAX - 1;
78 
79 			memcpy(result, path, len);
80 			result[len] = '\0';
81 
82 			return (result);
83 		}
84 	} while (--lastp >= path);
85 
86 	/* No /'s found, return a pointer to the string ".". */
87 singledot:
88 	result[0] = '.';
89 	result[1] = '\0';
90 
91 	return (result);
92 }
93 #endif
94