dirname.c revision 78936 
1/*	$OpenBSD: dirname.c,v 1.4 1999/05/30 17:10:30 espie Exp $	*/
2/*	$FreeBSD: head/lib/libc/gen/dirname.c 78936 2001-06-28 21:50:53Z dd $	*/
3
4/*
5 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
21 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
22 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
25 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
27 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
28 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef lint
32static char rcsid[] = "$OpenBSD: dirname.c,v 1.4 1999/05/30 17:10:30 espie Exp $";
33#endif /* not lint */
34
35#include <errno.h>
36#include <libgen.h>
37#include <string.h>
38#include <sys/param.h>
39
40char *
41dirname(path)
42	const char *path;
43{
44	static char bname[MAXPATHLEN];
45	register const char *endp;
46
47	/* Empty or NULL string gets treated as "." */
48	if (path == NULL || *path == '\0') {
49		(void)strcpy(bname, ".");
50		return(bname);
51	}
52
53	/* Strip trailing slashes */
54	endp = path + strlen(path) - 1;
55	while (endp > path && *endp == '/')
56		endp--;
57
58	/* Find the start of the dir */
59	while (endp > path && *endp != '/')
60		endp--;
61
62	/* Either the dir is "/" or there are no slashes */
63	if (endp == path) {
64		(void)strcpy(bname, *endp == '/' ? "/" : ".");
65		return(bname);
66	} else {
67		do {
68			endp--;
69		} while (endp > path && *endp == '/');
70	}
71
72	if (endp - path + 2 > sizeof(bname)) {
73		errno = ENAMETOOLONG;
74		return(NULL);
75	}
76	(void)strncpy(bname, path, endp - path + 1);
77	bname[endp - path + 1] = '\0';
78	return(bname);
79}
80