dirname.c revision 108152 
1/*
2 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
19 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#if 0
29#ifndef lint
30static char rcsid[] = "$OpenBSD: dirname.c,v 1.4 1999/05/30 17:10:30 espie Exp $";
31#endif /* not lint */
32#endif
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/gen/dirname.c 108152 2002-12-21 07:12:35Z bbraun $");
35
36#include <errno.h>
37#include <libgen.h>
38#include <string.h>
39#include <sys/param.h>
40
41char *
42dirname(path)
43	const char *path;
44{
45	static char *bname = NULL;
46	const char *endp;
47
48	if (bname == NULL) {
49		bname = (char *)malloc(MAXPATHLEN);
50		if (bname == NULL)
51			return(NULL);
52	}
53
54	/* Empty or NULL string gets treated as "." */
55	if (path == NULL || *path == '\0') {
56		(void)strcpy(bname, ".");
57		return(bname);
58	}
59
60	/* Strip trailing slashes */
61	endp = path + strlen(path) - 1;
62	while (endp > path && *endp == '/')
63		endp--;
64
65	/* Find the start of the dir */
66	while (endp > path && *endp != '/')
67		endp--;
68
69	/* Either the dir is "/" or there are no slashes */
70	if (endp == path) {
71		(void)strcpy(bname, *endp == '/' ? "/" : ".");
72		return(bname);
73	} else {
74		do {
75			endp--;
76		} while (endp > path && *endp == '/');
77	}
78
79	if (endp - path + 2 > MAXPATHLEN) {
80		errno = ENAMETOOLONG;
81		return(NULL);
82	}
83	(void)strncpy(bname, path, endp - path + 1);
84	bname[endp - path + 1] = '\0';
85	return(bname);
86}
87