1/*	$OpenBSD: dirname.c,v 1.13 2005/08/08 08:05:33 espie Exp $	*/
2
3/*
4 * Copyright (c) 1997, 2004 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/cdefs.h>
20__FBSDID("$FreeBSD$");
21
22#include <errno.h>
23#include <libgen.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/param.h>
27
28char *
29dirname(const char *path)
30{
31	static char *dname = NULL;
32	size_t len;
33	const char *endp;
34
35	if (dname == NULL) {
36		dname = (char *)malloc(MAXPATHLEN);
37		if (dname == NULL)
38			return(NULL);
39	}
40
41	/* Empty or NULL string gets treated as "." */
42	if (path == NULL || *path == '\0') {
43		dname[0] = '.';
44		dname[1] = '\0';
45		return (dname);
46	}
47
48	/* Strip any trailing slashes */
49	endp = path + strlen(path) - 1;
50	while (endp > path && *endp == '/')
51		endp--;
52
53	/* Find the start of the dir */
54	while (endp > path && *endp != '/')
55		endp--;
56
57	/* Either the dir is "/" or there are no slashes */
58	if (endp == path) {
59		dname[0] = *endp == '/' ? '/' : '.';
60		dname[1] = '\0';
61		return (dname);
62	} else {
63		/* Move forward past the separating slashes */
64		do {
65			endp--;
66		} while (endp > path && *endp == '/');
67	}
68
69	len = endp - path + 1;
70	if (len >= MAXPATHLEN) {
71		errno = ENAMETOOLONG;
72		return (NULL);
73	}
74	memcpy(dname, path, len);
75	dname[len] = '\0';
76	return (dname);
77}
78