1/*	$OpenBSD: basename.c,v 1.17 2020/10/20 19:30:14 naddy Exp $	*/
2
3/*
4 * Copyright (c) 1997, 2004 Todd C. Miller <millert@openbsd.org>
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 <errno.h>
20#include <libgen.h>
21#include <limits.h>
22#include <string.h>
23
24char *
25basename(char *path)
26{
27	static char bname[PATH_MAX];
28	size_t len;
29	const char *endp, *startp;
30
31	/* Empty or NULL string gets treated as "." */
32	if (path == NULL || *path == '\0') {
33		bname[0] = '.';
34		bname[1] = '\0';
35		return (bname);
36	}
37
38	/* Strip any trailing slashes */
39	endp = path + strlen(path) - 1;
40	while (endp > path && *endp == '/')
41		endp--;
42
43	/* All slashes becomes "/" */
44	if (endp == path && *endp == '/') {
45		bname[0] = '/';
46		bname[1] = '\0';
47		return (bname);
48	}
49
50	/* Find the start of the base */
51	startp = endp;
52	while (startp > path && *(startp - 1) != '/')
53		startp--;
54
55	len = endp - startp + 1;
56	if (len >= sizeof(bname)) {
57		errno = ENAMETOOLONG;
58		return (NULL);
59	}
60	memcpy(bname, startp, len);
61	bname[len] = '\0';
62	return (bname);
63}
64