xref: /openbsd-src/lib/libc/gen/basename.c (revision 62a742911104f98b9185b2c6b6007d9b1c36396c)
1 /*	$OpenBSD: basename.c,v 1.2 1998/06/21 22:13:39 millert Exp $	*/
2 
3 /*
4  * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #ifndef lint
31 static char rcsid[] = "$OpenBSD: basename.c,v 1.2 1998/06/21 22:13:39 millert Exp $";
32 #endif /* not lint */
33 
34 #include <errno.h>
35 #include <libgen.h>
36 #include <string.h>
37 #include <sys/param.h>
38 
39 char *
40 basename(path)
41 	char *path;
42 {
43 	static char bname[MAXPATHLEN];
44 	register char *endp, *startp;
45 
46 	/* Empty or NULL string gets treated as "." */
47 	if (path == NULL || *path == '\0') {
48 		(void)strcpy(bname, ".");
49 		return(bname);
50 	}
51 
52 	/* Strip trailing slashes */
53 	endp = path + strlen(path) - 1;
54 	while (endp > path && *endp == '/')
55 		endp--;
56 
57 	/* All slashes becomes "/" */
58 	if (endp == path && *endp == '/') {
59 		(void)strcpy(bname, "/");
60 		return(bname);
61 	}
62 
63 	/* Find the start of the base */
64 	startp = endp;
65 	while (startp > path && *(startp - 1) != '/')
66 		startp--;
67 
68 	if (endp - startp + 1 > sizeof(bname)) {
69 		errno = ENAMETOOLONG;
70 		return(NULL);
71 	}
72 	(void)strncpy(bname, startp, endp - startp + 1);
73 	bname[endp - startp + 1] = '\0';
74 	return(bname);
75 }
76