xref: /freebsd/lib/libc/gen/dirname.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
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
30 static 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$");
35 
36 #include <errno.h>
37 #include <libgen.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <sys/param.h>
41 
42 char *
43 dirname(path)
44 	const char *path;
45 {
46 	static char *bname = NULL;
47 	const char *endp;
48 
49 	if (bname == NULL) {
50 		bname = (char *)malloc(MAXPATHLEN);
51 		if (bname == NULL)
52 			return(NULL);
53 	}
54 
55 	/* Empty or NULL string gets treated as "." */
56 	if (path == NULL || *path == '\0') {
57 		(void)strcpy(bname, ".");
58 		return(bname);
59 	}
60 
61 	/* Strip trailing slashes */
62 	endp = path + strlen(path) - 1;
63 	while (endp > path && *endp == '/')
64 		endp--;
65 
66 	/* Find the start of the dir */
67 	while (endp > path && *endp != '/')
68 		endp--;
69 
70 	/* Either the dir is "/" or there are no slashes */
71 	if (endp == path) {
72 		(void)strcpy(bname, *endp == '/' ? "/" : ".");
73 		return(bname);
74 	} else {
75 		do {
76 			endp--;
77 		} while (endp > path && *endp == '/');
78 	}
79 
80 	if (endp - path + 2 > MAXPATHLEN) {
81 		errno = ENAMETOOLONG;
82 		return(NULL);
83 	}
84 	(void)strncpy(bname, path, endp - path + 1);
85 	bname[endp - path + 1] = '\0';
86 	return(bname);
87 }
88