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
24 char *
basename(char * path)25 basename(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