1 /*-
2 * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 #include <libgen.h>
27 #include <string.h>
28
29 char *
dirname(char * path)30 (dirname)(char *path)
31 {
32 char *end;
33
34 /*
35 * If path is a null pointer or points to an empty string,
36 * dirname() shall return a pointer to the string ".".
37 */
38 if (path == NULL || *path == '\0')
39 return (__DECONST(char *, "."));
40
41 /* Find end of last pathname component. */
42 end = path + strlen(path);
43 while (end > path + 1 && *(end - 1) == '/')
44 --end;
45
46 /* Strip off the last pathname component. */
47 while (end > path && *(end - 1) != '/')
48 --end;
49
50 /*
51 * If path does not contain a '/', then dirname() shall return a
52 * pointer to the string ".".
53 */
54 if (end == path) {
55 path[0] = '.';
56 path[1] = '\0';
57 return (path);
58 }
59
60 /*
61 * Remove trailing slashes from the resulting directory name. Ensure
62 * that at least one character remains.
63 */
64 while (end > path + 1 && *(end - 1) == '/')
65 --end;
66
67 /* Null terminate directory name and return it. */
68 *end = '\0';
69 return (path);
70 }
71