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 #include <errno.h>
26 #include <libgen.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <sys/param.h>
30
31 char *
dirname(char * path)32 dirname(char *path)
33 {
34 char *end;
35
36 /*
37 * If path is a null pointer or points to an empty string,
38 * dirname() shall return a pointer to the string ".".
39 */
40 if (path == NULL || *path == '\0')
41 return (__DECONST(char *, "."));
42
43 /* Find end of last pathname component. */
44 end = path + strlen(path);
45 while (end > path + 1 && end[-1] == '/')
46 --end;
47
48 /* Strip off the last pathname component. */
49 while (end > path && end[-1] != '/')
50 --end;
51
52 /*
53 * If path does not contain a '/', then dirname() shall return a
54 * pointer to the string ".".
55 */
56 if (end == path) {
57 path[0] = '.';
58 path[1] = '\0';
59 return (path);
60 }
61
62 /*
63 * Remove trailing slashes from the resulting directory name. Ensure
64 * that at least one character remains.
65 */
66 while (end > path + 1 && end[-1] == '/')
67 --end;
68
69 /* Null terminate directory name and return it. */
70 *end = '\0';
71 return (path);
72 }
73