xref: /netbsd-src/usr.bin/dirname/dirname.c (revision ce63d6c20fc4ec8ddc95c84bb229e3c4ecf82b69)
1 /*-
2  * Copyright (c) 1991 The Regents of the University of California.
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. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 char copyright[] =
36 "@(#) Copyright (c) 1991 The Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 static char sccsid[] = "@(#)dirname.c	5.6 (Berkeley) 3/9/91";
42 #endif /* not lint */
43 
44 #include <stdio.h>
45 #include <stdlib.h>
46 
47 main(argc, argv)
48 	int argc;
49 	char **argv;
50 {
51 	extern int optind;
52 	register char *p;
53 	int ch;
54 
55 	while ((ch = getopt(argc, argv, "")) != EOF)
56 		switch(ch) {
57 		case '?':
58 		default:
59 			usage();
60 		}
61 	argc -= optind;
62 	argv += optind;
63 
64 	if (argc != 1)
65 		usage();
66 
67 	/*
68 	 * (1) If string is //, skip steps (2) through (5).
69 	 * (2) If string consists entirely of slash characters, string
70 	 *     shall be set to a single slash character.  In this case,
71 	 *     skip steps (3) through (8).
72 	 */
73 	for (p = *argv;; ++p) {
74 		if (!*p) {
75 			if (p > *argv)
76 				(void)printf("/\n");
77 			else
78 				(void)printf(".\n");
79 			exit(0);
80 		}
81 		if (*p != '/')
82 			break;
83 	}
84 
85 	/*
86 	 * (3) If there are any trailing slash characters in string, they
87 	 *     shall be removed.
88 	 */
89 	for (; *p; ++p);
90 	while (*--p == '/');
91 	*++p = '\0';
92 
93 	/*
94 	 * (4) If there are no slash characters remaining in string,
95 	 *     string shall be set to a single period character.  In this
96 	 *     case skip steps (5) through (8).
97 	 *
98 	 * (5) If there are any trailing nonslash characters in string,
99 	 *     they shall be removed.
100 	 */
101 	while (--p >= *argv)
102 		if (*p == '/')
103 			break;
104 	++p;
105 	if (p == *argv) {
106 		(void)printf(".\n");
107 		exit(0);
108 	}
109 
110 	/*
111 	 * (6) If the remaining string is //, it is implementation defined
112 	 *     whether steps (7) and (8) are skipped or processed.
113 	 *
114 	 * This case has already been handled, as part of steps (1) and (2).
115 	 */
116 
117 	/*
118 	 * (7) If there are any trailing slash characters in string, they
119 	 *     shall be removed.
120 	 */
121 	while (--p >= *argv)
122 		if (*p != '/')
123 			break;
124 	++p;
125 
126 	/*
127 	 * (8) If the remaining string is empty, string shall be set to
128 	 *     a single slash character.
129 	 */
130 	*p = '\0';
131 	(void)printf("%s\n", p == *argv ? "/" : *argv);
132 	exit(0);
133 }
134 
135 usage()
136 {
137 	(void)fprintf(stderr, "usage: dirname path\n");
138 	exit(1);
139 }
140