xref: /freebsd/usr.bin/dirname/dirname.c (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
1 /*-
2  * Copyright (c) 1991, 1993, 1994
3  *	The Regents of the University of California.  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 static char copyright[] =
36 "@(#) Copyright (c) 1991, 1993, 1994\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 static char sccsid[] = "@(#)dirname.c	8.3 (Berkeley) 4/2/94";
42 #endif /* not lint */
43 
44 #include <stdio.h>
45 #include <stdlib.h>
46 
47 void usage __P((void));
48 
49 int
50 main(argc, argv)
51 	int argc;
52 	char **argv;
53 {
54 	char *p;
55 	int ch;
56 
57 	while ((ch = getopt(argc, argv, "")) != EOF)
58 		switch(ch) {
59 		case '?':
60 		default:
61 			usage();
62 		}
63 	argc -= optind;
64 	argv += optind;
65 
66 	if (argc != 1)
67 		usage();
68 
69 	/*
70 	 * (1) If string is //, skip steps (2) through (5).
71 	 * (2) If string consists entirely of slash characters, string
72 	 *     shall be set to a single slash character.  In this case,
73 	 *     skip steps (3) through (8).
74 	 */
75 	for (p = *argv;; ++p) {
76 		if (!*p) {
77 			if (p > *argv)
78 				(void)printf("/\n");
79 			else
80 				(void)printf(".\n");
81 			exit(0);
82 		}
83 		if (*p != '/')
84 			break;
85 	}
86 
87 	/*
88 	 * (3) If there are any trailing slash characters in string, they
89 	 *     shall be removed.
90 	 */
91 	for (; *p; ++p);
92 	while (*--p == '/')
93 		continue;
94 	*++p = '\0';
95 
96 	/*
97 	 * (4) If there are no slash characters remaining in string,
98 	 *     string shall be set to a single period character.  In this
99 	 *     case skip steps (5) through (8).
100 	 *
101 	 * (5) If there are any trailing nonslash characters in string,
102 	 *     they shall be removed.
103 	 */
104 	while (--p >= *argv)
105 		if (*p == '/')
106 			break;
107 	++p;
108 	if (p == *argv) {
109 		(void)printf(".\n");
110 		exit(0);
111 	}
112 
113 	/*
114 	 * (6) If the remaining string is //, it is implementation defined
115 	 *     whether steps (7) and (8) are skipped or processed.
116 	 *
117 	 * This case has already been handled, as part of steps (1) and (2).
118 	 */
119 
120 	/*
121 	 * (7) If there are any trailing slash characters in string, they
122 	 *     shall be removed.
123 	 */
124 	while (--p >= *argv)
125 		if (*p != '/')
126 			break;
127 	++p;
128 
129 	/*
130 	 * (8) If the remaining string is empty, string shall be set to
131 	 *     a single slash character.
132 	 */
133 	*p = '\0';
134 	(void)printf("%s\n", p == *argv ? "/" : *argv);
135 	exit(0);
136 }
137 
138 void
139 usage()
140 {
141 
142 	(void)fprintf(stderr, "usage: dirname path\n");
143 	exit(1);
144 }
145