xref: /freebsd/usr.bin/dirname/dirname.c (revision 1c8af8787354e20c2b38cab5801698133ff8b403)
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	8.4 (Berkeley) 5/4/95";
42 #endif /* not lint */
43 
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <unistd.h>
47 
48 void usage __P((void));
49 
50 int
51 main(argc, argv)
52 	int argc;
53 	char **argv;
54 {
55 	char *p;
56 	int ch;
57 
58 	while ((ch = getopt(argc, argv, "")) != -1)
59 		switch(ch) {
60 		case '?':
61 		default:
62 			usage();
63 		}
64 	argc -= optind;
65 	argv += optind;
66 
67 	if (argc != 1)
68 		usage();
69 
70 	/*
71 	 * (1) If string is //, skip steps (2) through (5).
72 	 * (2) If string consists entirely of slash characters, string
73 	 *     shall be set to a single slash character.  In this case,
74 	 *     skip steps (3) through (8).
75 	 */
76 	for (p = *argv;; ++p) {
77 		if (!*p) {
78 			if (p > *argv)
79 				(void)printf("/\n");
80 			else
81 				(void)printf(".\n");
82 			exit(0);
83 		}
84 		if (*p != '/')
85 			break;
86 	}
87 
88 	/*
89 	 * (3) If there are any trailing slash characters in string, they
90 	 *     shall be removed.
91 	 */
92 	for (; *p; ++p);
93 	while (*--p == '/')
94 		continue;
95 	*++p = '\0';
96 
97 	/*
98 	 * (4) If there are no slash characters remaining in string,
99 	 *     string shall be set to a single period character.  In this
100 	 *     case skip steps (5) through (8).
101 	 *
102 	 * (5) If there are any trailing nonslash characters in string,
103 	 *     they shall be removed.
104 	 */
105 	while (--p >= *argv)
106 		if (*p == '/')
107 			break;
108 	++p;
109 	if (p == *argv) {
110 		(void)printf(".\n");
111 		exit(0);
112 	}
113 
114 	/*
115 	 * (6) If the remaining string is //, it is implementation defined
116 	 *     whether steps (7) and (8) are skipped or processed.
117 	 *
118 	 * This case has already been handled, as part of steps (1) and (2).
119 	 */
120 
121 	/*
122 	 * (7) If there are any trailing slash characters in string, they
123 	 *     shall be removed.
124 	 */
125 	while (--p >= *argv)
126 		if (*p != '/')
127 			break;
128 	++p;
129 
130 	/*
131 	 * (8) If the remaining string is empty, string shall be set to
132 	 *     a single slash character.
133 	 */
134 	*p = '\0';
135 	(void)printf("%s\n", p == *argv ? "/" : *argv);
136 	exit(0);
137 }
138 
139 void
140 usage()
141 {
142 
143 	(void)fprintf(stderr, "usage: dirname path\n");
144 	exit(1);
145 }
146