xref: /freebsd/bin/pwd/pwd.c (revision eacee0ff7ec955b32e09515246bd97b6edcd2b0f)
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 const 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 #if 0
42 static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <sys/param.h>
49 #include <sys/stat.h>
50 #include <sys/types.h>
51 
52 #include <err.h>
53 #include <errno.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <unistd.h>
57 
58 static char *getcwd_logical(void);
59 void usage(void);
60 
61 int
62 main(int argc, char *argv[])
63 {
64 	int Lflag, Pflag;
65 	int ch;
66 	char *p;
67 
68 	Lflag = Pflag = 0;
69 	while ((ch = getopt(argc, argv, "LP")) != -1)
70 		switch (ch) {
71 		case 'L':
72 			Lflag = 1;
73 			break;
74 		case 'P':
75 			Pflag = 1;
76 			break;
77 		case '?':
78 		default:
79 			usage();
80 		}
81 	argc -= optind;
82 	argv += optind;
83 
84 	if (argc != 0 || (Lflag && Pflag))
85 		usage();
86 
87 	p = Lflag ? getcwd_logical() : getcwd(NULL, 0);
88 	if (p == NULL)
89 		err(1, ".");
90 	(void)printf("%s\n", p);
91 
92 	exit(0);
93 }
94 
95 void
96 usage(void)
97 {
98 
99 	(void)fprintf(stderr, "usage: pwd [-L | -P]\n");
100   	exit(1);
101 }
102 
103 static char *
104 getcwd_logical(void)
105 {
106 	struct stat log, phy;
107 	char *pwd;
108 
109 	/*
110 	 * Check that $PWD is an absolute logical pathname referring to
111 	 * the current working directory.
112 	 */
113 	if ((pwd = getenv("PWD")) != NULL && *pwd == '/') {
114 		if (stat(pwd, &log) == -1 || stat(".", &phy) == -1)
115 			return (NULL);
116 		if (log.st_dev == phy.st_dev && log.st_ino == phy.st_ino)
117 			return (pwd);
118 	}
119 
120 	errno = ENOENT;
121 	return (NULL);
122 }
123