xref: /dragonfly/bin/pwd/pwd.c (revision 926deccb)
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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * @(#) Copyright (c) 1991, 1993, 1994 The Regents of the University of California.  All rights reserved.
30  * @(#)pwd.c	8.3 (Berkeley) 4/1/94
31  * $FreeBSD: src/bin/pwd/pwd.c,v 1.9.2.3 2002/06/17 11:04:22 tjr Exp $
32  * $DragonFly: src/bin/pwd/pwd.c,v 1.5 2005/03/05 21:58:20 liamfoy Exp $
33  */
34 
35 #include <sys/param.h>
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 
39 #include <err.h>
40 #include <errno.h>
41 #include <limits.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 
47 static char	*getcwd_logical(void);
48 static void	usage(void);
49 
50 int
51 main(int argc, char *argv[])
52 {
53 	int physical;
54 	int ch;
55 	char *p;
56 	char buf[PATH_MAX];
57 
58 	if (strcmp(getprogname(), "realpath") == 0) {
59 		if (argc != 2)
60 			usage();
61 		if ((p = realpath(argv[1], buf)) == NULL)
62 			err(1, "%s", argv[1]);
63 		printf("%s\n", p);
64 		exit(0);
65 	}
66 
67 	physical = 1;
68 	while ((ch = getopt(argc, argv, "LP")) != -1)
69 		switch (ch) {
70 		case 'L':
71 			physical = 0;
72 			break;
73 		case 'P':
74 			physical = 1;
75 			break;
76 		case '?':
77 		default:
78 			usage();
79 		}
80 	argc -= optind;
81 	argv += optind;
82 
83 	if (argc != 0)
84 		usage();
85 
86 	/*
87 	 * If we're trying to find the logical current directory and that
88 	 * fails, behave as if -P was specified.
89 	 */
90 	if ((!physical && (p = getcwd_logical()) != NULL) ||
91 	    (p = getcwd(NULL, 0)) != NULL)
92 		printf("%s\n", p);
93 	else
94 		err(1, ".");
95 
96 	exit(0);
97 }
98 
99 static void
100 usage(void)
101 {
102 	if (strcmp(getprogname(), "realpath") == 0)
103 		fprintf(stderr, "usage: realpath [path]\n");
104 	else
105 		fprintf(stderr, "usage: pwd [-LP]\n");
106   	exit(1);
107 }
108 
109 static char *
110 getcwd_logical(void)
111 {
112 	struct stat logic, phy;
113 	char *pwd;
114 
115 	/*
116 	 * Check that $PWD is an absolute logical pathname referring to
117 	 * the current working directory.
118 	 */
119 	if ((pwd = getenv("PWD")) != NULL && *pwd == '/') {
120 		if (stat(pwd, &logic) == -1 || stat(".", &phy) == -1)
121 			return (NULL);
122 		if (logic.st_dev == phy.st_dev && logic.st_ino == phy.st_ino)
123 			return (pwd);
124 	}
125 
126 	errno = ENOENT;
127 	return (NULL);
128 }
129