1/* $NetBSD: pwd.c,v 1.21 2008/07/20 00:52:40 lukem Exp $ */
2
3/*
4 * Copyright (c) 1991, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#ifndef lint
34__COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\
35 The Regents of the University of California.  All rights reserved.");
36#endif /* not lint */
37
38#ifndef lint
39#if 0
40static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
41#else
42__RCSID("$NetBSD: pwd.c,v 1.21 2008/07/20 00:52:40 lukem Exp $");
43#endif
44#endif /* not lint */
45
46#include <sys/param.h>
47#include <sys/stat.h>
48#include <sys/types.h>
49
50#include <err.h>
51#include <errno.h>
52#include <locale.h>
53#include <stdio.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57
58static char *getcwd_logical(void);
59__dead static void usage(void);
60
61/*
62 * Note that EEE Std 1003.1, 2003 requires that the default be -L.
63 * This is inconsistent with the historic behaviour of everything
64 * except the ksh builtin.
65 * To avoid breaking scripts the default has been kept as -P.
66 * (Some scripts run /bin/pwd in order to get 'pwd -P'.)
67 */
68
69int
70main(int argc, char *argv[])
71{
72	int ch, lFlag;
73	const char *p;
74
75	setprogname(argv[0]);
76	(void)setlocale(LC_ALL, "");
77
78	lFlag = 0;
79	while ((ch = getopt(argc, argv, "LP")) != -1) {
80		switch (ch) {
81		case 'L':
82			lFlag = 1;
83			break;
84		case 'P':
85			lFlag = 0;
86			break;
87		case '?':
88		default:
89			usage();
90		}
91	}
92	argc -= optind;
93	argv += optind;
94
95	if (argc != 0)
96		usage();
97
98	if (lFlag)
99		p = getcwd_logical();
100	else
101		p = NULL;
102	if (p == NULL)
103		p = getcwd(NULL, 0);
104
105	if (p == NULL)
106		err(EXIT_FAILURE, NULL);
107
108	(void)printf("%s\n", p);
109
110	exit(EXIT_SUCCESS);
111	/* NOTREACHED */
112}
113
114static char *
115getcwd_logical(void)
116{
117	char *pwd;
118	struct stat s_pwd, s_dot;
119
120	/* Check $PWD -- if it's right, it's fast. */
121	pwd = getenv("PWD");
122	if (pwd == NULL)
123		return NULL;
124	if (pwd[0] != '/')
125		return NULL;
126	if (strstr(pwd, "/./") != NULL)
127		return NULL;
128	if (strstr(pwd, "/../") != NULL)
129		return NULL;
130	if (stat(pwd, &s_pwd) == -1 || stat(".", &s_dot) == -1)
131		return NULL;
132	if (s_pwd.st_dev != s_dot.st_dev || s_pwd.st_ino != s_dot.st_ino)
133		return NULL;
134	return pwd;
135}
136
137static void
138usage(void)
139{
140	(void)fprintf(stderr, "usage: %s [-LP]\n", getprogname());
141	exit(EXIT_FAILURE);
142	/* NOTREACHED */
143}
144