1/*	$OpenBSD: pwd.c,v 1.14 2015/10/09 01:37:06 deraadt Exp $	*/
2/*	$NetBSD: pwd.c,v 1.22 2011/08/29 14:51:19 joerg Exp $	*/
3
4/*
5 * Copyright (c) 1991, 1993, 1994
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/stat.h>
34
35#include <err.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <unistd.h>
39
40extern char *__progname;
41static char *getcwd_logical(void);
42__dead static void usage(void);
43
44int
45main(int argc, char *argv[])
46{
47	int ch, lFlag = 0;
48	const char *p;
49
50	if (pledge("stdio rpath", NULL) == -1)
51		err(1, "pledge");
52
53	while ((ch = getopt(argc, argv, "LP")) != -1) {
54		switch (ch) {
55		case 'L':
56			lFlag = 1;
57			break;
58		case 'P':
59			lFlag = 0;
60			break;
61		default:
62			usage();
63		}
64	}
65	argc -= optind;
66	argv += optind;
67
68	if (argc != 0)
69		usage();
70
71	if (lFlag)
72		p = getcwd_logical();
73	else
74		p = NULL;
75	if (p == NULL)
76		p = getcwd(NULL, 0);
77
78	if (p == NULL)
79		err(EXIT_FAILURE, NULL);
80
81	puts(p);
82
83	exit(EXIT_SUCCESS);
84}
85
86static char *
87getcwd_logical(void)
88{
89	char *pwd, *p;
90	struct stat s_pwd, s_dot;
91
92	/* Check $PWD -- if it's right, it's fast. */
93	pwd = getenv("PWD");
94	if (pwd == NULL)
95		return NULL;
96	if (pwd[0] != '/')
97		return NULL;
98
99	/* check for . or .. components, including trailing ones */
100	for (p = pwd; *p != '\0'; p++)
101		if (p[0] == '/' && p[1] == '.') {
102			if (p[2] == '.')
103				p++;
104			if (p[2] == '\0' || p[2] == '/')
105				return NULL;
106		}
107
108	if (stat(pwd, &s_pwd) == -1 || stat(".", &s_dot) == -1)
109		return NULL;
110	if (s_pwd.st_dev != s_dot.st_dev || s_pwd.st_ino != s_dot.st_ino)
111		return NULL;
112	return pwd;
113}
114
115static void
116usage(void)
117{
118	fprintf(stderr, "usage: %s [-LP]\n", __progname);
119	exit(EXIT_FAILURE);
120}
121