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pwd.c revision 1.19.30.1 
      1 /* $NetBSD: pwd.c,v 1.19.30.1 2008/06/04 02:02:56 yamt 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\n\
     35 	The Regents of the University of California.  All rights reserved.\n");
     36 #endif /* not lint */
     37 
     38 #ifndef lint
     39 #if 0
     40 static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
     41 #else
     42 __RCSID("$NetBSD: pwd.c,v 1.19.30.1 2008/06/04 02:02:56 yamt 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 
     58 static char *getcwd_logical(void);
     59 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 
     69 int
     70 main(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 
    114 static char *
    115 getcwd_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 
    137 static void
    138 usage(void)
    139 {
    140 	(void)fprintf(stderr, "usage: %s [-LP]\n", getprogname());
    141 	exit(EXIT_FAILURE);
    142 	/* NOTREACHED */
    143 }
    144