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pwd.c revision 1.19 
      1 /* $NetBSD: pwd.c,v 1.19 2003/10/30 13:52:23 dsl 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 2003/10/30 13:52:23 dsl 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 <stdio.h>
     53 #include <stdlib.h>
     54 #include <string.h>
     55 #include <unistd.h>
     56 
     57 static char *getcwd_logical(void);
     58 static void usage(void);
     59 
     60 /*
     61  * Note that EEE Std 1003.1, 2003 requires that the default be -L.
     62  * This is inconsistent with the historic behaviour of everything
     63  * except the ksh builtin.
     64  * To avoid breaking scripts the default has been kept as -P.
     65  * (Some scripts run /bin/pwd in order to get 'pwd -P'.)
     66  */
     67 
     68 int
     69 main(int argc, char *argv[])
     70 {
     71 	int ch, lFlag;
     72 	const char *p;
     73 
     74 	setprogname(argv[0]);
     75 	lFlag = 0;
     76 	while ((ch = getopt(argc, argv, "LP")) != -1) {
     77 		switch (ch) {
     78 		case 'L':
     79 			lFlag = 1;
     80 			break;
     81 		case 'P':
     82 			lFlag = 0;
     83 			break;
     84 		case '?':
     85 		default:
     86 			usage();
     87 		}
     88 	}
     89 	argc -= optind;
     90 	argv += optind;
     91 
     92 	if (argc != 0)
     93 		usage();
     94 
     95 	if (lFlag)
     96 		p = getcwd_logical();
     97 	else
     98 		p = NULL;
     99 	if (p == NULL)
    100 		p = getcwd(NULL, 0);
    101 
    102 	if (p == NULL)
    103 		err(EXIT_FAILURE, NULL);
    104 
    105 	(void)printf("%s\n", p);
    106 
    107 	exit(EXIT_SUCCESS);
    108 	/* NOTREACHED */
    109 }
    110 
    111 static char *
    112 getcwd_logical(void)
    113 {
    114 	char *pwd;
    115 	struct stat s_pwd, s_dot;
    116 
    117 	/* Check $PWD -- if it's right, it's fast. */
    118 	pwd = getenv("PWD");
    119 	if (pwd == NULL)
    120 		return NULL;
    121 	if (pwd[0] != '/')
    122 		return NULL;
    123 	if (strstr(pwd, "/./") != NULL)
    124 		return NULL;
    125 	if (strstr(pwd, "/../") != NULL)
    126 		return NULL;
    127 	if (stat(pwd, &s_pwd) == -1 || stat(".", &s_dot) == -1)
    128 		return NULL;
    129 	if (s_pwd.st_dev != s_dot.st_dev || s_pwd.st_ino != s_dot.st_ino)
    130 		return NULL;
    131 	return pwd;
    132 }
    133 
    134 static void
    135 usage(void)
    136 {
    137 	(void)fprintf(stderr, "usage: %s [-LP]\n", getprogname());
    138 	exit(EXIT_FAILURE);
    139 	/* NOTREACHED */
    140 }
    141