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pwd.c revision 1.14 
      1 /* $NetBSD: pwd.c,v 1.14 2001/09/16 22:11:56 wiz 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 __COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\n\
     39 	The Regents of the University of California.  All rights reserved.\n");
     40 #endif /* not lint */
     41 
     42 #ifndef lint
     43 #if 0
     44 static char sccsid[] = "@(#)pwd.c	8.3 (Berkeley) 4/1/94";
     45 #else
     46 __RCSID("$NetBSD: pwd.c,v 1.14 2001/09/16 22:11:56 wiz Exp $");
     47 #endif
     48 #endif /* not lint */
     49 
     50 #include <sys/types.h>
     51 #include <sys/stat.h>
     52 
     53 #include <err.h>
     54 #include <errno.h>
     55 #include <stdio.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <unistd.h>
     59 
     60 static char *getcwd_logical(char *, size_t);
     61 static void usage(void);
     62 int main(int, char *[]);
     63 
     64 int
     65 main(int argc, char *argv[])
     66 {
     67 	int ch, lFlag;
     68 	const char *p;
     69 
     70 	setprogname(argv[0]);
     71 	lFlag = 0;
     72 	while ((ch = getopt(argc, argv, "LP")) != -1)
     73 		switch (ch) {
     74 		case 'L':
     75 			lFlag = 1;
     76 			break;
     77 		case 'P':
     78 			lFlag = 0;
     79 			break;
     80 		case '?':
     81 		default:
     82 			usage();
     83 		}
     84 	argc -= optind;
     85 	argv += optind;
     86 
     87 	if (argc != 0)
     88 		usage();
     89 
     90 	if (lFlag)
     91 		p = getcwd_logical(NULL, 0);
     92 	else
     93 		p = getcwd(NULL, 0);
     94 
     95 	if (p == NULL)
     96 		err(EXIT_FAILURE, NULL);
     97 
     98 	(void)printf("%s\n", p);
     99 
    100 	exit(EXIT_SUCCESS);
    101 	/* NOTREACHED */
    102 }
    103 
    104 static char *
    105 getcwd_logical(char *pt, size_t size)
    106 {
    107 	char *pwd;
    108 	size_t pwdlen;
    109 	dev_t dev;
    110 	ino_t ino;
    111 	struct stat s;
    112 
    113 	/* Check $PWD -- if it's right, it's fast. */
    114 	if ((pwd = getenv("PWD")) != NULL && pwd[0] == '/') {
    115 		if (stat(pwd, &s) != -1) {
    116 			dev = s.st_dev;
    117 			ino = s.st_ino;
    118 			if (stat(".", &s) != -1 && dev == s.st_dev &&
    119 			    ino == s.st_ino) {
    120 				pwdlen = strlen(pwd);
    121 				if (pt) {
    122 					if (!size) {
    123 						errno = EINVAL;
    124 						return (NULL);
    125 					}
    126 					if (pwdlen + 1 > size) {
    127 						errno = ERANGE;
    128 						return (NULL);
    129 					}
    130 				} else if ((pt = malloc(pwdlen + 1)) == NULL)
    131 					return (NULL);
    132 				(void)memmove(pt, pwd, pwdlen);
    133 				pt[pwdlen] = '\0';
    134 				return (pt);
    135 			}
    136 		}
    137 	} else
    138 		errno = ENOENT;
    139 
    140 	return (NULL);
    141 }
    142 
    143 static void
    144 usage(void)
    145 {
    146 	(void)fprintf(stderr, "usage: %s [-LP]\n", getprogname());
    147 	exit(EXIT_FAILURE);
    148 	/* NOTREACHED */
    149 }
    150