bin/pwd/pwd.c

   1 /* $NetBSD: pwd.c,v 1.22 2011/08/29 14:51:19 joerg 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
  40 static char sccsid[] = "@(#)pwd.c       8.3 (Berkeley) 4/1/94";
  41 #else
  42 __RCSID("$NetBSD: pwd.c,v 1.22 2011/08/29 14:51:19 joerg 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 __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
  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 }