bin/pwd/pwd.c

   1 /*-
   2  * Copyright (c) 1991, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)pwd.c    8.3 (Berkeley) 4/1/94
  30  * $FreeBSD: head/bin/pwd/pwd.c 141578 2005-02-09 17:37:39Z ru $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/stat.h>
  35 #include <sys/types.h>
  36
  37 #include <err.h>
  38 #include <errno.h>
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42
  43 static char *getcwd_logical(void);
  44 static void usage(void) __dead2;
  45
  46 int
  47 main(int argc, char *argv[])
  48 {
  49         int physical;
  50         int ch;
  51         char *p;
  52
  53         physical = 1;
  54         while ((ch = getopt(argc, argv, "LP")) != -1)
  55                 switch (ch) {
  56                 case 'L':
  57                         physical = 0;
  58                         break;
  59                 case 'P':
  60                         physical = 1;
  61                         break;
  62                 case '?':
  63                 default:
  64                         usage();
  65                 }
  66         argc -= optind;
  67         argv += optind;
  68
  69         if (argc != 0)
  70                 usage();
  71
  72         /*
  73          * If we're trying to find the logical current directory and that
  74          * fails, behave as if -P was specified.
  75          */
  76         if ((!physical && (p = getcwd_logical()) != NULL) ||
  77             (p = getcwd(NULL, 0)) != NULL)
  78                 printf("%s\n", p);
  79         else
  80                 err(1, ".");
  81
  82         exit(0);
  83 }
  84
  85 static void
  86 usage(void)
  87 {
  88
  89         fprintf(stderr, "usage: pwd [-L | -P]\n");
  90         exit(1);
  91 }
  92
  93 static char *
  94 getcwd_logical(void)
  95 {
  96         struct stat logic, phy;
  97         char *pwd;
  98
  99         /*
 100          * Check that $PWD is an absolute logical pathname referring to
 101          * the current working directory.
 102          */
 103         if ((pwd = getenv("PWD")) != NULL && *pwd == '/') {
 104                 if (stat(pwd, &logic) == -1 || stat(".", &phy) == -1)
 105                         return (NULL);
 106                 if (logic.st_dev == phy.st_dev && logic.st_ino == phy.st_ino)
 107                         return (pwd);
 108         }
 109
 110         errno = ENOENT;
 111         return (NULL);
 112 }