src/readlink.c

   1 /* readlink -- display value of a symbolic link.
   2    Copyright (C) 2002, 2003 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by Dmitry V. Levin */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <limits.h>
  25 #include <getopt.h>
  26
  27 #include "system.h"
  28 #include "canonicalize.h"
  29 #include "error.h"
  30 #include "xreadlink.h"
  31 #include "long-options.h"
  32 #include "quote.h"
  33
  34 /* The official name of this program (e.g., no `g' prefix).  */
  35 #define PROGRAM_NAME "readlink"
  36
  37 #define AUTHORS "Dmitry V. Levin"
  38
  39 /* Name this program was run with.  */
  40 char *program_name;
  41
  42   /* If nonzero, canonicalize file name. */
  43 static int canonicalize;
  44   /* If nonzero, do not output the trailing newline. */
  45 static int no_newline;
  46   /* If nonzero, report error messages. */
  47 static int verbose;
  48
  49 static struct option const longopts[] =
  50 {
  51   {"canonicalize", no_argument, 0, 'f'},
  52   {"no-newline", no_argument, 0, 'n'},
  53   {"quiet", no_argument, 0, 'q'},
  54   {"silent", no_argument, 0, 's'},
  55   {"verbose", no_argument, 0, 'v'},
  56   {GETOPT_HELP_OPTION_DECL},
  57   {GETOPT_VERSION_OPTION_DECL},
  58   {NULL, 0, NULL, 0}
  59 };
  60
  61 void
  62 usage (int status)
  63 {
  64   if (status != EXIT_SUCCESS)
  65     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  66              program_name);
  67   else
  68     {
  69       printf (_("Usage: %s [OPTION]... FILE\n"), program_name);
  70       fputs (_("Display value of a symbolic link on standard output.\n\n"),
  71              stdout);
  72       fputs (_("\
  73   -f, --canonicalize      canonicalize by following every symlink in every\n\
  74                           component of the given path recursively\n\
  75   -n, --no-newline        do not output the trailing newline\n\
  76   -q, --quiet,\n\
  77   -s, --silent            suppress most error messages\n\
  78   -v, --verbose           report error messages\n\
  79 "), stdout);
  80       fputs (HELP_OPTION_DESCRIPTION, stdout);
  81       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  82       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  83     }
  84   exit (status);
  85 }
  86
  87 int
  88 main (int argc, char *const argv[])
  89 {
  90   const char *fname;
  91   char *value;
  92   int optc;
  93
  94   setlocale (LC_ALL, "");
  95   bindtextdomain (PACKAGE, LOCALEDIR);
  96   textdomain (PACKAGE);
  97
  98   atexit (close_stdout);
  99
 100   if (argc < 1)
 101     error (EXIT_FAILURE, 0, _("too few arguments"));
 102
 103   program_name = argv[0];
 104
 105   while ((optc = getopt_long (argc, argv, "fnqsv", longopts, NULL)) != -1)
 106     {
 107       switch (optc)
 108         {
 109         case 0:
 110           break;
 111         case 'f':
 112           canonicalize = 1;
 113           break;
 114         case 'n':
 115           no_newline = 1;
 116           break;
 117         case 'q':
 118         case 's':
 119           verbose = 0;
 120           break;
 121         case 'v':
 122           verbose = 1;
 123           break;
 124         case_GETOPT_HELP_CHAR;
 125         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 126         default:
 127           usage (EXIT_FAILURE);
 128         }
 129     }
 130
 131   if (optind >= argc)
 132     {
 133       error (EXIT_SUCCESS, 0, _("too few arguments"));
 134       usage (EXIT_FAILURE);
 135     }
 136
 137   fname = argv[optind++];
 138
 139   if (optind < argc)
 140     {
 141       error (EXIT_SUCCESS, 0, _("too many arguments"));
 142       usage (EXIT_FAILURE);
 143     }
 144
 145   value = (canonicalize ? canonicalize_file_name : xreadlink) (fname);
 146   if (value)
 147     {
 148       printf ("%s%s", value, (no_newline ? "" : "\n"));
 149       free (value);
 150       return EXIT_SUCCESS;
 151     }
 152
 153   if (verbose)
 154     error (EXIT_SUCCESS, errno, "%s", fname);
 155
 156   return EXIT_FAILURE;
 157 }