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 <getopt.h>
  23 #include <sys/types.h>
  24
  25 #include "system.h"
  26 #include "canonicalize.h"
  27 #include "error.h"
  28 #include "xreadlink.h"
  29 #include "long-options.h"
  30 #include "quote.h"
  31
  32 /* The official name of this program (e.g., no `g' prefix).  */
  33 #define PROGRAM_NAME "readlink"
  34
  35 #define AUTHORS "Dmitry V. Levin"
  36
  37 /* Name this program was run with.  */
  38 char *program_name;
  39
  40   /* If nonzero, canonicalize file name. */
  41 static int canonicalize;
  42   /* If nonzero, do not output the trailing newline. */
  43 static int no_newline;
  44   /* If nonzero, report error messages. */
  45 static int verbose;
  46
  47 static struct option const longopts[] =
  48 {
  49   {"canonicalize", no_argument, 0, 'f'},
  50   {"no-newline", no_argument, 0, 'n'},
  51   {"quiet", no_argument, 0, 'q'},
  52   {"silent", no_argument, 0, 's'},
  53   {"verbose", no_argument, 0, 'v'},
  54   {GETOPT_HELP_OPTION_DECL},
  55   {GETOPT_VERSION_OPTION_DECL},
  56   {NULL, 0, NULL, 0}
  57 };
  58
  59 void
  60 usage (int status)
  61 {
  62   if (status != EXIT_SUCCESS)
  63     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  64              program_name);
  65   else
  66     {
  67       printf (_("Usage: %s [OPTION]... FILE\n"), program_name);
  68       fputs (_("Display value of a symbolic link on standard output.\n\n"),
  69              stdout);
  70       fputs (_("\
  71   -f, --canonicalize      canonicalize by following every symlink in every\n\
  72                           component of the given path recursively\n\
  73   -n, --no-newline        do not output the trailing newline\n\
  74   -q, --quiet,\n\
  75   -s, --silent            suppress most error messages\n\
  76   -v, --verbose           report error messages\n\
  77 "), stdout);
  78       fputs (HELP_OPTION_DESCRIPTION, stdout);
  79       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  80       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  81     }
  82   exit (status);
  83 }
  84
  85 int
  86 main (int argc, char *const argv[])
  87 {
  88   const char *fname;
  89   char *value;
  90   int optc;
  91
  92   initialize_main (&argc, &argv);
  93   program_name = argv[0];
  94   setlocale (LC_ALL, "");
  95   bindtextdomain (PACKAGE, LOCALEDIR);
  96   textdomain (PACKAGE);
  97
  98   atexit (close_stdout);
  99
 100   while ((optc = getopt_long (argc, argv, "fnqsv", longopts, NULL)) != -1)
 101     {
 102       switch (optc)
 103         {
 104         case 0:
 105           break;
 106         case 'f':
 107           canonicalize = 1;
 108           break;
 109         case 'n':
 110           no_newline = 1;
 111           break;
 112         case 'q':
 113         case 's':
 114           verbose = 0;
 115           break;
 116         case 'v':
 117           verbose = 1;
 118           break;
 119         case_GETOPT_HELP_CHAR;
 120         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 121         default:
 122           usage (EXIT_FAILURE);
 123         }
 124     }
 125
 126   if (optind >= argc)
 127     {
 128       error (0, 0, _("too few arguments"));
 129       usage (EXIT_FAILURE);
 130     }
 131
 132   fname = argv[optind++];
 133
 134   if (optind < argc)
 135     {
 136       error (0, 0, _("too many arguments"));
 137       usage (EXIT_FAILURE);
 138     }
 139
 140   value = (canonicalize ? canonicalize_file_name : xreadlink) (fname);
 141   if (value)
 142     {
 143       printf ("%s%s", value, (no_newline ? "" : "\n"));
 144       free (value);
 145       return EXIT_SUCCESS;
 146     }
 147
 148   if (verbose)
 149     error (EXIT_FAILURE, errno, "%s", fname);
 150
 151   return EXIT_FAILURE;
 152 }