src/hostid.c

   1 /* print the hexadecimal identifier for the current host
   2
   3    Copyright (C) 1997, 1999, 2000, 2001, 2002, 2003, 2004 Free
   4    Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 /* Written by Jim Meyering.  */
  21
  22 #include <config.h>
  23 #include <getopt.h>
  24 #include <stdio.h>
  25 #include <sys/types.h>
  26
  27 #include "system.h"
  28 #include "long-options.h"
  29 #include "error.h"
  30 #include "quote.h"
  31
  32 /* The official name of this program (e.g., no `g' prefix).  */
  33 #define PROGRAM_NAME "hostid"
  34
  35 #define AUTHORS "Jim Meyering"
  36
  37 /* The name this program was run with, for error messages. */
  38 char *program_name;
  39
  40 void
  41 usage (int status)
  42 {
  43   if (status != EXIT_SUCCESS)
  44     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  45              program_name);
  46   else
  47     {
  48       printf (_("\
  49 Usage: %s\n\
  50   or:  %s OPTION\n\
  51 Print the numeric identifier (in hexadecimal) for the current host.\n\
  52 \n\
  53 "),
  54               program_name, program_name);
  55       fputs (HELP_OPTION_DESCRIPTION, stdout);
  56       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  57       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
  58     }
  59   exit (status);
  60 }
  61
  62 int
  63 main (int argc, char **argv)
  64 {
  65   unsigned int id;
  66
  67   initialize_main (&argc, &argv);
  68   program_name = argv[0];
  69   setlocale (LC_ALL, "");
  70   bindtextdomain (PACKAGE, LOCALEDIR);
  71   textdomain (PACKAGE);
  72
  73   atexit (close_stdout);
  74
  75   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
  76                       usage, AUTHORS, (char const *) NULL);
  77   if (getopt_long (argc, argv, "", NULL, NULL) != -1)
  78     usage (EXIT_FAILURE);
  79
  80   if (optind < argc)
  81     {
  82       error (0, 0, _("extra operand %s"), quote (argv[optind]));
  83       usage (EXIT_FAILURE);
  84     }
  85
  86   id = gethostid ();
  87
  88   /* POSIX says gethostid returns a "32-bit identifier" but is silent
  89      whether it's sign-extended.  Turn off any sign-extension.  This
  90      is a no-op unless unsigned int is wider than 32 bits.  */
  91   id &= 0xffffffff;
  92
  93   printf ("%08x\n", id);
  94
  95   exit (EXIT_SUCCESS);
  96 }