src/hostname.c

   1 /* hostname - set or print the name of current host system
   2    Copyright (C) 1994-1997, 1999-2005, 2007-2011 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 3 of the License, or
   7    (at your option) 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, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Jim Meyering.  */
  18
  19 #include <config.h>
  20 #include <getopt.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23
  24 #include "system.h"
  25 #include "long-options.h"
  26 #include "error.h"
  27 #include "quote.h"
  28 #include "xgethostname.h"
  29
  30 /* The official name of this program (e.g., no `g' prefix).  */
  31 #define PROGRAM_NAME "hostname"
  32
  33 #define AUTHORS proper_name ("Jim Meyering")
  34
  35 #if !defined HAVE_SETHOSTNAME && defined HAVE_SYSINFO && \
  36      defined HAVE_SYS_SYSTEMINFO_H
  37 # include <sys/systeminfo.h>
  38
  39 static int
  40 sethostname (char *name, size_t namelen)
  41 {
  42   /* Using sysinfo() is the SVR4 mechanism to set a hostname. */
  43   return (sysinfo (SI_SET_HOSTNAME, name, namelen) < 0 ? -1 : 0);
  44 }
  45
  46 # define HAVE_SETHOSTNAME 1  /* Now we have it... */
  47 #endif
  48
  49 void
  50 usage (int status)
  51 {
  52   if (status != EXIT_SUCCESS)
  53     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  54              program_name);
  55   else
  56     {
  57       printf (_("\
  58 Usage: %s [NAME]\n\
  59   or:  %s OPTION\n\
  60 Print or set the hostname of the current system.\n\
  61 \n\
  62 "),
  63              program_name, program_name);
  64       fputs (HELP_OPTION_DESCRIPTION, stdout);
  65       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  66       emit_ancillary_info ();
  67     }
  68   exit (status);
  69 }
  70
  71 int
  72 main (int argc, char **argv)
  73 {
  74   char *hostname;
  75
  76   initialize_main (&argc, &argv);
  77   set_program_name (argv[0]);
  78   setlocale (LC_ALL, "");
  79   bindtextdomain (PACKAGE, LOCALEDIR);
  80   textdomain (PACKAGE);
  81
  82   atexit (close_stdout);
  83
  84   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
  85                       usage, AUTHORS, (char const *) NULL);
  86   if (getopt_long (argc, argv, "", NULL, NULL) != -1)
  87     usage (EXIT_FAILURE);
  88
  89   if (argc == optind + 1)
  90     {
  91 #ifdef HAVE_SETHOSTNAME
  92       /* Set hostname to operand.  */
  93       char const *name = argv[optind];
  94       if (sethostname (name, strlen (name)) != 0)
  95         error (EXIT_FAILURE, errno, _("cannot set name to %s"), quote (name));
  96 #else
  97       error (EXIT_FAILURE, 0,
  98              _("cannot set hostname; this system lacks the functionality"));
  99 #endif
 100     }
 101
 102   if (argc <= optind)
 103     {
 104       hostname = xgethostname ();
 105       if (hostname == NULL)
 106         error (EXIT_FAILURE, errno, _("cannot determine hostname"));
 107       printf ("%s\n", hostname);
 108     }
 109
 110   if (optind + 1 < argc)
 111     {
 112       error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
 113       usage (EXIT_FAILURE);
 114     }
 115
 116   exit (EXIT_SUCCESS);
 117 }