src/hostname.c

   1 /* hostname - set or print the name of current host system
   2    Copyright (C) 94, 1995 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
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 /* Jim Meyering <meyering@comco.com> */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23
  24 #include "system.h"
  25 #include "version.h"
  26 #include "long-options.h"
  27 #include "error.h"
  28
  29 #if !defined(HAVE_SETHOSTNAME) && defined(HAVE_SYSINFO) && \
  30      defined (HAVE_SYS_SYSTEMINFO_H) && defined(HAVE_LIMITS_H)
  31 #include <limits.h>
  32 #include <sys/systeminfo.h>
  33
  34 int
  35 sethostname (name, namelen)
  36      char *name;
  37      int namelen;
  38 {
  39   /* Using sysinfo() is the SVR4 mechanism to set a hostname. */
  40   int result;
  41
  42   result = sysinfo (SI_SET_HOSTNAME, name, namelen);
  43
  44   return (result == -1 ? result : 0);
  45 }
  46
  47 #define HAVE_SETHOSTNAME 1  /* Now we have it... */
  48 #endif
  49
  50 char *xgethostname ();
  51
  52 /* The name this program was run with. */
  53 char *program_name;
  54
  55 static void
  56 usage (int status)
  57 {
  58   if (status != 0)
  59     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  60              program_name);
  61   else
  62     {
  63       printf (_("\
  64 Usage: %s [NAME]\n\
  65   or:  %s OPTION\n\
  66 Print the hostname of the current system.\n\
  67 \n\
  68   --help      display this help and exit\n\
  69   --version   output version information and exit\n\
  70 ")
  71              , program_name, program_name);
  72     }
  73   exit (status);
  74 }
  75
  76 void
  77 main (int argc, char **argv)
  78 {
  79   char *hostname;
  80
  81   program_name = argv[0];
  82
  83   parse_long_options (argc, argv, "hostname", version_string, usage);
  84
  85 #ifdef HAVE_SETHOSTNAME
  86   if (argc == 2)
  87     {
  88       int err;
  89
  90       /* Set hostname to argv[1].  */
  91       err = sethostname (argv[1], strlen (argv[1]));
  92       if (err != 0)
  93         error (1, errno, "%s", argv[1]);
  94       exit (0);
  95     }
  96 #else
  97   if (argc == 2)
  98     error (1, 0,
  99            _("cannot set hostname; this system lacks the functionality"));
 100 #endif
 101
 102   if (argc == 1)
 103     {
 104       hostname = xgethostname ();
 105       if (hostname == NULL)
 106         error (1, errno, _("cannot determine hostname"));
 107       printf ("%s\n", hostname);
 108     }
 109   else
 110     {
 111       error (2, 0, _("too many arguments"));
 112       usage (1);
 113     }
 114
 115   exit (0);
 116 }