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 (status)
  57      int status;
  58 {
  59   if (status != 0)
  60     fprintf (stderr, "Try `%s --help' for more information.\n",
  61              program_name);
  62   else
  63     {
  64       printf ("\
  65 Usage: %s [NAME]\n\
  66   or:  %s OPTION\n\
  67 Print the hostname of the current system.\n\
  68 \n\
  69   --help      display this help and exit\n\
  70   --version   output version information and exit\n\
  71 "
  72              , program_name, program_name);
  73     }
  74   exit (status);
  75 }
  76
  77 void
  78 main (argc, argv)
  79      int argc;
  80      char **argv;
  81 {
  82   char *hostname;
  83
  84   program_name = argv[0];
  85
  86   parse_long_options (argc, argv, "hostname", version_string, usage);
  87
  88 #ifdef HAVE_SETHOSTNAME
  89   if (argc == 2)
  90     {
  91       int err;
  92
  93       /* Set hostname to argv[1].  */
  94       err = sethostname (argv[1], strlen (argv[1]));
  95       if (err != 0)
  96         error (1, errno, "%s", argv[1]);
  97       exit (0);
  98     }
  99 #else
 100   if (argc == 2)
 101     error (1, 0, "cannot set hostname; this system lacks the functionality");
 102 #endif
 103
 104   if (argc == 1)
 105     {
 106       hostname = xgethostname ();
 107       if (hostname == NULL)
 108         error (1, errno, "cannot determine hostname");
 109       printf ("%s\n", hostname);
 110     }
 111   else
 112     {
 113       error (2, 0, "too many arguments");
 114       usage (1);
 115     }
 116
 117   exit (0);
 118 }