src/logname.c

   1 /* logname -- print user's login name
   2    Copyright (C) 90, 91, 92, 93, 94, 95, 1996 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 #include <config.h>
  19 #include <stdio.h>
  20 #include <sys/types.h>
  21 #include <getopt.h>
  22
  23 #include "system.h"
  24
  25 /* The name this program was run with. */
  26 char *program_name;
  27
  28 /* If nonzero, display usage information and exit.  */
  29 static int show_help;
  30
  31 /* If nonzero, print the version on standard output and exit.  */
  32 static int show_version;
  33
  34 static struct option const long_options[] =
  35 {
  36   {"help", no_argument, &show_help, 1},
  37   {"version", no_argument, &show_version, 1},
  38   {0, 0, 0, 0}
  39 };
  40
  41 static void
  42 usage (int status)
  43 {
  44   if (status != 0)
  45     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  46              program_name);
  47   else
  48     {
  49       printf (_("Usage: %s [OPTION]...\n"), program_name);
  50       printf (_("\
  51 Print the name of the current user.\n\
  52 \n\
  53   --help      display this help and exit\n\
  54   --version   output version information and exit\n\
  55 "));
  56       puts (_("\nReport bugs to sh-utils-bugs@gnu.ai.mit.edu"));
  57     }
  58   exit (status);
  59 }
  60
  61 int
  62 main (int argc, char **argv)
  63 {
  64   register char *cp;
  65   int c;
  66
  67   program_name = argv[0];
  68   setlocale (LC_ALL, "");
  69   bindtextdomain (PACKAGE, LOCALEDIR);
  70   textdomain (PACKAGE);
  71
  72   while ((c = getopt_long (argc, argv, "", long_options, (int *) 0)) != EOF)
  73     {
  74       switch (c)
  75         {
  76         case 0:
  77           break;
  78
  79         default:
  80           usage (1);
  81         }
  82     }
  83
  84   if (show_version)
  85     {
  86       printf ("logname (%s) %s\n", GNU_PACKAGE, VERSION);
  87       exit (0);
  88     }
  89
  90   if (show_help)
  91     usage (0);
  92
  93   if (argc - optind != 0)
  94     usage (1);
  95
  96   /* POSIX.2 requires using getlogin (or equivalent code).  */
  97   cp = getlogin ();
  98   if (cp)
  99     {
 100       puts (cp);
 101       exit (0);
 102     }
 103   /* POSIX.2 prohibits using a fallback technique.  */
 104   fprintf (stderr,_("%s: no login name\n"), argv[0]);
 105   exit (1);
 106 }