src/logname.c

   1 /* logname -- print user's login name
   2    Copyright (C) 1990-1997, 1999-2005, 2007 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 #include <config.h>
  18 #include <stdio.h>
  19 #include <sys/types.h>
  20 #include <getopt.h>
  21
  22 #include "system.h"
  23 #include "error.h"
  24 #include "long-options.h"
  25 #include "quote.h"
  26
  27 /* The official name of this program (e.g., no `g' prefix).  */
  28 #define PROGRAM_NAME "logname"
  29
  30 #define AUTHORS proper_name ("FIXME: unknown")
  31
  32 /* The name this program was run with. */
  33 char *program_name;
  34
  35 void
  36 usage (int status)
  37 {
  38   if (status != EXIT_SUCCESS)
  39     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  40              program_name);
  41   else
  42     {
  43       printf (_("Usage: %s [OPTION]\n"), program_name);
  44       fputs (_("\
  45 Print the name of the current user.\n\
  46 \n\
  47 "), stdout);
  48       fputs (HELP_OPTION_DESCRIPTION, stdout);
  49       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  50       emit_bug_reporting_address ();
  51     }
  52   exit (status);
  53 }
  54
  55 int
  56 main (int argc, char **argv)
  57 {
  58   char *cp;
  59
  60   initialize_main (&argc, &argv);
  61   program_name = argv[0];
  62   setlocale (LC_ALL, "");
  63   bindtextdomain (PACKAGE, LOCALEDIR);
  64   textdomain (PACKAGE);
  65
  66   atexit (close_stdout);
  67
  68   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, VERSION,
  69                       usage, AUTHORS, (char const *) NULL);
  70   if (getopt_long (argc, argv, "", NULL, NULL) != -1)
  71     usage (EXIT_FAILURE);
  72
  73   if (optind < argc)
  74     {
  75       error (0, 0, _("extra operand %s"), quote (argv[optind]));
  76       usage (EXIT_FAILURE);
  77     }
  78
  79   /* POSIX requires using getlogin (or equivalent code).  */
  80   cp = getlogin ();
  81   if (cp)
  82     {
  83       puts (cp);
  84       exit (EXIT_SUCCESS);
  85     }
  86   /* POSIX prohibits using a fallback technique.  */
  87
  88   error (0, 0, _("no login name"));
  89   exit (EXIT_FAILURE);
  90 }