src/whoami.c

   1 /* whoami -- print effective userid
   2    Copyright (C) 89,90, 1991-1997, 1999 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 /* Equivalent to `id -un'. */
  19 /* Written by Richard Mlynarik. */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <sys/types.h>
  24 #include <pwd.h>
  25 #include <getopt.h>
  26
  27 #include "system.h"
  28 #include "long-options.h"
  29
  30 /* The official name of this program (e.g., no `g' prefix).  */
  31 #define PROGRAM_NAME "whoami"
  32
  33 #define AUTHORS "Richard Mlynarik"
  34
  35 /* The name this program was run with. */
  36 char *program_name;
  37
  38 static struct option const long_options[] =
  39 {
  40   {0, 0, 0, 0}
  41 };
  42
  43 void
  44 usage (int status)
  45 {
  46   if (status != 0)
  47     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  48              program_name);
  49   else
  50     {
  51       printf (_("Usage: %s [OPTION]...\n"), program_name);
  52       printf (_("\
  53 Print the user name associated with the current effective user id.\n\
  54 Same as id -un.\n\
  55 \n\
  56   --help      display this help and exit\n\
  57   --version   output version information and exit\n"));
  58       puts (_("\nReport bugs to <bug-sh-utils@gnu.org>."));
  59     }
  60   exit (status);
  61 }
  62
  63 int
  64 main (int argc, char **argv)
  65 {
  66   register struct passwd *pw;
  67   register uid_t uid;
  68   int c;
  69
  70   program_name = argv[0];
  71   setlocale (LC_ALL, "");
  72   bindtextdomain (PACKAGE, LOCALEDIR);
  73   textdomain (PACKAGE);
  74
  75   parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION,
  76                       AUTHORS, usage);
  77
  78   while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
  79     {
  80       switch (c)
  81         {
  82         case 0:
  83           break;
  84
  85         default:
  86           usage (1);
  87         }
  88     }
  89
  90   if (optind != argc)
  91     usage (1);
  92
  93   uid = geteuid ();
  94   pw = getpwuid (uid);
  95   if (pw)
  96     {
  97       puts (pw->pw_name);
  98       exit (0);
  99     }
 100   fprintf (stderr, _("%s: cannot find username for UID %u\n"),
 101            program_name, (unsigned) uid);
 102   exit (1);
 103 }