src/users.c

   1 /* GNU's users.
   2    Copyright (C) 92, 93, 94, 95, 96, 1997 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 /* Written by jla; revised by djm */
  19
  20 #include <config.h>
  21 #include <getopt.h>
  22
  23 #include "system.h"
  24 #include "error.h"
  25 #include "readutmp.h"
  26
  27 /* The name this program was run with. */
  28 char *program_name;
  29
  30 /* If nonzero, display usage information and exit.  */
  31 static int show_help;
  32
  33 /* If nonzero, print the version on standard output and exit.  */
  34 static int show_version;
  35
  36 static struct option const longopts[] =
  37 {
  38   {"help", no_argument, &show_help, 1},
  39   {"version", no_argument, &show_version, 1},
  40   {NULL, 0, NULL, 0}
  41 };
  42
  43 static int
  44 userid_compare (const void *v_a, const void *v_b)
  45 {
  46   char **a = (char **) v_a;
  47   char **b = (char **) v_b;
  48   return strcmp (*a, *b);
  49 }
  50
  51 static void
  52 list_entries_users (int n, const STRUCT_UTMP *this)
  53 {
  54   char **u;
  55   int i;
  56   int n_entries;
  57
  58   n_entries = 0;
  59   u = (char **) xmalloc (n * sizeof (u[0]));
  60   for (i = 0; i < n; i++)
  61     {
  62       if (this->ut_name[0]
  63 #ifdef USER_PROCESS
  64           && this->ut_type == USER_PROCESS
  65 #endif
  66           )
  67         {
  68           char *trimmed_name;
  69
  70           trimmed_name = extract_trimmed_name (this);
  71
  72           u[n_entries] = trimmed_name;
  73           ++n_entries;
  74         }
  75       this++;
  76     }
  77
  78   qsort (u, n_entries, sizeof (u[0]), userid_compare);
  79
  80   for (i = 0; i < n_entries; i++)
  81     {
  82       int c;
  83       fputs (u[i], stdout);
  84       c = (i < n_entries - 1 ? ' ' : '\n');
  85       putchar (c);
  86     }
  87
  88   for (i = 0; i < n_entries; i++)
  89     free (u[i]);
  90   free (u);
  91 }
  92
  93 /* Display a list of users on the system, according to utmp file FILENAME. */
  94
  95 static void
  96 users (const char *filename)
  97 {
  98   int n_users;
  99   STRUCT_UTMP *utmp_buf;
 100   int fail = read_utmp (filename, &n_users, &utmp_buf);
 101
 102   if (fail)
 103     error (1, errno, "%s", filename);
 104
 105   list_entries_users (n_users, utmp_buf);
 106 }
 107
 108 static void
 109 usage (int status)
 110 {
 111   if (status != 0)
 112     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 113              program_name);
 114   else
 115     {
 116       printf (_("Usage: %s [OPTION]... [ FILE ]\n"), program_name);
 117       printf (_("\
 118 Output who is currently logged in according to FILE.\n\
 119 If FILE is not specified, use %s.  %s as FILE is common.\n\
 120 \n\
 121       --help        display this help and exit\n\
 122       --version     output version information and exit\n"),
 123               UTMP_FILE, WTMP_FILE);
 124       puts (_("\nReport bugs to <sh-utils-bugs@gnu.org>."));
 125     }
 126   exit (status);
 127 }
 128
 129 int
 130 main (int argc, char **argv)
 131 {
 132   int optc, longind;
 133   program_name = argv[0];
 134   setlocale (LC_ALL, "");
 135   bindtextdomain (PACKAGE, LOCALEDIR);
 136   textdomain (PACKAGE);
 137
 138   while ((optc = getopt_long (argc, argv, "", longopts, &longind)) != -1)
 139     {
 140       switch (optc)
 141         {
 142         case 0:
 143           break;
 144
 145         default:
 146           usage (1);
 147         }
 148     }
 149
 150   if (show_version)
 151     {
 152       printf ("users (%s) %s\n", GNU_PACKAGE, VERSION);
 153       exit (0);
 154     }
 155
 156   if (show_help)
 157     usage (0);
 158
 159   switch (argc - optind)
 160     {
 161     case 0:                     /* users */
 162       users (UTMP_FILE);
 163       break;
 164
 165     case 1:                     /* users <utmp file> */
 166       users (argv[optind]);
 167       break;
 168
 169     default:                    /* lose */
 170       error (0, 0, _("too many arguments"));
 171       usage (1);
 172     }
 173
 174   exit (0);
 175 }