login/programs/utmpdump.c

   1 /* utmpdump - dump utmp-like files.
   2    Copyright (C) 1997-2020 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Mark Kettenis <kettenis@phys.uva.nl>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <time.h>
  23 #include <unistd.h>
  24 #include <utmp.h>
  25
  26 static void
  27 print_entry (struct utmp *up)
  28 {
  29   /* Mixed 32-/64-bit systems may have timeval structs of different sixe
  30      but need struct utmp to be the same size.  So in 64-bit up->ut_tv may
  31      not be a timeval but a struct of __int32_t's.  This would cause a compile
  32      time warning and a formating error when 32-bit int is passed where
  33      a 64-bit long is expected. So copy up->up_tv to a temporary timeval.
  34      This is 32-/64-bit agnostic and expands the timeval fields to the
  35      expected size as needed. */
  36   struct timeval temp_tv;
  37   temp_tv.tv_sec = up->ut_tv.tv_sec;
  38   temp_tv.tv_usec = up->ut_tv.tv_usec;
  39
  40   printf ("[%d] [%05d] [%-4.4s] [%-8.8s] [%-12.12s] [%-16.16s] [%-15.15s]"
  41           " [%ld]\n",
  42           up->ut_type, up->ut_pid, up->ut_id, up->ut_user, up->ut_line,
  43           up->ut_host, 4 + ctime (&temp_tv.tv_sec),
  44           (long int) temp_tv.tv_usec);
  45 }
  46
  47 int
  48 main (int argc, char *argv[])
  49 {
  50   struct utmp *up;
  51
  52   if (argc > 1)
  53     utmpname (argv[1]);
  54
  55   setutent ();
  56
  57   while ((up = getutent ()))
  58     print_entry (up);
  59
  60   endutent ();
  61
  62   return EXIT_SUCCESS;
  63 }