release/src/router/busybox/console-tools/deallocvt.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Disallocate virtual terminal(s)
   4  *
   5  * Copyright (C) 2003 by Tito Ragusa <farmatito@tiscali.it>
   6  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9  */
  10
  11 /* no options, no getopt */
  12
  13 //usage:#define deallocvt_trivial_usage
  14 //usage:       "[N]"
  15 //usage:#define deallocvt_full_usage "\n\n"
  16 //usage:       "Deallocate unused virtual terminal /dev/ttyN"
  17
  18 #include "libbb.h"
  19
  20 /* From <linux/vt.h> */
  21 enum { VT_DISALLOCATE = 0x5608 }; /* free memory associated to vt */
  22
  23 int deallocvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  24 int deallocvt_main(int argc UNUSED_PARAM, char **argv)
  25 {
  26         /* num = 0 deallocate all unused consoles */
  27         int num = 0;
  28
  29         if (argv[1]) {
  30                 if (argv[2])
  31                         bb_show_usage();
  32                 num = xatou_range(argv[1], 1, 63);
  33         }
  34
  35         /* double cast suppresses "cast to ptr from int of different size" */
  36         xioctl(get_console_fd_or_die(), VT_DISALLOCATE, (void *)(ptrdiff_t)num);
  37         return EXIT_SUCCESS;
  38 }