LXR 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> */
  21enum { VT_DISALLOCATE = 0x5608 }; /* free memory associated to vt */
  22
  23int deallocvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  24int 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}
  39