console-tools/fgconsole.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini fgconsole implementation for busybox
   4  *
   5  * Copyright (C) 2010 by Grigory Batalov <bga@altlinux.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config FGCONSOLE
  10 //config:       bool "fgconsole (1.8 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       This program prints active (foreground) console number.
  14
  15 //applet:IF_FGCONSOLE(APPLET_NOEXEC(fgconsole, fgconsole, BB_DIR_USR_BIN, BB_SUID_DROP, fgconsole))
  16
  17 //kbuild:lib-$(CONFIG_FGCONSOLE) += fgconsole.o
  18
  19 //usage:#define fgconsole_trivial_usage
  20 //usage:        ""
  21 //usage:#define fgconsole_full_usage "\n\n"
  22 //usage:        "Get active console"
  23
  24 #include "libbb.h"
  25
  26 /* From <linux/vt.h> */
  27 struct vt_stat {
  28         unsigned short v_active;        /* active vt */
  29         unsigned short v_signal;        /* signal to send */
  30         unsigned short v_state;         /* vt bitmask */
  31 };
  32 enum { VT_GETSTATE = 0x5603 }; /* get global vt state info */
  33
  34 int fgconsole_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  35 int fgconsole_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  36 {
  37         struct vt_stat vtstat;
  38
  39         vtstat.v_active = 0;
  40         xioctl(get_console_fd_or_die(), VT_GETSTATE, &vtstat);
  41         printf("%d\n", vtstat.v_active);
  42
  43         return EXIT_SUCCESS;
  44 }