vt: Add virtual console keyboard mode OFF

virtual console: add keyboard mode OFF

Add a new mode for the virtual console keyboard OFF in which all input
other than shift keys is ignored. Prevents vt input buffers from
overflowing when a program opens but doesn't read from a tty, like X11
using evdev for input.

Signed-off-by: Arthur Taylor <art@ified.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Arthur Taylor 2011-02-04 13:55:50 -08:00 committed by Greg Kroah-Hartman
parent 8e6d3fe1af
commit 9fc3de9c83
4 changed files with 9 additions and 3 deletions

View file

@ -654,7 +654,8 @@ static void k_spec(struct vc_data *vc, unsigned char value, char up_flag)
if (value >= ARRAY_SIZE(fn_handler))
return;
if ((kbd->kbdmode == VC_RAW ||
kbd->kbdmode == VC_MEDIUMRAW) &&
kbd->kbdmode == VC_MEDIUMRAW ||
kbd->kbdmode == VC_OFF) &&
value != KVAL(K_SAK))
return; /* SAK is allowed even in raw mode */
fn_handler[value](vc);
@ -1295,7 +1296,7 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw)
if (rc == NOTIFY_STOP)
return;
if (raw_mode && type != KT_SPEC && type != KT_SHIFT)
if ((raw_mode || kbd->kbdmode == VC_OFF) && type != KT_SPEC && type != KT_SHIFT)
return;
(*k_handler[type])(vc, keysym & 0xff, !down);

View file

@ -688,6 +688,9 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
kbd->kbdmode = VC_UNICODE;
compute_shiftstate();
break;
case K_OFF:
kbd->kbdmode = VC_OFF;
break;
default:
ret = -EINVAL;
goto out;

View file

@ -50,11 +50,12 @@ struct kbd_struct {
#define VC_CAPSLOCK 2 /* capslock mode */
#define VC_KANALOCK 3 /* kanalock mode */
unsigned char kbdmode:2; /* one 2-bit value */
unsigned char kbdmode:3; /* one 3-bit value */
#define VC_XLATE 0 /* translate keycodes using keymap */
#define VC_MEDIUMRAW 1 /* medium raw (keycode) mode */
#define VC_RAW 2 /* raw (scancode) mode */
#define VC_UNICODE 3 /* Unicode mode */
#define VC_OFF 4 /* disabled mode */
unsigned char modeflags:5;
#define VC_APPLIC 0 /* application key mode */

View file

@ -81,6 +81,7 @@ struct unimapinit {
#define K_XLATE 0x01
#define K_MEDIUMRAW 0x02
#define K_UNICODE 0x03
#define K_OFF 0x04
#define KDGKBMODE 0x4B44 /* gets current keyboard mode */
#define KDSKBMODE 0x4B45 /* sets current keyboard mode */