From 41ab4396e19fba338baf28044d3e48385744b930 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Thu, 18 Oct 2007 23:39:12 -0700 Subject: Console keyboard events and accessibility Some blind people use a kernel engine called Speakup which uses hardware synthesis to speak what gets displayed on the screen. They use the PC keyboard to control this engine (start/stop, accelerate, ...) and also need to get keyboard feedback (to make sure to know what they are typing, the caps lock status, etc.) Up to now, the way it was done was very ugly. Below is a patch to add a notifier list for permitting a far better implementation, see ChangeLog above for details. You may wonder why this can't be done at the input layer. The problem is that what people want to monitor is the console keyboard, i.e. all input keyboards that got attached to the console, and with the currently active keymap (i.e. keysyms, not only keycodes). This adds a keyboard notifier that such modules can use to get the keyboard events and possibly eat them, at several stages: - keycodes: even before translation into keysym. - unbound keycodes: when no keysym is bound. - unicode: when the keycode would get translated into a unicode character. - keysym: when the keycode would get translated into a keysym. - post_keysym: after the keysym got interpreted, so as to see the result (caps lock, etc.) This also provides access to k_handler so as to permit simulation of keypresses. [akpm@linux-foundation.org: various fixes] Signed-off-by: Samuel Thibault Cc: Jiri Kosina Cc: Dmitry Torokhov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/keyboard.c | 42 ++++++++++++++++++++++++++++++++++++------ 1 file changed, 36 insertions(+), 6 deletions(-) (limited to 'drivers/char/keyboard.c') diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c index 212276affa1f..d54f4a3ae340 100644 --- a/drivers/char/keyboard.c +++ b/drivers/char/keyboard.c @@ -42,6 +42,7 @@ #include #include #include +#include extern void ctrl_alt_del(void); @@ -81,7 +82,8 @@ void compute_shiftstate(void); typedef void (k_handler_fn)(struct vc_data *vc, unsigned char value, char up_flag); static k_handler_fn K_HANDLERS; -static k_handler_fn *k_handler[16] = { K_HANDLERS }; +k_handler_fn *k_handler[16] = { K_HANDLERS }; +EXPORT_SYMBOL_GPL(k_handler); #define FN_HANDLERS\ fn_null, fn_enter, fn_show_ptregs, fn_show_mem,\ @@ -159,6 +161,23 @@ static int sysrq_alt_use; #endif static int sysrq_alt; +/* + * Notifier list for console keyboard events + */ +static ATOMIC_NOTIFIER_HEAD(keyboard_notifier_list); + +int register_keyboard_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&keyboard_notifier_list, nb); +} +EXPORT_SYMBOL_GPL(register_keyboard_notifier); + +int unregister_keyboard_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&keyboard_notifier_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_keyboard_notifier); + /* * Translation of scancodes to keycodes. We set them on only the first * keyboard in the list that accepts the scancode and keycode. @@ -1130,6 +1149,7 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) unsigned char type, raw_mode; struct tty_struct *tty; int shift_final; + struct keyboard_notifier_param param = { .vc = vc, .value = keycode, .down = down }; tty = vc->vc_tty; @@ -1217,10 +1237,11 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) return; } - shift_final = (shift_state | kbd->slockstate) ^ kbd->lockstate; + param.shift = shift_final = (shift_state | kbd->slockstate) ^ kbd->lockstate; key_map = key_maps[shift_final]; - if (!key_map) { + if (atomic_notifier_call_chain(&keyboard_notifier_list, KBD_KEYCODE, ¶m) == NOTIFY_STOP || !key_map) { + atomic_notifier_call_chain(&keyboard_notifier_list, KBD_UNBOUND_KEYCODE, ¶m); compute_shiftstate(); kbd->slockstate = 0; return; @@ -1237,6 +1258,9 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) type = KTYP(keysym); if (type < 0xf0) { + param.value = keysym; + if (atomic_notifier_call_chain(&keyboard_notifier_list, KBD_UNICODE, ¶m) == NOTIFY_STOP) + return; if (down && !raw_mode) to_utf8(vc, keysym); return; @@ -1244,9 +1268,6 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) type -= 0xf0; - if (raw_mode && type != KT_SPEC && type != KT_SHIFT) - return; - if (type == KT_LETTER) { type = KT_LATIN; if (vc_kbd_led(kbd, VC_CAPSLOCK)) { @@ -1255,9 +1276,18 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw) keysym = key_map[keycode]; } } + param.value = keysym; + + if (atomic_notifier_call_chain(&keyboard_notifier_list, KBD_KEYSYM, ¶m) == NOTIFY_STOP) + return; + + if (raw_mode && type != KT_SPEC && type != KT_SHIFT) + return; (*k_handler[type])(vc, keysym & 0xff, !down); + atomic_notifier_call_chain(&keyboard_notifier_list, KBD_POST_KEYSYM, ¶m); + if (type != KT_SLOCK) kbd->slockstate = 0; } -- cgit v1.2.2