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Commit 5fdbe44d authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: do not pass injected events back to the originating handler 



Sometimes input handlers (as opposed to input devices) have a need to
inject (or re-inject) events back into input core. For example sysrq
filter may want to inject previously suppressed Alt-SysRq so that user
can take a screen print. In this case we do not want to pass such events
back to the same same handler that injected them to avoid loops.

Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 17d01f28

drivers/input/input.c

+26 −11
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ static int input_defuzz_abs_event(int value, int old_val, int fuzz) 
 * dev->event_lock held and interrupts disabled.

 */

static void input_pass_event(struct input_dev *dev,

			     struct input_handler *src_handler,

			     unsigned int type, unsigned int code, int value)

{

	struct input_handler *handler;
@@ -92,6 +93,15 @@ static void input_pass_event(struct input_dev *dev, 
				continue;



			handler = handle->handler;



			/*

			 * If this is the handler that injected this

			 * particular event we want to skip it to avoid

			 * filters firing again and again.

			 */

			if (handler == src_handler)

				continue;



			if (!handler->filter) {

				if (filtered)

					break;
@@ -121,7 +131,7 @@ static void input_repeat_key(unsigned long data) 
	if (test_bit(dev->repeat_key, dev->key) &&

	    is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {



		input_pass_event(dev, EV_KEY, dev->repeat_key, 2);

		input_pass_event(dev, NULL, EV_KEY, dev->repeat_key, 2);



		if (dev->sync) {

			/*
@@ -130,7 +140,7 @@ static void input_repeat_key(unsigned long data) 
			 * Otherwise assume that the driver will send

			 * SYN_REPORT once it's done.

			 */

			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);

			input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);

		}



		if (dev->rep[REP_PERIOD])
@@ -163,6 +173,7 @@ static void input_stop_autorepeat(struct input_dev *dev) 
#define INPUT_PASS_TO_ALL	(INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)



static int input_handle_abs_event(struct input_dev *dev,

				  struct input_handler *src_handler,

				  unsigned int code, int *pval)

{

	bool is_mt_event;
@@ -206,13 +217,15 @@ static int input_handle_abs_event(struct input_dev *dev, 
	/* Flush pending "slot" event */

	if (is_mt_event && dev->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {

		input_abs_set_val(dev, ABS_MT_SLOT, dev->slot);

		input_pass_event(dev, EV_ABS, ABS_MT_SLOT, dev->slot);

		input_pass_event(dev, src_handler,

				 EV_ABS, ABS_MT_SLOT, dev->slot);

	}



	return INPUT_PASS_TO_HANDLERS;

}



static void input_handle_event(struct input_dev *dev,

			       struct input_handler *src_handler,

			       unsigned int type, unsigned int code, int value)

{

	int disposition = INPUT_IGNORE_EVENT;
@@ -265,7 +278,8 @@ static void input_handle_event(struct input_dev *dev, 


	case EV_ABS:

		if (is_event_supported(code, dev->absbit, ABS_MAX))

			disposition = input_handle_abs_event(dev, code, &value);

			disposition = input_handle_abs_event(dev, src_handler,

							     code, &value);



		break;
@@ -323,7 +337,7 @@ static void input_handle_event(struct input_dev *dev, 
		dev->event(dev, type, code, value);



	if (disposition & INPUT_PASS_TO_HANDLERS)

		input_pass_event(dev, type, code, value);

		input_pass_event(dev, src_handler, type, code, value);

}



/**
@@ -352,7 +366,7 @@ void input_event(struct input_dev *dev, 


		spin_lock_irqsave(&dev->event_lock, flags);

		add_input_randomness(type, code, value);

		input_handle_event(dev, type, code, value);

		input_handle_event(dev, NULL, type, code, value);

		spin_unlock_irqrestore(&dev->event_lock, flags);

	}

}
@@ -382,7 +396,8 @@ void input_inject_event(struct input_handle *handle, 
		rcu_read_lock();

		grab = rcu_dereference(dev->grab);

		if (!grab || grab == handle)

			input_handle_event(dev, type, code, value);

			input_handle_event(dev, handle->handler,

					   type, code, value);

		rcu_read_unlock();



		spin_unlock_irqrestore(&dev->event_lock, flags);
@@ -595,10 +610,10 @@ static void input_dev_release_keys(struct input_dev *dev) 
		for (code = 0; code <= KEY_MAX; code++) {

			if (is_event_supported(code, dev->keybit, KEY_MAX) &&

			    __test_and_clear_bit(code, dev->key)) {

				input_pass_event(dev, EV_KEY, code, 0);

				input_pass_event(dev, NULL, EV_KEY, code, 0);

			}

		}

		input_pass_event(dev, EV_SYN, SYN_REPORT, 1);

		input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);

	}

}
@@ -873,9 +888,9 @@ int input_set_keycode(struct input_dev *dev, 
	    !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&

	    __test_and_clear_bit(old_keycode, dev->key)) {



		input_pass_event(dev, EV_KEY, old_keycode, 0);

		input_pass_event(dev, NULL, EV_KEY, old_keycode, 0);

		if (dev->sync)

			input_pass_event(dev, EV_SYN, SYN_REPORT, 1);

			input_pass_event(dev, NULL, EV_SYN, SYN_REPORT, 1);

	}



 out: