From 5fdbe44d033d059cc56c2803e6b4dbd8cb4e5e39 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Mon, 8 Nov 2010 21:51:25 -0800 Subject: [PATCH] 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: Dmitry Torokhov --- drivers/input/input.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/drivers/input/input.c b/drivers/input/input.c index 75bed635b98d..7f26ca6ecf75 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -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: -- 2.39.2