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 <dtor@mail.ru>
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 75bed63..7f26ca6 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -74,6 +74,7 @@
* 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 @@
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 @@
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 @@
* 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 @@
#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 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
!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: