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Commit b7ba0d93 authored by Biswarup Pal's avatar Biswarup Pal Committed by Todd Kjos
Browse files

FROMGIT: Input: uinput - allow injecting event times 

Currently, uinput doesn't use the input_set_timestamp API, so any
event injected using uinput is not accurately timestamped in terms of
measuring when the actual event happened. Hence, call the
input_set_timestamp API from uinput in order to provide a more
accurate sense of time for the event. Propagate only the timestamps
which are a) positive, b) within a pre-defined offset (10 secs) from
the current time, and c) not in the future.

Bug: 271946580
Bug: 277040837
Change-Id: I928be61d0114b78e2098995ee49eeb0376bef2a3
(cherry picked from commit 3a2df60200a03f78173f1fd831aa54c08464dcde
https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git

 master)
Signed-off-by: default avatarBiswarup Pal <biswarupp@google.com>
Reviewed-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: default avatarSiarhei Vishniakou <svv@google.com>
Link: https://lore.kernel.org/r/20230427000152.1407471-1-biswarupp@google.com


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
(cherry picked from commit ee1f5fc55cc7bf1bca78edbb8a1f9d989d4ea03e)
parent 0acbae5b

drivers/input/misc/uinput.c

+34 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#define UINPUT_NAME		"uinput"

#define UINPUT_BUFFER_SIZE	16

#define UINPUT_NUM_REQUESTS	16

#define UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS 10



enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };
@@ -569,11 +570,40 @@ static int uinput_setup_device_legacy(struct uinput_device *udev, 
	return retval;

}



/*

 * Returns true if the given timestamp is valid (i.e., if all the following

 * conditions are satisfied), false otherwise.

 * 1) given timestamp is positive

 * 2) it's within the allowed offset before the current time

 * 3) it's not in the future

 */

static bool is_valid_timestamp(const ktime_t timestamp)

{

	ktime_t zero_time;

	ktime_t current_time;

	ktime_t min_time;

	ktime_t offset;



	zero_time = ktime_set(0, 0);

	if (ktime_compare(zero_time, timestamp) >= 0)

		return false;



	current_time = ktime_get();

	offset = ktime_set(UINPUT_TIMESTAMP_ALLOWED_OFFSET_SECS, 0);

	min_time = ktime_sub(current_time, offset);



	if (ktime_after(min_time, timestamp) || ktime_after(timestamp, current_time))

		return false;



	return true;

}



static ssize_t uinput_inject_events(struct uinput_device *udev,

				    const char __user *buffer, size_t count)

{

	struct input_event ev;

	size_t bytes = 0;

	ktime_t timestamp;



	if (count != 0 && count < input_event_size())

		return -EINVAL;
@@ -588,6 +618,10 @@ static ssize_t uinput_inject_events(struct uinput_device *udev, 
		if (input_event_from_user(buffer + bytes, &ev))

			return -EFAULT;



		timestamp = ktime_set(ev.input_event_sec, ev.input_event_usec * NSEC_PER_USEC);

		if (is_valid_timestamp(timestamp))

			input_set_timestamp(udev->dev, timestamp);



		input_event(udev->dev, ev.type, ev.code, ev.value);

		bytes += input_event_size();

		cond_resched();