commit af91a91c5cce1263895ee804e961975ad7aab3a2
author Anh Pham <anhph@google.com> Wed Feb 10 14:10:53 2021 +0100
committer Anh Pham <anhph@google.com> Mon Feb 15 10:46:15 2021 +0100
tree 4bd2fccba8511ec8fb7a9ea8c0abbca0d03455a2
parent 5b2a141aa6849f841196d4a7d89253a0d4849f07

Throttle sensor sampling rates at 200Hz.

Only sensors of the following types are throttled: accelerometer, gyroscope and magnetometer.

Both direct and non-direct connections are throttled, as follows:
- If the microphone toggle is on: all apps are throttled at 200Hz, regardless of their targetSDK.
- If the microphone toggle is off:
    + If apps target SDK <= R, no throttling.
    + If apps target SDK >= S and has the HIGH_SAMPLING_RATE_SENSORS permission, no throttling.
    + If apps target SDK >= S and does not have the HIGH_SAMPLING_RATE_SENSORS permission:
        + Sampling rates are throttled at 200 Hz.
        + If run in debug mode, a SecurityException is thrown.

Test: atest CtsSensorTestCases CtsSensorRatePermissionTestCases
Bug: 136069189
Change-Id: Idd3ba874eee34859b3f090af59def0a939688c07

services/sensorservice/SensorEventConnection.cpp

diff --git a/services/sensorservice/SensorEventConnection.cpp b/services/sensorservice/SensorEventConnection.cpp
index 6810c1b7..90e33a9 100644
--- a/services/sensorservice/SensorEventConnection.cpp
+++ b/services/sensorservice/SensorEventConnection.cpp
@@ -44,6 +44,7 @@
       mCacheSize(0), mMaxCacheSize(0), mTimeOfLastEventDrop(0), mEventsDropped(0),
       mPackageName(packageName), mOpPackageName(opPackageName), mTargetSdk(kTargetSdkUnknown),
       mDestroyed(false) {
+    mIsRateCappedBasedOnPermission = mService->isRateCappedBasedOnPermission(mOpPackageName);
     mChannel = new BitTube(mService->mSocketBufferSize);
 #if DEBUG_CONNECTIONS
     mEventsReceived = mEventsSentFromCache = mEventsSent = 0;
@@ -684,6 +685,21 @@
 
     status_t err;
     if (enabled) {
+        bool isSensorCapped = false;
+        sp<SensorInterface> si = mService->getSensorInterfaceFromHandle(handle);
+        if (si != nullptr) {
+            const Sensor& s = si->getSensor();
+            if (mService->isSensorInCappedSet(s.getType())) {
+                isSensorCapped = true;
+            }
+        }
+        if (isSensorCapped) {
+            err = mService->adjustSamplingPeriodBasedOnMicAndPermission(&samplingPeriodNs,
+                                String16(mOpPackageName));
+            if (err != OK) {
+                return err;
+            }
+        }
         err = mService->enable(this, handle, samplingPeriodNs, maxBatchReportLatencyNs,
                                reservedFlags, mOpPackageName);
 
@@ -693,14 +709,27 @@
     return err;
 }
 
-status_t SensorService::SensorEventConnection::setEventRate(
-        int handle, nsecs_t samplingPeriodNs)
-{
+status_t SensorService::SensorEventConnection::setEventRate(int handle, nsecs_t samplingPeriodNs) {
     if (mDestroyed) {
         android_errorWriteLog(0x534e4554, "168211968");
         return DEAD_OBJECT;
     }
 
+    bool isSensorCapped = false;
+    sp<SensorInterface> si = mService->getSensorInterfaceFromHandle(handle);
+    if (si != nullptr) {
+        const Sensor& s = si->getSensor();
+        if (mService->isSensorInCappedSet(s.getType())) {
+            isSensorCapped = true;
+        }
+    }
+    if (isSensorCapped) {
+        status_t err = mService->adjustSamplingPeriodBasedOnMicAndPermission(&samplingPeriodNs,
+                            String16(mOpPackageName));
+        if (err != OK) {
+            return err;
+        }
+    }
     return mService->setEventRate(this, handle, samplingPeriodNs, mOpPackageName);
 }