Add test for setOverrideFrameRate

- Create test to verify the API call in SurfaceComposerClient
- Create test to verify frame rate override DisplayEventReceiver events
are correctly received
- Add permission AID_ROOT to setOverrideFrameRate

Bug: b/204322816
Test: atest Surfaceflinger_test
Change-Id: I5b1782fcb7fc4896139ad56fcaee61853480f153

3 files changed, 106 insertions, 1 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 73a5f58ba7..5ca75d55de 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -5520,7 +5520,13 @@ status_t SurfaceFlinger::CheckTransactCodeCredentials(uint32_t code) {
             }
             return PERMISSION_DENIED;
         }
-        case SET_OVERRIDE_FRAME_RATE:
+        case SET_OVERRIDE_FRAME_RATE: {
+            const int uid = IPCThreadState::self()->getCallingUid();
+            if (uid == AID_ROOT || uid == AID_SYSTEM) {
+                return OK;
+            }
+            return PERMISSION_DENIED;
+        }
         case ON_PULL_ATOM: {
             const int uid = IPCThreadState::self()->getCallingUid();
             if (uid == AID_SYSTEM) {
diff --git a/services/surfaceflinger/tests/Android.bp b/services/surfaceflinger/tests/Android.bp
index 7b86229556..c5c0c3f788 100644
--- a/services/surfaceflinger/tests/Android.bp
+++ b/services/surfaceflinger/tests/Android.bp
@@ -47,6 +47,7 @@ cc_test {
         "ReleaseBufferCallback_test.cpp",
         "ScreenCapture_test.cpp",
         "SetFrameRate_test.cpp",
+        "SetFrameRateOverride_test.cpp",
         "SetGeometry_test.cpp",
         "Stress_test.cpp",
         "SurfaceInterceptor_test.cpp",
diff --git a/services/surfaceflinger/tests/SetFrameRateOverride_test.cpp b/services/surfaceflinger/tests/SetFrameRateOverride_test.cpp
new file mode 100644
index 0000000000..4efec7738a
--- /dev/null
+++ b/services/surfaceflinger/tests/SetFrameRateOverride_test.cpp
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+#include <gui/DisplayEventReceiver.h>
+#include <gui/ISurfaceComposer.h>
+#include <gui/SurfaceComposerClient.h>
+#include <sys/epoll.h>
+#include <algorithm>
+
+namespace android {
+namespace {
+using FrameRateOverride = DisplayEventReceiver::Event::FrameRateOverride;
+
+class SetFrameRateOverrideTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        const ISurfaceComposer::VsyncSource vsyncSource = ISurfaceComposer::eVsyncSourceApp;
+        const ISurfaceComposer::EventRegistrationFlags eventRegistration = {
+                ISurfaceComposer::EventRegistration::frameRateOverride};
+
+        mDisplayEventReceiver =
+                std::make_unique<DisplayEventReceiver>(vsyncSource, eventRegistration);
+        EXPECT_EQ(NO_ERROR, mDisplayEventReceiver->initCheck());
+
+        mEpollFd = epoll_create1(EPOLL_CLOEXEC);
+        EXPECT_GT(mEpollFd, 1);
+
+        epoll_event event;
+        event.events = EPOLLIN;
+        EXPECT_EQ(0, epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mDisplayEventReceiver->getFd(), &event));
+    }
+
+    void TearDown() override { close(mEpollFd); }
+
+    void setFrameRateAndListenEvents(uid_t uid, float frameRate) {
+        status_t ret = SurfaceComposerClient::setOverrideFrameRate(uid, frameRate);
+        ASSERT_EQ(NO_ERROR, ret);
+
+        DisplayEventReceiver::Event event;
+        bool isOverrideFlushReceived = false;
+        mFrameRateOverrides.clear();
+
+        epoll_event epollEvent;
+        while (epoll_wait(mEpollFd, &epollEvent, 1, 1000) > 0) {
+            while (mDisplayEventReceiver->getEvents(&event, 1) > 0) {
+                if (event.header.type == DisplayEventReceiver::DISPLAY_EVENT_FRAME_RATE_OVERRIDE) {
+                    mFrameRateOverrides.emplace_back(event.frameRateOverride);
+                }
+                if (event.header.type ==
+                    DisplayEventReceiver::DISPLAY_EVENT_FRAME_RATE_OVERRIDE_FLUSH) {
+                    isOverrideFlushReceived = true;
+                }
+            }
+
+            if (isOverrideFlushReceived) break;
+        }
+    }
+
+    std::unique_ptr<DisplayEventReceiver> mDisplayEventReceiver;
+    std::vector<FrameRateOverride> mFrameRateOverrides;
+
+    int mEpollFd;
+};
+
+TEST_F(SetFrameRateOverrideTest, SetFrameRateOverrideCall) {
+    uid_t uid = getuid();
+    float frameRate = 30.0f;
+    setFrameRateAndListenEvents(uid, frameRate);
+    // check if the frame rate override we set exists
+    ASSERT_TRUE(std::find_if(mFrameRateOverrides.begin(), mFrameRateOverrides.end(),
+                             [uid = uid, frameRate = frameRate](auto i) {
+                                 return uid == i.uid && frameRate == i.frameRateHz;
+                             }) != mFrameRateOverrides.end());
+
+    // test removing frame rate override
+    frameRate = 0.0f;
+    setFrameRateAndListenEvents(uid, frameRate);
+    ASSERT_TRUE(std::find_if(mFrameRateOverrides.begin(), mFrameRateOverrides.end(),
+                             [uid = uid, frameRate = frameRate](auto i) {
+                                 return uid == i.uid && frameRate == i.frameRateHz;
+                             }) == mFrameRateOverrides.end());
+}
+} // namespace
+} // namespace android