InputReader: Add getter API for the sysfs node path of an InputDevice

Bug: 397208968
Test: Presubmit
Flag: EXEMPT bug fix
Change-Id: I25f41f41ec1f1e47590eef21b982287caea193a6

Author: prabirmsp

services/inputflinger/include/InputReaderBase.h

@@ -443,6 +443,9 @@ class InputReaderInterface {
     /* Get the Bluetooth address of an input device, if known. */
     virtual std::optional<std::string> getBluetoothAddress(int32_t deviceId) const = 0;
 
+    /* Gets the sysfs root path for this device. Returns an empty path if there is none. */
+    virtual std::filesystem::path getSysfsRootPath(int32_t deviceId) const = 0;
+
     /* Sysfs node change reported. Recreate device if required to incorporate the new sysfs nodes */
     virtual void sysfsNodeChanged(const std::string& sysfsNodePath) = 0;
 

services/inputflinger/reader/EventHub.cpp

@@ -246,7 +246,7 @@ static nsecs_t processEventTimestamp(const struct input_event& event) {
 /**
  * Returns the sysfs root path of the input device.
  */
-static std::optional<std::filesystem::path> getSysfsRootPath(const char* devicePath) {
+static std::optional<std::filesystem::path> getSysfsRootForEvdevDevicePath(const char* devicePath) {
     std::error_code errorCode;
 
     // Stat the device path to get the major and minor number of the character file
@@ -1619,7 +1619,7 @@ void EventHub::assignDescriptorLocked(InputDeviceIdentifier& identifier) {
 std::shared_ptr<const EventHub::AssociatedDevice> EventHub::obtainAssociatedDeviceLocked(
         const std::filesystem::path& devicePath, const std::shared_ptr<PropertyMap>& config) const {
     const std::optional<std::filesystem::path> sysfsRootPathOpt =
-            getSysfsRootPath(devicePath.c_str());
+            getSysfsRootForEvdevDevicePath(devicePath.c_str());
     if (!sysfsRootPathOpt) {
         return nullptr;
     }
@@ -2666,6 +2666,18 @@ status_t EventHub::disableDevice(int32_t deviceId) {
     return device->disable();
 }
 
+std::filesystem::path EventHub::getSysfsRootPath(int32_t deviceId) const {
+    std::scoped_lock _l(mLock);
+    Device* device = getDeviceLocked(deviceId);
+    if (device == nullptr) {
+        ALOGE("Invalid device id=%" PRId32 " provided to %s", deviceId, __func__);
+        return {};
+    }
+
+    return device->associatedDevice ? device->associatedDevice->sysfsRootPath
+                                    : std::filesystem::path{};
+}
+
 // TODO(b/274755573): Shift to uevent handling on native side and remove this method
 // Currently using Java UEventObserver to trigger this which uses UEvent infrastructure that uses a
 // NETLINK socket to observe UEvents. We can create similar infrastructure on Eventhub side to
@@ -2710,6 +2722,10 @@ void EventHub::handleSysfsNodeChangeNotificationsLocked() {
         auto reloadedDevice = AssociatedDevice(dev.associatedDevice->sysfsRootPath,
                                                dev.associatedDevice->baseDevConfig);
         const bool changed = *dev.associatedDevice != reloadedDevice;
+        if (changed) {
+            ALOGI("sysfsNodeChanged: Identified change in sysfs nodes for device: %s",
+                  dev.identifier.name.c_str());
+        }
         testedDevices.emplace(dev.associatedDevice, changed);
         return changed;
     };

services/inputflinger/reader/InputDevice.cpp

@@ -136,6 +136,8 @@ void InputDevice::dump(std::string& dump, const std::string& eventHubDevStr) {
     } else {
         dump += "<none>\n";
     }
+    dump += StringPrintf(INDENT2 "SysfsRootPath:     %s\n",
+                         mSysfsRootPath.empty() ? "<none>" : mSysfsRootPath.c_str());
     dump += StringPrintf(INDENT2 "HasMic:     %s\n", toString(mHasMic));
     dump += StringPrintf(INDENT2 "Sources: %s\n",
                          inputEventSourceToString(deviceInfo.getSources()).c_str());
@@ -195,6 +197,10 @@ void InputDevice::addEmptyEventHubDevice(int32_t eventHubId) {
     DevicePair& devicePair = mDevices[eventHubId];
     devicePair.second = createMappers(*devicePair.first, readerConfig);
 
+    if (mSysfsRootPath.empty()) {
+        mSysfsRootPath = devicePair.first->getSysfsRootPath();
+    }
+
     // Must change generation to flag this device as changed
     bumpGeneration();
     return out;

services/inputflinger/reader/InputReader.cpp

@@ -917,6 +917,16 @@ bool InputReader::canDispatchToDisplay(int32_t deviceId, ui::LogicalDisplayId di
     return *associatedDisplayId == displayId;
 }
 
+std::filesystem::path InputReader::getSysfsRootPath(int32_t deviceId) const {
+    std::scoped_lock _l(mLock);
+
+    const InputDevice* device = findInputDeviceLocked(deviceId);
+    if (!device) {
+        return {};
+    }
+    return device->getSysfsRootPath();
+}
+
 void InputReader::sysfsNodeChanged(const std::string& sysfsNodePath) {
     mEventHub->sysfsNodeChanged(sysfsNodePath);
     mEventHub->wake();

services/inputflinger/reader/include/EventHub.h

@@ -399,6 +399,9 @@ class EventHubInterface {
     /* Disable an input device. Closes file descriptor to that device. */
     virtual status_t disableDevice(int32_t deviceId) = 0;
 
+    /* Gets the sysfs root path for this device. Returns an empty path if there is none. */
+    virtual std::filesystem::path getSysfsRootPath(int32_t deviceId) const = 0;
+
     /* Sysfs node changed. Reopen the Eventhub device if any new Peripheral like Light, Battery,
      * etc. is detected. */
     virtual void sysfsNodeChanged(const std::string& sysfsNodePath) = 0;
@@ -614,6 +617,8 @@ class EventHub : public EventHubInterface {
 
     status_t disableDevice(int32_t deviceId) override final;
 
+    std::filesystem::path getSysfsRootPath(int32_t deviceId) const override final;
+
     void sysfsNodeChanged(const std::string& sysfsNodePath) override final;
 
     bool setKernelWakeEnabled(int32_t deviceId, bool enabled) override final;

services/inputflinger/reader/include/InputDevice.h

@@ -81,6 +81,8 @@ class InputDevice {
 
     inline virtual KeyboardType getKeyboardType() const { return mKeyboardType; }
 
+    inline std::filesystem::path getSysfsRootPath() const { return mSysfsRootPath; }
+
     bool isEnabled();
 
     void dump(std::string& dump, const std::string& eventHubDevStr);
@@ -209,6 +211,7 @@ class InputDevice {
     bool mHasMic;
     bool mDropUntilNextSync;
     std::optional<bool> mShouldSmoothScroll;
+    std::filesystem::path mSysfsRootPath;
 
     typedef int32_t (InputMapper::*GetStateFunc)(uint32_t sourceMask, int32_t code);
     int32_t getState(uint32_t sourceMask, int32_t code, GetStateFunc getStateFunc);
@@ -471,6 +474,9 @@ class InputDeviceContext {
     inline void setKeyboardType(KeyboardType keyboardType) {
         return mDevice.setKeyboardType(keyboardType);
     }
+    inline std::filesystem::path getSysfsRootPath() const {
+        return mEventHub->getSysfsRootPath(mId);
+    }
     inline bool setKernelWakeEnabled(bool enabled) {
         return mEventHub->setKernelWakeEnabled(mId, enabled);
     }

services/inputflinger/reader/include/InputReader.h

@@ -118,6 +118,8 @@ class InputReader : public InputReaderInterface {
 
     std::optional<std::string> getBluetoothAddress(int32_t deviceId) const override;
 
+    std::filesystem::path getSysfsRootPath(int32_t deviceId) const override;
+
     void sysfsNodeChanged(const std::string& sysfsNodePath) override;
 
     DeviceId getLastUsedInputDeviceId() override;

services/inputflinger/tests/FakeEventHub.cpp

@@ -627,6 +627,14 @@ void FakeEventHub::setSysfsRootPath(int32_t deviceId, std::string sysfsRootPath)
     device->sysfsRootPath = sysfsRootPath;
 }
 
+std::filesystem::path FakeEventHub::getSysfsRootPath(int32_t deviceId) const {
+    Device* device = getDevice(deviceId);
+    if (device == nullptr) {
+        return {};
+    }
+    return device->sysfsRootPath;
+}
+
 void FakeEventHub::sysfsNodeChanged(const std::string& sysfsNodePath) {
     int32_t foundDeviceId = -1;
     Device* foundDevice = nullptr;

services/inputflinger/tests/FakeEventHub.h

@@ -222,6 +222,7 @@ class FakeEventHub : public EventHubInterface {
     std::optional<int32_t> getLightBrightness(int32_t deviceId, int32_t lightId) const override;
     std::optional<std::unordered_map<LightColor, int32_t>> getLightIntensities(
             int32_t deviceId, int32_t lightId) const override;
+    std::filesystem::path getSysfsRootPath(int32_t deviceId) const override;
     void sysfsNodeChanged(const std::string& sysfsNodePath) override;
     void dump(std::string&) const override {}
     void monitor() const override {}

services/inputflinger/tests/InputReader_test.cpp

@@ -611,8 +611,10 @@ class InputReaderTest : public testing::Test {
     }
 
     void addDevice(int32_t eventHubId, const std::string& name,
-                   ftl::Flags<InputDeviceClass> classes, const PropertyMap* configuration) {
+                   ftl::Flags<InputDeviceClass> classes, const PropertyMap* configuration,
+                   std::string sysfsRootPath = "") {
         mFakeEventHub->addDevice(eventHubId, name, classes);
+        mFakeEventHub->setSysfsRootPath(eventHubId, sysfsRootPath);
 
         if (configuration) {
             mFakeEventHub->addConfigurationMap(eventHubId, configuration);
@@ -664,6 +666,18 @@ TEST_F(InputReaderTest, PolicyGetInputDevices) {
     ASSERT_EQ(0U, inputDevices[0].getMotionRanges().size());
 }
 
+TEST_F(InputReaderTest, GetSysfsRootPath) {
+    constexpr std::string SYSFS_ROOT = "xyz";
+    ASSERT_NO_FATAL_FAILURE(
+            addDevice(1, "keyboard", InputDeviceClass::KEYBOARD, nullptr, SYSFS_ROOT));
+
+    // Should also have received a notification describing the new input device.
+    ASSERT_EQ(1U, mFakePolicy->getInputDevices().size());
+    InputDeviceInfo inputDevice = mFakePolicy->getInputDevices()[0];
+
+    ASSERT_EQ(SYSFS_ROOT, mReader->getSysfsRootPath(inputDevice.getId()).string());
+}
+
 TEST_F(InputReaderTest, InputDeviceRecreatedOnSysfsNodeChanged) {
     ASSERT_NO_FATAL_FAILURE(addDevice(1, "keyboard", InputDeviceClass::KEYBOARD, nullptr));
     mFakeEventHub->setSysfsRootPath(1, "xyz");