Block access to sensors when Sensor Privacy Mode enabled

Test: manually verified sensor access based on state of sensor privacy
      mode.
Bug: 110842805

Change-Id: I4f2f2496356ff4a407e5c0cd32bc0abcf0c8b48f
diff --git a/libs/sensorprivacy/SensorPrivacyManager.cpp b/libs/sensorprivacy/SensorPrivacyManager.cpp
new file mode 100644
index 0000000..1da79a0
--- /dev/null
+++ b/libs/sensorprivacy/SensorPrivacyManager.cpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2018 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 <mutex>
+#include <unistd.h>
+
+#include <binder/Binder.h>
+#include <binder/IServiceManager.h>
+#include <sensorprivacy/SensorPrivacyManager.h>
+
+#include <utils/SystemClock.h>
+
+namespace android {
+
+SensorPrivacyManager::SensorPrivacyManager()
+{
+}
+
+sp<hardware::ISensorPrivacyManager> SensorPrivacyManager::getService()
+{
+    std::lock_guard<Mutex> scoped_lock(mLock);
+    int64_t startTime = 0;
+    sp<hardware::ISensorPrivacyManager> service = mService;
+    while (service == nullptr || !IInterface::asBinder(service)->isBinderAlive()) {
+        sp<IBinder> binder = defaultServiceManager()->checkService(String16("sensor_privacy"));
+        if (binder == nullptr) {
+            // Wait for the sensor privacy service to come back...
+            if (startTime == 0) {
+                startTime = uptimeMillis();
+                ALOGI("Waiting for sensor privacy service");
+            } else if ((uptimeMillis() - startTime) > 1000000) {
+                ALOGW("Waiting too long for sensor privacy service, giving up");
+                service = nullptr;
+                break;
+            }
+            usleep(25000);
+        } else {
+            service = interface_cast<hardware::ISensorPrivacyManager>(binder);
+            mService = service;
+        }
+    }
+    return service;
+}
+
+void SensorPrivacyManager::addSensorPrivacyListener(
+        const sp<hardware::ISensorPrivacyListener>& listener)
+{
+    sp<hardware::ISensorPrivacyManager> service = getService();
+    if (service != nullptr) {
+        service->addSensorPrivacyListener(listener);
+    }
+}
+
+void SensorPrivacyManager::removeSensorPrivacyListener(
+        const sp<hardware::ISensorPrivacyListener>& listener)
+{
+    sp<hardware::ISensorPrivacyManager> service = getService();
+    if (service != nullptr) {
+        service->removeSensorPrivacyListener(listener);
+    }
+}
+
+bool SensorPrivacyManager::isSensorPrivacyEnabled()
+{
+    sp<hardware::ISensorPrivacyManager> service = getService();
+    if (service != nullptr) {
+        bool result;
+        service->isSensorPrivacyEnabled(&result);
+        return result;
+    }
+    // if the SensorPrivacyManager is not available then assume sensor privacy is disabled
+    return false;
+}
+
+}; // namespace android