Add system service for accessing SystemConfig

Add SystemConfigService and associated AIDLs and permissions for
accessing SystemConfig. The service returns values obtained from a
static instance of com.android.server.SystemConfig.

Bug: 143112379
Test: atest SystemConfigTest
Change-Id: I1a863ae9f53db21d698376008e5b1da83309b141

services/java/com/android/server/SystemConfigService.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+package com.android.server;
+
+import android.Manifest;
+import android.content.Context;
+import android.os.ISystemConfig;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Service class that runs inside the system_server process to handle queries to
+ * {@link com.android.server.SystemConfig}.
+ * @hide
+ */
+public class SystemConfigService extends SystemService {
+    private final Context mContext;
+
+    private final ISystemConfig.Stub mInterface = new ISystemConfig.Stub() {
+        @Override
+        public List<String> getDisabledUntilUsedPreinstalledCarrierApps() {
+            mContext.enforceCallingOrSelfPermission(Manifest.permission.READ_CARRIER_APP_INFO,
+                    "getDisabledUntilUsedPreInstalledCarrierApps requires READ_CARRIER_APP_INFO");
+            return new ArrayList<>(
+                    SystemConfig.getInstance().getDisabledUntilUsedPreinstalledCarrierApps());
+        }
+
+        @Override
+        public Map getDisabledUntilUsedPreinstalledCarrierAssociatedApps() {
+            mContext.enforceCallingOrSelfPermission(Manifest.permission.READ_CARRIER_APP_INFO,
+                    "getDisabledUntilUsedPreInstalledCarrierAssociatedApps requires"
+                            + " READ_CARRIER_APP_INFO");
+            return SystemConfig.getInstance()
+                    .getDisabledUntilUsedPreinstalledCarrierAssociatedApps();
+        }
+    };
+
+    public SystemConfigService(Context context) {
+        super(context);
+        mContext = context;
+    }
+
+    @Override
+    public void onStart() {
+        publishBinderService(Context.SYSTEM_CONFIG_SERVICE, mInterface);
+    }
+}