content: /*
   * Copyright (C) 2016 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.os;
  
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.content.Context;
  import android.os.Build;
  import android.os.IDeviceIdentifiersPolicyService;
  import android.os.RemoteException;
  import android.os.SystemProperties;
  
  import com.android.internal.telephony.TelephonyPermissions;
  import com.android.server.SystemService;
  
  /**
   * This service defines the policy for accessing device identifiers.
   */
  public final class DeviceIdentifiersPolicyService extends SystemService {
      public DeviceIdentifiersPolicyService(Context context) {
          super(context);
      }
  
      @Override
      public void onStart() {
          publishBinderService(Context.DEVICE_IDENTIFIERS_SERVICE,
                  new DeviceIdentifiersPolicy(getContext()));
      }
  
      private static final class DeviceIdentifiersPolicy
              extends IDeviceIdentifiersPolicyService.Stub {
          private final @NonNull Context mContext;
  
          public DeviceIdentifiersPolicy(Context context) {
              mContext = context;
          }
  
          @Override
          public @Nullable String getSerial() throws RemoteException {
              // Since this invocation is on the server side a null value is used for the
              // callingPackage as the server's package name (typically android) should not be used
              // for any device / profile owner checks. The majority of requests for the serial number
              // should use the getSerialForPackage method with the calling package specified.
              if (!TelephonyPermissions.checkCallingOrSelfReadDeviceIdentifiers(mContext,
                      /* callingPackage */ null, "getSerial")) {
                  return Build.UNKNOWN;
              }
              return SystemProperties.get("ro.serialno", Build.UNKNOWN);
          }
  
          @Override
          public @Nullable String getSerialForPackage(String callingPackage) throws RemoteException {
              if (!TelephonyPermissions.checkCallingOrSelfReadDeviceIdentifiers(mContext,
                      callingPackage, "getSerial")) {
                  return Build.UNKNOWN;
              }
              return SystemProperties.get("ro.serialno", Build.UNKNOWN);
          }
      }
  }
  