content: /**
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.hive.service.auth;
  
  import java.security.AccessControlContext;
  import java.security.AccessController;
  import java.security.PrivilegedActionException;
  import java.security.PrivilegedExceptionAction;
  import javax.security.auth.Subject;
  
  import org.apache.hadoop.hive.thrift.TFilterTransport;
  import org.apache.thrift.transport.TTransport;
  import org.apache.thrift.transport.TTransportException;
  
  /**
   * This is used on the client side, where the API explicitly opens a transport to
   * the server using the Subject.doAs().
   */
  public class TSubjectAssumingTransport extends TFilterTransport {
  
    public TSubjectAssumingTransport(TTransport wrapped) {
      super(wrapped);
    }
  
    @Override
    public void open() throws TTransportException {
      try {
        AccessControlContext context = AccessController.getContext();
        Subject subject = Subject.getSubject(context);
        Subject.doAs(subject, new PrivilegedExceptionAction<Void>() {
          public Void run() {
            try {
              wrapped.open();
            } catch (TTransportException tte) {
              // Wrap the transport exception in an RTE, since Subject.doAs() then goes
              // and unwraps this for us out of the doAs block. We then unwrap one
              // more time in our catch clause to get back the TTE. (ugh)
              throw new RuntimeException(tte);
            }
            return null;
          }
        });
      } catch (PrivilegedActionException ioe) {
        throw new RuntimeException("Received an ioe we never threw!", ioe);
      } catch (RuntimeException rte) {
        if (rte.getCause() instanceof TTransportException) {
          throw (TTransportException) rte.getCause();
        } else {
          throw rte;
        }
      }
    }
  
  }
  