content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.fuse;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import sun.misc.Signal;
  import sun.misc.SignalHandler;
  
  /**
   * Respond to the kill command when in mount fuse JVM.
   * If it does not respond, the subsequent shutdown hook will not be triggered.
   */
  public class FuseSignalHandler implements SignalHandler {
    private static final Logger LOG = LoggerFactory.getLogger(FuseSignalHandler.class);
  
    /**
     * Use to umount Fuse application during stop.
     */
    private FuseUmountable mFuseUmountable;
  
    /**
     * Constructs the new {@link FuseSignalHandler}.
     * @param fuseUmountable mounted fuse application
     */
    public FuseSignalHandler(FuseUmountable fuseUmountable) {
      mFuseUmountable = fuseUmountable;
    }
  
    @Override
    public void handle(Signal signal) {
      LOG.info("Receive signal name {}, number {}, system exiting",
          signal.getName(), signal.getNumber());
      int number = signal.getNumber();
      if (number == 15) {
        try {
          mFuseUmountable.umount(false);
        } catch (Throwable t) {
          LOG.error("unable to umount fuse.", t);
          return;
        }
      }
      System.exit(0);
    }
  }
  