| /* |
| * 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.hadoop.service.launcher; |
| |
| import java.util.concurrent.atomic.AtomicInteger; |
| |
| import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| import sun.misc.Signal; |
| import sun.misc.SignalHandler; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * Handler of interrupts that relays them to a registered |
| * implementation of {@link IrqHandler.Interrupted}. |
| * |
| * This class bundles up all the compiler warnings about abuse of sun.misc |
| * interrupt handling code into one place. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| @SuppressWarnings("UseOfSunClasses") |
| public final class IrqHandler implements SignalHandler { |
| private static final Logger LOG = LoggerFactory.getLogger(IrqHandler.class); |
| |
| /** |
| * Definition of the Control-C handler name: {@value}. |
| */ |
| public static final String CONTROL_C = "INT"; |
| |
| /** |
| * Definition of default <code>kill</code> signal: {@value}. |
| */ |
| public static final String SIGTERM = "TERM"; |
| |
| /** |
| * Signal name. |
| */ |
| private final String name; |
| |
| /** |
| * Handler to relay to. |
| */ |
| private final Interrupted handler; |
| |
| /** Count of how many times a signal has been raised. */ |
| private final AtomicInteger signalCount = new AtomicInteger(0); |
| |
| /** |
| * Stored signal. |
| */ |
| private Signal signal; |
| |
| /** |
| * Create an IRQ handler bound to the specific interrupt. |
| * @param name signal name |
| * @param handler handler |
| */ |
| public IrqHandler(String name, Interrupted handler) { |
| Preconditions.checkArgument(name != null, "Null \"name\""); |
| Preconditions.checkArgument(handler != null, "Null \"handler\""); |
| this.handler = handler; |
| this.name = name; |
| } |
| |
| /** |
| * Bind to the interrupt handler. |
| * @throws IllegalArgumentException if the exception could not be set |
| */ |
| public void bind() { |
| Preconditions.checkState(signal == null, "Handler already bound"); |
| try { |
| signal = new Signal(name); |
| Signal.handle(signal, this); |
| } catch (IllegalArgumentException e) { |
| throw new IllegalArgumentException( |
| "Could not set handler for signal \"" + name + "\"." |
| + "This can happen if the JVM has the -Xrs set.", |
| e); |
| } |
| } |
| |
| /** |
| * @return the signal name. |
| */ |
| public String getName() { |
| return name; |
| } |
| |
| /** |
| * Raise the signal. |
| */ |
| public void raise() { |
| Signal.raise(signal); |
| } |
| |
| @Override |
| public String toString() { |
| return "IrqHandler for signal " + name; |
| } |
| |
| /** |
| * Handler for the JVM API for signal handling. |
| * @param s signal raised |
| */ |
| @Override |
| public void handle(Signal s) { |
| signalCount.incrementAndGet(); |
| InterruptData data = new InterruptData(s.getName(), s.getNumber()); |
| LOG.info("Interrupted: {}", data); |
| handler.interrupted(data); |
| } |
| |
| /** |
| * Get the count of how many times a signal has been raised. |
| * @return the count of signals |
| */ |
| public int getSignalCount() { |
| return signalCount.get(); |
| } |
| |
| /** |
| * Callback issues on an interrupt. |
| */ |
| public interface Interrupted { |
| |
| /** |
| * Handle an interrupt. |
| * @param interruptData data |
| */ |
| void interrupted(InterruptData interruptData); |
| } |
| |
| /** |
| * Interrupt data to pass on. |
| */ |
| public static class InterruptData { |
| private final String name; |
| private final int number; |
| |
| public InterruptData(String name, int number) { |
| this.name = name; |
| this.number = number; |
| } |
| |
| public String getName() { |
| return name; |
| } |
| |
| public int getNumber() { |
| return number; |
| } |
| |
| @Override |
| public String toString() { |
| return "signal " + name + '(' + number + ')'; |
| } |
| } |
| } |