mirror of
https://github.com/ReaJason/MemShellParty.git
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932 lines
34 KiB
Java
932 lines
34 KiB
Java
/*
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* Copyright 2014 - Present Rafael Winterhalter
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.io.File;
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import java.io.IOException;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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import java.net.MalformedURLException;
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import java.net.URISyntaxException;
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import java.net.URL;
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import java.net.URLClassLoader;
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import java.security.CodeSource;
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import java.security.PrivilegedAction;
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import java.security.ProtectionDomain;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collections;
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import java.util.List;
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/**
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* Copy from <a href="https://github.com/raphw/byte-buddy/blob/master/byte-buddy-agent">Byte Buddy</a>
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*/
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public class Attacher {
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/**
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* Representation of the bootstrap {@link java.lang.ClassLoader}.
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*/
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private static final ClassLoader BOOTSTRAP_CLASS_LOADER = null;
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/**
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* The character that is used to mark the beginning of the argument to the agent.
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*/
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private static final String AGENT_ARGUMENT_SEPARATOR = "=";
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/**
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* The agent provides only {@code static} utility methods and should not be instantiated.
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*/
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private Attacher() {
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throw new UnsupportedOperationException("This class is a utility class and not supposed to be instantiated");
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}
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/**
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* <p>
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* Attaches the given agent Jar on the target process which must be a virtual machine process. The default attachment provider
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* is used for applying the attachment. This operation blocks until the attachment is complete. If the current VM does not supply
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* any known form of attachment to a remote VM, an {@link IllegalStateException} is thrown. The agent is not provided an argument.
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* </p>
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* <p>
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* <b>Important</b>: It is only possible to attach to processes that are executed by the same operating system user.
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* </p>
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*
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* @param agentJar The agent jar file.
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* @param processId The target process id.
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*/
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public static void attach(File agentJar, String processId) {
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attach(agentJar, processId, null);
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}
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public static void attach(String processId) {
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attach(trySelfResolve(), processId, null);
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}
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/**
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* <p>
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* Attaches the given agent Jar on the target process which must be a virtual machine process. The default attachment provider
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* is used for applying the attachment. This operation blocks until the attachment is complete. If the current VM does not supply
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* any known form of attachment to a remote VM, an {@link IllegalStateException} is thrown.
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* </p>
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* <p>
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* <b>Important</b>: It is only possible to attach to processes that are executed by the same operating system user.
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* </p>
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*
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* @param agentJar The agent jar file.
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* @param processId The target process id.
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* @param argument The argument to provide to the agent.
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*/
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public static void attach(File agentJar, String processId, String argument) {
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install(processId, argument, new AgentProvider.ForExistingAgent(agentJar));
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}
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/**
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* Installs a Java agent on a target VM.
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*
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* @param processId The process id of the target JVM process.
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* @param argument The argument to provide to the agent.
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* @param agentProvider The agent provider for the agent jar or library.
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*/
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private static void install(String processId, String argument, AgentProvider agentProvider) {
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AttachmentProvider.Accessor attachmentAccessor = AttachmentProvider.DEFAULT.attempt();
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if (!attachmentAccessor.isAvailable()) {
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throw new IllegalStateException("No compatible attachment provider is available");
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}
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try {
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Class<?> virtualMachineType = attachmentAccessor.getVirtualMachineType();
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String agent = agentProvider.resolve().getAbsolutePath();
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Object virtualMachineInstance = virtualMachineType
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.getMethod("attach", String.class)
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.invoke(null, processId);
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try {
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virtualMachineType
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.getMethod("loadAgent", String.class, String.class)
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.invoke(virtualMachineInstance, agent, argument);
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} finally {
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virtualMachineType
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.getMethod("detach")
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.invoke(virtualMachineInstance);
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}
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} catch (RuntimeException exception) {
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throw exception;
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} catch (Exception exception) {
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throw new IllegalStateException("Error during attachment using: " + AttachmentProvider.DEFAULT, exception);
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}
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}
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/**
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* Attempts to resolve the location of the {@link Attacher} class for a self-attachment. Doing so avoids the creation of a temporary jar file.
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*
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* @return The self-resolved jar file or {@code null} if the jar file cannot be located.
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*/
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private static File trySelfResolve() {
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try {
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ProtectionDomain protectionDomain = Attacher.class.getProtectionDomain();
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if (protectionDomain == null) {
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return null;
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}
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CodeSource codeSource = protectionDomain.getCodeSource();
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if (codeSource == null) {
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return null;
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}
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URL location = codeSource.getLocation();
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if (!location.getProtocol().equals("file")) {
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return null;
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}
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try {
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File file = new File(location.toURI());
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if (file.getPath().contains(AGENT_ARGUMENT_SEPARATOR)) {
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return null;
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}
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return file;
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} catch (URISyntaxException ignored) {
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return new File(location.getPath());
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}
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} catch (Exception ignored) {
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return null;
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}
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}
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/**
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* An attachment provider is responsible for making the Java attachment API available.
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*/
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public interface AttachmentProvider {
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/**
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* The default attachment provider to be used.
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*/
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AttachmentProvider DEFAULT = new Compound(ForModularizedVm.INSTANCE,
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ForJ9Vm.INSTANCE,
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ForStandardToolsJarVm.JVM_ROOT,
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ForStandardToolsJarVm.JDK_ROOT,
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ForStandardToolsJarVm.MACINTOSH,
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ForUserDefinedToolsJar.INSTANCE,
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ForEmulatedAttachment.INSTANCE);
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/**
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* Attempts the creation of an accessor for a specific JVM's attachment API.
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*
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* @return The accessor this attachment provider can supply for the currently running JVM.
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*/
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Accessor attempt();
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/**
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* An accessor for a JVM's attachment API.
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*/
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interface Accessor {
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/**
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* The name of the {@code VirtualMachine} class on any OpenJDK or Oracle JDK implementation.
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*/
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String VIRTUAL_MACHINE_TYPE_NAME = "com.sun.tools.attach.VirtualMachine";
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/**
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* The name of the {@code VirtualMachine} class on IBM J9 VMs.
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*/
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String VIRTUAL_MACHINE_TYPE_NAME_J9 = "com.ibm.tools.attach.VirtualMachine";
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/**
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* Determines if this accessor is applicable for the currently running JVM.
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*
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* @return {@code true} if this accessor is available.
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*/
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boolean isAvailable();
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/**
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* Returns {@code true} if this accessor prohibits attachment to the same virtual machine in Java 9 and later.
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*
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* @return {@code true} if this accessor prohibits attachment to the same virtual machine in Java 9 and later.
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*/
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boolean isExternalAttachmentRequired();
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/**
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* Returns a {@code VirtualMachine} class. This method must only be called for available accessors.
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*
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* @return The virtual machine type.
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*/
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Class<?> getVirtualMachineType();
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/**
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* Returns a description of a virtual machine class for an external attachment.
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*
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* @return A description of the external attachment.
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*/
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ExternalAttachment getExternalAttachment();
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/**
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* A canonical implementation of an unavailable accessor.
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*/
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enum Unavailable implements Accessor {
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/**
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* The singleton instance.
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*/
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INSTANCE;
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/**
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* {@inheritDoc}
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*/
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public boolean isAvailable() {
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return false;
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}
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/**
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* {@inheritDoc}
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*/
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public boolean isExternalAttachmentRequired() {
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throw new IllegalStateException("Cannot read the virtual machine type for an unavailable accessor");
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}
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/**
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* {@inheritDoc}
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*/
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public Class<?> getVirtualMachineType() {
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throw new IllegalStateException("Cannot read the virtual machine type for an unavailable accessor");
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}
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/**
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* {@inheritDoc}
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*/
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public ExternalAttachment getExternalAttachment() {
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throw new IllegalStateException("Cannot read the virtual machine type for an unavailable accessor");
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}
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}
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/**
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* Describes an external attachment to a Java virtual machine.
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*/
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class ExternalAttachment {
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/**
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* The fully-qualified binary name of the virtual machine type.
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*/
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private final String virtualMachineType;
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/**
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* The class path elements required for loading the supplied virtual machine type.
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*/
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private final List<File> classPath;
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/**
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* Creates an external attachment.
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*
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* @param virtualMachineType The fully-qualified binary name of the virtual machine type.
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* @param classPath The class path elements required for loading the supplied virtual machine type.
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*/
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public ExternalAttachment(String virtualMachineType, List<File> classPath) {
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this.virtualMachineType = virtualMachineType;
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this.classPath = classPath;
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}
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/**
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* Returns the fully-qualified binary name of the virtual machine type.
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*
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* @return The fully-qualified binary name of the virtual machine type.
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*/
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public String getVirtualMachineType() {
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return virtualMachineType;
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}
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/**
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* Returns the class path elements required for loading the supplied virtual machine type.
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*
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* @return The class path elements required for loading the supplied virtual machine type.
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*/
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public List<File> getClassPath() {
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return classPath;
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}
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}
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/**
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* A simple implementation of an accessible accessor.
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*/
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abstract class Simple implements Accessor {
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/**
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* A {@code VirtualMachine} class.
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*/
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protected final Class<?> virtualMachineType;
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/**
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* Creates a new simple accessor.
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*
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* @param virtualMachineType A {@code VirtualMachine} class.
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*/
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protected Simple(Class<?> virtualMachineType) {
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this.virtualMachineType = virtualMachineType;
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}
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/**
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* <p>
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* Creates an accessor by reading the process id from the JMX runtime bean and by attempting
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* to load the {@code com.sun.tools.attach.VirtualMachine} class from the provided class loader.
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* </p>
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* <p>
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* This accessor is supposed to work on any implementation of the OpenJDK or Oracle JDK.
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* </p>
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*
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* @param classLoader A class loader that is capable of loading the virtual machine type.
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* @param classPath The class path required to load the virtual machine class.
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* @return An appropriate accessor.
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*/
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public static Accessor of(ClassLoader classLoader, File... classPath) {
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try {
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return new Simple.WithExternalAttachment(Class.forName(VIRTUAL_MACHINE_TYPE_NAME,
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false,
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classLoader), Arrays.asList(classPath));
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} catch (ClassNotFoundException ignored) {
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return Unavailable.INSTANCE;
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}
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}
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/**
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* <p>
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* Creates an accessor by reading the process id from the JMX runtime bean and by attempting
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* to load the {@code com.ibm.tools.attach.VirtualMachine} class from the provided class loader.
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* </p>
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* <p>
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* This accessor is supposed to work on any implementation of IBM's J9.
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* </p>
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*
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* @return An appropriate accessor.
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*/
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public static Accessor ofJ9() {
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try {
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return new Simple.WithExternalAttachment(ClassLoader.getSystemClassLoader().loadClass(VIRTUAL_MACHINE_TYPE_NAME_J9),
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Collections.<File>emptyList());
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} catch (ClassNotFoundException ignored) {
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return Unavailable.INSTANCE;
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}
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}
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/**
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* {@inheritDoc}
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*/
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public boolean isAvailable() {
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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public Class<?> getVirtualMachineType() {
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return virtualMachineType;
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}
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/**
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* A simple implementation of an accessible accessor that allows for external attachment.
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*/
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protected static class WithExternalAttachment extends Simple {
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/**
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* The class path required for loading the virtual machine type.
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*/
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private final List<File> classPath;
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/**
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* Creates a new simple accessor that allows for external attachment.
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*
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* @param virtualMachineType The {@code com.sun.tools.attach.VirtualMachine} class.
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* @param classPath The class path required for loading the virtual machine type.
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*/
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public WithExternalAttachment(Class<?> virtualMachineType, List<File> classPath) {
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super(virtualMachineType);
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this.classPath = classPath;
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}
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/**
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* {@inheritDoc}
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*/
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public boolean isExternalAttachmentRequired() {
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return true;
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}
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/**
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* {@inheritDoc}
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*/
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public ExternalAttachment getExternalAttachment() {
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return new ExternalAttachment(virtualMachineType.getName(), classPath);
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}
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}
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/**
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* A simple implementation of an accessible accessor that attaches using a virtual machine emulation that does not require external attachment.
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*/
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protected static class WithDirectAttachment extends Simple {
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/**
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* Creates a new simple accessor that implements direct attachment.
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*
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* @param virtualMachineType A {@code VirtualMachine} class.
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*/
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public WithDirectAttachment(Class<?> virtualMachineType) {
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super(virtualMachineType);
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}
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/**
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* {@inheritDoc}
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*/
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public boolean isExternalAttachmentRequired() {
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return false;
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}
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/**
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* {@inheritDoc}
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*/
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public ExternalAttachment getExternalAttachment() {
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throw new IllegalStateException("Cannot apply external attachment");
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}
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}
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}
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}
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/**
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* An attachment provider that locates the attach API directly from the system class loader, as possible since
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* introducing the Java module system via the {@code jdk.attach} module.
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*/
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enum ForModularizedVm implements AttachmentProvider {
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/**
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* The singleton instance.
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*/
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INSTANCE;
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/**
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* {@inheritDoc}
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*/
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public Accessor attempt() {
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return Accessor.Simple.of(ClassLoader.getSystemClassLoader());
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}
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}
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/**
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* An attachment provider that locates the attach API directly from the system class loader expecting
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* an IBM J9 VM.
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*/
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enum ForJ9Vm implements AttachmentProvider {
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/**
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* The singleton instance.
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*/
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INSTANCE;
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/**
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* {@inheritDoc}
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*/
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public Accessor attempt() {
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return Accessor.Simple.ofJ9();
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}
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}
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/**
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* An attachment provider that is dependant on the existence of a <i>tools.jar</i> file on the local
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* file system.
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*/
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enum ForStandardToolsJarVm implements AttachmentProvider {
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/**
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* An attachment provider that locates the <i>tools.jar</i> from a Java home directory.
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*/
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JVM_ROOT("../lib/tools.jar"),
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/**
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* An attachment provider that locates the <i>tools.jar</i> from a Java installation directory.
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* In practice, several virtual machines do not return the JRE's location for the
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* <i>java.home</i> property against the property's specification.
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*/
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JDK_ROOT("lib/tools.jar"),
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/**
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* An attachment provider that locates the <i>tools.jar</i> as it is set for several JVM
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* installations on Apple Macintosh computers.
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*/
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MACINTOSH("../Classes/classes.jar");
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|
|
/**
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* The Java home system property.
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*/
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private static final String JAVA_HOME_PROPERTY = "java.home";
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|
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/**
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* The path to the <i>tools.jar</i> file, starting from the Java home directory.
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*/
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private final String toolsJarPath;
|
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|
|
/**
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|
* Creates a new attachment provider that loads the virtual machine class from the <i>tools.jar</i>.
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|
*
|
|
* @param toolsJarPath The path to the <i>tools.jar</i> file, starting from the Java home directory.
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*/
|
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ForStandardToolsJarVm(String toolsJarPath) {
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this.toolsJarPath = toolsJarPath;
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}
|
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|
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/**
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* {@inheritDoc}
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*/
|
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public Accessor attempt() {
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File toolsJar = new File(System.getProperty(JAVA_HOME_PROPERTY), toolsJarPath);
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try {
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return toolsJar.isFile() && toolsJar.canRead()
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? Accessor.Simple.of(new URLClassLoader(new URL[]{toolsJar.toURI().toURL()}, BOOTSTRAP_CLASS_LOADER), toolsJar)
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: Accessor.Unavailable.INSTANCE;
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} catch (MalformedURLException exception) {
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throw new IllegalStateException("Could not represent " + toolsJar + " as URL");
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}
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}
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}
|
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|
|
/**
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* An attachment provider that attempts to locate a {@code tools.jar} from a custom location set via a system property.
|
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*/
|
|
enum ForUserDefinedToolsJar implements AttachmentProvider {
|
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|
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/**
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* The singelton instance.
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*/
|
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INSTANCE;
|
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|
|
/**
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|
* The property being read for locating {@code tools.jar}.
|
|
*/
|
|
public static final String PROPERTY = "net.bytebuddy.agent.toolsjar";
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|
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/**
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* {@inheritDoc}
|
|
*/
|
|
public Accessor attempt() {
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String location = System.getProperty(PROPERTY);
|
|
if (location == null) {
|
|
return Accessor.Unavailable.INSTANCE;
|
|
} else {
|
|
File toolsJar = new File(location);
|
|
try {
|
|
return Accessor.Simple.of(new URLClassLoader(new URL[]{toolsJar.toURI().toURL()}, BOOTSTRAP_CLASS_LOADER), toolsJar);
|
|
} catch (MalformedURLException exception) {
|
|
throw new IllegalStateException("Could not represent " + toolsJar + " as URL");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* An attachment provider that uses Byte Buddy's attachment API emulation. To use this feature, JNA is required.
|
|
*/
|
|
enum ForEmulatedAttachment implements AttachmentProvider {
|
|
|
|
/**
|
|
* The singleton instance.
|
|
*/
|
|
INSTANCE;
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public Accessor attempt() {
|
|
try {
|
|
return new Accessor.Simple.WithDirectAttachment(VirtualMachine.Resolver.INSTANCE.get());
|
|
} catch (Throwable ignored) {
|
|
return Accessor.Unavailable.INSTANCE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* A compound attachment provider that attempts the attachment by delegation to other providers. If
|
|
* none of the providers of this compound provider is capable of providing a valid accessor, an
|
|
* non-available accessor is returned.
|
|
*/
|
|
class Compound implements AttachmentProvider {
|
|
|
|
/**
|
|
* A list of attachment providers in the order of their application.
|
|
*/
|
|
private final List<AttachmentProvider> attachmentProviders;
|
|
|
|
/**
|
|
* Creates a new compound attachment provider.
|
|
*
|
|
* @param attachmentProvider A list of attachment providers in the order of their application.
|
|
*/
|
|
public Compound(AttachmentProvider... attachmentProvider) {
|
|
this(Arrays.asList(attachmentProvider));
|
|
}
|
|
|
|
/**
|
|
* Creates a new compound attachment provider.
|
|
*
|
|
* @param attachmentProviders A list of attachment providers in the order of their application.
|
|
*/
|
|
public Compound(List<? extends AttachmentProvider> attachmentProviders) {
|
|
this.attachmentProviders = new ArrayList<AttachmentProvider>();
|
|
for (AttachmentProvider attachmentProvider : attachmentProviders) {
|
|
if (attachmentProvider instanceof Compound) {
|
|
this.attachmentProviders.addAll(((Compound) attachmentProvider).attachmentProviders);
|
|
} else {
|
|
this.attachmentProviders.add(attachmentProvider);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public Accessor attempt() {
|
|
for (AttachmentProvider attachmentProvider : attachmentProviders) {
|
|
Accessor accessor = attachmentProvider.attempt();
|
|
if (accessor.isAvailable()) {
|
|
return accessor;
|
|
}
|
|
}
|
|
return Accessor.Unavailable.INSTANCE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* A process provider is responsible for providing the process id of the current VM.
|
|
*/
|
|
public interface ProcessProvider {
|
|
|
|
/**
|
|
* Resolves a process id for the current JVM.
|
|
*
|
|
* @return The resolved process id.
|
|
*/
|
|
String resolve();
|
|
|
|
/**
|
|
* Supplies the current VM's process id.
|
|
*/
|
|
enum ForCurrentVm implements ProcessProvider {
|
|
|
|
/**
|
|
* The singleton instance.
|
|
*/
|
|
INSTANCE;
|
|
|
|
/**
|
|
* The best process provider for the current VM.
|
|
*/
|
|
private final ProcessProvider dispatcher;
|
|
|
|
/**
|
|
* Creates a process provider that supplies the current VM's process id.
|
|
*/
|
|
ForCurrentVm() {
|
|
dispatcher = ForJava9CapableVm.make();
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public String resolve() {
|
|
return dispatcher.resolve();
|
|
}
|
|
|
|
/**
|
|
* A process provider for a legacy VM that reads the process id from its JMX properties. This strategy
|
|
* is only used prior to Java 9 such that the <i>java.management</i> module never is resolved, even if
|
|
* the module system is used, as the module system was not available in any relevant JVM version.
|
|
*/
|
|
protected enum ForLegacyVm implements ProcessProvider {
|
|
|
|
/**
|
|
* The singleton instance.
|
|
*/
|
|
INSTANCE;
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public String resolve() {
|
|
String runtimeName;
|
|
try {
|
|
Method method = Class.forName("java.lang.management.ManagementFactory").getMethod("getRuntimeMXBean");
|
|
runtimeName = (String) method.getReturnType().getMethod("getName").invoke(method.invoke(null));
|
|
} catch (Exception exception) {
|
|
throw new IllegalStateException("Failed to access VM name via management factory", exception);
|
|
}
|
|
int processIdIndex = runtimeName.indexOf('@');
|
|
if (processIdIndex == -1) {
|
|
throw new IllegalStateException("Cannot extract process id from runtime management bean");
|
|
} else {
|
|
return runtimeName.substring(0, processIdIndex);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* A process provider for a Java 9 capable VM with access to the introduced process API.
|
|
*/
|
|
protected static class ForJava9CapableVm implements ProcessProvider {
|
|
|
|
/**
|
|
* The {@code java.lang.ProcessHandle#current()} method.
|
|
*/
|
|
private final Method current;
|
|
|
|
/**
|
|
* The {@code java.lang.ProcessHandle#pid()} method.
|
|
*/
|
|
private final Method pid;
|
|
|
|
/**
|
|
* Creates a new Java 9 capable dispatcher for reading the current process's id.
|
|
*
|
|
* @param current The {@code java.lang.ProcessHandle#current()} method.
|
|
* @param pid The {@code java.lang.ProcessHandle#pid()} method.
|
|
*/
|
|
protected ForJava9CapableVm(Method current, Method pid) {
|
|
this.current = current;
|
|
this.pid = pid;
|
|
}
|
|
|
|
/**
|
|
* Attempts to create a dispatcher for a Java 9 VM and falls back to a legacy dispatcher
|
|
* if this is not possible.
|
|
*
|
|
* @return A dispatcher for the current VM.
|
|
*/
|
|
public static ProcessProvider make() {
|
|
try {
|
|
return new ForJava9CapableVm(Class.forName("java.lang.ProcessHandle").getMethod("current"),
|
|
Class.forName("java.lang.ProcessHandle").getMethod("pid"));
|
|
} catch (Exception ignored) {
|
|
return ForLegacyVm.INSTANCE;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public String resolve() {
|
|
try {
|
|
return pid.invoke(current.invoke(null)).toString();
|
|
} catch (IllegalAccessException exception) {
|
|
throw new IllegalStateException("Cannot access Java 9 process API", exception);
|
|
} catch (InvocationTargetException exception) {
|
|
throw new IllegalStateException("Error when accessing Java 9 process API", exception.getTargetException());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* An agent provider is responsible for handling and providing the jar file of an agent that is being attached.
|
|
*/
|
|
protected interface AgentProvider {
|
|
|
|
/**
|
|
* Provides an agent jar file for attachment.
|
|
*
|
|
* @return The provided agent.
|
|
* @throws IOException If the agent cannot be written to disk.
|
|
*/
|
|
File resolve() throws IOException;
|
|
|
|
/**
|
|
* An agent provider that supplies an existing agent that is not deleted after attachment.
|
|
*/
|
|
class ForExistingAgent implements AgentProvider {
|
|
|
|
/**
|
|
* The supplied agent.
|
|
*/
|
|
private final File agent;
|
|
|
|
/**
|
|
* Creates an agent provider for an existing agent.
|
|
*
|
|
* @param agent The supplied agent.
|
|
*/
|
|
protected ForExistingAgent(File agent) {
|
|
this.agent = agent;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public File resolve() {
|
|
return agent;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* An attachment evaluator is responsible for deciding if an agent can be attached from the current process.
|
|
*/
|
|
protected interface AttachmentTypeEvaluator {
|
|
|
|
/**
|
|
* Checks if the current VM requires external attachment for the supplied process id.
|
|
*
|
|
* @param processId The process id of the process to which to attach.
|
|
* @return {@code true} if the current VM requires external attachment for the supplied process.
|
|
*/
|
|
boolean requiresExternalAttachment(String processId);
|
|
|
|
/**
|
|
* An installation action for creating an attachment type evaluator.
|
|
*/
|
|
enum InstallationAction implements PrivilegedAction<AttachmentTypeEvaluator> {
|
|
|
|
/**
|
|
* The singleton instance.
|
|
*/
|
|
INSTANCE;
|
|
|
|
/**
|
|
* The OpenJDK's property for specifying the legality of self-attachment.
|
|
*/
|
|
private static final String JDK_ALLOW_SELF_ATTACH = "jdk.attach.allowAttachSelf";
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public AttachmentTypeEvaluator run() {
|
|
try {
|
|
if (Boolean.getBoolean(JDK_ALLOW_SELF_ATTACH)) {
|
|
return Disabled.INSTANCE;
|
|
} else {
|
|
return new ForJava9CapableVm(Class.forName("java.lang.ProcessHandle").getMethod("current"),
|
|
Class.forName("java.lang.ProcessHandle").getMethod("pid"));
|
|
}
|
|
} catch (Exception ignored) {
|
|
return Disabled.INSTANCE;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* An attachment type evaluator that never requires external attachment.
|
|
*/
|
|
enum Disabled implements AttachmentTypeEvaluator {
|
|
|
|
/**
|
|
* The singleton instance.
|
|
*/
|
|
INSTANCE;
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public boolean requiresExternalAttachment(String processId) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* An attachment type evaluator that checks a process id against the current process id.
|
|
*/
|
|
class ForJava9CapableVm implements AttachmentTypeEvaluator {
|
|
|
|
/**
|
|
* The {@code java.lang.ProcessHandle#current()} method.
|
|
*/
|
|
private final Method current;
|
|
|
|
/**
|
|
* The {@code java.lang.ProcessHandle#pid()} method.
|
|
*/
|
|
private final Method pid;
|
|
|
|
/**
|
|
* Creates a new attachment type evaluator.
|
|
*
|
|
* @param current The {@code java.lang.ProcessHandle#current()} method.
|
|
* @param pid The {@code java.lang.ProcessHandle#pid()} method.
|
|
*/
|
|
protected ForJava9CapableVm(Method current, Method pid) {
|
|
this.current = current;
|
|
this.pid = pid;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*/
|
|
public boolean requiresExternalAttachment(String processId) {
|
|
try {
|
|
return pid.invoke(current.invoke(null)).toString().equals(processId);
|
|
} catch (IllegalAccessException exception) {
|
|
throw new IllegalStateException("Cannot access Java 9 process API", exception);
|
|
} catch (InvocationTargetException exception) {
|
|
throw new IllegalStateException("Error when accessing Java 9 process API", exception.getTargetException());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|