TransformerDeadlockTest.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/**
 * @test
 * @bug 8241390
 * @summary Test recursively retransforms the same class. The test hangs if
 *          a deadlock happens.
 * @requires vm.jvmti
 * @requires vm.flagless
 * @library /test/lib
 * @modules java.instrument
 * @compile TransformerDeadlockTest.java
 * @run driver TransformerDeadlockTest
 */

import jdk.test.lib.process.ProcessTools;
import jdk.test.lib.helpers.ClassFileInstaller;

import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.instrument.Instrumentation;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.ProtectionDomain;

public class TransformerDeadlockTest {

    private static String manifest = "Premain-Class: " +
                    TransformerDeadlockTest.Agent.class.getName() + "\n"
                    + "Can-Retransform-Classes: true\n"
                    + "Can-Retransform-Classes: true\n";

    private static String CP = System.getProperty("test.classes");

    public static void main(String args[]) throws Throwable {
        String agentJar = buildAgent();
        ProcessTools.executeProcess(
                ProcessTools.createJavaProcessBuilder(
                        "-javaagent:" + agentJar,
                        TransformerDeadlockTest.Agent.class.getName())
        ).shouldHaveExitValue(0);
    }

    private static String buildAgent() throws Exception {
        Path jar = Files.createTempFile(Paths.get("."), null, ".jar");
        String jarPath = jar.toAbsolutePath().toString();
        ClassFileInstaller.writeJar(jarPath,
                ClassFileInstaller.Manifest.fromString(manifest),
                TransformerDeadlockTest.class.getName());
        return jarPath;
    }

    public static class Agent implements ClassFileTransformer {
        private static Instrumentation instrumentation;

        public static void premain(String agentArgs, Instrumentation inst) {
            instrumentation = inst;
        }

        @Override
        public byte[] transform(
                ClassLoader loader,
                String className,
                Class<?> classBeingRedefined,
                ProtectionDomain protectionDomain,
                byte[] classfileBuffer)
                throws IllegalClassFormatException {

            if (!TransformerDeadlockTest.class.getName().replace(".", "/").equals(className)) {
                return null;
            }
            invokeRetransform();
            return classfileBuffer;

        }

        public static void main(String[] args) throws Exception {
            instrumentation.addTransformer(new TransformerDeadlockTest.Agent(), true);

            try {
                instrumentation.retransformClasses(TransformerDeadlockTest.class);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }

        private static void invokeRetransform() {
            try {
                instrumentation.retransformClasses(TransformerDeadlockTest.class);
            } catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
            }
        }
    }
}