| /* |
| * Copyright (c) 2017 SAP SE. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /** |
| * @test |
| * @bug 8173743 |
| * @requires vm.compMode != "Xcomp" |
| * @summary Failures during class definition can lead to memory leaks in metaspace |
| * @library /test/lib |
| * @run main/othervm test.DefineClass defineClass |
| * @run main/othervm test.DefineClass defineSystemClass |
| * @run main/othervm -XX:+UnlockDiagnosticVMOptions |
| -XX:+UnsyncloadClass -XX:+AllowParallelDefineClass |
| test.DefineClass defineClassParallel |
| * @run main/othervm -XX:+UnlockDiagnosticVMOptions |
| -XX:+UnsyncloadClass -XX:-AllowParallelDefineClass |
| test.DefineClass defineClassParallel |
| * @run main/othervm -XX:+UnlockDiagnosticVMOptions |
| -XX:-UnsyncloadClass -XX:+AllowParallelDefineClass |
| test.DefineClass defineClassParallel |
| * @run main/othervm -XX:+UnlockDiagnosticVMOptions |
| -XX:-UnsyncloadClass -XX:-AllowParallelDefineClass |
| test.DefineClass defineClassParallel |
| * @run main/othervm -Djdk.attach.allowAttachSelf test.DefineClass redefineClass |
| * @run main/othervm -Djdk.attach.allowAttachSelf test.DefineClass redefineClassWithError |
| * @author volker.simonis@gmail.com |
| */ |
| |
| package test; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.File; |
| import java.io.FileOutputStream; |
| import java.io.InputStream; |
| import java.lang.instrument.ClassDefinition; |
| import java.lang.instrument.Instrumentation; |
| import java.lang.management.ManagementFactory; |
| import java.util.Scanner; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.jar.Attributes; |
| import java.util.jar.JarEntry; |
| import java.util.jar.JarOutputStream; |
| import java.util.jar.Manifest; |
| |
| import javax.management.MBeanServer; |
| import javax.management.ObjectName; |
| |
| import com.sun.tools.attach.VirtualMachine; |
| |
| import jdk.test.lib.process.ProcessTools; |
| |
| public class DefineClass { |
| |
| private static Instrumentation instrumentation; |
| |
| public void getID(CountDownLatch start, CountDownLatch stop) { |
| String id = "AAAAAAAA"; |
| System.out.println(id); |
| try { |
| // Signal that we've entered the activation.. |
| start.countDown(); |
| //..and wait until we can leave it. |
| stop.await(); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| } |
| System.out.println(id); |
| return; |
| } |
| |
| private static class MyThread extends Thread { |
| private DefineClass dc; |
| private CountDownLatch start, stop; |
| |
| public MyThread(DefineClass dc, CountDownLatch start, CountDownLatch stop) { |
| this.dc = dc; |
| this.start = start; |
| this.stop = stop; |
| } |
| |
| public void run() { |
| dc.getID(start, stop); |
| } |
| } |
| |
| private static class ParallelLoadingThread extends Thread { |
| private MyParallelClassLoader pcl; |
| private CountDownLatch stop; |
| private byte[] buf; |
| |
| public ParallelLoadingThread(MyParallelClassLoader pcl, byte[] buf, CountDownLatch stop) { |
| this.pcl = pcl; |
| this.stop = stop; |
| this.buf = buf; |
| } |
| |
| public void run() { |
| try { |
| stop.await(); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| } |
| try { |
| @SuppressWarnings("unchecked") |
| Class<DefineClass> dc = (Class<DefineClass>) pcl.myDefineClass(DefineClass.class.getName(), buf, 0, buf.length); |
| } |
| catch (LinkageError jle) { |
| // Expected with a parallel capable class loader and |
| // -XX:+UnsyncloadClass or -XX:+AllowParallelDefineClass |
| pcl.incrementLinkageErrors(); |
| } |
| |
| } |
| } |
| |
| static private class MyClassLoader extends ClassLoader { |
| public Class<?> myDefineClass(String name, byte[] b, int off, int len) throws ClassFormatError { |
| return defineClass(name, b, off, len, null); |
| } |
| } |
| |
| static private class MyParallelClassLoader extends ClassLoader { |
| static { |
| System.out.println("parallelCapable : " + registerAsParallelCapable()); |
| } |
| public Class<?> myDefineClass(String name, byte[] b, int off, int len) throws ClassFormatError { |
| return defineClass(name, b, off, len, null); |
| } |
| public synchronized void incrementLinkageErrors() { |
| linkageErrors++; |
| } |
| public int getLinkageErrors() { |
| return linkageErrors; |
| } |
| private volatile int linkageErrors; |
| } |
| |
| public static void agentmain(String args, Instrumentation inst) { |
| System.out.println("Loading Java Agent."); |
| instrumentation = inst; |
| } |
| |
| |
| private static void loadInstrumentationAgent(String myName, byte[] buf) throws Exception { |
| // Create agent jar file on the fly |
| Manifest m = new Manifest(); |
| m.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0"); |
| m.getMainAttributes().put(new Attributes.Name("Agent-Class"), myName); |
| m.getMainAttributes().put(new Attributes.Name("Can-Redefine-Classes"), "true"); |
| File jarFile = File.createTempFile("agent", ".jar"); |
| jarFile.deleteOnExit(); |
| JarOutputStream jar = new JarOutputStream(new FileOutputStream(jarFile), m); |
| jar.putNextEntry(new JarEntry(myName.replace('.', '/') + ".class")); |
| jar.write(buf); |
| jar.close(); |
| String pid = Long.toString(ProcessTools.getProcessId()); |
| System.out.println("Our pid is = " + pid); |
| VirtualMachine vm = VirtualMachine.attach(pid); |
| vm.loadAgent(jarFile.getAbsolutePath()); |
| } |
| |
| private static byte[] getBytecodes(String myName) throws Exception { |
| InputStream is = DefineClass.class.getResourceAsStream(myName + ".class"); |
| ByteArrayOutputStream baos = new ByteArrayOutputStream(); |
| byte[] buf = new byte[4096]; |
| int len; |
| while ((len = is.read(buf)) != -1) baos.write(buf, 0, len); |
| buf = baos.toByteArray(); |
| System.out.println("sizeof(" + myName + ".class) == " + buf.length); |
| return buf; |
| } |
| |
| private static int getStringIndex(String needle, byte[] buf) { |
| return getStringIndex(needle, buf, 0); |
| } |
| |
| private static int getStringIndex(String needle, byte[] buf, int offset) { |
| outer: |
| for (int i = offset; i < buf.length - offset - needle.length(); i++) { |
| for (int j = 0; j < needle.length(); j++) { |
| if (buf[i + j] != (byte)needle.charAt(j)) continue outer; |
| } |
| return i; |
| } |
| return 0; |
| } |
| |
| private static void replaceString(byte[] buf, String name, int index) { |
| for (int i = index; i < index + name.length(); i++) { |
| buf[i] = (byte)name.charAt(i - index); |
| } |
| } |
| |
| private static MBeanServer mbserver = ManagementFactory.getPlatformMBeanServer(); |
| |
| private static int getClassStats(String pattern) { |
| try { |
| ObjectName diagCmd = new ObjectName("com.sun.management:type=DiagnosticCommand"); |
| |
| String result = (String)mbserver.invoke(diagCmd , "gcClassStats" , new Object[] { null }, new String[] {String[].class.getName()}); |
| int count = 0; |
| try (Scanner s = new Scanner(result)) { |
| if (s.hasNextLine()) { |
| System.out.println(s.nextLine()); |
| } |
| while (s.hasNextLine()) { |
| String l = s.nextLine(); |
| if (l.endsWith(pattern)) { |
| count++; |
| System.out.println(l); |
| } |
| } |
| } |
| return count; |
| } |
| catch (Exception e) { |
| throw new RuntimeException("Test failed because we can't read the class statistics!", e); |
| } |
| } |
| |
| private static void printClassStats(int expectedCount, boolean reportError) { |
| int count = getClassStats("DefineClass"); |
| String res = "Should have " + expectedCount + |
| " DefineClass instances and we have: " + count; |
| System.out.println(res); |
| if (reportError && count != expectedCount) { |
| throw new RuntimeException(res); |
| } |
| } |
| |
| public static final int ITERATIONS = 10; |
| |
| public static void main(String[] args) throws Exception { |
| String myName = DefineClass.class.getName(); |
| byte[] buf = getBytecodes(myName.substring(myName.lastIndexOf(".") + 1)); |
| int iterations = (args.length > 1 ? Integer.parseInt(args[1]) : ITERATIONS); |
| |
| if (args.length == 0 || "defineClass".equals(args[0])) { |
| MyClassLoader cl = new MyClassLoader(); |
| for (int i = 0; i < iterations; i++) { |
| try { |
| @SuppressWarnings("unchecked") |
| Class<DefineClass> dc = (Class<DefineClass>) cl.myDefineClass(myName, buf, 0, buf.length); |
| System.out.println(dc); |
| } |
| catch (LinkageError jle) { |
| // Can only define once! |
| if (i == 0) throw new Exception("Should succeed the first time."); |
| } |
| } |
| // We expect to have two instances of DefineClass here: the initial version in which we are |
| // executing and another version which was loaded into our own classloader 'MyClassLoader'. |
| // All the subsequent attempts to reload DefineClass into our 'MyClassLoader' should have failed. |
| printClassStats(2, false); |
| System.gc(); |
| System.out.println("System.gc()"); |
| // At least after System.gc() the failed loading attempts should leave no instances around! |
| printClassStats(2, true); |
| } |
| else if ("defineSystemClass".equals(args[0])) { |
| MyClassLoader cl = new MyClassLoader(); |
| int index = getStringIndex("test/DefineClass", buf); |
| replaceString(buf, "java/DefineClass", index); |
| while ((index = getStringIndex("Ltest/DefineClass;", buf, index + 1)) != 0) { |
| replaceString(buf, "Ljava/DefineClass;", index); |
| } |
| index = getStringIndex("test.DefineClass", buf); |
| replaceString(buf, "java.DefineClass", index); |
| |
| for (int i = 0; i < iterations; i++) { |
| try { |
| @SuppressWarnings("unchecked") |
| Class<DefineClass> dc = (Class<DefineClass>) cl.myDefineClass(null, buf, 0, buf.length); |
| throw new RuntimeException("Defining a class in the 'java' package should fail!"); |
| } |
| catch (java.lang.SecurityException jlse) { |
| // Expected, because we're not allowed to define a class in the 'java' package |
| } |
| } |
| // We expect to stay with one (the initial) instances of DefineClass. |
| // All the subsequent attempts to reload DefineClass into the 'java' package should have failed. |
| printClassStats(1, false); |
| System.gc(); |
| System.out.println("System.gc()"); |
| // At least after System.gc() the failed loading attempts should leave no instances around! |
| printClassStats(1, true); |
| } |
| else if ("defineClassParallel".equals(args[0])) { |
| MyParallelClassLoader pcl = new MyParallelClassLoader(); |
| CountDownLatch stop = new CountDownLatch(1); |
| |
| Thread[] threads = new Thread[iterations]; |
| for (int i = 0; i < iterations; i++) { |
| (threads[i] = new ParallelLoadingThread(pcl, buf, stop)).start(); |
| } |
| stop.countDown(); // start parallel class loading.. |
| // ..and wait until all threads loaded the class |
| for (int i = 0; i < iterations; i++) { |
| threads[i].join(); |
| } |
| System.out.print("Counted " + pcl.getLinkageErrors() + " LinkageErrors "); |
| System.out.println(pcl.getLinkageErrors() == 0 ? |
| "" : "(use -XX:+UnsyncloadClass and/or -XX:+AllowParallelDefineClass to avoid this)"); |
| System.gc(); |
| System.out.println("System.gc()"); |
| // After System.gc() we expect to remain with two instances: one is the initial version which is |
| // kept alive by this main method and another one in the parallel class loader. |
| printClassStats(2, true); |
| } |
| else if ("redefineClass".equals(args[0])) { |
| loadInstrumentationAgent(myName, buf); |
| int index = getStringIndex("AAAAAAAA", buf); |
| CountDownLatch stop = new CountDownLatch(1); |
| |
| Thread[] threads = new Thread[iterations]; |
| for (int i = 0; i < iterations; i++) { |
| buf[index] = (byte) ('A' + i + 1); // Change string constant in getID() which is legal in redefinition |
| instrumentation.redefineClasses(new ClassDefinition(DefineClass.class, buf)); |
| DefineClass dc = DefineClass.class.newInstance(); |
| CountDownLatch start = new CountDownLatch(1); |
| (threads[i] = new MyThread(dc, start, stop)).start(); |
| start.await(); // Wait until the new thread entered the getID() method |
| } |
| // We expect to have one instance for each redefinition because they are all kept alive by an activation |
| // plus the initial version which is kept active by this main method. |
| printClassStats(iterations + 1, false); |
| stop.countDown(); // Let all threads leave the DefineClass.getID() activation.. |
| // ..and wait until really all of them returned from DefineClass.getID() |
| for (int i = 0; i < iterations; i++) { |
| threads[i].join(); |
| } |
| System.gc(); |
| System.out.println("System.gc()"); |
| // After System.gc() we expect to remain with two instances: one is the initial version which is |
| // kept alive by this main method and another one which is the latest redefined version. |
| printClassStats(2, true); |
| } |
| else if ("redefineClassWithError".equals(args[0])) { |
| loadInstrumentationAgent(myName, buf); |
| int index = getStringIndex("getID", buf); |
| |
| for (int i = 0; i < iterations; i++) { |
| buf[index] = (byte) 'X'; // Change getID() to XetID() which is illegal in redefinition |
| try { |
| instrumentation.redefineClasses(new ClassDefinition(DefineClass.class, buf)); |
| throw new RuntimeException("Class redefinition isn't allowed to change method names!"); |
| } |
| catch (UnsupportedOperationException uoe) { |
| // Expected because redefinition can't change the name of methods |
| } |
| } |
| // We expect just a single DefineClass instance because failed redefinitions should |
| // leave no garbage around. |
| printClassStats(1, false); |
| System.gc(); |
| System.out.println("System.gc()"); |
| // At least after a System.gc() we should definitely stay with a single instance! |
| printClassStats(1, true); |
| } |
| } |
| } |