1 /*
2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2017 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /**
26 * @test
27 * @bug 8173743
28 * @requires vm.compMode != "Xcomp"
29 * @summary Failures during class definition can lead to memory leaks in metaspace
30 * @requires vm.opt.final.ClassUnloading
31 * @library /test/lib
32 * @run main/othervm test.DefineClass defineClass
33 * @run main/othervm test.DefineClass defineSystemClass
34 * @run main/othervm -XX:+AllowParallelDefineClass
35 test.DefineClass defineClassParallel
36 * @run main/othervm -XX:-AllowParallelDefineClass
37 test.DefineClass defineClassParallel
38 * @run main/othervm -Djdk.attach.allowAttachSelf test.DefineClass redefineClass
39 * @run main/othervm -Djdk.attach.allowAttachSelf test.DefineClass redefineClassWithError
40 * @author volker.simonis@gmail.com
41 */
42
43 package test;
44
45 import java.io.ByteArrayOutputStream;
46 import java.io.File;
47 import java.io.FileOutputStream;
48 import java.io.InputStream;
49 import java.lang.instrument.ClassDefinition;
50 import java.lang.instrument.Instrumentation;
51 import java.lang.management.ManagementFactory;
52 import java.util.Scanner;
53 import java.util.concurrent.CountDownLatch;
54 import java.util.jar.Attributes;
55 import java.util.jar.JarEntry;
56 import java.util.jar.JarOutputStream;
57 import java.util.jar.Manifest;
58
59 import javax.management.MBeanServer;
60 import javax.management.ObjectName;
61
62 import com.sun.tools.attach.VirtualMachine;
63
64 import jdk.test.lib.process.ProcessTools;
65
66 public class DefineClass {
67
68 private static Instrumentation instrumentation;
69
70 public void getID(CountDownLatch start, CountDownLatch stop) {
71 String id = "AAAAAAAA";
72 System.out.println(id);
73 try {
74 // Signal that we've entered the activation..
75 start.countDown();
76 //..and wait until we can leave it.
77 stop.await();
78 } catch (InterruptedException e) {
79 e.printStackTrace();
80 }
81 System.out.println(id);
82 return;
83 }
84
85 private static class MyThread extends Thread {
86 private DefineClass dc;
87 private CountDownLatch start, stop;
88
89 public MyThread(DefineClass dc, CountDownLatch start, CountDownLatch stop) {
90 this.dc = dc;
91 this.start = start;
92 this.stop = stop;
93 }
94
95 public void run() {
96 dc.getID(start, stop);
97 }
98 }
99
100 private static class ParallelLoadingThread extends Thread {
101 private MyParallelClassLoader pcl;
102 private CountDownLatch stop;
103 private byte[] buf;
104
105 public ParallelLoadingThread(MyParallelClassLoader pcl, byte[] buf, CountDownLatch stop) {
106 this.pcl = pcl;
107 this.stop = stop;
108 this.buf = buf;
109 }
110
111 public void run() {
112 try {
113 stop.await();
114 } catch (InterruptedException e) {
115 e.printStackTrace();
116 }
117 try {
118 @SuppressWarnings("unchecked")
119 Class<DefineClass> dc = (Class<DefineClass>) pcl.myDefineClass(DefineClass.class.getName(), buf, 0, buf.length);
120 }
121 catch (LinkageError jle) {
122 // Expected with a parallel capable class loader and
123 // -XX:+AllowParallelDefineClass
124 pcl.incrementLinkageErrors();
125 }
126
127 }
128 }
129
130 static private class MyClassLoader extends ClassLoader {
131 public Class<?> myDefineClass(String name, byte[] b, int off, int len) throws ClassFormatError {
132 return defineClass(name, b, off, len, null);
133 }
134 }
135
136 static private class MyParallelClassLoader extends ClassLoader {
137 static {
138 System.out.println("parallelCapable : " + registerAsParallelCapable());
139 }
140 public Class<?> myDefineClass(String name, byte[] b, int off, int len) throws ClassFormatError {
141 return defineClass(name, b, off, len, null);
142 }
143 public synchronized void incrementLinkageErrors() {
144 linkageErrors++;
145 }
146 public int getLinkageErrors() {
147 return linkageErrors;
148 }
149 private volatile int linkageErrors;
150 }
151
152 public static void agentmain(String args, Instrumentation inst) {
153 System.out.println("Loading Java Agent.");
154 instrumentation = inst;
155 }
156
157
158 private static void loadInstrumentationAgent(String myName, byte[] buf) throws Exception {
159 // Create agent jar file on the fly
160 Manifest m = new Manifest();
161 m.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
162 m.getMainAttributes().put(new Attributes.Name("Agent-Class"), myName);
163 m.getMainAttributes().put(new Attributes.Name("Can-Redefine-Classes"), "true");
164 File jarFile = File.createTempFile("agent", ".jar");
165 jarFile.deleteOnExit();
166 JarOutputStream jar = new JarOutputStream(new FileOutputStream(jarFile), m);
167 jar.putNextEntry(new JarEntry(myName.replace('.', '/') + ".class"));
168 jar.write(buf);
169 jar.close();
170 String pid = Long.toString(ProcessTools.getProcessId());
171 System.out.println("Our pid is = " + pid);
172 VirtualMachine vm = VirtualMachine.attach(pid);
173 vm.loadAgent(jarFile.getAbsolutePath());
174 }
175
176 private static byte[] getBytecodes(String myName) throws Exception {
177 InputStream is = DefineClass.class.getResourceAsStream(myName + ".class");
178 ByteArrayOutputStream baos = new ByteArrayOutputStream();
179 byte[] buf = new byte[4096];
180 int len;
181 while ((len = is.read(buf)) != -1) baos.write(buf, 0, len);
182 buf = baos.toByteArray();
183 System.out.println("sizeof(" + myName + ".class) == " + buf.length);
184 return buf;
185 }
186
187 private static int getStringIndex(String needle, byte[] buf) {
188 return getStringIndex(needle, buf, 0);
189 }
190
191 private static int getStringIndex(String needle, byte[] buf, int offset) {
192 outer:
193 for (int i = offset; i < buf.length - offset - needle.length(); i++) {
194 for (int j = 0; j < needle.length(); j++) {
195 if (buf[i + j] != (byte)needle.charAt(j)) continue outer;
196 }
197 return i;
198 }
199 return 0;
200 }
201
202 private static void replaceString(byte[] buf, String name, int index) {
203 for (int i = index; i < index + name.length(); i++) {
204 buf[i] = (byte)name.charAt(i - index);
205 }
206 }
207
208 private static MBeanServer mbserver = ManagementFactory.getPlatformMBeanServer();
209
210 private static int getClassStats(String pattern) {
211 try {
212 ObjectName diagCmd = new ObjectName("com.sun.management:type=DiagnosticCommand");
213
214 String result = (String)mbserver.invoke(diagCmd , "gcClassHistogram" , new Object[] { null }, new String[] {String[].class.getName()});
215 int count = 0;
216 try (Scanner s = new Scanner(result)) {
217 if (s.hasNextLine()) {
218 System.out.println(s.nextLine());
219 }
220 while (s.hasNextLine()) {
221 String l = s.nextLine();
222 if (l.endsWith(pattern)) {
223 count++;
224 System.out.println(l);
225 }
226 }
227 }
228 return count;
229 }
230 catch (Exception e) {
231 throw new RuntimeException("Test failed because we can't read the class statistics!", e);
232 }
233 }
234
235 private static void printClassStats(int expectedCount, boolean reportError) {
236 int count = getClassStats("DefineClass");
237 String res = "Should have " + expectedCount +
238 " DefineClass instances and we have: " + count;
239 System.out.println(res);
240 if (reportError && count != expectedCount) {
241 throw new RuntimeException(res);
242 }
243 }
244
245 public static final int ITERATIONS = 10;
246
247 public static void main(String[] args) throws Exception {
248 String myName = DefineClass.class.getName();
249 byte[] buf = getBytecodes(myName.substring(myName.lastIndexOf(".") + 1));
250 int iterations = (args.length > 1 ? Integer.parseInt(args[1]) : ITERATIONS);
251
252 if (args.length == 0 || "defineClass".equals(args[0])) {
253 MyClassLoader cl = new MyClassLoader();
254 for (int i = 0; i < iterations; i++) {
255 try {
256 @SuppressWarnings("unchecked")
257 Class<DefineClass> dc = (Class<DefineClass>) cl.myDefineClass(myName, buf, 0, buf.length);
258 System.out.println(dc);
259 }
260 catch (LinkageError jle) {
261 // Can only define once!
262 if (i == 0) throw new Exception("Should succeed the first time.");
263 }
264 }
265 // We expect to have two instances of DefineClass here: the initial version in which we are
266 // executing and another version which was loaded into our own classloader 'MyClassLoader'.
267 // All the subsequent attempts to reload DefineClass into our 'MyClassLoader' should have failed.
268 // The ClassLoaderDataGraph has the failed instances recorded at least until the next GC.
269 printClassStats(2, false);
270 System.gc();
271 System.out.println("System.gc()");
272 // At least after System.gc() the failed loading attempts should leave no instances around!
273 printClassStats(2, true);
274 }
275 else if ("defineSystemClass".equals(args[0])) {
276 MyClassLoader cl = new MyClassLoader();
277 int index = getStringIndex("test/DefineClass", buf);
278 replaceString(buf, "java/DefineClass", index);
279 while ((index = getStringIndex("Ltest/DefineClass;", buf, index + 1)) != 0) {
280 replaceString(buf, "Ljava/DefineClass;", index);
281 }
282 index = getStringIndex("test.DefineClass", buf);
283 replaceString(buf, "java.DefineClass", index);
284
285 for (int i = 0; i < iterations; i++) {
286 try {
287 @SuppressWarnings("unchecked")
288 Class<DefineClass> dc = (Class<DefineClass>) cl.myDefineClass(null, buf, 0, buf.length);
289 throw new RuntimeException("Defining a class in the 'java' package should fail!");
290 }
291 catch (java.lang.SecurityException jlse) {
292 // Expected, because we're not allowed to define a class in the 'java' package
293 }
294 }
295 // We expect to stay with one (the initial) instances of DefineClass.
296 // All the subsequent attempts to reload DefineClass into the 'java' package should have failed.
297 // The ClassLoaderDataGraph has the failed instances recorded at least until the next GC.
298 printClassStats(1, false);
299 System.gc();
300 System.out.println("System.gc()");
301 // At least after System.gc() the failed loading attempts should leave no instances around!
302 printClassStats(1, true);
303 }
304 else if ("defineClassParallel".equals(args[0])) {
305 MyParallelClassLoader pcl = new MyParallelClassLoader();
306 CountDownLatch stop = new CountDownLatch(1);
307
308 Thread[] threads = new Thread[iterations];
309 for (int i = 0; i < iterations; i++) {
310 (threads[i] = new ParallelLoadingThread(pcl, buf, stop)).start();
311 }
312 stop.countDown(); // start parallel class loading..
313 // ..and wait until all threads loaded the class
314 for (int i = 0; i < iterations; i++) {
315 threads[i].join();
316 }
317 System.out.print("Counted " + pcl.getLinkageErrors() + " LinkageErrors ");
318 System.out.println(pcl.getLinkageErrors() == 0 ?
319 "" : "(use -XX:+AllowParallelDefineClass to avoid this)");
320 System.gc();
321 System.out.println("System.gc()");
322 // After System.gc() we expect to remain with two instances: one is the initial version which is
323 // kept alive by this main method and another one in the parallel class loader.
324 printClassStats(2, true);
325 }
326 else if ("redefineClass".equals(args[0])) {
327 loadInstrumentationAgent(myName, buf);
328 int index = getStringIndex("AAAAAAAA", buf);
329 CountDownLatch stop = new CountDownLatch(1);
330
331 Thread[] threads = new Thread[iterations];
332 for (int i = 0; i < iterations; i++) {
333 buf[index] = (byte) ('A' + i + 1); // Change string constant in getID() which is legal in redefinition
334 instrumentation.redefineClasses(new ClassDefinition(DefineClass.class, buf));
335 DefineClass dc = DefineClass.class.newInstance();
336 CountDownLatch start = new CountDownLatch(1);
337 (threads[i] = new MyThread(dc, start, stop)).start();
338 start.await(); // Wait until the new thread entered the getID() method
339 }
340 // We expect to have one instance for each redefinition because they are all kept alive by an activation
341 // plus the initial version which is kept active by this main method.
342 printClassStats(iterations + 1, true);
343 stop.countDown(); // Let all threads leave the DefineClass.getID() activation..
344 // ..and wait until really all of them returned from DefineClass.getID()
345 for (int i = 0; i < iterations; i++) {
346 threads[i].join();
347 }
348 System.gc();
349 System.out.println("System.gc()");
350 // After System.gc() we expect to remain with two instances: one is the initial version which is
351 // kept alive by this main method and another one which is the latest redefined version.
352 printClassStats(2, true);
353 }
354 else if ("redefineClassWithError".equals(args[0])) {
355 loadInstrumentationAgent(myName, buf);
356 int index = getStringIndex("getID", buf);
357
358 for (int i = 0; i < iterations; i++) {
359 buf[index] = (byte) 'X'; // Change getID() to XetID() which is illegal in redefinition
360 try {
361 instrumentation.redefineClasses(new ClassDefinition(DefineClass.class, buf));
362 throw new RuntimeException("Class redefinition isn't allowed to change method names!");
363 }
364 catch (UnsupportedOperationException uoe) {
365 // Expected because redefinition can't change the name of methods
366 }
367 }
368 // We expect just a single DefineClass instance because failed redefinitions should
369 // leave no garbage around.
370 // The ClassLoaderDataGraph has the failed instances recorded at least until the next GC.
371 printClassStats(1, false);
372 System.gc();
373 System.out.println("System.gc()");
374 // At least after a System.gc() we should definitely stay with a single instance!
375 printClassStats(1, true);
376 }
377 }
378 }