1 /*
2 * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /**
25 * @test
26 * @requires vm.jvmci
27 * @library ../../../../../
28 * @modules jdk.internal.vm.ci/jdk.vm.ci.meta
29 * jdk.internal.vm.ci/jdk.vm.ci.runtime
30 * jdk.attach
31 * java.base/jdk.internal.misc
32 * @run junit/othervm -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:-UseJVMCICompiler -Djdk.attach.allowAttachSelf jdk.vm.ci.runtime.test.RedefineClassTest
33 */
34
35 package jdk.vm.ci.runtime.test;
36
37 import jdk.vm.ci.meta.ResolvedJavaMethod;
38 import org.junit.Assert;
39 import org.junit.Test;
40
41 import java.io.FileOutputStream;
42 import java.io.IOException;
43 import java.io.InputStream;
44 import java.lang.instrument.ClassFileTransformer;
45 import java.lang.instrument.IllegalClassFormatException;
46 import java.lang.instrument.Instrumentation;
47 import java.lang.management.ManagementFactory;
48 import java.lang.reflect.Method;
49 import java.nio.file.Files;
50 import java.nio.file.Path;
51 import java.security.ProtectionDomain;
52 import java.util.Arrays;
53 import java.util.jar.Attributes;
54 import java.util.jar.JarEntry;
55 import java.util.jar.JarOutputStream;
56 import java.util.jar.Manifest;
57
58 import static org.junit.Assume.assumeTrue;
59
60 /**
61 * Tests that {@link ResolvedJavaMethod}s are safe in the context of class redefinition being used
62 * to redefine the method to which they refer.
63 */
64 public class RedefineClassTest extends TypeUniverse {
65
66 static class Foo {
67 public static Object getName() {
68 return "foo";
69 }
70 }
71
72 @Test
73 public void test() throws Throwable {
74
75 Method fooMethod = Foo.class.getDeclaredMethod("getName");
76
77 ResolvedJavaMethod foo1 = metaAccess.lookupJavaMethod(fooMethod);
78 ResolvedJavaMethod foo2 = metaAccess.lookupJavaMethod(fooMethod);
79
80 String foo1Code = Arrays.toString(foo1.getCode());
81 String foo2Code = Arrays.toString(foo2.getCode());
82
83 Assert.assertEquals("foo", Foo.getName());
84
85 redefineFoo();
86 System.gc();
87
88 // Make sure the transformation happened
89 Assert.assertEquals("bar", Foo.getName());
90
91 Assert.assertEquals(foo1Code, Arrays.toString(foo1.getCode()));
92 Assert.assertEquals(foo2Code, Arrays.toString(foo1.getCode()));
93 }
94
95 /**
96 * Adds the class file bytes for a given class to a JAR stream.
97 */
98 static void add(JarOutputStream jar, Class<?> c) throws IOException {
99 String name = c.getName();
100 String classAsPath = name.replace('.', '/') + ".class";
101 jar.putNextEntry(new JarEntry(classAsPath));
102
103 InputStream stream = c.getClassLoader().getResourceAsStream(classAsPath);
104
105 int nRead;
106 byte[] buf = new byte[1024];
107 while ((nRead = stream.read(buf, 0, buf.length)) != -1) {
108 jar.write(buf, 0, nRead);
109 }
110
111 jar.closeEntry();
112 }
113
114 protected void redefineFoo() throws Exception {
115 Manifest manifest = new Manifest();
116 manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
117 Attributes mainAttrs = manifest.getMainAttributes();
118 mainAttrs.putValue("Agent-Class", FooAgent.class.getName());
119 mainAttrs.putValue("Can-Redefine-Classes", "true");
120 mainAttrs.putValue("Can-Retransform-Classes", "true");
121
122 Path jar = Files.createTempFile("myagent", ".jar");
123 try {
124 JarOutputStream jarStream = new JarOutputStream(new FileOutputStream(jar.toFile()), manifest);
125 add(jarStream, FooAgent.class);
126 add(jarStream, FooTransformer.class);
127 jarStream.close();
128
129 loadAgent(jar);
130 } finally {
131 Files.deleteIfExists(jar);
132 }
133 }
134
135 public static void loadAgent(Path agent) throws Exception {
136 String vmName = ManagementFactory.getRuntimeMXBean().getName();
137 int p = vmName.indexOf('@');
138 assumeTrue(p != -1);
139 String pid = vmName.substring(0, p);
140 ClassLoader cl = ClassLoader.getSystemClassLoader();
141 Class<?> c = Class.forName("com.sun.tools.attach.VirtualMachine", true, cl);
142 Method attach = c.getDeclaredMethod("attach", String.class);
143 Method loadAgent = c.getDeclaredMethod("loadAgent", String.class, String.class);
144 Method detach = c.getDeclaredMethod("detach");
145 Object vm = attach.invoke(null, pid);
146 loadAgent.invoke(vm, agent.toString(), "");
147 detach.invoke(vm);
148 }
149
150 public static class FooAgent {
151
152 public static void agentmain(@SuppressWarnings("unused") String args, Instrumentation inst) throws Exception {
153 if (inst.isRedefineClassesSupported() && inst.isRetransformClassesSupported()) {
154 inst.addTransformer(new FooTransformer(), true);
155 Class<?>[] allClasses = inst.getAllLoadedClasses();
156 for (int i = 0; i < allClasses.length; i++) {
157 Class<?> c = allClasses[i];
158 if (c == Foo.class) {
159 inst.retransformClasses(new Class<?>[]{c});
160 }
161 }
162 }
163 }
164 }
165
166 /**
167 * This transformer replaces the first instance of the constant "foo" in the class file for
168 * {@link Foo} with "bar".
169 */
170 static class FooTransformer implements ClassFileTransformer {
171
172 @Override
173 public byte[] transform(ClassLoader cl, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
174 if (Foo.class.equals(classBeingRedefined)) {
175 String cf = new String(classfileBuffer);
176 int i = cf.indexOf("foo");
177 Assert.assertTrue("cannot find \"foo\" constant in " + Foo.class.getSimpleName() + "'s class file", i > 0);
178 classfileBuffer[i] = 'b';
179 classfileBuffer[i + 1] = 'a';
180 classfileBuffer[i + 2] = 'r';
181 }
182 return classfileBuffer;
183 }
184 }
185 }