1 /*
2 * Copyright (c) 2014, 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 /**
26 * @test
27 * @bug 8059556
28 * @compile -XDignore.symbol.file RedefineMethodUsedByMultipleMethodHandles.java
29 * @run main RedefineMethodUsedByMultipleMethodHandles
30 */
31
32 import java.io.*;
33 import java.lang.instrument.*;
34 import java.lang.invoke.*;
35 import java.lang.invoke.MethodHandles.Lookup;
36 import java.lang.management.*;
37 import java.lang.reflect.*;
38 import java.nio.file.*;
39 import java.security.*;
40 import java.util.jar.*;
41
42 import javax.tools.*;
43
44 import jdk.internal.org.objectweb.asm.*;
45
46 public class RedefineMethodUsedByMultipleMethodHandles {
47
48 static class Foo {
49 public static Object getName() {
50 return "foo";
51 }
52 }
53
54 public static void main(String[] args) throws Throwable {
55
56 Lookup lookup = MethodHandles.lookup();
57 Method fooMethod = Foo.class.getDeclaredMethod("getName");
58
59 // fooMH2 displaces fooMH1 from the MemberNamesTable
60 MethodHandle fooMH1 = lookup.unreflect(fooMethod);
61 MethodHandle fooMH2 = lookup.unreflect(fooMethod);
62
63 System.out.println("before invoke fooMH1 = " + fooMH1);
64 System.out.println("before invoke fooMH2 = " + fooMH2);
65
66 System.out.println("fooMH1.invoke = " + fooMH1.invokeExact());
67 System.out.println("fooMH2.invoke = " + fooMH2.invokeExact());
68
69 System.out.println("after invoke fooMH1 = " + fooMH1);
70 System.out.println("after invoke fooMH2 = " + fooMH2);
71
72 // Redefining Foo.getName() causes vmtarget to be updated
73 // in fooMH2 but not fooMH1
74 redefineFoo();
75
76 // Full GC causes fooMH1.vmtarget to be deallocated
77 System.gc();
78
79 System.out.println("after redef+gc fooMH1 = " + fooMH1);
80 System.out.println("after redef+gc fooMH2 = " + fooMH2);
81
82 System.out.println("fooMH1.invoke = " + fooMH1.invokeExact());
83 System.out.println("fooMH2.invoke = " + fooMH2.invokeExact());
84 }
85
86 /**
87 * Adds the class file bytes for {@code c} to {@code jar}.
88 */
89 static void add(JarOutputStream jar, Class<?> c) throws IOException {
90 String classAsPath = c.getName().replace('.', '/') + ".class";
91 jar.putNextEntry(new JarEntry(classAsPath));
92 InputStream stream = c.getClassLoader().getResourceAsStream(classAsPath);
93
94 int b;
95 while ((b = stream.read()) != -1) {
96 jar.write(b);
97 }
98 }
99
100 static void redefineFoo() throws Exception {
101 Manifest manifest = new Manifest();
102 manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
103 Attributes mainAttrs = manifest.getMainAttributes();
104 mainAttrs.putValue("Agent-Class", FooAgent.class.getName());
105 mainAttrs.putValue("Can-Redefine-Classes", "true");
106 mainAttrs.putValue("Can-Retransform-Classes", "true");
107
108 Path jar = Files.createTempFile("myagent", ".jar");
109 try {
110 JarOutputStream jarStream = new JarOutputStream(new FileOutputStream(jar.toFile()), manifest);
111 add(jarStream, FooAgent.class);
112 add(jarStream, FooTransformer.class);
113 jarStream.close();
114 runAgent(jar);
115 } finally {
116 Files.deleteIfExists(jar);
117 }
118 }
119
120 public static void runAgent(Path agent) throws Exception {
121 String vmName = ManagementFactory.getRuntimeMXBean().getName();
122 int p = vmName.indexOf('@');
123 assert p != -1 : "VM name not in <pid>@<host> format: " + vmName;
124 String pid = vmName.substring(0, p);
125 ClassLoader cl = ToolProvider.getSystemToolClassLoader();
126 Class<?> c = Class.forName("com.sun.tools.attach.VirtualMachine", true, cl);
127 Method attach = c.getDeclaredMethod("attach", String.class);
128 Method loadAgent = c.getDeclaredMethod("loadAgent", String.class);
129 Method detach = c.getDeclaredMethod("detach");
130 Object vm = attach.invoke(null, pid);
131 loadAgent.invoke(vm, agent.toString());
132 detach.invoke(vm);
133 }
134
135 public static class FooAgent {
136
137 public static void agentmain(@SuppressWarnings("unused") String args, Instrumentation inst) throws Exception {
138 assert inst.isRedefineClassesSupported();
139 assert inst.isRetransformClassesSupported();
140 inst.addTransformer(new FooTransformer(), true);
141 Class<?>[] classes = inst.getAllLoadedClasses();
142 for (int i = 0; i < classes.length; i++) {
143 Class<?> c = classes[i];
144 if (c == Foo.class) {
145 inst.retransformClasses(new Class[]{c});
146 }
147 }
148 }
149 }
150
151 // static class FooTransformer implements ClassFileTransformer, Opcodes {
152 static class FooTransformer implements ClassFileTransformer {
153
154 @Override
155 public byte[] transform(ClassLoader cl, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
156 if (Foo.class.equals(classBeingRedefined)) {
157 System.out.println("redefining " + classBeingRedefined);
158 ClassReader cr = new ClassReader(classfileBuffer);
159 ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_FRAMES);
160 ClassVisitor adapter = new ClassVisitor(Opcodes.ASM5, cw) {
161 @Override
162 public MethodVisitor visitMethod(int access, String base, String desc, String signature, String[] exceptions) {
163 MethodVisitor mv = cv.visitMethod(access, base, desc, signature, exceptions);
164 if (mv != null) {
165 mv = new MethodVisitor(Opcodes.ASM5, mv) {
166 @Override
167 public void visitLdcInsn(Object cst) {
168 System.out.println("replacing \"" + cst + "\" with \"bar\"");
169 mv.visitLdcInsn("bar");
170 }
171 };
172 }
173 return mv;
174 }
175 };
176
177 cr.accept(adapter, ClassReader.SKIP_FRAMES);
178 cw.visitEnd();
179 return cw.toByteArray();
180 }
181 return classfileBuffer;
182 }
183 }
184 }