1 /*
2 * Copyright (c) 2019, 2024, 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
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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.
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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 * @summary Tests that java.lang.Object cannot be redefined/retransformed
27 * @requires vm.jvmti
28 * @library /test/lib
29 * @modules java.instrument
30 * jdk.jartool/sun.tools.jar
31 * @run main RedefineObject buildagent
32 * @run main/othervm -javaagent:redefineagent.jar RedefineObject
33 */
34
35 import jdk.test.lib.helpers.ClassFileInstaller;
36 import java.io.FileNotFoundException;
37 import java.io.PrintWriter;
38 import java.lang.instrument.ClassFileTransformer;
39 import java.lang.instrument.Instrumentation;
40 import java.lang.instrument.UnmodifiableClassException;
41 import java.security.ProtectionDomain;
42
43 public class RedefineObject {
44
45 static Instrumentation inst;
46
47 public static void premain(String agentArgs, Instrumentation inst) {
48 RedefineObject.inst = inst;
49 }
50
51 static class Transformer implements ClassFileTransformer {
52 // set to true if transform method called to transform java.lang.Object
53 private boolean transformObjectInvoked;
54
55 @Override
56 public byte[] transform(ClassLoader loader,
57 String className,
58 Class<?> classBeingRedefined,
59 ProtectionDomain protectionDomain,
60 byte[] classfileBuffer) {
61 if (className.contains("java/lang/Object")) {
62 transformObjectInvoked = true;
63 }
64 return null;
65 }
66
67 boolean transformObjectInvoked() {
68 return transformObjectInvoked;
69 }
70 }
71
72 private static void buildAgent() {
73 try {
74 ClassFileInstaller.main("RedefineObject");
75 } catch (Exception e) {
76 throw new RuntimeException("Could not write agent classfile", e);
77 }
78
79 try (PrintWriter pw = new PrintWriter("MANIFEST.MF")) {
80 pw.println("Premain-Class: RedefineObject");
81 pw.println("Agent-Class: RedefineObject");
82 pw.println("Can-Retransform-Classes: true");
83 } catch (FileNotFoundException e) {
84 throw new RuntimeException("Could not write manifest file for the agent", e);
85 }
86
87 sun.tools.jar.Main jarTool = new sun.tools.jar.Main(System.out, System.err, "jar");
88 if (!jarTool.run(new String[] { "-cmf", "MANIFEST.MF", "redefineagent.jar", "RedefineObject.class" })) {
89 throw new RuntimeException("Could not write the agent jar file");
90 }
91 }
92
93 public static void main(String[] args) throws Exception {
94 if (args.length == 1 && args[0].equals("buildagent")) {
95 buildAgent();
96 return;
97 }
98
99 if (inst == null) {
100 throw new RuntimeException("Instrumentation object was null");
101 }
102
103 if (inst.isModifiableClass(Object.class)) {
104 throw new RuntimeException("java.lang.Object should not be modifable");
105 }
106
107 var transformer = new Transformer();
108 inst.addTransformer(transformer, true);
109 try {
110 inst.retransformClasses(Object.class);
111 throw new RuntimeException("UnmodifiableClassException not thrown by retransformClasses");
112 } catch (UnmodifiableClassException e) {
113 // expected
114 }
115 if (transformer.transformObjectInvoked()) {
116 throw new RuntimeException();
117 }
118 }
119 }