1 /*

     2  * Copyright (c) 2014, 2016, 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  * @bug 8076110

    27  * @summary Redefine running methods that have cached resolution errors

    28  * @library /test/lib

    29  * @modules java.base/jdk.internal.misc

    30  * @modules java.base/jdk.internal.org.objectweb.asm

    31  *          java.instrument

    32  *          jdk.jartool/sun.tools.jar

    33  * @run main RedefineClassHelper

    34  * @run main/othervm -javaagent:redefineagent.jar -Xlog:redefine+class+iklass+add=trace,redefine+class+iklass+purge=trace RedefineRunningMethodsWithResolutionErrors

    35  */

    36 

    37 import jdk.internal.org.objectweb.asm.ClassWriter;

    38 import jdk.internal.org.objectweb.asm.Label;

    39 import jdk.internal.org.objectweb.asm.MethodVisitor;

    40 import jdk.internal.org.objectweb.asm.Opcodes;

    41 

    42 import java.lang.reflect.InvocationTargetException;

    43 

    44 public class RedefineRunningMethodsWithResolutionErrors extends ClassLoader implements Opcodes {

    45 

    46     @Override

    47     protected Class<?> findClass(String name) throws ClassNotFoundException {

    48         if (name.equals("C")) {

    49             byte[] b = loadC(false);

    50             return defineClass(name, b, 0, b.length);

    51         } else {

    52             return super.findClass(name);

    53         }

    54     }

    55 

    56     private static byte[] loadC(boolean redefine) {

    57         ClassWriter cw = new ClassWriter(0);

    58 

    59         cw.visit(52, ACC_SUPER | ACC_PUBLIC, "C", null, "java/lang/Object", null);

    60         {

    61             MethodVisitor mv;

    62 

    63             mv = cw.visitMethod(ACC_PUBLIC | ACC_STATIC, "m", "()V", null, null);

    64             mv.visitCode();

    65 

    66             // First time we run we will:

    67             // 1) Cache resolution errors

    68             // 2) Redefine the class / method

    69             // 3) Try to read the resolution errors that were cached

    70             //

    71             // The redefined method will never run, throw error to be sure

    72             if (redefine) {

    73                 createThrowRuntimeExceptionCode(mv, "The redefined method was called");

    74             } else {

    75                 createMethodBody(mv);

    76             }

    77             mv.visitMaxs(3, 0);

    78             mv.visitEnd();

    79         }

    80         cw.visitEnd();

    81         return cw.toByteArray();

    82     }

    83 

    84     private static void createMethodBody(MethodVisitor mv) {

    85         Label classExists = new Label();

    86 

    87         // Cache resolution errors

    88         createLoadNonExistentClassCode(mv, classExists);

    89 

    90         // Redefine our own class and method

    91         mv.visitMethodInsn(INVOKESTATIC, "RedefineRunningMethodsWithResolutionErrors", "redefine", "()V");

    92 

    93         // Provoke the same error again to make sure the resolution error cache works

    94         createLoadNonExistentClassCode(mv, classExists);

    95 

    96         // Test passed

    97         mv.visitInsn(RETURN);

    98 

    99         mv.visitFrame(F_SAME, 0, new Object[0], 0, new Object[0]);

   100         mv.visitLabel(classExists);

   101 

   102         createThrowRuntimeExceptionCode(mv, "Loaded class that shouldn't exist (\"NonExistentClass\")");

   103     }

   104 

   105     private static void createLoadNonExistentClassCode(MethodVisitor mv, Label classExists) {

   106         Label tryLoadBegin = new Label();

   107         Label tryLoadEnd = new Label();

   108         Label catchLoadBlock = new Label();

   109         mv.visitTryCatchBlock(tryLoadBegin, tryLoadEnd, catchLoadBlock, "java/lang/NoClassDefFoundError");

   110 

   111         // Try to load a class that does not exist to provoke resolution errors

   112         mv.visitLabel(tryLoadBegin);

   113         mv.visitMethodInsn(INVOKESTATIC, "NonExistentClass", "nonExistentMethod", "()V");

   114         mv.visitLabel(tryLoadEnd);

   115 

   116         // No NoClassDefFoundError means NonExistentClass existed, which shouldn't happen

   117         mv.visitJumpInsn(GOTO, classExists);

   118 

   119         mv.visitFrame(F_SAME1, 0, new Object[0], 1, new Object[] { "java/lang/NoClassDefFoundError" });

   120         mv.visitLabel(catchLoadBlock);

   121 

   122         // Ignore the expected NoClassDefFoundError

   123         mv.visitInsn(POP);

   124     }

   125 

   126     private static void createThrowRuntimeExceptionCode(MethodVisitor mv, String msg) {

   127         mv.visitTypeInsn(NEW, "java/lang/RuntimeException");

   128         mv.visitInsn(DUP);

   129         mv.visitLdcInsn(msg);

   130         mv.visitMethodInsn(INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");

   131         mv.visitInsn(ATHROW);

   132     }

   133 

   134     private static Class<?> c;

   135 

   136     public static void redefine() throws Exception {

   137         RedefineClassHelper.redefineClass(c, loadC(true));

   138     }

   139 

   140     public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {

   141         c = Class.forName("C", true, new RedefineRunningMethodsWithResolutionErrors());

   142         c.getMethod("m").invoke(null);

   143     }

   144 }