1 /*
   2  * Copyright (c) 2014, 2018, 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 package vm.mlvm.anonloader.share;
  25 
  26 import jdk.internal.org.objectweb.asm.ClassReader;
  27 import vm.mlvm.share.MlvmTest;
  28 import vm.mlvm.share.MlvmTestExecutor;
  29 import vm.mlvm.share.Env;
  30 import vm.share.FileUtils;
  31 import vm.share.UnsafeAccess;
  32 import vm.share.options.Option;
  33 
  34 /**
  35  * This is a base class for kind of tests, which modify the parent class name of test dummy class vm.mlvm.share.AnonkTestee01
  36  * with an arbitrary string, load the modified class using Unsafe.defineAnonymousClass and instantiate it.
  37  * <p>
  38  * The tests can extend this class or use it from command-line to provide the actual data:
  39  * <ul>
  40  *   <li>new parent class name,
  41  *   <li>optionally the list of expected exceptions to be thrown during class loading and instantiation
  42  *       (see {@link vm.mlvm.share.MlvmTest#setRequiredExceptions(Class<? extends Throwable>... classes)} for details)
  43  * </ul>
  44  */
  45 
  46 public class ReplaceClassParentTest extends MlvmTest {
  47 
  48     @Option(name = "newParent", default_value = "", description = "String to replace the name of the parent class of the testee")
  49     private String newParentOpt;
  50 
  51     public void setReplaceParent(String newParent) {
  52         newParentOpt = newParent;
  53     }
  54 
  55     private static final Class<?> TESTEE_CLASS = AnonkTestee01.class;
  56 
  57     public ReplaceClassParentTest() {
  58     }
  59 
  60     public boolean run() throws Throwable {
  61         byte[] classBytes = FileUtils.readClass(TESTEE_CLASS.getName());
  62         ClassReader reader = new ClassReader(classBytes);
  63         int superclassNameIdx = reader.readUnsignedShort(reader.header + 4);
  64         int cpLength = reader.getItemCount();
  65         if (superclassNameIdx == 0) {
  66             throw new RuntimeException("Test bug: unable to find super class"
  67                     + " name index");
  68         }
  69         Env.traceDebug("Superclass name CP index: " + superclassNameIdx
  70                 + "; replacing CP entry with '" + newParentOpt + "'");
  71         // now, construction of cp patch
  72         Object cpPatch[] = new Object[cpLength];
  73         cpPatch[superclassNameIdx] = newParentOpt;
  74         // define and instantiate
  75         UnsafeAccess.unsafe.defineAnonymousClass(TESTEE_CLASS, classBytes,
  76                 cpPatch).newInstance();
  77         // Whether test should pass or fail should be specified via requireExceptions mechanism in MlvmTest
  78         return true;
  79 
  80     }
  81 
  82     public static void main(String[] args) {
  83         MlvmTestExecutor.launch(args);
  84     }
  85 }