1 /*
2  * Copyright (C) 2017 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 import java.lang.reflect.*;
18 
19 public class Main {
20   public static final String TEST_NAME = "998-redefine-use-after-free";
21   public static final int REPS = 1000;
22   public static final int STEP = 100;
23 
main(String[] args)24   public static void main(String[] args) throws Exception {
25     for (int i = 0; i < REPS; i += STEP) {
26       runSeveralTimes(STEP);
27     }
28   }
29 
getClassLoaderFor(String location)30   public static ClassLoader getClassLoaderFor(String location) throws Exception {
31     try {
32       Class<?> class_loader_class = Class.forName("dalvik.system.PathClassLoader");
33       Constructor<?> ctor = class_loader_class.getConstructor(String.class, ClassLoader.class);
34       return (ClassLoader)ctor.newInstance(location + "/" + TEST_NAME + "-ex.jar",
35                                            Main.class.getClassLoader());
36     } catch (ClassNotFoundException e) {
37       // Running on RI. Use URLClassLoader.
38       return new java.net.URLClassLoader(
39           new java.net.URL[] { new java.net.URL("file://" + location + "/classes-ex/") });
40     }
41   }
42 
43   // Run the redefinition several times on a single class-loader to try to trigger the
44   // Use-after-free bug b/62237378
runSeveralTimes(int times)45   public static void runSeveralTimes(int times) throws Exception {
46     ClassLoader c = getClassLoaderFor(System.getenv("DEX_LOCATION"));
47 
48     Class<?> klass = (Class<?>)c.loadClass("DexCacheSmash");
49     Method m = klass.getDeclaredMethod("run");
50     for (int i = 0 ; i < times; i++) {
51       m.invoke(null);
52     }
53   }
54 }
55