blob: 832b1f08ee5fcf3c9198619b8c15a30a3fdc5827 [file] [log] [blame]
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.List;
class MyClassLoader extends ClassLoader {
MyClassLoader() throws Exception {
super(MyClassLoader.class.getClassLoader());
// Some magic to get access to the pathList field of BaseDexClassLoader.
ClassLoader loader = getClass().getClassLoader();
Class<?> baseDexClassLoader = loader.getClass().getSuperclass();
Field f = baseDexClassLoader.getDeclaredField("pathList");
f.setAccessible(true);
Object pathList = f.get(loader);
// Some magic to get access to the dexField field of pathList.
f = pathList.getClass().getDeclaredField("dexElements");
f.setAccessible(true);
dexElements = (Object[]) f.get(pathList);
dexFileField = dexElements[0].getClass().getDeclaredField("dexFile");
dexFileField.setAccessible(true);
}
Object[] dexElements;
Field dexFileField;
static ClassLoader level1ClassLoader;
protected Class<?> loadClass(String className, boolean resolve) throws ClassNotFoundException {
if (this != level1ClassLoader) {
if (className.equals("Level1")) {
return level1ClassLoader.loadClass(className);
} else if (className.equals("Level2")) {
throw new ClassNotFoundException("None of my methods require Level2!");
} else if (!className.equals("LoadedByMyClassLoader")) {
// We're only going to handle LoadedByMyClassLoader.
return getParent().loadClass(className);
}
} else {
if (className != "Level1" && className != "Level2") {
return getParent().loadClass(className);
}
}
// Mimic what DexPathList.findClass is doing.
try {
for (Object element : dexElements) {
Object dex = dexFileField.get(element);
Method method = dex.getClass().getDeclaredMethod(
"loadClassBinaryName", String.class, ClassLoader.class, List.class);
if (dex != null) {
Class clazz = (Class)method.invoke(dex, className, this, null);
if (clazz != null) {
return clazz;
}
}
}
} catch (Exception e) { /* Ignore */ }
return null;
}
}
class LoadedByMyClassLoader {
public static void bar() {
Level1.$inline$bar();
}
}
class Main {
public static void main(String[] args) throws Exception {
System.loadLibrary(args[0]);
// Clone resolved methods, to restore the original version just
// before we walk the stack in $noinline$bar.
savedResolvedMethods = cloneResolvedMethods(Main.class);
MyClassLoader o = new MyClassLoader();
MyClassLoader.level1ClassLoader = new MyClassLoader();
Class foo = o.loadClass("LoadedByMyClassLoader");
Method m = foo.getDeclaredMethod("bar");
try {
m.invoke(null);
} catch (Error e) { /* Ignore */ }
}
public static void $inline$bar() {
}
public static void $noinline$bar() {
try {
// Be evil and clear all dex cache entries.
Field f = Class.class.getDeclaredField("dexCache");
f.setAccessible(true);
Object dexCache = f.get(Main.class);
f = dexCache.getClass().getDeclaredField("resolvedTypes");
f.setAccessible(true);
Object[] array = (Object[]) f.get(dexCache);
for (int i = 0; i < array.length; i++) {
array[i] = null;
}
restoreResolvedMethods(Main.class, savedResolvedMethods);
} catch (Throwable t) { /* Ignore */ }
// This will walk the stack, trying to resolve methods in it.
// Because we cleared dex cache entries, we will have to find
// classes again, which require to use the correct class loader
// in the presence of inlining.
new Exception().printStackTrace();
}
static Object savedResolvedMethods;
static native Object cloneResolvedMethods(Class<?> cls);
static native void restoreResolvedMethods(Class<?> cls, Object saved);
}