1 /*
2  * Copyright (C) 2019 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 art.Redefinition;
18 import java.lang.invoke.*;
19 import java.lang.reflect.Field;
20 import java.util.Base64;
21 import java.util.concurrent.CountDownLatch;
22 
23 public class Main {
24   public static final class Transform {
25     static {
26     }
27 
28     public static Object foo = null;
29   }
30 
31   /**
32    * Base64 encoded dex bytes for:
33    *
34    * public static final class Transform {
35    *   static {}
36    *   public static Object bar = null;
37    *   public static Object foo = null;
38    * }
39    */
40   public static final byte[] DEX_BYTES =
41       Base64.getDecoder()
42           .decode(
43               "ZGV4CjAzNQCjkRjcSr1RJO8FnnCjHV/8h6keJP/+P3WQAwAAcAAAAHhWNBIAAAAAAAAAANgCAAAQ"
44                   + "AAAAcAAAAAYAAACwAAAAAQAAAMgAAAACAAAA1AAAAAMAAADkAAAAAQAAAPwAAAB0AgAAHAEAAFwB"
45                   + "AABmAQAAbgEAAIABAACIAQAArAEAAMwBAADgAQAA6wEAAPYBAAD5AQAABgIAAAsCAAAQAgAAFgIA"
46                   + "AB0CAAACAAAAAwAAAAQAAAAFAAAABgAAAAkAAAAJAAAABQAAAAAAAAAAAAQACwAAAAAABAAMAAAA"
47                   + "AAAAAAAAAAAAAAAAAQAAAAQAAAABAAAAAAAAABEAAAAEAAAAAAAAAAcAAADIAgAApAIAAAAAAAAB"
48                   + "AAAAAAAAAFABAAAGAAAAEgBpAAAAaQABAA4AAQABAAEAAABVAQAABAAAAHAQAgAAAA4ABwAOPAAF"
49                   + "AA4AAAAACDxjbGluaXQ+AAY8aW5pdD4AEExNYWluJFRyYW5zZm9ybTsABkxNYWluOwAiTGRhbHZp"
50                   + "ay9hbm5vdGF0aW9uL0VuY2xvc2luZ0NsYXNzOwAeTGRhbHZpay9hbm5vdGF0aW9uL0lubmVyQ2xh"
51                   + "c3M7ABJMamF2YS9sYW5nL09iamVjdDsACU1haW4uamF2YQAJVHJhbnNmb3JtAAFWAAthY2Nlc3NG"
52                   + "bGFncwADYmFyAANmb28ABG5hbWUABXZhbHVlAHZ+fkQ4eyJjb21waWxhdGlvbi1tb2RlIjoiZGVi"
53                   + "dWciLCJtaW4tYXBpIjoxLCJzaGEtMSI6IjI4YmNlZjUwYWM4NTk3Y2YyMmU4OTJiMWJjM2EzYjky"
54                   + "Yjc0ZTcwZTkiLCJ2ZXJzaW9uIjoiMS42LjMyLWRldiJ9AAICAQ4YAQIDAgoEGQ0XCAIAAgAACQEJ"
55                   + "AIiABJwCAYGABLgCAAAAAAIAAACVAgAAmwIAALwCAAAAAAAAAAAAAAAAAAAPAAAAAAAAAAEAAAAA"
56                   + "AAAAAQAAABAAAABwAAAAAgAAAAYAAACwAAAAAwAAAAEAAADIAAAABAAAAAIAAADUAAAABQAAAAMA"
57                   + "AADkAAAABgAAAAEAAAD8AAAAASAAAAIAAAAcAQAAAyAAAAIAAABQAQAAAiAAABAAAABcAQAABCAA"
58                   + "AAIAAACVAgAAACAAAAEAAACkAgAAAxAAAAIAAAC4AgAABiAAAAEAAADIAgAAABAAAAEAAADYAgAA");
59 
assertEquals(Object a, Object b)60   public static void assertEquals(Object a, Object b) {
61     if (a != b) {
62       throw new Error("Expected " + b + ", got " + a);
63     }
64   }
65 
assertAllEquals(Object[] a, Object b)66   public static void assertAllEquals(Object[] a, Object b) {
67     boolean failed = false;
68     String msg = "";
69     for (int i = 0; i < a.length; i++) {
70       if (a[i] != b) {
71         failed = true;
72         msg += "Expected " + b + ", got a[" + i + "] (" + a[i] + "), ";
73       }
74     }
75     if (failed) {
76       throw new Error(msg);
77     }
78   }
79 
main(String[] args)80   public static void main(String[] args) throws Exception, Throwable {
81     System.loadLibrary(args[0]);
82     Field f = Transform.class.getDeclaredField("foo");
83     Transform.foo = "THIS IS A FOO VALUE";
84     assertEquals(f.get(null), Transform.foo);
85     final int num_threads = 10;
86     Object[] results = new Object[num_threads];
87     Thread[] threads = new Thread[num_threads];
88     CountDownLatch start_latch = new CountDownLatch(num_threads);
89     CountDownLatch continue_latch = new CountDownLatch(1);
90     for (int i = 0; i < num_threads; i++) {
91       final int id = i;
92       threads[id] =
93           new Thread(
94               () -> {
95                 try {
96                   MethodHandle mh =
97                       NativeFieldScopeCheck(
98                           f,
99                           () -> {
100                             try {
101                               start_latch.countDown();
102                               continue_latch.await();
103                             } catch (Exception e) {
104                               throw new Error("failed!", e);
105                             }
106                           });
107                   results[id] = mh.invokeExact();
108                 } catch (Throwable t) {
109                   throw new Error("Failed", t);
110                 }
111               },
112               "Target thread " + id);
113       threads[id].start();
114     }
115     start_latch.await();
116     Redefinition.doCommonStructuralClassRedefinition(Transform.class, DEX_BYTES);
117     continue_latch.countDown();
118     for (Thread t : threads) {
119       t.join();
120     }
121     assertAllEquals(results, Transform.foo);
122   }
123 
124   // Hold the field as a ArtField, run the 'test' function, turn the ArtField into a MethodHandle
125   // directly and return that.
NativeFieldScopeCheck(Field in, Runnable test)126   public static native MethodHandle NativeFieldScopeCheck(Field in, Runnable test);
127 }
128