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| 1 | +/* |
| 2 | + * Copyright (C) 2020 The Guava Authors |
| 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 | +package com.google.common.util.concurrent; |
| 18 | + |
| 19 | +import java.net.URLClassLoader; |
| 20 | +import java.security.Permission; |
| 21 | +import java.util.HashMap; |
| 22 | +import java.util.Map; |
| 23 | +import java.util.PropertyPermission; |
| 24 | +import java.util.concurrent.CountDownLatch; |
| 25 | +import java.util.concurrent.ForkJoinPool; |
| 26 | +import java.util.concurrent.TimeUnit; |
| 27 | +import javax.annotation.concurrent.GuardedBy; |
| 28 | +import junit.framework.TestCase; |
| 29 | + |
| 30 | +/** Tests for {@link AbstractFuture} using an innocuous thread. */ |
| 31 | + |
| 32 | +public class AbstractFutureInnocuousThreadTest extends TestCase { |
| 33 | + private ClassLoader oldClassLoader; |
| 34 | + private URLClassLoader classReloader; |
| 35 | + private Class<?> settableFutureClass; |
| 36 | + private SecurityManager oldSecurityManager; |
| 37 | + |
| 38 | + @Override |
| 39 | + protected void setUp() throws Exception { |
| 40 | + // Load the "normal" copy of SettableFuture and related classes. |
| 41 | + SettableFuture<?> unused = SettableFuture.create(); |
| 42 | + // Hack to load AbstractFuture et. al. in a new classloader so that it tries to re-read the |
| 43 | + // cancellation-cause system property. This allows us to test what happens if reading the |
| 44 | + // property is forbidden and then continue running tests normally in one jvm without resorting |
| 45 | + // to even crazier hacks to reset static final boolean fields. |
| 46 | + final String concurrentPackage = SettableFuture.class.getPackage().getName(); |
| 47 | + classReloader = |
| 48 | + new URLClassLoader(ClassPathUtil.getClassPathUrls()) { |
| 49 | + @GuardedBy("loadedClasses") |
| 50 | + final Map<String, Class<?>> loadedClasses = new HashMap<>(); |
| 51 | + |
| 52 | + @Override |
| 53 | + public Class<?> loadClass(String name) throws ClassNotFoundException { |
| 54 | + if (name.startsWith(concurrentPackage) |
| 55 | + // Use other classloader for ListenableFuture, so that the objects can interact |
| 56 | + && !ListenableFuture.class.getName().equals(name)) { |
| 57 | + synchronized (loadedClasses) { |
| 58 | + Class<?> toReturn = loadedClasses.get(name); |
| 59 | + if (toReturn == null) { |
| 60 | + toReturn = super.findClass(name); |
| 61 | + loadedClasses.put(name, toReturn); |
| 62 | + } |
| 63 | + return toReturn; |
| 64 | + } |
| 65 | + } |
| 66 | + return super.loadClass(name); |
| 67 | + } |
| 68 | + }; |
| 69 | + oldClassLoader = Thread.currentThread().getContextClassLoader(); |
| 70 | + Thread.currentThread().setContextClassLoader(classReloader); |
| 71 | + |
| 72 | + oldSecurityManager = System.getSecurityManager(); |
| 73 | + /* |
| 74 | + * TODO(cpovirk): Why couldn't I get this to work with PermissionCollection and implies(), as |
| 75 | + * used by ClassPathTest? |
| 76 | + */ |
| 77 | + final PropertyPermission readSystemProperty = |
| 78 | + new PropertyPermission("guava.concurrent.generate_cancellation_cause", "read"); |
| 79 | + SecurityManager disallowPropertySecurityManager = |
| 80 | + new SecurityManager() { |
| 81 | + @Override |
| 82 | + public void checkPermission(Permission p) { |
| 83 | + if (readSystemProperty.equals(p)) { |
| 84 | + throw new SecurityException("Disallowed: " + p); |
| 85 | + } |
| 86 | + } |
| 87 | + }; |
| 88 | + System.setSecurityManager(disallowPropertySecurityManager); |
| 89 | + |
| 90 | + settableFutureClass = classReloader.loadClass(SettableFuture.class.getName()); |
| 91 | + |
| 92 | + /* |
| 93 | + * We must keep the SecurityManager installed during the test body: It affects what kind of |
| 94 | + * threads ForkJoinPool.commonPool() creates. |
| 95 | + */ |
| 96 | + } |
| 97 | + |
| 98 | + @Override |
| 99 | + protected void tearDown() throws Exception { |
| 100 | + System.setSecurityManager(oldSecurityManager); |
| 101 | + classReloader.close(); |
| 102 | + Thread.currentThread().setContextClassLoader(oldClassLoader); |
| 103 | + } |
| 104 | + |
| 105 | + public void testAbstractFutureInitializationWithInnocuousThread_doesNotThrow() throws Exception { |
| 106 | + CountDownLatch latch = new CountDownLatch(1); |
| 107 | + // Setting a security manager causes the common ForkJoinPool to use InnocuousThreads with no |
| 108 | + // permissions. |
| 109 | + // submit()/join() causes this thread to execute the task instead, so we use a CountDownLatch as |
| 110 | + // a barrier to synchronize. |
| 111 | + // TODO(cpovirk): If some other test already initialized commonPool(), this won't work :( |
| 112 | + // Maybe we should just run this test in its own VM. |
| 113 | + ForkJoinPool.commonPool() |
| 114 | + .execute( |
| 115 | + () -> { |
| 116 | + try { |
| 117 | + settableFutureClass.getMethod("create").invoke(null); |
| 118 | + latch.countDown(); |
| 119 | + } catch (Exception e) { |
| 120 | + throw new RuntimeException(e); |
| 121 | + } |
| 122 | + }); |
| 123 | + // In the failure case, await() will timeout. |
| 124 | + assertTrue(latch.await(2, TimeUnit.SECONDS)); |
| 125 | + } |
| 126 | + |
| 127 | + // TODO(cpovirk): Write a similar test that doesn't use ForkJoinPool (to run under Android)? |
| 128 | +} |
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