Add a cache to getService with invalidation

Test: atest binderCacheUnitTest
Bug: 333854840
Flag: LIBBINDER_CLIENT_CACHE
Change-Id: I1b4e8482817c422850aed7359beaf7174b55445e
diff --git a/libs/binder/tests/binderCacheUnitTest.cpp b/libs/binder/tests/binderCacheUnitTest.cpp
new file mode 100644
index 0000000..92dab19
--- /dev/null
+++ b/libs/binder/tests/binderCacheUnitTest.cpp
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2024 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.
+ */
+#include <gtest/gtest.h>
+
+#include <android-base/logging.h>
+#include <android/os/IServiceManager.h>
+#include <binder/IBinder.h>
+#include <binder/IPCThreadState.h>
+#include <binder/IServiceManager.h>
+#include <binder/IServiceManagerUnitTestHelper.h>
+#include "fakeservicemanager/FakeServiceManager.h"
+
+#include <sys/prctl.h>
+#include <thread>
+
+using namespace android;
+
+#ifdef LIBBINDER_CLIENT_CACHE
+constexpr bool kUseLibbinderCache = true;
+#else
+constexpr bool kUseLibbinderCache = false;
+#endif
+
+// A service name which is in the static list of cachable services
+const String16 kCachedServiceName = String16("isub");
+
+#define EXPECT_OK(status)                 \
+    do {                                  \
+        binder::Status stat = (status);   \
+        EXPECT_TRUE(stat.isOk()) << stat; \
+    } while (false)
+
+const String16 kServerName = String16("binderCacheUnitTest");
+
+class FooBar : public BBinder {
+public:
+    status_t onTransact(uint32_t, const Parcel&, Parcel*, uint32_t) {
+        // exit the server
+        std::thread([] { exit(EXIT_FAILURE); }).detach();
+        return OK;
+    }
+    void killServer(sp<IBinder> binder) {
+        Parcel data, reply;
+        binder->transact(0, data, &reply, 0);
+    }
+};
+
+class MockAidlServiceManager : public os::IServiceManagerDefault {
+public:
+    MockAidlServiceManager() : innerSm() {}
+
+    binder::Status checkService(const ::std::string& name, os::Service* _out) override {
+        sp<IBinder> binder = innerSm.getService(String16(name.c_str()));
+        *_out = os::Service::make<os::Service::Tag::binder>(binder);
+        return binder::Status::ok();
+    }
+
+    binder::Status addService(const std::string& name, const sp<IBinder>& service,
+                              bool allowIsolated, int32_t dumpPriority) override {
+        return binder::Status::fromStatusT(
+                innerSm.addService(String16(name.c_str()), service, allowIsolated, dumpPriority));
+    }
+
+    FakeServiceManager innerSm;
+};
+
+class LibbinderCacheTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        sp<MockAidlServiceManager> sm = sp<MockAidlServiceManager>::make();
+        mServiceManager = getServiceManagerShimFromAidlServiceManagerForTests(sm);
+    }
+
+    void TearDown() override {}
+
+public:
+    void cacheAndConfirmCacheHit(const sp<IBinder>& binder1, const sp<IBinder>& binder2) {
+        // Add a service
+        EXPECT_EQ(OK, mServiceManager->addService(kCachedServiceName, binder1));
+        // Get the service. This caches it.
+        sp<IBinder> result = mServiceManager->checkService(kCachedServiceName);
+        ASSERT_EQ(binder1, result);
+
+        // Add the different binder and replace the service.
+        // The cache should still hold the original binder.
+        EXPECT_EQ(OK, mServiceManager->addService(kCachedServiceName, binder2));
+
+        result = mServiceManager->checkService(kCachedServiceName);
+        if (kUseLibbinderCache) {
+            // If cache is enabled, we should get the binder to Service Manager.
+            EXPECT_EQ(binder1, result);
+        } else {
+            // If cache is disabled, then we should get the newer binder
+            EXPECT_EQ(binder2, result);
+        }
+    }
+
+    sp<android::IServiceManager> mServiceManager;
+};
+
+TEST_F(LibbinderCacheTest, AddLocalServiceAndConfirmCacheHit) {
+    sp<IBinder> binder1 = sp<BBinder>::make();
+    sp<IBinder> binder2 = sp<BBinder>::make();
+
+    cacheAndConfirmCacheHit(binder1, binder2);
+}
+
+TEST_F(LibbinderCacheTest, AddRemoteServiceAndConfirmCacheHit) {
+    sp<IBinder> binder1 = defaultServiceManager()->checkService(kServerName);
+    ASSERT_NE(binder1, nullptr);
+    sp<IBinder> binder2 = IInterface::asBinder(mServiceManager);
+
+    cacheAndConfirmCacheHit(binder1, binder2);
+}
+
+TEST_F(LibbinderCacheTest, RemoveFromCacheOnServerDeath) {
+    sp<IBinder> binder1 = defaultServiceManager()->checkService(kServerName);
+    FooBar foo = FooBar();
+
+    EXPECT_EQ(OK, mServiceManager->addService(kCachedServiceName, binder1));
+
+    // Check Service, this caches the binder
+    sp<IBinder> result = mServiceManager->checkService(kCachedServiceName);
+    ASSERT_EQ(binder1, result);
+
+    // Kill the server, this should remove from cache.
+    foo.killServer(binder1);
+    pid_t pid;
+    ASSERT_EQ(OK, binder1->getDebugPid(&pid));
+    system(("kill -9 " + std::to_string(pid)).c_str());
+
+    sp<IBinder> binder2 = sp<BBinder>::make();
+
+    // Add new service with the same name.
+    // This will replace the service in FakeServiceManager.
+    EXPECT_EQ(OK, mServiceManager->addService(kCachedServiceName, binder2));
+
+    // Confirm that new service is returned instead of old.
+    sp<IBinder> result2 = mServiceManager->checkService(kCachedServiceName);
+    ASSERT_EQ(binder2, result2);
+}
+
+TEST_F(LibbinderCacheTest, NullBinderNotCached) {
+    sp<IBinder> binder1 = nullptr;
+    sp<IBinder> binder2 = sp<BBinder>::make();
+
+    // Check for a cacheble service which isn't registered.
+    // FakeServiceManager should return nullptr.
+    // This shouldn't be cached.
+    sp<IBinder> result = mServiceManager->checkService(kCachedServiceName);
+    ASSERT_EQ(binder1, result);
+
+    // Add the same service
+    EXPECT_EQ(OK, mServiceManager->addService(kCachedServiceName, binder2));
+
+    // This should return the newly added service.
+    result = mServiceManager->checkService(kCachedServiceName);
+    EXPECT_EQ(binder2, result);
+}
+
+TEST_F(LibbinderCacheTest, DoNotCacheServiceNotInList) {
+    sp<IBinder> binder1 = sp<BBinder>::make();
+    sp<IBinder> binder2 = sp<BBinder>::make();
+    String16 serviceName = String16("NewLibbinderCacheTest");
+    // Add a service
+    EXPECT_EQ(OK, mServiceManager->addService(serviceName, binder1));
+    // Get the service. This shouldn't caches it.
+    sp<IBinder> result = mServiceManager->checkService(serviceName);
+    ASSERT_EQ(binder1, result);
+
+    // Add the different binder and replace the service.
+    EXPECT_EQ(OK, mServiceManager->addService(serviceName, binder2));
+
+    // Confirm that we get the new service
+    result = mServiceManager->checkService(serviceName);
+    EXPECT_EQ(binder2, result);
+}
+
+int main(int argc, char** argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+
+    if (fork() == 0) {
+        prctl(PR_SET_PDEATHSIG, SIGHUP);
+
+        // Start a FooBar service and add it to the servicemanager.
+        sp<IBinder> server = new FooBar();
+        defaultServiceManager()->addService(kServerName, server);
+
+        IPCThreadState::self()->joinThreadPool(true);
+        exit(1); // should not reach
+    }
+
+    status_t err = ProcessState::self()->setThreadPoolMaxThreadCount(3);
+    ProcessState::self()->startThreadPool();
+    CHECK_EQ(ProcessState::self()->isThreadPoolStarted(), true);
+    CHECK_GT(ProcessState::self()->getThreadPoolMaxTotalThreadCount(), 0);
+
+    auto binder = defaultServiceManager()->waitForService(kServerName);
+    CHECK_NE(nullptr, binder.get());
+    return RUN_ALL_TESTS();
+}