libbinder_ndk: Add APIs for lazy services
Add a way to register a lazy service, wait for the service, and check if
it was declared in vintf manifest.
Test: atest libbinder_ndk_unit_test
Bug: 149794667
Change-Id: I97f83de35ed7dd4923812c66ee6106b396e89031
diff --git a/libs/binder/ndk/include_platform/android/binder_manager.h b/libs/binder/ndk/include_platform/android/binder_manager.h
index 055c79b..52bcd20 100644
--- a/libs/binder/ndk/include_platform/android/binder_manager.h
+++ b/libs/binder/ndk/include_platform/android/binder_manager.h
@@ -18,6 +18,7 @@
#include <android/binder_ibinder.h>
#include <android/binder_status.h>
+#include <sys/cdefs.h>
__BEGIN_DECLS
@@ -50,4 +51,47 @@
*/
__attribute__((warn_unused_result)) AIBinder* AServiceManager_getService(const char* instance);
+/**
+ * Registers a lazy service with the default service manager under the 'instance' name.
+ * Does not take ownership of binder.
+ * The service must be configured statically with init so it can be restarted with
+ * ctl.interface.* messages from servicemanager.
+ * AServiceManager_registerLazyService cannot safely be used with AServiceManager_addService
+ * in the same process. If one service is registered with AServiceManager_registerLazyService,
+ * the entire process will have its lifetime controlled by servicemanager.
+ * Instead, all services in the process should be registered using
+ * AServiceManager_registerLazyService.
+ *
+ * \param binder object to register globally with the service manager.
+ * \param instance identifier of the service. This will be used to lookup the service.
+ *
+ * \return STATUS_OK on success.
+ */
+binder_status_t AServiceManager_registerLazyService(AIBinder* binder, const char* instance)
+ __INTRODUCED_IN(31);
+
+/**
+ * Gets a binder object with this specific instance name. Efficiently waits for the service.
+ * If the service is not declared, it will wait indefinitely. Requires the threadpool
+ * to be started in the service.
+ * This also implicitly calls AIBinder_incStrong (so the caller of this function is responsible
+ * for calling AIBinder_decStrong).
+ *
+ * \param instance identifier of the service used to lookup the service.
+ *
+ * \return service if registered, null if not.
+ */
+__attribute__((warn_unused_result)) AIBinder* AServiceManager_waitForService(const char* instance)
+ __INTRODUCED_IN(31);
+
+/**
+ * Check if a service is declared (e.g. VINTF manifest).
+ *
+ * \param instance identifier of the service.
+ *
+ * \return true on success, meaning AServiceManager_waitForService should always
+ * be able to return the service.
+ */
+bool AServiceManager_isDeclared(const char* instance) __INTRODUCED_IN(31);
+
__END_DECLS
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index d435382..1701fb5 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -117,6 +117,9 @@
ABinderProcess_setupPolling; # apex
AIBinder_getCallingSid; # apex
AIBinder_setRequestingSid; # apex
+ AServiceManager_isDeclared; # apex llndk
+ AServiceManager_registerLazyService; # llndk
+ AServiceManager_waitForService; # apex llndk
};
LIBBINDER_NDK_PLATFORM {
diff --git a/libs/binder/ndk/service_manager.cpp b/libs/binder/ndk/service_manager.cpp
index d0b166d..6b2184e 100644
--- a/libs/binder/ndk/service_manager.cpp
+++ b/libs/binder/ndk/service_manager.cpp
@@ -20,6 +20,7 @@
#include "status_internal.h"
#include <binder/IServiceManager.h>
+#include <binder/LazyServiceRegistrar.h>
using ::android::defaultServiceManager;
using ::android::IBinder;
@@ -61,3 +62,33 @@
AIBinder_incStrong(ret.get());
return ret.get();
}
+binder_status_t AServiceManager_registerLazyService(AIBinder* binder, const char* instance) {
+ if (binder == nullptr || instance == nullptr) {
+ return STATUS_UNEXPECTED_NULL;
+ }
+
+ auto serviceRegistrar = android::binder::LazyServiceRegistrar::getInstance();
+ status_t status = serviceRegistrar.registerService(binder->getBinder(), instance);
+
+ return PruneStatusT(status);
+}
+AIBinder* AServiceManager_waitForService(const char* instance) {
+ if (instance == nullptr) {
+ return nullptr;
+ }
+
+ sp<IServiceManager> sm = defaultServiceManager();
+ sp<IBinder> binder = sm->waitForService(String16(instance));
+
+ sp<AIBinder> ret = ABpBinder::lookupOrCreateFromBinder(binder);
+ AIBinder_incStrong(ret.get());
+ return ret.get();
+}
+bool AServiceManager_isDeclared(const char* instance) {
+ if (instance == nullptr) {
+ return false;
+ }
+
+ sp<IServiceManager> sm = defaultServiceManager();
+ return sm->isDeclared(String16(instance));
+}
diff --git a/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp b/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
index 9b2fcf0..332b4ca 100644
--- a/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
+++ b/libs/binder/ndk/tests/libbinder_ndk_unit_test.cpp
@@ -43,6 +43,7 @@
constexpr char kExistingNonNdkService[] = "SurfaceFlinger";
constexpr char kBinderNdkUnitTestService[] = "BinderNdkUnitTest";
+constexpr char kLazyBinderNdkUnitTestService[] = "LazyBinderNdkUnitTest";
class MyBinderNdkUnitTest : public aidl::BnBinderNdkUnitTest {
ndk::ScopedAStatus repeatInt(int32_t in, int32_t* out) {
@@ -143,6 +144,27 @@
return 1;
}
+int lazyService(const char* instance) {
+ ABinderProcess_setThreadPoolMaxThreadCount(0);
+ // Wait to register this service to make sure the main test process will
+ // actually wait for the service to be available. Tested with sleep(60),
+ // and reduced for sake of time.
+ sleep(1);
+ // Strong reference to MyBinderNdkUnitTest kept by service manager.
+ // This is just for testing, it has no corresponding init behavior.
+ auto service = ndk::SharedRefBase::make<MyBinderNdkUnitTest>();
+ auto binder = service->asBinder();
+
+ binder_status_t status = AServiceManager_registerLazyService(binder.get(), instance);
+ if (status != STATUS_OK) {
+ LOG(FATAL) << "Could not register: " << status << " " << instance;
+ }
+
+ ABinderProcess_joinThreadPool();
+
+ return 1; // should not return
+}
+
// This is too slow
// TEST(NdkBinder, GetServiceThatDoesntExist) {
// sp<IFoo> foo = IFoo::getService("asdfghkl;");
@@ -171,6 +193,33 @@
EXPECT_EQ(2, out);
}
+TEST(NdkBinder, GetLazyService) {
+ // Not declared in the vintf manifest
+ ASSERT_FALSE(AServiceManager_isDeclared(kLazyBinderNdkUnitTestService));
+ ndk::SpAIBinder binder(AServiceManager_waitForService(kLazyBinderNdkUnitTestService));
+ std::shared_ptr<aidl::IBinderNdkUnitTest> service =
+ aidl::IBinderNdkUnitTest::fromBinder(binder);
+ ASSERT_NE(service, nullptr);
+
+ EXPECT_EQ(STATUS_OK, AIBinder_ping(binder.get()));
+}
+
+// This is too slow
+TEST(NdkBinder, CheckLazyServiceShutDown) {
+ ndk::SpAIBinder binder(AServiceManager_waitForService(kLazyBinderNdkUnitTestService));
+ std::shared_ptr<aidl::IBinderNdkUnitTest> service =
+ aidl::IBinderNdkUnitTest::fromBinder(binder);
+ ASSERT_NE(service, nullptr);
+
+ EXPECT_EQ(STATUS_OK, AIBinder_ping(binder.get()));
+ binder = nullptr;
+ service = nullptr;
+ IPCThreadState::self()->flushCommands();
+ // Make sure the service is dead after some time of no use
+ sleep(10);
+ ASSERT_EQ(nullptr, AServiceManager_checkService(kLazyBinderNdkUnitTestService));
+}
+
void LambdaOnDeath(void* cookie) {
auto onDeath = static_cast<std::function<void(void)>*>(cookie);
(*onDeath)();
@@ -477,6 +526,10 @@
}
if (fork() == 0) {
prctl(PR_SET_PDEATHSIG, SIGHUP);
+ return lazyService(kLazyBinderNdkUnitTestService);
+ }
+ if (fork() == 0) {
+ prctl(PR_SET_PDEATHSIG, SIGHUP);
return generatedService();
}