commit 143a10dba6f492f0307b54f8d5e1e7e26bc887f1
author Jon Spivack <spivack@google.com> Tue Oct 27 19:29:14 2020 -0700
committer Jon Spivack <spivack@google.com> Fri Nov 06 03:08:14 2020 +0000
tree 95f29885cdcd4e67309cbb040aca9be5055d2e1c
parent 16524d223af41125713bd0e0ada84b84bad1b5c8

libbinder: Add ClientCounterCallbackImpl to LazyServiceRegistrar

This extra layer of indirection below ClientCounterCallback fixes a shared pointer ownership issue between LazyServiceRegistrar and ServiceManager. It also allows for implementation changes (like this one) without changing headers and breaking VNDK.

Bug: 170212632
Test: Manual (Went through reproduction steps in bug on rvc-dev)
Test: atest aidl_lazy_test
Change-Id: I4164a6d44e567c752726953e85aee0e91c6b525e
(cherry picked from commit e31d33a397507069a4333396f999bb33a1a9fb70)
Merged-In: I4164a6d44e567c752726953e85aee0e91c6b525e

libs/binder/LazyServiceRegistrar.cpp

diff --git a/libs/binder/LazyServiceRegistrar.cpp b/libs/binder/LazyServiceRegistrar.cpp
index 325e204..2e15e50 100644
--- a/libs/binder/LazyServiceRegistrar.cpp
+++ b/libs/binder/LazyServiceRegistrar.cpp
@@ -29,16 +29,12 @@
 
 using AidlServiceManager = android::os::IServiceManager;
 
-class ClientCounterCallback : public ::android::os::BnClientCallback {
+class ClientCounterCallbackImpl : public ::android::os::BnClientCallback {
 public:
-    ClientCounterCallback() : mNumConnectedServices(0), mForcePersist(false) {}
+    ClientCounterCallbackImpl() : mNumConnectedServices(0), mForcePersist(false) {}
 
     bool registerService(const sp<IBinder>& service, const std::string& name,
                          bool allowIsolated, int dumpFlags);
-
-    /**
-     * Set a flag to prevent services from automatically shutting down
-     */
     void forcePersist(bool persist);
 
 protected:
@@ -75,7 +71,23 @@
     bool mForcePersist;
 };
 
-bool ClientCounterCallback::registerService(const sp<IBinder>& service, const std::string& name,
+class ClientCounterCallback {
+public:
+    ClientCounterCallback();
+
+    bool registerService(const sp<IBinder>& service, const std::string& name,
+                                            bool allowIsolated, int dumpFlags);
+
+    /**
+     * Set a flag to prevent services from automatically shutting down
+     */
+    void forcePersist(bool persist);
+
+private:
+    sp<ClientCounterCallbackImpl> mImpl;
+};
+
+bool ClientCounterCallbackImpl::registerService(const sp<IBinder>& service, const std::string& name,
                                             bool allowIsolated, int dumpFlags) {
     auto manager = interface_cast<AidlServiceManager>(asBinder(defaultServiceManager()));
 
@@ -89,7 +101,7 @@
     }
 
     if (!reRegister) {
-        if (!manager->registerClientCallback(name, service, this).isOk()) {
+        if(!manager->registerClientCallback(name, service, this).isOk()) {
             ALOGE("Failed to add client callback for service %s", name.c_str());
             return false;
         }
@@ -105,7 +117,7 @@
     return true;
 }
 
-std::map<std::string, ClientCounterCallback::Service>::iterator ClientCounterCallback::assertRegisteredService(const sp<IBinder>& service) {
+std::map<std::string, ClientCounterCallbackImpl::Service>::iterator ClientCounterCallbackImpl::assertRegisteredService(const sp<IBinder>& service) {
     LOG_ALWAYS_FATAL_IF(service == nullptr, "Got onClients callback for null service");
     for (auto it = mRegisteredServices.begin(); it != mRegisteredServices.end(); ++it) {
         auto const& [name, registered] = *it;
@@ -117,7 +129,7 @@
     __builtin_unreachable();
 }
 
-void ClientCounterCallback::forcePersist(bool persist) {
+void ClientCounterCallbackImpl::forcePersist(bool persist) {
     mForcePersist = persist;
     if(!mForcePersist) {
         // Attempt a shutdown in case the number of clients hit 0 while the flag was on
@@ -129,7 +141,7 @@
  * onClients is oneway, so no need to worry about multi-threading. Note that this means multiple
  * invocations could occur on different threads however.
  */
-Status ClientCounterCallback::onClients(const sp<IBinder>& service, bool clients) {
+Status ClientCounterCallbackImpl::onClients(const sp<IBinder>& service, bool clients) {
     auto & [name, registered] = *assertRegisteredService(service);
     if (registered.clients == clients) {
         LOG_ALWAYS_FATAL("Process already thought %s had clients: %d but servicemanager has "
@@ -154,7 +166,7 @@
     return Status::ok();
 }
 
-void ClientCounterCallback::tryShutdown() {
+void ClientCounterCallbackImpl::tryShutdown() {
     if(mNumConnectedServices > 0) {
         // Should only shut down if there are no clients
         return;
@@ -175,7 +187,6 @@
 
         bool success = manager->tryUnregisterService(entry.first, entry.second.service).isOk();
 
-
         if (!success) {
             ALOGI("Failed to unregister service %s", entry.first.c_str());
             break;
@@ -200,6 +211,19 @@
     }
 }
 
+ClientCounterCallback::ClientCounterCallback() {
+      mImpl = sp<ClientCounterCallbackImpl>::make();
+}
+
+bool ClientCounterCallback::registerService(const sp<IBinder>& service, const std::string& name,
+                                            bool allowIsolated, int dumpFlags) {
+    return mImpl->registerService(service, name, allowIsolated, dumpFlags);
+}
+
+void ClientCounterCallback::forcePersist(bool persist) {
+    mImpl->forcePersist(persist);
+}
+
 }  // namespace internal
 
 LazyServiceRegistrar::LazyServiceRegistrar() {