Dynamically stop lazy services

Services can choose to register with the new LazyServiceRegistrar.
ServiceManager perpetually checks the reference counts of services
registered in this way. If ServiceManager detects that a service no
longer has any clients, it will notify the LazyServiceRegistrar, which
will attempt to shut down the service.

Bug: 143108344
Test: aidl_lazy_test
Change-Id: Ic01981b767ab4402e7aecdf1cdf9ed64df1f5af4

1 files changed, 22 insertions, 1 deletions

diff --git a/cmds/servicemanager/ServiceManager.h b/cmds/servicemanager/ServiceManager.h
index 7dcdaa4661..d3c89ee2ad 100644
--- a/cmds/servicemanager/ServiceManager.h
+++ b/cmds/servicemanager/ServiceManager.h
@@ -17,12 +17,14 @@
 #pragma once
 
 #include <android/os/BnServiceManager.h>
+#include <android/os/IClientCallback.h>
 #include <android/os/IServiceCallback.h>
 
 #include "Access.h"
 
 namespace android {
 
+using os::IClientCallback;
 using os::IServiceCallback;
 
 class ServiceManager : public os::BnServiceManager, public IBinder::DeathRecipient {
@@ -40,9 +42,13 @@ public:
                                             const sp<IServiceCallback>& callback) override;
     binder::Status unregisterForNotifications(const std::string& name,
                                               const sp<IServiceCallback>& callback) override;
-    binder::Status isDeclared(const std::string& name, bool* outReturn) override;
 
+    binder::Status isDeclared(const std::string& name, bool* outReturn) override;
+    binder::Status registerClientCallback(const std::string& name, const sp<IBinder>& service,
+                                          const sp<IClientCallback>& cb) override;
+    binder::Status tryUnregisterService(const std::string& name, const sp<IBinder>& binder) override;
     void binderDied(const wp<IBinder>& who) override;
+    void handleClientCallbacks();
 
 protected:
     virtual void tryStartService(const std::string& name);
@@ -52,9 +58,16 @@ private:
         sp<IBinder> binder; // not null
         bool allowIsolated;
         int32_t dumpPriority;
+        bool hasClients = false; // notifications sent on true -> false.
+        bool guaranteeClient = false; // forces the client check to true
+        pid_t debugPid = 0; // the process in which this service runs
+
+        // the number of clients of the service, including servicemanager itself
+        ssize_t getNodeStrongRefCount();
     };
 
     using CallbackMap = std::map<std::string, std::vector<sp<IServiceCallback>>>;
+    using ClientCallbackMap = std::map<std::string, std::vector<sp<IClientCallback>>>;
     using ServiceMap = std::map<std::string, Service>;
 
     // removes a callback from mNameToCallback, removing it if the vector is empty
@@ -62,10 +75,18 @@ private:
     void removeCallback(const wp<IBinder>& who,
                         CallbackMap::iterator* it,
                         bool* found);
+    ssize_t handleServiceClientCallback(const std::string& serviceName);
+     // Also updates mHasClients (of what the last callback was)
+    void sendClientCallbackNotifications(const std::string& serviceName, bool hasClients);
+    // removes a callback from mNameToClientCallback, deleting the entry if the vector is empty
+    // this updates the iterator to the next location
+    void removeClientCallback(const wp<IBinder>& who, ClientCallbackMap::iterator* it);
+
     sp<IBinder> tryGetService(const std::string& name, bool startIfNotFound);
 
     CallbackMap mNameToCallback;
     ServiceMap mNameToService;
+    ClientCallbackMap mNameToClientCallback;
 
     std::unique_ptr<Access> mAccess;
 };