Support callback for rpc server

In case that a user want to be notified, a callback will be called after
setting up the RPC server.

Bug: 195381416
Test: atest MicrodroidHostTestCases
Test: run microdroid demo app
Change-Id: Ia98bfb879a434935d9708a6dcd4aa19c4d46ffe4

3 files changed, 18 insertions, 1 deletions

diff --git a/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp b/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
index 0309d6ca53..08f5eedacd 100644
--- a/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
+++ b/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
@@ -20,7 +20,16 @@ extern "C" {
 
 struct AIBinder;
 
+// Starts an RPC server on a given port and a given root IBinder object.
+// This function sets up the server and joins before returning.
 bool RunRpcServer(AIBinder* service, unsigned int port);
+
+// Starts an RPC server on a given port and a given root IBinder object.
+// This function sets up the server, calls readyCallback with a given param, and
+// then joins before returning.
+bool RunRpcServerCallback(AIBinder* service, unsigned int port, void (*readyCallback)(void* param),
+                          void* param);
+
 AIBinder* RpcClient(unsigned int cid, unsigned int port);
 
 // Connect to an RPC server with preconnected file descriptors.
diff --git a/libs/binder/libbinder_rpc_unstable.cpp b/libs/binder/libbinder_rpc_unstable.cpp
index 304415a7ce..cad55fb439 100644
--- a/libs/binder/libbinder_rpc_unstable.cpp
+++ b/libs/binder/libbinder_rpc_unstable.cpp
@@ -29,7 +29,8 @@ using android::base::unique_fd;
 
 extern "C" {
 
-bool RunRpcServer(AIBinder* service, unsigned int port) {
+bool RunRpcServerCallback(AIBinder* service, unsigned int port, void (*readyCallback)(void* param),
+                          void* param) {
     auto server = RpcServer::make();
     server->iUnderstandThisCodeIsExperimentalAndIWillNotUseItInProduction();
     if (status_t status = server->setupVsockServer(port); status != OK) {
@@ -38,6 +39,8 @@ bool RunRpcServer(AIBinder* service, unsigned int port) {
         return false;
     }
     server->setRootObject(AIBinder_toPlatformBinder(service));
+
+    if (readyCallback) readyCallback(param);
     server->join();
 
     // Shutdown any open sessions since server failed.
@@ -45,6 +48,10 @@ bool RunRpcServer(AIBinder* service, unsigned int port) {
     return true;
 }
 
+bool RunRpcServer(AIBinder* service, unsigned int port) {
+    return RunRpcServerCallback(service, port, nullptr, nullptr);
+}
+
 AIBinder* RpcClient(unsigned int cid, unsigned int port) {
     auto session = RpcSession::make();
     if (status_t status = session->setupVsockClient(cid, port); status != OK) {
diff --git a/libs/binder/libbinder_rpc_unstable.map.txt b/libs/binder/libbinder_rpc_unstable.map.txt
index 1138786a64..e8565695a3 100644
--- a/libs/binder/libbinder_rpc_unstable.map.txt
+++ b/libs/binder/libbinder_rpc_unstable.map.txt
@@ -1,6 +1,7 @@
 LIBBINDER_RPC_UNSTABLE_SHIM { # platform-only
   global:
     RunRpcServer;
+    RunRpcServerCallback;
     RpcClient;
     RpcPreconnectedClient;
   local: