libbinder: RpcSession exposes sp<RpcServer>
This object guarantees a strong pointer IFF it is associated with a
server. The wp<> return type here previously was for convenience (idk?)
but users of it shouldn't be concerned with the underlying memory
situation.
Bug: 167966510
Test: binderRpcTest
Change-Id: I6578c3a4246e1bd07f7697c11d4b56899b50245b
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index 3dbd11f..f953a05 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -312,8 +312,13 @@
}
}
-wp<RpcServer> RpcSession::server() {
- return mForServer;
+sp<RpcServer> RpcSession::server() {
+ RpcServer* unsafeServer = mForServer.unsafe_get();
+ sp<RpcServer> server = mForServer.promote();
+
+ LOG_ALWAYS_FATAL_IF((unsafeServer == nullptr) != (server == nullptr),
+ "wp<> is to avoid strong cycle only");
+ return server;
}
bool RpcSession::setupSocketClient(const RpcSocketAddress& addr) {
diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index 8dd6daf..9676109 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -741,7 +741,7 @@
break;
}
default: {
- sp<RpcServer> server = session->server().promote();
+ sp<RpcServer> server = session->server();
if (server) {
switch (transaction->code) {
case RPC_SPECIAL_TRANSACT_GET_ROOT: {
diff --git a/libs/binder/include/binder/RpcSession.h b/libs/binder/include/binder/RpcSession.h
index eaa86dd..218de20 100644
--- a/libs/binder/include/binder/RpcSession.h
+++ b/libs/binder/include/binder/RpcSession.h
@@ -118,7 +118,11 @@
~RpcSession();
- wp<RpcServer> server();
+ /**
+ * Server if this session is created as part of a server (symmetrical to
+ * client servers). Otherwise, nullptr.
+ */
+ sp<RpcServer> server();
// internal only
const std::unique_ptr<RpcState>& state() { return mState; }