Add support for preconnected RPC client
Normally we want to call RpcClient directly, but the apps don't have
access to create a client vsock themselves. This change adds a helper
function to establish an RPC session with preconnected file descriptor.
Bug: 195381416
Test: atest MicrodroidHostTestCases
Change-Id: Idbdc6b00ca459ed10b1c79e64f004708594b92da
diff --git a/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp b/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
index 7932d0f..0309d6c 100644
--- a/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
+++ b/libs/binder/include_rpc_unstable/binder_rpc_unstable.hpp
@@ -23,4 +23,13 @@
bool RunRpcServer(AIBinder* service, unsigned int port);
AIBinder* RpcClient(unsigned int cid, unsigned int port);
+// Connect to an RPC server with preconnected file descriptors.
+//
+// requestFd should connect to the server and return a valid file descriptor, or
+// -1 if connection fails.
+//
+// param will be passed to requestFd. Callers can use param to pass contexts to
+// the requestFd function.
+AIBinder* RpcPreconnectedClient(int (*requestFd)(void* param), void* param);
+
}
diff --git a/libs/binder/libbinder_rpc_unstable.cpp b/libs/binder/libbinder_rpc_unstable.cpp
index bcb13ae..304415a 100644
--- a/libs/binder/libbinder_rpc_unstable.cpp
+++ b/libs/binder/libbinder_rpc_unstable.cpp
@@ -15,6 +15,7 @@
*/
#include <android-base/logging.h>
+#include <android-base/unique_fd.h>
#include <android/binder_libbinder.h>
#include <binder/RpcServer.h>
#include <binder/RpcSession.h>
@@ -24,6 +25,7 @@
using android::RpcSession;
using android::status_t;
using android::statusToString;
+using android::base::unique_fd;
extern "C" {
@@ -52,4 +54,14 @@
}
return AIBinder_fromPlatformBinder(session->getRootObject());
}
+
+AIBinder* RpcPreconnectedClient(int (*requestFd)(void* param), void* param) {
+ auto session = RpcSession::make();
+ auto request = [=] { return unique_fd{requestFd(param)}; };
+ if (status_t status = session->setupPreconnectedClient(unique_fd{}, request); status != OK) {
+ LOG(ERROR) << "Failed to set up vsock client. error: " << statusToString(status).c_str();
+ return nullptr;
+ }
+ return AIBinder_fromPlatformBinder(session->getRootObject());
+}
}
diff --git a/libs/binder/libbinder_rpc_unstable.map.txt b/libs/binder/libbinder_rpc_unstable.map.txt
index 3921a4d..1138786 100644
--- a/libs/binder/libbinder_rpc_unstable.map.txt
+++ b/libs/binder/libbinder_rpc_unstable.map.txt
@@ -2,6 +2,7 @@
global:
RunRpcServer;
RpcClient;
+ RpcPreconnectedClient;
local:
*;
};