libbinder: add build option for single-threaded RPC
Trusty does not support threading. This adds a build option
to disable mutexes and other threading code from RpcState,
RpcSession, and RpcServer.
Bug: 224644083
Test: build Trusty
Change-Id: Iaa78caca1ddee45be7c2def2755598decc0d4d15
diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index f83bb5e..1cd1fd3 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -32,6 +32,7 @@
#include <log/log.h>
#include <utils/Compat.h>
+#include "BuildFlags.h"
#include "FdTrigger.h"
#include "RpcSocketAddress.h"
#include "RpcState.h"
@@ -131,27 +132,27 @@
}
void RpcServer::setRootObject(const sp<IBinder>& binder) {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
mRootObjectFactory = nullptr;
mRootObjectWeak = mRootObject = binder;
}
void RpcServer::setRootObjectWeak(const wp<IBinder>& binder) {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
mRootObject.clear();
mRootObjectFactory = nullptr;
mRootObjectWeak = binder;
}
void RpcServer::setPerSessionRootObject(
std::function<sp<IBinder>(const void*, size_t)>&& makeObject) {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
mRootObject.clear();
mRootObjectWeak.clear();
mRootObjectFactory = std::move(makeObject);
}
sp<IBinder> RpcServer::getRootObject() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
bool hasWeak = mRootObjectWeak.unsafe_get();
sp<IBinder> ret = mRootObjectWeak.promote();
ALOGW_IF(hasWeak && ret == nullptr, "RpcServer root object is freed, returning nullptr");
@@ -159,7 +160,7 @@
}
std::vector<uint8_t> RpcServer::getCertificate(RpcCertificateFormat format) {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
return mCtx->getCertificate(format);
}
@@ -168,15 +169,17 @@
}
void RpcServer::start() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
LOG_ALWAYS_FATAL_IF(mJoinThread.get(), "Already started!");
- mJoinThread = std::make_unique<std::thread>(&joinRpcServer, sp<RpcServer>::fromExisting(this));
+ mJoinThread =
+ std::make_unique<RpcMaybeThread>(&joinRpcServer, sp<RpcServer>::fromExisting(this));
+ rpcJoinIfSingleThreaded(*mJoinThread);
}
void RpcServer::join() {
{
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
LOG_ALWAYS_FATAL_IF(!mServer.ok(), "RpcServer must be setup to join.");
LOG_ALWAYS_FATAL_IF(mShutdownTrigger != nullptr, "Already joined");
mJoinThreadRunning = true;
@@ -204,24 +207,31 @@
LOG_RPC_DETAIL("accept4 on fd %d yields fd %d", mServer.get(), clientFd.get());
{
- std::lock_guard<std::mutex> _l(mLock);
- std::thread thread =
- std::thread(&RpcServer::establishConnection, sp<RpcServer>::fromExisting(this),
- std::move(clientFd), addr, addrLen);
- mConnectingThreads[thread.get_id()] = std::move(thread);
+ RpcMutexLockGuard _l(mLock);
+ RpcMaybeThread thread = RpcMaybeThread(&RpcServer::establishConnection,
+ sp<RpcServer>::fromExisting(this),
+ std::move(clientFd), addr, addrLen);
+
+ auto& threadRef = mConnectingThreads[thread.get_id()];
+ threadRef = std::move(thread);
+ rpcJoinIfSingleThreaded(threadRef);
}
}
LOG_RPC_DETAIL("RpcServer::join exiting with %s", statusToString(status).c_str());
- {
- std::lock_guard<std::mutex> _l(mLock);
+ if constexpr (kEnableRpcThreads) {
+ RpcMutexLockGuard _l(mLock);
mJoinThreadRunning = false;
+ } else {
+ // Multi-threaded builds clear this in shutdown(), but we need it valid
+ // so the loop above exits cleanly
+ mShutdownTrigger = nullptr;
}
mShutdownCv.notify_all();
}
bool RpcServer::shutdown() {
- std::unique_lock<std::mutex> _l(mLock);
+ RpcMutexUniqueLock _l(mLock);
if (mShutdownTrigger == nullptr) {
LOG_RPC_DETAIL("Cannot shutdown. No shutdown trigger installed (already shutdown?)");
return false;
@@ -232,10 +242,16 @@
for (auto& [id, session] : mSessions) {
(void)id;
// server lock is a more general lock
- std::lock_guard<std::mutex> _lSession(session->mMutex);
+ RpcMutexLockGuard _lSession(session->mMutex);
session->mShutdownTrigger->trigger();
}
+ if constexpr (!kEnableRpcThreads) {
+ // In single-threaded mode we're done here, everything else that
+ // needs to happen should be at the end of RpcServer::join()
+ return true;
+ }
+
while (mJoinThreadRunning || !mConnectingThreads.empty() || !mSessions.empty()) {
if (std::cv_status::timeout == mShutdownCv.wait_for(_l, std::chrono::seconds(1))) {
ALOGE("Waiting for RpcServer to shut down (1s w/o progress). Join thread running: %d, "
@@ -263,7 +279,7 @@
}
std::vector<sp<RpcSession>> RpcServer::listSessions() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
std::vector<sp<RpcSession>> sessions;
for (auto& [id, session] : mSessions) {
(void)id;
@@ -273,7 +289,7 @@
}
size_t RpcServer::numUninitializedSessions() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
return mConnectingThreads.size();
}
@@ -354,12 +370,12 @@
}
}
- std::thread thisThread;
+ RpcMaybeThread thisThread;
sp<RpcSession> session;
{
- std::unique_lock<std::mutex> _l(server->mLock);
+ RpcMutexUniqueLock _l(server->mLock);
- auto threadId = server->mConnectingThreads.find(std::this_thread::get_id());
+ auto threadId = server->mConnectingThreads.find(rpc_this_thread::get_id());
LOG_ALWAYS_FATAL_IF(threadId == server->mConnectingThreads.end(),
"Must establish connection on owned thread");
thisThread = std::move(threadId->second);
@@ -505,7 +521,7 @@
LOG_RPC_DETAIL("Dropping session with address %s",
base::HexString(id.data(), id.size()).c_str());
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
auto it = mSessions.find(id);
LOG_ALWAYS_FATAL_IF(it == mSessions.end(), "Bad state, unknown session id %s",
base::HexString(id.data(), id.size()).c_str());
@@ -519,17 +535,17 @@
}
bool RpcServer::hasServer() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
return mServer.ok();
}
unique_fd RpcServer::releaseServer() {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
return std::move(mServer);
}
status_t RpcServer::setupExternalServer(base::unique_fd serverFd) {
- std::lock_guard<std::mutex> _l(mLock);
+ RpcMutexLockGuard _l(mLock);
if (mServer.ok()) {
ALOGE("Each RpcServer can only have one server.");
return INVALID_OPERATION;