lshal: Add timeout for IPC calls.
IPC calls into interfaces should be done fault-torelently.
Add a timeout for each IPC call made so that lshal won't be
indefinitely blocked even if the interface don't reply
promptly.
Bug: 35317039
Test: lshal
Change-Id: Icb8157716ad68bddb5b33304b9063aa6f233985d
diff --git a/cmds/lshal/Timeout.h b/cmds/lshal/Timeout.h
new file mode 100644
index 0000000..bf883c0
--- /dev/null
+++ b/cmds/lshal/Timeout.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <condition_variable>
+#include <chrono>
+#include <functional>
+#include <mutex>
+#include <thread>
+
+#include <hidl/Status.h>
+
+namespace android {
+namespace lshal {
+
+static constexpr std::chrono::milliseconds IPC_CALL_WAIT{500};
+
+class BackgroundTaskState {
+public:
+ BackgroundTaskState(){}
+ void notify() {
+ std::unique_lock<std::mutex> lock(mMutex);
+ mFinished = true;
+ lock.unlock();
+ mCondVar.notify_all();
+ }
+ template<class C, class D>
+ bool wait(std::chrono::time_point<C, D> end) {
+ std::unique_lock<std::mutex> lock(mMutex);
+ mCondVar.wait_until(lock, end, [this](){ return this->mFinished; });
+ return mFinished;
+ }
+private:
+ std::mutex mMutex;
+ std::condition_variable mCondVar;
+ bool mFinished = false;
+};
+
+template<class R, class P>
+bool timeout(std::chrono::duration<R, P> delay, const std::function<void(void)> &func) {
+ auto now = std::chrono::system_clock::now();
+ BackgroundTaskState state{};
+ std::thread t([&state, &func] {
+ func();
+ state.notify();
+ });
+ t.detach();
+ bool success = state.wait(now + delay);
+ return success;
+}
+
+template<class Function, class I, class... Args>
+typename std::result_of<Function(I *, Args...)>::type
+timeoutIPC(const sp<I> &interfaceObject, Function &&func, Args &&... args) {
+ using ::android::hardware::Status;
+ typename std::result_of<Function(I *, Args...)>::type ret{Status::ok()};
+ auto boundFunc = std::bind(std::forward<Function>(func),
+ interfaceObject.get(), std::forward<Args>(args)...);
+ bool success = timeout(IPC_CALL_WAIT, [&ret, &boundFunc] {
+ ret = boundFunc();
+ });
+ if (!success) {
+ return Status::fromStatusT(TIMED_OUT);
+ }
+ return ret;
+}
+
+} // namespace lshal
+} // namespace android