7205c62933
A previous change moved property_service into its own thread, since there was otherwise a deadlock whenever a process called by init would try to set a property. This new thread, however, would send a message via a blocking socket to init for each property that it received, since init may need to take action depending on which property it is. Unfortunately, this means that the deadlock is still possible, the only difference is the socket's buffer must be filled before init deadlocks. There are possible partial solutions here: the socket's buffer may be increased or property_service may only send messages for the properties that init will take action on, however all of these solutions still lead to eventual deadlock. The only complete solution is to handle these messages asynchronously. This change, therefore, adds the following: 1) A lock for instructing init to reboot 2) A lock for waiting on properties 3) A lock for queueing new properties 4) A lock for any actions with ServiceList or any Services, enforced through thread annotations, particularly since this code was not designed with the intention of being multi-threaded. Bug: 146877356 Bug: 148236233 Test: boot Test: kill hwservicemanager without deadlock Change-Id: I84108e54217866205a48c45e8b59355012c32ea8
62 lines
1.8 KiB
C++
62 lines
1.8 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <mutex>
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#include <string>
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#include <vector>
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#include <android-base/thread_annotations.h>
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#include "action.h"
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#include "builtins.h"
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namespace android {
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namespace init {
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class ActionManager {
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public:
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static ActionManager& GetInstance();
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// Exposed for testing
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ActionManager();
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size_t CheckAllCommands();
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void AddAction(std::unique_ptr<Action> action);
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void QueueEventTrigger(const std::string& trigger);
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void QueuePropertyChange(const std::string& name, const std::string& value);
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void QueueAllPropertyActions();
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void QueueBuiltinAction(BuiltinFunction func, const std::string& name);
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void ExecuteOneCommand();
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bool HasMoreCommands() const;
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void DumpState() const;
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void ClearQueue();
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private:
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ActionManager(ActionManager const&) = delete;
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void operator=(ActionManager const&) = delete;
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std::vector<std::unique_ptr<Action>> actions_;
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std::queue<std::variant<EventTrigger, PropertyChange, BuiltinAction>> event_queue_
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GUARDED_BY(event_queue_lock_);
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mutable std::mutex event_queue_lock_;
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std::queue<const Action*> current_executing_actions_;
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std::size_t current_command_;
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};
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} // namespace init
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} // namespace android
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