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// Copyright (C) 2020 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.
#pragma once
#include <poll.h>
#include <cstdio>
#include <cstring>
#include <functional>
#include <future>
#include <iostream>
#include <mutex>
#include <sstream>
#include <string>
#include <thread>
#include <vector>
#include <android-base/unique_fd.h>
#include "snapuserd.h"
namespace android {
namespace snapshot {
static constexpr uint32_t MAX_PACKET_SIZE = 512;
enum class DaemonOperations {
INIT,
START,
QUERY,
STOP,
DELETE,
DETACH,
INVALID,
};
class DmUserHandler {
public:
explicit DmUserHandler(std::shared_ptr<Snapuserd> snapuserd);
void FreeResources() {
// Each worker thread holds a reference to snapuserd.
// Clear them so that all the resources
// held by snapuserd is released
if (snapuserd_) {
snapuserd_->FreeResources();
snapuserd_ = nullptr;
}
}
const std::shared_ptr<Snapuserd>& snapuserd() const { return snapuserd_; }
std::thread& thread() { return thread_; }
const std::string& misc_name() const { return misc_name_; }
private:
std::thread thread_;
std::shared_ptr<Snapuserd> snapuserd_;
std::string misc_name_;
};
class Stoppable {
std::promise<void> exitSignal_;
std::future<void> futureObj_;
public:
Stoppable() : futureObj_(exitSignal_.get_future()) {}
virtual ~Stoppable() {}
bool StopRequested() {
// checks if value in future object is available
if (futureObj_.wait_for(std::chrono::milliseconds(0)) == std::future_status::timeout) {
return false;
}
return true;
}
// Request the thread to stop by setting value in promise object
void StopThreads() { exitSignal_.set_value(); }
};
class SnapuserdServer : public Stoppable {
private:
android::base::unique_fd sockfd_;
bool terminating_;
std::vector<struct pollfd> watched_fds_;
std::mutex lock_;
using HandlerList = std::vector<std::shared_ptr<DmUserHandler>>;
HandlerList dm_users_;
void AddWatchedFd(android::base::borrowed_fd fd);
void AcceptClient();
bool HandleClient(android::base::borrowed_fd fd, int revents);
bool Recv(android::base::borrowed_fd fd, std::string* data);
bool Sendmsg(android::base::borrowed_fd fd, const std::string& msg);
bool Receivemsg(android::base::borrowed_fd fd, const std::string& str);
void ShutdownThreads();
bool RemoveAndJoinHandler(const std::string& control_device);
DaemonOperations Resolveop(std::string& input);
std::string GetDaemonStatus();
void Parsemsg(std::string const& msg, const char delim, std::vector<std::string>& out);
bool IsTerminating() { return terminating_; }
void RunThread(std::shared_ptr<DmUserHandler> handler);
void JoinAllThreads();
// Find a DmUserHandler within a lock.
HandlerList::iterator FindHandler(std::lock_guard<std::mutex>* proof_of_lock,
const std::string& misc_name);
public:
SnapuserdServer() { terminating_ = false; }
~SnapuserdServer();
bool Start(const std::string& socketname);
bool Run();
void Interrupt();
std::shared_ptr<DmUserHandler> AddHandler(const std::string& misc_name,
const std::string& cow_device_path,
const std::string& backing_device);
bool StartHandler(const std::shared_ptr<DmUserHandler>& handler);
void SetTerminating() { terminating_ = true; }
};
} // namespace snapshot
} // namespace android
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