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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
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include <unistd.h>
#include <chrono>
#include <cstring>
#include <iostream>
#include <string>
#include <thread>
#include <vector>
#include <android-base/unique_fd.h>
namespace android {
namespace snapshot {
static constexpr uint32_t PACKET_SIZE = 512;
static constexpr char kSnapuserdSocket[] = "snapuserd";
// Ensure that the second-stage daemon for snapuserd is running.
bool EnsureSnapuserdStarted();
class SnapuserdClient {
android::base::unique_fd sockfd_;
bool Sendmsg(const std::string& msg);
std::string Receivemsg();
bool ValidateConnection();
explicit SnapuserdClient(android::base::unique_fd&& sockfd);
static std::unique_ptr<SnapuserdClient> Connect(const std::string& socket_name,
std::chrono::milliseconds timeout_ms);
bool StopSnapuserd();
// Initializing a snapuserd handler is a three-step process:
// 1. Client invokes InitDmUserCow. This creates the snapuserd handler and validates the
// COW. The number of sectors required for the dm-user target is returned.
// 2. Client creates the device-mapper device with the dm-user target.
// 3. Client calls AttachControlDevice.
// The misc_name must be the "misc_name" given to dm-user in step 2.
uint64_t InitDmUserCow(const std::string& misc_name, const std::string& cow_device,
const std::string& backing_device);
bool AttachDmUser(const std::string& misc_name);
// Wait for snapuserd to disassociate with a dm-user control device. This
// must ONLY be called if the control device has already been deleted.
bool WaitForDeviceDelete(const std::string& control_device);
// Detach snapuserd. This shuts down the listener socket, and will cause
// snapuserd to gracefully exit once all handler threads have terminated.
// This should only be used on first-stage instances of snapuserd.
bool DetachSnapuserd();
} // namespace snapshot
} // namespace android