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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 <linux/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <csignal>
#include <cstring>
#include <iostream>
#include <limits>
#include <map>
#include <string>
#include <thread>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.h>
#include <libdm/dm.h>
#include <libsnapshot/cow_reader.h>
#include <libsnapshot/cow_writer.h>
#include <libsnapshot/snapuserd_kernel.h>
namespace android {
namespace snapshot {
using android::base::unique_fd;
class BufferSink : public IByteSink {
void Initialize(size_t size);
void* GetBufPtr() { return buffer_.get(); }
void Clear() { memset(GetBufPtr(), 0, buffer_size_); }
void* GetPayloadBuffer(size_t size);
void* GetBuffer(size_t requested, size_t* actual) override;
void UpdateBufferOffset(size_t size) { buffer_offset_ += size; }
struct dm_user_header* GetHeaderPtr();
bool ReturnData(void*, size_t) override { return true; }
void ResetBufferOffset() { buffer_offset_ = 0; }
std::unique_ptr<uint8_t[]> buffer_;
loff_t buffer_offset_;
size_t buffer_size_;
class Snapuserd final {
Snapuserd(const std::string& misc_name, const std::string& cow_device,
const std::string& backing_device);
bool InitBackingAndControlDevice();
bool InitCowDevice();
bool Run();
const std::string& GetControlDevicePath() { return control_device_; }
const std::string& GetMiscName() { return misc_name_; }
uint64_t GetNumSectors() { return num_sectors_; }
bool IsAttached() const { return ctrl_fd_ >= 0; }
bool DmuserReadRequest();
bool DmuserWriteRequest();
bool ReadDmUserHeader();
bool ReadDmUserPayload(void* buffer, size_t size);
bool WriteDmUserPayload(size_t size);
void ConstructKernelCowHeader();
bool ReadMetadata();
bool ZerofillDiskExceptions(size_t read_size);
bool ReadDiskExceptions(chunk_t chunk, size_t size);
int ReadUnalignedSector(sector_t sector, size_t size,
std::map<sector_t, const CowOperation*>::iterator& it);
int ReadData(sector_t sector, size_t size);
bool IsChunkIdMetadata(chunk_t chunk);
chunk_t GetNextAllocatableChunkId(chunk_t chunk_id);
bool ProcessCowOp(const CowOperation* cow_op);
bool ProcessReplaceOp(const CowOperation* cow_op);
bool ProcessCopyOp(const CowOperation* cow_op);
bool ProcessZeroOp();
loff_t GetMergeStartOffset(void* merged_buffer, void* unmerged_buffer,
int* unmerged_exceptions);
int GetNumberOfMergedOps(void* merged_buffer, void* unmerged_buffer, loff_t offset,
int unmerged_exceptions, bool* copy_op);
bool ProcessMergeComplete(chunk_t chunk, void* buffer);
sector_t ChunkToSector(chunk_t chunk) { return chunk << CHUNK_SHIFT; }
chunk_t SectorToChunk(sector_t sector) { return sector >> CHUNK_SHIFT; }
bool IsBlockAligned(int read_size) { return ((read_size & (BLOCK_SIZE - 1)) == 0); }
std::string cow_device_;
std::string backing_store_device_;
std::string control_device_;
std::string misc_name_;
unique_fd cow_fd_;
unique_fd backing_store_fd_;
unique_fd ctrl_fd_;
uint32_t exceptions_per_area_;
uint64_t num_sectors_;
std::unique_ptr<ICowOpIter> cowop_iter_;
std::unique_ptr<ICowOpReverseIter> cowop_riter_;
std::unique_ptr<CowReader> reader_;
std::unique_ptr<CowWriter> writer_;
// Vector of disk exception which is a
// mapping of old-chunk to new-chunk
std::vector<std::unique_ptr<uint8_t[]>> vec_;
// Key - Sector
// Value - cow operation
// chunk_map stores the pseudo mapping of sector
// to COW operations. Each COW op is 4k; however,
// we can get a read request which are as small
// as 512 bytes. Hence, we need to binary search
// in the chunk_map to find the nearest COW op.
std::map<sector_t, const CowOperation*> chunk_map_;
bool metadata_read_done_ = false;
BufferSink bufsink_;
} // namespace snapshot
} // namespace android