payload_consumer/verity_writer_android.h

//
// Copyright (C) 2018 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.
//

#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_VERITY_WRITER_ANDROID_H_
#define UPDATE_ENGINE_PAYLOAD_CONSUMER_VERITY_WRITER_ANDROID_H_

#include <memory>
#include <string>

#include <verity/hash_tree_builder.h>

#include "payload_consumer/file_descriptor.h"
#include "update_engine/payload_consumer/verity_writer_interface.h"

namespace chromeos_update_engine {

class VerityWriterAndroid : public VerityWriterInterface {
 public:
  VerityWriterAndroid() = default;
  ~VerityWriterAndroid() override = default;

  bool Init(const InstallPlan::Partition& partition);
  bool Update(uint64_t offset, const uint8_t* buffer, size_t size) override;
  bool Finalize(FileDescriptorPtr read_fd, FileDescriptorPtr write_fd) override;

  // Read [data_offset : data_offset + data_size) from |path| and encode FEC
  // data, if |verify_mode|, then compare the encoded FEC with the one in
  // |path|, otherwise write the encoded FEC to |path|. We can't encode as we go
  // in each Update() like hash tree, because for every rs block, its data are
  // spreaded across entire |data_size|, unless we can cache all data in
  // memory, we have to re-read them from disk.
  static bool EncodeFEC(FileDescriptorPtr read_fd,
                        FileDescriptorPtr write_fd,
                        uint64_t data_offset,
                        uint64_t data_size,
                        uint64_t fec_offset,
                        uint64_t fec_size,
                        uint32_t fec_roots,
                        uint32_t block_size,
                        bool verify_mode);
  static bool EncodeFEC(const std::string& path,
                        uint64_t data_offset,
                        uint64_t data_size,
                        uint64_t fec_offset,
                        uint64_t fec_size,
                        uint32_t fec_roots,
                        uint32_t block_size,
                        bool verify_mode);

 private:
  const InstallPlan::Partition* partition_ = nullptr;

  std::unique_ptr<HashTreeBuilder> hash_tree_builder_;
  uint64_t total_offset_ = 0;
  DISALLOW_COPY_AND_ASSIGN(VerityWriterAndroid);
};

}  // namespace chromeos_update_engine

#endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_VERITY_WRITER_ANDROID_H_