partition_installer.h

/*
 * Copyright (C) 2019 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 <stdint.h>
#include <sys/mman.h>

#include <memory>
#include <string>

#include <android-base/unique_fd.h>
#include <android/gsi/IGsiService.h>
#include <android/gsi/MappedImage.h>
#include <libfiemap/image_manager.h>
#include <liblp/builder.h>

namespace android {
namespace gsi {

class GsiService;

class PartitionInstaller final {
    using ImageManager = android::fiemap::ImageManager;
    using MappedDevice = android::fiemap::MappedDevice;

  public:
    // Constructor for a new GSI installation.
    PartitionInstaller(GsiService* service, const std::string& installDir, const std::string& name,
                       const std::string& active_dsu, int64_t size, bool read_only);
    ~PartitionInstaller();

    // Methods for a clean GSI install.
    int StartInstall();
    bool CommitGsiChunk(int stream_fd, int64_t bytes);
    bool CommitGsiChunk(const void* data, size_t bytes);
    bool MapAshmem(int fd, size_t size);
    bool CommitGsiChunk(size_t bytes);
    int GetPartitionFd();

    static int WipeWritable(const std::string& active_dsu, const std::string& install_dir,
                            const std::string& name);

    // Returns the minimum free space to reserve for /data.
    static std::optional<uint64_t> GetMinimumFreeSpaceThreshold(const std::string& install_dir);

    // Finish a partition installation and release resources.
    // If the installation is incomplete or corrupted, the backing image would
    // be cleaned up and an error code is returned.
    // No method other than FinishInstall() and ~PartitionInstaller() should be
    // called after calling this method.
    // This method is also called by the destructor to free up resources.
    int FinishInstall();

    const std::string& install_dir() const { return install_dir_; }

  private:
    int PerformSanityChecks();
    int Preallocate();
    bool Format();
    bool CreateImage(const std::string& name, uint64_t size);
    std::unique_ptr<MappedDevice> OpenPartition(const std::string& name);
    int CheckInstallState();
    static const std::string GetBackingFile(std::string name);
    bool IsFinishedWriting();
    bool IsAshmemMapped();
    void UnmapAshmem();

    GsiService* service_;

    std::string install_dir_;
    std::string name_;
    std::string active_dsu_;
    std::unique_ptr<ImageManager> images_;
    uint64_t size_ = 0;
    bool readOnly_;
    // Remaining data we're waiting to receive for the GSI image.
    uint64_t gsi_bytes_written_ = 0;
    uint64_t ashmem_size_ = -1;
    void* ashmem_data_ = MAP_FAILED;

    bool finished_ = false;
    int finished_status_ = 0;

    std::unique_ptr<MappedDevice> system_device_;
};

}  // namespace gsi
}  // namespace android