zircon/system/ulib/paver/device-partitioner.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <stdbool.h>

#include <fbl/function.h>
#include <fbl/string.h>
#include <fbl/unique_fd.h>
#include <fbl/unique_ptr.h>
#include <fbl/vector.h>
#include <fuchsia/hardware/block/c/fidl.h>
#include <gpt/gpt.h>
#include <lib/fzl/fdio.h>
#include <lib/zx/channel.h>
#include <zircon/types.h>

#include <utility>

namespace paver {
using gpt::GptDevice;

enum class Partition {
    kUnknown,
    kBootloader,
    kKernelC,
    kEfi,
    kZirconA,
    kZirconB,
    kZirconR,
    kVbMetaA,
    kVbMetaB,
    kVbMetaR,
    kFuchsiaVolumeManager,
};

const char* PartitionName(Partition type);

// A special filter for test injection.
// API should return true if device passed in should be filtered out.
extern bool (*TestBlockFilter)(const fbl::unique_fd&);

// Abstract device partitioner definition.
// This class defines common APIs for interacting with a device partitioner.
class DevicePartitioner {
public:
    // Factory method which automatically returns the correct DevicePartitioner
    // implementation. Returns nullptr on failure.
    static fbl::unique_ptr<DevicePartitioner> Create();

    virtual ~DevicePartitioner() = default;

    // Whether to use skip block interface or block interface for non-FVM
    // partitions.
    virtual bool UseSkipBlockInterface() const = 0;

    // Returns a file descriptor to a partition of type |partition_type|, creating it.
    // Assumes that the partition does not already exist.
    virtual zx_status_t AddPartition(Partition partition_type, fbl::unique_fd* out_fd) = 0;

    // Returns a file descriptor to a partition of type |partition_type| if one exists.
    virtual zx_status_t FindPartition(Partition partition_type, fbl::unique_fd* out_fd) const = 0;

    // Finalizes the partition of type |partition_type| after it has been
    // written.
    virtual zx_status_t FinalizePartition(Partition partition_type) = 0;

    // Wipes Fuchsia Volume Manager partition.
    virtual zx_status_t WipeFvm() = 0;

    // Returns block size in bytes for specified device.
    virtual zx_status_t GetBlockSize(const fbl::unique_fd& device_fd,
                                     uint32_t* block_size) const = 0;
};

// Useful for when a GPT table is available (e.g. x86 devices). Provides common
// utility functions.
class GptDevicePartitioner {
public:
    using FilterCallback = fbl::Function<bool(const gpt_partition_t&)>;

    // Find and initialize a GPT based device.
    static zx_status_t InitializeGpt(fbl::unique_fd devfs_root,
                                     fbl::unique_ptr<GptDevicePartitioner>* gpt_out);

    // Returns block info for a specified block device.
    zx_status_t GetBlockInfo(fuchsia_hardware_block_BlockInfo* block_info) const {
        memcpy(block_info, &block_info_, sizeof(*block_info));
        return ZX_OK;
    }

    GptDevice* GetGpt() const { return gpt_.get(); }
    zx::unowned_channel Channel() { return zx::unowned_channel(caller_.borrow_channel()); }

    // Find the first spot that has at least |bytes_requested| of space.
    //
    // Returns the |start_out| block and |length_out| blocks, indicating
    // how much space was found, on success. This may be larger than
    // the number of bytes requested.
    zx_status_t FindFirstFit(size_t bytes_requested, size_t* start_out, size_t* length_out) const;

    // Creates a partition, adds an entry to the GPT, and returns a file descriptor to it.
    // Assumes that the partition does not already exist.
    zx_status_t AddPartition(const char* name, uint8_t* type, size_t minimum_size_bytes,
                             size_t optional_reserve_bytes, fbl::unique_fd* out_fd);

    // Returns a file descriptor to a partition which can be paved,
    // if one exists.
    zx_status_t FindPartition(FilterCallback filter, gpt_partition_t** out,
                              fbl::unique_fd* out_fd);
    zx_status_t FindPartition(FilterCallback filter, fbl::unique_fd* out_fd) const;

    // Wipes a specified partition from the GPT, and overwrites first 8KiB with
    // nonsense.
    zx_status_t WipeFvm();

private:
    // Find and return the topological path of the GPT which we will pave.
    static bool FindTargetGptPath(const fbl::unique_fd& devfs_root, fbl::String* out);

    GptDevicePartitioner(fbl::unique_fd devfs_root, fbl::unique_fd fd,
                         fbl::unique_ptr<GptDevice> gpt,
                         fuchsia_hardware_block_BlockInfo block_info)
        : devfs_root_(std::move(devfs_root)), caller_(std::move(fd)), gpt_(std::move(gpt)),
          block_info_(block_info) {}

    zx_status_t CreateGptPartition(const char* name, uint8_t* type, uint64_t offset,
                                   uint64_t blocks, uint8_t* out_guid);

    fbl::unique_fd devfs_root_;
    fzl::FdioCaller caller_;
    fbl::unique_ptr<GptDevice> gpt_;
    fuchsia_hardware_block_BlockInfo block_info_;
};

// DevicePartitioner implementation for EFI based devices.
class EfiDevicePartitioner : public DevicePartitioner {
public:
    static zx_status_t Initialize(fbl::unique_fd devfs_root,
                                  fbl::unique_ptr<DevicePartitioner>* partitioner);

    bool UseSkipBlockInterface() const override { return false; }

    zx_status_t AddPartition(Partition partition_type, fbl::unique_fd* out_fd) override;

    zx_status_t FindPartition(Partition partition_type, fbl::unique_fd* out_fd) const override;

    zx_status_t FinalizePartition(Partition unused) override { return ZX_OK; }

    zx_status_t WipeFvm() override;

    zx_status_t GetBlockSize(const fbl::unique_fd& device_fd, uint32_t* block_size) const override;

private:
    EfiDevicePartitioner(fbl::unique_ptr<GptDevicePartitioner> gpt)
        : gpt_(std::move(gpt)) {}

    fbl::unique_ptr<GptDevicePartitioner> gpt_;
};

// DevicePartitioner implementation for ChromeOS devices.
class CrosDevicePartitioner : public DevicePartitioner {
public:
    static zx_status_t Initialize(fbl::unique_fd devfs_root,
                                  fbl::unique_ptr<DevicePartitioner>* partitioner);

    bool UseSkipBlockInterface() const override { return false; }

    zx_status_t AddPartition(Partition partition_type, fbl::unique_fd* out_fd) override;

    zx_status_t FindPartition(Partition partition_type, fbl::unique_fd* out_fd) const override;

    zx_status_t FinalizePartition(Partition unused) override;

    zx_status_t WipeFvm() override;

    zx_status_t GetBlockSize(const fbl::unique_fd& device_fd, uint32_t* block_size) const override;

private:
    CrosDevicePartitioner(fbl::unique_ptr<GptDevicePartitioner> gpt)
        : gpt_(std::move(gpt)) {}

    fbl::unique_ptr<GptDevicePartitioner> gpt_;
};

// DevicePartitioner implementation for devices which have fixed partition maps (e.g. ARM
// devices). It will not attempt to write a partition map of any kind to the device.
// Assumes standardized partition layout structure (e.g. ZIRCON-A, ZIRCON-B,
// ZIRCON-R).
class FixedDevicePartitioner : public DevicePartitioner {
public:
    static zx_status_t Initialize(fbl::unique_fd devfs_root,
                                  fbl::unique_ptr<DevicePartitioner>* partitioner);

    bool UseSkipBlockInterface() const override { return false; }

    zx_status_t AddPartition(Partition partition_type, fbl::unique_fd* out_fd) override;

    zx_status_t FindPartition(Partition partition_type, fbl::unique_fd* out_fd) const override;

    zx_status_t FinalizePartition(Partition unused) override { return ZX_OK; }

    zx_status_t WipeFvm() override;

    zx_status_t GetBlockSize(const fbl::unique_fd& device_fd, uint32_t* block_size) const override;

private:
    FixedDevicePartitioner(fbl::unique_fd devfs_root)
        : devfs_root_(std::move(devfs_root)) {}

    fbl::unique_fd devfs_root_;
};

// DevicePartitioner implementation for devices which have fixed partition maps, but do not expose a
// block device interface. Instead they expose devices with skip-block IOCTL interfaces. Like the
// FixedDevicePartitioner, it will not attempt to write a partition map of any kind to the device.
// Assumes standardized partition layout structure (e.g. ZIRCON-A, ZIRCON-B,
// ZIRCON-R).
class SkipBlockDevicePartitioner : public DevicePartitioner {
public:
    static zx_status_t Initialize(fbl::unique_fd devfs_root,
                                  fbl::unique_ptr<DevicePartitioner>* partitioner);

    bool UseSkipBlockInterface() const override { return true; }

    zx_status_t AddPartition(Partition partition_type, fbl::unique_fd* out_fd) override;

    zx_status_t FindPartition(Partition partition_type, fbl::unique_fd* out_fd) const override;

    zx_status_t FinalizePartition(Partition unused) override { return ZX_OK; }

    zx_status_t WipeFvm() override;

    zx_status_t GetBlockSize(const fbl::unique_fd& device_fd, uint32_t* block_size) const override;

private:
    SkipBlockDevicePartitioner(fbl::unique_fd devfs_root, fbl::unique_fd block_devfs_root)
        : devfs_root_(std::move(devfs_root)), block_devfs_root_(std::move(block_devfs_root)) {}

    fbl::unique_fd devfs_root_;
    fbl::unique_fd block_devfs_root_;
};
} // namespace paver