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// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef LIBBRILLO_BRILLO_BLKDEV_UTILS_DEVICE_MAPPER_TASK_H_
#define LIBBRILLO_BRILLO_BLKDEV_UTILS_DEVICE_MAPPER_TASK_H_
#include <libdevmapper.h>
#include <memory>
#include <string>
#include <brillo/secure_blob.h>
namespace brillo {
using DmTaskPtr = std::unique_ptr<dm_task, void (*)(dm_task*)>;
// Abstract class to manage DM devices.
// This class implements the bare minimum set of functions
// required to create/remove DM devices. DevmapperTask is the equivalent
// of a command to the device mapper to set/get targets associated with a
// logical DM device, but omits, for now, finer-grained commands.
// A target represents a segment of a DM device.
//
// The abstract class is strictly based on the dm_task_* functions
// from libdevmapper, but the interface provides sufficient flexibility
// for other implementations (eg. invoking dmsetup) or testing facades.
//
// The task type enum is defined in libdevmapper.h: for simplicity, the same
// enum types are reused in fake implementations of DevmapperTask.
// The following task types have been tested with DeviceMapper functions:
// - DM_DEVICE_CREATE: used in DeviceMapper::Setup.
// - DM_DEVICE_REMOVE: used in DeviceMapper::Remove.
// - DM_DEVICE_TABLE: used in DeviceMapper::GetTable and
// DeviceMapper::WipeTable.
// - DM_DEVICE_RELOAD: used in DeviceMapper::WipeTable.
class DevmapperTask {
public:
virtual ~DevmapperTask() = default;
// Sets device name for the command.
virtual bool SetName(const std::string& name) = 0;
// Adds a target to the command. Should be followed by a Run();
// Parameters:
// start: start of target in device.
// sectors: number of sectors in the target.
// type: type of the target.
// parameters: target parameters.
virtual bool AddTarget(uint64_t start,
uint64_t sectors,
const std::string& type,
const SecureBlob& parameters) = 0;
// Gets the next target from the command.
// Returns true while another target exists.
// If no target exist for the device, GetNextTarget sets all
// parameters to 0 and returns false.
//
// Parameters:
// start: start of target in device.
// sectors: number of sectors in the target.
// type: type of the target.
// parameters: target parameters.
virtual bool GetNextTarget(uint64_t* start,
uint64_t* sectors,
std::string* type,
SecureBlob* parameters) = 0;
// Run the task.
// Returns true if the task succeeded.
//
// Parameters:
// udev_sync: Enable/Disable udev_synchronization. Defaults to false.
// Enable only for tasks that create/remove/rename files to
// prevent both udevd and libdevmapper from attempting to
// add or remove files.
virtual bool Run(bool udev_sync = false) = 0;
};
// Libdevmapper implementation for DevmapperTask.
class DevmapperTaskImpl : public DevmapperTask {
public:
explicit DevmapperTaskImpl(int type);
~DevmapperTaskImpl() override = default;
bool SetName(const std::string& name) override;
bool AddTarget(uint64_t start,
uint64_t sectors,
const std::string& target,
const SecureBlob& parameters) override;
bool GetNextTarget(uint64_t* start,
uint64_t* sectors,
std::string* target,
SecureBlob* parameters) override;
bool Run(bool udev_sync = true) override;
private:
DmTaskPtr task_;
void* next_target_ = nullptr;
};
} // namespace brillo
#endif // LIBBRILLO_BRILLO_BLKDEV_UTILS_DEVICE_MAPPER_TASK_H_