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//
// Copyright (C) 2015 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_BOOT_CONTROL_INTERFACE_H_
#define UPDATE_ENGINE_BOOT_CONTROL_INTERFACE_H_
#include <climits>
#include <string>
#include <base/callback.h>
#include <base/macros.h>
namespace chromeos_update_engine {
// The abstract boot control interface defines the interaction with the
// platform's bootloader hiding vendor-specific details from the rest of
// update_engine. This interface is used for controlling where the device should
// boot from.
class BootControlInterface {
public:
using Slot = unsigned int;
static const Slot kInvalidSlot = UINT_MAX;
virtual ~BootControlInterface() = default;
// Return the number of update slots in the system. A system will normally
// have two slots, named "A" and "B" in the documentation, but sometimes
// images running from other media can have only one slot, like some USB
// image. Systems with only one slot won't be able to update.
virtual unsigned int GetNumSlots() const = 0;
// Return the slot where we are running the system from. On success, the
// result is a number between 0 and GetNumSlots() - 1. Otherwise, log an error
// and return kInvalidSlot.
virtual Slot GetCurrentSlot() const = 0;
// Determines the block device for the given partition name and slot number.
// The |slot| number must be between 0 and GetNumSlots() - 1 and the
// |partition_name| is a platform-specific name that identifies a partition on
// every slot. On success, returns true and stores the block device in
// |device|.
virtual bool GetPartitionDevice(const std::string& partition_name,
Slot slot,
std::string* device) const = 0;
// Returns whether the passed |slot| is marked as bootable. Returns false if
// the slot is invalid.
virtual bool IsSlotBootable(Slot slot) const = 0;
// Mark the specified slot unbootable. No other slot flags are modified.
// Returns true on success.
virtual bool MarkSlotUnbootable(Slot slot) = 0;
// Set the passed |slot| as the preferred boot slot. Returns whether it
// succeeded setting the active slot. If succeeded, on next boot the
// bootloader will attempt to load the |slot| marked as active. Note that this
// method doesn't change the value of GetCurrentSlot() on the current boot.
virtual bool SetActiveBootSlot(Slot slot) = 0;
// Mark the current slot as successfully booted asynchronously. No other slot
// flags are modified. Returns false if it was not able to schedule the
// operation, otherwise, returns true and calls the |callback| with the result
// of the operation.
virtual bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) = 0;
// Return a human-readable slot name used for logging.
static std::string SlotName(Slot slot) {
if (slot == kInvalidSlot)
return "INVALID";
if (slot < 26)
return std::string(1, 'A' + slot);
return "TOO_BIG";
}
protected:
BootControlInterface() = default;
private:
DISALLOW_COPY_AND_ASSIGN(BootControlInterface);
};
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_BOOT_CONTROL_INTERFACE_H_