1 // 2 // Copyright (C) 2015 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef UPDATE_ENGINE_COMMON_BOOT_CONTROL_INTERFACE_H_ 18 #define UPDATE_ENGINE_COMMON_BOOT_CONTROL_INTERFACE_H_ 19 20 #include <climits> 21 #include <string> 22 23 #include <base/callback.h> 24 #include <base/macros.h> 25 26 namespace chromeos_update_engine { 27 28 // The abstract boot control interface defines the interaction with the 29 // platform's bootloader hiding vendor-specific details from the rest of 30 // update_engine. This interface is used for controlling where the device should 31 // boot from. 32 class BootControlInterface { 33 public: 34 using Slot = unsigned int; 35 36 static const Slot kInvalidSlot = UINT_MAX; 37 38 virtual ~BootControlInterface() = default; 39 40 // Return the number of update slots in the system. A system will normally 41 // have two slots, named "A" and "B" in the documentation, but sometimes 42 // images running from other media can have only one slot, like some USB 43 // image. Systems with only one slot won't be able to update. 44 virtual unsigned int GetNumSlots() const = 0; 45 46 // Return the slot where we are running the system from. On success, the 47 // result is a number between 0 and GetNumSlots() - 1. Otherwise, log an error 48 // and return kInvalidSlot. 49 virtual Slot GetCurrentSlot() const = 0; 50 51 // Determines the block device for the given partition name and slot number. 52 // The |slot| number must be between 0 and GetNumSlots() - 1 and the 53 // |partition_name| is a platform-specific name that identifies a partition on 54 // every slot. On success, returns true and stores the block device in 55 // |device|. 56 virtual bool GetPartitionDevice(const std::string& partition_name, 57 Slot slot, 58 std::string* device) const = 0; 59 60 // Returns whether the passed |slot| is marked as bootable. Returns false if 61 // the slot is invalid. 62 virtual bool IsSlotBootable(Slot slot) const = 0; 63 64 // Mark the specified slot unbootable. No other slot flags are modified. 65 // Returns true on success. 66 virtual bool MarkSlotUnbootable(Slot slot) = 0; 67 68 // Set the passed |slot| as the preferred boot slot. Returns whether it 69 // succeeded setting the active slot. If succeeded, on next boot the 70 // bootloader will attempt to load the |slot| marked as active. Note that this 71 // method doesn't change the value of GetCurrentSlot() on the current boot. 72 virtual bool SetActiveBootSlot(Slot slot) = 0; 73 74 // Mark the current slot as successfully booted asynchronously. No other slot 75 // flags are modified. Returns false if it was not able to schedule the 76 // operation, otherwise, returns true and calls the |callback| with the result 77 // of the operation. 78 virtual bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) = 0; 79 80 // Return a human-readable slot name used for logging. 81 static std::string SlotName(Slot slot) { 82 if (slot == kInvalidSlot) 83 return "INVALID"; 84 if (slot < 26) 85 return std::string(1, 'A' + slot); 86 return "TOO_BIG"; 87 } 88 89 protected: 90 BootControlInterface() = default; 91 92 private: 93 DISALLOW_COPY_AND_ASSIGN(BootControlInterface); 94 }; 95 96 } // namespace chromeos_update_engine 97 98 #endif // UPDATE_ENGINE_COMMON_BOOT_CONTROL_INTERFACE_H_ 99
