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 <map> 22 #include <string> 23 #include <vector> 24 25 #include <base/callback.h> 26 #include <base/macros.h> 27 28 #include "update_engine/common/dynamic_partition_control_interface.h" 29 #include "update_engine/update_metadata.pb.h" 30 31 namespace chromeos_update_engine { 32 33 // The abstract boot control interface defines the interaction with the 34 // platform's bootloader hiding vendor-specific details from the rest of 35 // update_engine. This interface is used for controlling where the device should 36 // boot from. 37 class BootControlInterface { 38 public: 39 using Slot = unsigned int; 40 41 static const Slot kInvalidSlot = UINT_MAX; 42 43 virtual ~BootControlInterface() = default; 44 45 // Return the number of update slots in the system. A system will normally 46 // have two slots, named "A" and "B" in the documentation, but sometimes 47 // images running from other media can have only one slot, like some USB 48 // image. Systems with only one slot won't be able to update. 49 virtual unsigned int GetNumSlots() const = 0; 50 51 // Return the slot where we are running the system from. On success, the 52 // result is a number between 0 and GetNumSlots() - 1. Otherwise, log an error 53 // and return kInvalidSlot. 54 virtual Slot GetCurrentSlot() const = 0; 55 56 // Determines the block device for the given partition name and slot number. 57 // The |slot| number must be between 0 and GetNumSlots() - 1 and the 58 // |partition_name| is a platform-specific name that identifies a partition on 59 // every slot. In order to access the dynamic partitions in the target slot, 60 // GetDynamicPartitionControl()->PreparePartitionsForUpdate() must be called 61 // (with |update| == true for the first time for a payload, and |false| for 62 // for the rest of the times) prior to calling this function. On success, 63 // returns true and stores the block device in |device|. 64 virtual bool GetPartitionDevice(const std::string& partition_name, 65 Slot slot, 66 std::string* device) const = 0; 67 68 // Returns whether the passed |slot| is marked as bootable. Returns false if 69 // the slot is invalid. 70 virtual bool IsSlotBootable(Slot slot) const = 0; 71 72 // Mark the specified slot unbootable. No other slot flags are modified. 73 // Returns true on success. 74 virtual bool MarkSlotUnbootable(Slot slot) = 0; 75 76 // Set the passed |slot| as the preferred boot slot. Returns whether it 77 // succeeded setting the active slot. If succeeded, on next boot the 78 // bootloader will attempt to load the |slot| marked as active. Note that this 79 // method doesn't change the value of GetCurrentSlot() on the current boot. 80 virtual bool SetActiveBootSlot(Slot slot) = 0; 81 82 // Mark the current slot as successfully booted asynchronously. No other slot 83 // flags are modified. Returns false if it was not able to schedule the 84 // operation, otherwise, returns true and calls the |callback| with the result 85 // of the operation. 86 virtual bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) = 0; 87 88 // Check if |slot| is marked boot successfully. 89 virtual bool IsSlotMarkedSuccessful(Slot slot) const = 0; 90 91 // Return the dynamic partition control interface. 92 virtual DynamicPartitionControlInterface* GetDynamicPartitionControl() = 0; 93 94 // Return a human-readable slot name used for logging. SlotName(Slot slot)95 static std::string SlotName(Slot slot) { 96 if (slot == kInvalidSlot) 97 return "INVALID"; 98 if (slot < 26) 99 return std::string(1, 'A' + slot); 100 return "TOO_BIG"; 101 } 102 103 protected: 104 BootControlInterface() = default; 105 106 private: 107 DISALLOW_COPY_AND_ASSIGN(BootControlInterface); 108 }; 109 110 } // namespace chromeos_update_engine 111 112 #endif // UPDATE_ENGINE_COMMON_BOOT_CONTROL_INTERFACE_H_ 113