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 namespace chromeos_update_engine { 29 30 // The abstract boot control interface defines the interaction with the 31 // platform's bootloader hiding vendor-specific details from the rest of 32 // update_engine. This interface is used for controlling where the device should 33 // boot from. 34 class BootControlInterface { 35 public: 36 using Slot = unsigned int; 37 38 struct PartitionMetadata { 39 struct Partition { 40 std::string name; 41 uint64_t size; 42 }; 43 struct Group { 44 std::string name; 45 uint64_t size; 46 std::vector<Partition> partitions; 47 }; 48 std::vector<Group> groups; 49 }; 50 51 static const Slot kInvalidSlot = UINT_MAX; 52 53 virtual ~BootControlInterface() = default; 54 55 // Return the number of update slots in the system. A system will normally 56 // have two slots, named "A" and "B" in the documentation, but sometimes 57 // images running from other media can have only one slot, like some USB 58 // image. Systems with only one slot won't be able to update. 59 virtual unsigned int GetNumSlots() const = 0; 60 61 // Return the slot where we are running the system from. On success, the 62 // result is a number between 0 and GetNumSlots() - 1. Otherwise, log an error 63 // and return kInvalidSlot. 64 virtual Slot GetCurrentSlot() const = 0; 65 66 // Determines the block device for the given partition name and slot number. 67 // The |slot| number must be between 0 and GetNumSlots() - 1 and the 68 // |partition_name| is a platform-specific name that identifies a partition on 69 // every slot. In order to access the dynamic partitions in the target slot, 70 // InitPartitionMetadata() must be called (once per payload) prior to calling 71 // this function. On success, returns true and stores the block device in 72 // |device|. 73 virtual bool GetPartitionDevice(const std::string& partition_name, 74 Slot slot, 75 std::string* device) const = 0; 76 77 // Returns whether the passed |slot| is marked as bootable. Returns false if 78 // the slot is invalid. 79 virtual bool IsSlotBootable(Slot slot) const = 0; 80 81 // Mark the specified slot unbootable. No other slot flags are modified. 82 // Returns true on success. 83 virtual bool MarkSlotUnbootable(Slot slot) = 0; 84 85 // Set the passed |slot| as the preferred boot slot. Returns whether it 86 // succeeded setting the active slot. If succeeded, on next boot the 87 // bootloader will attempt to load the |slot| marked as active. Note that this 88 // method doesn't change the value of GetCurrentSlot() on the current boot. 89 virtual bool SetActiveBootSlot(Slot slot) = 0; 90 91 // Mark the current slot as successfully booted asynchronously. No other slot 92 // flags are modified. Returns false if it was not able to schedule the 93 // operation, otherwise, returns true and calls the |callback| with the result 94 // of the operation. 95 virtual bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) = 0; 96 97 // Initializes the metadata of the underlying partitions for a given |slot| 98 // and sets up the states for accessing dynamic partitions. 99 // |partition_metadata| will be written to the specified |slot| if 100 // |update_metadata| is set. 101 virtual bool InitPartitionMetadata( 102 Slot slot, 103 const PartitionMetadata& partition_metadata, 104 bool update_metadata) = 0; 105 106 // Do necessary clean-up operations after the whole update. 107 virtual void Cleanup() = 0; 108 109 // Return a human-readable slot name used for logging. SlotName(Slot slot)110 static std::string SlotName(Slot slot) { 111 if (slot == kInvalidSlot) 112 return "INVALID"; 113 if (slot < 26) 114 return std::string(1, 'A' + slot); 115 return "TOO_BIG"; 116 } 117 118 protected: 119 BootControlInterface() = default; 120 121 private: 122 DISALLOW_COPY_AND_ASSIGN(BootControlInterface); 123 }; 124 125 } // namespace chromeos_update_engine 126 127 #endif // UPDATE_ENGINE_COMMON_BOOT_CONTROL_INTERFACE_H_ 128