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_BOOT_CONTROL_CHROMEOS_H_
18#define UPDATE_ENGINE_BOOT_CONTROL_CHROMEOS_H_
19
20#include <string>
21
22#include <base/callback.h>
23#include <gtest/gtest_prod.h>  // for FRIEND_TEST
24
25#include "update_engine/common/boot_control_interface.h"
26
27namespace chromeos_update_engine {
28
29// The Chrome OS implementation of the BootControlInterface. This interface
30// assumes the partition names and numbers used in Chrome OS devices.
31class BootControlChromeOS : public BootControlInterface {
32 public:
33  BootControlChromeOS() = default;
34  ~BootControlChromeOS() = default;
35
36  // Initialize the BootControl instance loading the constant values. Returns
37  // whether the operation succeeded. In case of failure, normally meaning
38  // some critical failure such as we couldn't determine the slot that we
39  // booted from, the implementation will pretend that there's only one slot and
40  // therefore A/B updates are disabled.
41  bool Init();
42
43  // BootControlInterface overrides.
44  unsigned int GetNumSlots() const override;
45  BootControlInterface::Slot GetCurrentSlot() const override;
46  bool GetPartitionDevice(const std::string& partition_name,
47                          BootControlInterface::Slot slot,
48                          std::string* device) const override;
49  bool IsSlotBootable(BootControlInterface::Slot slot) const override;
50  bool MarkSlotUnbootable(BootControlInterface::Slot slot) override;
51  bool SetActiveBootSlot(BootControlInterface::Slot slot) override;
52  bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) override;
53
54 private:
55  friend class BootControlChromeOSTest;
56  FRIEND_TEST(BootControlChromeOSTest, SysfsBlockDeviceTest);
57  FRIEND_TEST(BootControlChromeOSTest, GetPartitionNumberTest);
58
59  // Returns the sysfs block device for a root block device. For example,
60  // SysfsBlockDevice("/dev/sda") returns "/sys/block/sda". Returns an empty
61  // string if the input device is not of the "/dev/xyz" form.
62  static std::string SysfsBlockDevice(const std::string& device);
63
64  // Returns true if the root |device| (e.g., "/dev/sdb") is known to be
65  // removable, false otherwise.
66  static bool IsRemovableDevice(const std::string& device);
67
68  // Return the hard-coded partition number used in Chrome OS for the passed
69  // |partition_name| and |slot|. In case of invalid data, returns -1.
70  int GetPartitionNumber(const std::string partition_name,
71                         BootControlInterface::Slot slot) const;
72
73  // Cached values for GetNumSlots() and GetCurrentSlot().
74  BootControlInterface::Slot num_slots_{1};
75  BootControlInterface::Slot current_slot_{BootControlInterface::kInvalidSlot};
76
77  // The block device of the disk we booted from, without the partition number.
78  std::string boot_disk_name_;
79
80  DISALLOW_COPY_AND_ASSIGN(BootControlChromeOS);
81};
82
83}  // namespace chromeos_update_engine
84
85#endif  // UPDATE_ENGINE_BOOT_CONTROL_CHROMEOS_H_
86