update_engine: New BootControlInterface class.
The new BootControlInterface class is a platform-independent
abstraction to control the bootloader. It provides methods for setting
what partition slots are available for booting and getting the
bootloader status about the available slots.
The Chrome OS specific implementation of the bootloader was moved to
the BootControlChromeOS which now depends on the vboot_host
implementation used in Chrome OS. Follow up CL will implement the
equivalent class for Brillo.
BUG=b:23010637
TEST=unittests; cros flash from the new image and rolled back from it.
Change-Id: I0a03aeeb8c21d8c99e1866b625e6e8c96628215b
diff --git a/boot_control_chromeos.h b/boot_control_chromeos.h
new file mode 100644
index 0000000..a7c269e
--- /dev/null
+++ b/boot_control_chromeos.h
@@ -0,0 +1,82 @@
+//
+// 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_CHROMEOS_H_
+#define UPDATE_ENGINE_BOOT_CONTROL_CHROMEOS_H_
+
+#include <string>
+
+#include <gtest/gtest_prod.h> // for FRIEND_TEST
+
+#include "update_engine/boot_control_interface.h"
+
+namespace chromeos_update_engine {
+
+// The Chrome OS implementation of the BootControlInterface. This interface
+// assumes the partition names and numbers used in Chrome OS devices.
+class BootControlChromeOS : public BootControlInterface {
+ public:
+ BootControlChromeOS() = default;
+ ~BootControlChromeOS() = default;
+
+ // Initialize the BootControl instance loading the constant values. Returns
+ // whether the operation succeeded. In case of failure, normally meaning
+ // some critical failure such as we couldn't determine the slot that we
+ // booted from, the implementation will pretend that there's only one slot and
+ // therefore A/B updates are disabled.
+ bool Init();
+
+ // BootControlInterface overrides.
+ unsigned int GetNumSlots() const override;
+ BootControlInterface::Slot GetCurrentSlot() const override;
+ bool GetPartitionDevice(const std::string& partition_name,
+ BootControlInterface::Slot slot,
+ std::string* device) const override;
+ bool IsSlotBootable(BootControlInterface::Slot slot) const override;
+ bool MarkSlotUnbootable(BootControlInterface::Slot slot) override;
+
+ private:
+ friend class BootControlChromeOSTest;
+ FRIEND_TEST(BootControlChromeOSTest, SysfsBlockDeviceTest);
+ FRIEND_TEST(BootControlChromeOSTest, GetPartitionNumberTest);
+
+ // Returns the sysfs block device for a root block device. For example,
+ // SysfsBlockDevice("/dev/sda") returns "/sys/block/sda". Returns an empty
+ // string if the input device is not of the "/dev/xyz" form.
+ static std::string SysfsBlockDevice(const std::string& device);
+
+ // Returns true if the root |device| (e.g., "/dev/sdb") is known to be
+ // removable, false otherwise.
+ static bool IsRemovableDevice(const std::string& device);
+
+ // Return the hard-coded partition number used in Chrome OS for the passed
+ // |partition_name| and |slot|. In case of invalid data, returns -1.
+ int GetPartitionNumber(const std::string partition_name,
+ BootControlInterface::Slot slot) const;
+
+ // Cached values for GetNumSlots() and GetCurrentSlot().
+ BootControlInterface::Slot num_slots_{1};
+ BootControlInterface::Slot current_slot_{BootControlInterface::kInvalidSlot};
+
+ // The block device of the disk we booted from, without the partition number.
+ std::string boot_disk_name_;
+
+ DISALLOW_COPY_AND_ASSIGN(BootControlChromeOS);
+};
+
+} // namespace chromeos_update_engine
+
+#endif // UPDATE_ENGINE_BOOT_CONTROL_CHROMEOS_H_
