BootControlStub: New class used if CreateBootControl() fail.
This can happen if running update_engine on Brillo in the emulator or
other device lacking a boot_control HAL implementation. With this
change, the update_engine process continues to run but updates won't
work.
Bug: 25012817
Change-Id: I03d516c5e9a53c893c376885cd48068cd359e902
Test: update_engine no longer crashes on brilloemulator_arm.
diff --git a/boot_control_stub.h b/boot_control_stub.h
new file mode 100644
index 0000000..39fcb7a
--- /dev/null
+++ b/boot_control_stub.h
@@ -0,0 +1,55 @@
+//
+// 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_STUB_H_
+#define UPDATE_ENGINE_BOOT_CONTROL_STUB_H_
+
+#include <string>
+
+#include "update_engine/boot_control_interface.h"
+
+namespace chromeos_update_engine {
+
+// An implementation of the BootControlInterface that does nothing,
+// typically used when e.g. an underlying HAL implementation cannot be
+// loaded or doesn't exist.
+//
+// You are gauranteed that the implementation of GetNumSlots() method
+// always returns 0. This can be used to identify that this
+// implementation is in use.
+class BootControlStub : public BootControlInterface {
+ public:
+ BootControlStub() = default;
+ ~BootControlStub() = default;
+
+ // 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;
+ bool SetActiveBootSlot(BootControlInterface::Slot slot) override;
+ bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) override;
+
+ private:
+ DISALLOW_COPY_AND_ASSIGN(BootControlStub);
+};
+
+} // namespace chromeos_update_engine
+
+#endif // UPDATE_ENGINE_BOOT_CONTROL_STUB_H_