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	 aee4786d8e
			
		
	
	
		aee4786d8e
		
	
	
	
	
		
			
			This singleton simplifies many aspects that we struggled with before: 1. There's no need to make derived classes of Device expose the constructor as public anymore. The singleton is a friend of them, so he can call the constructor. This solves the issue with try_create_device helper neatly, hopefully for good. 2. Getting a reference of the NullDevice is now being done from this singleton, which means that NullDevice no longer needs to use its own singleton, and we can apply the try_create_device helper on it too :) 3. We can now defer registration completely after the Device constructor which means the Device constructor is merely assigning the major and minor numbers of the Device, and the try_create_device helper ensures it calls the after_inserting method immediately after construction. This creates a great opportunity to make registration more OOM-safe.
		
			
				
	
	
		
			42 lines
		
	
	
	
		
			1.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			42 lines
		
	
	
	
		
			1.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2021, Patrick Meyer <git@the-space.agency>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #pragma once
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| 
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| #include <Kernel/Devices/BlockDevice.h>
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| #include <Kernel/Devices/KCOVInstance.h>
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| 
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| namespace Kernel {
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| class KCOVDevice final : public BlockDevice {
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|     AK_MAKE_ETERNAL
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|     friend class DeviceManagement;
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| 
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| public:
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|     static HashMap<ProcessID, KCOVInstance*>* proc_instance;
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|     static HashMap<ThreadID, KCOVInstance*>* thread_instance;
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| 
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|     static NonnullRefPtr<KCOVDevice> must_create();
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|     static void free_thread();
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|     static void free_process();
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| 
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|     // ^File
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|     KResultOr<Memory::Region*> mmap(Process&, OpenFileDescription&, Memory::VirtualRange const&, u64 offset, int prot, bool shared) override;
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|     KResultOr<NonnullRefPtr<OpenFileDescription>> open(int options) override;
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| 
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| protected:
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|     KCOVDevice();
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| 
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|     virtual StringView class_name() const override { return "KCOVDevice"; }
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| 
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|     virtual bool can_read(const OpenFileDescription&, size_t) const override final { return true; }
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|     virtual bool can_write(const OpenFileDescription&, size_t) const override final { return true; }
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|     virtual void start_request(AsyncBlockDeviceRequest& request) override final { request.complete(AsyncDeviceRequest::Failure); }
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|     virtual KResultOr<size_t> read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t) override { return EINVAL; }
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|     virtual KResultOr<size_t> write(OpenFileDescription&, u64, const UserOrKernelBuffer&, size_t) override { return EINVAL; }
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|     virtual KResult ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg) override;
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| };
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| 
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| }
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