Kernel: add NullDevice to /dev/null

kernel/include/kernel/Device/NullDevice.h

@@ -0,0 +1,27 @@
+#include <BAN/UniqPtr.h>
+#include <kernel/Device/Device.h>
+
+namespace Kernel
+{
+
+	class NullDevice : public CharacterDevice
+	{
+	public:
+		static BAN::ErrorOr<BAN::RefPtr<NullDevice>> create(mode_t, uid_t, gid_t);
+
+		virtual dev_t rdev() const override { return m_rdev; }
+
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override { return 0; }
+		virtual BAN::ErrorOr<size_t> write(size_t, const void*, size_t size) override { return size; };
+
+	protected:
+		NullDevice(mode_t mode, uid_t uid, gid_t gid, dev_t rdev)
+			: CharacterDevice(mode, uid, gid)
+			, m_rdev(rdev)
+		{ }
+	
+	private:
+		const dev_t m_rdev;
+	};
+
+}