Move VFS sources into Kernel/.

Kernel/CharacterDevice.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <AK/Retainable.h>
+#include <AK/Types.h>
+#include "Limits.h"
+#include "FileDescriptor.h"
+
+class Process;
+
+class CharacterDevice : public Retainable<CharacterDevice> {
+public:
+    virtual ~CharacterDevice();
+
+    InodeMetadata metadata() const { return { }; }
+
+    virtual RetainPtr<FileDescriptor> open(int& error, int options);
+
+    virtual bool can_read(Process&) const = 0;
+    virtual bool can_write(Process&) const = 0;
+
+    virtual ssize_t read(Process&, byte* buffer, size_t bufferSize) = 0;
+    virtual ssize_t write(Process&, const byte* buffer, size_t bufferSize) = 0;
+
+    unsigned major() const { return m_major; }
+    unsigned minor() const { return m_minor; }
+
+    virtual bool is_tty() const { return false; }
+    virtual bool is_master_pty() const { return false; }
+
+    virtual int ioctl(Process&, unsigned request, unsigned arg);
+
+    virtual const char* class_name() const = 0;
+
+protected:
+    CharacterDevice(unsigned major, unsigned minor) : m_major(major), m_minor(minor) { }
+
+private:
+    unsigned m_major { 0 };
+    unsigned m_minor { 0 };
+};