typedef struct File File;typedef struct Fs Fs; #include "dosfs.h"#include "kfs.h" struct File{	union{		Dosfile	dos;		Kfsfile	kfs;		int walked;	};	Fs	*fs;	char	*path;}; struct Fs{	union {		Dos dos;		Kfs kfs;	};	int	dev;				/* device id */	long	(*diskread)(Fs*, void*, long);	/* disk read routine */	vlong	(*diskseek)(Fs*, vlong);	/* disk seek routine */	long	(*read)(File*, void*, long);	int	(*walk)(File*, char*);	File	root;}; extern int chatty;extern int dotini(Fs*);extern int fswalk(Fs*, char*, File*);extern int fsread(File*, void*, long);extern int fsboot(Fs*, char*, Boot*); #define BADPTR(x) ((ulong)x < 0x80000000)