typedef void (*callback_t)(struct sigcontext *);

void register_callback(u_long vec, callback_t func, char *name);
callback_t find_callback(u_long vec);
u_long insert_generic_trampoline(size_t len, u_char *p);
u_long insert_softint_trampoline(void);
u_long insert_hardint_trampoline(void);
u_long insert_null_trampoline(void);