deref_kptr
deref_kptr(p, &cur_disk, sizeof(cur_disk));
deref_kptr(p, &cur_disk, sizeof(cur_disk));
deref_kptr(cur_disk.dk_name, buf, sizeof(buf));
#define deref_nl(v, p, s) deref_kptr((void *)namelist[(v)].n_value, (p), (s));
static void deref_kptr(void *, void *, size_t);