RFPGLOCK
error = fork1(lp, RFFDG | RFPROC | RFPGLOCK, &p2);
error = fork1(lp, RFFDG | RFPROC | RFPPWAIT | RFMEM | RFPGLOCK, &p2);
error = fork1(lp, uap->flags | RFPGLOCK, &p2);
if ((flags & RFPGLOCK) && (plkgrp = p1->p_pgrp) != NULL) {
if (flags == (RFFDG | RFPROC | RFPGLOCK)) {
} else if (flags == (RFFDG | RFPROC | RFPPWAIT | RFMEM | RFPGLOCK)) {
#define RFKERNELONLY (RFPGLOCK | RFPPWAIT)