P_PPTRACE
p->p_flag &= ~(P_PPWAIT | P_PPTRACE);
if ((p->p_flag & (P_TRACED | P_PPWAIT | P_PPTRACE)) != 0) {
p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) {
(p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED &&
p->p_flag |= P_PPTRACE;