proc_uidmatch
if (proc_uidmatch(cred, p->p_cred) == 0)
(proc_uidmatch(cred, p->p_cred) != 0))
if (so->so_cred && proc_uidmatch(cred, so->so_cred) == 0)
int proc_uidmatch(kauth_cred_t, kauth_cred_t);