Function proc_set_cred

freebsd/kern/kern_prot.c:2179–2197

* Change process credentials. * Callers are responsible for providing the reference for passed credentials * and for freeing old ones. * * Process has to be locked except when it does not have credentials (as it * should not be visible just yet) or when newcred is NULL (as this can be * only used when the process is about to be freed, at which point it should * not be visible anymore). */

 * not be visible anymore).
 */
void
proc_set_cred(struct proc *p, struct ucred *newcred)
{
	struct ucred *cr;

	cr = p->p_ucred;
	MPASS(cr != NULL);
	PROC_LOCK_ASSERT(p, MA_OWNED);
	KASSERT(newcred->cr_users == 0, ("%s: users %d not 0 on cred %p",
	    __func__, newcred->cr_users, newcred));
	mtx_lock(&cr->cr_mtx);
	KASSERT(cr->cr_users > 0, ("%s: users %d not > 0 on cred %p",
	    __func__, cr->cr_users, cr));
	cr->cr_users--;
	mtx_unlock(&cr->cr_mtx);
	p->p_ucred = newcred;
	newcred->cr_users = 1;
	PROC_UPDATE_COW(p);
}

void
proc_unset_cred(struct proc *p)