Function alq_open_flags

freebsd/kern/kern_alq.c:430–480

 */

int
alq_open_flags(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
    int size, int flags)
{
	struct thread *td;
	struct nameidata nd;
	struct alq *alq;
	int oflags;
	int error;

	KASSERT((size > 0), ("%s: size <= 0", __func__));

	*alqp = NULL;
	td = curthread;

	NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, file, td);
	oflags = FWRITE | O_NOFOLLOW | O_CREAT;

	error = vn_open_cred(&nd, &oflags, cmode, 0, cred, NULL);
	if (error)
		return (error);

	NDFREE(&nd, NDF_ONLY_PNBUF);
	/* We just unlock so we hold a reference */
	VOP_UNLOCK(nd.ni_vp);

	alq = malloc(sizeof(*alq), M_ALD, M_WAITOK|M_ZERO);
	alq->aq_vp = nd.ni_vp;
	alq->aq_cred = crhold(cred);

	mtx_init(&alq->aq_mtx, "ALD Queue", NULL, MTX_SPIN|MTX_QUIET);

	alq->aq_buflen = size;
	alq->aq_entmax = 0;
	alq->aq_entlen = 0;

	alq->aq_freebytes = alq->aq_buflen;
	alq->aq_entbuf = malloc(alq->aq_buflen, M_ALD, M_WAITOK|M_ZERO);
	alq->aq_writehead = alq->aq_writetail = 0;
	if (flags & ALQ_ORDERED)
		alq->aq_flags |= AQ_ORDERED;

	if ((error = ald_add(alq)) != 0) {
		alq_destroy(alq);
		return (error);
	}

	*alqp = alq;

	return (0);
}

int
alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode,