Function pts_alloc_external

freebsd/kern/tty_pts.c:791–835

#ifdef PTS_EXTERNAL
int
pts_alloc_external(int fflags, struct thread *td, struct file *fp,
    struct cdev *dev, const char *name)
{
	int ok, error;
	struct tty *tp;
	struct pts_softc *psc;
	struct proc *p = td->td_proc;
	struct ucred *cred = td->td_ucred;

	/* Resource limiting. */
	PROC_LOCK(p);
	error = racct_add(p, RACCT_NPTS, 1);
	if (error != 0) {
		PROC_UNLOCK(p);
		return (EAGAIN);
	}
	ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
	if (!ok) {
		racct_sub(p, RACCT_NPTS, 1);
		PROC_UNLOCK(p);
		return (EAGAIN);
	}
	PROC_UNLOCK(p);

	/* Allocate TTY and softc. */
	psc = malloc(sizeof(struct pts_softc), M_PTS, M_WAITOK|M_ZERO);
	cv_init(&psc->pts_inwait, "ptsin");
	cv_init(&psc->pts_outwait, "ptsout");

	psc->pts_unit = -1;
	psc->pts_cdev = dev;
	psc->pts_cred = crhold(cred);

	tp = tty_alloc(&pts_class, psc);
	knlist_init_mtx(&psc->pts_inpoll.si_note, tp->t_mtx);
	knlist_init_mtx(&psc->pts_outpoll.si_note, tp->t_mtx);

	/* Expose the slave device as well. */
	tty_makedev(tp, td->td_ucred, "%s", name);

	finit(fp, fflags, DTYPE_PTS, tp, &ptsdev_ops);

	return (0);
}
#endif /* PTS_EXTERNAL */

int