Function ptsdev_write

components/lwp/terminal/freebsd/tty_pts.c:163–240

}

static int ptsdev_write(struct lwp_tty *tp, struct uio *uio,
                        struct ucred *active_cred, int oflags,
                        struct rt_thread *td)
{
    struct pts_softc *psc = tty_softc(tp);
    char ib[256], *ibstart;
    size_t iblen, rintlen;
    int error = 0;

    if (uio->uio_resid == 0)
        return (0);

    for (;;)
    {
        ibstart = ib;
        iblen = MIN(uio->uio_resid, sizeof ib);
        error = uiomove(ib, iblen, uio);

        tty_lock(tp);
        if (error != 0)
        {
            iblen = 0;
            goto done;
        }

        /*
         * When possible, avoid the slow path. rint_bypass()
         * copies all input to the input queue at once.
         */
        MPASS(iblen > 0);
        do
        {
            rintlen = ttydisc_rint_simple(tp, ibstart, iblen);
            ibstart += rintlen;
            iblen -= rintlen;
            if (iblen == 0)
            {
                /* All data written. */
                break;
            }

            /* Maybe the device isn't used anyway. */
            if (psc->pts_flags & PTS_FINISHED)
            {
                error = -EIO;
                goto done;
            }

            /* Wait for more data. */
            if (oflags & O_NONBLOCK)
            {
                error = -EWOULDBLOCK;
                goto done;
            }

            /* Wake up users on the slave side. */
            ttydisc_rint_done(tp);
            error = cv_wait_sig(&psc->pts_inwait, tp->t_mtx);