4.1cBSD/a/sys/sys/tty_pty.c

/*	tty_pty.c	4.29	82/12/05	*/

/*
 * Pseudo-teletype Driver
 * (Actually two drivers, requiring two entries in 'cdevsw')
 */
#include "pty.h"

#if NPTY > 0
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/ioctl.h"
#include "../h/tty.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/conf.h"
#include "../h/file.h"
#include "../h/proc.h"
#include "../h/uio.h"
#include "../h/kernel.h"

#if NPTY == 1
#undef	NPTY
#define	NPTY	32		/* crude XXX */
#endif

#define BUFSIZ 100		/* Chunk size iomoved from user */

/*
 * pts == /dev/tty[pP]?
 * ptc == /dev/ptp[pP]?
 */
struct	tty pt_tty[NPTY];
struct	pt_ioctl {
	int	pt_flags;
	int	pt_gensym;
	struct	proc *pt_selr, *pt_selw;
	int	pt_send;
} pt_ioctl[NPTY];

#define	PF_RCOLL	0x01
#define	PF_WCOLL	0x02
#define	PF_NBIO		0x04
#define	PF_PKT		0x08		/* packet mode */
#define	PF_STOPPED	0x10		/* user told stopped */
#define	PF_REMOTE	0x20		/* remote and flow controlled input */
#define	PF_NOSTOP	0x40

/*ARGSUSED*/
ptsopen(dev, flag)
	dev_t dev;
{
	register struct tty *tp;

	if (minor(dev) >= NPTY)
		return (ENXIO);
	tp = &pt_tty[minor(dev)];
	if ((tp->t_state & TS_ISOPEN) == 0) {
		ttychars(tp);		/* Set up default chars */
		tp->t_flags = 0;	/* No features (nor raw mode) */
	} else if (tp->t_state&TS_XCLUDE && u.u_uid != 0)
		return (EBUSY);
	if (tp->t_oproc)			/* Ctrlr still around. */
		tp->t_state |= TS_CARR_ON;
	while ((tp->t_state & TS_CARR_ON) == 0) {
		tp->t_state |= TS_WOPEN;
		sleep((caddr_t)&tp->t_rawq, TTIPRI);
	}
	return ((*linesw[tp->t_line].l_open)(dev, tp));
}

ptsclose(dev)
	dev_t dev;
{
	register struct tty *tp;

	tp = &pt_tty[minor(dev)];
	(*linesw[tp->t_line].l_close)(tp);
	ttyclose(tp);
}

ptsread(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	register struct tty *tp = &pt_tty[minor(dev)];
	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
	int error = 0;

again:
	if (pti->pt_flags & PF_REMOTE) {
		while (tp == u.u_ttyp && u.u_procp->p_pgrp != tp->t_pgrp) {
			if (u.u_signal[SIGTTIN] == SIG_IGN ||
			    u.u_signal[SIGTTIN] == SIG_HOLD ||
	/*
			    (u.u_procp->p_flag&SDETACH) ||
	*/
			    u.u_procp->p_flag&SVFORK)
				return (EIO);
			gsignal(u.u_procp->p_pgrp, SIGTTIN);
			sleep((caddr_t)&lbolt, TTIPRI);
		}
		if (tp->t_rawq.c_cc == 0) {
			if (tp->t_state & TS_NBIO)
				return (EWOULDBLOCK);
			sleep((caddr_t)&tp->t_rawq, TTIPRI);
			goto again;
		}
		while (tp->t_rawq.c_cc > 1 && uio->uio_resid > 0)
			if (ureadc(getc(&tp->t_rawq), uio) < 0) {
				error = EFAULT;
				break;
			}
		if (tp->t_rawq.c_cc == 1)
			(void) getc(&tp->t_rawq);
		if (tp->t_rawq.c_cc)
			return (error);
	} else
		if (tp->t_oproc)
			error = (*linesw[tp->t_line].l_read)(tp, uio);
	wakeup((caddr_t)&tp->t_rawq.c_cf);
	if (pti->pt_selw) {
		selwakeup(pti->pt_selw, pti->pt_flags & PF_WCOLL);
		pti->pt_selw = 0;
		pti->pt_flags &= ~PF_WCOLL;
	}
	return (error);
}

/*
 * Write to pseudo-tty.
 * Wakeups of controlling tty will happen
 * indirectly, when tty driver calls ptsstart.
 */
ptswrite(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	register struct tty *tp;

	tp = &pt_tty[minor(dev)];
	if (tp->t_oproc == 0)
		return (EIO);
	return ((*linesw[tp->t_line].l_write)(tp, uio));
}

/*
 * Start output on pseudo-tty.
 * Wake up process selecting or sleeping for input from controlling tty.
 */
ptsstart(tp)
	struct tty *tp;
{
	register struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];

	if (tp->t_state & TS_TTSTOP)
		return;
	if (pti->pt_flags & PF_STOPPED) {
		pti->pt_flags &= ~PF_STOPPED;
		pti->pt_send = TIOCPKT_START;
	}
	ptcwakeup(tp);
}

ptcwakeup(tp)
	struct tty *tp;
{
	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];

	if (pti->pt_selr) {
		selwakeup(pti->pt_selr, pti->pt_flags & PF_RCOLL);
		pti->pt_selr = 0;
		pti->pt_flags &= ~PF_RCOLL;
	}
	wakeup((caddr_t)&tp->t_outq.c_cf);
}

/*ARGSUSED*/
ptcopen(dev, flag)
	dev_t dev;
	int flag;
{
	register struct tty *tp;
	struct pt_ioctl *pti;

	if (minor(dev) >= NPTY)
		return (ENXIO);
	tp = &pt_tty[minor(dev)];
	if (tp->t_oproc)
		return (EIO);
	tp->t_oproc = ptsstart;
	if (tp->t_state & TS_WOPEN)
		wakeup((caddr_t)&tp->t_rawq);
	tp->t_state |= TS_CARR_ON;
	pti = &pt_ioctl[minor(dev)];
	pti->pt_flags = 0;
	pti->pt_send = 0;
	return (0);
}

ptcclose(dev)
	dev_t dev;
{
	register struct tty *tp;

	tp = &pt_tty[minor(dev)];
	if (tp->t_state & TS_ISOPEN)
		gsignal(tp->t_pgrp, SIGHUP);
	tp->t_state &= ~TS_CARR_ON;	/* virtual carrier gone */
	flushtty(tp, FREAD|FWRITE);
	tp->t_oproc = 0;		/* mark closed */
}

ptcread(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	register struct tty *tp = &pt_tty[minor(dev)];
	struct pt_ioctl *pti;
	int error = 0;

	if ((tp->t_state&(TS_CARR_ON|TS_ISOPEN)) == 0)
		return (EIO);
	pti = &pt_ioctl[minor(dev)];
	if (pti->pt_flags & PF_PKT) {
		if (pti->pt_send) {
			error = ureadc(pti->pt_send, uio);
			if (error)
				return (error);
			pti->pt_send = 0;
			return (0);
		}
		error = ureadc(0, uio);
	}
	while (tp->t_outq.c_cc == 0 || (tp->t_state&TS_TTSTOP)) {
		if (pti->pt_flags&PF_NBIO)
			return (EWOULDBLOCK);
		sleep((caddr_t)&tp->t_outq.c_cf, TTIPRI);
	}
	while (tp->t_outq.c_cc && uio->uio_resid > 0)
		if (ureadc(getc(&tp->t_outq), uio) < 0) {
			error = EFAULT;
			break;
		}
	if (tp->t_outq.c_cc <= TTLOWAT(tp)) {
		if (tp->t_state&TS_ASLEEP) {
			tp->t_state &= ~TS_ASLEEP;
			wakeup((caddr_t)&tp->t_outq);
		}
		if (tp->t_wsel) {
			selwakeup(tp->t_wsel, tp->t_state & TS_WCOLL);
			tp->t_wsel = 0;
			tp->t_state &= ~TS_WCOLL;
		}
	}
	return (error);
}

ptsstop(tp, flush)
	register struct tty *tp;
	int flush;
{
	struct pt_ioctl *pti = &pt_ioctl[minor(tp->t_dev)];

	/* note: FLUSHREAD and FLUSHWRITE already ok */
	if (flush == 0) {
		flush = TIOCPKT_STOP;
		pti->pt_flags |= PF_STOPPED;
	} else {
		pti->pt_flags &= ~PF_STOPPED;
	}
	pti->pt_send |= flush;
	ptcwakeup(tp);
}

ptcselect(dev, rw)
	dev_t dev;
	int rw;
{
	register struct tty *tp = &pt_tty[minor(dev)];
	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
	struct proc *p;
	int s;

	if ((tp->t_state&(TS_CARR_ON|TS_ISOPEN)) == 0)
		return (1);
	s = spl5();
	switch (rw) {

	case FREAD:
		if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0) {
			splx(s);
			return (1);
		}
		if ((p = pti->pt_selr) && p->p_wchan == (caddr_t)&selwait)
			pti->pt_flags |= PF_RCOLL;
		else
			pti->pt_selr = u.u_procp;
		break;

	case FWRITE:
		if ((pti->pt_flags & PF_REMOTE) == 0 || tp->t_rawq.c_cc == 0) {
			splx(s);
			return (1);
		}
		if ((p = pti->pt_selw) && p->p_wchan == (caddr_t)&selwait)
			pti->pt_flags |= PF_WCOLL;
		else
			pti->pt_selw = u.u_procp;
		break;
	}
	splx(s);
	return (0);
}

ptcwrite(dev, uio)
	dev_t dev;
	struct uio *uio;
{
	register struct tty *tp = &pt_tty[minor(dev)];
	register char *cp, *ce;
	register int cc;
	char locbuf[BUFSIZ];
	int cnt = 0;
	struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
	int error = 0;

	if ((tp->t_state&(TS_CARR_ON|TS_ISOPEN)) == 0)
		return (EIO);
	do {
		register struct iovec *iov;

		if (uio->uio_iovcnt == 0)
			break;
		iov = uio->uio_iov;
		if (iov->iov_len == 0) {
			uio->uio_iovcnt--;	
			uio->uio_iov++;
			if (uio->uio_iovcnt < 0)
				panic("ptcwrite");
			continue;
		}
		cc = MIN(iov->iov_len, BUFSIZ);
		cp = locbuf;
		error = uiomove(cp, cc, UIO_WRITE, uio);
		if (error)
			break;
		ce = cp + cc;
again:
		if (pti->pt_flags & PF_REMOTE) {
			if (tp->t_rawq.c_cc) {
				if (pti->pt_flags & PF_NBIO) {
					iov->iov_base -= ce - cp;
					iov->iov_len += ce - cp;
					uio->uio_resid += ce - cp;
					uio->uio_offset -= ce - cp;
					return (EWOULDBLOCK);
				}
				sleep((caddr_t)&tp->t_rawq.c_cf, TTOPRI);
				goto again;
			}
			(void) b_to_q(cp, cc, &tp->t_rawq);
			(void) putc(0, &tp->t_rawq);
			wakeup((caddr_t)&tp->t_rawq);
			return (0);
		}
		while (cp < ce) {
			while (tp->t_delct && tp->t_rawq.c_cc >= TTYHOG - 2) {
				wakeup((caddr_t)&tp->t_rawq);
				if (tp->t_state & TS_NBIO) {
					iov->iov_base -= ce - cp;
					iov->iov_len += ce - cp;
					uio->uio_resid += ce - cp;
					uio->uio_offset -= ce - cp;
					if (cnt == 0)
						return (EWOULDBLOCK);
					return (0);
				}
				/* Better than just flushing it! */
				/* Wait for something to be read */
				sleep((caddr_t)&tp->t_rawq.c_cf, TTOPRI);
				goto again;
			}
			(*linesw[tp->t_line].l_rint)(*cp++, tp);
			cnt++;
		}
	} while (uio->uio_resid);
	return (error);
}

/*ARGSUSED*/
ptyioctl(dev, cmd, data, flag)
	caddr_t data;
	dev_t dev;
{
	register struct tty *tp = &pt_tty[minor(dev)];
	register struct pt_ioctl *pti = &pt_ioctl[minor(dev)];
	int error;

	/* IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG ??? */
	if (cdevsw[major(dev)].d_open == ptcopen)
		switch (cmd) {

		case TIOCPKT:
			if (*(int *)data)
				pti->pt_flags |= PF_PKT;
			else
				pti->pt_flags &= ~PF_PKT;
			return (0);

		case TIOCREMOTE:
			if (*(int *)data)
				pti->pt_flags |= PF_REMOTE;
			else
				pti->pt_flags &= ~PF_REMOTE;
			flushtty(tp, FREAD|FWRITE);
			return (0);

		case FIONBIO:
			if (*(int *)data)
				pti->pt_flags |= PF_NBIO;
			else
				pti->pt_flags &= ~PF_NBIO;
			return (0);

		case TIOCSETP:
			while (getc(&tp->t_outq) >= 0)
				;
			break;
		}
	error = ttioctl(tp, cmd, data, dev);
	if (error < 0)
		error = ENOTTY;
	{ int stop = (tp->t_stopc == ('s'&037) &&
		      tp->t_startc == ('q'&037));
	if (pti->pt_flags & PF_NOSTOP) {
		if (stop) {
			pti->pt_send &= TIOCPKT_NOSTOP;
			pti->pt_send |= TIOCPKT_DOSTOP;
			pti->pt_flags &= ~PF_NOSTOP;
			ptcwakeup(tp);
		}
	} else {
		if (stop == 0) {
			pti->pt_send &= ~TIOCPKT_DOSTOP;
			pti->pt_send |= TIOCPKT_NOSTOP;
			pti->pt_flags |= PF_NOSTOP;
			ptcwakeup(tp);
		}
	}
	}
	return (error);
}
#endif