pty.c

minix3.1.1源代码

pty_t *pp;
{
/* Transfer bytes written to the output buffer to the PTY reader. */
  int count;

  /* While there are things to do. */
  for (;;) {
  	int s;
	count = bufend(pp->obuf) - pp->otail;
	if (count > pp->ocount) count = pp->ocount;
	if (count > pp->rdleft) count = pp->rdleft;
	if (count == 0) break;

	/* Copy from the output buffer to the readers address space. */
	if ((s = sys_vircopy(SELF, D, (vir_bytes)pp->otail,
		(vir_bytes) pp->rdproc, D, (vir_bytes) pp->rdvir, (phys_bytes) count)) != OK) {
		printf("pty tty%d: copy failed (error %d)\n",  s);
		break;
	}

	/* Bookkeeping. */
	pp->ocount -= count;
	if ((pp->otail += count) == bufend(pp->obuf)) pp->otail = pp->obuf;
	pp->rdvir += count;
	pp->rdcum += count;
	pp->rdleft -= count;
  }
}

/*===========================================================================*
 *				pty_finish				     *
 *===========================================================================*/
PRIVATE void pty_finish(pp)
pty_t *pp;
{
/* Finish the read request of a PTY reader if there is at least one byte
 * transferred.
 */
  if (pp->rdcum > 0) {
        if (pp->rdsendreply) {
		tty_reply(TASK_REPLY, pp->rdcaller, pp->rdproc, pp->rdcum);
		pp->rdleft = pp->rdcum = 0;
	}
	else
		notify(pp->rdcaller);
  }

}

/*===========================================================================*
 *				pty_read				     *
 *===========================================================================*/
PRIVATE int pty_read(tp, try)
tty_t *tp;
int try;
{
/* Offer bytes from the PTY writer for input on the TTY.  (Do it one byte at
 * a time, 99% of the writes will be for one byte, so no sense in being smart.)
 */
  pty_t *pp = tp->tty_priv;
  char c;

  if (pp->state & PTY_CLOSED) {
	if (try) return 1;
	if (tp->tty_inleft > 0) {
		tty_reply(tp->tty_inrepcode, tp->tty_incaller, tp->tty_inproc,
								tp->tty_incum);
		tp->tty_inleft = tp->tty_incum = 0;
	}
	return 1;
  }

  if (try) {
  	if (pp->wrleft > 0)
  		return 1;
  	return 0;
  }

  while (pp->wrleft > 0) {
  	int s;

	/* Transfer one character to 'c'. */
	if ((s = sys_vircopy(pp->wrproc, D, (vir_bytes) pp->wrvir,
		SELF, D, (vir_bytes) &c, (phys_bytes) 1)) != OK) {
		printf("pty: copy failed (error %d)\n", s);
		break;
	}

	/* Input processing. */
	if (in_process(tp, &c, 1) == 0) break;

	/* PTY writer bookkeeping. */
	pp->wrvir++;
	pp->wrcum++;
	if (--pp->wrleft == 0) {
		if (pp->wrsendreply) {
			tty_reply(TASK_REPLY, pp->wrcaller, pp->wrproc,
				pp->wrcum);
			pp->wrcum = 0;
		}
		else
			notify(pp->wrcaller);
	}
  }
}

/*===========================================================================*
 *				pty_close				     *
 *===========================================================================*/
PRIVATE int pty_close(tp, try)
tty_t *tp;
int try;
{
/* The tty side has closed, so shut down the pty side. */
  pty_t *pp = tp->tty_priv;

  if (!(pp->state & PTY_ACTIVE)) return;

  if (pp->rdleft > 0) {
  	assert(!pp->rdsendreply);
  	notify(pp->rdcaller);
  }

  if (pp->wrleft > 0) {
  	assert(!pp->wrsendreply);
  	notify(pp->wrcaller);
  }

  if (pp->state & PTY_CLOSED) pp->state = 0; else pp->state |= TTY_CLOSED;
}

/*===========================================================================*
 *				pty_icancel				     *
 *===========================================================================*/
PRIVATE int pty_icancel(tp, try)
tty_t *tp;
int try;
{
/* Discard waiting input. */
  pty_t *pp = tp->tty_priv;

  if (pp->wrleft > 0) {
  	assert(!pp->wrsendreply);
  	pp->wrcum += pp->wrleft;
  	pp->wrleft= 0;
  	notify(pp->wrcaller);
  }
}

/*===========================================================================*
 *				pty_ocancel				     *
 *===========================================================================*/
PRIVATE int pty_ocancel(tp, try)
tty_t *tp;
int try;
{
/* Drain the output buffer. */
  pty_t *pp = tp->tty_priv;

  pp->ocount = 0;
  pp->otail = pp->ohead;
}

/*===========================================================================*
 *				pty_init				     *
 *===========================================================================*/
PUBLIC void pty_init(tp)
tty_t *tp;
{
  pty_t *pp;
  int line;

  /* Associate PTY and TTY structures. */
  line = tp - &tty_table[NR_CONS + NR_RS_LINES];
  pp = tp->tty_priv = &pty_table[line];
  pp->tty = tp;
  pp->select_ops = 0;

  /* Set up output queue. */
  pp->ohead = pp->otail = pp->obuf;

  /* Fill in TTY function hooks. */
  tp->tty_devread = pty_read;
  tp->tty_devwrite = pty_write;
  tp->tty_echo = pty_echo;
  tp->tty_icancel = pty_icancel;
  tp->tty_ocancel = pty_ocancel;
  tp->tty_close = pty_close;
  tp->tty_select_ops = 0;
}

/*===========================================================================*
 *				pty_status				     *
 *===========================================================================*/
PUBLIC int pty_status(message *m_ptr)
{
	int i, event_found;
	pty_t *pp;

	event_found = 0;
	for (i= 0, pp = pty_table; i<NR_PTYS; i++, pp++) {
		if ((((pp->state & TTY_CLOSED) && pp->rdleft > 0) ||
			pp->rdcum > 0) &&
			pp->rdcaller == m_ptr->m_source)
		{
			m_ptr->m_type = DEV_REVIVE;
			m_ptr->REP_PROC_NR = pp->rdproc;
			m_ptr->REP_STATUS = pp->rdcum;

			pp->rdleft = pp->rdcum = 0;
			event_found = 1;
			break;
		}

		if ((((pp->state & TTY_CLOSED) && pp->wrleft > 0) ||
			pp->wrcum > 0) &&
			pp->wrcaller == m_ptr->m_source)
		{
			m_ptr->m_type = DEV_REVIVE;
			m_ptr->REP_PROC_NR = pp->wrproc;
			if (pp->wrcum == 0)
				m_ptr->REP_STATUS = EIO;
			else
				m_ptr->REP_STATUS = pp->wrcum;

			pp->wrleft = pp->wrcum = 0;
			event_found = 1;
			break;
		}

		if (pp->select_ready_ops && pp->select_proc == m_ptr->m_source) {
			m_ptr->m_type = DEV_IO_READY;
			m_ptr->DEV_MINOR = PTYPX_MINOR + i;
			m_ptr->DEV_SEL_OPS = pp->select_ready_ops;
			pp->select_ready_ops = 0;
			event_found = 1;
			break;
		}
	}
	return event_found;
}

/*===========================================================================*
 *				select_try_pty				     *
 *===========================================================================*/
PRIVATE int select_try_pty(tty_t *tp, int ops)
{
  	pty_t *pp = tp->tty_priv;
	int r = 0;

	if (ops & SEL_WR)  {
		/* Write won't block on error. */
		if (pp->state & TTY_CLOSED) r |= SEL_WR;
		else if (pp->wrleft != 0 || pp->wrcum != 0) r |= SEL_WR;
		else r |= SEL_WR;
	}

	if (ops & SEL_RD) {
		/* Read won't block on error. */
		if (pp->state & TTY_CLOSED) r |= SEL_RD;
		else if (pp->rdleft != 0 || pp->rdcum != 0) r |= SEL_RD;
		else if (pp->ocount > 0) r |= SEL_RD;	/* Actual data. */
	}

	return r;
}

/*===========================================================================*
 *				select_retry_pty			     *
 *===========================================================================*/
PUBLIC void select_retry_pty(tty_t *tp)
{
  	pty_t *pp = tp->tty_priv;
  	int r;

	/* See if the pty side of a pty is ready to return a select. */
	if (pp->select_ops && (r=select_try_pty(tp, pp->select_ops))) {
		pp->select_ops &= ~r;
		pp->select_ready_ops |= r;
		notify(pp->select_proc);
	}
}

/*===========================================================================*
 *				pty_select				     *
 *===========================================================================*/
PRIVATE int pty_select(tty_t *tp, message *m)
{
  	pty_t *pp = tp->tty_priv;
	int ops, ready_ops = 0, watch;

	ops = m->PROC_NR & (SEL_RD|SEL_WR|SEL_ERR);
	watch = (m->PROC_NR & SEL_NOTIFY) ? 1 : 0;

	ready_ops = select_try_pty(tp, ops);

	if (!ready_ops && ops && watch) {
		pp->select_ops |= ops;
		pp->select_proc = m->m_source;
	}

	return ready_ops;
}

#endif /* NR_PTYS > 0 */