/* Special protocol for terminal driver
   Copyright (C) 1991 Free Software Foundation

This file is part of the GNU Hurd.

The GNU Hurd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.

The GNU Hurd is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with the GNU Hurd; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* Written by Michael I. Bushnell.  */

subsystem term 28000;

#include <hurd/hurd_types.defs>

/* Find out what the controlling terminal ID port is.  */
term_getctty (
	terminal: io_t;
	out ctty: mach_port_make_send_t);

/* 
Return a controlling terminal port for this terminal.  This has the
following effects:

Certain input characters in certain modes will cause signals to be
sent to foreground processes which have made this call, on the sigpt
port they specified.  The ctty ID will be used as the reference port.

Certain conditions will cause SIGHUP to be sent using the same
mechanism as above.

When background processes do certain operations on a port returned by
term_become_ctty, the EBACKGROUND error may be returned.  This occurs
for io_read always, io_write if the appropriate bit is set in the
status, and various control operations always.  The vanilla port to
the terminal can still be used to do these operations.

A "foreground process" is one making a request over a port returned by
term_become_ctty whose pid (as provided in the term_become_ctty call)
matches the current owner (as set by io_mod_owner) or whose pgrp
matches the owner in the same fashion.  A "background process" is one
making a request over a port returned by term_become_ctty which is not
a foreground process.  */ 
term_become_ctty (
	terminal: io_t;
	pid: pid_t;
	pgrp: pid_t;
	sigpt: mach_port_t;
	out newtty: io_t);