/* _hurd_ctty_output -- Do an output RPC and generate SIGTTOU if necessary.

   Copyright (C) 1995-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <hurd.h>

#include <hurd/signal.h>

/* Call *RPC on PORT and/or CTTY.  If a call on CTTY returns EBACKGROUND,

   generate SIGTTOU if appropriate.  */

error_t

_hurd_ctty_output (io_t port, io_t ctty, error_t (*rpc) (io_t))

{

  if (ctty == MACH_PORT_NULL)

    return (*rpc) (port);

  else

    {

      struct hurd_sigstate *ss = _hurd_self_sigstate ();

      error_t err;

      do

	{

	  /* Don't use the ctty io port if we are blocking or ignoring

	     SIGTTOU.  We redo this check at the top of the loop in case

	     the signal handler changed the state.  */

	  __spin_lock (&ss->lock);

	  if (__sigismember (&ss->blocked, SIGTTOU) ||

	      ss->actions[SIGTTOU].sa_handler == SIG_IGN)

	    err = EIO;

	  else

	    err = 0;

	  __spin_unlock (&ss->lock);

	  if (err)

	    return (*rpc) (port);

	  err = (*rpc) (ctty);

	  if (err == EBACKGROUND)

	    {

	      if (_hurd_orphaned)

		/* Our process group is orphaned, so we never generate a

		   signal; we just fail.  */

		err = EIO;

	      else

		{

		  /* Send a SIGTTOU signal to our process group.

		     We must remember here not to clobber ERR, since

		     the loop condition below uses it to recall that

		  we should retry after a stop.  */

		  __USEPORT (CTTYID, _hurd_sig_post (0, SIGTTOU, port));

		  /* XXX what to do if error here? */

		  /* At this point we should have just run the handler for

		     SIGTTOU or resumed after being stopped.  Now this is

		     still a "system call", so check to see if we should

		  restart it.  */

		  __spin_lock (&ss->lock);

		  if (!(ss->actions[SIGTTOU].sa_flags & SA_RESTART))

		    err = EINTR;

		  __spin_unlock (&ss->lock);

		}

	    }

	  /* If the last RPC generated a SIGTTOU, loop to try it again.  */

	} while (err == EBACKGROUND);

      return err;

    }

}