glibc/hurd/ctty-input.c

/* _hurd_ctty_input -- Do an input RPC and generate SIGTTIN if necessary.
   Copyright (C) 1995, 1997 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <hurd.h>
#include <hurd/signal.h>

/* Call *RPC on PORT and/or CTTY.  If a call on CTTY returns EBACKGROUND,
   generate SIGTTIN or EIO as appropriate.  */

error_t
_hurd_ctty_input (io_t port, io_t ctty, error_t (*rpc) (io_t))
{
  error_t err;

  do
    {
      err = (*rpc) (ctty != MACH_PORT_NULL ? ctty : port);
      if (ctty != MACH_PORT_NULL && err == EBACKGROUND)
	{
	  /* We are a background job and tried to read from the tty.
	     We should probably get a SIGTTIN signal.  */
	  struct hurd_sigstate *ss;
	  if (_hurd_orphaned)
	    /* Our process group is orphaned.  Don't stop; just fail.  */
	    err = EIO;
	  else
	    {
	      ss = _hurd_self_sigstate ();
	      __spin_lock (&ss->lock);
	      if (__sigismember (&ss->blocked, SIGTTIN) ||
		  ss->actions[SIGTTIN].sa_handler == SIG_IGN)
		/* We are blocking or ignoring SIGTTIN.  Just fail.  */
		err = EIO;
	      __spin_unlock (&ss->lock);
	    }
	  if (err == EBACKGROUND)
	    {
	      /* Send a SIGTTIN 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, SIGTTIN, port));
	      /* XXX what to do if error here? */

	      /* At this point we should have just run the handler for
		 SIGTTIN 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[SIGTTIN].sa_flags & SA_RESTART))
		err = EINTR;
	      __spin_unlock (&ss->lock);
	    }
	}
      /* If the last RPC generated a SIGTTIN, loop to try it again.  */
    } while (err == EBACKGROUND);

  return err;
}