hurd/ctty-output.c

   1 /* _hurd_ctty_output -- Do an output RPC and generate SIGTTOU if necessary.
   2 Copyright (C) 1995 Free Software Foundation, Inc.
   3 This file is part of the GNU C Library.
   4
   5 The GNU C Library is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 License, or (at your option) any later version.
   9
  10 The GNU C Library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <hurd.h>
  21 #include <hurd/signal.h>
  22
  23 /* Call *RPC on PORT and/or CTTY.  If a call on CTTY returns EBACKGROUND,
  24    generate SIGTTOU if appropriate.  */
  25
  26 error_t
  27 _hurd_ctty_output (io_t port, io_t ctty, error_t (*rpc) (io_t))
  28 {
  29   error_t err;
  30   struct hurd_sigstate *ss;
  31   io_t ioport;
  32
  33   /* Don't use the ctty io port if we are blocking or ignoring SIGTTOU.  */
  34   if (ctty == MACH_PORT_NULL)
  35     ioport = port;
  36   else
  37     {
  38       ss = _hurd_self_sigstate ();
  39       __spin_lock (&ss->lock);
  40       if (__sigismember (&ss->blocked, SIGTTOU) ||
  41           ss->actions[SIGTTOU].sa_handler == SIG_IGN)
  42         ioport = port;
  43       else
  44         ioport = ctty;
  45       __spin_unlock (&ss->lock);
  46     }
  47
  48   do
  49     {
  50       err = (*rpc) (ioport);
  51       if (ioport == ctty && err == EBACKGROUND)
  52         {
  53           if (_hurd_orphaned)
  54             /* Our process group is orphaned, so we never generate a
  55                signal; we just fail.  */
  56             err = EIO;
  57           else
  58             {
  59               /* Send a SIGTTOU signal to our process group.
  60
  61                  We must remember here not to clobber ERR, since
  62                  the loop condition below uses it to recall that
  63                  we should retry after a stop.  */
  64
  65               __USEPORT (CTTYID, _hurd_sig_post (0, SIGTTOU, port));
  66               /* XXX what to do if error here? */
  67
  68               /* At this point we should have just run the handler for
  69                  SIGTTOU or resumed after being stopped.  Now this is
  70                  still a "system call", so check to see if we should
  71                  restart it.  */
  72               __spin_lock (&ss->lock);
  73               if (!(ss->actions[SIGTTOU].sa_flags & SA_RESTART))
  74                 err = EINTR;
  75               __spin_unlock (&ss->lock);
  76             }
  77         }
  78       /* If the last RPC generated a SIGTTOU, loop to try it again.  */
  79     } while (err == EBACKGROUND);
  80
  81   return err;
  82 }