hurd/msgportdemux.c

   1 /* Demux messages sent on the signal port.
   2    Copyright (C) 1991,92,94,95,97,99 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <hurd.h>
  21 #include <hurd/signal.h>
  22 #include <stddef.h>
  23
  24 struct demux
  25   {
  26     struct demux *next;
  27     boolean_t (*demux) (mach_msg_header_t *inp,
  28                         mach_msg_header_t *outp);
  29   };
  30
  31 struct demux *_hurd_msgport_demuxers = NULL;
  32
  33 extern boolean_t __msg_server (mach_msg_header_t *inp,
  34                                mach_msg_header_t *outp);
  35
  36 static boolean_t
  37 msgport_server (mach_msg_header_t *inp,
  38                 mach_msg_header_t *outp)
  39 {
  40   extern boolean_t _S_msg_server (mach_msg_header_t *inp,
  41                                   mach_msg_header_t *outp);
  42   extern boolean_t _S_exc_server (mach_msg_header_t *inp,
  43                                   mach_msg_header_t *outp);
  44   struct demux *d;
  45
  46   for (d = _hurd_msgport_demuxers; d != NULL; d = d->next)
  47     if ((*d->demux) (inp, outp))
  48       return 1;
  49
  50   return (_S_exc_server (inp, outp) ||
  51           _S_msg_server (inp, outp));
  52 }
  53
  54 /* This is the code that the signal thread runs.  */
  55 void
  56 _hurd_msgport_receive (void)
  57 {
  58   /* Get our own sigstate cached so we never again have to take a lock to
  59      fetch it.  There is much code in hurdsig.c that operates with some
  60      sigstate lock held, which will deadlock with _hurd_thread_sigstate.
  61
  62      Furthermore, in the cthreads case this is the convenient spot
  63      to initialize _hurd_msgport_thread (see hurdsig.c:_hurdsig_init).  */
  64
  65   _hurd_msgport_thread = _hurd_self_sigstate ()->thread;
  66
  67   while (1)
  68     (void) __mach_msg_server (msgport_server, __vm_page_size, _hurd_msgport);
  69 }