Blame hurd/msgportdemux.c

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/* Demux messages sent on the signal port.
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   Copyright (C) 1991-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.  */
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#include <hurd.h>
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#include <hurd/signal.h>
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#include <stddef.h>
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struct demux
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  {
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    struct demux *next;
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    boolean_t (*demux) (mach_msg_header_t *inp,
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			mach_msg_header_t *outp);
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  };
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struct demux *_hurd_msgport_demuxers = NULL;
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extern boolean_t __msg_server (mach_msg_header_t *inp,
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			       mach_msg_header_t *outp);
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static boolean_t
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msgport_server (mach_msg_header_t *inp,
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		mach_msg_header_t *outp)
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{
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  extern boolean_t _S_msg_server (mach_msg_header_t *inp,
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				  mach_msg_header_t *outp);
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  extern boolean_t _S_exc_server (mach_msg_header_t *inp,
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				  mach_msg_header_t *outp);
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  struct demux *d;
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  for (d = _hurd_msgport_demuxers; d != NULL; d = d->next)
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    if ((*d->demux) (inp, outp))
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      return 1;
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  return (_S_exc_server (inp, outp) ||
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	  _S_msg_server (inp, outp));
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}
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/* This is the code that the signal thread runs.  */
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void
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_hurd_msgport_receive (void)
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{
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  /* Get our own sigstate cached so we never again have to take a lock to
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     fetch it.  There is much code in hurdsig.c that operates with some
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     sigstate lock held, which will deadlock with _hurd_thread_sigstate.
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     Furthermore, in the cthreads case this is the convenient spot
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     to initialize _hurd_msgport_thread (see hurdsig.c:_hurdsig_init).  */
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  _hurd_msgport_thread = _hurd_self_sigstate ()->thread;
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  while (1)
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    (void) __mach_msg_server (msgport_server, __vm_page_size, _hurd_msgport);
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}