sysdeps/mach/hurd/sigsuspend.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <hurd.h>
  22 #include <hurd/signal.h>
  23 #include <hurd/msg.h>
  24
  25 /* Change the set of blocked signals to SET,
  26    wait until a signal arrives, and restore the set of blocked signals.  */
  27 int
  28 DEFUN(sigsuspend, (set), CONST sigset_t *set)
  29 {
  30   struct hurd_sigstate *ss;
  31   sigset_t newmask, oldmask, pending;
  32   mach_port_t wait;
  33   mach_msg_header_t msg;
  34
  35   if (set != NULL)
  36     /* Crash before locking.  */
  37     newmask = *set;
  38
  39   /* Get a fresh port we will wait on.  */
  40   wait = __mach_reply_port ();
  41
  42   ss = _hurd_self_sigstate ();
  43
  44   __spin_lock (&ss->lock);
  45
  46   oldmask = ss->blocked;
  47   if (set != NULL)
  48     /* Change to the new blocked signal mask.  */
  49     ss->blocked = newmask & ~_SIG_CANT_MASK;
  50
  51   /* Notice if any pending signals just became unblocked.  */
  52   pending = ss->pending & ~ss->blocked;
  53
  54   /* Tell the signal thread to message us when a signal arrives.  */
  55   ss->suspended = wait;
  56   __spin_unlock (&ss->lock);
  57
  58   if (pending)
  59     /* Tell the signal thread to check for pending signals.  */
  60     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  61
  62   /* Wait for the signal thread's message.  */
  63   __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
  64               MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
  65   __mach_port_destroy (__mach_task_self (), wait);
  66
  67   __spin_lock (&ss->lock);
  68   ss->blocked = oldmask;        /* Restore the old mask.  */
  69   pending = ss->pending & ~ss->blocked; /* Again check for pending signals.  */
  70   __spin_unlock (&ss->lock);
  71
  72   if (pending)
  73     /* Tell the signal thread to check for pending signals.  */
  74     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  75
  76   /* We've been interrupted!  And a good thing, too.
  77      Otherwise we'd never return.
  78      That's right; this function always returns an error.  */
  79   errno = EINTR;
  80   return -1;
  81 }