sysdeps/mach/hurd/sigsuspend.c

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2002, 2007
   2      Free Software Foundation, Inc.
   3
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  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 __sigsuspend (set)
  29      const sigset_t *set;
  30 {
  31   struct hurd_sigstate *ss;
  32   sigset_t newmask, oldmask, pending;
  33   mach_port_t wait;
  34   mach_msg_header_t msg;
  35
  36   if (set != NULL)
  37     /* Crash before locking.  */
  38     newmask = *set;
  39
  40   /* Get a fresh port we will wait on.  */
  41   wait = __mach_reply_port ();
  42
  43   ss = _hurd_self_sigstate ();
  44
  45   __spin_lock (&ss->lock);
  46
  47   oldmask = ss->blocked;
  48   if (set != NULL)
  49     /* Change to the new blocked signal mask.  */
  50     ss->blocked = newmask & ~_SIG_CANT_MASK;
  51
  52   /* Notice if any pending signals just became unblocked.  */
  53   pending = ss->pending & ~ss->blocked;
  54
  55   /* Tell the signal thread to message us when a signal arrives.  */
  56   ss->suspended = wait;
  57   __spin_unlock (&ss->lock);
  58
  59   if (pending)
  60     /* Tell the signal thread to check for pending signals.  */
  61     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  62
  63   /* Wait for the signal thread's message.  */
  64   __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
  65               MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
  66   __mach_port_destroy (__mach_task_self (), wait);
  67
  68   __spin_lock (&ss->lock);
  69   ss->blocked = oldmask;        /* Restore the old mask.  */
  70   pending = ss->pending & ~ss->blocked; /* Again check for pending signals.  */
  71   __spin_unlock (&ss->lock);
  72
  73   if (pending)
  74     /* Tell the signal thread to check for pending signals.  */
  75     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  76
  77   /* We've been interrupted!  And a good thing, too.
  78      Otherwise we'd never return.
  79      That's right; this function always returns an error.  */
  80   errno = EINTR;
  81   return -1;
  82 }
  83 libc_hidden_def (__sigsuspend)
  84 strong_alias (__sigsuspend, sigsuspend_not_cancel)
  85 weak_alias (__sigsuspend, sigsuspend)