sysdeps/mach/hurd/sigsuspend.c

   1 /* Copyright (C) 1991-2016 Free Software Foundation, Inc.
   2
   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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <hurd.h>
  21 #include <hurd/signal.h>
  22 #include <hurd/msg.h>
  23
  24 /* Change the set of blocked signals to SET,
  25    wait until a signal arrives, and restore the set of blocked signals.  */
  26 int
  27 __sigsuspend (const sigset_t *set)
  28 {
  29   struct hurd_sigstate *ss;
  30   sigset_t newmask, oldmask, pending;
  31   mach_port_t wait;
  32   mach_msg_header_t msg;
  33
  34   if (set != NULL)
  35     /* Crash before locking.  */
  36     newmask = *set;
  37
  38   /* Get a fresh port we will wait on.  */
  39   wait = __mach_reply_port ();
  40
  41   ss = _hurd_self_sigstate ();
  42
  43   __spin_lock (&ss->lock);
  44
  45   oldmask = ss->blocked;
  46   if (set != NULL)
  47     /* Change to the new blocked signal mask.  */
  48     ss->blocked = newmask & ~_SIG_CANT_MASK;
  49
  50   /* Notice if any pending signals just became unblocked.  */
  51   pending = ss->pending & ~ss->blocked;
  52
  53   /* Tell the signal thread to message us when a signal arrives.  */
  54   ss->suspended = wait;
  55   __spin_unlock (&ss->lock);
  56
  57   if (pending)
  58     /* Tell the signal thread to check for pending signals.  */
  59     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  60
  61   /* Wait for the signal thread's message.  */
  62   __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
  63               MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
  64   __mach_port_destroy (__mach_task_self (), wait);
  65
  66   __spin_lock (&ss->lock);
  67   ss->blocked = oldmask;        /* Restore the old mask.  */
  68   pending = ss->pending & ~ss->blocked; /* Again check for pending signals.  */
  69   __spin_unlock (&ss->lock);
  70
  71   if (pending)
  72     /* Tell the signal thread to check for pending signals.  */
  73     __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
  74
  75   /* We've been interrupted!  And a good thing, too.
  76      Otherwise we'd never return.
  77      That's right; this function always returns an error.  */
  78   errno = EINTR;
  79   return -1;
  80 }
  81 libc_hidden_def (__sigsuspend)
  82 strong_alias (__sigsuspend, sigsuspend_not_cancel)
  83 weak_alias (__sigsuspend, sigsuspend)