sysdeps/mach/hurd/sigwait.c

   1 /* Copyright (C) 1996,97,2001,02 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <hurd.h>
  21 #include <hurd/signal.h>
  22 #include <hurd/msg.h>
  23 #include <hurd/sigpreempt.h>
  24 #include <assert.h>
  25
  26 /* Select any of pending signals from SET or wait for any to arrive.  */
  27 int
  28 __sigwait (const sigset_t *set, int *sig)
  29 {
  30   struct hurd_sigstate *ss;
  31   sigset_t mask, ready;
  32   int signo = 0;
  33   struct hurd_signal_preemptor preemptor;
  34   jmp_buf buf;
  35   mach_port_t wait;
  36   mach_msg_header_t msg;
  37
  38   sighandler_t
  39     preempt_fun (struct hurd_signal_preemptor *pe,
  40                  struct hurd_sigstate *ss,
  41                  int *sigp,
  42                  struct hurd_signal_detail *detail)
  43     {
  44       if (signo)
  45         /* We've already been run; don't interfere. */
  46         return SIG_ERR;
  47
  48       signo = *sigp;
  49
  50       /* Make sure this is all kosher */
  51       assert (__sigismember (&mask, signo));
  52
  53       /* Make sure this signal is unblocked */
  54       __sigdelset (&ss->blocked, signo);
  55
  56       return pe->handler;
  57     }
  58
  59   void
  60     handler (int sig)
  61     {
  62       assert (sig == signo);
  63       longjmp (buf, 1);
  64     }
  65
  66   wait = __mach_reply_port ();
  67
  68   if (set != NULL)
  69     /* Crash before locking */
  70     mask = *set;
  71   else
  72     __sigemptyset (&mask);
  73
  74   ss = _hurd_self_sigstate ();
  75   __spin_lock (&ss->lock);
  76
  77   /* See if one of these signals is currently pending.  */
  78   __sigandset (&ready, &ss->pending, &mask);
  79   if (! __sigisemptyset (&ready))
  80     {
  81       for (signo = 1; signo < NSIG; signo++)
  82         if (__sigismember (&ready, signo))
  83           {
  84             __sigdelset (&ready, signo);
  85             goto all_done;
  86           }
  87       /* Huh?  Where'd it go? */
  88       abort ();
  89     }
  90
  91   /* Wait for one of them to show up.  */
  92
  93   if (!setjmp (buf))
  94     {
  95       /* Make the preemptor */
  96       preemptor.signals = mask;
  97       preemptor.first = 0;
  98       preemptor.last = -1;
  99       preemptor.preemptor = preempt_fun;
 100       preemptor.handler = handler;
 101
 102       /* Install this preemptor */
 103       preemptor.next = ss->preemptors;
 104       ss->preemptors = &preemptor;
 105
 106       __spin_unlock (&ss->lock);
 107
 108       /* Wait. */
 109       __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
 110                   MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
 111       abort ();
 112     }
 113   else
 114     {
 115       assert (signo);
 116
 117       __spin_lock (&ss->lock);
 118
 119       /* Delete our preemptor. */
 120       assert (ss->preemptors == &preemptor);
 121       ss->preemptors = preemptor.next;
 122     }
 123
 124
 125 all_done:
 126   spin_unlock (&ss->lock);
 127
 128   __mach_port_destroy (__mach_task_self (), wait);
 129   *sig = signo;
 130   return 0;
 131 }
 132
 133 weak_alias (__sigwait, sigwait)