sysdeps/mach/hurd/sigwait.c

   1 /* Copyright (C) 1996-2015 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <hurd.h>
  20 #include <hurd/signal.h>
  21 #include <hurd/msg.h>
  22 #include <hurd/sigpreempt.h>
  23 #include <assert.h>
  24
  25 /* Select any of pending signals from SET or wait for any to arrive.  */
  26 int
  27 __sigwait (const sigset_t *set, int *sig)
  28 {
  29   struct hurd_sigstate *ss;
  30   sigset_t mask, ready;
  31   int signo = 0;
  32   struct hurd_signal_preemptor preemptor;
  33   jmp_buf buf;
  34   mach_port_t wait;
  35   mach_msg_header_t msg;
  36
  37   sighandler_t
  38     preempt_fun (struct hurd_signal_preemptor *pe,
  39                  struct hurd_sigstate *ss,
  40                  int *sigp,
  41                  struct hurd_signal_detail *detail)
  42     {
  43       if (signo)
  44         /* We've already been run; don't interfere. */
  45         return SIG_ERR;
  46
  47       signo = *sigp;
  48
  49       /* Make sure this is all kosher */
  50       assert (__sigismember (&mask, signo));
  51
  52       /* Make sure this signal is unblocked */
  53       __sigdelset (&ss->blocked, signo);
  54
  55       return pe->handler;
  56     }
  57
  58   void
  59     handler (int sig)
  60     {
  61       assert (sig == signo);
  62       longjmp (buf, 1);
  63     }
  64
  65   wait = __mach_reply_port ();
  66
  67   if (set != NULL)
  68     /* Crash before locking */
  69     mask = *set;
  70   else
  71     __sigemptyset (&mask);
  72
  73   ss = _hurd_self_sigstate ();
  74   __spin_lock (&ss->lock);
  75
  76   /* See if one of these signals is currently pending.  */
  77   __sigandset (&ready, &ss->pending, &mask);
  78   if (! __sigisemptyset (&ready))
  79     {
  80       for (signo = 1; signo < NSIG; signo++)
  81         if (__sigismember (&ready, signo))
  82           {
  83             __sigdelset (&ready, signo);
  84             goto all_done;
  85           }
  86       /* Huh?  Where'd it go? */
  87       abort ();
  88     }
  89
  90   /* Wait for one of them to show up.  */
  91
  92   if (!setjmp (buf))
  93     {
  94       /* Make the preemptor */
  95       preemptor.signals = mask;
  96       preemptor.first = 0;
  97       preemptor.last = -1;
  98       preemptor.preemptor = preempt_fun;
  99       preemptor.handler = handler;
 100
 101       /* Install this preemptor */
 102       preemptor.next = ss->preemptors;
 103       ss->preemptors = &preemptor;
 104
 105       __spin_unlock (&ss->lock);
 106
 107       /* Wait. */
 108       __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
 109                   MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
 110       abort ();
 111     }
 112   else
 113     {
 114       assert (signo);
 115
 116       __spin_lock (&ss->lock);
 117
 118       /* Delete our preemptor. */
 119       assert (ss->preemptors == &preemptor);
 120       ss->preemptors = preemptor.next;
 121     }
 122
 123
 124 all_done:
 125   spin_unlock (&ss->lock);
 126
 127   __mach_port_destroy (__mach_task_self (), wait);
 128   *sig = signo;
 129   return 0;
 130 }
 131
 132 weak_alias (__sigwait, sigwait)