hurd/thread-cancel.c

   1 /* Thread cancellation support.
   2 Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   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 Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <hurd/signal.h>
  21 #include <hurd/interrupt.h>
  22 #include <assert.h>
  23 #include <thread_state.h>
  24
  25
  26 /* See hurdsig.c.  */
  27 extern mach_port_t _hurdsig_abort_rpcs (struct hurd_sigstate *ss,
  28                                         int signo, int sigthread,
  29                                         struct machine_thread_all_state *,
  30                                         int *state_change,
  31                                         mach_port_t *reply_port,
  32                                         mach_msg_type_name_t reply_port_type,
  33                                         int untraced);
  34
  35 error_t
  36 hurd_thread_cancel (thread_t thread)
  37 {
  38   struct hurd_sigstate *ss = _hurd_thread_sigstate (thread);
  39   struct machine_thread_all_state state;
  40   int state_change;
  41   error_t err;
  42
  43   if (! ss)
  44     return EINVAL;
  45   if (ss == _hurd_self_sigstate ())
  46     return EINTR;               /* Bozo.  */
  47
  48   assert (! __spin_lock_locked (&ss->critical_section_lock));
  49   __spin_lock (&ss->critical_section_lock);
  50   __spin_lock (&ss->lock);
  51   err = __thread_suspend (thread);
  52   __spin_unlock (&ss->lock);
  53
  54   if (! err)
  55     {
  56       /* Set the flag telling the thread its operation is being cancelled.  */
  57       ss->cancel = 1;
  58
  59       /* Interrupt any interruptible RPC now in progress.  */
  60       state.set = 0;
  61       _hurdsig_abort_rpcs (ss, 0, 0, &state, &state_change, NULL, 0, 0);
  62       if (state_change)
  63         err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR,
  64                                   (natural_t *) &state.basic,
  65                                   MACHINE_THREAD_STATE_COUNT);
  66
  67       if (ss->cancel_hook)
  68         /* The code being cancelled has a special wakeup function.
  69            Calling this should make the thread wake up and check the
  70            cancellation flag.  */
  71         (*ss->cancel_hook) ();
  72
  73       __thread_resume (thread);
  74     }
  75
  76   _hurd_critical_section_unlock (ss);
  77   return err;
  78 }
  79
  80
  81 int
  82 hurd_check_cancel (void)
  83 {
  84   struct hurd_sigstate *ss = _hurd_self_sigstate ();
  85   int cancel;
  86
  87   __spin_lock (&ss->lock);
  88   assert (! __spin_lock_locked (&ss->critical_section_lock));
  89   cancel = ss->cancel;
  90   ss->cancel = 0;
  91   __spin_unlock (&ss->lock);
  92
  93   return cancel;
  94 }