1: /* Thread cancellation support.
    2:    Copyright (C) 1995, 1996, 1997, 2000 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 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, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 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:     {
   47:       /* We are cancelling ourselves, so it is easy to succeed
   48:          quickly.  Since this function is not a cancellation point, we
   49:          just leave the flag set pending the next cancellation point
   50:          (hurd_check_cancel or RPC) and return success.  */
   51:       ss->cancel = 1;
   52:       return 0;
   53:     }
   54: 
   55:   assert (! __spin_lock_locked (&ss->critical_section_lock));
   56:   __spin_lock (&ss->critical_section_lock);
   57:   __spin_lock (&ss->lock);
   58:   err = __thread_suspend (thread);
   59:   __spin_unlock (&ss->lock);
   60: 
   61:   if (! err)
   62:     {
   63:       /* Set the flag telling the thread its operation is being cancelled.  */
   64:       ss->cancel = 1;
   65: 
   66:       /* Interrupt any interruptible RPC now in progress.  */
   67:       state.set = 0;
   68:       _hurdsig_abort_rpcs (ss, 0, 0, &state, &state_change, NULL, 0, 0);
   69:       if (state_change)
   70:         err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR,
   71:                                   (natural_t *) &state.basic,
   72:                                   MACHINE_THREAD_STATE_COUNT);
   73: 
   74:       if (ss->cancel_hook)
   75:         /* The code being cancelled has a special wakeup function.
   76:            Calling this should make the thread wake up and check the
   77:            cancellation flag.  */
   78:         (*ss->cancel_hook) ();
   79: 
   80:       __thread_resume (thread);
   81:     }
   82: 
   83:   _hurd_critical_section_unlock (ss);
   84:   return err;
   85: }
   86: 
   87: 
   88: int
   89: hurd_check_cancel (void)
   90: {
   91:   struct hurd_sigstate *ss = _hurd_self_sigstate ();
   92:   int cancel;
   93: 
   94:   __spin_lock (&ss->lock);
   95:   assert (! __spin_lock_locked (&ss->critical_section_lock));
   96:   cancel = ss->cancel;
   97:   ss->cancel = 0;
   98:   __spin_unlock (&ss->lock);
   99: 
  100:   return cancel;
  101: }