1: /* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
    2:    This file is part of the GNU C Library.
    3:    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
    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 <setjmp.h>
   21: #include <stdlib.h>
   22: #include "pthreadP.h"
   23: 
   24: 
   25: /* The next two functions are similar to pthread_setcanceltype() but
   26:    more specialized for the use in the cancelable functions like write().
   27:    They do not need to check parameters etc.  */
   28: int
   29: attribute_hidden
   30: __pthread_enable_asynccancel (void)
   31: {
   32:   struct pthread *self = THREAD_SELF;
   33:   int oldval = THREAD_GETMEM (self, cancelhandling);
   34: 
   35:   while (1)
   36:     {
   37:       int newval = oldval | CANCELTYPE_BITMASK;
   38: 
   39:       if (newval == oldval)
   40:         break;
   41: 
   42:       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
   43:                                               oldval);
   44:       if (__builtin_expect (curval == oldval, 1))
   45:         {
   46:           if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
   47:             {
   48:               THREAD_SETMEM (self, result, PTHREAD_CANCELED);
   49:               __do_cancel ();
   50:             }
   51: 
   52:           break;
   53:         }
   54: 
   55:       /* Prepare the next round.  */
   56:       oldval = curval;
   57:     }
   58: 
   59:   return oldval;
   60: }
   61: 
   62: 
   63: void
   64: internal_function attribute_hidden
   65: __pthread_disable_asynccancel (int oldtype)
   66: {
   67:   /* If asynchronous cancellation was enabled before we do not have
   68:      anything to do.  */
   69:   if (oldtype & CANCELTYPE_BITMASK)
   70:     return;
   71: 
   72:   struct pthread *self = THREAD_SELF;
   73:   int oldval = THREAD_GETMEM (self, cancelhandling);
   74: 
   75:   while (1)
   76:     {
   77:       int newval = oldval & ~CANCELTYPE_BITMASK;
   78: 
   79:       if (newval == oldval)
   80:         break;
   81: 
   82:       int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
   83:                                               oldval);
   84:       if (__builtin_expect (curval == oldval, 1))
   85:         break;
   86: 
   87:       /* Prepare the next round.  */
   88:       oldval = curval;
   89:     }
   90: }