1  /* Copyright (C) 2002-2023 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     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include "pthreadP.h"
      20  #include <atomic.h>
      21  
      22  
      23  int
      24  __pthread_setcanceltype (int type, int *oldtype)
      25  {
      26    if (type < PTHREAD_CANCEL_DEFERRED || type > PTHREAD_CANCEL_ASYNCHRONOUS)
      27      return EINVAL;
      28  
      29    volatile struct pthread *self = THREAD_SELF;
      30  
      31    int oldval = atomic_load_relaxed (&self->cancelhandling);
      32    while (1)
      33      {
      34        int newval = (type == PTHREAD_CANCEL_ASYNCHRONOUS
      35  		    ? oldval | CANCELTYPE_BITMASK
      36  		    : oldval & ~CANCELTYPE_BITMASK);
      37  
      38        if (oldtype != NULL)
      39  	*oldtype = ((oldval & CANCELTYPE_BITMASK)
      40  		    ? PTHREAD_CANCEL_ASYNCHRONOUS : PTHREAD_CANCEL_DEFERRED);
      41  
      42        if (oldval == newval)
      43  	break;
      44  
      45        if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
      46  						&oldval, newval))
      47  	{
      48  	  if (cancel_enabled_and_canceled_and_async (newval))
      49  	    {
      50  	      THREAD_SETMEM (self, result, PTHREAD_CANCELED);
      51  	      __do_cancel ();
      52  	    }
      53  
      54  	  break;
      55  	}
      56      }
      57  
      58    return 0;
      59  }
      60  libc_hidden_def (__pthread_setcanceltype)
      61  weak_alias (__pthread_setcanceltype, pthread_setcanceltype)