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  #include <libc-lockP.h>
      22  
      23  int
      24  __pthread_setcancelstate (int state, int *oldstate)
      25  {
      26    volatile struct pthread *self;
      27  
      28    if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE)
      29      return EINVAL;
      30  
      31    self = THREAD_SELF;
      32  
      33    int oldval = atomic_load_relaxed (&self->cancelhandling);
      34    while (1)
      35      {
      36        int newval = (state == PTHREAD_CANCEL_DISABLE
      37  		    ? oldval | CANCELSTATE_BITMASK
      38  		    : oldval & ~CANCELSTATE_BITMASK);
      39  
      40        if (oldstate != NULL)
      41  	*oldstate = ((oldval & CANCELSTATE_BITMASK)
      42  		     ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
      43  
      44        if (oldval == newval)
      45  	break;
      46  
      47        if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
      48  						&oldval, newval))
      49  	{
      50  	  if (cancel_enabled_and_canceled_and_async (newval))
      51  	    __do_cancel ();
      52  
      53  	  break;
      54  	}
      55      }
      56  
      57    return 0;
      58  }
      59  libc_hidden_def (__pthread_setcancelstate)
      60  weak_alias (__pthread_setcancelstate, pthread_setcancelstate)