nptl/pthread_setcanceltype.c

   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)