nptl/pthread_setcancelstate.c

   1 /* Copyright (C) 2002-2022 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)