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
__pthread_setcancelstate(int state,int * oldstate)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)
61