| /* Copyright (C) 2002-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include "pthreadP.h" |
| #include <atomic.h> |
| |
| |
| int |
| __pthread_setcancelstate (int state, int *oldstate) |
| { |
| volatile struct pthread *self; |
| |
| if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE) |
| return EINVAL; |
| |
| self = THREAD_SELF; |
| |
| int oldval = THREAD_GETMEM (self, cancelhandling); |
| while (1) |
| { |
| int newval = (state == PTHREAD_CANCEL_DISABLE |
| ? oldval | CANCELSTATE_BITMASK |
| : oldval & ~CANCELSTATE_BITMASK); |
| |
| /* Store the old value. */ |
| if (oldstate != NULL) |
| *oldstate = ((oldval & CANCELSTATE_BITMASK) |
| ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE); |
| |
| /* Avoid doing unnecessary work. The atomic operation can |
| potentially be expensive if the memory has to be locked and |
| remote cache lines have to be invalidated. */ |
| if (oldval == newval) |
| break; |
| |
| /* Update the cancel handling word. This has to be done |
| atomically since other bits could be modified as well. */ |
| int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
| oldval); |
| if (__glibc_likely (curval == oldval)) |
| { |
| if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) |
| __do_cancel (); |
| |
| break; |
| } |
| |
| /* Prepare for the next round. */ |
| oldval = curval; |
| } |
| |
| return 0; |
| } |
| strong_alias (__pthread_setcancelstate, pthread_setcancelstate) |
| hidden_def (__pthread_setcancelstate) |
