| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 2002-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <errno.h> |
| 20 | #include "pthreadP.h" |
| 21 | #include <atomic.h> |
| 22 | |
| 23 | |
| 24 | int |
| 25 | __pthread_setcancelstate (state, oldstate) |
| 26 | int state; |
| 27 | int *oldstate; |
| 28 | { |
| 29 | volatile struct pthread *self; |
| 30 | |
| 31 | if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE) |
| 32 | return EINVAL; |
| 33 | |
| 34 | self = THREAD_SELF; |
| 35 | |
| 36 | int oldval = THREAD_GETMEM (self, cancelhandling); |
| 37 | while (1) |
| 38 | { |
| 39 | int newval = (state == PTHREAD_CANCEL_DISABLE |
| 40 | ? oldval | CANCELSTATE_BITMASK |
| 41 | : oldval & ~CANCELSTATE_BITMASK); |
| 42 | |
| 43 | /* Store the old value. */ |
| 44 | if (oldstate != NULL) |
| 45 | *oldstate = ((oldval & CANCELSTATE_BITMASK) |
| 46 | ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE); |
| 47 | |
| 48 | /* Avoid doing unnecessary work. The atomic operation can |
| 49 | potentially be expensive if the memory has to be locked and |
| 50 | remote cache lines have to be invalidated. */ |
| 51 | if (oldval == newval) |
| 52 | break; |
| 53 | |
| 54 | /* Update the cancel handling word. This has to be done |
| 55 | atomically since other bits could be modified as well. */ |
| 56 | int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, |
| 57 | oldval); |
| 58 | if (__glibc_likely (curval == oldval)) |
| 59 | { |
| 60 | if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) |
| 61 | __do_cancel (); |
| 62 | |
| 63 | break; |
| 64 | } |
| 65 | |
| 66 | /* Prepare for the next round. */ |
| 67 | oldval = curval; |
| 68 | } |
| 69 | |
| 70 | return 0; |
| 71 | } |
| 72 | strong_alias (__pthread_setcancelstate, pthread_setcancelstate) |