| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Low-level locking access to futex facilities. NaCl version. |
| 2 | Copyright (C) 2015 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 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 | #ifndef _LOWLEVELLOCK_FUTEX_H |
| 20 | #define _LOWLEVELLOCK_FUTEX_H 1 |
| 21 | |
| 22 | #include <nacl-interfaces.h> |
| 23 | #include <time.h> |
| 24 | |
| 25 | |
| 26 | #pragma GCC diagnostic ignored "-Wunused-value" /* XXX */ |
| 27 | |
| 28 | /* Values for 'private' parameter of locking macros. Note pthreadP.h |
| 29 | optimizes for these exact values, though they are not required. */ |
| 30 | #define LLL_PRIVATE 0 |
| 31 | #define LLL_SHARED 128 |
| 32 | |
| 33 | #define FUTEX_PRIVATE_FLAG 0 /* XXX */ |
| 34 | |
| 35 | |
| 36 | /* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP. */ |
| 37 | #define lll_futex_wait(futexp, val, private) \ |
| 38 | (- __nacl_irt_futex.futex_wait_abs ((volatile int *) (futexp), val, NULL)) |
| 39 | |
| 40 | /* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses. */ |
| 41 | #define lll_futex_timed_wait(futexp, val, timeout, private) \ |
| 42 | ({ \ |
| 43 | /* This timeout is relative, but the IRT call wants it absolute. */\ |
| 44 | const struct timespec *_to = (timeout); \ |
| 45 | struct timespec _ts; \ |
| 46 | int _err = 0; \ |
| 47 | if (_to != NULL \ |
| 48 | && __glibc_likely ((_err = __nacl_irt_clock.clock_gettime \ |
| 49 | (CLOCK_REALTIME, &_ts)) == 0)) \ |
| 50 | { \ |
| 51 | _ts.tv_sec += _to->tv_sec; \ |
| 52 | _ts.tv_nsec += _to->tv_nsec; \ |
| 53 | while (_ts.tv_nsec >= 1000000000) \ |
| 54 | { \ |
| 55 | _ts.tv_nsec -= 1000000000; \ |
| 56 | ++_ts.tv_sec; \ |
| 57 | } \ |
| 58 | _to = &_ts; \ |
| 59 | } \ |
| 60 | if (_err == 0) \ |
| 61 | _err = __nacl_irt_futex.futex_wait_abs \ |
| 62 | ((volatile int *) (futexp), val, _to); \ |
| 63 | -_err; \ |
| 64 | }) |
| 65 | |
| 66 | /* Wake up up to NR waiters on FUTEXP. */ |
| 67 | #define lll_futex_wake(futexp, nr, private) \ |
| 68 | ({ \ |
| 69 | int _woken; \ |
| 70 | - __nacl_irt_futex.futex_wake ((volatile int *) (futexp), nr, &_woken); \ |
| 71 | }) |
| 72 | |
| 73 | /* NaCl does not support the requeue operation. The only use of this is in |
| 74 | pthread_cond_broadcast, which handles an error return by falling back to |
| 75 | plain lll_futex_wake. */ |
| 76 | #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \ |
| 77 | ((futexp), (nr_wake), (nr_move), (mutex), (val), (private), -ENOSYS) |
| 78 | |
| 79 | /* NaCl does not support the special wake-unlock operation. The only use |
| 80 | of this is in pthread_cond_signal, which handles an error return by |
| 81 | falling back to plain lll_futex_wake. */ |
| 82 | /* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2. */ |
| 83 | #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \ |
| 84 | ((futexp), (nr_wake), (nr_wake2), (futexp2), (private), -ENOSYS) |
| 85 | |
| 86 | |
| 87 | #endif /* lowlevellock-futex.h */ |