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/* Low-level locking access to futex facilities. NaCl version.
Copyright (C) 2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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/>. */
#ifndef _LOWLEVELLOCK_FUTEX_H
#define _LOWLEVELLOCK_FUTEX_H 1
#include <nacl-interfaces.h>
#include <time.h>
#pragma GCC diagnostic ignored "-Wunused-value" /* XXX */
/* Values for 'private' parameter of locking macros. Note pthreadP.h
optimizes for these exact values, though they are not required. */
#define LLL_PRIVATE 0
#define LLL_SHARED 128
#define FUTEX_PRIVATE_FLAG 0 /* XXX */
/* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP. */
#define lll_futex_wait(futexp, val, private) \
(- __nacl_irt_futex.futex_wait_abs ((volatile int *) (futexp), val, NULL))
/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses. */
#define lll_futex_timed_wait(futexp, val, timeout, private) \
({ \
/* This timeout is relative, but the IRT call wants it absolute. */ \
const struct timespec *_to = (timeout); \
struct timespec _ts; \
int _err = 0; \
if (_to != NULL \
&& __glibc_likely ((_err = __nacl_irt_clock.clock_gettime \
(CLOCK_REALTIME, &_ts)) == 0)) \
{ \
_ts.tv_sec -= _to->tv_sec; \
_ts.tv_nsec -= _to->tv_nsec; \
while (_ts.tv_nsec < 0) \
{ \
_ts.tv_nsec += 1000000000; \
--_ts.tv_sec; \
} \
_to = &_ts; \
} \
if (_err == 0) \
_err = __nacl_irt_futex.futex_wait_abs \
((volatile int *) (futexp), val, _to); \
-_err; \
})
/* Wake up up to NR waiters on FUTEXP. */
#define lll_futex_wake(futexp, nr, private) \
({ \
int _woken; \
- __nacl_irt_futex.futex_wake ((volatile int *) (futexp), nr, &_woken); \
})
/* NaCl does not support the requeue operation. The only use of this is in
pthread_cond_broadcast, which handles an error return by falling back to
plain lll_futex_wake. */
#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
((futexp), (nr_wake), (nr_move), (mutex), (val), (private), -ENOSYS)
/* NaCl does not support the special wake-unlock operation. The only use
of this is in pthread_cond_signal, which handles an error return by
falling back to plain lll_futex_wake. */
/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2. */
#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
((futexp), (nr_wake), (nr_wake2), (futexp2), (private), -ENOSYS)
#endif /* lowlevellock-futex.h */
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