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/* Timed low level locking for pthread library. NaCl version.
Copyright (C) 2015-2017 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/>. */
#include <assert.h>
#include <atomic.h>
#include <errno.h>
#include <lowlevellock.h>
#include <sys/time.h>
/* This behaves the same as the generic version in nptl/. It's simpler
because it doesn't need to convert an absolute timeout to a relative
one (and back again in the lll_futex_timed_wait macro). */
int
__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private)
{
/* Reject invalid timeouts. */
if (__glibc_unlikely (abstime->tv_nsec < 0)
|| __glibc_unlikely (abstime->tv_nsec >= 1000000000))
return EINVAL;
/* Try locking. */
while (atomic_exchange_acq (futex, 2) != 0)
{
/* If *futex == 2, wait until woken or timeout. */
int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex, 2,
abstime);
if (err != 0)
{
if (__glibc_likely (err == ETIMEDOUT))
return err;
assert (err == EAGAIN);
}
}
return 0;
}
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