54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/* Timed low level locking for pthread library. NaCl version.
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Copyright (C) 2015-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <atomic.h>
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#include <errno.h>
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#include <lowlevellock.h>
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#include <sys/time.h>
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/* This behaves the same as the generic version in nptl/. It's simpler
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because it doesn't need to convert an absolute timeout to a relative
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one (and back again in the lll_futex_timed_wait macro). */
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int
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__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private)
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{
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/* Reject invalid timeouts. */
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if (__glibc_unlikely (abstime->tv_nsec < 0)
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|| __glibc_unlikely (abstime->tv_nsec >= 1000000000))
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return EINVAL;
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/* Try locking. */
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while (atomic_exchange_acq (futex, 2) != 0)
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{
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/* If *futex == 2, wait until woken or timeout. */
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int err = __nacl_irt_futex.futex_wait_abs ((volatile int *) futex, 2,
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abstime);
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if (err != 0)
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{
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if (__glibc_likely (err == ETIMEDOUT))
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return err;
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assert (err == EAGAIN);
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}
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}
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return 0;
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}
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