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/* Copyright (C) 2006-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
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 <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <sys/time.h>
#include <pthreadP.h>
#include <kernel-features.h>
int
__lll_robust_lock_wait (int *futex, int private)
{
int oldval = *futex;
int tid = THREAD_GETMEM (THREAD_SELF, tid);
/* If the futex changed meanwhile try locking again. */
if (oldval == 0)
goto try;
do
{
/* If the owner died, return the present value of the futex. */
if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
return oldval;
/* Try to put the lock into state 'acquired, possibly with waiters'. */
int newval = oldval | FUTEX_WAITERS;
if (oldval != newval
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
continue;
/* If *futex == 2, wait until woken. */
lll_futex_wait (futex, newval, private);
try:
;
}
while ((oldval = atomic_compare_and_exchange_val_acq (futex,
tid | FUTEX_WAITERS,
0)) != 0);
return 0;
}
int
__lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
int private)
{
/* Reject invalid timeouts. */
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
return EINVAL;
int tid = THREAD_GETMEM (THREAD_SELF, tid);
int oldval = *futex;
/* If the futex changed meanwhile, try locking again. */
if (oldval == 0)
goto try;
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely (abstime->tv_sec < 0))
return ETIMEDOUT;
do
{
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|| !defined lll_futex_timed_wait_bitset)
struct timeval tv;
struct timespec rt;
/* Get the current time. */
(void) __gettimeofday (&tv, NULL);
/* Compute relative timeout. */
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
if (rt.tv_nsec < 0)
{
rt.tv_nsec += 1000000000;
--rt.tv_sec;
}
/* Already timed out? */
if (rt.tv_sec < 0)
return ETIMEDOUT;
#endif
/* If the owner died, return the present value of the futex. */
if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
return oldval;
/* Try to put the lock into state 'acquired, possibly with waiters'. */
int newval = oldval | FUTEX_WAITERS;
if (oldval != newval
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
continue;
/* If *futex == 2, wait until woken or timeout. */
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|| !defined lll_futex_timed_wait_bitset)
lll_futex_timed_wait (futex, newval, &rt, private);
#else
int err = lll_futex_timed_wait_bitset (futex, newval, abstime,
FUTEX_CLOCK_REALTIME, private);
/* The futex call timed out. */
if (err == -ETIMEDOUT)
return -err;
#endif
try:
;
}
while ((oldval = atomic_compare_and_exchange_val_acq (futex,
tid | FUTEX_WAITERS,
0)) != 0);
return 0;
}
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