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/* low level locking for pthread library. Generic futex-using version.
Copyright (C) 2003-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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 <atomic.h>
void
__lll_lock_wait_private (int *futex)
{
if (*futex == 2)
lll_futex_wait (futex, 2, LLL_PRIVATE);
while (atomic_exchange_acq (futex, 2) != 0)
lll_futex_wait (futex, 2, LLL_PRIVATE);
}
/* These functions don't get included in libc.so */
#if IS_IN (libpthread)
void
__lll_lock_wait (int *futex, int private)
{
if (*futex == 2)
lll_futex_wait (futex, 2, private);
while (atomic_exchange_acq (futex, 2) != 0)
lll_futex_wait (futex, 2, private);
}
int
__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private)
{
/* Reject invalid timeouts. */
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
return EINVAL;
/* Try locking. */
while (atomic_exchange_acq (futex, 2) != 0)
{
struct timeval tv;
/* Get the current time. */
(void) __gettimeofday (&tv, NULL);
/* Compute relative timeout. */
struct timespec rt;
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;
}
if (rt.tv_sec < 0)
return ETIMEDOUT;
/* Wait. */
lll_futex_timed_wait (futex, 2, &rt, private);
}
return 0;
}
int
__lll_timedwait_tid (int *tidp, const struct timespec *abstime)
{
int tid;
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
return EINVAL;
/* Repeat until thread terminated. */
while ((tid = *tidp) != 0)
{
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;
/* Wait until thread terminates. The kernel so far does not use
the private futex operations for this. */
if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
return ETIMEDOUT;
}
return 0;
}
#endif
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