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/* sem_timedwait -- wait on a semaphore. Generic futex-using version.
Copyright (C) 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <internaltypes.h>
#include <semaphore.h>
#include <pthreadP.h>
int
sem_timedwait (sem_t *sem, const struct timespec *abstime)
{
/* First check for cancellation. */
CANCELLATION_P (THREAD_SELF);
int *futex = (int *) sem;
int val;
int err;
if (*futex > 0)
{
val = atomic_decrement_if_positive (futex);
if (val > 0)
return 0;
}
err = -EINVAL;
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
goto error_return;
do
{
struct timeval tv;
struct timespec rt;
int sec, nsec;
/* Get the current time. */
gettimeofday (&tv, NULL);
/* Compute relative timeout. */
sec = abstime->tv_sec - tv.tv_sec;
nsec = abstime->tv_nsec - tv.tv_usec * 1000;
if (nsec < 0)
{
nsec += 1000000000;
--sec;
}
/* Already timed out? */
err = -ETIMEDOUT;
if (sec < 0)
goto error_return;
/* Do wait. */
rt.tv_sec = sec;
rt.tv_nsec = nsec;
/* Enable asynchronous cancellation. Required by the standard. */
int oldtype = __pthread_enable_asynccancel ();
err = lll_futex_timed_wait (futex, 0, &rt);
/* Disable asynchronous cancellation. */
__pthread_disable_asynccancel (oldtype);
if (err != 0 && err != -EWOULDBLOCK)
goto error_return;
val = atomic_decrement_if_positive (futex);
}
while (val <= 0);
return 0;
error_return:
__set_errno (-err);
return -1;
}
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