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