85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/* Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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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 <errno.h>
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#include <shlib-compat.h>
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#include "pthreadP.h"
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int
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__pthread_cond_destroy (cond)
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pthread_cond_t *cond;
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{
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int pshared = (cond->__data.__mutex == (void *) ~0l)
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? LLL_SHARED : LLL_PRIVATE;
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/* Make sure we are alone. */
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lll_lock (cond->__data.__lock, pshared);
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if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
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{
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/* If there are still some waiters which have not been
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woken up, this is an application bug. */
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lll_unlock (cond->__data.__lock, pshared);
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return EBUSY;
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}
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/* Tell pthread_cond_*wait that this condvar is being destroyed. */
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cond->__data.__total_seq = -1ULL;
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/* If there are waiters which have been already signalled or
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broadcasted, but still are using the pthread_cond_t structure,
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pthread_cond_destroy needs to wait for them. */
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unsigned int nwaiters = cond->__data.__nwaiters;
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if (nwaiters >= (1 << COND_NWAITERS_SHIFT))
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{
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/* Wake everybody on the associated mutex in case there are
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threads that have been requeued to it.
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Without this, pthread_cond_destroy could block potentially
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for a long time or forever, as it would depend on other
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thread's using the mutex.
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When all threads waiting on the mutex are woken up, pthread_cond_wait
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only waits for threads to acquire and release the internal
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condvar lock. */
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if (cond->__data.__mutex != NULL
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&& cond->__data.__mutex != (void *) ~0l)
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{
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pthread_mutex_t *mut = (pthread_mutex_t *) cond->__data.__mutex;
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lll_futex_wake (&mut->__data.__lock, INT_MAX,
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PTHREAD_MUTEX_PSHARED (mut));
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}
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do
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{
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lll_unlock (cond->__data.__lock, pshared);
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lll_futex_wait (&cond->__data.__nwaiters, nwaiters, pshared);
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lll_lock (cond->__data.__lock, pshared);
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nwaiters = cond->__data.__nwaiters;
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}
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while (nwaiters >= (1 << COND_NWAITERS_SHIFT));
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}
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return 0;
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}
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versioned_symbol (libpthread, __pthread_cond_destroy,
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pthread_cond_destroy, GLIBC_2_3_2);
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