405 lines
11 KiB
C
405 lines
11 KiB
C
/* $NetBSD: pthread_cond.c,v 1.7 2003/02/15 04:38:33 nathanw Exp $ */
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/*-
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* Copyright (c) 2001 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nathan J. Williams.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <errno.h>
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#include <sys/cdefs.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include "pthread.h"
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#include "pthread_int.h"
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#ifdef PTHREAD_COND_DEBUG
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#define SDPRINTF(x) DPRINTF(x)
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#else
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#define SDPRINTF(x)
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#endif
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int _sys_select(int, fd_set *, fd_set *, fd_set *, struct timeval *);
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extern int pthread__started;
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static void pthread_cond_wait__callback(void *);
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static int pthread_cond_wait_nothread(pthread_t, pthread_mutex_t *,
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const struct timespec *);
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__strong_alias(__libc_cond_init,pthread_cond_init)
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__strong_alias(__libc_cond_signal,pthread_cond_signal)
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__strong_alias(__libc_cond_broadcast,pthread_cond_broadcast)
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__strong_alias(__libc_cond_wait,pthread_cond_wait)
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__strong_alias(__libc_cond_timedwait,pthread_cond_timedwait)
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__strong_alias(__libc_cond_destroy,pthread_cond_destroy)
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int
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pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
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{
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#ifdef ERRORCHECK
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if ((cond == NULL) ||
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(attr && (attr->ptca_magic != _PT_CONDATTR_MAGIC)))
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return EINVAL;
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#endif
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cond->ptc_magic = _PT_COND_MAGIC;
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pthread_lockinit(&cond->ptc_lock);
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PTQ_INIT(&cond->ptc_waiters);
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cond->ptc_mutex = NULL;
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return 0;
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}
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int
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pthread_cond_destroy(pthread_cond_t *cond)
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{
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#ifdef ERRORCHECK
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if ((cond == NULL) || (cond->ptc_magic != _PT_COND_MAGIC) ||
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(cond->ptc_mutex != NULL) ||
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(cond->ptc_lock != __SIMPLELOCK_UNLOCKED))
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return EINVAL;
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#endif
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cond->ptc_magic = _PT_COND_DEAD;
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return 0;
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}
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int
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pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
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{
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pthread_t self;
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#ifdef ERRORCHECK
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if ((cond == NULL) || (cond->ptc_magic != _PT_COND_MAGIC) ||
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(mutex == NULL) || (mutex->ptm_magic != _PT_MUTEX_MAGIC))
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return EINVAL;
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#endif
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self = pthread__self();
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PTHREADD_ADD(PTHREADD_COND_WAIT);
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/* Just hang out for a while if threads aren't running yet. */
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if (__predict_false(pthread__started == 0))
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return pthread_cond_wait_nothread(self, mutex, NULL);
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pthread_spinlock(self, &cond->ptc_lock);
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#ifdef ERRORCHECK
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if (cond->ptc_mutex == NULL)
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cond->ptc_mutex = mutex;
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else {
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if (cond->ptc_mutex != mutex) {
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pthread_spinunlock(self, &cond->ptc_lock);
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return EINVAL;
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}
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/* Check the mutex is actually locked */
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if (mutex->ptm_lock != __SIMPLELOCK_LOCKED) {
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pthread_spinunlock(self, &cond->ptc_lock);
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return EPERM;
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}
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}
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#endif
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SDPRINTF(("(cond wait %p) Waiting on %p, mutex %p\n",
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self, cond, mutex));
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pthread_spinlock(self, &self->pt_statelock);
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if (self->pt_cancel) {
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pthread_spinunlock(self, &self->pt_statelock);
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pthread_spinunlock(self, &cond->ptc_lock);
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pthread_exit(PTHREAD_CANCELED);
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}
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self->pt_state = PT_STATE_BLOCKED_QUEUE;
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self->pt_sleepobj = cond;
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self->pt_sleepq = &cond->ptc_waiters;
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self->pt_sleeplock = &cond->ptc_lock;
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pthread_spinunlock(self, &self->pt_statelock);
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PTQ_INSERT_TAIL(&cond->ptc_waiters, self, pt_sleep);
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pthread_mutex_unlock(mutex);
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pthread__block(self, &cond->ptc_lock);
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/* Spinlock is unlocked on return */
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pthread_mutex_lock(mutex);
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pthread__testcancel(self);
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SDPRINTF(("(cond wait %p) Woke up on %p, mutex %p\n",
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self, cond, mutex));
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return 0;
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}
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struct pthread_cond__waitarg {
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pthread_t ptw_thread;
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pthread_cond_t *ptw_cond;
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};
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int
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pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
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const struct timespec *abstime)
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{
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pthread_t self;
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struct pthread_cond__waitarg wait;
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struct pt_alarm_t alarm;
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int retval;
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#ifdef ERRORCHECK
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if ((cond == NULL) || (cond->ptc_magic != _PT_COND_MAGIC) ||
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(mutex == NULL) || (mutex->ptm_magic != _PT_MUTEX_MAGIC))
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return EINVAL;
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if ((abstime == NULL) || (abstime->tv_sec < 0 ||
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abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
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return EINVAL;
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#endif
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self = pthread__self();
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PTHREADD_ADD(PTHREADD_COND_TIMEDWAIT);
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/* Just hang out for a while if threads aren't running yet. */
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if (__predict_false(pthread__started == 0))
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return pthread_cond_wait_nothread(self, mutex, abstime);
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pthread_spinlock(self, &cond->ptc_lock);
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#ifdef ERRORCHECK
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if (cond->ptc_mutex == NULL)
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cond->ptc_mutex = mutex;
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else {
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if (cond->ptc_mutex != mutex) {
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pthread_spinunlock(self, &cond->ptc_lock);
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return EINVAL;
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}
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/* Check the mutex is actually locked */
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if (mutex->ptm_lock != __SIMPLELOCK_LOCKED) {
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pthread_spinunlock(self, &cond->ptc_lock);
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return EPERM;
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}
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}
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#endif
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wait.ptw_thread = self;
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wait.ptw_cond = cond;
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retval = 0;
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SDPRINTF(("(cond timed wait %p) Waiting on %p until %d.%06ld\n",
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self, cond, abstime->tv_sec, abstime->tv_nsec/1000));
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pthread_spinlock(self, &self->pt_statelock);
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if (self->pt_cancel) {
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pthread_spinunlock(self, &self->pt_statelock);
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pthread_spinunlock(self, &cond->ptc_lock);
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pthread_exit(PTHREAD_CANCELED);
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}
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pthread__alarm_add(self, &alarm, abstime, pthread_cond_wait__callback,
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&wait);
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self->pt_state = PT_STATE_BLOCKED_QUEUE;
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self->pt_sleepobj = cond;
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self->pt_sleepq = &cond->ptc_waiters;
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self->pt_sleeplock = &cond->ptc_lock;
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pthread_spinunlock(self, &self->pt_statelock);
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PTQ_INSERT_TAIL(&cond->ptc_waiters, self, pt_sleep);
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pthread_mutex_unlock(mutex);
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pthread__block(self, &cond->ptc_lock);
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/* Spinlock is unlocked on return */
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SDPRINTF(("(cond timed wait %p) Woke up on %p, mutex %p\n",
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self, cond));
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pthread__alarm_del(self, &alarm);
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if (pthread__alarm_fired(&alarm))
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retval = ETIMEDOUT;
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SDPRINTF(("(cond timed wait %p) %s\n",
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self, (retval == ETIMEDOUT) ? "(timed out)" : ""));
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pthread_mutex_lock(mutex);
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pthread__testcancel(self);
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return retval;
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}
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static void
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pthread_cond_wait__callback(void *arg)
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{
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struct pthread_cond__waitarg *a;
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pthread_t self;
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a = arg;
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self = pthread__self();
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/*
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* Don't dequeue and schedule the thread if it's already been
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* queued up by a signal or broadcast (but hasn't yet run as far
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* as pthread__alarm_del(), or we wouldn't be here, and hence can't
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* have become blocked on some *other* queue).
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*/
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pthread_spinlock(self, &a->ptw_cond->ptc_lock);
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if (a->ptw_thread->pt_state == PT_STATE_BLOCKED_QUEUE) {
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PTQ_REMOVE(&a->ptw_cond->ptc_waiters, a->ptw_thread, pt_sleep);
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#ifdef ERRORCHECK
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if (PTQ_EMPTY(&a->ptw_cond->ptc_waiters))
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a->ptw_cond->ptc_mutex = NULL;
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#endif
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pthread__sched(self, a->ptw_thread);
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}
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pthread_spinunlock(self, &a->ptw_cond->ptc_lock);
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}
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int
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pthread_cond_signal(pthread_cond_t *cond)
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{
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pthread_t self, signaled;
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#ifdef ERRORCHECK
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if ((cond == NULL) || (cond->ptc_magic != _PT_COND_MAGIC))
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return EINVAL;
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#endif
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PTHREADD_ADD(PTHREADD_COND_SIGNAL);
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SDPRINTF(("(cond signal %p) Signaling %p\n",
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pthread__self(), cond));
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if (!PTQ_EMPTY(&cond->ptc_waiters)) {
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self = pthread__self();
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pthread_spinlock(self, &cond->ptc_lock);
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signaled = PTQ_FIRST(&cond->ptc_waiters);
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if (signaled != NULL)
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PTQ_REMOVE(&cond->ptc_waiters, signaled, pt_sleep);
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#ifdef ERRORCHECK
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if (PTQ_EMPTY(&cond->ptc_waiters))
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cond->ptc_mutex = NULL;
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#endif
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pthread_spinunlock(self, &cond->ptc_lock);
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if (signaled != NULL) {
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pthread__sched(self, signaled);
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PTHREADD_ADD(PTHREADD_COND_WOKEUP);
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}
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}
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return 0;
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}
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int
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pthread_cond_broadcast(pthread_cond_t *cond)
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{
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pthread_t self;
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struct pthread_queue_t blockedq;
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#ifdef ERRORCHECK
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if ((cond == NULL) || (cond->ptc_magic != _PT_COND_MAGIC))
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return EINVAL;
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#endif
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PTHREADD_ADD(PTHREADD_COND_BROADCAST);
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SDPRINTF(("(cond signal %p) Broadcasting %p\n",
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pthread__self(), cond));
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if (!PTQ_EMPTY(&cond->ptc_waiters)) {
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self = pthread__self();
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pthread_spinlock(self, &cond->ptc_lock);
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blockedq = cond->ptc_waiters;
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PTQ_INIT(&cond->ptc_waiters);
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#ifdef ERRORCHECK
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cond->ptc_mutex = NULL;
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#endif
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pthread_spinunlock(self, &cond->ptc_lock);
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pthread__sched_sleepers(self, &blockedq);
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PTHREADD_ADD(PTHREADD_COND_WOKEUP);
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}
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return 0;
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}
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int
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pthread_condattr_init(pthread_condattr_t *attr)
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{
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#ifdef ERRORCHECK
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if (attr == NULL)
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return EINVAL;
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#endif
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attr->ptca_magic = _PT_CONDATTR_MAGIC;
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return 0;
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}
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int
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pthread_condattr_destroy(pthread_condattr_t *attr)
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{
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#ifdef ERRORCHECK
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if ((attr == NULL) ||
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(attr->ptca_magic != _PT_CONDATTR_MAGIC))
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return EINVAL;
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#endif
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attr->ptca_magic = _PT_CONDATTR_DEAD;
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return 0;
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}
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/* Utility routine to hang out for a while if threads haven't started yet. */
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static int
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pthread_cond_wait_nothread(pthread_t self, pthread_mutex_t *mutex,
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const struct timespec *abstime)
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{
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struct timeval now, tv, *tvp;
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int retval;
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if (abstime == NULL)
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tvp = NULL;
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else {
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tvp = &tv;
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gettimeofday(&now, NULL);
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TIMESPEC_TO_TIMEVAL(tvp, abstime);
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timersub(tvp, &now, tvp);
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}
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/*
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* The libpthread select() wrapper has cancellation tests, but
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* we need to have the mutex locked when testing for
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* cancellation and unlocked while we sleep. So, skip the
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* wrapper.
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*/
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pthread__testcancel(self);
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pthread_mutex_unlock(mutex);
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retval = _sys_select(0, NULL, NULL, NULL, tvp);
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pthread_mutex_lock(mutex);
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pthread__testcancel(self);
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if (retval == 0)
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return ETIMEDOUT;
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else
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return EINTR;
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}
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