138 lines
4.4 KiB
C
138 lines
4.4 KiB
C
/****************************************************************************
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* sched/pthread/pthread_condwait.c
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*
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* Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* 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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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <sched.h>
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#include <errno.h>
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#include <debug.h>
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#include "pthread/pthread.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Declarations
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****************************************************************************/
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/****************************************************************************
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* Global Variables
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: int pthread_cond_wait
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*
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* Description:
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* A thread can wait for a condition variable to be signalled or broadcast.
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*
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* Parameters:
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* None
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*
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* Return Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex)
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{
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int ret;
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sdbg("cond=0x%p mutex=0x%p\n", cond, mutex);
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/* Make sure that non-NULL references were provided. */
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if (!cond || !mutex)
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{
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ret = EINVAL;
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}
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/* Make sure that the caller holds the mutex */
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else if (mutex->pid != (int)getpid())
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{
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ret = EPERM;
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}
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else
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{
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/* Give up the mutex */
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sdbg("Give up mutex / take cond\n");
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sched_lock();
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mutex->pid = 0;
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ret = pthread_givesemaphore((sem_t*)&mutex->sem);
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/* Take the semaphore */
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ret |= pthread_takesemaphore((sem_t*)&cond->sem);
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sched_unlock();
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/* Reacquire the mutex */
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sdbg("Reacquire mutex...\n");
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ret |= pthread_takesemaphore((sem_t*)&mutex->sem);
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if (!ret)
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{
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mutex->pid = getpid();;
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}
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}
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sdbg("Returning %d\n", ret);
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return ret;
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}
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