/**************************************************************************** * sched/pthread/pthread_condwait.c * * Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "pthread/pthread.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Global Variables ****************************************************************************/ /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: int pthread_cond_wait * * Description: * A thread can wait for a condition variable to be signalled or broadcast. * * Parameters: * None * * Return Value: * None * * Assumptions: * ****************************************************************************/ int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex) { int ret; sdbg("cond=0x%p mutex=0x%p\n", cond, mutex); /* Make sure that non-NULL references were provided. */ if (!cond || !mutex) { ret = EINVAL; } /* Make sure that the caller holds the mutex */ else if (mutex->pid != (int)getpid()) { ret = EPERM; } else { /* Give up the mutex */ sdbg("Give up mutex / take cond\n"); sched_lock(); mutex->pid = -1; ret = pthread_givesemaphore((sem_t*)&mutex->sem); /* Take the semaphore */ ret |= pthread_takesemaphore((sem_t*)&cond->sem); sched_unlock(); /* Reacquire the mutex */ sdbg("Reacquire mutex...\n"); ret |= pthread_takesemaphore((sem_t*)&mutex->sem); if (!ret) { mutex->pid = getpid(); } } sdbg("Returning %d\n", ret); return ret; }