/**************************************************************************** * sched/pthread/pthread_condwait.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include "pthread/pthread.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: int pthread_cond_wait * * Description: * A thread can wait for a condition variable to be signalled or broadcast. * * Input Parameters: * None * * Returned Value: * None * * Assumptions: * ****************************************************************************/ int pthread_cond_wait(FAR pthread_cond_t *cond, FAR pthread_mutex_t *mutex) { int status; int ret; sinfo("cond=%p mutex=%p\n", cond, mutex); /* pthread_cond_wait() is a cancellation point */ enter_cancellation_point(); /* Make sure that non-NULL references were provided. */ if (cond == NULL || mutex == NULL) { ret = EINVAL; } /* Make sure that the caller holds the mutex */ else if (mutex->pid != gettid()) { ret = EPERM; } else { #ifndef CONFIG_PTHREAD_MUTEX_UNSAFE uint8_t mflags; #endif #ifdef CONFIG_PTHREAD_MUTEX_TYPES uint8_t type; int16_t nlocks; #endif /* Give up the mutex */ sinfo("Give up mutex / take cond\n"); sched_lock(); mutex->pid = INVALID_PROCESS_ID; #ifndef CONFIG_PTHREAD_MUTEX_UNSAFE mflags = mutex->flags; #endif #ifdef CONFIG_PTHREAD_MUTEX_TYPES type = mutex->type; nlocks = mutex->nlocks; #endif ret = pthread_mutex_give(mutex); /* Take the semaphore. This may be awakened only be a signal (EINTR) * or if the thread is canceled (ECANCELED) */ status = pthread_sem_take(&cond->sem, NULL, false); if (ret == OK) { /* Report the first failure that occurs */ ret = status; } sched_unlock(); /* Reacquire the mutex. * * When cancellation points are enabled, we need to hold the mutex * when the pthread is canceled and cleanup handlers, if any, are * entered. */ sinfo("Reacquire mutex...\n"); status = pthread_mutex_take(mutex, NULL, false); if (ret == OK) { /* Report the first failure that occurs */ ret = status; } /* Did we get the mutex? */ if (status == OK) { /* Yes.. Then initialize it properly */ mutex->pid = gettid(); #ifndef CONFIG_PTHREAD_MUTEX_UNSAFE mutex->flags = mflags; #endif #ifdef CONFIG_PTHREAD_MUTEX_TYPES mutex->type = type; mutex->nlocks = nlocks; #endif } } leave_cancellation_point(); sinfo("Returning %d\n", ret); return ret; }