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Diffstat (limited to 'nuttx/sched/pthread_condwait.c')
-rw-r--r-- | nuttx/sched/pthread_condwait.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/nuttx/sched/pthread_condwait.c b/nuttx/sched/pthread_condwait.c new file mode 100644 index 000000000..bf0164d2d --- /dev/null +++ b/nuttx/sched/pthread_condwait.c @@ -0,0 +1,137 @@ +/**************************************************************************** + * sched/pthread_condwait.c + * + * Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * 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 <nuttx/config.h> + +#include <unistd.h> +#include <pthread.h> +#include <sched.h> +#include <errno.h> +#include <debug.h> + +#include "pthread_internal.h" + +/**************************************************************************** + * 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 = 0; + 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; +} + |