b72a7ab50b
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@404 42af7a65-404d-4744-a932-0658087f49c3
138 lines
4.0 KiB
C
138 lines
4.0 KiB
C
/************************************************************
|
|
* pthread_mutextrylock.c
|
|
*
|
|
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
|
*
|
|
* 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 Gregory Nutt 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 <sys/types.h>
|
|
#include <unistd.h>
|
|
#include <pthread.h>
|
|
#include <semaphore.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
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Function: pthread_mutex_trylock
|
|
*
|
|
* Description:
|
|
* Attempt to lock a mutex
|
|
*
|
|
* Parameters:
|
|
* None
|
|
*
|
|
* Return Value:
|
|
* None
|
|
*
|
|
* Assumptions:
|
|
*
|
|
************************************************************/
|
|
|
|
int pthread_mutex_trylock(pthread_mutex_t *mutex)
|
|
{
|
|
int ret = OK;
|
|
|
|
sdbg("mutex=0x%p\n", mutex);
|
|
|
|
if (!mutex)
|
|
{
|
|
ret = EINVAL;
|
|
}
|
|
else
|
|
{
|
|
/* Make sure the semaphore is stable while we make the following
|
|
* checks. This all needs to be one atomic action.
|
|
*/
|
|
|
|
sched_lock();
|
|
|
|
/* Try to get the semaphore. */
|
|
|
|
if (sem_trywait((sem_t*)&mutex->sem) == OK)
|
|
{
|
|
/* If we succussfully obtained the semaphore, then indicate
|
|
* that we own it.
|
|
*/
|
|
|
|
mutex->pid = (int)getpid();
|
|
}
|
|
|
|
/* Was it not available? */
|
|
|
|
else if (*get_errno_ptr() == EAGAIN)
|
|
{
|
|
ret = EBUSY;
|
|
}
|
|
else
|
|
{
|
|
ret = EINVAL;
|
|
}
|
|
|
|
sched_unlock();
|
|
}
|
|
|
|
sdbg("Returning %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
|
|
|