nuttx/drivers/ipcc/ipcc_unlink.c

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/****************************************************************************
* drivers/ipcc/ipcc_unlink.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 <nuttx/config.h>
#include <nuttx/ipcc.h>
#include <nuttx/kmalloc.h>
#include <nuttx/semaphore.h>
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <sys/types.h>
#include "ipcc_priv.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ipcc_unlink
*
* Description:
* Action to take upon file unlinking. Function will free resources if
* noone is using the driver when unlinking occured. If driver is still
* in use, it will be marked as unlinked and resource freeing will take
* place in ipcc_close() function instead, once last reference is closed.
*
* Input Parameters:
* inode - driver inode that is being unlinked
*
* Returned Value:
* OK on successfull close, or negated errno on failure.
*
* Assumptions/Limitations:
*
****************************************************************************/
int ipcc_unlink(FAR struct inode *inode)
{
FAR struct ipcc_driver_s *priv;
int ret;
/* Get our private data structure */
DEBUGASSERT(inode);
priv = inode->i_private;
/* Get exclusive access to the IPCC driver state structure */
if ((ret = nxsem_wait(&priv->exclsem)) < 0)
{
return ret;
}
/* Is anyone still using the driver? */
if (priv->crefs <= 0)
{
/* No, we are free to free resources */
ipcc_cleanup(priv);
return OK;
}
/* Yes, someone is still using the driver, just mark file
* as unlinked and free resources in ipcc_close() once last
* reference is closed
*/
priv->unlinked = true;
nxsem_post(&priv->exclsem);
return OK;
}