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218/****************************************************************************
* fs/event/event_open.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 <sys/stat.h>
#include <stdarg.h>
#include <stdio.h>
#include <fcntl.h>
#include <nuttx/kmalloc.h>
#include <nuttx/event.h>
#include <nuttx/fs/fs.h>
#include "inode/inode.h"
#include "vfs/vfs.h"
#include "event/event.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxevent_open
*
* Description:
* This function establishes a connection between named event groups and a
* task. the task may reference the event group associated with name using
* the address returned by this call. The event group may be used in a
* subsequent calls to nxevent_wait(), or nxevent_post(). And the event
* group remains usable until the event group is closed by a successful
* call to nxevent_close().
*
* If a task makes multiple calls to event_open() with the same name, then
* the same event group address is returned.
*
* Input Parameters:
* event - Location to return the event group reference.
* name - event group name.
* oflags - event group creation options. This may either or both of the
* following bit settings.
* oflags = 0: Connect to the event group only if it already exists.
* oflags = O_CREAT: Connect to the event group if it exists, otherwise
* create the event group.
* oflags = O_CREAT|O_EXCL: Create a new event group unless
* already exists.
* Optional parameters. When the O_CREAT flag is specified, two optional
* parameters are expected:
* 1. mode_t mode, is required but not used in the present
* implementation.
* 2. unsigned events. The event group is created with an initial
* value of events.
*
* Returned Value:
* 0 (OK), or negated errno if unsuccessful.
*
* Assumptions:
*
****************************************************************************/
int nxevent_open(FAR nxevent_t **event, FAR const char *name,
int oflags, ...)
{
FAR struct inode *inode;
FAR struct nevent_inode_s *nevent;
struct inode_search_s desc;
char fullpath[MAX_EVENTPATH];
mode_t mode;
nxevent_mask_t events = 0;
int ret;
/* Get the full path to the */
snprintf(fullpath, MAX_EVENTPATH,
CONFIG_FS_NAMED_EVENTS_VFS_PATH "/%s", name);
/* Get the inode for this event group. This should succeed if the
* event group has already been created. In this case, inode_find()
* will have incremented the reference count on the inode.
*/
SETUP_SEARCH(&desc, fullpath, false);
ret = inode_find(&desc);
if (ret >= 0)
{
/* Something exists at this path. Get the search results */
inode = desc.node;
/* Verify that the inode is a event group */
if (!INODE_IS_NAMEDEVENT(inode))
{
ret = -ENXIO;
goto errout_with_inode;
}
/* It exists and is a event group. Check if the caller wanted to
* create a new event group with this name.
*/
if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
{
ret = -EEXIST;
goto errout_with_inode;
}
/* Return a reference to the event group, retaining the reference
* count on the inode.
*/
*event = &inode->u.i_nevent->ne_event;
}
else
{
va_list ap;
/* The event group does not exists. Were we asked to create it? */
if ((oflags & O_CREAT) == 0)
{
/* The event group does not exist and O_CREAT is not set */
ret = -ENOENT;
goto errout_with_search;
}
/* Create the event group. First we have to extract the additional
* parameters from the variable argument list.
* REVISIT: Mode parameter is not currently used.
*/
va_start(ap, oflags);
mode = va_arg(ap, mode_t) & ~getumask();
events = va_arg(ap, nxevent_mask_t);
va_end(ap);
/* Create an inode in the pseudo-filesystem at this path. The new
* inode will be created with a reference count of zero.
*/
inode_lock();
ret = inode_reserve(fullpath, mode, &inode);
inode_unlock();
if (ret < 0)
{
goto errout_with_search;
}
/* Allocate the event group structure (using the appropriate allocator
* for the group)
*/
nevent = group_malloc(NULL, sizeof(struct nevent_inode_s));
if (!nevent)
{
ret = -ENOMEM;
goto errout_with_inode;
}
/* Link to the inode */
inode->u.i_nevent = nevent;
nevent->ne_inode = inode;
/* Initialize the inode */
INODE_SET_NAMEDEVENT(inode);
atomic_fetch_add(&inode->i_crefs, 1);
/* Initialize the event groups */
nxevent_init(&nevent->ne_event, events);
/* Return a reference to the event groups */
*event = &nevent->ne_event;
}
RELEASE_SEARCH(&desc);
#ifdef CONFIG_FS_NOTIFY
notify_open(fullpath, oflags);
#endif
return OK;
errout_with_inode:
inode_release(inode);
errout_with_search:
RELEASE_SEARCH(&desc);
return ret;
}