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/****************************************************************************
* libc/aio/aio_cancel.c
*
* Copyright (C) 2014 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 <aio.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/wqueue.h>
#include "aio/aio.h"
#ifdef CONFIG_LIBC_AIO
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: aio_read
*
* Description:
* The aio_cancel() function attempts to cancel one or more asynchronous
* I/O requests currently outstanding against file descriptor 'fildes'.
* The aiocbp argument points to the asynchronous I/O control block for
* a particular request to be cancelled..
*
* Normal asynchronous notification will occur for asynchronous I/O
* operations that are successfully cancelled. If there are requests that
* cannot be cancelled, then the normal asynchronous completion process
* will take place for those requests when they are completed.
*
* For requested operations that are successfully cancelled, the associated
* error status will be set to ECANCELED and the return status will be -1.
* For requested operations that are not successfully cancelled, the aiocbp
* will not be modified by aio_cancel().
*
* Input Parameters:
* fildes - Not used in this implmentation
* aiocbp - Points to the asynchronous I/O control block for a particular
* request to be cancelled.
*
* Returned Value:
* The aio_cancel() function will return the value AIO_CANCELED if the
* requested operation(s) were cancelled. The value AIO_NOTCANCELED will
* be returned if at least one of the requested operation(s) cannot be
* cancelled because it is in progress. In this case, the state of the
* other operations, if any, referenced in the call to aio_cancel() is
* not indicated by the return value of aio_cancel(). The application
* may determine the state of affairs for these operations by using
* aio_error(). The value AIO_ALLDONE is returned if all of the
* operations have already completed. Otherwise, the function will return
* -1 and set errno to indicate the error.
*
* POSIX Compliance
* By standard, this function support the value of NULL for aiocbp. If
* aiocbp is NULL, then all outstanding cancelable asynchronous I/O
* requests against fildes will be cancelled. In this implementation,
* nothing is done if aiocbp is NULL and the fildes parameter is always
* ignored. ENOSYS will be returned.
*
****************************************************************************/
int aio_cancel(int fildes, FAR struct aiocb *aiocbp)
{
int status;
int ret;
/* Ignore NULL AIO control blocks (see "POSIX Compliance" above) */
if (aiocbp)
{
set_errno(ENOSYS);
return ERROR;
}
/* Lock the scheduler so that no I/O events can complete on the worker
* thread until we set complete this operation.
*/
sched_lock();
/* Check if the I/O has completed */
if (aiocbp->aio_result == -EINPROGRESS)
{
/* No ... attempt to cancel the I/O. There are two possibilities: (1)
* the work has already been started and is no longer queued, or (2)
* the work has not been started and is still in the work queue. Only
* the second case can be cancelled. work_cancel() will return
* -ENOENT in the first case.
*/
status = work_cancel(AIO_QUEUE, &aiocbp->aio_work);
ret = status >= 0 ? AIO_CANCELED : AIO_NOTCANCELED;
}
else
{
/* The I/O has already completed */
ret = AIO_ALLDONE;
}
sched_unlock();
return ret;
}
#endif /* CONFIG_LIBC_AIO */
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