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/****************************************************************************
* libc/aio/aio_suspend.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 <signal.h>
#include <aio.h>
#include <assert.h>
#include <errno.h>
#ifndef CONFIG_LIBC_AIO
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: aio_suspend
*
* Description:
* The aio_suspend() function suspends the calling thread until at least
* one of the asynchronous I/O operations referenced by the 'list' argument
* has completed, until a signal interrupts the function, or, if 'timeout'
* is not NULL, until the time interval specified by 'timeout' has passed.
* If any of the aiocb structures in the list correspond to completed
* asynchronous I/O operations (that is, the error status for the
* operation is not equal to EINPROGRESS) at the time of the call, the
* function returns without suspending the calling thread.
*
* Each aiocb structure pointed to must have been used in initiating an
* asynchronous I/O request via aio_read(), aio_write(), or lio_listio().
* This array may contain NULL pointers, which are ignored. If this
* array contains pointers that refer to aiocb structures that have not
* been used in submitting asynchronous I/O, the effect is undefined.
*
* Input Parameters:
* list - An array of pointers to asynchronous I/O control blocks.
* nent - The number of elements in the array.
* aiocbp - A pointer to an array
* timeout - If not NULL, this parameter is pointer to a timespec
* structure that determines a timeout on the operation. If
* the time referred to timeout passes before any of the I/O
* operations referenced by list are completed, then
* aio_suspend() returns with an error.
*
* Returned Value:
* If the aio_suspend() function returns after one or more asynchronous
* I/O operations have completed, the function returns zero. Otherwise,
* the function returns a value of -1 and sets errno to indicate the
* error. The application may determine which asynchronous I/O completed
* by scanning the associated error and return status using aio_error()
* and aio_return(), respectively.
*
* The aio_suspend() function will fail if:
*
* EAGAIN - No asynchronous I/O indicated in the list referenced by
* list completed in the time interval indicated by timeout.
* EINTR - A signal interrupted the aio_suspend() function.
*
****************************************************************************/
int aio_suspend(FAR const struct aiocb *const list[], int nent,
FAR const struct timespec *timeout)
{
sigset_t set;
int ret;
int i;
DEBUGASSERT(aiocbp);
/* Lock the scheduler so that no I/O events can complete on the worker
* thread until we set our wait set up. Pre-emption will, of course, be
* re-enabled while we are waiting for the signal.
*/
sched_lock();
/* Check each entry in the list. Break out of the loop if any entry
* has completed.
*/
for (i = 0; i < nent; i++)
{
/* Check if the I/O has completed */
if (list[i] && list[i]->aio_result != -EINPROGRESS)
{
/* Yes, return success */
sched_unlock();
return OK;
}
}
/* Then wait for SIGPOLL. On success sigtimedwait() will return the
* signal number that cause the error (SIGPOLL). It will set errno
* appropriately for this function on errors.
*
* NOTE: If completion of the I/O causes other signals to be generated
* first, then this will wake up and return EINTR instead of success.
*/
sigemptyset(&set);
sigaddset(&set, SIGPOLL);
ret = sigtimedwait(&set, NULL, &timeout)
sched_unlock();
return ret >= 0 ? OK : ERROR;
}
#endif /* CONFIG_LIBC_AIO */
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