134 lines
5.0 KiB
C
134 lines
5.0 KiB
C
/****************************************************************************
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* libs/libc/aio/aio_suspend.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sched.h>
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#include <signal.h>
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#include <aio.h>
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#include <assert.h>
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#include <errno.h>
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#ifdef CONFIG_FS_AIO
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: aio_suspend
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*
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* Description:
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* The aio_suspend() function suspends the calling thread until at least
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* one of the asynchronous I/O operations referenced by the 'list' argument
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* has completed, until a signal interrupts the function, or, if 'timeout'
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* is not NULL, until the time interval specified by 'timeout' has passed.
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* If any of the aiocb structures in the list correspond to completed
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* asynchronous I/O operations (that is, the error status for the
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* operation is not equal to EINPROGRESS) at the time of the call, the
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* function returns without suspending the calling thread.
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*
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* Each aiocb structure pointed to must have been used in initiating an
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* asynchronous I/O request via aio_read(), aio_write(), or lio_listio().
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* This array may contain NULL pointers, which are ignored. If this
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* array contains pointers that refer to aiocb structures that have not
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* been used in submitting asynchronous I/O, the effect is undefined.
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*
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* Input Parameters:
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* list - An array of pointers to asynchronous I/O control blocks.
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* nent - The number of elements in the array.
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* aiocbp - A pointer to an array
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* timeout - If not NULL, this parameter is pointer to a timespec
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* structure that determines a timeout on the operation. If
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* the time referred to timeout passes before any of the I/O
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* operations referenced by list are completed, then
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* aio_suspend() returns with an error.
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*
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* Returned Value:
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* If the aio_suspend() function returns after one or more asynchronous
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* I/O operations have completed, the function returns zero. Otherwise,
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* the function returns a value of -1 and sets errno to indicate the
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* error. The application may determine which asynchronous I/O completed
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* by scanning the associated error and return status using aio_error()
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* and aio_return(), respectively.
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*
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* The aio_suspend() function will fail if:
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*
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* EAGAIN - No asynchronous I/O indicated in the list referenced by
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* list completed in the time interval indicated by timeout.
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* EINTR - A signal interrupted the aio_suspend() function.
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*
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****************************************************************************/
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int aio_suspend(FAR const struct aiocb * const list[], int nent,
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FAR const struct timespec *timeout)
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{
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sigset_t set;
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int ret;
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int i;
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DEBUGASSERT(list);
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/* Lock the scheduler so that no I/O events can complete on the worker
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* thread until we set our wait set up. Pre-emption will, of course, be
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* re-enabled while we are waiting for the signal.
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*/
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sched_lock();
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/* Check each entry in the list. Break out of the loop if any entry
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* has completed.
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*/
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for (i = 0; i < nent; i++)
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{
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/* Check if the I/O has completed */
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if (list[i] && list[i]->aio_result != -EINPROGRESS)
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{
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/* Yes, return success */
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sched_unlock();
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return OK;
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}
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}
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/* Then wait for SIGPOLL. On success sigtimedwait() will return the
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* signal number that cause the error (SIGPOLL). It will set errno
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* appropriately for this function on errors.
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*
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* NOTE: If completion of the I/O causes other signals to be generated
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* first, then this will wake up and return EINTR instead of success.
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*/
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sigemptyset(&set);
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sigaddset(&set, SIGPOLL);
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ret = sigtimedwait(&set, NULL, timeout);
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sched_unlock();
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return ret >= 0 ? OK : ERROR;
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}
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#endif /* CONFIG_FS_AIO */
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