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/* Cancel requests associated with given file descriptor.
Copyright (C) 1997-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* We use an UGLY hack to prevent gcc from finding us cheating. The
implementation of aio_cancel and aio_cancel64 are identical and so
we want to avoid code duplication by using aliases. But gcc sees
the different parameter lists and prints a warning. We define here
a function so that aio_cancel64 has no prototype. */
#ifndef aio_cancel
#define aio_cancel64 XXX
#include <aio.h>
/* And undo the hack. */
#undef aio_cancel64
#endif
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <aio_misc.h>
int
aio_cancel (int fildes, struct aiocb *aiocbp)
{
struct requestlist *req = NULL;
int result = AIO_ALLDONE;
/* If fildes is invalid, error. */
if (fcntl (fildes, F_GETFL) < 0)
{
__set_errno (EBADF);
return -1;
}
/* Request the mutex. */
pthread_mutex_lock (&__aio_requests_mutex);
/* We are asked to cancel a specific AIO request. */
if (aiocbp != NULL)
{
/* If the AIO request is not for this descriptor it has no value
to look for the request block. */
if (aiocbp->aio_fildes != fildes)
{
pthread_mutex_unlock (&__aio_requests_mutex);
__set_errno (EINVAL);
return -1;
}
else if (aiocbp->__error_code == EINPROGRESS)
{
struct requestlist *last = NULL;
req = __aio_find_req_fd (fildes);
if (req == NULL)
{
not_found:
pthread_mutex_unlock (&__aio_requests_mutex);
__set_errno (EINVAL);
return -1;
}
while (req->aiocbp != (aiocb_union *) aiocbp)
{
last = req;
req = req->next_prio;
if (req == NULL)
goto not_found;
}
/* Don't remove the entry if a thread is already working on it. */
if (req->running == allocated)
{
result = AIO_NOTCANCELED;
req = NULL;
}
else
{
/* We can remove the entry. */
__aio_remove_request (last, req, 0);
result = AIO_CANCELED;
req->next_prio = NULL;
}
}
}
else
{
/* Find the beginning of the list of all requests for this
desriptor. */
req = __aio_find_req_fd (fildes);
/* If any request is worked on by a thread it must be the first.
So either we can delete all requests or all but the first. */
if (req != NULL)
{
if (req->running == allocated)
{
struct requestlist *old = req;
req = req->next_prio;
old->next_prio = NULL;
result = AIO_NOTCANCELED;
if (req != NULL)
__aio_remove_request (old, req, 1);
}
else
{
result = AIO_CANCELED;
/* We can remove the entry. */
__aio_remove_request (NULL, req, 1);
}
}
}
/* Mark requests as canceled and send signal. */
while (req != NULL)
{
struct requestlist *old = req;
assert (req->running == yes || req->running == queued);
req->aiocbp->aiocb.__error_code = ECANCELED;
req->aiocbp->aiocb.__return_value = -1;
__aio_notify (req);
req = req->next_prio;
__aio_free_request (old);
}
/* Release the mutex. */
pthread_mutex_unlock (&__aio_requests_mutex);
return result;
}
#ifndef aio_cancel
weak_alias (aio_cancel, aio_cancel64)
#endif
|
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