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/* Cancel requests associated with given file descriptor.
Copyright (C) 1997, 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* 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. */
#define aio_cancel64 XXX
#include <aio.h>
/* And undo the hack. */
#undef aio_cancel64
#include <errno.h>
#include "aio_misc.h"
int
aio_cancel (fildes, aiocbp)
int fildes;
struct aiocb *aiocbp;
{
struct requestlist *req = NULL;
int result = AIO_ALLDONE;
/* 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)
{
struct requestlist *last = NULL;
req = __aio_find_req_fd (fildes);
while (req->aiocbp != (aiocb_union *) aiocbp)
{
last = req;
req = req->next_prio;
}
/* Don't remove the entry if a thread is already working on it. */
if (req->running == allocated)
result = AIO_NOTCANCELED;
else
{
/* We can remove the entry. */
if (last != NULL)
last->next_prio = req->next_prio;
else
if (req->next_prio == NULL)
{
if (req->last_fd != NULL)
req->last_fd->next_fd = req->next_fd;
if (req->next_fd != NULL)
req->next_fd->last_fd = req->last_fd;
}
else
{
if (req->last_fd != NULL)
req->last_fd->next_fd = req->next_prio;
if (req->next_fd != NULL)
req->next_fd->last_fd = req->next_prio;
req->next_prio->last_fd = req->last_fd;
req->next_prio->next_fd = req->next_fd;
/* Mark this entry as runnable. */
req->next_prio->running = yes;
}
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;
}
else
{
/* Remove entry from the file descriptor list. */
if (req->last_fd != NULL)
req->last_fd->next_fd = req->next_fd;
if (req->next_fd != NULL)
req->next_fd->last_fd = req->last_fd;
result = AIO_CANCELED;
}
}
}
/* Mark requests as canceled and send signal. */
while (req != NULL)
{
struct requestlist *old = req;
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;
}
weak_alias (aio_cancel, aio_cancel64)
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