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/* Cancel requests associated with given file descriptor.
Copyright (C) 1997 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 <pthread.h>
#include "aio_misc.h"
/* Argh, so far there is no ECANCELED. */
#define ECANCELED 125
int
aio_cancel (fildes, aiocbp)
int fildes;
struct aiocb *aiocbp;
{
struct aiocb *firstp;
int result = AIO_ALLDONE;
/* Request the semaphore. */
sem_wait (&__aio_requests_sema);
/* Search for the list of requests associated with the given file
descriptor. */
for (firstp = (struct aiocb *) __aio_requests; firstp != NULL;
firstp = firstp->__next_fd)
if (firstp->aio_fildes == fildes)
break;
/* If the file descriptor is not found all work seems to done
already. Otherwise try to cancel the request(s). */
if (firstp != NULL)
{
if (aiocbp != NULL)
{
/* Locate the entry corresponding to the AIOCBP parameter. */
if (aiocbp == firstp)
/* The requests is currently handled, therefore don't
cancel it and signal this to the user. */
result = AIO_NOTCANCELED;
else
{
while (firstp->__next_prio != NULL
&& aiocbp != firstp->__next_prio)
firstp = firstp->__next_prio;
if (firstp->__next_prio != NULL)
{
/* The request the user wants to cancel is in the
queue. Simply remove it. */
firstp->__next_prio = aiocbp->__next_prio;
/* Mark as canceled. */
aiocbp->__error_code = ECANCELED;
aiocbp->__return_value = -1;
/* Send the signal to notify about canceled
processing of the request. */
if (aiocbp->aio_sigevent.sigev_notify == SIGEV_THREAD)
{
/* We have to start a thread. */
pthread_t tid;
pthread_attr_t attr, *pattr;
pattr = (pthread_attr_t *)
aiocbp->aio_sigevent.sigev_notify_attributes;
if (pattr == NULL)
{
pthread_attr_init (&attr);
pthread_attr_setdetachstate (&attr,
PTHREAD_CREATE_DETACHED);
pattr = &attr;
}
pthread_create (&tid, pattr,
(void *(*) (void *))
aiocbp->aio_sigevent.sigev_notify_function,
aiocbp->aio_sigevent.sigev_value.sival_ptr);
}
else if (aiocbp->aio_sigevent.sigev_notify == SIGEV_SIGNAL)
/* We have to send a signal. */
__aio_sigqueue (aiocbp->aio_sigevent.sigev_signo,
aiocbp->aio_sigevent.sigev_value);
result = AIO_CANCELED;
}
}
}
else
{
/* First dequeue all waiting requests. */
aiocbp = firstp;
while ((firstp = firstp->__next_prio) != NULL)
{
firstp->__error_code = ECANCELED;
firstp->__return_value = -1;
/* Send the signal to notify about canceled processing
of the request. */
if (firstp->aio_sigevent.sigev_notify == SIGEV_THREAD)
{
/* We have to start a thread. */
pthread_t tid;
pthread_attr_t attr, *pattr;
pattr = (pthread_attr_t *)
aiocbp->aio_sigevent.sigev_notify_attributes;
if (pattr == NULL)
{
pthread_attr_init (&attr);
pthread_attr_setdetachstate (&attr,
PTHREAD_CREATE_DETACHED);
pattr = &attr;
}
pthread_create (&tid, pattr,
(void *(*) (void *))
firstp->aio_sigevent.sigev_notify_function,
firstp->aio_sigevent.sigev_value.sival_ptr);
}
else if (firstp->aio_sigevent.sigev_notify == SIGEV_SIGNAL)
/* We have to send a signal. */
__aio_sigqueue (firstp->aio_sigevent.sigev_signo,
firstp->aio_sigevent.sigev_value);
}
/* We have to signal that not all requests could be canceled
since the first requests is currently processed. */
result = AIO_NOTCANCELED;
aiocbp->__next_prio = NULL;
}
}
/* Release the semaphore. */
sem_post (&__aio_requests_sema);
return result;
}
weak_alias (aio_cancel, aio_cancel64)
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