149 lines
4.1 KiB
C
149 lines
4.1 KiB
C
/* Cancel requests associated with given file descriptor.
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Copyright (C) 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* We use an UGLY hack to prevent gcc from finding us cheating. The
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implementation of aio_cancel and aio_cancel64 are identical and so
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we want to avoid code duplication by using aliases. But gcc sees
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the different parameter lists and prints a warning. We define here
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a function so that aio_cancel64 has no prototype. */
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#define aio_cancel64 XXX
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#include <aio.h>
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/* And undo the hack. */
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#undef aio_cancel64
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#include <errno.h>
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#include "aio_misc.h"
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int
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aio_cancel (fildes, aiocbp)
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int fildes;
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struct aiocb *aiocbp;
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{
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struct requestlist *req = NULL;
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int result = AIO_ALLDONE;
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/* Request the mutex. */
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pthread_mutex_lock (&__aio_requests_mutex);
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/* We are asked to cancel a specific AIO request. */
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if (aiocbp != NULL)
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{
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/* If the AIO request is not for this descriptor it has no value
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to look for the request block. */
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if (aiocbp->aio_fildes == fildes)
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{
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struct requestlist *last = NULL;
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req = __aio_find_req_fd (fildes);
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while (req->aiocbp != (aiocb_union *) aiocbp)
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{
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last = req;
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req = req->next_prio;
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}
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/* Don't remove the entry if a thread is already working on it. */
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if (req->running == allocated)
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result = AIO_NOTCANCELED;
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else
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{
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/* We can remove the entry. */
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if (last != NULL)
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last->next_prio = req->next_prio;
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else
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if (req->next_prio == NULL)
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{
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if (req->last_fd != NULL)
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req->last_fd->next_fd = req->next_fd;
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if (req->next_fd != NULL)
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req->next_fd->last_fd = req->last_fd;
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}
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else
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{
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if (req->last_fd != NULL)
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req->last_fd->next_fd = req->next_prio;
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if (req->next_fd != NULL)
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req->next_fd->last_fd = req->next_prio;
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req->next_prio->last_fd = req->last_fd;
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req->next_prio->next_fd = req->next_fd;
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/* Mark this entry as runnable. */
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req->next_prio->running = yes;
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}
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result = AIO_CANCELED;
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}
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req->next_prio = NULL;
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}
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}
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else
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{
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/* Find the beginning of the list of all requests for this
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desriptor. */
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req = __aio_find_req_fd (fildes);
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/* If any request is worked on by a thread it must be the first.
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So either we can delete all requests or all but the first. */
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if (req != NULL)
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{
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if (req->running == allocated)
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{
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struct requestlist *old = req;
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req = req->next_prio;
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old->next_prio = NULL;
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result = AIO_NOTCANCELED;
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}
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else
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{
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/* Remove entry from the file descriptor list. */
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if (req->last_fd != NULL)
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req->last_fd->next_fd = req->next_fd;
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if (req->next_fd != NULL)
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req->next_fd->last_fd = req->last_fd;
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result = AIO_CANCELED;
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}
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}
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}
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/* Mark requests as canceled and send signal. */
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while (req != NULL)
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{
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struct requestlist *old = req;
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req->aiocbp->aiocb.__error_code = ECANCELED;
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req->aiocbp->aiocb.__return_value = -1;
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__aio_notify (req);
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req = req->next_prio;
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__aio_free_request (old);
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}
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/* Release the mutex. */
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pthread_mutex_unlock (&__aio_requests_mutex);
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return result;
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}
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weak_alias (aio_cancel, aio_cancel64)
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