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glibc/rt/aio_cancel.c
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/* Cancel requests associated with given file descriptor. | |
Copyright (C) 1997, 1998, 2000 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 <assert.h> | |
#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); | |
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; | |
} | |
weak_alias (aio_cancel, aio_cancel64) |