diff options
Diffstat (limited to 'rt/aio_cancel.c')
| -rw-r--r-- | rt/aio_cancel.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/rt/aio_cancel.c b/rt/aio_cancel.c new file mode 100644 index 0000000..f2d9389 --- /dev/null +++ b/rt/aio_cancel.c @@ -0,0 +1,172 @@ +/* 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) |