diff options
Diffstat (limited to 'sysdeps/pthread/aio_cancel.c')
| -rw-r--r-- | sysdeps/pthread/aio_cancel.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/sysdeps/pthread/aio_cancel.c b/sysdeps/pthread/aio_cancel.c new file mode 100644 index 0000000..c1cfea5 --- /dev/null +++ b/sysdeps/pthread/aio_cancel.c @@ -0,0 +1,142 @@ +/* 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) |