diff options
Diffstat (limited to 'lib/libthr/thread/thr_cancel.c')
| -rw-r--r-- | lib/libthr/thread/thr_cancel.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_cancel.c b/lib/libthr/thread/thr_cancel.c new file mode 100644 index 0000000..1047eb2 --- /dev/null +++ b/lib/libthr/thread/thr_cancel.c @@ -0,0 +1,163 @@ +/* + * Copyright (c) 2005, David Xu <davidxu@freebsd.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + * + */ + +#include "namespace.h" +#include <pthread.h> +#include "un-namespace.h" + +#include "thr_private.h" + +__weak_reference(_pthread_cancel, pthread_cancel); +__weak_reference(_pthread_setcancelstate, pthread_setcancelstate); +__weak_reference(_pthread_setcanceltype, pthread_setcanceltype); +__weak_reference(_pthread_testcancel, pthread_testcancel); + +int +_pthread_cancel(pthread_t pthread) +{ + struct pthread *curthread = _get_curthread(); + int oldval, newval = 0; + int oldtype; + int ret; + + /* + * POSIX says _pthread_cancel should be async cancellation safe, + * so we temporarily disable async cancellation. + */ + _pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype); + if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) { + _pthread_setcanceltype(oldtype, NULL); + return (ret); + } + + do { + oldval = pthread->cancelflags; + if (oldval & THR_CANCEL_NEEDED) + break; + newval = oldval | THR_CANCEL_NEEDED; + } while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval)); + + if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval)) + _thr_send_sig(pthread, SIGCANCEL); + + _thr_ref_delete(curthread, pthread); + _pthread_setcanceltype(oldtype, NULL); + return (0); +} + +static inline void +testcancel(struct pthread *curthread) +{ + int newval; + + newval = curthread->cancelflags; + if (SHOULD_CANCEL(newval) && !THR_IN_CRITICAL(curthread)) + _pthread_exit(PTHREAD_CANCELED); +} + +int +_pthread_setcancelstate(int state, int *oldstate) +{ + struct pthread *curthread = _get_curthread(); + int oldval, ret; + + oldval = curthread->cancelflags; + if (oldstate != NULL) + *oldstate = ((oldval & THR_CANCEL_DISABLE) ? + PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE); + switch (state) { + case PTHREAD_CANCEL_DISABLE: + atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE); + ret = 0; + break; + case PTHREAD_CANCEL_ENABLE: + atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE); + testcancel(curthread); + ret = 0; + break; + default: + ret = EINVAL; + } + + return (ret); +} + +int +_pthread_setcanceltype(int type, int *oldtype) +{ + struct pthread *curthread = _get_curthread(); + int oldval, ret; + + oldval = curthread->cancelflags; + if (oldtype != NULL) + *oldtype = ((oldval & THR_CANCEL_AT_POINT) ? + PTHREAD_CANCEL_ASYNCHRONOUS : + PTHREAD_CANCEL_DEFERRED); + switch (type) { + case PTHREAD_CANCEL_ASYNCHRONOUS: + atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT); + testcancel(curthread); + ret = 0; + break; + case PTHREAD_CANCEL_DEFERRED: + atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT); + ret = 0; + break; + default: + ret = EINVAL; + } + + return (ret); +} + +void +_pthread_testcancel(void) +{ + testcancel(_get_curthread()); +} + +int +_thr_cancel_enter(struct pthread *curthread) +{ + int oldval; + + oldval = curthread->cancelflags; + if (!(oldval & THR_CANCEL_AT_POINT)) { + atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT); + testcancel(curthread); + } + return (oldval); +} + +void +_thr_cancel_leave(struct pthread *curthread, int previous) +{ + if (!(previous & THR_CANCEL_AT_POINT)) + atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT); +} |
