2 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 #include "namespace.h"
32 #include "un-namespace.h"
34 #include "thr_private.h"
36 __weak_reference(_pthread_once, pthread_once);
38 #define ONCE_NEVER_DONE PTHREAD_NEEDS_INIT
39 #define ONCE_DONE PTHREAD_DONE_INIT
40 #define ONCE_IN_PROGRESS 0x02
41 #define ONCE_WAIT 0x03
45 * The pthread_once() function is not a cancellation point. However,
46 * if init_routine is a cancellation point and is canceled, the effect
47 * on once_control shall be as if pthread_once() was never called.
51 once_cancel_handler(void *arg)
53 pthread_once_t *once_control = arg;
55 if (atomic_cmpset_rel_int(&once_control->state, ONCE_IN_PROGRESS, ONCE_NEVER_DONE))
57 atomic_store_rel_int(&once_control->state, ONCE_NEVER_DONE);
58 _thr_umtx_wake(&once_control->state, INT_MAX, 0);
62 _pthread_once(pthread_once_t *once_control, void (*init_routine) (void))
64 struct pthread *curthread;
70 state = once_control->state;
71 if (state == ONCE_DONE)
73 if (state == ONCE_NEVER_DONE) {
74 if (atomic_cmpset_acq_int(&once_control->state, state, ONCE_IN_PROGRESS))
76 } else if (state == ONCE_IN_PROGRESS) {
77 if (atomic_cmpset_acq_int(&once_control->state, state, ONCE_WAIT))
78 _thr_umtx_wait_uint(&once_control->state, ONCE_WAIT, NULL, 0);
79 } else if (state == ONCE_WAIT) {
80 _thr_umtx_wait_uint(&once_control->state, state, NULL, 0);
85 curthread = _get_curthread();
86 THR_CLEANUP_PUSH(curthread, once_cancel_handler, once_control);
88 THR_CLEANUP_POP(curthread, 0);
89 if (atomic_cmpset_rel_int(&once_control->state, ONCE_IN_PROGRESS, ONCE_DONE))
91 atomic_store_rel_int(&once_control->state, ONCE_DONE);
92 _thr_umtx_wake(&once_control->state, INT_MAX, 0);