1 /* $NetBSD: pthread_once.c,v 1.4 2022/02/12 14:59:32 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2001, 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nathan J. Williams, and by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 #include <sys/cdefs.h>
40 __RCSID("$NetBSD: pthread_once.c,v 1.4 2022/02/12 14:59:32 riastradh Exp $");
41
42 /* Need to use libc-private names for atomic operations. */
43 #include "../../common/lib/libc/atomic/atomic_op_namespace.h"
44
45 #include "pthread.h"
46 #include "pthread_int.h"
47 #include "reentrant.h"
48
49 static void
once_cleanup(void * closure)50 once_cleanup(void *closure)
51 {
52
53 pthread_mutex_unlock((pthread_mutex_t *)closure);
54 }
55
56 int
pthread_once(pthread_once_t * once_control,void (* routine)(void))57 pthread_once(pthread_once_t *once_control, void (*routine)(void))
58 {
59 if (__predict_false(__uselibcstub))
60 return __libc_thr_once_stub(once_control, routine);
61
62 if (once_control->pto_done == 0) {
63 pthread_mutex_lock(&once_control->pto_mutex);
64 pthread_cleanup_push(&once_cleanup, &once_control->pto_mutex);
65 if (once_control->pto_done == 0) {
66 routine();
67 once_control->pto_done = 1;
68 }
69 pthread_cleanup_pop(1);
70 }
71
72 return 0;
73 }
74
75 __strong_alias(__libc_thr_once,pthread_once)
76