xref: /freebsd/lib/libc/gen/_once_stub.c (revision 8271d9b99a3b98c662ee9a6257a144284b7e1728)
1*8271d9b9SKonstantin Belousov /*-
2*8271d9b9SKonstantin Belousov  * SPDX-License-Identifier: BSD-2-Clause
3*8271d9b9SKonstantin Belousov  *
4*8271d9b9SKonstantin Belousov  * Copyright (c) 2009 Hudson River Trading LLC
5*8271d9b9SKonstantin Belousov  * Written by: John H. Baldwin <jhb@FreeBSD.org>
6*8271d9b9SKonstantin Belousov  * All rights reserved.
7*8271d9b9SKonstantin Belousov  *
8*8271d9b9SKonstantin Belousov  * Redistribution and use in source and binary forms, with or without
9*8271d9b9SKonstantin Belousov  * modification, are permitted provided that the following conditions
10*8271d9b9SKonstantin Belousov  * are met:
11*8271d9b9SKonstantin Belousov  * 1. Redistributions of source code must retain the above copyright
12*8271d9b9SKonstantin Belousov  *    notice, this list of conditions and the following disclaimer.
13*8271d9b9SKonstantin Belousov  * 2. Redistributions in binary form must reproduce the above copyright
14*8271d9b9SKonstantin Belousov  *    notice, this list of conditions and the following disclaimer in the
15*8271d9b9SKonstantin Belousov  *    documentation and/or other materials provided with the distribution.
16*8271d9b9SKonstantin Belousov  *
17*8271d9b9SKonstantin Belousov  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18*8271d9b9SKonstantin Belousov  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19*8271d9b9SKonstantin Belousov  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20*8271d9b9SKonstantin Belousov  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21*8271d9b9SKonstantin Belousov  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22*8271d9b9SKonstantin Belousov  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23*8271d9b9SKonstantin Belousov  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24*8271d9b9SKonstantin Belousov  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25*8271d9b9SKonstantin Belousov  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26*8271d9b9SKonstantin Belousov  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27*8271d9b9SKonstantin Belousov  * SUCH DAMAGE.
28*8271d9b9SKonstantin Belousov  */
29*8271d9b9SKonstantin Belousov 
30*8271d9b9SKonstantin Belousov #include "namespace.h"
31*8271d9b9SKonstantin Belousov #include <pthread.h>
32*8271d9b9SKonstantin Belousov #include "un-namespace.h"
33*8271d9b9SKonstantin Belousov #include "libc_private.h"
34*8271d9b9SKonstantin Belousov 
35*8271d9b9SKonstantin Belousov /* This implements pthread_once() for the single-threaded case. */
36*8271d9b9SKonstantin Belousov static int
_libc_once(pthread_once_t * once_control,void (* init_routine)(void))37*8271d9b9SKonstantin Belousov _libc_once(pthread_once_t *once_control, void (*init_routine)(void))
38*8271d9b9SKonstantin Belousov {
39*8271d9b9SKonstantin Belousov 
40*8271d9b9SKonstantin Belousov 	if (once_control->state == PTHREAD_DONE_INIT)
41*8271d9b9SKonstantin Belousov 		return (0);
42*8271d9b9SKonstantin Belousov 	init_routine();
43*8271d9b9SKonstantin Belousov 	once_control->state = PTHREAD_DONE_INIT;
44*8271d9b9SKonstantin Belousov 	return (0);
45*8271d9b9SKonstantin Belousov }
46*8271d9b9SKonstantin Belousov 
47*8271d9b9SKonstantin Belousov /*
48*8271d9b9SKonstantin Belousov  * This is the internal interface provided to libc.  It will use
49*8271d9b9SKonstantin Belousov  * pthread_once() from the threading library in a multi-threaded
50*8271d9b9SKonstantin Belousov  * process and _libc_once() for a single-threaded library.  Because
51*8271d9b9SKonstantin Belousov  * _libc_once() uses the same ABI for the values in the pthread_once_t
52*8271d9b9SKonstantin Belousov  * structure as the threading library, it is safe for a process to
53*8271d9b9SKonstantin Belousov  * switch from _libc_once() to pthread_once() when threading is
54*8271d9b9SKonstantin Belousov  * enabled.
55*8271d9b9SKonstantin Belousov  */
56*8271d9b9SKonstantin Belousov int
_once(pthread_once_t * once_control,void (* init_routine)(void))57*8271d9b9SKonstantin Belousov _once(pthread_once_t *once_control, void (*init_routine)(void))
58*8271d9b9SKonstantin Belousov {
59*8271d9b9SKonstantin Belousov 
60*8271d9b9SKonstantin Belousov 	if (__isthreaded)
61*8271d9b9SKonstantin Belousov 		return (_pthread_once(once_control, init_routine));
62*8271d9b9SKonstantin Belousov 	return (_libc_once(once_control, init_routine));
63*8271d9b9SKonstantin Belousov }
64