xref: /netbsd-src/lib/libpthread/pthread_specific.c (revision a536ee5124e62c9a0051a252f7833dc8f50f44c9)
1 /*	$NetBSD: pthread_specific.c,v 1.24 2012/11/21 19:19:24 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 2001, 2007 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.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: pthread_specific.c,v 1.24 2012/11/21 19:19:24 christos Exp $");
34 
35 /* Functions and structures dealing with thread-specific data */
36 
37 #include "pthread.h"
38 #include "pthread_int.h"
39 
40 #include <string.h>
41 #include <sys/lwpctl.h>
42 
43 #include "../libc/include/extern.h" /* for _sys_setcontext() */
44 
45 int	pthread_setcontext(const ucontext_t *);
46 
47 __strong_alias(__libc_thr_setspecific,pthread_setspecific)
48 __strong_alias(__libc_thr_getspecific,pthread_getspecific)
49 __strong_alias(__libc_thr_curcpu,pthread_curcpu_np)
50 
51 __strong_alias(setcontext,pthread_setcontext)
52 
53 int
54 pthread_setspecific(pthread_key_t key, const void *value)
55 {
56 	pthread_t self;
57 
58 	self = pthread__self();
59 	/*
60 	 * We can't win here on constness. Having been given a
61 	 * "const void *", we can only assign it to other const void *,
62 	 * and return it from functions that are const void *, without
63 	 * generating a warning.
64 	 */
65 	return pthread__add_specific(self, key, value);
66 }
67 
68 void *
69 pthread_getspecific(pthread_key_t key)
70 {
71 
72 	return pthread__self()->pt_specific[key].pts_value;
73 }
74 
75 unsigned int
76 pthread_curcpu_np(void)
77 {
78 
79 	return pthread__self()->pt_lwpctl->lc_curcpu;
80 }
81 
82 /*
83  * Override setcontext so that pthread private pointer is preserved
84  */
85 int
86 pthread_setcontext(const ucontext_t *ucp)
87 {
88 #ifdef _UC_TLSBASE
89 	ucontext_t uc;
90 	/*
91 	 * Only copy and clear _UC_TLSBASE if it is set.
92 	 */
93 	if (ucp->uc_flags & _UC_TLSBASE) {
94 		uc = *ucp;
95 		uc.uc_flags &= ~_UC_TLSBASE;
96 		ucp = &uc;
97 	}
98 #endif /* _UC_TLSBASE */
99 	return _sys_setcontext(ucp);
100 }
101