xref: /netbsd-src/lib/libpthread/pthread_specific.c (revision 76c7fc5f6b13ed0b1508e6b313e88e59977ed78e)
1 /*	$NetBSD: pthread_specific.c,v 1.26 2013/03/21 16:49:12 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 1.26 2013/03/21 16:49:12 christos Exp $");
34 
35 /* Functions and structures dealing with thread-specific data */
36 
37 #include "pthread.h"
38 #include "pthread_int.h"
39 #include "reentrant.h"
40 
41 #include <string.h>
42 #include <sys/lwpctl.h>
43 
44 #include "../libc/include/extern.h" /* for _sys_setcontext() */
45 
46 int	pthread_setcontext(const ucontext_t *);
47 
48 __strong_alias(__libc_thr_setspecific,pthread_setspecific)
49 __strong_alias(__libc_thr_getspecific,pthread_getspecific)
50 __strong_alias(__libc_thr_curcpu,pthread_curcpu_np)
51 
52 __strong_alias(setcontext,pthread_setcontext)
53 
54 int
55 pthread_setspecific(pthread_key_t key, const void *value)
56 {
57 	pthread_t self;
58 
59 	if (__predict_false(__uselibcstub))
60 		return __libc_thr_setspecific_stub(key, value);
61 
62 	self = pthread__self();
63 	/*
64 	 * We can't win here on constness. Having been given a
65 	 * "const void *", we can only assign it to other const void *,
66 	 * and return it from functions that are const void *, without
67 	 * generating a warning.
68 	 */
69 	return pthread__add_specific(self, key, value);
70 }
71 
72 void *
73 pthread_getspecific(pthread_key_t key)
74 {
75 	if (__predict_false(__uselibcstub))
76 		return __libc_thr_getspecific_stub(key);
77 
78 	return pthread__self()->pt_specific[key].pts_value;
79 }
80 
81 unsigned int
82 pthread_curcpu_np(void)
83 {
84 	if (__predict_false(__uselibcstub))
85 		return __libc_thr_curcpu_stub();
86 
87 	{
88 		const int curcpu = pthread__self()->pt_lwpctl->lc_curcpu;
89 
90 		pthread__assert(curcpu != LWPCTL_CPU_NONE);
91 		pthread__assert(curcpu != LWPCTL_CPU_EXITED);
92 		pthread__assert(curcpu >= 0);
93 		return curcpu;
94 	}
95 }
96 
97 /*
98  * Override setcontext so that pthread private pointer is preserved
99  */
100 int
101 pthread_setcontext(const ucontext_t *ucp)
102 {
103 #ifdef _UC_TLSBASE
104 	ucontext_t uc;
105 	/*
106 	 * Only copy and clear _UC_TLSBASE if it is set.
107 	 */
108 	if (ucp->uc_flags & _UC_TLSBASE) {
109 		uc = *ucp;
110 		uc.uc_flags &= ~_UC_TLSBASE;
111 		ucp = &uc;
112 	}
113 #endif /* _UC_TLSBASE */
114 	return _sys_setcontext(ucp);
115 }
116