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      1 /*	$NetBSD: pthread_specific.c,v 1.28 2022/04/10 10:38:33 riastradh 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 1.28 2022/04/10 10:38:33 riastradh Exp $");
     34 
     35 /* Need to use libc-private names for atomic operations. */
     36 #include "../../common/lib/libc/atomic/atomic_op_namespace.h"
     37 
     38 /* Functions and structures dealing with thread-specific data */
     39 
     40 #include "pthread.h"
     41 #include "pthread_int.h"
     42 #include "reentrant.h"
     43 
     44 #include <string.h>
     45 #include <sys/lwpctl.h>
     46 
     47 #include "../libc/include/extern.h" /* for _sys_setcontext() */
     48 
     49 int	pthread_setcontext(const ucontext_t *);
     50 
     51 __strong_alias(__libc_thr_setspecific,pthread_setspecific)
     52 __strong_alias(__libc_thr_getspecific,pthread_getspecific)
     53 __strong_alias(__libc_thr_curcpu,pthread_curcpu_np)
     54 
     55 __strong_alias(setcontext,pthread_setcontext)
     56 
     57 int
     58 pthread_setspecific(pthread_key_t key, const void *value)
     59 {
     60 	pthread_t self;
     61 
     62 	if (__predict_false(__uselibcstub))
     63 		return __libc_thr_setspecific_stub(key, value);
     64 
     65 	self = pthread__self();
     66 	/*
     67 	 * We can't win here on constness. Having been given a
     68 	 * "const void *", we can only assign it to other const void *,
     69 	 * and return it from functions that are const void *, without
     70 	 * generating a warning.
     71 	 */
     72 	return pthread__add_specific(self, key, value);
     73 }
     74 
     75 void *
     76 pthread_getspecific(pthread_key_t key)
     77 {
     78 	if (__predict_false(__uselibcstub))
     79 		return __libc_thr_getspecific_stub(key);
     80 
     81 	return pthread__self()->pt_specific[key].pts_value;
     82 }
     83 
     84 unsigned int
     85 pthread_curcpu_np(void)
     86 {
     87 	if (__predict_false(__uselibcstub))
     88 		return __libc_thr_curcpu_stub();
     89 
     90 	{
     91 		const int curcpu = pthread__self()->pt_lwpctl->lc_curcpu;
     92 
     93 		pthread__assert(curcpu != LWPCTL_CPU_NONE);
     94 		pthread__assert(curcpu != LWPCTL_CPU_EXITED);
     95 		pthread__assert(curcpu >= 0);
     96 		return curcpu;
     97 	}
     98 }
     99 
    100 /*
    101  * Override setcontext so that pthread private pointer is preserved
    102  */
    103 int
    104 pthread_setcontext(const ucontext_t *ucp)
    105 {
    106 #ifdef _UC_TLSBASE
    107 	ucontext_t uc;
    108 	/*
    109 	 * Only copy and clear _UC_TLSBASE if it is set.
    110 	 */
    111 	if (ucp->uc_flags & _UC_TLSBASE) {
    112 		uc = *ucp;
    113 		uc.uc_flags &= ~_UC_TLSBASE;
    114 		ucp = &uc;
    115 	}
    116 #endif /* _UC_TLSBASE */
    117 	return _sys_setcontext(ucp);
    118 }
    119