xref: /freebsd/lib/libc/include/reentrant.h (revision 33dee819339974eaf7dbf69068001771cbdcd548)
18360efbdSAlfred Perlstein /*-
28360efbdSAlfred Perlstein  * Copyright (c) 1997,98 The NetBSD Foundation, Inc.
38360efbdSAlfred Perlstein  * All rights reserved.
48360efbdSAlfred Perlstein  *
58360efbdSAlfred Perlstein  * This code is derived from software contributed to The NetBSD Foundation
68360efbdSAlfred Perlstein  * by J.T. Conklin.
78360efbdSAlfred Perlstein  *
88360efbdSAlfred Perlstein  * Redistribution and use in source and binary forms, with or without
98360efbdSAlfred Perlstein  * modification, are permitted provided that the following conditions
108360efbdSAlfred Perlstein  * are met:
118360efbdSAlfred Perlstein  * 1. Redistributions of source code must retain the above copyright
128360efbdSAlfred Perlstein  *    notice, this list of conditions and the following disclaimer.
138360efbdSAlfred Perlstein  * 2. Redistributions in binary form must reproduce the above copyright
148360efbdSAlfred Perlstein  *    notice, this list of conditions and the following disclaimer in the
158360efbdSAlfred Perlstein  *    documentation and/or other materials provided with the distribution.
168360efbdSAlfred Perlstein  * 3. All advertising materials mentioning features or use of this software
178360efbdSAlfred Perlstein  *    must display the following acknowledgement:
188360efbdSAlfred Perlstein  *        This product includes software developed by the NetBSD
198360efbdSAlfred Perlstein  *        Foundation, Inc. and its contributors.
208360efbdSAlfred Perlstein  * 4. Neither the name of The NetBSD Foundation nor the names of its
218360efbdSAlfred Perlstein  *    contributors may be used to endorse or promote products derived
228360efbdSAlfred Perlstein  *    from this software without specific prior written permission.
238360efbdSAlfred Perlstein  *
248360efbdSAlfred Perlstein  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
258360efbdSAlfred Perlstein  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
268360efbdSAlfred Perlstein  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
278360efbdSAlfred Perlstein  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
288360efbdSAlfred Perlstein  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
298360efbdSAlfred Perlstein  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
308360efbdSAlfred Perlstein  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
318360efbdSAlfred Perlstein  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
328360efbdSAlfred Perlstein  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
338360efbdSAlfred Perlstein  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
348360efbdSAlfred Perlstein  * POSSIBILITY OF SUCH DAMAGE.
358360efbdSAlfred Perlstein  *
368360efbdSAlfred Perlstein  * $FreeBSD$
378360efbdSAlfred Perlstein  */
388360efbdSAlfred Perlstein 
398360efbdSAlfred Perlstein /*
408360efbdSAlfred Perlstein  * Requirements:
418360efbdSAlfred Perlstein  *
428360efbdSAlfred Perlstein  * 1. The thread safe mechanism should be lightweight so the library can
438360efbdSAlfred Perlstein  *    be used by non-threaded applications without unreasonable overhead.
448360efbdSAlfred Perlstein  *
458360efbdSAlfred Perlstein  * 2. There should be no dependency on a thread engine for non-threaded
468360efbdSAlfred Perlstein  *    applications.
478360efbdSAlfred Perlstein  *
488360efbdSAlfred Perlstein  * 3. There should be no dependency on any particular thread engine.
498360efbdSAlfred Perlstein  *
508360efbdSAlfred Perlstein  * 4. The library should be able to be compiled without support for thread
518360efbdSAlfred Perlstein  *    safety.
528360efbdSAlfred Perlstein  *
538360efbdSAlfred Perlstein  *
548360efbdSAlfred Perlstein  * Rationale:
558360efbdSAlfred Perlstein  *
568360efbdSAlfred Perlstein  * One approach for thread safety is to provide discrete versions of the
578360efbdSAlfred Perlstein  * library: one thread safe, the other not.  The disadvantage of this is
588360efbdSAlfred Perlstein  * that libc is rather large, and two copies of a library which are 99%+
598360efbdSAlfred Perlstein  * identical is not an efficent use of resources.
608360efbdSAlfred Perlstein  *
618360efbdSAlfred Perlstein  * Another approach is to provide a single thread safe library.  However,
628360efbdSAlfred Perlstein  * it should not add significant run time or code size overhead to non-
638360efbdSAlfred Perlstein  * threaded applications.
648360efbdSAlfred Perlstein  *
658360efbdSAlfred Perlstein  * Since the NetBSD C library is used in other projects, it should be
668360efbdSAlfred Perlstein  * easy to replace the mutual exclusion primitives with ones provided by
678360efbdSAlfred Perlstein  * another system.  Similarly, it should also be easy to remove all
688360efbdSAlfred Perlstein  * support for thread safety completely if the target environment does
698360efbdSAlfred Perlstein  * not support threads.
708360efbdSAlfred Perlstein  *
718360efbdSAlfred Perlstein  *
728360efbdSAlfred Perlstein  * Implementation Details:
738360efbdSAlfred Perlstein  *
748360efbdSAlfred Perlstein  * The mutex primitives used by the library (mutex_t, mutex_lock, etc.)
758360efbdSAlfred Perlstein  * are macros which expand to the cooresponding primitives provided by
768360efbdSAlfred Perlstein  * the thread engine or to nothing.  The latter is used so that code is
778360efbdSAlfred Perlstein  * not unreasonably cluttered with #ifdefs when all thread safe support
788360efbdSAlfred Perlstein  * is removed.
798360efbdSAlfred Perlstein  *
808360efbdSAlfred Perlstein  * The mutex macros can be directly mapped to the mutex primitives from
818360efbdSAlfred Perlstein  * pthreads, however it should be reasonably easy to wrap another mutex
828360efbdSAlfred Perlstein  * implementation so it presents a similar interface.
838360efbdSAlfred Perlstein  *
848360efbdSAlfred Perlstein  * Stub implementations of the mutex functions are provided with *weak*
858360efbdSAlfred Perlstein  * linkage.  These functions simply return success.  When linked with a
868360efbdSAlfred Perlstein  * thread library (i.e. -lpthread), the functions will override the
878360efbdSAlfred Perlstein  * stubs.
888360efbdSAlfred Perlstein  */
898360efbdSAlfred Perlstein 
908360efbdSAlfred Perlstein #include <pthread.h>
918360efbdSAlfred Perlstein #include <pthread_np.h>
928360efbdSAlfred Perlstein #include "libc_private.h"
938360efbdSAlfred Perlstein 
948360efbdSAlfred Perlstein #define mutex_t			pthread_mutex_t
958360efbdSAlfred Perlstein #define cond_t			pthread_cond_t
968360efbdSAlfred Perlstein #define rwlock_t		pthread_rwlock_t
9733dee819SBrian Feldman #define once_t			pthread_once_t
988360efbdSAlfred Perlstein 
998360efbdSAlfred Perlstein #define thread_key_t		pthread_key_t
1008360efbdSAlfred Perlstein #define MUTEX_INITIALIZER	PTHREAD_MUTEX_INITIALIZER
1018360efbdSAlfred Perlstein #define RWLOCK_INITIALIZER	PTHREAD_RWLOCK_INITIALIZER
10233dee819SBrian Feldman #define ONCE_INITIALIZER	PTHREAD_ONCE_INIT
1038360efbdSAlfred Perlstein 
1048360efbdSAlfred Perlstein #define mutex_init(m, a)	_pthread_mutex_init(m, a)
1058360efbdSAlfred Perlstein #define mutex_lock(m)		if (__isthreaded) \
1068360efbdSAlfred Perlstein 				_pthread_mutex_lock(m)
1078360efbdSAlfred Perlstein #define mutex_unlock(m)		if (__isthreaded) \
1088360efbdSAlfred Perlstein 				_pthread_mutex_unlock(m)
1098360efbdSAlfred Perlstein #define mutex_trylock(m)	(__isthreaded ? 0 : _pthread_mutex_trylock(m))
1108360efbdSAlfred Perlstein 
1118360efbdSAlfred Perlstein #define cond_init(c, a, p)	_pthread_cond_init(c, a)
1128360efbdSAlfred Perlstein #define cond_signal(m)		if (__isthreaded) \
1138360efbdSAlfred Perlstein 				_pthread_cond_signal(m)
114ceb33671SDoug Rabson #define cond_broadcast(m)	if (__isthreaded) \
115ceb33671SDoug Rabson 				_pthread_cond_broadcast(m)
1168360efbdSAlfred Perlstein #define cond_wait(c, m)		if (__isthreaded) \
1178360efbdSAlfred Perlstein 				_pthread_cond_wait(c, m)
1188360efbdSAlfred Perlstein 
1198360efbdSAlfred Perlstein #define rwlock_init(l, a)	_pthread_rwlock_init(l, a)
1208360efbdSAlfred Perlstein #define rwlock_rdlock(l)	if (__isthreaded) \
1218360efbdSAlfred Perlstein 				_pthread_rwlock_rdlock(l)
1228360efbdSAlfred Perlstein #define rwlock_wrlock(l)	if (__isthreaded) \
1238360efbdSAlfred Perlstein 				_pthread_rwlock_wrlock(l)
1248360efbdSAlfred Perlstein #define rwlock_unlock(l)	if (__isthreaded) \
1258360efbdSAlfred Perlstein 				_pthread_rwlock_unlock(l)
1268360efbdSAlfred Perlstein 
1278360efbdSAlfred Perlstein #define thr_keycreate(k, d)	_pthread_key_create(k, d)
1288360efbdSAlfred Perlstein #define thr_setspecific(k, p)	_pthread_setspecific(k, p)
1298360efbdSAlfred Perlstein #define thr_getspecific(k)	_pthread_getspecific(k)
1308360efbdSAlfred Perlstein #define thr_sigsetmask(f, n, o)	_pthread_sigmask(f, n, o)
1318360efbdSAlfred Perlstein 
13233dee819SBrian Feldman #define thr_once(o, i)		_pthread_once(o, i)
1338360efbdSAlfred Perlstein #define thr_self()		_pthread_self()
1348360efbdSAlfred Perlstein #define thr_exit(x)		_pthread_exit(x)
1358360efbdSAlfred Perlstein #define thr_main()		_pthread_main_np()
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