/*- * Copyright (c) 1997,98 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by J.T. Conklin. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: src/lib/libc/include/reentrant.h,v 1.3 2004/02/25 21:03:45 green Exp $ */ /* * Requirements: * * 1. The thread safe mechanism should be lightweight so the library can * be used by non-threaded applications without unreasonable overhead. * * 2. There should be no dependency on a thread engine for non-threaded * applications. * * 3. There should be no dependency on any particular thread engine. * * 4. The library should be able to be compiled without support for thread * safety. * * * Rationale: * * One approach for thread safety is to provide discrete versions of the * library: one thread safe, the other not. The disadvantage of this is * that libc is rather large, and two copies of a library which are 99%+ * identical is not an efficent use of resources. * * Another approach is to provide a single thread safe library. However, * it should not add significant run time or code size overhead to non- * threaded applications. * * Since the NetBSD C library is used in other projects, it should be * easy to replace the mutual exclusion primitives with ones provided by * another system. Similarly, it should also be easy to remove all * support for thread safety completely if the target environment does * not support threads. * * * Implementation Details: * * The mutex primitives used by the library (mutex_t, mutex_lock, etc.) * are macros which expand to the cooresponding primitives provided by * the thread engine or to nothing. The latter is used so that code is * not unreasonably cluttered with #ifdefs when all thread safe support * is removed. * * The mutex macros can be directly mapped to the mutex primitives from * pthreads, however it should be reasonably easy to wrap another mutex * implementation so it presents a similar interface. * * Stub implementations of the mutex functions are provided with *weak* * linkage. These functions simply return success. When linked with a * thread library (i.e. -lpthread), the functions will override the * stubs. */ #include <pthread.h> #include "libc_private.h" #define mutex_t pthread_mutex_t #define cond_t pthread_cond_t #define rwlock_t pthread_rwlock_t #define once_t pthread_once_t #define thread_key_t pthread_key_t #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER #define ONCE_INITIALIZER PTHREAD_ONCE_INIT #define mutex_init(m, a) _pthread_mutex_init(m, a) #define mutex_lock(m) if (__isthreaded) \ _pthread_mutex_lock(m) #define mutex_unlock(m) if (__isthreaded) \ _pthread_mutex_unlock(m) #define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m)) #define cond_init(c, a, p) _pthread_cond_init(c, a) #define cond_signal(m) if (__isthreaded) \ _pthread_cond_signal(m) #define cond_broadcast(m) if (__isthreaded) \ _pthread_cond_broadcast(m) #define cond_wait(c, m) if (__isthreaded) \ _pthread_cond_wait(c, m) #define rwlock_init(l, a) _pthread_rwlock_init(l, a) #define rwlock_rdlock(l) if (__isthreaded) \ _pthread_rwlock_rdlock(l) #define rwlock_wrlock(l) if (__isthreaded) \ _pthread_rwlock_wrlock(l) #define rwlock_unlock(l) if (__isthreaded) \ _pthread_rwlock_unlock(l) #define thr_keycreate(k, d) _pthread_key_create(k, d) #define thr_setspecific(k, p) _pthread_setspecific(k, p) #define thr_getspecific(k) _pthread_getspecific(k) #define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o) #define thr_once(o, i) _pthread_once(o, i) #define thr_self() _pthread_self() #define thr_exit(x) _pthread_exit(x) #define thr_main() _pthread_main_np()