174462Salfred/*- 274462Salfred * Copyright (c) 1997,98 The NetBSD Foundation, Inc. 374462Salfred * All rights reserved. 474462Salfred * 574462Salfred * This code is derived from software contributed to The NetBSD Foundation 674462Salfred * by J.T. Conklin. 774462Salfred * 874462Salfred * Redistribution and use in source and binary forms, with or without 974462Salfred * modification, are permitted provided that the following conditions 1074462Salfred * are met: 1174462Salfred * 1. Redistributions of source code must retain the above copyright 1274462Salfred * notice, this list of conditions and the following disclaimer. 1374462Salfred * 2. Redistributions in binary form must reproduce the above copyright 1474462Salfred * notice, this list of conditions and the following disclaimer in the 1574462Salfred * documentation and/or other materials provided with the distribution. 1674462Salfred * 1774462Salfred * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 1874462Salfred * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 1974462Salfred * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2074462Salfred * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 2174462Salfred * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 2274462Salfred * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 2374462Salfred * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 2474462Salfred * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 2574462Salfred * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 2674462Salfred * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 2774462Salfred * POSSIBILITY OF SUCH DAMAGE. 2874462Salfred * 2974462Salfred * $FreeBSD$ 3074462Salfred */ 3174462Salfred 3274462Salfred/* 3374462Salfred * Requirements: 3474462Salfred * 3574462Salfred * 1. The thread safe mechanism should be lightweight so the library can 3674462Salfred * be used by non-threaded applications without unreasonable overhead. 3774462Salfred * 3874462Salfred * 2. There should be no dependency on a thread engine for non-threaded 3974462Salfred * applications. 4074462Salfred * 4174462Salfred * 3. There should be no dependency on any particular thread engine. 4274462Salfred * 4374462Salfred * 4. The library should be able to be compiled without support for thread 4474462Salfred * safety. 4574462Salfred * 4674462Salfred * 4774462Salfred * Rationale: 4874462Salfred * 4974462Salfred * One approach for thread safety is to provide discrete versions of the 5074462Salfred * library: one thread safe, the other not. The disadvantage of this is 5174462Salfred * that libc is rather large, and two copies of a library which are 99%+ 5274462Salfred * identical is not an efficent use of resources. 5374462Salfred * 5474462Salfred * Another approach is to provide a single thread safe library. However, 5574462Salfred * it should not add significant run time or code size overhead to non- 5674462Salfred * threaded applications. 5774462Salfred * 5874462Salfred * Since the NetBSD C library is used in other projects, it should be 5974462Salfred * easy to replace the mutual exclusion primitives with ones provided by 6074462Salfred * another system. Similarly, it should also be easy to remove all 6174462Salfred * support for thread safety completely if the target environment does 6274462Salfred * not support threads. 6374462Salfred * 6474462Salfred * 6574462Salfred * Implementation Details: 6674462Salfred * 6774462Salfred * The mutex primitives used by the library (mutex_t, mutex_lock, etc.) 6874462Salfred * are macros which expand to the cooresponding primitives provided by 6974462Salfred * the thread engine or to nothing. The latter is used so that code is 7074462Salfred * not unreasonably cluttered with #ifdefs when all thread safe support 7174462Salfred * is removed. 7274462Salfred * 7374462Salfred * The mutex macros can be directly mapped to the mutex primitives from 7474462Salfred * pthreads, however it should be reasonably easy to wrap another mutex 7574462Salfred * implementation so it presents a similar interface. 7674462Salfred * 7774462Salfred * Stub implementations of the mutex functions are provided with *weak* 7874462Salfred * linkage. These functions simply return success. When linked with a 7974462Salfred * thread library (i.e. -lpthread), the functions will override the 8074462Salfred * stubs. 8174462Salfred */ 8274462Salfred 8374462Salfred#include <pthread.h> 8474462Salfred#include <pthread_np.h> 8574462Salfred#include "libc_private.h" 8674462Salfred 8774462Salfred#define mutex_t pthread_mutex_t 8874462Salfred#define cond_t pthread_cond_t 8974462Salfred#define rwlock_t pthread_rwlock_t 90126243Sgreen#define once_t pthread_once_t 9174462Salfred 9274462Salfred#define thread_key_t pthread_key_t 9374462Salfred#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER 9474462Salfred#define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER 95126243Sgreen#define ONCE_INITIALIZER PTHREAD_ONCE_INIT 9674462Salfred 9774462Salfred#define mutex_init(m, a) _pthread_mutex_init(m, a) 9874462Salfred#define mutex_lock(m) if (__isthreaded) \ 9974462Salfred _pthread_mutex_lock(m) 10074462Salfred#define mutex_unlock(m) if (__isthreaded) \ 10174462Salfred _pthread_mutex_unlock(m) 10274462Salfred#define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m)) 10374462Salfred 10474462Salfred#define cond_init(c, a, p) _pthread_cond_init(c, a) 10574462Salfred#define cond_signal(m) if (__isthreaded) \ 10674462Salfred _pthread_cond_signal(m) 107106288Sdfr#define cond_broadcast(m) if (__isthreaded) \ 108106288Sdfr _pthread_cond_broadcast(m) 10974462Salfred#define cond_wait(c, m) if (__isthreaded) \ 11074462Salfred _pthread_cond_wait(c, m) 11174462Salfred 11274462Salfred#define rwlock_init(l, a) _pthread_rwlock_init(l, a) 11374462Salfred#define rwlock_rdlock(l) if (__isthreaded) \ 11474462Salfred _pthread_rwlock_rdlock(l) 11574462Salfred#define rwlock_wrlock(l) if (__isthreaded) \ 11674462Salfred _pthread_rwlock_wrlock(l) 11774462Salfred#define rwlock_unlock(l) if (__isthreaded) \ 11874462Salfred _pthread_rwlock_unlock(l) 11974462Salfred 12074462Salfred#define thr_keycreate(k, d) _pthread_key_create(k, d) 12174462Salfred#define thr_setspecific(k, p) _pthread_setspecific(k, p) 12274462Salfred#define thr_getspecific(k) _pthread_getspecific(k) 12374462Salfred#define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o) 12474462Salfred 125126243Sgreen#define thr_once(o, i) _pthread_once(o, i) 12674462Salfred#define thr_self() _pthread_self() 12774462Salfred#define thr_exit(x) _pthread_exit(x) 12874462Salfred#define thr_main() _pthread_main_np() 129