1*86d7f5d3SJohn Marino /*- 2*86d7f5d3SJohn Marino * Copyright (c) 1997,98 The NetBSD Foundation, Inc. 3*86d7f5d3SJohn Marino * All rights reserved. 4*86d7f5d3SJohn Marino * 5*86d7f5d3SJohn Marino * This code is derived from software contributed to The NetBSD Foundation 6*86d7f5d3SJohn Marino * by J.T. Conklin. 7*86d7f5d3SJohn Marino * 8*86d7f5d3SJohn Marino * Redistribution and use in source and binary forms, with or without 9*86d7f5d3SJohn Marino * modification, are permitted provided that the following conditions 10*86d7f5d3SJohn Marino * are met: 11*86d7f5d3SJohn Marino * 1. Redistributions of source code must retain the above copyright 12*86d7f5d3SJohn Marino * notice, this list of conditions and the following disclaimer. 13*86d7f5d3SJohn Marino * 2. Redistributions in binary form must reproduce the above copyright 14*86d7f5d3SJohn Marino * notice, this list of conditions and the following disclaimer in the 15*86d7f5d3SJohn Marino * documentation and/or other materials provided with the distribution. 16*86d7f5d3SJohn Marino * 3. All advertising materials mentioning features or use of this software 17*86d7f5d3SJohn Marino * must display the following acknowledgement: 18*86d7f5d3SJohn Marino * This product includes software developed by the NetBSD 19*86d7f5d3SJohn Marino * Foundation, Inc. and its contributors. 20*86d7f5d3SJohn Marino * 4. Neither the name of The NetBSD Foundation nor the names of its 21*86d7f5d3SJohn Marino * contributors may be used to endorse or promote products derived 22*86d7f5d3SJohn Marino * from this software without specific prior written permission. 23*86d7f5d3SJohn Marino * 24*86d7f5d3SJohn Marino * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 25*86d7f5d3SJohn Marino * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 26*86d7f5d3SJohn Marino * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 27*86d7f5d3SJohn Marino * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 28*86d7f5d3SJohn Marino * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 29*86d7f5d3SJohn Marino * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30*86d7f5d3SJohn Marino * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31*86d7f5d3SJohn Marino * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32*86d7f5d3SJohn Marino * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 33*86d7f5d3SJohn Marino * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34*86d7f5d3SJohn Marino * POSSIBILITY OF SUCH DAMAGE. 35*86d7f5d3SJohn Marino * 36*86d7f5d3SJohn Marino * $FreeBSD: src/lib/libc/include/reentrant.h,v 1.3 2004/02/25 21:03:45 green Exp $ 37*86d7f5d3SJohn Marino */ 38*86d7f5d3SJohn Marino 39*86d7f5d3SJohn Marino /* 40*86d7f5d3SJohn Marino * Requirements: 41*86d7f5d3SJohn Marino * 42*86d7f5d3SJohn Marino * 1. The thread safe mechanism should be lightweight so the library can 43*86d7f5d3SJohn Marino * be used by non-threaded applications without unreasonable overhead. 44*86d7f5d3SJohn Marino * 45*86d7f5d3SJohn Marino * 2. There should be no dependency on a thread engine for non-threaded 46*86d7f5d3SJohn Marino * applications. 47*86d7f5d3SJohn Marino * 48*86d7f5d3SJohn Marino * 3. There should be no dependency on any particular thread engine. 49*86d7f5d3SJohn Marino * 50*86d7f5d3SJohn Marino * 4. The library should be able to be compiled without support for thread 51*86d7f5d3SJohn Marino * safety. 52*86d7f5d3SJohn Marino * 53*86d7f5d3SJohn Marino * 54*86d7f5d3SJohn Marino * Rationale: 55*86d7f5d3SJohn Marino * 56*86d7f5d3SJohn Marino * One approach for thread safety is to provide discrete versions of the 57*86d7f5d3SJohn Marino * library: one thread safe, the other not. The disadvantage of this is 58*86d7f5d3SJohn Marino * that libc is rather large, and two copies of a library which are 99%+ 59*86d7f5d3SJohn Marino * identical is not an efficent use of resources. 60*86d7f5d3SJohn Marino * 61*86d7f5d3SJohn Marino * Another approach is to provide a single thread safe library. However, 62*86d7f5d3SJohn Marino * it should not add significant run time or code size overhead to non- 63*86d7f5d3SJohn Marino * threaded applications. 64*86d7f5d3SJohn Marino * 65*86d7f5d3SJohn Marino * Since the NetBSD C library is used in other projects, it should be 66*86d7f5d3SJohn Marino * easy to replace the mutual exclusion primitives with ones provided by 67*86d7f5d3SJohn Marino * another system. Similarly, it should also be easy to remove all 68*86d7f5d3SJohn Marino * support for thread safety completely if the target environment does 69*86d7f5d3SJohn Marino * not support threads. 70*86d7f5d3SJohn Marino * 71*86d7f5d3SJohn Marino * 72*86d7f5d3SJohn Marino * Implementation Details: 73*86d7f5d3SJohn Marino * 74*86d7f5d3SJohn Marino * The mutex primitives used by the library (mutex_t, mutex_lock, etc.) 75*86d7f5d3SJohn Marino * are macros which expand to the cooresponding primitives provided by 76*86d7f5d3SJohn Marino * the thread engine or to nothing. The latter is used so that code is 77*86d7f5d3SJohn Marino * not unreasonably cluttered with #ifdefs when all thread safe support 78*86d7f5d3SJohn Marino * is removed. 79*86d7f5d3SJohn Marino * 80*86d7f5d3SJohn Marino * The mutex macros can be directly mapped to the mutex primitives from 81*86d7f5d3SJohn Marino * pthreads, however it should be reasonably easy to wrap another mutex 82*86d7f5d3SJohn Marino * implementation so it presents a similar interface. 83*86d7f5d3SJohn Marino * 84*86d7f5d3SJohn Marino * Stub implementations of the mutex functions are provided with *weak* 85*86d7f5d3SJohn Marino * linkage. These functions simply return success. When linked with a 86*86d7f5d3SJohn Marino * thread library (i.e. -lpthread), the functions will override the 87*86d7f5d3SJohn Marino * stubs. 88*86d7f5d3SJohn Marino */ 89*86d7f5d3SJohn Marino 90*86d7f5d3SJohn Marino #include <pthread.h> 91*86d7f5d3SJohn Marino #include <pthread_np.h> 92*86d7f5d3SJohn Marino #include "libc_private.h" 93*86d7f5d3SJohn Marino 94*86d7f5d3SJohn Marino #define mutex_t pthread_mutex_t 95*86d7f5d3SJohn Marino #define cond_t pthread_cond_t 96*86d7f5d3SJohn Marino #define rwlock_t pthread_rwlock_t 97*86d7f5d3SJohn Marino #define once_t pthread_once_t 98*86d7f5d3SJohn Marino 99*86d7f5d3SJohn Marino #define thread_key_t pthread_key_t 100*86d7f5d3SJohn Marino #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER 101*86d7f5d3SJohn Marino #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER 102*86d7f5d3SJohn Marino #define ONCE_INITIALIZER PTHREAD_ONCE_INIT 103*86d7f5d3SJohn Marino 104*86d7f5d3SJohn Marino #define mutex_init(m, a) _pthread_mutex_init(m, a) 105*86d7f5d3SJohn Marino #define mutex_lock(m) if (__isthreaded) \ 106*86d7f5d3SJohn Marino _pthread_mutex_lock(m) 107*86d7f5d3SJohn Marino #define mutex_unlock(m) if (__isthreaded) \ 108*86d7f5d3SJohn Marino _pthread_mutex_unlock(m) 109*86d7f5d3SJohn Marino #define mutex_trylock(m) (__isthreaded ? 0 : _pthread_mutex_trylock(m)) 110*86d7f5d3SJohn Marino 111*86d7f5d3SJohn Marino #define cond_init(c, a, p) _pthread_cond_init(c, a) 112*86d7f5d3SJohn Marino #define cond_signal(m) if (__isthreaded) \ 113*86d7f5d3SJohn Marino _pthread_cond_signal(m) 114*86d7f5d3SJohn Marino #define cond_broadcast(m) if (__isthreaded) \ 115*86d7f5d3SJohn Marino _pthread_cond_broadcast(m) 116*86d7f5d3SJohn Marino #define cond_wait(c, m) if (__isthreaded) \ 117*86d7f5d3SJohn Marino _pthread_cond_wait(c, m) 118*86d7f5d3SJohn Marino 119*86d7f5d3SJohn Marino #define rwlock_init(l, a) _pthread_rwlock_init(l, a) 120*86d7f5d3SJohn Marino #define rwlock_rdlock(l) if (__isthreaded) \ 121*86d7f5d3SJohn Marino _pthread_rwlock_rdlock(l) 122*86d7f5d3SJohn Marino #define rwlock_wrlock(l) if (__isthreaded) \ 123*86d7f5d3SJohn Marino _pthread_rwlock_wrlock(l) 124*86d7f5d3SJohn Marino #define rwlock_unlock(l) if (__isthreaded) \ 125*86d7f5d3SJohn Marino _pthread_rwlock_unlock(l) 126*86d7f5d3SJohn Marino 127*86d7f5d3SJohn Marino #define thr_keycreate(k, d) _pthread_key_create(k, d) 128*86d7f5d3SJohn Marino #define thr_setspecific(k, p) _pthread_setspecific(k, p) 129*86d7f5d3SJohn Marino #define thr_getspecific(k) _pthread_getspecific(k) 130*86d7f5d3SJohn Marino #define thr_sigsetmask(f, n, o) _pthread_sigmask(f, n, o) 131*86d7f5d3SJohn Marino 132*86d7f5d3SJohn Marino #define thr_once(o, i) _pthread_once(o, i) 133*86d7f5d3SJohn Marino #define thr_self() _pthread_self() 134*86d7f5d3SJohn Marino #define thr_exit(x) _pthread_exit(x) 135*86d7f5d3SJohn Marino #define thr_main() _pthread_main_np() 136