1 /* $NetBSD: reentrant.h,v 1.10 2004/12/14 00:23:19 nathanw Exp $ */ 2 3 /*- 4 * Copyright (c) 1997, 1998, 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by J.T. Conklin, by Nathan J. Williams, and by Jason R. Thorpe. 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Requirements: 41 * 42 * 1. The thread safe mechanism should be lightweight so the library can 43 * be used by non-threaded applications without unreasonable overhead. 44 * 45 * 2. There should be no dependency on a thread engine for non-threaded 46 * applications. 47 * 48 * 3. There should be no dependency on any particular thread engine. 49 * 50 * 4. The library should be able to be compiled without support for thread 51 * safety. 52 * 53 * 54 * Rationale: 55 * 56 * One approach for thread safety is to provide discrete versions of the 57 * library: one thread safe, the other not. The disadvantage of this is 58 * that libc is rather large, and two copies of a library which are 99%+ 59 * identical is not an efficent use of resources. 60 * 61 * Another approach is to provide a single thread safe library. However, 62 * it should not add significant run time or code size overhead to non- 63 * threaded applications. 64 * 65 * Since the NetBSD C library is used in other projects, it should be 66 * easy to replace the mutual exclusion primitives with ones provided by 67 * another system. Similarly, it should also be easy to remove all 68 * support for thread safety completely if the target environment does 69 * not support threads. 70 * 71 * 72 * Implementation Details: 73 * 74 * The thread primitives used by the library (mutex_t, mutex_lock, etc.) 75 * are macros which expand to the cooresponding primitives provided by 76 * the thread engine or to nothing. The latter is used so that code is 77 * not unreasonably cluttered with #ifdefs when all thread safe support 78 * is removed. 79 * 80 * The thread macros can be directly mapped to the mutex primitives from 81 * pthreads, however it should be reasonably easy to wrap another mutex 82 * implementation so it presents a similar interface. 83 * 84 * The thread functions operate by dispatching to symbols which are, by 85 * default, weak-aliased to no-op functions in thread-stub/thread-stub.c 86 * (some uses of thread operations are conditional on __isthreaded, but 87 * not all of them are). 88 * 89 * When the thread library is linked in, it provides strong-alias versions 90 * of those symbols which dispatch to its own real thread operations. 91 * 92 */ 93 94 #ifdef _REENTRANT 95 96 /* 97 * Abtract thread interface for thread-safe libraries. These routines 98 * will use stubs in libc if the application is not linked against the 99 * pthread library, and the real function in the pthread library if it 100 * is. 101 */ 102 103 #include <pthread.h> 104 #include <signal.h> 105 106 #define mutex_t pthread_mutex_t 107 #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER 108 109 #define mutexattr_t pthread_mutexattr_t 110 111 #define MUTEX_TYPE_NORMAL PTHREAD_MUTEX_NORMAL 112 #define MUTEX_TYPE_ERRORCHECK PTHREAD_MUTEX_ERRORCHECK 113 #define MUTEX_TYPE_RECURSIVE PTHREAD_MUTEX_RECURSIVE 114 115 #define cond_t pthread_cond_t 116 #define COND_INITIALIZER PTHREAD_COND_INITIALIZER 117 118 #define condattr_t pthread_condattr_t 119 120 #define rwlock_t pthread_rwlock_t 121 #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER 122 123 #define rwlockattr_t pthread_rwlockattr_t 124 125 #define thread_key_t pthread_key_t 126 127 #define thr_t pthread_t 128 129 #define thrattr_t pthread_attr_t 130 131 #define once_t pthread_once_t 132 #define ONCE_INITIALIZER PTHREAD_ONCE_INIT 133 134 #ifndef __LIBC_THREAD_STUBS 135 136 __BEGIN_DECLS 137 int __libc_mutex_init(mutex_t *, const mutexattr_t *); 138 int __libc_mutex_lock(mutex_t *); 139 int __libc_mutex_trylock(mutex_t *); 140 int __libc_mutex_unlock(mutex_t *); 141 int __libc_mutex_destroy(mutex_t *); 142 143 int __libc_mutexattr_init(mutexattr_t *); 144 int __libc_mutexattr_settype(mutexattr_t *, int); 145 int __libc_mutexattr_destroy(mutexattr_t *); 146 __END_DECLS 147 148 #define mutex_init(m, a) __libc_mutex_init((m), (a)) 149 #define mutex_lock(m) __libc_mutex_lock((m)) 150 #define mutex_trylock(m) __libc_mutex_trylock((m)) 151 #define mutex_unlock(m) __libc_mutex_unlock((m)) 152 #define mutex_destroy(m) __libc_mutex_destroy((m)) 153 154 #define mutexattr_init(ma) __libc_mutexattr_init((ma)) 155 #define mutexattr_settype(ma, t) __libc_mutexattr_settype((ma), (t)) 156 #define mutexattr_destroy(ma) __libc_mutexattr_destroy((ma)) 157 158 __BEGIN_DECLS 159 int __libc_cond_init(cond_t *, const condattr_t *); 160 int __libc_cond_signal(cond_t *); 161 int __libc_cond_broadcast(cond_t *); 162 int __libc_cond_wait(cond_t *, mutex_t *); 163 int __libc_cond_timedwait(cond_t *, mutex_t *, const struct timespec *); 164 int __libc_cond_destroy(cond_t *); 165 __END_DECLS 166 167 #define cond_init(c, t, a) __libc_cond_init((c), (a)) 168 #define cond_signal(c) __libc_cond_signal((c)) 169 #define cond_broadcast(c) __libc_cond_broadcast((c)) 170 #define cond_wait(c, m) __libc_cond_wait((c), (m)) 171 #define cond_timedwait(c, m, t) __libc_cond_timedwait((c), (m), (t)) 172 #define cond_destroy(c) __libc_cond_destroy((c)) 173 174 __BEGIN_DECLS 175 int __libc_rwlock_init(rwlock_t *, const rwlockattr_t *); 176 int __libc_rwlock_rdlock(rwlock_t *); 177 int __libc_rwlock_wrlock(rwlock_t *); 178 int __libc_rwlock_tryrdlock(rwlock_t *); 179 int __libc_rwlock_trywrlock(rwlock_t *); 180 int __libc_rwlock_unlock(rwlock_t *); 181 int __libc_rwlock_destroy(rwlock_t *); 182 __END_DECLS 183 184 #define rwlock_init(l, a) __libc_rwlock_init((l), (a)) 185 #define rwlock_rdlock(l) __libc_rwlock_rdlock((l)) 186 #define rwlock_wrlock(l) __libc_rwlock_wrlock((l)) 187 #define rwlock_tryrdlock(l) __libc_rwlock_tryrdlock((l)) 188 #define rwlock_trywrlock(l) __libc_rwlock_trywrlock((l)) 189 #define rwlock_unlock(l) __libc_rwlock_unlock((l)) 190 #define rwlock_destroy(l) __libc_rwlock_destroy((l)) 191 192 __BEGIN_DECLS 193 int __libc_thr_keycreate(thread_key_t *, void (*)(void *)); 194 int __libc_thr_setspecific(thread_key_t, const void *); 195 void *__libc_thr_getspecific(thread_key_t); 196 int __libc_thr_keydelete(thread_key_t); 197 __END_DECLS 198 199 #define thr_keycreate(k, d) __libc_thr_keycreate((k), (d)) 200 #define thr_setspecific(k, p) __libc_thr_setspecific((k), (p)) 201 #define thr_getspecific(k) __libc_thr_getspecific((k)) 202 #define thr_keydelete(k) __libc_thr_keydelete((k)) 203 204 __BEGIN_DECLS 205 int __libc_thr_once(once_t *, void (*)(void)); 206 int __libc_thr_sigsetmask(int, const sigset_t *, sigset_t *); 207 thr_t __libc_thr_self(void); 208 int __libc_thr_yield(void); 209 void __libc_thr_create(thr_t *, const thrattr_t *, 210 void *(*)(void *), void *); 211 void __libc_thr_exit(void *) __attribute__((__noreturn__)); 212 int *__libc_thr_errno(void); 213 int __libc_thr_setcancelstate(int, int *); 214 215 extern int __isthreaded; 216 __END_DECLS 217 218 #define thr_once(o, f) __libc_thr_once((o), (f)) 219 #define thr_sigsetmask(f, n, o) __libc_thr_sigsetmask((f), (n), (o)) 220 #define thr_self() __libc_thr_self() 221 #define thr_yield() __libc_thr_yield() 222 #define thr_create(tp, ta, f, a) __libc_thr_create((tp), (ta), (f), (a)) 223 #define thr_exit(v) __libc_thr_exit((v)) 224 #define thr_errno() __libc_thr_errno() 225 #define thr_enabled() (__isthreaded) 226 #define thr_setcancelstate(n, o) __libc_thr_setcancelstate((n),(o)) 227 #endif /* __LIBC_THREAD_STUBS */ 228 229 #define FLOCKFILE(fp) __flockfile_internal(fp, 1) 230 #define FUNLOCKFILE(fp) __funlockfile_internal(fp, 1) 231 232 #else /* _REENTRANT */ 233 234 #define mutex_init(m, a) 235 #define mutex_lock(m) 236 #define mutex_trylock(m) 237 #define mutex_unlock(m) 238 #define mutex_destroy(m) 239 240 #define cond_init(c, t, a) 241 #define cond_signal(c) 242 #define cond_broadcast(c) 243 #define cond_wait(c, m) 244 #define cond_timedwait(c, m, t) 245 #define cond_destroy(c) 246 247 #define rwlock_init(l, a) 248 #define rwlock_rdlock(l) 249 #define rwlock_wrlock(l) 250 #define rwlock_tryrdlock(l) 251 #define rwlock_trywrlock(l) 252 #define rwlock_unlock(l) 253 #define rwlock_destroy(l) 254 255 #define thr_keycreate(k, d) 256 #define thr_setspecific(k, p) 257 #define thr_getspecific(k) 258 #define thr_keydelete(k) 259 260 #define thr_once(o, f) 261 #define thr_sigsetmask(f, n, o) 262 #define thr_self() 263 #define thr_errno() 264 265 #define FLOCKFILE(fp) 266 #define FUNLOCKFILE(fp) 267 268 #endif /* _REENTRANT */ 269