reentrant.h revision 1.22
1 /* $NetBSD: reentrant.h,v 1.22 2024/08/27 13:43:02 riastradh 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Requirements: 34 * 35 * 1. The thread safe mechanism should be lightweight so the library can 36 * be used by non-threaded applications without unreasonable overhead. 37 * 38 * 2. There should be no dependency on a thread engine for non-threaded 39 * applications. 40 * 41 * 3. There should be no dependency on any particular thread engine. 42 * 43 * 4. The library should be able to be compiled without support for thread 44 * safety. 45 * 46 * 47 * Rationale: 48 * 49 * One approach for thread safety is to provide discrete versions of the 50 * library: one thread safe, the other not. The disadvantage of this is 51 * that libc is rather large, and two copies of a library which are 99%+ 52 * identical is not an efficient use of resources. 53 * 54 * Another approach is to provide a single thread safe library. However, 55 * it should not add significant run time or code size overhead to non- 56 * threaded applications. 57 * 58 * Since the NetBSD C library is used in other projects, it should be 59 * easy to replace the mutual exclusion primitives with ones provided by 60 * another system. Similarly, it should also be easy to remove all 61 * support for thread safety completely if the target environment does 62 * not support threads. 63 * 64 * 65 * Implementation Details: 66 * 67 * The thread primitives used by the library (mutex_t, mutex_lock, etc.) 68 * are macros which expand to the cooresponding primitives provided by 69 * the thread engine or to nothing. The latter is used so that code is 70 * not unreasonably cluttered with #ifdefs when all thread safe support 71 * is removed. 72 * 73 * The thread macros can be directly mapped to the mutex primitives from 74 * pthreads, however it should be reasonably easy to wrap another mutex 75 * implementation so it presents a similar interface. 76 * 77 * The thread functions operate by dispatching to symbols which are, by 78 * default, weak-aliased to no-op functions in thread-stub/thread-stub.c 79 * (some uses of thread operations are conditional on __isthreaded, but 80 * not all of them are). 81 * 82 * When the thread library is linked in, it provides strong-alias versions 83 * of those symbols which dispatch to its own real thread operations. 84 * 85 */ 86 87 /* 88 * Abstract thread interface for thread-safe libraries. These routines 89 * will use stubs in libc if the application is not linked against the 90 * pthread library, and the real function in the pthread library if it 91 * is. 92 */ 93 94 #ifndef _LIBC_REENTRANT_H_ 95 #define _LIBC_REENTRANT_H_ 96 97 #include <pthread.h> 98 #include <signal.h> 99 100 #define mutex_t pthread_mutex_t 101 #define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER 102 103 #define mutexattr_t pthread_mutexattr_t 104 105 #define MUTEX_TYPE_NORMAL PTHREAD_MUTEX_NORMAL 106 #define MUTEX_TYPE_ERRORCHECK PTHREAD_MUTEX_ERRORCHECK 107 #define MUTEX_TYPE_RECURSIVE PTHREAD_MUTEX_RECURSIVE 108 109 #define cond_t pthread_cond_t 110 #define COND_INITIALIZER PTHREAD_COND_INITIALIZER 111 112 #define condattr_t pthread_condattr_t 113 114 #define rwlock_t pthread_rwlock_t 115 #define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER 116 117 #define rwlockattr_t pthread_rwlockattr_t 118 119 #define thread_key_t pthread_key_t 120 121 #define thr_t pthread_t 122 123 #define thrattr_t pthread_attr_t 124 125 #define once_t pthread_once_t 126 #define ONCE_INITIALIZER PTHREAD_ONCE_INIT 127 128 #ifdef _REENTRANT 129 130 #ifndef __LIBC_THREAD_STUBS 131 132 __BEGIN_DECLS 133 int __libc_mutex_init(mutex_t *, const mutexattr_t *); 134 int __libc_mutex_lock(mutex_t *); 135 int __libc_mutex_trylock(mutex_t *); 136 int __libc_mutex_unlock(mutex_t *); 137 int __libc_mutex_destroy(mutex_t *); 138 139 int __libc_mutexattr_init(mutexattr_t *); 140 int __libc_mutexattr_settype(mutexattr_t *, int); 141 int __libc_mutexattr_destroy(mutexattr_t *); 142 __END_DECLS 143 144 #define mutex_init(m, a) __libc_mutex_init((m), (a)) 145 #define mutex_lock(m) __libc_mutex_lock((m)) 146 #define mutex_trylock(m) __libc_mutex_trylock((m)) 147 #define mutex_unlock(m) __libc_mutex_unlock((m)) 148 #define mutex_destroy(m) __libc_mutex_destroy((m)) 149 150 #define mutexattr_init(ma) __libc_mutexattr_init((ma)) 151 #define mutexattr_settype(ma, t) __libc_mutexattr_settype((ma), (t)) 152 #define mutexattr_destroy(ma) __libc_mutexattr_destroy((ma)) 153 154 __BEGIN_DECLS 155 int __libc_cond_init(cond_t *, const condattr_t *); 156 int __libc_cond_signal(cond_t *); 157 int __libc_cond_broadcast(cond_t *); 158 int __libc_cond_wait(cond_t *, mutex_t *); 159 #ifndef __LIBC12_SOURCE__ 160 int __libc_cond_timedwait(cond_t *, mutex_t *, const struct timespec *); 161 #endif 162 int __libc_cond_destroy(cond_t *); 163 __END_DECLS 164 165 #define cond_init(c, t, a) __libc_cond_init((c), (a)) 166 #define cond_signal(c) __libc_cond_signal((c)) 167 #define cond_broadcast(c) __libc_cond_broadcast((c)) 168 #define cond_wait(c, m) __libc_cond_wait((c), (m)) 169 #define cond_timedwait(c, m, t) __libc_cond_timedwait((c), (m), (t)) 170 #define cond_destroy(c) __libc_cond_destroy((c)) 171 172 __BEGIN_DECLS 173 int __libc_rwlock_init(rwlock_t *, const rwlockattr_t *); 174 int __libc_rwlock_rdlock(rwlock_t *); 175 int __libc_rwlock_wrlock(rwlock_t *); 176 int __libc_rwlock_tryrdlock(rwlock_t *); 177 int __libc_rwlock_trywrlock(rwlock_t *); 178 int __libc_rwlock_unlock(rwlock_t *); 179 int __libc_rwlock_destroy(rwlock_t *); 180 __END_DECLS 181 182 #define rwlock_init(l, a) __libc_rwlock_init((l), (a)) 183 #define rwlock_rdlock(l) __libc_rwlock_rdlock((l)) 184 #define rwlock_wrlock(l) __libc_rwlock_wrlock((l)) 185 #define rwlock_tryrdlock(l) __libc_rwlock_tryrdlock((l)) 186 #define rwlock_trywrlock(l) __libc_rwlock_trywrlock((l)) 187 #define rwlock_unlock(l) __libc_rwlock_unlock((l)) 188 #define rwlock_destroy(l) __libc_rwlock_destroy((l)) 189 190 __BEGIN_DECLS 191 int __libc_thr_keycreate(thread_key_t *, void (*)(void *)); 192 int __libc_thr_setspecific(thread_key_t, const void *); 193 void *__libc_thr_getspecific(thread_key_t); 194 int __libc_thr_keydelete(thread_key_t); 195 __END_DECLS 196 197 #define thr_keycreate(k, d) __libc_thr_keycreate((k), (d)) 198 #define thr_setspecific(k, p) __libc_thr_setspecific((k), (p)) 199 #define thr_getspecific(k) __libc_thr_getspecific((k)) 200 #define thr_keydelete(k) __libc_thr_keydelete((k)) 201 202 __BEGIN_DECLS 203 int __libc_thr_once(once_t *, void (*)(void)); 204 int __libc_thr_sigsetmask(int, const sigset_t *, sigset_t *); 205 thr_t __libc_thr_self(void); 206 int __libc_thr_yield(void); 207 void __libc_thr_create(thr_t *, const thrattr_t *, 208 void *(*)(void *), void *); 209 void __libc_thr_exit(void *) __attribute__((__noreturn__)); 210 int *__libc_thr_errno(void); 211 int __libc_thr_setcancelstate(int, int *); 212 unsigned int __libc_thr_curcpu(void); 213 214 extern int __isthreaded; 215 __END_DECLS 216 217 #define thr_once(o, f) __libc_thr_once((o), (f)) 218 #define thr_sigsetmask(f, n, o) __libc_thr_sigsetmask((f), (n), (o)) 219 #define thr_self() __libc_thr_self() 220 #define thr_yield() __libc_thr_yield() 221 #define thr_create(tp, ta, f, a) __libc_thr_create((tp), (ta), (f), (a)) 222 #define thr_exit(v) __libc_thr_exit((v)) 223 #define thr_errno() __libc_thr_errno() 224 #define thr_enabled() (__isthreaded) 225 #define thr_setcancelstate(n, o) __libc_thr_setcancelstate((n),(o)) 226 #define thr_curcpu() __libc_thr_curcpu() 227 228 #else /* __LIBC_THREAD_STUBS */ 229 230 __BEGIN_DECLS 231 void __libc_thr_init_stub(void); 232 233 int __libc_mutex_init_stub(mutex_t *, const mutexattr_t *); 234 int __libc_mutex_lock_stub(mutex_t *); 235 int __libc_mutex_trylock_stub(mutex_t *); 236 int __libc_mutex_unlock_stub(mutex_t *); 237 int __libc_mutex_destroy_stub(mutex_t *); 238 239 int __libc_mutexattr_init_stub(mutexattr_t *); 240 int __libc_mutexattr_destroy_stub(mutexattr_t *); 241 int __libc_mutexattr_settype_stub(mutexattr_t *, int); 242 243 int __libc_cond_init_stub(cond_t *, const condattr_t *); 244 int __libc_cond_signal_stub(cond_t *); 245 int __libc_cond_broadcast_stub(cond_t *); 246 int __libc_cond_wait_stub(cond_t *, mutex_t *); 247 int __libc_cond_timedwait_stub(cond_t *, mutex_t *, 248 const struct timespec *); 249 int __libc_cond_destroy_stub(cond_t *); 250 251 int __libc_rwlock_init_stub(rwlock_t *, const rwlockattr_t *); 252 int __libc_rwlock_rdlock_stub(rwlock_t *); 253 int __libc_rwlock_wrlock_stub(rwlock_t *); 254 int __libc_rwlock_tryrdlock_stub(rwlock_t *); 255 int __libc_rwlock_trywrlock_stub(rwlock_t *); 256 int __libc_rwlock_unlock_stub(rwlock_t *); 257 int __libc_rwlock_destroy_stub(rwlock_t *); 258 259 int __libc_thr_keycreate_stub(thread_key_t *, void (*)(void *)); 260 int __libc_thr_setspecific_stub(thread_key_t, const void *); 261 void *__libc_thr_getspecific_stub(thread_key_t); 262 int __libc_thr_keydelete_stub(thread_key_t); 263 264 int __libc_thr_once_stub(once_t *, void (*)(void)); 265 int __libc_thr_sigsetmask_stub(int, const sigset_t *, sigset_t *); 266 thr_t __libc_thr_self_stub(void); 267 int __libc_thr_yield_stub(void); 268 int __libc_thr_create_stub(thr_t *, const thrattr_t *, 269 void *(*)(void *), void *); 270 void __libc_thr_exit_stub(void *) __dead; 271 int *__libc_thr_errno_stub(void); 272 int __libc_thr_setcancelstate_stub(int, int *); 273 int __libc_thr_equal_stub(pthread_t, pthread_t); 274 unsigned int __libc_thr_curcpu_stub(void); 275 __END_DECLS 276 277 #endif /* __LIBC_THREAD_STUBS */ 278 279 #define FLOCKFILE(fp) __flockfile_internal(fp, 1) 280 #define FUNLOCKFILE(fp) __funlockfile_internal(fp, 1) 281 282 #else /* _REENTRANT */ 283 284 #define mutex_init(m, a) __nothing 285 #define mutex_lock(m) __nothing 286 #define mutex_trylock(m) __nothing 287 #define mutex_unlock(m) __nothing 288 #define mutex_destroy(m) __nothing 289 290 #define cond_init(c, t, a) __nothing 291 #define cond_signal(c) __nothing 292 #define cond_broadcast(c) __nothing 293 #define cond_wait(c, m) __nothing 294 #define cond_timedwait(c, m, t) __nothing 295 #define cond_destroy(c) __nothing 296 297 #define rwlock_init(l, a) __nothing 298 #define rwlock_rdlock(l) __nothing 299 #define rwlock_wrlock(l) __nothing 300 #define rwlock_tryrdlock(l) __nothing 301 #define rwlock_trywrlock(l) __nothing 302 #define rwlock_unlock(l) __nothing 303 #define rwlock_destroy(l) __nothing 304 305 #define thr_keycreate(k, d) /*LINTED*/0 306 #define thr_setspecific(k, p) __nothing 307 #define thr_getspecific(k) /*LINTED*/0 308 #define thr_keydelete(k) __nothing 309 310 #define mutexattr_init(ma) __nothing 311 #define mutexattr_settype(ma, t) __nothing 312 #define mutexattr_destroy(ma) __nothing 313 314 static inline int 315 thr_once(once_t *once_control, void (*routine)(void)) 316 { 317 if (__predict_false(once_control->pto_done == 0)) { 318 (*routine)(); 319 once_control->pto_done = 1; 320 } 321 return 0; 322 } 323 #define thr_sigsetmask(f, n, o) __nothing 324 #define thr_self() __nothing 325 #define thr_errno() __nothing 326 #define thr_curcpu() ((unsigned int)0) 327 328 #define FLOCKFILE(fp) __nothing 329 #define FUNLOCKFILE(fp) __nothing 330 331 #endif /* _REENTRANT */ 332 333 #endif /* _LIBC_REENTRANT_H_ */ 334
Indexes created Mon Sep 22 21:09:42 GMT 2025