1 /* $NetBSD: evthread-internal.h,v 1.7 2024/08/18 20:47:21 christos Exp $ */ 2 3 /* 4 * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 #ifndef EVTHREAD_INTERNAL_H_INCLUDED_ 29 #define EVTHREAD_INTERNAL_H_INCLUDED_ 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 #include "event2/event-config.h" 36 #include "evconfig-private.h" 37 38 #include "event2/thread.h" 39 #include "util-internal.h" 40 41 struct event_base; 42 43 #if !defined(_WIN32) && !defined(__CYGWIN__) 44 /* On Windows, the way we currently make DLLs, it's not allowed for us to 45 * have shared global structures. Thus, we only do the direct-call-to-function 46 * code path if we know that the local shared library system supports it. 47 */ 48 #define EVTHREAD_EXPOSE_STRUCTS 49 #endif 50 51 #if ! defined(EVENT__DISABLE_THREAD_SUPPORT) && defined(EVTHREAD_EXPOSE_STRUCTS) 52 /* Global function pointers to lock-related functions. NULL if locking isn't 53 enabled. */ 54 EVENT2_EXPORT_SYMBOL 55 extern struct evthread_lock_callbacks evthread_lock_fns_; 56 EVENT2_EXPORT_SYMBOL 57 extern struct evthread_condition_callbacks evthread_cond_fns_; 58 extern unsigned long (*evthread_id_fn_)(void); 59 EVENT2_EXPORT_SYMBOL 60 extern int evthread_lock_debugging_enabled_; 61 62 /** Return the ID of the current thread, or 1 if threading isn't enabled. */ 63 #define EVTHREAD_GET_ID() \ 64 (evthread_id_fn_ ? evthread_id_fn_() : 1) 65 66 /** Return true iff we're in the thread that is currently (or most recently) 67 * running a given event_base's loop. Requires lock. */ 68 #define EVBASE_IN_THREAD(base) \ 69 (evthread_id_fn_ == NULL || \ 70 (base)->th_owner_id == evthread_id_fn_()) 71 72 /** Return true iff we need to notify the base's main thread about changes to 73 * its state, because it's currently running the main loop in another 74 * thread. Requires lock. */ 75 #define EVBASE_NEED_NOTIFY(base) \ 76 (evthread_id_fn_ != NULL && \ 77 (base)->running_loop && \ 78 (base)->th_owner_id != evthread_id_fn_()) 79 80 /** Allocate a new lock, and store it in lockvar, a void*. Sets lockvar to 81 NULL if locking is not enabled. */ 82 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 83 ((lockvar) = evthread_lock_fns_.alloc ? \ 84 evthread_lock_fns_.alloc(locktype) : NULL) 85 86 /** Free a given lock, if it is present and locking is enabled. */ 87 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 88 do { \ 89 void *lock_tmp_ = (lockvar); \ 90 if (lock_tmp_ && evthread_lock_fns_.free) \ 91 evthread_lock_fns_.free(lock_tmp_, (locktype)); \ 92 } while (0) 93 94 /** Acquire a lock. */ 95 #define EVLOCK_LOCK(lockvar,mode) \ 96 do { \ 97 if (lockvar) \ 98 evthread_lock_fns_.lock(mode, lockvar); \ 99 } while (0) 100 101 /** Release a lock */ 102 #define EVLOCK_UNLOCK(lockvar,mode) \ 103 do { \ 104 if (lockvar) \ 105 evthread_lock_fns_.unlock(mode, lockvar); \ 106 } while (0) 107 108 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 109 #define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ 110 do { \ 111 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 112 void *tmp = lockvar1; \ 113 lockvar1 = lockvar2; \ 114 lockvar2 = tmp; \ 115 } \ 116 } while (0) 117 118 /** Lock an event_base, if it is set up for locking. Acquires the lock 119 in the base structure whose field is named 'lockvar'. */ 120 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 121 EVLOCK_LOCK((base)->lockvar, 0); \ 122 } while (0) 123 124 /** Unlock an event_base, if it is set up for locking. */ 125 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 126 EVLOCK_UNLOCK((base)->lockvar, 0); \ 127 } while (0) 128 129 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 130 * locked and held by us. */ 131 #define EVLOCK_ASSERT_LOCKED(lock) \ 132 do { \ 133 if ((lock) && evthread_lock_debugging_enabled_) { \ 134 EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ 135 } \ 136 } while (0) 137 138 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 139 * manage to get it. */ 140 static inline int EVLOCK_TRY_LOCK_(void *lock); 141 static inline int 142 EVLOCK_TRY_LOCK_(void *lock) 143 { 144 if (lock && evthread_lock_fns_.lock) { 145 int r = evthread_lock_fns_.lock(EVTHREAD_TRY, lock); 146 return !r; 147 } else { 148 /* Locking is disabled either globally or for this thing; 149 * of course we count as having the lock. */ 150 return 1; 151 } 152 } 153 154 /** Allocate a new condition variable and store it in the void *, condvar */ 155 #define EVTHREAD_ALLOC_COND(condvar) \ 156 do { \ 157 (condvar) = evthread_cond_fns_.alloc_condition ? \ 158 evthread_cond_fns_.alloc_condition(0) : NULL; \ 159 } while (0) 160 /** Deallocate and free a condition variable in condvar */ 161 #define EVTHREAD_FREE_COND(cond) \ 162 do { \ 163 if (cond) \ 164 evthread_cond_fns_.free_condition((cond)); \ 165 } while (0) 166 /** Signal one thread waiting on cond */ 167 #define EVTHREAD_COND_SIGNAL(cond) \ 168 ( (cond) ? evthread_cond_fns_.signal_condition((cond), 0) : 0 ) 169 /** Signal all threads waiting on cond */ 170 #define EVTHREAD_COND_BROADCAST(cond) \ 171 ( (cond) ? evthread_cond_fns_.signal_condition((cond), 1) : 0 ) 172 /** Wait until the condition 'cond' is signalled. Must be called while 173 * holding 'lock'. The lock will be released until the condition is 174 * signalled, at which point it will be acquired again. Returns 0 for 175 * success, -1 for failure. */ 176 #define EVTHREAD_COND_WAIT(cond, lock) \ 177 ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), NULL) : 0 ) 178 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 179 * on timeout. */ 180 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 181 ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), (tv)) : 0 ) 182 183 /** True iff locking functions have been configured. */ 184 #define EVTHREAD_LOCKING_ENABLED() \ 185 (evthread_lock_fns_.lock != NULL) 186 187 #elif ! defined(EVENT__DISABLE_THREAD_SUPPORT) 188 189 unsigned long evthreadimpl_get_id_(void); 190 EVENT2_EXPORT_SYMBOL 191 int evthreadimpl_is_lock_debugging_enabled_(void); 192 EVENT2_EXPORT_SYMBOL 193 void *evthreadimpl_lock_alloc_(unsigned locktype); 194 EVENT2_EXPORT_SYMBOL 195 void evthreadimpl_lock_free_(void *lock, unsigned locktype); 196 EVENT2_EXPORT_SYMBOL 197 int evthreadimpl_lock_lock_(unsigned mode, void *lock); 198 EVENT2_EXPORT_SYMBOL 199 int evthreadimpl_lock_unlock_(unsigned mode, void *lock); 200 EVENT2_EXPORT_SYMBOL 201 void *evthreadimpl_cond_alloc_(unsigned condtype); 202 EVENT2_EXPORT_SYMBOL 203 void evthreadimpl_cond_free_(void *cond); 204 EVENT2_EXPORT_SYMBOL 205 int evthreadimpl_cond_signal_(void *cond, int broadcast); 206 EVENT2_EXPORT_SYMBOL 207 int evthreadimpl_cond_wait_(void *cond, void *lock, const struct timeval *tv); 208 int evthreadimpl_locking_enabled_(void); 209 210 #define EVTHREAD_GET_ID() evthreadimpl_get_id_() 211 #define EVBASE_IN_THREAD(base) \ 212 ((base)->th_owner_id == evthreadimpl_get_id_()) 213 #define EVBASE_NEED_NOTIFY(base) \ 214 ((base)->running_loop && \ 215 ((base)->th_owner_id != evthreadimpl_get_id_())) 216 217 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 218 ((lockvar) = evthreadimpl_lock_alloc_(locktype)) 219 220 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 221 do { \ 222 void *lock_tmp_ = (lockvar); \ 223 if (lock_tmp_) \ 224 evthreadimpl_lock_free_(lock_tmp_, (locktype)); \ 225 } while (0) 226 227 /** Acquire a lock. */ 228 #define EVLOCK_LOCK(lockvar,mode) \ 229 do { \ 230 if (lockvar) \ 231 evthreadimpl_lock_lock_(mode, lockvar); \ 232 } while (0) 233 234 /** Release a lock */ 235 #define EVLOCK_UNLOCK(lockvar,mode) \ 236 do { \ 237 if (lockvar) \ 238 evthreadimpl_lock_unlock_(mode, lockvar); \ 239 } while (0) 240 241 /** Lock an event_base, if it is set up for locking. Acquires the lock 242 in the base structure whose field is named 'lockvar'. */ 243 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 244 EVLOCK_LOCK((base)->lockvar, 0); \ 245 } while (0) 246 247 /** Unlock an event_base, if it is set up for locking. */ 248 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 249 EVLOCK_UNLOCK((base)->lockvar, 0); \ 250 } while (0) 251 252 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 253 * locked and held by us. */ 254 #define EVLOCK_ASSERT_LOCKED(lock) \ 255 do { \ 256 if ((lock) && evthreadimpl_is_lock_debugging_enabled_()) { \ 257 EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ 258 } \ 259 } while (0) 260 261 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 262 * manage to get it. */ 263 static inline int EVLOCK_TRY_LOCK_(void *lock); 264 static inline int 265 EVLOCK_TRY_LOCK_(void *lock) 266 { 267 if (lock) { 268 int r = evthreadimpl_lock_lock_(EVTHREAD_TRY, lock); 269 return !r; 270 } else { 271 /* Locking is disabled either globally or for this thing; 272 * of course we count as having the lock. */ 273 return 1; 274 } 275 } 276 277 /** Allocate a new condition variable and store it in the void *, condvar */ 278 #define EVTHREAD_ALLOC_COND(condvar) \ 279 do { \ 280 (condvar) = evthreadimpl_cond_alloc_(0); \ 281 } while (0) 282 /** Deallocate and free a condition variable in condvar */ 283 #define EVTHREAD_FREE_COND(cond) \ 284 do { \ 285 if (cond) \ 286 evthreadimpl_cond_free_((cond)); \ 287 } while (0) 288 /** Signal one thread waiting on cond */ 289 #define EVTHREAD_COND_SIGNAL(cond) \ 290 ( (cond) ? evthreadimpl_cond_signal_((cond), 0) : 0 ) 291 /** Signal all threads waiting on cond */ 292 #define EVTHREAD_COND_BROADCAST(cond) \ 293 ( (cond) ? evthreadimpl_cond_signal_((cond), 1) : 0 ) 294 /** Wait until the condition 'cond' is signalled. Must be called while 295 * holding 'lock'. The lock will be released until the condition is 296 * signalled, at which point it will be acquired again. Returns 0 for 297 * success, -1 for failure. */ 298 #define EVTHREAD_COND_WAIT(cond, lock) \ 299 ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), NULL) : 0 ) 300 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 301 * on timeout. */ 302 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 303 ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), (tv)) : 0 ) 304 305 #define EVTHREAD_LOCKING_ENABLED() \ 306 (evthreadimpl_locking_enabled_()) 307 308 #else /* EVENT__DISABLE_THREAD_SUPPORT */ 309 310 #define EVTHREAD_GET_ID() 1 311 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ 312 #define EVTHREAD_FREE_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ 313 314 #define EVLOCK_LOCK(lockvar, mode) EVUTIL_NIL_STMT_ 315 #define EVLOCK_UNLOCK(lockvar, mode) EVUTIL_NIL_STMT_ 316 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ 317 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ 318 319 #define EVBASE_IN_THREAD(base) 1 320 #define EVBASE_NEED_NOTIFY(base) 0 321 #define EVBASE_ACQUIRE_LOCK(base, lock) EVUTIL_NIL_STMT_ 322 #define EVBASE_RELEASE_LOCK(base, lock) EVUTIL_NIL_STMT_ 323 #define EVLOCK_ASSERT_LOCKED(lock) EVUTIL_NIL_STMT_ 324 325 #define EVLOCK_TRY_LOCK_(lock) 1 326 327 #define EVTHREAD_ALLOC_COND(condvar) EVUTIL_NIL_STMT_ 328 #define EVTHREAD_FREE_COND(cond) EVUTIL_NIL_STMT_ 329 #define EVTHREAD_COND_SIGNAL(cond) EVUTIL_NIL_STMT_ 330 #define EVTHREAD_COND_BROADCAST(cond) EVUTIL_NIL_STMT_ 331 #define EVTHREAD_COND_WAIT(cond, lock) EVUTIL_NIL_STMT_ 332 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, howlong) EVUTIL_NIL_STMT_ 333 334 #define EVTHREAD_LOCKING_ENABLED() 0 335 336 #endif 337 338 /* This code is shared between both lock impls */ 339 #if ! defined(EVENT__DISABLE_THREAD_SUPPORT) 340 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 341 #define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ 342 do { \ 343 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 344 void *tmp = lockvar1; \ 345 lockvar1 = lockvar2; \ 346 lockvar2 = tmp; \ 347 } \ 348 } while (0) 349 350 /** Acquire both lock1 and lock2. Always allocates locks in the same order, 351 * so that two threads locking two locks with LOCK2 will not deadlock. */ 352 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) \ 353 do { \ 354 void *lock1_tmplock_ = (lock1); \ 355 void *lock2_tmplock_ = (lock2); \ 356 EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ 357 EVLOCK_LOCK(lock1_tmplock_,mode1); \ 358 if (lock2_tmplock_ != lock1_tmplock_) \ 359 EVLOCK_LOCK(lock2_tmplock_,mode2); \ 360 } while (0) 361 /** Release both lock1 and lock2. */ 362 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) \ 363 do { \ 364 void *lock1_tmplock_ = (lock1); \ 365 void *lock2_tmplock_ = (lock2); \ 366 EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ 367 if (lock2_tmplock_ != lock1_tmplock_) \ 368 EVLOCK_UNLOCK(lock2_tmplock_,mode2); \ 369 EVLOCK_UNLOCK(lock1_tmplock_,mode1); \ 370 } while (0) 371 372 EVENT2_EXPORT_SYMBOL 373 int evthread_is_debug_lock_held_(void *lock); 374 void *evthread_debug_get_real_lock_(void *lock); 375 376 void *evthread_setup_global_lock_(void *lock_, unsigned locktype, 377 int enable_locks); 378 379 #define EVTHREAD_SETUP_GLOBAL_LOCK(lockvar, locktype) \ 380 do { \ 381 lockvar = evthread_setup_global_lock_(lockvar, \ 382 (locktype), enable_locks); \ 383 if (!lockvar) { \ 384 event_warn("Couldn't allocate %s", #lockvar); \ 385 return -1; \ 386 } \ 387 } while (0); 388 389 int event_global_setup_locks_(const int enable_locks); 390 int evsig_global_setup_locks_(const int enable_locks); 391 int evutil_global_setup_locks_(const int enable_locks); 392 int evutil_secure_rng_global_setup_locks_(const int enable_locks); 393 394 /** Return current evthread_lock_callbacks */ 395 EVENT2_EXPORT_SYMBOL 396 struct evthread_lock_callbacks *evthread_get_lock_callbacks(void); 397 /** Return current evthread_condition_callbacks */ 398 struct evthread_condition_callbacks *evthread_get_condition_callbacks(void); 399 /** Disable locking for internal usage (like global shutdown) */ 400 void evthreadimpl_disable_lock_debugging_(void); 401 402 #endif 403 404 #ifdef __cplusplus 405 } 406 #endif 407 408 #endif /* EVTHREAD_INTERNAL_H_INCLUDED_ */ 409