1 /* $NetBSD: evthread-internal.h,v 1.2 2013/04/11 16:56:41 christos Exp $ */ 2 /* 3 * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef _EVTHREAD_INTERNAL_H_ 28 #define _EVTHREAD_INTERNAL_H_ 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 #include "event2/thread.h" 35 #include "event2/event-config.h" 36 #include "util-internal.h" 37 38 struct event_base; 39 40 #ifndef WIN32 41 /* On Windows, the way we currently make DLLs, it's not allowed for us to 42 * have shared global structures. Thus, we only do the direct-call-to-function 43 * code path if we know that the local shared library system supports it. 44 */ 45 #define EVTHREAD_EXPOSE_STRUCTS 46 #endif 47 48 #if ! defined(_EVENT_DISABLE_THREAD_SUPPORT) && defined(EVTHREAD_EXPOSE_STRUCTS) 49 /* Global function pointers to lock-related functions. NULL if locking isn't 50 enabled. */ 51 extern struct evthread_lock_callbacks _evthread_lock_fns; 52 extern struct evthread_condition_callbacks _evthread_cond_fns; 53 extern unsigned long (*_evthread_id_fn)(void); 54 extern int _evthread_lock_debugging_enabled; 55 56 /** Return the ID of the current thread, or 1 if threading isn't enabled. */ 57 #define EVTHREAD_GET_ID() \ 58 (_evthread_id_fn ? _evthread_id_fn() : 1) 59 60 /** Return true iff we're in the thread that is currently (or most recently) 61 * running a given event_base's loop. Requires lock. */ 62 #define EVBASE_IN_THREAD(base) \ 63 (_evthread_id_fn == NULL || \ 64 (base)->th_owner_id == _evthread_id_fn()) 65 66 /** Return true iff we need to notify the base's main thread about changes to 67 * its state, because it's currently running the main loop in another 68 * thread. Requires lock. */ 69 #define EVBASE_NEED_NOTIFY(base) \ 70 (_evthread_id_fn != NULL && \ 71 (base)->running_loop && \ 72 (base)->th_owner_id != _evthread_id_fn()) 73 74 /** Allocate a new lock, and store it in lockvar, a void*. Sets lockvar to 75 NULL if locking is not enabled. */ 76 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 77 ((lockvar) = _evthread_lock_fns.alloc ? \ 78 _evthread_lock_fns.alloc(locktype) : NULL) 79 80 /** Free a given lock, if it is present and locking is enabled. */ 81 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 82 do { \ 83 void *_lock_tmp_ = (lockvar); \ 84 if (_lock_tmp_ && _evthread_lock_fns.free) \ 85 _evthread_lock_fns.free(_lock_tmp_, (locktype)); \ 86 } while (/*CONSTCOND*/0) 87 88 /** Acquire a lock. */ 89 #define EVLOCK_LOCK(lockvar,mode) \ 90 do { \ 91 if (lockvar) \ 92 _evthread_lock_fns.lock(mode, lockvar); \ 93 } while (/*CONSTCOND*/0) 94 95 /** Release a lock */ 96 #define EVLOCK_UNLOCK(lockvar,mode) \ 97 do { \ 98 if (lockvar) \ 99 _evthread_lock_fns.unlock(mode, lockvar); \ 100 } while (/*CONSTCOND*/0) 101 102 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 103 #define _EVLOCK_SORTLOCKS(lockvar1, lockvar2) \ 104 do { \ 105 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 106 void *tmp = lockvar1; \ 107 lockvar1 = lockvar2; \ 108 lockvar2 = tmp; \ 109 } \ 110 } while (/*CONSTCOND*/0) 111 112 /** Lock an event_base, if it is set up for locking. Acquires the lock 113 in the base structure whose field is named 'lockvar'. */ 114 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 115 EVLOCK_LOCK((base)->lockvar, 0); \ 116 } while (/*CONSTCOND*/0) 117 118 /** Unlock an event_base, if it is set up for locking. */ 119 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 120 EVLOCK_UNLOCK((base)->lockvar, 0); \ 121 } while (/*CONSTCOND*/0) 122 123 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 124 * locked and held by us. */ 125 #define EVLOCK_ASSERT_LOCKED(lock) \ 126 do { \ 127 if ((lock) && _evthread_lock_debugging_enabled) { \ 128 EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \ 129 } \ 130 } while (/*CONSTCOND*/0) 131 132 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 133 * manage to get it. */ 134 static inline int EVLOCK_TRY_LOCK(void *lock); 135 static inline int 136 EVLOCK_TRY_LOCK(void *lock) 137 { 138 if (lock && _evthread_lock_fns.lock) { 139 int r = _evthread_lock_fns.lock(EVTHREAD_TRY, lock); 140 return !r; 141 } else { 142 /* Locking is disabled either globally or for this thing; 143 * of course we count as having the lock. */ 144 return 1; 145 } 146 } 147 148 /** Allocate a new condition variable and store it in the void *, condvar */ 149 #define EVTHREAD_ALLOC_COND(condvar) \ 150 do { \ 151 (condvar) = _evthread_cond_fns.alloc_condition ? \ 152 _evthread_cond_fns.alloc_condition(0) : NULL; \ 153 } while (/*CONSTCOND*/0) 154 /** Deallocate and free a condition variable in condvar */ 155 #define EVTHREAD_FREE_COND(cond) \ 156 do { \ 157 if (cond) \ 158 _evthread_cond_fns.free_condition((cond)); \ 159 } while (/*CONSTCOND*/0) 160 /** Signal one thread waiting on cond */ 161 #define EVTHREAD_COND_SIGNAL(cond) \ 162 ( (cond) ? _evthread_cond_fns.signal_condition((cond), 0) : 0 ) 163 /** Signal all threads waiting on cond */ 164 #define EVTHREAD_COND_BROADCAST(cond) \ 165 ( (cond) ? _evthread_cond_fns.signal_condition((cond), 1) : 0 ) 166 /** Wait until the condition 'cond' is signalled. Must be called while 167 * holding 'lock'. The lock will be released until the condition is 168 * signalled, at which point it will be acquired again. Returns 0 for 169 * success, -1 for failure. */ 170 #define EVTHREAD_COND_WAIT(cond, lock) \ 171 ( (cond) ? _evthread_cond_fns.wait_condition((cond), (lock), NULL) : 0 ) 172 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 173 * on timeout. */ 174 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 175 ( (cond) ? _evthread_cond_fns.wait_condition((cond), (lock), (tv)) : 0 ) 176 177 /** True iff locking functions have been configured. */ 178 #define EVTHREAD_LOCKING_ENABLED() \ 179 (_evthread_lock_fns.lock != NULL) 180 181 #elif ! defined(_EVENT_DISABLE_THREAD_SUPPORT) 182 183 unsigned long _evthreadimpl_get_id(void); 184 int _evthreadimpl_is_lock_debugging_enabled(void); 185 void *_evthreadimpl_lock_alloc(unsigned locktype); 186 void _evthreadimpl_lock_free(void *lock, unsigned locktype); 187 int _evthreadimpl_lock_lock(unsigned mode, void *lock); 188 int _evthreadimpl_lock_unlock(unsigned mode, void *lock); 189 void *_evthreadimpl_cond_alloc(unsigned condtype); 190 void _evthreadimpl_cond_free(void *cond); 191 int _evthreadimpl_cond_signal(void *cond, int broadcast); 192 int _evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv); 193 int _evthreadimpl_locking_enabled(void); 194 195 #define EVTHREAD_GET_ID() _evthreadimpl_get_id() 196 #define EVBASE_IN_THREAD(base) \ 197 ((base)->th_owner_id == _evthreadimpl_get_id()) 198 #define EVBASE_NEED_NOTIFY(base) \ 199 ((base)->running_loop && \ 200 ((base)->th_owner_id != _evthreadimpl_get_id())) 201 202 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 203 ((lockvar) = _evthreadimpl_lock_alloc(locktype)) 204 205 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 206 do { \ 207 void *_lock_tmp_ = (lockvar); \ 208 if (_lock_tmp_) \ 209 _evthreadimpl_lock_free(_lock_tmp_, (locktype)); \ 210 } while (/*CONSTCOND*/0) 211 212 /** Acquire a lock. */ 213 #define EVLOCK_LOCK(lockvar,mode) \ 214 do { \ 215 if (lockvar) \ 216 _evthreadimpl_lock_lock(mode, lockvar); \ 217 } while (/*CONSTCOND*/0) 218 219 /** Release a lock */ 220 #define EVLOCK_UNLOCK(lockvar,mode) \ 221 do { \ 222 if (lockvar) \ 223 _evthreadimpl_lock_unlock(mode, lockvar); \ 224 } while (/*CONSTCOND*/0) 225 226 /** Lock an event_base, if it is set up for locking. Acquires the lock 227 in the base structure whose field is named 'lockvar'. */ 228 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 229 EVLOCK_LOCK((base)->lockvar, 0); \ 230 } while (/*CONSTCOND*/0) 231 232 /** Unlock an event_base, if it is set up for locking. */ 233 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 234 EVLOCK_UNLOCK((base)->lockvar, 0); \ 235 } while (/*CONSTCOND*/0) 236 237 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 238 * locked and held by us. */ 239 #define EVLOCK_ASSERT_LOCKED(lock) \ 240 do { \ 241 if ((lock) && _evthreadimpl_is_lock_debugging_enabled()) { \ 242 EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \ 243 } \ 244 } while (/*CONSTCOND*/0) 245 246 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 247 * manage to get it. */ 248 static inline int EVLOCK_TRY_LOCK(void *lock); 249 static inline int 250 EVLOCK_TRY_LOCK(void *lock) 251 { 252 if (lock) { 253 int r = _evthreadimpl_lock_lock(EVTHREAD_TRY, lock); 254 return !r; 255 } else { 256 /* Locking is disabled either globally or for this thing; 257 * of course we count as having the lock. */ 258 return 1; 259 } 260 } 261 262 /** Allocate a new condition variable and store it in the void *, condvar */ 263 #define EVTHREAD_ALLOC_COND(condvar) \ 264 do { \ 265 (condvar) = _evthreadimpl_cond_alloc(0); \ 266 } while (/*CONSTCOND*/0) 267 /** Deallocate and free a condition variable in condvar */ 268 #define EVTHREAD_FREE_COND(cond) \ 269 do { \ 270 if (cond) \ 271 _evthreadimpl_cond_free((cond)); \ 272 } while (/*CONSTCOND*/0) 273 /** Signal one thread waiting on cond */ 274 #define EVTHREAD_COND_SIGNAL(cond) \ 275 ( (cond) ? _evthreadimpl_cond_signal((cond), 0) : 0 ) 276 /** Signal all threads waiting on cond */ 277 #define EVTHREAD_COND_BROADCAST(cond) \ 278 ( (cond) ? _evthreadimpl_cond_signal((cond), 1) : 0 ) 279 /** Wait until the condition 'cond' is signalled. Must be called while 280 * holding 'lock'. The lock will be released until the condition is 281 * signalled, at which point it will be acquired again. Returns 0 for 282 * success, -1 for failure. */ 283 #define EVTHREAD_COND_WAIT(cond, lock) \ 284 ( (cond) ? _evthreadimpl_cond_wait((cond), (lock), NULL) : 0 ) 285 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 286 * on timeout. */ 287 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 288 ( (cond) ? _evthreadimpl_cond_wait((cond), (lock), (tv)) : 0 ) 289 290 #define EVTHREAD_LOCKING_ENABLED() \ 291 (_evthreadimpl_locking_enabled()) 292 293 #else /* _EVENT_DISABLE_THREAD_SUPPORT */ 294 295 #define EVTHREAD_GET_ID() 1 296 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT 297 #define EVTHREAD_FREE_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT 298 299 #define EVLOCK_LOCK(lockvar, mode) _EVUTIL_NIL_STMT 300 #define EVLOCK_UNLOCK(lockvar, mode) _EVUTIL_NIL_STMT 301 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT 302 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT 303 304 #define EVBASE_IN_THREAD(base) 1 305 #define EVBASE_NEED_NOTIFY(base) 0 306 #define EVBASE_ACQUIRE_LOCK(base, lock) _EVUTIL_NIL_STMT 307 #define EVBASE_RELEASE_LOCK(base, lock) _EVUTIL_NIL_STMT 308 #define EVLOCK_ASSERT_LOCKED(lock) _EVUTIL_NIL_STMT 309 310 #define EVLOCK_TRY_LOCK(lock) 1 311 312 #define EVTHREAD_ALLOC_COND(condvar) _EVUTIL_NIL_STMT 313 #define EVTHREAD_FREE_COND(cond) _EVUTIL_NIL_STMT 314 #define EVTHREAD_COND_SIGNAL(cond) _EVUTIL_NIL_STMT 315 #define EVTHREAD_COND_BROADCAST(cond) _EVUTIL_NIL_STMT 316 #define EVTHREAD_COND_WAIT(cond, lock) _EVUTIL_NIL_STMT 317 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, howlong) _EVUTIL_NIL_STMT 318 319 #define EVTHREAD_LOCKING_ENABLED() 0 320 321 #endif 322 323 /* This code is shared between both lock impls */ 324 #if ! defined(_EVENT_DISABLE_THREAD_SUPPORT) 325 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 326 #define _EVLOCK_SORTLOCKS(lockvar1, lockvar2) \ 327 do { \ 328 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 329 void *tmp = lockvar1; \ 330 lockvar1 = lockvar2; \ 331 lockvar2 = tmp; \ 332 } \ 333 } while (/*CONSTCOND*/0) 334 335 /** Acquire both lock1 and lock2. Always allocates locks in the same order, 336 * so that two threads locking two locks with LOCK2 will not deadlock. */ 337 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) \ 338 do { \ 339 void *_lock1_tmplock = (lock1); \ 340 void *_lock2_tmplock = (lock2); \ 341 _EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock); \ 342 EVLOCK_LOCK(_lock1_tmplock,mode1); \ 343 if (_lock2_tmplock != _lock1_tmplock) \ 344 EVLOCK_LOCK(_lock2_tmplock,mode2); \ 345 } while (/*CONSTCOND*/0) 346 /** Release both lock1 and lock2. */ 347 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) \ 348 do { \ 349 void *_lock1_tmplock = (lock1); \ 350 void *_lock2_tmplock = (lock2); \ 351 _EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock); \ 352 if (_lock2_tmplock != _lock1_tmplock) \ 353 EVLOCK_UNLOCK(_lock2_tmplock,mode2); \ 354 EVLOCK_UNLOCK(_lock1_tmplock,mode1); \ 355 } while (/*CONSTCOND*/0) 356 357 int _evthread_is_debug_lock_held(void *lock); 358 void *_evthread_debug_get_real_lock(void *lock); 359 360 void *evthread_setup_global_lock_(void *lock_, unsigned locktype, 361 int enable_locks); 362 363 #define EVTHREAD_SETUP_GLOBAL_LOCK(lockvar, locktype) \ 364 do { \ 365 lockvar = evthread_setup_global_lock_(lockvar, \ 366 (locktype), enable_locks); \ 367 if (!lockvar) { \ 368 event_warn("Couldn't allocate %s", #lockvar); \ 369 return -1; \ 370 } \ 371 } while (/*CONSTCOND*/0); 372 373 int event_global_setup_locks_(const int enable_locks); 374 int evsig_global_setup_locks_(const int enable_locks); 375 int evutil_secure_rng_global_setup_locks_(const int enable_locks); 376 377 #endif 378 379 #ifdef __cplusplus 380 } 381 #endif 382 383 #endif /* _EVTHREAD_INTERNAL_H_ */ 384