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