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