1 /* $NetBSD: evthread-internal.h,v 1.1.1.1 2013/12/27 23:31:24 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 #ifndef _WIN32 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 extern struct evthread_lock_callbacks evthread_lock_fns_; 55 extern struct evthread_condition_callbacks evthread_cond_fns_; 56 extern unsigned long (*evthread_id_fn_)(void); 57 extern int evthread_lock_debugging_enabled_; 58 59 /** Return the ID of the current thread, or 1 if threading isn't enabled. */ 60 #define EVTHREAD_GET_ID() \ 61 (evthread_id_fn_ ? evthread_id_fn_() : 1) 62 63 /** Return true iff we're in the thread that is currently (or most recently) 64 * running a given event_base's loop. Requires lock. */ 65 #define EVBASE_IN_THREAD(base) \ 66 (evthread_id_fn_ == NULL || \ 67 (base)->th_owner_id == evthread_id_fn_()) 68 69 /** Return true iff we need to notify the base's main thread about changes to 70 * its state, because it's currently running the main loop in another 71 * thread. Requires lock. */ 72 #define EVBASE_NEED_NOTIFY(base) \ 73 (evthread_id_fn_ != NULL && \ 74 (base)->running_loop && \ 75 (base)->th_owner_id != evthread_id_fn_()) 76 77 /** Allocate a new lock, and store it in lockvar, a void*. Sets lockvar to 78 NULL if locking is not enabled. */ 79 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 80 ((lockvar) = evthread_lock_fns_.alloc ? \ 81 evthread_lock_fns_.alloc(locktype) : NULL) 82 83 /** Free a given lock, if it is present and locking is enabled. */ 84 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 85 do { \ 86 void *lock_tmp_ = (lockvar); \ 87 if (lock_tmp_ && evthread_lock_fns_.free) \ 88 evthread_lock_fns_.free(lock_tmp_, (locktype)); \ 89 } while (0) 90 91 /** Acquire a lock. */ 92 #define EVLOCK_LOCK(lockvar,mode) \ 93 do { \ 94 if (lockvar) \ 95 evthread_lock_fns_.lock(mode, lockvar); \ 96 } while (0) 97 98 /** Release a lock */ 99 #define EVLOCK_UNLOCK(lockvar,mode) \ 100 do { \ 101 if (lockvar) \ 102 evthread_lock_fns_.unlock(mode, lockvar); \ 103 } while (0) 104 105 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 106 #define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ 107 do { \ 108 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 109 void *tmp = lockvar1; \ 110 lockvar1 = lockvar2; \ 111 lockvar2 = tmp; \ 112 } \ 113 } while (0) 114 115 /** Lock an event_base, if it is set up for locking. Acquires the lock 116 in the base structure whose field is named 'lockvar'. */ 117 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 118 EVLOCK_LOCK((base)->lockvar, 0); \ 119 } while (0) 120 121 /** Unlock an event_base, if it is set up for locking. */ 122 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 123 EVLOCK_UNLOCK((base)->lockvar, 0); \ 124 } while (0) 125 126 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 127 * locked and held by us. */ 128 #define EVLOCK_ASSERT_LOCKED(lock) \ 129 do { \ 130 if ((lock) && evthread_lock_debugging_enabled_) { \ 131 EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ 132 } \ 133 } while (0) 134 135 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 136 * manage to get it. */ 137 static inline int EVLOCK_TRY_LOCK_(void *lock); 138 static inline int 139 EVLOCK_TRY_LOCK_(void *lock) 140 { 141 if (lock && evthread_lock_fns_.lock) { 142 int r = evthread_lock_fns_.lock(EVTHREAD_TRY, lock); 143 return !r; 144 } else { 145 /* Locking is disabled either globally or for this thing; 146 * of course we count as having the lock. */ 147 return 1; 148 } 149 } 150 151 /** Allocate a new condition variable and store it in the void *, condvar */ 152 #define EVTHREAD_ALLOC_COND(condvar) \ 153 do { \ 154 (condvar) = evthread_cond_fns_.alloc_condition ? \ 155 evthread_cond_fns_.alloc_condition(0) : NULL; \ 156 } while (0) 157 /** Deallocate and free a condition variable in condvar */ 158 #define EVTHREAD_FREE_COND(cond) \ 159 do { \ 160 if (cond) \ 161 evthread_cond_fns_.free_condition((cond)); \ 162 } while (0) 163 /** Signal one thread waiting on cond */ 164 #define EVTHREAD_COND_SIGNAL(cond) \ 165 ( (cond) ? evthread_cond_fns_.signal_condition((cond), 0) : 0 ) 166 /** Signal all threads waiting on cond */ 167 #define EVTHREAD_COND_BROADCAST(cond) \ 168 ( (cond) ? evthread_cond_fns_.signal_condition((cond), 1) : 0 ) 169 /** Wait until the condition 'cond' is signalled. Must be called while 170 * holding 'lock'. The lock will be released until the condition is 171 * signalled, at which point it will be acquired again. Returns 0 for 172 * success, -1 for failure. */ 173 #define EVTHREAD_COND_WAIT(cond, lock) \ 174 ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), NULL) : 0 ) 175 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 176 * on timeout. */ 177 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 178 ( (cond) ? evthread_cond_fns_.wait_condition((cond), (lock), (tv)) : 0 ) 179 180 /** True iff locking functions have been configured. */ 181 #define EVTHREAD_LOCKING_ENABLED() \ 182 (evthread_lock_fns_.lock != NULL) 183 184 #elif ! defined(EVENT__DISABLE_THREAD_SUPPORT) 185 186 unsigned long evthreadimpl_get_id_(void); 187 int evthreadimpl_is_lock_debugging_enabled_(void); 188 void *evthreadimpl_lock_alloc_(unsigned locktype); 189 void evthreadimpl_lock_free_(void *lock, unsigned locktype); 190 int evthreadimpl_lock_lock_(unsigned mode, void *lock); 191 int evthreadimpl_lock_unlock_(unsigned mode, void *lock); 192 void *evthreadimpl_cond_alloc_(unsigned condtype); 193 void evthreadimpl_cond_free_(void *cond); 194 int evthreadimpl_cond_signal_(void *cond, int broadcast); 195 int evthreadimpl_cond_wait_(void *cond, void *lock, const struct timeval *tv); 196 int evthreadimpl_locking_enabled_(void); 197 198 #define EVTHREAD_GET_ID() evthreadimpl_get_id_() 199 #define EVBASE_IN_THREAD(base) \ 200 ((base)->th_owner_id == evthreadimpl_get_id_()) 201 #define EVBASE_NEED_NOTIFY(base) \ 202 ((base)->running_loop && \ 203 ((base)->th_owner_id != evthreadimpl_get_id_())) 204 205 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \ 206 ((lockvar) = evthreadimpl_lock_alloc_(locktype)) 207 208 #define EVTHREAD_FREE_LOCK(lockvar, locktype) \ 209 do { \ 210 void *lock_tmp_ = (lockvar); \ 211 if (lock_tmp_) \ 212 evthreadimpl_lock_free_(lock_tmp_, (locktype)); \ 213 } while (0) 214 215 /** Acquire a lock. */ 216 #define EVLOCK_LOCK(lockvar,mode) \ 217 do { \ 218 if (lockvar) \ 219 evthreadimpl_lock_lock_(mode, lockvar); \ 220 } while (0) 221 222 /** Release a lock */ 223 #define EVLOCK_UNLOCK(lockvar,mode) \ 224 do { \ 225 if (lockvar) \ 226 evthreadimpl_lock_unlock_(mode, lockvar); \ 227 } while (0) 228 229 /** Lock an event_base, if it is set up for locking. Acquires the lock 230 in the base structure whose field is named 'lockvar'. */ 231 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \ 232 EVLOCK_LOCK((base)->lockvar, 0); \ 233 } while (0) 234 235 /** Unlock an event_base, if it is set up for locking. */ 236 #define EVBASE_RELEASE_LOCK(base, lockvar) do { \ 237 EVLOCK_UNLOCK((base)->lockvar, 0); \ 238 } while (0) 239 240 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is 241 * locked and held by us. */ 242 #define EVLOCK_ASSERT_LOCKED(lock) \ 243 do { \ 244 if ((lock) && evthreadimpl_is_lock_debugging_enabled_()) { \ 245 EVUTIL_ASSERT(evthread_is_debug_lock_held_(lock)); \ 246 } \ 247 } while (0) 248 249 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we 250 * manage to get it. */ 251 static inline int EVLOCK_TRY_LOCK_(void *lock); 252 static inline int 253 EVLOCK_TRY_LOCK_(void *lock) 254 { 255 if (lock) { 256 int r = evthreadimpl_lock_lock_(EVTHREAD_TRY, lock); 257 return !r; 258 } else { 259 /* Locking is disabled either globally or for this thing; 260 * of course we count as having the lock. */ 261 return 1; 262 } 263 } 264 265 /** Allocate a new condition variable and store it in the void *, condvar */ 266 #define EVTHREAD_ALLOC_COND(condvar) \ 267 do { \ 268 (condvar) = evthreadimpl_cond_alloc_(0); \ 269 } while (0) 270 /** Deallocate and free a condition variable in condvar */ 271 #define EVTHREAD_FREE_COND(cond) \ 272 do { \ 273 if (cond) \ 274 evthreadimpl_cond_free_((cond)); \ 275 } while (0) 276 /** Signal one thread waiting on cond */ 277 #define EVTHREAD_COND_SIGNAL(cond) \ 278 ( (cond) ? evthreadimpl_cond_signal_((cond), 0) : 0 ) 279 /** Signal all threads waiting on cond */ 280 #define EVTHREAD_COND_BROADCAST(cond) \ 281 ( (cond) ? evthreadimpl_cond_signal_((cond), 1) : 0 ) 282 /** Wait until the condition 'cond' is signalled. Must be called while 283 * holding 'lock'. The lock will be released until the condition is 284 * signalled, at which point it will be acquired again. Returns 0 for 285 * success, -1 for failure. */ 286 #define EVTHREAD_COND_WAIT(cond, lock) \ 287 ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), NULL) : 0 ) 288 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed. Returns 1 289 * on timeout. */ 290 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv) \ 291 ( (cond) ? evthreadimpl_cond_wait_((cond), (lock), (tv)) : 0 ) 292 293 #define EVTHREAD_LOCKING_ENABLED() \ 294 (evthreadimpl_locking_enabled_()) 295 296 #else /* EVENT__DISABLE_THREAD_SUPPORT */ 297 298 #define EVTHREAD_GET_ID() 1 299 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ 300 #define EVTHREAD_FREE_LOCK(lockvar, locktype) EVUTIL_NIL_STMT_ 301 302 #define EVLOCK_LOCK(lockvar, mode) EVUTIL_NIL_STMT_ 303 #define EVLOCK_UNLOCK(lockvar, mode) EVUTIL_NIL_STMT_ 304 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ 305 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) EVUTIL_NIL_STMT_ 306 307 #define EVBASE_IN_THREAD(base) 1 308 #define EVBASE_NEED_NOTIFY(base) 0 309 #define EVBASE_ACQUIRE_LOCK(base, lock) EVUTIL_NIL_STMT_ 310 #define EVBASE_RELEASE_LOCK(base, lock) EVUTIL_NIL_STMT_ 311 #define EVLOCK_ASSERT_LOCKED(lock) EVUTIL_NIL_STMT_ 312 313 #define EVLOCK_TRY_LOCK_(lock) 1 314 315 #define EVTHREAD_ALLOC_COND(condvar) EVUTIL_NIL_STMT_ 316 #define EVTHREAD_FREE_COND(cond) EVUTIL_NIL_STMT_ 317 #define EVTHREAD_COND_SIGNAL(cond) EVUTIL_NIL_STMT_ 318 #define EVTHREAD_COND_BROADCAST(cond) EVUTIL_NIL_STMT_ 319 #define EVTHREAD_COND_WAIT(cond, lock) EVUTIL_NIL_STMT_ 320 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, howlong) EVUTIL_NIL_STMT_ 321 322 #define EVTHREAD_LOCKING_ENABLED() 0 323 324 #endif 325 326 /* This code is shared between both lock impls */ 327 #if ! defined(EVENT__DISABLE_THREAD_SUPPORT) 328 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */ 329 #define EVLOCK_SORTLOCKS_(lockvar1, lockvar2) \ 330 do { \ 331 if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \ 332 void *tmp = lockvar1; \ 333 lockvar1 = lockvar2; \ 334 lockvar2 = tmp; \ 335 } \ 336 } while (0) 337 338 /** Acquire both lock1 and lock2. Always allocates locks in the same order, 339 * so that two threads locking two locks with LOCK2 will not deadlock. */ 340 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) \ 341 do { \ 342 void *lock1_tmplock_ = (lock1); \ 343 void *lock2_tmplock_ = (lock2); \ 344 EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ 345 EVLOCK_LOCK(lock1_tmplock_,mode1); \ 346 if (lock2_tmplock_ != lock1_tmplock_) \ 347 EVLOCK_LOCK(lock2_tmplock_,mode2); \ 348 } while (0) 349 /** Release both lock1 and lock2. */ 350 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) \ 351 do { \ 352 void *lock1_tmplock_ = (lock1); \ 353 void *lock2_tmplock_ = (lock2); \ 354 EVLOCK_SORTLOCKS_(lock1_tmplock_,lock2_tmplock_); \ 355 if (lock2_tmplock_ != lock1_tmplock_) \ 356 EVLOCK_UNLOCK(lock2_tmplock_,mode2); \ 357 EVLOCK_UNLOCK(lock1_tmplock_,mode1); \ 358 } while (0) 359 360 int evthread_is_debug_lock_held_(void *lock); 361 void *evthread_debug_get_real_lock_(void *lock); 362 363 void *evthread_setup_global_lock_(void *lock_, unsigned locktype, 364 int enable_locks); 365 366 #define EVTHREAD_SETUP_GLOBAL_LOCK(lockvar, locktype) \ 367 do { \ 368 lockvar = evthread_setup_global_lock_(lockvar, \ 369 (locktype), enable_locks); \ 370 if (!lockvar) { \ 371 event_warn("Couldn't allocate %s", #lockvar); \ 372 return -1; \ 373 } \ 374 } while (0); 375 376 int event_global_setup_locks_(const int enable_locks); 377 int evsig_global_setup_locks_(const int enable_locks); 378 int evutil_global_setup_locks_(const int enable_locks); 379 int evutil_secure_rng_global_setup_locks_(const int enable_locks); 380 381 #endif 382 383 #ifdef __cplusplus 384 } 385 #endif 386 387 #endif /* EVTHREAD_INTERNAL_H_INCLUDED_ */ 388