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 ompi__evthread_lock_fns;
51 extern struct evthread_condition_callbacks ompi__evthread_cond_fns;
52 extern unsigned long (*ompi__evthread_id_fn)(void);
53 extern int ompi__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 (ompi__evthread_id_fn ? ompi__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 (ompi__evthread_id_fn == NULL || \
63 (base)->th_owner_id == ompi__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 (ompi__evthread_id_fn != NULL && \
70 (base)->running_loop && \
71 (base)->th_owner_id != ompi__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) = ompi__evthread_lock_fns.alloc ? \
77 ompi__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_ && ompi__evthread_lock_fns.free) \
84 ompi__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 ompi__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 ompi__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) && ompi__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 && ompi__evthread_lock_fns.lock) {
138 int r = ompi__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) = ompi__evthread_cond_fns.alloc_condition ? \
151 ompi__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 ompi__evthread_cond_fns.free_condition((cond)); \
158 } while (0)
159 /** Signal one thread waiting on cond */
160 #define EVTHREAD_COND_SIGNAL(cond) \
161 ( (cond) ? ompi__evthread_cond_fns.signal_condition((cond), 0) : 0 )
162 /** Signal all threads waiting on cond */
163 #define EVTHREAD_COND_BROADCAST(cond) \
164 ( (cond) ? ompi__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) ? ompi__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) ? ompi__evthread_cond_fns.wait_condition((cond), (lock), (tv)) : 0 )
175
176 /** True iff locking functions have been configured. */
177 #define EVTHREAD_LOCKING_ENABLED() \
178 (ompi__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_ */