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
EVLOCK_TRY_LOCK_(void * lock)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
EVLOCK_TRY_LOCK_(void * lock)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