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