event-internal.h (17412B)
1 /* 2 * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu> 3 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef EVENT_INTERNAL_H_INCLUDED_ 28 #define EVENT_INTERNAL_H_INCLUDED_ 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 #include "event2/event-config.h" 35 #include "evconfig-private.h" 36 37 #include <time.h> 38 #include <sys/queue.h> 39 #include "event2/event_struct.h" 40 #include "minheap-internal.h" 41 #include "evsignal-internal.h" 42 #include "mm-internal.h" 43 #include "defer-internal.h" 44 45 /* map union members back */ 46 47 /* mutually exclusive */ 48 #define ev_signal_next ev_.ev_signal.ev_signal_next 49 #define ev_io_next ev_.ev_io.ev_io_next 50 #define ev_io_timeout ev_.ev_io.ev_timeout 51 52 /* used only by signals */ 53 #define ev_ncalls ev_.ev_signal.ev_ncalls 54 #define ev_pncalls ev_.ev_signal.ev_pncalls 55 56 #define ev_pri ev_evcallback.evcb_pri 57 #define ev_flags ev_evcallback.evcb_flags 58 #define ev_closure ev_evcallback.evcb_closure 59 #define ev_callback ev_evcallback.evcb_cb_union.evcb_callback 60 #define ev_arg ev_evcallback.evcb_arg 61 62 /** @name Event closure codes 63 64 Possible values for evcb_closure in struct event_callback 65 66 @{ 67 */ 68 /** A regular event. Uses the evcb_callback callback */ 69 #define EV_CLOSURE_EVENT 0 70 /** A signal event. Uses the evcb_callback callback */ 71 #define EV_CLOSURE_EVENT_SIGNAL 1 72 /** A persistent non-signal event. Uses the evcb_callback callback */ 73 #define EV_CLOSURE_EVENT_PERSIST 2 74 /** A simple callback. Uses the evcb_selfcb callback. */ 75 #define EV_CLOSURE_CB_SELF 3 76 /** A finalizing callback. Uses the evcb_cbfinalize callback. */ 77 #define EV_CLOSURE_CB_FINALIZE 4 78 /** A finalizing event. Uses the evcb_evfinalize callback. */ 79 #define EV_CLOSURE_EVENT_FINALIZE 5 80 /** A finalizing event that should get freed after. Uses the evcb_evfinalize 81 * callback. */ 82 #define EV_CLOSURE_EVENT_FINALIZE_FREE 6 83 /** @} */ 84 85 /** Structure to define the backend of a given event_base. */ 86 struct eventop { 87 /** The name of this backend. */ 88 const char *name; 89 /** Function to set up an event_base to use this backend. It should 90 * create a new structure holding whatever information is needed to 91 * run the backend, and return it. The returned pointer will get 92 * stored by event_init into the event_base.evbase field. On failure, 93 * this function should return NULL. */ 94 void *(*init)(struct event_base *); 95 /** Enable reading/writing on a given fd or signal. 'events' will be 96 * the events that we're trying to enable: one or more of EV_READ, 97 * EV_WRITE, EV_SIGNAL, and EV_ET. 'old' will be those events that 98 * were enabled on this fd previously. 'fdinfo' will be a structure 99 * associated with the fd by the evmap; its size is defined by the 100 * fdinfo field below. It will be set to 0 the first time the fd is 101 * added. The function should return 0 on success and -1 on error. 102 */ 103 int (*add)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo); 104 /** As "add", except 'events' contains the events we mean to disable. */ 105 int (*del)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo); 106 /** Function to implement the core of an event loop. It must see which 107 added events are ready, and cause event_active to be called for each 108 active event (usually via event_io_active or such). It should 109 return 0 on success and -1 on error. 110 */ 111 int (*dispatch)(struct event_base *, struct timeval *); 112 /** Function to clean up and free our data from the event_base. */ 113 void (*dealloc)(struct event_base *); 114 /** Flag: set if we need to reinitialize the event base after we fork. 115 */ 116 int need_reinit; 117 /** Bit-array of supported event_method_features that this backend can 118 * provide. */ 119 enum event_method_feature features; 120 /** Length of the extra information we should record for each fd that 121 has one or more active events. This information is recorded 122 as part of the evmap entry for each fd, and passed as an argument 123 to the add and del functions above. 124 */ 125 size_t fdinfo_len; 126 }; 127 128 #ifdef _WIN32 129 /* If we're on win32, then file descriptors are not nice low densely packed 130 integers. Instead, they are pointer-like windows handles, and we want to 131 use a hashtable instead of an array to map fds to events. 132 */ 133 #define EVMAP_USE_HT 134 #endif 135 136 /* #define HT_CACHE_HASH_VALS */ 137 138 #ifdef EVMAP_USE_HT 139 #define HT_NO_CACHE_HASH_VALUES 140 #include "ht-internal.h" 141 struct event_map_entry; 142 HT_HEAD(event_io_map, event_map_entry); 143 #else 144 #define event_io_map event_signal_map 145 #endif 146 147 /* Used to map signal numbers to a list of events. If EVMAP_USE_HT is not 148 defined, this structure is also used as event_io_map, which maps fds to a 149 list of events. 150 */ 151 struct event_signal_map { 152 /* An array of evmap_io * or of evmap_signal *; empty entries are 153 * set to NULL. */ 154 void **entries; 155 /* The number of entries available in entries */ 156 int nentries; 157 }; 158 159 /* A list of events waiting on a given 'common' timeout value. Ordinarily, 160 * events waiting for a timeout wait on a minheap. Sometimes, however, a 161 * queue can be faster. 162 **/ 163 struct common_timeout_list { 164 /* List of events currently waiting in the queue. */ 165 struct event_list events; 166 /* 'magic' timeval used to indicate the duration of events in this 167 * queue. */ 168 struct timeval duration; 169 /* Event that triggers whenever one of the events in the queue is 170 * ready to activate */ 171 struct event timeout_event; 172 /* The event_base that this timeout list is part of */ 173 struct event_base *base; 174 }; 175 176 /** Mask used to get the real tv_usec value from a common timeout. */ 177 #define COMMON_TIMEOUT_MICROSECONDS_MASK 0x000fffff 178 179 struct event_change; 180 181 /* List of 'changes' since the last call to eventop.dispatch. Only maintained 182 * if the backend is using changesets. */ 183 struct event_changelist { 184 struct event_change *changes; 185 int n_changes; 186 int changes_size; 187 }; 188 189 #ifndef EVENT__DISABLE_DEBUG_MODE 190 /* Global internal flag: set to one if debug mode is on. */ 191 extern int event_debug_mode_on_; 192 #define EVENT_DEBUG_MODE_IS_ON() (event_debug_mode_on_) 193 #else 194 #define EVENT_DEBUG_MODE_IS_ON() (0) 195 #endif 196 197 TAILQ_HEAD(evcallback_list, event_callback); 198 199 /* Sets up an event for processing once */ 200 struct event_once { 201 LIST_ENTRY(event_once) next_once; 202 struct event ev; 203 204 void (*cb)(evutil_socket_t, short, void *); 205 void *arg; 206 }; 207 208 struct event_base { 209 /** Function pointers and other data to describe this event_base's 210 * backend. */ 211 const struct eventop *evsel; 212 /** Pointer to backend-specific data. */ 213 void *evbase; 214 215 /** List of changes to tell backend about at next dispatch. Only used 216 * by the O(1) backends. */ 217 struct event_changelist changelist; 218 219 /** Function pointers used to describe the backend that this event_base 220 * uses for signals */ 221 const struct eventop *evsigsel; 222 /** Data to implement the common signal handler code. */ 223 struct evsig_info sig; 224 225 /** Number of virtual events */ 226 int virtual_event_count; 227 /** Maximum number of virtual events active */ 228 int virtual_event_count_max; 229 /** Number of total events added to this event_base */ 230 int event_count; 231 /** Maximum number of total events added to this event_base */ 232 int event_count_max; 233 /** Number of total events active in this event_base */ 234 int event_count_active; 235 /** Maximum number of total events active in this event_base */ 236 int event_count_active_max; 237 238 /** Set if we should terminate the loop once we're done processing 239 * events. */ 240 int event_gotterm; 241 /** Set if we should terminate the loop immediately */ 242 int event_break; 243 /** Set if we should start a new instance of the loop immediately. */ 244 int event_continue; 245 246 /** The currently running priority of events */ 247 int event_running_priority; 248 249 /** Set if we're running the event_base_loop function, to prevent 250 * reentrant invocation. */ 251 int running_loop; 252 253 /** Set to the number of deferred_cbs we've made 'active' in the 254 * loop. This is a hack to prevent starvation; it would be smarter 255 * to just use event_config_set_max_dispatch_interval's max_callbacks 256 * feature */ 257 int n_deferreds_queued; 258 259 /* Active event management. */ 260 /** An array of nactivequeues queues for active event_callbacks (ones 261 * that have triggered, and whose callbacks need to be called). Low 262 * priority numbers are more important, and stall higher ones. 263 */ 264 struct evcallback_list *activequeues; 265 /** The length of the activequeues array */ 266 int nactivequeues; 267 /** A list of event_callbacks that should become active the next time 268 * we process events, but not this time. */ 269 struct evcallback_list active_later_queue; 270 271 /* common timeout logic */ 272 273 /** An array of common_timeout_list* for all of the common timeout 274 * values we know. */ 275 struct common_timeout_list **common_timeout_queues; 276 /** The number of entries used in common_timeout_queues */ 277 int n_common_timeouts; 278 /** The total size of common_timeout_queues. */ 279 int n_common_timeouts_allocated; 280 281 /** Mapping from file descriptors to enabled (added) events */ 282 struct event_io_map io; 283 284 /** Mapping from signal numbers to enabled (added) events. */ 285 struct event_signal_map sigmap; 286 287 /** Priority queue of events with timeouts. */ 288 struct min_heap timeheap; 289 290 /** Stored timeval: used to avoid calling gettimeofday/clock_gettime 291 * too often. */ 292 struct timeval tv_cache; 293 294 struct evutil_monotonic_timer monotonic_timer; 295 296 /** Difference between internal time (maybe from clock_gettime) and 297 * gettimeofday. */ 298 struct timeval tv_clock_diff; 299 /** Second in which we last updated tv_clock_diff, in monotonic time. */ 300 time_t last_updated_clock_diff; 301 302 #ifndef EVENT__DISABLE_THREAD_SUPPORT 303 /* threading support */ 304 /** The thread currently running the event_loop for this base */ 305 unsigned long th_owner_id; 306 /** A lock to prevent conflicting accesses to this event_base */ 307 void *th_base_lock; 308 /** A condition that gets signalled when we're done processing an 309 * event with waiters on it. */ 310 void *current_event_cond; 311 /** Number of threads blocking on current_event_cond. */ 312 int current_event_waiters; 313 #endif 314 /** The event whose callback is executing right now */ 315 struct event_callback *current_event; 316 317 #ifdef _WIN32 318 /** IOCP support structure, if IOCP is enabled. */ 319 struct event_iocp_port *iocp; 320 #endif 321 322 /** Flags that this base was configured with */ 323 enum event_base_config_flag flags; 324 325 struct timeval max_dispatch_time; 326 int max_dispatch_callbacks; 327 int limit_callbacks_after_prio; 328 329 /* Notify main thread to wake up break, etc. */ 330 /** True if the base already has a pending notify, and we don't need 331 * to add any more. */ 332 int is_notify_pending; 333 /** A socketpair used by some th_notify functions to wake up the main 334 * thread. */ 335 evutil_socket_t th_notify_fd[2]; 336 /** An event used by some th_notify functions to wake up the main 337 * thread. */ 338 struct event th_notify; 339 /** A function used to wake up the main thread from another thread. */ 340 int (*th_notify_fn)(struct event_base *base); 341 342 /** Saved seed for weak random number generator. Some backends use 343 * this to produce fairness among sockets. Protected by th_base_lock. */ 344 struct evutil_weakrand_state weakrand_seed; 345 346 /** List of event_onces that have not yet fired. */ 347 LIST_HEAD(once_event_list, event_once) once_events; 348 349 }; 350 351 struct event_config_entry { 352 TAILQ_ENTRY(event_config_entry) next; 353 354 const char *avoid_method; 355 }; 356 357 /** Internal structure: describes the configuration we want for an event_base 358 * that we're about to allocate. */ 359 struct event_config { 360 TAILQ_HEAD(event_configq, event_config_entry) entries; 361 362 int n_cpus_hint; 363 struct timeval max_dispatch_interval; 364 int max_dispatch_callbacks; 365 int limit_callbacks_after_prio; 366 enum event_method_feature require_features; 367 enum event_base_config_flag flags; 368 }; 369 370 /* Internal use only: Functions that might be missing from <sys/queue.h> */ 371 #ifndef LIST_END 372 #define LIST_END(head) NULL 373 #endif 374 375 #ifndef TAILQ_FIRST 376 #define TAILQ_FIRST(head) ((head)->tqh_first) 377 #endif 378 #ifndef TAILQ_END 379 #define TAILQ_END(head) NULL 380 #endif 381 #ifndef TAILQ_NEXT 382 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 383 #endif 384 385 #ifndef TAILQ_FOREACH 386 #define TAILQ_FOREACH(var, head, field) \ 387 for ((var) = TAILQ_FIRST(head); \ 388 (var) != TAILQ_END(head); \ 389 (var) = TAILQ_NEXT(var, field)) 390 #endif 391 392 #ifndef TAILQ_INSERT_BEFORE 393 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 394 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 395 (elm)->field.tqe_next = (listelm); \ 396 *(listelm)->field.tqe_prev = (elm); \ 397 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 398 } while (0) 399 #endif 400 401 #define N_ACTIVE_CALLBACKS(base) \ 402 ((base)->event_count_active) 403 404 int evsig_set_handler_(struct event_base *base, int evsignal, 405 void (*fn)(int)); 406 int evsig_restore_handler_(struct event_base *base, int evsignal); 407 408 int event_add_nolock_(struct event *ev, 409 const struct timeval *tv, int tv_is_absolute); 410 /** Argument for event_del_nolock_. Tells event_del not to block on the event 411 * if it's running in another thread. */ 412 #define EVENT_DEL_NOBLOCK 0 413 /** Argument for event_del_nolock_. Tells event_del to block on the event 414 * if it's running in another thread, regardless of its value for EV_FINALIZE 415 */ 416 #define EVENT_DEL_BLOCK 1 417 /** Argument for event_del_nolock_. Tells event_del to block on the event 418 * if it is running in another thread and it doesn't have EV_FINALIZE set. 419 */ 420 #define EVENT_DEL_AUTOBLOCK 2 421 /** Argument for event_del_nolock_. Tells event_del to proceed even if the 422 * event is set up for finalization rather for regular use.*/ 423 #define EVENT_DEL_EVEN_IF_FINALIZING 3 424 int event_del_nolock_(struct event *ev, int blocking); 425 int event_remove_timer_nolock_(struct event *ev); 426 427 void event_active_nolock_(struct event *ev, int res, short count); 428 EVENT2_EXPORT_SYMBOL 429 int event_callback_activate_(struct event_base *, struct event_callback *); 430 int event_callback_activate_nolock_(struct event_base *, struct event_callback *); 431 int event_callback_cancel_(struct event_base *base, 432 struct event_callback *evcb); 433 434 void event_callback_finalize_nolock_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *)); 435 EVENT2_EXPORT_SYMBOL 436 void event_callback_finalize_(struct event_base *base, unsigned flags, struct event_callback *evcb, void (*cb)(struct event_callback *, void *)); 437 int event_callback_finalize_many_(struct event_base *base, int n_cbs, struct event_callback **evcb, void (*cb)(struct event_callback *, void *)); 438 439 440 EVENT2_EXPORT_SYMBOL 441 void event_active_later_(struct event *ev, int res); 442 void event_active_later_nolock_(struct event *ev, int res); 443 int event_callback_activate_later_nolock_(struct event_base *base, 444 struct event_callback *evcb); 445 int event_callback_cancel_nolock_(struct event_base *base, 446 struct event_callback *evcb, int even_if_finalizing); 447 void event_callback_init_(struct event_base *base, 448 struct event_callback *cb); 449 450 /* FIXME document. */ 451 EVENT2_EXPORT_SYMBOL 452 void event_base_add_virtual_(struct event_base *base); 453 void event_base_del_virtual_(struct event_base *base); 454 455 /** For debugging: unless assertions are disabled, verify the referential 456 integrity of the internal data structures of 'base'. This operation can 457 be expensive. 458 459 Returns on success; aborts on failure. 460 */ 461 EVENT2_EXPORT_SYMBOL 462 void event_base_assert_ok_(struct event_base *base); 463 void event_base_assert_ok_nolock_(struct event_base *base); 464 465 466 /* Helper function: Call 'fn' exactly once every inserted or active event in 467 * the event_base 'base'. 468 * 469 * If fn returns 0, continue on to the next event. Otherwise, return the same 470 * value that fn returned. 471 * 472 * Requires that 'base' be locked. 473 */ 474 int event_base_foreach_event_nolock_(struct event_base *base, 475 event_base_foreach_event_cb cb, void *arg); 476 477 /* Cleanup function to reset debug mode during shutdown. 478 * 479 * Calling this function doesn't mean it'll be possible to re-enable 480 * debug mode if any events were added. 481 */ 482 void event_disable_debug_mode(void); 483 484 #ifdef __cplusplus 485 } 486 #endif 487 488 #endif /* EVENT_INTERNAL_H_INCLUDED_ */