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_
28 #define _EVENT_INTERNAL_H_
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34 #include "event2/event-config.h"
35 #include <time.h>
36 #include <sys/queue.h>
37 #include "event2/event_struct.h"
38 #include "minheap-internal.h"
39 #include "evsignal-internal.h"
40 #include "mm-internal.h"
41 #include "defer-internal.h"
42
43 /* map union members back */
44
45 /* mutually exclusive */
46 #define ev_signal_next _ev.ev_signal.ev_signal_next
47 #define ev_io_next _ev.ev_io.ev_io_next
48 #define ev_io_timeout _ev.ev_io.ev_timeout
49
50 /* used only by signals */
51 #define ev_ncalls _ev.ev_signal.ev_ncalls
52 #define ev_pncalls _ev.ev_signal.ev_pncalls
53
54 /* Possible values for ev_closure in struct event. */
55 #define EV_CLOSURE_NONE 0
56 #define EV_CLOSURE_SIGNAL 1
57 #define EV_CLOSURE_PERSIST 2
58
59 /** Structure to define the backend of a given event_base. */
60 struct eventop {
61 /** The name of this backend. */
62 const char *name;
63 /** Function to set up an event_base to use this backend. It should
64 * create a new structure holding whatever information is needed to
65 * run the backend, and return it. The returned pointer will get
66 * stored by event_init into the event_base.evbase field. On failure,
67 * this function should return NULL. */
68 void *(*init)(struct event_base *);
69 /** Enable reading/writing on a given fd or signal. 'events' will be
70 * the events that we're trying to enable: one or more of EV_READ,
71 * EV_WRITE, EV_SIGNAL, and EV_ET. 'old' will be those events that
72 * were enabled on this fd previously. 'fdinfo' will be a structure
73 * associated with the fd by the evmap; its size is defined by the
74 * fdinfo field below. It will be set to 0 the first time the fd is
75 * added. The function should return 0 on success and -1 on error.
76 */
77 int (*add)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo);
78 /** As "add", except 'events' contains the events we mean to disable. */
79 int (*del)(struct event_base *, evutil_socket_t fd, short old, short events, void *fdinfo);
80 /** Function to implement the core of an event loop. It must see which
81 added events are ready, and cause event_active to be called for each
82 active event (usually via event_io_active or such). It should
83 return 0 on success and -1 on error.
84 */
85 int (*dispatch)(struct event_base *, struct timeval *);
86 /** Function to clean up and free our data from the event_base. */
87 void (*dealloc)(struct event_base *);
88 /** Flag: set if we need to reinitialize the event base after we fork.
89 */
90 int need_reinit;
91 /** Bit-array of supported event_method_features that this backend can
92 * provide. */
93 enum event_method_feature features;
94 /** Length of the extra information we should record for each fd that
95 has one or more active events. This information is recorded
96 as part of the evmap entry for each fd, and passed as an argument
97 to the add and del functions above.
98 */
99 size_t fdinfo_len;
100 };
101
102 #ifdef WIN32
103 /* If we're on win32, then file descriptors are not nice low densely packed
104 integers. Instead, they are pointer-like windows handles, and we want to
105 use a hashtable instead of an array to map fds to events.
106 */
107 #define EVMAP_USE_HT
108 #endif
109
110 /* #define HT_CACHE_HASH_VALS */
111
112 #ifdef EVMAP_USE_HT
113 #include "ht-internal.h"
114 struct event_map_entry;
115 HT_HEAD(event_io_map, event_map_entry);
116 #else
117 #define event_io_map event_signal_map
118 #endif
119
120 /* Used to map signal numbers to a list of events. If EVMAP_USE_HT is not
121 defined, this structure is also used as event_io_map, which maps fds to a
122 list of events.
123 */
124 struct event_signal_map {
125 /* An array of evmap_io * or of evmap_signal *; empty entries are
126 * set to NULL. */
127 void **entries;
128 /* The number of entries available in entries */
129 int nentries;
130 };
131
132 /* A list of events waiting on a given 'common' timeout value. Ordinarily,
133 * events waiting for a timeout wait on a minheap. Sometimes, however, a
134 * queue can be faster.
135 **/
136 struct common_timeout_list {
137 /* List of events currently waiting in the queue. */
138 struct event_list events;
139 /* 'magic' timeval used to indicate the duration of events in this
140 * queue. */
141 struct timeval duration;
142 /* Event that triggers whenever one of the events in the queue is
143 * ready to activate */
144 struct event timeout_event;
145 /* The event_base that this timeout list is part of */
146 struct event_base *base;
147 };
148
149 /** Mask used to get the real tv_usec value from a common timeout. */
150 #define COMMON_TIMEOUT_MICROSECONDS_MASK 0x000fffff
151
152 struct event_change;
153
154 /* List of 'changes' since the last call to eventop.dispatch. Only maintained
155 * if the backend is using changesets. */
156 struct event_changelist {
157 struct event_change *changes;
158 int n_changes;
159 int changes_size;
160 };
161
162 #ifndef _EVENT_DISABLE_DEBUG_MODE
163 /* Global internal flag: set to one if debug mode is on. */
164 extern int ompi__event_debug_mode_on;
165 #define EVENT_DEBUG_MODE_IS_ON() (ompi__event_debug_mode_on)
166 #else
167 #define EVENT_DEBUG_MODE_IS_ON() (0)
168 #endif
169
170 struct event_base {
171 /** Function pointers and other data to describe this event_base's
172 * backend. */
173 const struct eventop *evsel;
174 /** Pointer to backend-specific data. */
175 void *evbase;
176
177 /** List of changes to tell backend about at next dispatch. Only used
178 * by the O(1) backends. */
179 struct event_changelist changelist;
180
181 /** Function pointers used to describe the backend that this event_base
182 * uses for signals */
183 const struct eventop *evsigsel;
184 /** Data to implement the common signal handelr code. */
185 struct evsig_info sig;
186
187 /** Number of virtual events */
188 int virtual_event_count;
189 /** Number of total events added to this event_base */
190 int event_count;
191 /** Number of total events active in this event_base */
192 int event_count_active;
193
194 /** Set if we should terminate the loop once we're done processing
195 * events. */
196 int event_gotterm;
197 /** Set if we should terminate the loop immediately */
198 int event_break;
199 /** Set if we should start a new instance of the loop immediately. */
200 int event_continue;
201
202 /** The currently running priority of events */
203 int event_running_priority;
204
205 /** Set if we're running the event_base_loop function, to prevent
206 * reentrant invocation. */
207 int running_loop;
208
209 /* Active event management. */
210 /** An array of nactivequeues queues for active events (ones that
211 * have triggered, and whose callbacks need to be called). Low
212 * priority numbers are more important, and stall higher ones.
213 */
214 struct event_list *activequeues;
215 /** The length of the activequeues array */
216 int nactivequeues;
217
218 /* common timeout logic */
219
220 /** An array of common_timeout_list* for all of the common timeout
221 * values we know. */
222 struct common_timeout_list **common_timeout_queues;
223 /** The number of entries used in common_timeout_queues */
224 int n_common_timeouts;
225 /** The total size of common_timeout_queues. */
226 int n_common_timeouts_allocated;
227
228 /** List of defered_cb that are active. We run these after the active
229 * events. */
230 struct deferred_cb_queue defer_queue;
231
232 /** Mapping from file descriptors to enabled (added) events */
233 struct event_io_map io;
234
235 /** Mapping from signal numbers to enabled (added) events. */
236 struct event_signal_map sigmap;
237
238 /** All events that have been enabled (added) in this event_base */
239 struct event_list eventqueue;
240
241 /** Stored timeval; used to detect when time is running backwards. */
242 struct timeval event_tv;
243
244 /** Priority queue of events with timeouts. */
245 struct min_heap timeheap;
246
247 /** Stored timeval: used to avoid calling gettimeofday/clock_gettime
248 * too often. */
249 struct timeval tv_cache;
250
251 #if defined(_EVENT_HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
252 /** Difference between internal time (maybe from clock_gettime) and
253 * gettimeofday. */
254 struct timeval tv_clock_diff;
255 /** Second in which we last updated tv_clock_diff, in monotonic time. */
256 time_t last_updated_clock_diff;
257 #endif
258
259 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
260 /* threading support */
261 /** The thread currently running the event_loop for this base */
262 unsigned long th_owner_id;
263 /** A lock to prevent conflicting accesses to this event_base */
264 void *th_base_lock;
265 /** The event whose callback is executing right now */
266 struct event *current_event;
267 /** A condition that gets signalled when we're done processing an
268 * event with waiters on it. */
269 void *current_event_cond;
270 /** Number of threads blocking on current_event_cond. */
271 int current_event_waiters;
272 #endif
273
274 #ifdef WIN32
275 /** IOCP support structure, if IOCP is enabled. */
276 struct event_iocp_port *iocp;
277 #endif
278
279 /** Flags that this base was configured with */
280 enum event_base_config_flag flags;
281
282 /* Notify main thread to wake up break, etc. */
283 /** True if the base already has a pending notify, and we don't need
284 * to add any more. */
285 int is_notify_pending;
286 /** A socketpair used by some th_notify functions to wake up the main
287 * thread. */
288 evutil_socket_t th_notify_fd[2];
289 /** An event used by some th_notify functions to wake up the main
290 * thread. */
291 struct event th_notify;
292 /** A function used to wake up the main thread from another thread. */
293 int (*th_notify_fn)(struct event_base *base);
294 };
295
296 struct event_config_entry {
297 TAILQ_ENTRY(event_config_entry) next;
298
299 const char *avoid_method;
300 };
301
302 /** Internal structure: describes the configuration we want for an event_base
303 * that we're about to allocate. */
304 struct event_config {
305 TAILQ_HEAD(event_configq, event_config_entry) entries;
306
307 int n_cpus_hint;
308 enum event_method_feature require_features;
309 enum event_base_config_flag flags;
310 };
311
312 /* Internal use only: Functions that might be missing from <sys/queue.h> */
313 #if defined(_EVENT_HAVE_SYS_QUEUE_H) && !defined(_EVENT_HAVE_TAILQFOREACH)
314 #ifndef TAILQ_FIRST
315 #define TAILQ_FIRST(head) ((head)->tqh_first)
316 #endif
317 #ifndef TAILQ_END
318 #define TAILQ_END(head) NULL
319 #endif
320 #ifndef TAILQ_NEXT
321 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
322 #endif
323
324 #ifndef TAILQ_FOREACH
325 #define TAILQ_FOREACH(var, head, field) \
326 for ((var) = TAILQ_FIRST(head); \
327 (var) != TAILQ_END(head); \
328 (var) = TAILQ_NEXT(var, field))
329 #endif
330
331 #ifndef TAILQ_INSERT_BEFORE
332 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
333 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
334 (elm)->field.tqe_next = (listelm); \
335 *(listelm)->field.tqe_prev = (elm); \
336 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
337 } while (0)
338 #endif
339 #endif /* TAILQ_FOREACH */
340
341 #define N_ACTIVE_CALLBACKS(base) \
342 ((base)->event_count_active + (base)->defer_queue.active_count)
343
344 int _evsig_set_handler(struct event_base *base, int evsignal,
345 void (*fn)(int));
346 int _evsig_restore_handler(struct event_base *base, int evsignal);
347
348
349 void event_active_nolock(struct event *ev, int res, short count);
350
351 /* FIXME document. */
352 void event_base_add_virtual(struct event_base *base);
353 void event_base_del_virtual(struct event_base *base);
354
355 /** For debugging: unless assertions are disabled, verify the referential
356 integrity of the internal data structures of 'base'. This operation can
357 be expensive.
358
359 Returns on success; aborts on failure.
360 */
361 void event_base_assert_ok(struct event_base *base);
362
363 #ifdef __cplusplus
364 }
365 #endif
366
367 #endif /* _EVENT_INTERNAL_H_ */
368