1 /*
2 * Submitted by David Pacheco (dp.spambait@gmail.com)
3 *
4 * Copyright 2006-2007 Niels Provos
5 * Copyright 2007-2012 Niels Provos and Nick Mathewson
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY SUN MICROSYSTEMS, INC. ``AS IS'' AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL SUN MICROSYSTEMS, INC. BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /*
31 * Copyright (c) 2007 Sun Microsystems. All rights reserved.
32 * Use is subject to license terms.
33 */
34
35 /*
36 * evport.c: event backend using Solaris 10 event ports. See port_create(3C).
37 * This implementation is loosely modeled after the one used for select(2) (in
38 * select.c).
39 *
40 * The outstanding events are tracked in a data structure called evport_data.
41 * Each entry in the ed_fds array corresponds to a file descriptor, and contains
42 * pointers to the read and write events that correspond to that fd. (That is,
43 * when the file is readable, the "read" event should handle it, etc.)
44 *
45 * evport_add and evport_del update this data structure. evport_dispatch uses it
46 * to determine where to callback when an event occurs (which it gets from
47 * port_getn).
48 *
49 * Helper functions are used: grow() grows the file descriptor array as
50 * necessary when large fd's come in. reassociate() takes care of maintaining
51 * the proper file-descriptor/event-port associations.
52 *
53 * As in the select(2) implementation, signals are handled by evsignal.
54 */
55
56 #include "event2/event-config.h"
57
58 #include <sys/time.h>
59 #include <sys/queue.h>
60 #include <errno.h>
61 #include <poll.h>
62 #include <port.h>
63 #include <signal.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <time.h>
68 #include <unistd.h>
69
70 #include "event2/thread.h"
71
72 #include "evthread-internal.h"
73 #include "event-internal.h"
74 #include "log-internal.h"
75 #include "evsignal-internal.h"
76 #include "evmap-internal.h"
77
78 /*
79 * Default value for ed_nevents, which is the maximum file descriptor number we
80 * can handle. If an event comes in for a file descriptor F > nevents, we will
81 * grow the array of file descriptors, doubling its size.
82 */
83 #define DEFAULT_NFDS 16
84
85
86 /*
87 * EVENTS_PER_GETN is the maximum number of events to retrieve from port_getn on
88 * any particular call. You can speed things up by increasing this, but it will
89 * (obviously) require more memory.
90 */
91 #define EVENTS_PER_GETN 8
92
93 /*
94 * Per-file-descriptor information about what events we're subscribed to. These
95 * fields are NULL if no event is subscribed to either of them.
96 */
97
98 struct fd_info {
99 short fdi_what; /* combinations of EV_READ and EV_WRITE */
100 };
101
102 #define FDI_HAS_READ(fdi) ((fdi)->fdi_what & EV_READ)
103 #define FDI_HAS_WRITE(fdi) ((fdi)->fdi_what & EV_WRITE)
104 #define FDI_HAS_EVENTS(fdi) (FDI_HAS_READ(fdi) || FDI_HAS_WRITE(fdi))
105 #define FDI_TO_SYSEVENTS(fdi) (FDI_HAS_READ(fdi) ? POLLIN : 0) | \
106 (FDI_HAS_WRITE(fdi) ? POLLOUT : 0)
107
108 struct evport_data {
109 int ed_port; /* event port for system events */
110 int ed_nevents; /* number of allocated fdi's */
111 struct fd_info *ed_fds; /* allocated fdi table */
112 /* fdi's that we need to reassoc */
113 int ed_pending[EVENTS_PER_GETN]; /* fd's with pending events */
114 };
115
116 static void* evport_init(struct event_base *);
117 static int evport_add(struct event_base *, int fd, short old, short events, void *);
118 static int evport_del(struct event_base *, int fd, short old, short events, void *);
119 static int evport_dispatch(struct event_base *, struct timeval *);
120 static void evport_dealloc(struct event_base *);
121
122 const struct eventop evportops = {
123 "evport",
124 evport_init,
125 evport_add,
126 evport_del,
127 evport_dispatch,
128 evport_dealloc,
129 1, /* need reinit */
130 0, /* features */
131 0, /* fdinfo length */
132 };
133
134 /*
135 * Initialize the event port implementation.
136 */
137
138 static void*
evport_init(struct event_base * base)139 evport_init(struct event_base *base)
140 {
141 struct evport_data *evpd;
142 int i;
143
144 if (!(evpd = mm_calloc(1, sizeof(struct evport_data))))
145 return (NULL);
146
147 if ((evpd->ed_port = port_create()) == -1) {
148 mm_free(evpd);
149 return (NULL);
150 }
151
152 /*
153 * Initialize file descriptor structure
154 */
155 evpd->ed_fds = mm_calloc(DEFAULT_NFDS, sizeof(struct fd_info));
156 if (evpd->ed_fds == NULL) {
157 close(evpd->ed_port);
158 mm_free(evpd);
159 return (NULL);
160 }
161 evpd->ed_nevents = DEFAULT_NFDS;
162 for (i = 0; i < EVENTS_PER_GETN; i++)
163 evpd->ed_pending[i] = -1;
164
165 evsig_init(base);
166
167 return (evpd);
168 }
169
170 #ifdef CHECK_INVARIANTS
171 /*
172 * Checks some basic properties about the evport_data structure. Because it
173 * checks all file descriptors, this function can be expensive when the maximum
174 * file descriptor ever used is rather large.
175 */
176
177 static void
check_evportop(struct evport_data * evpd)178 check_evportop(struct evport_data *evpd)
179 {
180 EVUTIL_ASSERT(evpd);
181 EVUTIL_ASSERT(evpd->ed_nevents > 0);
182 EVUTIL_ASSERT(evpd->ed_port > 0);
183 EVUTIL_ASSERT(evpd->ed_fds > 0);
184 }
185
186 /*
187 * Verifies very basic integrity of a given port_event.
188 */
189 static void
check_event(port_event_t * pevt)190 check_event(port_event_t* pevt)
191 {
192 /*
193 * We've only registered for PORT_SOURCE_FD events. The only
194 * other thing we can legitimately receive is PORT_SOURCE_ALERT,
195 * but since we're not using port_alert either, we can assume
196 * PORT_SOURCE_FD.
197 */
198 EVUTIL_ASSERT(pevt->portev_source == PORT_SOURCE_FD);
199 EVUTIL_ASSERT(pevt->portev_user == NULL);
200 }
201
202 #else
203 #define check_evportop(epop)
204 #define check_event(pevt)
205 #endif /* CHECK_INVARIANTS */
206
207 /*
208 * Doubles the size of the allocated file descriptor array.
209 */
210 static int
grow(struct evport_data * epdp,int factor)211 grow(struct evport_data *epdp, int factor)
212 {
213 struct fd_info *tmp;
214 int oldsize = epdp->ed_nevents;
215 int newsize = factor * oldsize;
216 EVUTIL_ASSERT(factor > 1);
217
218 check_evportop(epdp);
219
220 tmp = mm_realloc(epdp->ed_fds, sizeof(struct fd_info) * newsize);
221 if (NULL == tmp)
222 return -1;
223 epdp->ed_fds = tmp;
224 memset((char*) (epdp->ed_fds + oldsize), 0,
225 (newsize - oldsize)*sizeof(struct fd_info));
226 epdp->ed_nevents = newsize;
227
228 check_evportop(epdp);
229
230 return 0;
231 }
232
233
234 /*
235 * (Re)associates the given file descriptor with the event port. The OS events
236 * are specified (implicitly) from the fd_info struct.
237 */
238 static int
reassociate(struct evport_data * epdp,struct fd_info * fdip,int fd)239 reassociate(struct evport_data *epdp, struct fd_info *fdip, int fd)
240 {
241 int sysevents = FDI_TO_SYSEVENTS(fdip);
242
243 if (sysevents != 0) {
244 if (port_associate(epdp->ed_port, PORT_SOURCE_FD,
245 fd, sysevents, NULL) == -1) {
246 event_warn("port_associate");
247 return (-1);
248 }
249 }
250
251 check_evportop(epdp);
252
253 return (0);
254 }
255
256 /*
257 * Main event loop - polls port_getn for some number of events, and processes
258 * them.
259 */
260
261 static int
evport_dispatch(struct event_base * base,struct timeval * tv)262 evport_dispatch(struct event_base *base, struct timeval *tv)
263 {
264 int i, res;
265 struct evport_data *epdp = base->evbase;
266 port_event_t pevtlist[EVENTS_PER_GETN];
267
268 /*
269 * port_getn will block until it has at least nevents events. It will
270 * also return how many it's given us (which may be more than we asked
271 * for, as long as it's less than our maximum (EVENTS_PER_GETN)) in
272 * nevents.
273 */
274 int nevents = 1;
275
276 /*
277 * We have to convert a struct timeval to a struct timespec
278 * (only difference is nanoseconds vs. microseconds). If no time-based
279 * events are active, we should wait for I/O (and tv == NULL).
280 */
281 struct timespec ts;
282 struct timespec *ts_p = NULL;
283 if (tv != NULL) {
284 ts.tv_sec = tv->tv_sec;
285 ts.tv_nsec = tv->tv_usec * 1000;
286 ts_p = &ts;
287 }
288
289 /*
290 * Before doing anything else, we need to reassociate the events we hit
291 * last time which need reassociation. See comment at the end of the
292 * loop below.
293 */
294 for (i = 0; i < EVENTS_PER_GETN; ++i) {
295 struct fd_info *fdi = NULL;
296 if (epdp->ed_pending[i] != -1) {
297 fdi = &(epdp->ed_fds[epdp->ed_pending[i]]);
298 }
299
300 if (fdi != NULL && FDI_HAS_EVENTS(fdi)) {
301 int fd = epdp->ed_pending[i];
302 reassociate(epdp, fdi, fd);
303 epdp->ed_pending[i] = -1;
304 }
305 }
306
307 EVBASE_RELEASE_LOCK(base, th_base_lock);
308
309 res = port_getn(epdp->ed_port, pevtlist, EVENTS_PER_GETN,
310 (unsigned int *) &nevents, ts_p);
311
312 EVBASE_ACQUIRE_LOCK(base, th_base_lock);
313
314 if (res == -1) {
315 if (errno == EINTR || errno == EAGAIN) {
316 return (0);
317 } else if (errno == ETIME) {
318 if (nevents == 0)
319 return (0);
320 } else {
321 event_warn("port_getn");
322 return (-1);
323 }
324 }
325
326 event_debug(("%s: port_getn reports %d events", __func__, nevents));
327
328 for (i = 0; i < nevents; ++i) {
329 struct fd_info *fdi;
330 port_event_t *pevt = &pevtlist[i];
331 int fd = (int) pevt->portev_object;
332
333 check_evportop(epdp);
334 check_event(pevt);
335 epdp->ed_pending[i] = fd;
336
337 /*
338 * Figure out what kind of event it was
339 * (because we have to pass this to the callback)
340 */
341 res = 0;
342 if (pevt->portev_events & (POLLERR|POLLHUP)) {
343 res = EV_READ | EV_WRITE;
344 } else {
345 if (pevt->portev_events & POLLIN)
346 res |= EV_READ;
347 if (pevt->portev_events & POLLOUT)
348 res |= EV_WRITE;
349 }
350
351 /*
352 * Check for the error situations or a hangup situation
353 */
354 if (pevt->portev_events & (POLLERR|POLLHUP|POLLNVAL))
355 res |= EV_READ|EV_WRITE;
356
357 EVUTIL_ASSERT(epdp->ed_nevents > fd);
358 fdi = &(epdp->ed_fds[fd]);
359
360 evmap_io_active(base, fd, res);
361 } /* end of all events gotten */
362
363 check_evportop(epdp);
364
365 return (0);
366 }
367
368
369 /*
370 * Adds the given event (so that you will be notified when it happens via
371 * the callback function).
372 */
373
374 static int
evport_add(struct event_base * base,int fd,short old,short events,void * p)375 evport_add(struct event_base *base, int fd, short old, short events, void *p)
376 {
377 struct evport_data *evpd = base->evbase;
378 struct fd_info *fdi;
379 int factor;
380 (void)p;
381
382 check_evportop(evpd);
383
384 /*
385 * If necessary, grow the file descriptor info table
386 */
387
388 factor = 1;
389 while (fd >= factor * evpd->ed_nevents)
390 factor *= 2;
391
392 if (factor > 1) {
393 if (-1 == grow(evpd, factor)) {
394 return (-1);
395 }
396 }
397
398 fdi = &evpd->ed_fds[fd];
399 fdi->fdi_what |= events;
400
401 return reassociate(evpd, fdi, fd);
402 }
403
404 /*
405 * Removes the given event from the list of events to wait for.
406 */
407
408 static int
evport_del(struct event_base * base,int fd,short old,short events,void * p)409 evport_del(struct event_base *base, int fd, short old, short events, void *p)
410 {
411 struct evport_data *evpd = base->evbase;
412 struct fd_info *fdi;
413 int i;
414 int associated = 1;
415 (void)p;
416
417 check_evportop(evpd);
418
419 if (evpd->ed_nevents < fd) {
420 return (-1);
421 }
422
423 for (i = 0; i < EVENTS_PER_GETN; ++i) {
424 if (evpd->ed_pending[i] == fd) {
425 associated = 0;
426 break;
427 }
428 }
429
430 fdi = &evpd->ed_fds[fd];
431 if (events & EV_READ)
432 fdi->fdi_what &= ~EV_READ;
433 if (events & EV_WRITE)
434 fdi->fdi_what &= ~EV_WRITE;
435
436 if (associated) {
437 if (!FDI_HAS_EVENTS(fdi) &&
438 port_dissociate(evpd->ed_port, PORT_SOURCE_FD, fd) == -1) {
439 /*
440 * Ignore EBADFD error the fd could have been closed
441 * before event_del() was called.
442 */
443 if (errno != EBADFD) {
444 event_warn("port_dissociate");
445 return (-1);
446 }
447 } else {
448 if (FDI_HAS_EVENTS(fdi)) {
449 return (reassociate(evpd, fdi, fd));
450 }
451 }
452 } else {
453 if ((fdi->fdi_what & (EV_READ|EV_WRITE)) == 0) {
454 evpd->ed_pending[i] = -1;
455 }
456 }
457 return 0;
458 }
459
460
461 static void
evport_dealloc(struct event_base * base)462 evport_dealloc(struct event_base *base)
463 {
464 struct evport_data *evpd = base->evbase;
465
466 evsig_dealloc(base);
467
468 close(evpd->ed_port);
469
470 if (evpd->ed_fds)
471 mm_free(evpd->ed_fds);
472 mm_free(evpd);
473 }
474