third_party/libevent/kqueue.c

   1 /*      $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art Exp $  */
   2
   3 /*
   4  * Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
   5  * All rights reserved.
   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 THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #define _GNU_SOURCE 1
  34
  35 #include <sys/types.h>
  36 #ifdef HAVE_SYS_TIME_H
  37 #include <sys/time.h>
  38 #else
  39 #include <sys/_libevent_time.h>
  40 #endif
  41 #include <sys/queue.h>
  42 #include <sys/event.h>
  43 #include <signal.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48 #include <errno.h>
  49 #include <assert.h>
  50 #ifdef HAVE_INTTYPES_H
  51 #include <inttypes.h>
  52 #endif
  53
  54 /* Some platforms apparently define the udata field of struct kevent as
  55  * intptr_t, whereas others define it as void*.  There doesn't seem to be an
  56  * easy way to tell them apart via autoconf, so we need to use OS macros. */
  57 #if defined(HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__)
  58 #define PTR_TO_UDATA(x) ((intptr_t)(x))
  59 #else
  60 #define PTR_TO_UDATA(x) (x)
  61 #endif
  62
  63 #include "event.h"
  64 #include "event-internal.h"
  65 #include "log.h"
  66
  67 #define EVLIST_X_KQINKERNEL     0x1000
  68
  69 #define NEVENT          64
  70
  71 struct kqop {
  72         struct kevent *changes;
  73         int nchanges;
  74         struct kevent *events;
  75         struct event_list evsigevents[NSIG];
  76         int nevents;
  77         int kq;
  78         pid_t pid;
  79 };
  80
  81 static void *kq_init    (struct event_base *);
  82 static int kq_add       (void *, struct event *);
  83 static int kq_del       (void *, struct event *);
  84 static int kq_dispatch  (struct event_base *, void *, struct timeval *);
  85 static int kq_insert    (struct kqop *, struct kevent *);
  86 static void kq_dealloc (struct event_base *, void *);
  87
  88 const struct eventop kqops = {
  89         "kqueue",
  90         kq_init,
  91         kq_add,
  92         kq_del,
  93         kq_dispatch,
  94         kq_dealloc,
  95         1 /* need reinit */
  96 };
  97
  98 static void *
  99 kq_init(struct event_base *base)
 100 {
 101         int i, kq;
 102         struct kqop *kqueueop;
 103
 104         /* Disable kqueue when this environment variable is set */
 105         if (evutil_getenv("EVENT_NOKQUEUE"))
 106                 return (NULL);
 107
 108         if (!(kqueueop = calloc(1, sizeof(struct kqop))))
 109                 return (NULL);
 110
 111         /* Initalize the kernel queue */
 112
 113         if ((kq = kqueue()) == -1) {
 114                 event_warn("kqueue");
 115                 free (kqueueop);
 116                 return (NULL);
 117         }
 118
 119         kqueueop->kq = kq;
 120
 121         kqueueop->pid = getpid();
 122
 123         /* Initalize fields */
 124         kqueueop->changes = malloc(NEVENT * sizeof(struct kevent));
 125         if (kqueueop->changes == NULL) {
 126                 free (kqueueop);
 127                 return (NULL);
 128         }
 129         kqueueop->events = malloc(NEVENT * sizeof(struct kevent));
 130         if (kqueueop->events == NULL) {
 131                 free (kqueueop->changes);
 132                 free (kqueueop);
 133                 return (NULL);
 134         }
 135         kqueueop->nevents = NEVENT;
 136
 137         /* we need to keep track of multiple events per signal */
 138         for (i = 0; i < NSIG; ++i) {
 139                 TAILQ_INIT(&kqueueop->evsigevents[i]);
 140         }
 141
 142         /* Check for Mac OS X kqueue bug. */
 143         kqueueop->changes[0].ident = -1;
 144         kqueueop->changes[0].filter = EVFILT_READ;
 145         kqueueop->changes[0].flags = EV_ADD;
 146         /*
 147          * If kqueue works, then kevent will succeed, and it will
 148          * stick an error in events[0].  If kqueue is broken, then
 149          * kevent will fail.
 150          */
 151         if (kevent(kq,
 152                 kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 ||
 153             kqueueop->events[0].ident != -1 ||
 154             kqueueop->events[0].flags != EV_ERROR) {
 155                 event_warn("%s: detected broken kqueue; not using.", __func__);
 156                 free(kqueueop->changes);
 157                 free(kqueueop->events);
 158                 free(kqueueop);
 159                 close(kq);
 160                 return (NULL);
 161         }
 162
 163         return (kqueueop);
 164 }
 165
 166 static int
 167 kq_insert(struct kqop *kqop, struct kevent *kev)
 168 {
 169         int nevents = kqop->nevents;
 170
 171         if (kqop->nchanges == nevents) {
 172                 struct kevent *newchange;
 173                 struct kevent *newresult;
 174
 175                 nevents *= 2;
 176
 177                 newchange = realloc(kqop->changes,
 178                                     nevents * sizeof(struct kevent));
 179                 if (newchange == NULL) {
 180                         event_warn("%s: malloc", __func__);
 181                         return (-1);
 182                 }
 183                 kqop->changes = newchange;
 184
 185                 newresult = realloc(kqop->events,
 186                                     nevents * sizeof(struct kevent));
 187
 188                 /*
 189                  * If we fail, we don't have to worry about freeing,
 190                  * the next realloc will pick it up.
 191                  */
 192                 if (newresult == NULL) {
 193                         event_warn("%s: malloc", __func__);
 194                         return (-1);
 195                 }
 196                 kqop->events = newresult;
 197
 198                 kqop->nevents = nevents;
 199         }
 200
 201         memcpy(&kqop->changes[kqop->nchanges++], kev, sizeof(struct kevent));
 202
 203         event_debug(("%s: fd %d %s%s",
 204                 __func__, (int)kev->ident,
 205                 kev->filter == EVFILT_READ ? "EVFILT_READ" : "EVFILT_WRITE",
 206                 kev->flags == EV_DELETE ? " (del)" : ""));
 207
 208         return (0);
 209 }
 210
 211 static void
 212 kq_sighandler(int sig)
 213 {
 214         /* Do nothing here */
 215 }
 216
 217 static int
 218 kq_dispatch(struct event_base *base, void *arg, struct timeval *tv)
 219 {
 220         struct kqop *kqop = arg;
 221         struct kevent *changes = kqop->changes;
 222         struct kevent *events = kqop->events;
 223         struct event *ev;
 224         struct timespec ts, *ts_p = NULL;
 225         int i, res;
 226
 227         if (tv != NULL) {
 228                 TIMEVAL_TO_TIMESPEC(tv, &ts);
 229                 ts_p = &ts;
 230         }
 231
 232         res = kevent(kqop->kq, changes, kqop->nchanges,
 233             events, kqop->nevents, ts_p);
 234         kqop->nchanges = 0;
 235         if (res == -1) {
 236                 if (errno != EINTR) {
 237                         event_warn("kevent");
 238                         return (-1);
 239                 }
 240
 241                 return (0);
 242         }
 243
 244         event_debug(("%s: kevent reports %d", __func__, res));
 245
 246         for (i = 0; i < res; i++) {
 247                 int which = 0;
 248
 249                 if (events[i].flags & EV_ERROR) {
 250                         /*
 251                          * Error messages that can happen, when a delete fails.
 252                          *   EBADF happens when the file discriptor has been
 253                          *   closed,
 254                          *   ENOENT when the file discriptor was closed and
 255                          *   then reopened.
 256                          *   EINVAL for some reasons not understood; EINVAL
 257                          *   should not be returned ever; but FreeBSD does :-\
 258                          * An error is also indicated when a callback deletes
 259                          * an event we are still processing.  In that case
 260                          * the data field is set to ENOENT.
 261                          */
 262                         if (events[i].data == EBADF ||
 263                             events[i].data == EINVAL ||
 264                             events[i].data == ENOENT)
 265                                 continue;
 266                         errno = events[i].data;
 267                         return (-1);
 268                 }
 269
 270                 if (events[i].filter == EVFILT_READ) {
 271                         which |= EV_READ;
 272                 } else if (events[i].filter == EVFILT_WRITE) {
 273                         which |= EV_WRITE;
 274                 } else if (events[i].filter == EVFILT_SIGNAL) {
 275                         which |= EV_SIGNAL;
 276                 }
 277
 278                 if (!which)
 279                         continue;
 280
 281                 if (events[i].filter == EVFILT_SIGNAL) {
 282                         struct event_list *head =
 283                             (struct event_list *)events[i].udata;
 284                         TAILQ_FOREACH(ev, head, ev_signal_next) {
 285                                 event_active(ev, which, events[i].data);
 286                         }
 287                 } else {
 288                         ev = (struct event *)events[i].udata;
 289
 290                         if (!(ev->ev_events & EV_PERSIST))
 291                                 ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
 292
 293                         event_active(ev, which, 1);
 294                 }
 295         }
 296
 297         return (0);
 298 }
 299
 300
 301 static int
 302 kq_add(void *arg, struct event *ev)
 303 {
 304         struct kqop *kqop = arg;
 305         struct kevent kev;
 306
 307         if (ev->ev_events & EV_SIGNAL) {
 308                 int nsignal = EVENT_SIGNAL(ev);
 309
 310                 assert(nsignal >= 0 && nsignal < NSIG);
 311                 if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) {
 312                         struct timespec timeout = { 0, 0 };
 313
 314                         memset(&kev, 0, sizeof(kev));
 315                         kev.ident = nsignal;
 316                         kev.filter = EVFILT_SIGNAL;
 317                         kev.flags = EV_ADD;
 318                         kev.udata = PTR_TO_UDATA(&kqop->evsigevents[nsignal]);
 319
 320                         /* Be ready for the signal if it is sent any
 321                          * time between now and the next call to
 322                          * kq_dispatch. */
 323                         if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
 324                                 return (-1);
 325
 326                         if (_evsignal_set_handler(ev->ev_base, nsignal,
 327                                 kq_sighandler) == -1)
 328                                 return (-1);
 329                 }
 330
 331                 TAILQ_INSERT_TAIL(&kqop->evsigevents[nsignal], ev,
 332                     ev_signal_next);
 333                 ev->ev_flags |= EVLIST_X_KQINKERNEL;
 334                 return (0);
 335         }
 336
 337         if (ev->ev_events & EV_READ) {
 338                 memset(&kev, 0, sizeof(kev));
 339                 kev.ident = ev->ev_fd;
 340                 kev.filter = EVFILT_READ;
 341 #ifdef NOTE_EOF
 342                 /* Make it behave like select() and poll() */
 343                 kev.fflags = NOTE_EOF;
 344 #endif
 345                 kev.flags = EV_ADD;
 346                 if (!(ev->ev_events & EV_PERSIST))
 347                         kev.flags |= EV_ONESHOT;
 348                 kev.udata = PTR_TO_UDATA(ev);
 349
 350                 if (kq_insert(kqop, &kev) == -1)
 351                         return (-1);
 352
 353                 ev->ev_flags |= EVLIST_X_KQINKERNEL;
 354         }
 355
 356         if (ev->ev_events & EV_WRITE) {
 357                 memset(&kev, 0, sizeof(kev));
 358                 kev.ident = ev->ev_fd;
 359                 kev.filter = EVFILT_WRITE;
 360                 kev.flags = EV_ADD;
 361                 if (!(ev->ev_events & EV_PERSIST))
 362                         kev.flags |= EV_ONESHOT;
 363                 kev.udata = PTR_TO_UDATA(ev);
 364
 365                 if (kq_insert(kqop, &kev) == -1)
 366                         return (-1);
 367
 368                 ev->ev_flags |= EVLIST_X_KQINKERNEL;
 369         }
 370
 371         return (0);
 372 }
 373
 374 static int
 375 kq_del(void *arg, struct event *ev)
 376 {
 377         struct kqop *kqop = arg;
 378         struct kevent kev;
 379
 380         if (!(ev->ev_flags & EVLIST_X_KQINKERNEL))
 381                 return (0);
 382
 383         if (ev->ev_events & EV_SIGNAL) {
 384                 int nsignal = EVENT_SIGNAL(ev);
 385                 struct timespec timeout = { 0, 0 };
 386
 387                 assert(nsignal >= 0 && nsignal < NSIG);
 388                 TAILQ_REMOVE(&kqop->evsigevents[nsignal], ev, ev_signal_next);
 389                 if (TAILQ_EMPTY(&kqop->evsigevents[nsignal])) {
 390                         memset(&kev, 0, sizeof(kev));
 391                         kev.ident = nsignal;
 392                         kev.filter = EVFILT_SIGNAL;
 393                         kev.flags = EV_DELETE;
 394
 395                         /* Because we insert signal events
 396                          * immediately, we need to delete them
 397                          * immediately, too */
 398                         if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
 399                                 return (-1);
 400
 401                         if (_evsignal_restore_handler(ev->ev_base,
 402                                 nsignal) == -1)
 403                                 return (-1);
 404                 }
 405
 406                 ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
 407                 return (0);
 408         }
 409
 410         if (ev->ev_events & EV_READ) {
 411                 memset(&kev, 0, sizeof(kev));
 412                 kev.ident = ev->ev_fd;
 413                 kev.filter = EVFILT_READ;
 414                 kev.flags = EV_DELETE;
 415
 416                 if (kq_insert(kqop, &kev) == -1)
 417                         return (-1);
 418
 419                 ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
 420         }
 421
 422         if (ev->ev_events & EV_WRITE) {
 423                 memset(&kev, 0, sizeof(kev));
 424                 kev.ident = ev->ev_fd;
 425                 kev.filter = EVFILT_WRITE;
 426                 kev.flags = EV_DELETE;
 427
 428                 if (kq_insert(kqop, &kev) == -1)
 429                         return (-1);
 430
 431                 ev->ev_flags &= ~EVLIST_X_KQINKERNEL;
 432         }
 433
 434         return (0);
 435 }
 436
 437 static void
 438 kq_dealloc(struct event_base *base, void *arg)
 439 {
 440         struct kqop *kqop = arg;
 441
 442         if (kqop->changes)
 443                 free(kqop->changes);
 444         if (kqop->events)
 445                 free(kqop->events);
 446         if (kqop->kq >= 0 && kqop->pid == getpid())
 447                 close(kqop->kq);
 448         memset(kqop, 0, sizeof(struct kqop));
 449         free(kqop);
 450 }