release/src/router/libevent/kqueue.c

   1 /*      $OpenBSD: kqueue.c,v 1.5 2002/07/10 14:41:31 art Exp $  */
   2
   3 /*
   4  * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
   5  * Copyright 2007-2010 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 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 #include "event2/event-config.h"
  30
  31 #define _GNU_SOURCE
  32
  33 #include <sys/types.h>
  34 #ifdef _EVENT_HAVE_SYS_TIME_H
  35 #include <sys/time.h>
  36 #endif
  37 #include <sys/queue.h>
  38 #include <sys/event.h>
  39 #include <signal.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <errno.h>
  45 #ifdef _EVENT_HAVE_INTTYPES_H
  46 #include <inttypes.h>
  47 #endif
  48
  49 /* Some platforms apparently define the udata field of struct kevent as
  50  * intptr_t, whereas others define it as void*.  There doesn't seem to be an
  51  * easy way to tell them apart via autoconf, so we need to use OS macros. */
  52 #if defined(_EVENT_HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__)
  53 #define PTR_TO_UDATA(x) ((intptr_t)(x))
  54 #else
  55 #define PTR_TO_UDATA(x) (x)
  56 #endif
  57
  58 #include "event-internal.h"
  59 #include "log-internal.h"
  60 #include "evmap-internal.h"
  61 #include "event2/thread.h"
  62 #include "evthread-internal.h"
  63 #include "changelist-internal.h"
  64
  65 #define NEVENT          64
  66
  67 struct kqop {
  68         struct kevent *changes;
  69         int changes_size;
  70
  71         struct kevent *events;
  72         int events_size;
  73         int kq;
  74         pid_t pid;
  75 };
  76
  77 static void kqop_free(struct kqop *kqop);
  78
  79 static void *kq_init(struct event_base *);
  80 static int kq_sig_add(struct event_base *, int, short, short, void *);
  81 static int kq_sig_del(struct event_base *, int, short, short, void *);
  82 static int kq_dispatch(struct event_base *, struct timeval *);
  83 static void kq_dealloc(struct event_base *);
  84
  85 const struct eventop kqops = {
  86         "kqueue",
  87         kq_init,
  88         event_changelist_add,
  89         event_changelist_del,
  90         kq_dispatch,
  91         kq_dealloc,
  92         1 /* need reinit */,
  93     EV_FEATURE_ET|EV_FEATURE_O1|EV_FEATURE_FDS,
  94         EVENT_CHANGELIST_FDINFO_SIZE
  95 };
  96
  97 static const struct eventop kqsigops = {
  98         "kqueue_signal",
  99         NULL,
 100         kq_sig_add,
 101         kq_sig_del,
 102         NULL,
 103         NULL,
 104         1 /* need reinit */,
 105         0,
 106         0
 107 };
 108
 109 static void *
 110 kq_init(struct event_base *base)
 111 {
 112         int kq = -1;
 113         struct kqop *kqueueop = NULL;
 114
 115         if (!(kqueueop = mm_calloc(1, sizeof(struct kqop))))
 116                 return (NULL);
 117
 118 /* Initialize the kernel queue */
 119
 120         if ((kq = kqueue()) == -1) {
 121                 event_warn("kqueue");
 122                 goto err;
 123         }
 124
 125         kqueueop->kq = kq;
 126
 127         kqueueop->pid = getpid();
 128
 129         /* Initialize fields */
 130         kqueueop->changes = mm_calloc(NEVENT, sizeof(struct kevent));
 131         if (kqueueop->changes == NULL)
 132                 goto err;
 133         kqueueop->events = mm_calloc(NEVENT, sizeof(struct kevent));
 134         if (kqueueop->events == NULL)
 135                 goto err;
 136         kqueueop->events_size = kqueueop->changes_size = NEVENT;
 137
 138         /* Check for Mac OS X kqueue bug. */
 139         memset(&kqueueop->changes[0], 0, sizeof kqueueop->changes[0]);
 140         kqueueop->changes[0].ident = -1;
 141         kqueueop->changes[0].filter = EVFILT_READ;
 142         kqueueop->changes[0].flags = EV_ADD;
 143         /*
 144          * If kqueue works, then kevent will succeed, and it will
 145          * stick an error in events[0].  If kqueue is broken, then
 146          * kevent will fail.
 147          */
 148         if (kevent(kq,
 149                 kqueueop->changes, 1, kqueueop->events, NEVENT, NULL) != 1 ||
 150             (int)kqueueop->events[0].ident != -1 ||
 151             kqueueop->events[0].flags != EV_ERROR) {
 152                 event_warn("%s: detected broken kqueue; not using.", __func__);
 153                 goto err;
 154         }
 155
 156         base->evsigsel = &kqsigops;
 157
 158         return (kqueueop);
 159 err:
 160         if (kqueueop)
 161                 kqop_free(kqueueop);
 162
 163         return (NULL);
 164 }
 165
 166 static void
 167 kq_sighandler(int sig)
 168 {
 169         /* Do nothing here */
 170 }
 171
 172 static void
 173 kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change)
 174 {
 175         memset(out, 0, sizeof(out));
 176         out->ident = fd;
 177         out->filter = filter;
 178
 179         if (change & EV_CHANGE_ADD) {
 180                 out->flags = EV_ADD;
 181                 if (change & EV_ET)
 182                         out->flags |= EV_CLEAR;
 183 #ifdef NOTE_EOF
 184                 /* Make it behave like select() and poll() */
 185                 if (filter == EVFILT_READ)
 186                         out->fflags = NOTE_EOF;
 187 #endif
 188         } else {
 189                 EVUTIL_ASSERT(change & EV_CHANGE_DEL);
 190                 out->flags = EV_DELETE;
 191         }
 192 }
 193
 194 static int
 195 kq_build_changes_list(const struct event_changelist *changelist,
 196     struct kqop *kqop)
 197 {
 198         int i;
 199         int n_changes = 0;
 200
 201         for (i = 0; i < changelist->n_changes; ++i) {
 202                 struct event_change *in_ch = &changelist->changes[i];
 203                 struct kevent *out_ch;
 204                 if (n_changes >= kqop->changes_size - 1) {
 205                         int newsize = kqop->changes_size * 2;
 206                         struct kevent *newchanges;
 207
 208                         newchanges = mm_realloc(kqop->changes,
 209                             newsize * sizeof(struct kevent));
 210                         if (newchanges == NULL) {
 211                                 event_warn("%s: realloc", __func__);
 212                                 return (-1);
 213                         }
 214                         kqop->changes = newchanges;
 215                         kqop->changes_size = newsize;
 216                 }
 217                 if (in_ch->read_change) {
 218                         out_ch = &kqop->changes[n_changes++];
 219                         kq_setup_kevent(out_ch, in_ch->fd, EVFILT_READ,
 220                             in_ch->read_change);
 221                 }
 222                 if (in_ch->write_change) {
 223                         out_ch = &kqop->changes[n_changes++];
 224                         kq_setup_kevent(out_ch, in_ch->fd, EVFILT_WRITE,
 225                             in_ch->write_change);
 226                 }
 227         }
 228         return n_changes;
 229 }
 230
 231 static int
 232 kq_dispatch(struct event_base *base, struct timeval *tv)
 233 {
 234         struct kqop *kqop = base->evbase;
 235         struct kevent *events = kqop->events;
 236         struct kevent *changes;
 237         struct timespec ts, *ts_p = NULL;
 238         int i, n_changes, res;
 239
 240         if (tv != NULL) {
 241                 TIMEVAL_TO_TIMESPEC(tv, &ts);
 242                 ts_p = &ts;
 243         }
 244
 245         /* Build "changes" from "base->changes" */
 246         EVUTIL_ASSERT(kqop->changes);
 247         n_changes = kq_build_changes_list(&base->changelist, kqop);
 248         if (n_changes < 0)
 249                 return -1;
 250
 251         event_changelist_remove_all(&base->changelist, base);
 252
 253         /* steal the changes array in case some broken code tries to call
 254          * dispatch twice at once. */
 255         changes = kqop->changes;
 256         kqop->changes = NULL;
 257
 258         EVBASE_RELEASE_LOCK(base, th_base_lock);
 259
 260         res = kevent(kqop->kq, changes, n_changes,
 261             events, kqop->events_size, ts_p);
 262
 263         EVBASE_ACQUIRE_LOCK(base, th_base_lock);
 264
 265         EVUTIL_ASSERT(kqop->changes == NULL);
 266         kqop->changes = changes;
 267
 268         if (res == -1) {
 269                 if (errno != EINTR) {
 270                         event_warn("kevent");
 271                         return (-1);
 272                 }
 273
 274                 return (0);
 275         }
 276
 277         event_debug(("%s: kevent reports %d", __func__, res));
 278
 279         for (i = 0; i < res; i++) {
 280                 int which = 0;
 281
 282                 if (events[i].flags & EV_ERROR) {
 283                         /*
 284                          * Error messages that can happen, when a delete fails.
 285                          *   EBADF happens when the file descriptor has been
 286                          *   closed,
 287                          *   ENOENT when the file descriptor was closed and
 288                          *   then reopened.
 289                          *   EINVAL for some reasons not understood; EINVAL
 290                          *   should not be returned ever; but FreeBSD does :-\
 291                          * An error is also indicated when a callback deletes
 292                          * an event we are still processing.  In that case
 293                          * the data field is set to ENOENT.
 294                          */
 295                         if (events[i].data == EBADF ||
 296                             events[i].data == EINVAL ||
 297                             events[i].data == ENOENT)
 298                                 continue;
 299                         errno = events[i].data;
 300                         return (-1);
 301                 }
 302
 303                 if (events[i].filter == EVFILT_READ) {
 304                         which |= EV_READ;
 305                 } else if (events[i].filter == EVFILT_WRITE) {
 306                         which |= EV_WRITE;
 307                 } else if (events[i].filter == EVFILT_SIGNAL) {
 308                         which |= EV_SIGNAL;
 309                 }
 310
 311                 if (!which)
 312                         continue;
 313
 314                 if (events[i].filter == EVFILT_SIGNAL) {
 315                         evmap_signal_active(base, events[i].ident, 1);
 316                 } else {
 317                         evmap_io_active(base, events[i].ident, which | EV_ET);
 318                 }
 319         }
 320
 321         if (res == kqop->events_size) {
 322                 struct kevent *newresult;
 323                 int size = kqop->events_size;
 324                 /* We used all the events space that we have. Maybe we should
 325                    make it bigger. */
 326                 size *= 2;
 327                 newresult = mm_realloc(kqop->events,
 328                     size * sizeof(struct kevent));
 329                 if (newresult) {
 330                         kqop->events = newresult;
 331                         kqop->events_size = size;
 332                 }
 333         }
 334
 335         return (0);
 336 }
 337
 338 static void
 339 kqop_free(struct kqop *kqop)
 340 {
 341         if (kqop->changes)
 342                 mm_free(kqop->changes);
 343         if (kqop->events)
 344                 mm_free(kqop->events);
 345         if (kqop->kq >= 0 && kqop->pid == getpid())
 346                 close(kqop->kq);
 347         memset(kqop, 0, sizeof(struct kqop));
 348         mm_free(kqop);
 349 }
 350
 351 static void
 352 kq_dealloc(struct event_base *base)
 353 {
 354         struct kqop *kqop = base->evbase;
 355         evsig_dealloc(base);
 356         kqop_free(kqop);
 357 }
 358
 359 /* signal handling */
 360 static int
 361 kq_sig_add(struct event_base *base, int nsignal, short old, short events, void *p)
 362 {
 363         struct kqop *kqop = base->evbase;
 364         struct kevent kev;
 365         struct timespec timeout = { 0, 0 };
 366         (void)p;
 367
 368         EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
 369
 370         memset(&kev, 0, sizeof(kev));
 371         kev.ident = nsignal;
 372         kev.filter = EVFILT_SIGNAL;
 373         kev.flags = EV_ADD;
 374
 375         /* Be ready for the signal if it is sent any
 376          * time between now and the next call to
 377          * kq_dispatch. */
 378         if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
 379                 return (-1);
 380
 381         /* XXXX The manpage suggest we could use SIG_IGN instead of a
 382          * do-nothing handler */
 383         if (_evsig_set_handler(base, nsignal, kq_sighandler) == -1)
 384                 return (-1);
 385
 386         return (0);
 387 }
 388
 389 static int
 390 kq_sig_del(struct event_base *base, int nsignal, short old, short events, void *p)
 391 {
 392         struct kqop *kqop = base->evbase;
 393         struct kevent kev;
 394
 395         struct timespec timeout = { 0, 0 };
 396         (void)p;
 397
 398         EVUTIL_ASSERT(nsignal >= 0 && nsignal < NSIG);
 399
 400         memset(&kev, 0, sizeof(kev));
 401         kev.ident = nsignal;
 402         kev.filter = EVFILT_SIGNAL;
 403         kev.flags = EV_DELETE;
 404
 405         /* Because we insert signal events
 406          * immediately, we need to delete them
 407          * immediately, too */
 408         if (kevent(kqop->kq, &kev, 1, NULL, 0, &timeout) == -1)
 409                 return (-1);
 410
 411         if (_evsig_restore_handler(base, nsignal) == -1)
 412                 return (-1);
 413
 414         return (0);
 415 }