git.meshlink.io Git - meshlink/blob - src/event.c

   1 /*
   2     event.c -- I/O, timeout and signal event handling
   3     Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "dropin.h"
  23 #include "event.h"
  24 #include "net.h"
  25 #include "splay_tree.h"
  26 #include "utils.h"
  27 #include "xalloc.h"
  28
  29 #ifndef EVENT_CLOCK
  30 #if defined(CLOCK_MONOTONIC_RAW) && defined(__x86_64__)
  31 #define EVENT_CLOCK CLOCK_MONOTONIC_RAW
  32 #else
  33 #define EVENT_CLOCK CLOCK_MONOTONIC
  34 #endif
  35 #endif
  36
  37 static void timespec_add(const struct timespec *a, const struct timespec *b, struct timespec *r) {
  38         r->tv_sec = a->tv_sec + b->tv_sec;
  39         r->tv_nsec = a->tv_nsec + b->tv_nsec;
  40
  41         if(r->tv_nsec > 1000000000) {
  42                 r->tv_sec++, r->tv_nsec -= 1000000000;
  43         }
  44 }
  45
  46 static void timespec_sub(const struct timespec *a, const struct timespec *b, struct timespec *r) {
  47         r->tv_sec = a->tv_sec - b->tv_sec;
  48         r->tv_nsec = a->tv_nsec - b->tv_nsec;
  49
  50         if(r->tv_nsec < 0) {
  51                 r->tv_sec--, r->tv_nsec += 1000000000;
  52         }
  53 }
  54
  55 static bool timespec_lt(const struct timespec *a, const struct timespec *b) {
  56         if(a->tv_sec == b->tv_sec) {
  57                 return a->tv_nsec < b->tv_nsec;
  58         } else {
  59                 return a->tv_sec < b->tv_sec;
  60         }
  61 }
  62
  63 static void timespec_clear(struct timespec *a) {
  64         a->tv_sec = 0;
  65 }
  66
  67 static int io_compare(const io_t *a, const io_t *b) {
  68         return a->fd - b->fd;
  69 }
  70
  71 static int timeout_compare(const timeout_t *a, const timeout_t *b) {
  72         if(a->tv.tv_sec < b->tv.tv_sec) {
  73                 return -1;
  74         } else if(a->tv.tv_sec > b->tv.tv_sec) {
  75                 return 1;
  76         } else if(a->tv.tv_nsec < b->tv.tv_nsec) {
  77                 return -1;
  78         } else if(a->tv.tv_nsec > b->tv.tv_nsec) {
  79                 return 1;
  80         } else if(a < b) {
  81                 return -1;
  82         } else if(a > b) {
  83                 return 1;
  84         } else {
  85                 return 0;
  86         }
  87 }
  88
  89 void io_add(event_loop_t *loop, io_t *io, io_cb_t cb, void *data, int fd, int flags) {
  90         assert(!io->cb);
  91
  92         io->fd = fd;
  93         io->cb = cb;
  94         io->data = data;
  95         io->node.data = io;
  96
  97         io_set(loop, io, flags);
  98
  99         splay_node_t *node = splay_insert_node(&loop->ios, &io->node);
 100         assert(node);
 101         (void)node;
 102 }
 103
 104 void io_set(event_loop_t *loop, io_t *io, int flags) {
 105         assert(io->cb);
 106
 107         io->flags = flags;
 108
 109         if(flags & IO_READ) {
 110                 FD_SET(io->fd, &loop->readfds);
 111         } else {
 112                 FD_CLR(io->fd, &loop->readfds);
 113         }
 114
 115         if(flags & IO_WRITE) {
 116                 FD_SET(io->fd, &loop->writefds);
 117         } else {
 118                 FD_CLR(io->fd, &loop->writefds);
 119         }
 120 }
 121
 122 void io_del(event_loop_t *loop, io_t *io) {
 123         assert(io->cb);
 124
 125         loop->deletion = true;
 126
 127         io_set(loop, io, 0);
 128
 129         splay_unlink_node(&loop->ios, &io->node);
 130         io->cb = NULL;
 131 }
 132
 133 void timeout_add(event_loop_t *loop, timeout_t *timeout, timeout_cb_t cb, void *data, struct timespec *tv) {
 134         timeout->cb = cb;
 135         timeout->data = data;
 136
 137         timeout_set(loop, timeout, tv);
 138 }
 139
 140 void timeout_set(event_loop_t *loop, timeout_t *timeout, struct timespec *tv) {
 141         assert(timeout->cb);
 142
 143         if(timeout->node.data) {
 144                 splay_unlink_node(&loop->timeouts, &timeout->node);
 145         } else {
 146                 timeout->node.data = timeout;
 147         }
 148
 149         if(!loop->now.tv_sec) {
 150                 clock_gettime(EVENT_CLOCK, &loop->now);
 151         }
 152
 153         timespec_add(&loop->now, tv, &timeout->tv);
 154
 155         if(!splay_insert_node(&loop->timeouts, &timeout->node)) {
 156                 abort();
 157         }
 158
 159         loop->deletion = true;
 160 }
 161
 162 static void timeout_disable(event_loop_t *loop, timeout_t *timeout) {
 163         if(timeout->node.data) {
 164                 splay_unlink_node(&loop->timeouts, &timeout->node);
 165                 timeout->node.data = NULL;
 166         }
 167
 168         timespec_clear(&timeout->tv);
 169 }
 170
 171 void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 172         if(!timeout->cb) {
 173                 return;
 174         }
 175
 176         if(timeout->node.data) {
 177                 timeout_disable(loop, timeout);
 178         }
 179
 180         timeout->cb = NULL;
 181         loop->deletion = true;
 182 }
 183
 184 static int signal_compare(const signal_t *a, const signal_t *b) {
 185         return (int)a->signum - (int)b->signum;
 186 }
 187
 188 static void signalio_handler(event_loop_t *loop, void *data, int flags) {
 189         (void)data;
 190         (void)flags;
 191         unsigned char signum;
 192
 193         if(read(loop->pipefd[0], &signum, 1) != 1) {
 194                 return;
 195         }
 196
 197         signal_t *sig = splay_search(&loop->signals, &(signal_t) {
 198                 .signum = signum
 199         });
 200
 201         if(sig) {
 202 #ifdef HAVE_STDATOMIC_H
 203                 atomic_flag_clear(&sig->set);
 204 #endif
 205                 sig->cb(loop, sig->data);
 206         }
 207 }
 208
 209 static void pipe_init(event_loop_t *loop) {
 210         int result = pipe(loop->pipefd);
 211         assert(result == 0);
 212
 213         if(result == 0) {
 214 #ifdef O_NONBLOCK
 215                 fcntl(loop->pipefd[0], F_SETFL, O_NONBLOCK);
 216                 fcntl(loop->pipefd[1], F_SETFL, O_NONBLOCK);
 217 #endif
 218                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 219         }
 220 }
 221
 222 static void pipe_exit(event_loop_t *loop) {
 223         io_del(loop, &loop->signalio);
 224
 225         close(loop->pipefd[0]);
 226         close(loop->pipefd[1]);
 227
 228         loop->pipefd[0] = -1;
 229         loop->pipefd[1] = -1;
 230 }
 231
 232 void signal_trigger(event_loop_t *loop, signal_t *sig) {
 233 #ifdef HAVE_STDATOMIC_H
 234
 235         if(atomic_flag_test_and_set(&sig->set)) {
 236                 return;
 237         }
 238
 239 #endif
 240
 241         uint8_t signum = sig->signum;
 242         write(loop->pipefd[1], &signum, 1);
 243         return;
 244 }
 245
 246 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 247         assert(!sig->cb);
 248
 249         sig->cb = cb;
 250         sig->data = data;
 251         sig->signum = signum;
 252         sig->node.data = sig;
 253
 254 #ifdef HAVE_STDATOMIC_H
 255         atomic_flag_clear(&sig->set);
 256 #endif
 257
 258         if(loop->pipefd[0] == -1) {
 259                 pipe_init(loop);
 260         }
 261
 262         if(!splay_insert_node(&loop->signals, &sig->node)) {
 263                 abort();
 264         }
 265 }
 266
 267 void signal_del(event_loop_t *loop, signal_t *sig) {
 268         assert(sig->cb);
 269
 270         loop->deletion = true;
 271
 272         splay_unlink_node(&loop->signals, &sig->node);
 273         sig->cb = NULL;
 274
 275         if(!loop->signals.count && loop->pipefd[0] != -1) {
 276                 pipe_exit(loop);
 277         }
 278 }
 279
 280 void idle_set(event_loop_t *loop, idle_cb_t cb, void *data) {
 281         loop->idle_cb = cb;
 282         loop->idle_data = data;
 283 }
 284
 285 static void check_bad_fds(event_loop_t *loop) {
 286         // Just call all registered callbacks and have them check their fds
 287
 288         do {
 289                 loop->deletion = false;
 290
 291                 for splay_each(io_t, io, &loop->ios) {
 292                         if(io->flags & IO_WRITE) {
 293                                 io->cb(loop, io->data, IO_WRITE);
 294                         }
 295
 296                         if(loop->deletion) {
 297                                 break;
 298                         }
 299
 300                         if(io->flags & IO_READ) {
 301                                 io->cb(loop, io->data, IO_READ);
 302                         }
 303
 304                         if(loop->deletion) {
 305                                 break;
 306                         }
 307                 }
 308         } while(loop->deletion);
 309
 310         // Rebuild the fdsets
 311
 312         memset(&loop->readfds, 0, sizeof(loop->readfds));
 313         memset(&loop->writefds, 0, sizeof(loop->writefds));
 314
 315         for splay_each(io_t, io, &loop->ios) {
 316                 if(io->flags & IO_READ) {
 317                         FD_SET(io->fd, &loop->readfds);
 318                         io->cb(loop, io->data, IO_READ);
 319                 }
 320
 321                 if(io->flags & IO_WRITE) {
 322                         FD_SET(io->fd, &loop->writefds);
 323                         io->cb(loop, io->data, IO_WRITE);
 324                 }
 325
 326         }
 327 }
 328
 329 bool event_loop_run(event_loop_t *loop, pthread_mutex_t *mutex) {
 330         assert(mutex);
 331
 332         fd_set readable;
 333         fd_set writable;
 334         int errors = 0;
 335
 336         while(loop->running) {
 337                 clock_gettime(EVENT_CLOCK, &loop->now);
 338                 struct timespec it, ts = {3600, 0};
 339
 340                 while(loop->timeouts.head) {
 341                         timeout_t *timeout = loop->timeouts.head->data;
 342
 343                         if(timespec_lt(&timeout->tv, &loop->now)) {
 344                                 timeout_disable(loop, timeout);
 345                                 timeout->cb(loop, timeout->data);
 346                         } else {
 347                                 timespec_sub(&timeout->tv, &loop->now, &ts);
 348                                 break;
 349                         }
 350                 }
 351
 352                 if(loop->idle_cb) {
 353                         it = loop->idle_cb(loop, loop->idle_data);
 354
 355                         if(it.tv_sec >= 0 && timespec_lt(&it, &ts)) {
 356                                 ts = it;
 357                         }
 358                 }
 359
 360                 memcpy(&readable, &loop->readfds, sizeof(readable));
 361                 memcpy(&writable, &loop->writefds, sizeof(writable));
 362
 363                 int fds = 0;
 364
 365                 if(loop->ios.tail) {
 366                         io_t *last = loop->ios.tail->data;
 367                         fds = last->fd + 1;
 368                 }
 369
 370                 // release mesh mutex during select
 371                 pthread_mutex_unlock(mutex);
 372
 373 #ifdef HAVE_PSELECT
 374                 int n = pselect(fds, &readable, &writable, NULL, &ts, NULL);
 375 #else
 376                 struct timeval tv = {ts.tv_sec, ts.tv_nsec / 1000};
 377                 int n = select(fds, &readable, &writable, NULL, (struct timeval *)&tv);
 378 #endif
 379
 380                 if(pthread_mutex_lock(mutex) != 0) {
 381                         abort();
 382                 }
 383
 384                 clock_gettime(EVENT_CLOCK, &loop->now);
 385
 386                 if(n < 0) {
 387                         if(sockwouldblock(errno)) {
 388                                 continue;
 389                         } else {
 390                                 errors++;
 391
 392                                 if(errors > 10) {
 393                                         return false;
 394                                 }
 395
 396                                 check_bad_fds(loop);
 397                                 continue;
 398                         }
 399                 }
 400
 401                 errors = 0;
 402
 403                 if(!n) {
 404                         continue;
 405                 }
 406
 407                 // Normally, splay_each allows the current node to be deleted. However,
 408                 // it can be that one io callback triggers the deletion of another io,
 409                 // so we have to detect this and break the loop.
 410
 411                 loop->deletion = false;
 412
 413                 for splay_each(io_t, io, &loop->ios) {
 414                         if(FD_ISSET(io->fd, &writable) && io->cb) {
 415                                 io->cb(loop, io->data, IO_WRITE);
 416                         }
 417
 418                         if(loop->deletion) {
 419                                 break;
 420                         }
 421
 422                         if(FD_ISSET(io->fd, &readable) && io->cb) {
 423                                 io->cb(loop, io->data, IO_READ);
 424                         }
 425
 426                         if(loop->deletion) {
 427                                 break;
 428                         }
 429                 }
 430         }
 431
 432         return true;
 433 }
 434
 435 void event_loop_start(event_loop_t *loop) {
 436         loop->running = true;
 437 }
 438
 439 void event_loop_stop(event_loop_t *loop) {
 440         loop->running = false;
 441 }
 442
 443 void event_loop_init(event_loop_t *loop) {
 444         loop->ios.compare = (splay_compare_t)io_compare;
 445         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 446         loop->signals.compare = (splay_compare_t)signal_compare;
 447         loop->pipefd[0] = -1;
 448         loop->pipefd[1] = -1;
 449         clock_gettime(EVENT_CLOCK, &loop->now);
 450 }
 451
 452 void event_loop_exit(event_loop_t *loop) {
 453         assert(!loop->ios.count);
 454         assert(!loop->timeouts.count);
 455         assert(!loop->signals.count);
 456
 457         for splay_each(io_t, io, &loop->ios) {
 458                 splay_unlink_node(&loop->ios, splay_node);
 459         }
 460
 461         for splay_each(timeout_t, timeout, &loop->timeouts) {
 462                 splay_unlink_node(&loop->timeouts, splay_node);
 463         }
 464
 465         for splay_each(signal_t, signal, &loop->signals) {
 466                 splay_unlink_node(&loop->signals, splay_node);
 467         }
 468 }