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 static int io_compare(const io_t *a, const io_t *b) {
  30         return a->fd - b->fd;
  31 }
  32
  33 static int timeout_compare(const timeout_t *a, const timeout_t *b) {
  34         struct timeval diff;
  35         timersub(&a->tv, &b->tv, &diff);
  36
  37         if(diff.tv_sec < 0) {
  38                 return -1;
  39         }
  40
  41         if(diff.tv_sec > 0) {
  42                 return 1;
  43         }
  44
  45         if(diff.tv_usec < 0) {
  46                 return -1;
  47         }
  48
  49         if(diff.tv_usec > 0) {
  50                 return 1;
  51         }
  52
  53         if(a < b) {
  54                 return -1;
  55         }
  56
  57         if(a > b) {
  58                 return 1;
  59         }
  60
  61         return 0;
  62 }
  63
  64 void io_add(event_loop_t *loop, io_t *io, io_cb_t cb, void *data, int fd, int flags) {
  65         assert(!io->cb);
  66
  67         io->fd = fd;
  68         io->cb = cb;
  69         io->data = data;
  70         io->node.data = io;
  71
  72         io_set(loop, io, flags);
  73
  74         splay_node_t *node = splay_insert_node(&loop->ios, &io->node);
  75         assert(node);
  76         (void)node;
  77 }
  78
  79 void io_set(event_loop_t *loop, io_t *io, int flags) {
  80         assert(io->cb);
  81
  82         io->flags = flags;
  83
  84         if(flags & IO_READ) {
  85                 FD_SET(io->fd, &loop->readfds);
  86         } else {
  87                 FD_CLR(io->fd, &loop->readfds);
  88         }
  89
  90         if(flags & IO_WRITE) {
  91                 FD_SET(io->fd, &loop->writefds);
  92         } else {
  93                 FD_CLR(io->fd, &loop->writefds);
  94         }
  95 }
  96
  97 void io_del(event_loop_t *loop, io_t *io) {
  98         assert(io->cb);
  99
 100         loop->deletion = true;
 101
 102         io_set(loop, io, 0);
 103
 104         splay_unlink_node(&loop->ios, &io->node);
 105         io->cb = NULL;
 106 }
 107
 108 void timeout_add(event_loop_t *loop, timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
 109         timeout->cb = cb;
 110         timeout->data = data;
 111         timeout->node.data = timeout;
 112
 113         timeout_set(loop, timeout, tv);
 114 }
 115
 116 void timeout_set(event_loop_t *loop, timeout_t *timeout, struct timeval *tv) {
 117         assert(timeout->cb);
 118
 119         if(timerisset(&timeout->tv)) {
 120                 splay_unlink_node(&loop->timeouts, &timeout->node);
 121         }
 122
 123         if(!loop->now.tv_sec) {
 124                 gettimeofday(&loop->now, NULL);
 125         }
 126
 127         timeradd(&loop->now, tv, &timeout->tv);
 128
 129         if(!splay_insert_node(&loop->timeouts, &timeout->node)) {
 130                 abort();
 131         }
 132
 133         loop->deletion = true;
 134 }
 135
 136 static void timeout_disable(event_loop_t *loop, timeout_t *timeout) {
 137         splay_unlink_node(&loop->timeouts, &timeout->node);
 138         timeout->tv = (struct timeval) {
 139                 0, 0
 140         };
 141 }
 142
 143 void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 144         if(!timeout->cb) {
 145                 return;
 146         }
 147
 148         if(timerisset(&timeout->tv)) {
 149                 timeout_disable(loop, timeout);
 150         }
 151
 152         timeout->cb = NULL;
 153         loop->deletion = true;
 154 }
 155
 156 static int signal_compare(const signal_t *a, const signal_t *b) {
 157         return (int)a->signum - (int)b->signum;
 158 }
 159
 160 static void signalio_handler(event_loop_t *loop, void *data, int flags) {
 161         (void)data;
 162         (void)flags;
 163         unsigned char signum;
 164
 165         if(read(loop->pipefd[0], &signum, 1) != 1) {
 166                 return;
 167         }
 168
 169         signal_t *sig = splay_search(&loop->signals, &(signal_t) {
 170                 .signum = signum
 171         });
 172
 173         if(sig) {
 174                 sig->set = false;
 175                 sig->cb(loop, sig->data);
 176         }
 177 }
 178
 179 static void pipe_init(event_loop_t *loop) {
 180         int result = pipe(loop->pipefd);
 181         assert(result == 0);
 182
 183         if(result == 0) {
 184                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 185         }
 186 }
 187
 188 static void pipe_exit(event_loop_t *loop) {
 189         io_del(loop, &loop->signalio);
 190
 191         close(loop->pipefd[0]);
 192         close(loop->pipefd[1]);
 193
 194         loop->pipefd[0] = -1;
 195         loop->pipefd[1] = -1;
 196 }
 197
 198 void signal_trigger(event_loop_t *loop, signal_t *sig) {
 199         if(sig->set) {
 200                 return;
 201         }
 202
 203         uint8_t signum = sig->signum;
 204         sig->set = true;
 205         write(loop->pipefd[1], &signum, 1);
 206         return;
 207 }
 208
 209 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 210         assert(!sig->cb);
 211
 212         sig->cb = cb;
 213         sig->data = data;
 214         sig->signum = signum;
 215         sig->set = false;
 216         sig->node.data = sig;
 217
 218         if(loop->pipefd[0] == -1) {
 219                 pipe_init(loop);
 220         }
 221
 222         if(!splay_insert_node(&loop->signals, &sig->node)) {
 223                 abort();
 224         }
 225 }
 226
 227 void signal_del(event_loop_t *loop, signal_t *sig) {
 228         assert(sig->cb);
 229
 230         loop->deletion = true;
 231
 232         splay_unlink_node(&loop->signals, &sig->node);
 233         sig->cb = NULL;
 234
 235         if(!loop->signals.count && loop->pipefd[0] != -1) {
 236                 pipe_exit(loop);
 237         }
 238 }
 239
 240 void idle_set(event_loop_t *loop, idle_cb_t cb, void *data) {
 241         loop->idle_cb = cb;
 242         loop->idle_data = data;
 243 }
 244
 245 bool event_loop_run(event_loop_t *loop, pthread_mutex_t *mutex) {
 246         assert(mutex);
 247
 248         fd_set readable;
 249         fd_set writable;
 250
 251         while(loop->running) {
 252                 gettimeofday(&loop->now, NULL);
 253                 struct timeval diff, it, *tv = NULL;
 254
 255                 while(loop->timeouts.head) {
 256                         timeout_t *timeout = loop->timeouts.head->data;
 257                         timersub(&timeout->tv, &loop->now, &diff);
 258
 259                         if(diff.tv_sec < 0) {
 260                                 timeout_disable(loop, timeout);
 261                                 timeout->cb(loop, timeout->data);
 262                         } else {
 263                                 tv = &diff;
 264                                 break;
 265                         }
 266                 }
 267
 268                 if(loop->idle_cb) {
 269                         it = loop->idle_cb(loop, loop->idle_data);
 270
 271                         if(it.tv_sec >= 0 && (!tv || timercmp(&it, tv, <))) {
 272                                 tv = &it;
 273                         }
 274                 }
 275
 276                 memcpy(&readable, &loop->readfds, sizeof(readable));
 277                 memcpy(&writable, &loop->writefds, sizeof(writable));
 278
 279                 int fds = 0;
 280
 281                 if(loop->ios.tail) {
 282                         io_t *last = loop->ios.tail->data;
 283                         fds = last->fd + 1;
 284                 }
 285
 286                 // release mesh mutex during select
 287                 pthread_mutex_unlock(mutex);
 288
 289                 int n = select(fds, &readable, &writable, NULL, tv);
 290
 291                 pthread_mutex_lock(mutex);
 292
 293                 gettimeofday(&loop->now, NULL);
 294
 295                 if(n < 0) {
 296                         if(sockwouldblock(errno)) {
 297                                 continue;
 298                         } else {
 299                                 return false;
 300                         }
 301                 }
 302
 303                 if(!n) {
 304                         continue;
 305                 }
 306
 307                 // Normally, splay_each allows the current node to be deleted. However,
 308                 // it can be that one io callback triggers the deletion of another io,
 309                 // so we have to detect this and break the loop.
 310
 311                 loop->deletion = false;
 312
 313                 for splay_each(io_t, io, &loop->ios) {
 314                         if(FD_ISSET(io->fd, &writable) && io->cb) {
 315                                 io->cb(loop, io->data, IO_WRITE);
 316                         }
 317
 318                         if(loop->deletion) {
 319                                 break;
 320                         }
 321
 322                         if(FD_ISSET(io->fd, &readable) && io->cb) {
 323                                 io->cb(loop, io->data, IO_READ);
 324                         }
 325
 326                         if(loop->deletion) {
 327                                 break;
 328                         }
 329                 }
 330         }
 331
 332         return true;
 333 }
 334
 335 void event_flush_output(event_loop_t *loop) {
 336         for splay_each(io_t, io, &loop->ios)
 337                 if(FD_ISSET(io->fd, &loop->writefds)) {
 338                         io->cb(loop, io->data, IO_WRITE);
 339                 }
 340 }
 341
 342 void event_loop_start(event_loop_t *loop) {
 343         loop->running = true;
 344 }
 345
 346 void event_loop_stop(event_loop_t *loop) {
 347         loop->running = false;
 348 }
 349
 350 void event_loop_init(event_loop_t *loop) {
 351         loop->ios.compare = (splay_compare_t)io_compare;
 352         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 353         loop->signals.compare = (splay_compare_t)signal_compare;
 354         loop->pipefd[0] = -1;
 355         loop->pipefd[1] = -1;
 356         gettimeofday(&loop->now, NULL);
 357 }
 358
 359 void event_loop_exit(event_loop_t *loop) {
 360         assert(!loop->ios.count);
 361         assert(!loop->timeouts.count);
 362         assert(!loop->signals.count);
 363
 364         for splay_each(io_t, io, &loop->ios) {
 365                 splay_unlink_node(&loop->ios, node);
 366         }
 367
 368         for splay_each(timeout_t, timeout, &loop->timeouts) {
 369                 splay_unlink_node(&loop->timeouts, node);
 370         }
 371
 372         for splay_each(signal_t, signal, &loop->signals) {
 373                 splay_unlink_node(&loop->signals, node);
 374         }
 375 }