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->cb(loop, sig->data);
 175         }
 176 }
 177
 178 static void pipe_init(event_loop_t *loop) {
 179         int result = pipe(loop->pipefd);
 180         assert(result == 0);
 181
 182         if(result == 0) {
 183                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 184         }
 185 }
 186
 187 static void pipe_exit(event_loop_t *loop) {
 188         io_del(loop, &loop->signalio);
 189
 190         close(loop->pipefd[0]);
 191         close(loop->pipefd[1]);
 192
 193         loop->pipefd[0] = -1;
 194         loop->pipefd[1] = -1;
 195 }
 196
 197 void signal_trigger(event_loop_t *loop, signal_t *sig) {
 198         uint8_t signum = sig->signum;
 199         write(loop->pipefd[1], &signum, 1);
 200         return;
 201 }
 202
 203 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 204         assert(!sig->cb);
 205
 206         sig->cb = cb;
 207         sig->data = data;
 208         sig->signum = signum;
 209         sig->node.data = sig;
 210
 211         if(loop->pipefd[0] == -1) {
 212                 pipe_init(loop);
 213         }
 214
 215         if(!splay_insert_node(&loop->signals, &sig->node)) {
 216                 abort();
 217         }
 218 }
 219
 220 void signal_del(event_loop_t *loop, signal_t *sig) {
 221         assert(sig->cb);
 222
 223         loop->deletion = true;
 224
 225         splay_unlink_node(&loop->signals, &sig->node);
 226         sig->cb = NULL;
 227
 228         if(!loop->signals.count && loop->pipefd[0] != -1) {
 229                 pipe_exit(loop);
 230         }
 231 }
 232
 233 void idle_set(event_loop_t *loop, idle_cb_t cb, void *data) {
 234         loop->idle_cb = cb;
 235         loop->idle_data = data;
 236 }
 237
 238 bool event_loop_run(event_loop_t *loop, pthread_mutex_t *mutex) {
 239         assert(mutex);
 240
 241         fd_set readable;
 242         fd_set writable;
 243
 244         while(loop->running) {
 245                 gettimeofday(&loop->now, NULL);
 246                 struct timeval diff, it, *tv = NULL;
 247
 248                 while(loop->timeouts.head) {
 249                         timeout_t *timeout = loop->timeouts.head->data;
 250                         timersub(&timeout->tv, &loop->now, &diff);
 251
 252                         if(diff.tv_sec < 0) {
 253                                 timeout_disable(loop, timeout);
 254                                 timeout->cb(loop, timeout->data);
 255                         } else {
 256                                 tv = &diff;
 257                                 break;
 258                         }
 259                 }
 260
 261                 if(loop->idle_cb) {
 262                         it = loop->idle_cb(loop, loop->idle_data);
 263
 264                         if(it.tv_sec >= 0 && (!tv || timercmp(&it, tv, <))) {
 265                                 tv = &it;
 266                         }
 267                 }
 268
 269                 memcpy(&readable, &loop->readfds, sizeof(readable));
 270                 memcpy(&writable, &loop->writefds, sizeof(writable));
 271
 272                 int fds = 0;
 273
 274                 if(loop->ios.tail) {
 275                         io_t *last = loop->ios.tail->data;
 276                         fds = last->fd + 1;
 277                 }
 278
 279                 // release mesh mutex during select
 280                 pthread_mutex_unlock(mutex);
 281
 282                 int n = select(fds, &readable, &writable, NULL, tv);
 283
 284                 pthread_mutex_lock(mutex);
 285
 286                 gettimeofday(&loop->now, NULL);
 287
 288                 if(n < 0) {
 289                         if(sockwouldblock(errno)) {
 290                                 continue;
 291                         } else {
 292                                 return false;
 293                         }
 294                 }
 295
 296                 if(!n) {
 297                         continue;
 298                 }
 299
 300                 // Normally, splay_each allows the current node to be deleted. However,
 301                 // it can be that one io callback triggers the deletion of another io,
 302                 // so we have to detect this and break the loop.
 303
 304                 loop->deletion = false;
 305
 306                 for splay_each(io_t, io, &loop->ios) {
 307                         if(FD_ISSET(io->fd, &writable) && io->cb) {
 308                                 io->cb(loop, io->data, IO_WRITE);
 309                         }
 310
 311                         if(loop->deletion) {
 312                                 break;
 313                         }
 314
 315                         if(FD_ISSET(io->fd, &readable) && io->cb) {
 316                                 io->cb(loop, io->data, IO_READ);
 317                         }
 318
 319                         if(loop->deletion) {
 320                                 break;
 321                         }
 322                 }
 323         }
 324
 325         return true;
 326 }
 327
 328 void event_flush_output(event_loop_t *loop) {
 329         for splay_each(io_t, io, &loop->ios)
 330                 if(FD_ISSET(io->fd, &loop->writefds)) {
 331                         io->cb(loop, io->data, IO_WRITE);
 332                 }
 333 }
 334
 335 void event_loop_start(event_loop_t *loop) {
 336         loop->running = true;
 337 }
 338
 339 void event_loop_stop(event_loop_t *loop) {
 340         loop->running = false;
 341 }
 342
 343 void event_loop_init(event_loop_t *loop) {
 344         loop->ios.compare = (splay_compare_t)io_compare;
 345         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 346         loop->signals.compare = (splay_compare_t)signal_compare;
 347         loop->pipefd[0] = -1;
 348         loop->pipefd[1] = -1;
 349         gettimeofday(&loop->now, NULL);
 350 }
 351
 352 void event_loop_exit(event_loop_t *loop) {
 353         assert(!loop->ios.count);
 354         assert(!loop->timeouts.count);
 355         assert(!loop->signals.count);
 356
 357         for splay_each(io_t, io, &loop->ios) {
 358                 splay_unlink_node(&loop->ios, node);
 359         }
 360
 361         for splay_each(timeout_t, timeout, &loop->timeouts) {
 362                 splay_unlink_node(&loop->timeouts, node);
 363         }
 364
 365         for splay_each(signal_t, signal, &loop->signals) {
 366                 splay_unlink_node(&loop->signals, node);
 367         }
 368 }