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