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