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