src/event.c

   1 /*
   2     event.c -- I/O, timeout and signal event handling
   3     Copyright (C) 2012-2013 Guus Sliepen <guus@tinc-vpn.org>
   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 "utils.h"
  26
  27 struct timeval now;
  28
  29 static fd_set readfds;
  30 static fd_set writefds;
  31 static volatile bool running;
  32
  33 static int io_compare(const io_t *a, const io_t *b) {
  34         return a->fd - b->fd;
  35 }
  36
  37 static int timeout_compare(const timeout_t *a, const timeout_t *b) {
  38         struct timeval diff;
  39         timersub(&a->tv, &b->tv, &diff);
  40         if(diff.tv_sec < 0)
  41                 return -1;
  42         if(diff.tv_sec > 0)
  43                 return 1;
  44         if(diff.tv_usec < 0)
  45                 return -1;
  46         if(diff.tv_usec > 0)
  47                 return 1;
  48         if(a < b)
  49                 return -1;
  50         if(a > b)
  51                 return 1;
  52         return 0;
  53 }
  54
  55 static splay_tree_t io_tree = {.compare = (splay_compare_t)io_compare};
  56 static splay_tree_t timeout_tree = {.compare = (splay_compare_t)timeout_compare};
  57
  58 void io_add(io_t *io, io_cb_t cb, void *data, int fd, int flags) {
  59         if(io->cb)
  60                 return;
  61
  62         io->fd = fd;
  63         io->cb = cb;
  64         io->data = data;
  65         io->node.data = io;
  66
  67         io_set(io, flags);
  68
  69         if(!splay_insert_node(&io_tree, &io->node))
  70                 abort();
  71 }
  72
  73 void io_set(io_t *io, int flags) {
  74         io->flags = flags;
  75
  76         if(flags & IO_READ)
  77                 FD_SET(io->fd, &readfds);
  78         else
  79                 FD_CLR(io->fd, &readfds);
  80
  81         if(flags & IO_WRITE)
  82                 FD_SET(io->fd, &writefds);
  83         else
  84                 FD_CLR(io->fd, &writefds);
  85 }
  86
  87 void io_del(io_t *io) {
  88         if(!io->cb)
  89                 return;
  90
  91         io_set(io, 0);
  92
  93         splay_unlink_node(&io_tree, &io->node);
  94         io->cb = NULL;
  95 }
  96
  97 void timeout_add(timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
  98         timeout->cb = cb;
  99         timeout->data = data;
 100         timeout->node.data = timeout;
 101
 102         timeout_set(timeout, tv);
 103 }
 104
 105 void timeout_set(timeout_t *timeout, struct timeval *tv) {
 106         if(timerisset(&timeout->tv))
 107                 splay_unlink_node(&timeout_tree, &timeout->node);
 108
 109         if(!now.tv_sec)
 110                 gettimeofday(&now, NULL);
 111
 112         timeradd(&now, tv, &timeout->tv);
 113
 114         if(!splay_insert_node(&timeout_tree, &timeout->node))
 115                 abort();
 116 }
 117
 118 void timeout_del(timeout_t *timeout) {
 119         if(!timeout->cb)
 120                 return;
 121
 122         splay_unlink_node(&timeout_tree, &timeout->node);
 123         timeout->cb = 0;
 124         timeout->tv = (struct timeval){0, 0};
 125 }
 126
 127 #ifndef HAVE_MINGW
 128 static int signal_compare(const signal_t *a, const signal_t *b) {
 129         return a->signum - b->signum;
 130 }
 131
 132 static io_t signalio;
 133 static int pipefd[2] = {-1, -1};
 134 static splay_tree_t signal_tree = {.compare = (splay_compare_t)signal_compare};
 135
 136 static void signal_handler(int signum) {
 137         unsigned char num = signum;
 138         write(pipefd[1], &num, 1);
 139 }
 140
 141 static void signalio_handler(void *data, int flags) {
 142         unsigned char signum;
 143         if(read(pipefd[0], &signum, 1) != 1)
 144                 return;
 145
 146         signal_t *sig = splay_search(&signal_tree, &((signal_t){.signum = signum}));
 147         if(sig)
 148                 sig->cb(sig->data);
 149 }
 150
 151 static void pipe_init(void) {
 152         if(!pipe(pipefd))
 153                 io_add(&signalio, signalio_handler, NULL, pipefd[0], IO_READ);
 154 }
 155
 156 void signal_add(signal_t *sig, signal_cb_t cb, void *data, int signum) {
 157         if(sig->cb)
 158                 return;
 159
 160         sig->cb = cb;
 161         sig->data = data;
 162         sig->signum = signum;
 163         sig->node.data = sig;
 164
 165         if(pipefd[0] == -1)
 166                 pipe_init();
 167
 168         signal(sig->signum, signal_handler);
 169
 170         if(!splay_insert_node(&signal_tree, &sig->node))
 171                 abort();
 172 }
 173
 174 void signal_del(signal_t *sig) {
 175         if(!sig->cb)
 176                 return;
 177
 178         signal(sig->signum, SIG_DFL);
 179
 180         splay_unlink_node(&signal_tree, &sig->node);
 181         sig->cb = NULL;
 182 }
 183 #endif
 184
 185 bool event_loop(void) {
 186         running = true;
 187
 188         fd_set readable;
 189         fd_set writable;
 190
 191         while(running) {
 192                 gettimeofday(&now, NULL);
 193                 struct timeval diff, *tv = NULL;
 194
 195                 while(timeout_tree.head) {
 196                         timeout_t *timeout = timeout_tree.head->data;
 197                         timersub(&timeout->tv, &now, &diff);
 198
 199                         if(diff.tv_sec < 0) {
 200                                 timeout->cb(timeout->data);
 201                                 if(timercmp(&timeout->tv, &now, <))
 202                                         timeout_del(timeout);
 203                         } else {
 204                                 tv = &diff;
 205                                 break;
 206                         }
 207                 }
 208
 209                 memcpy(&readable, &readfds, sizeof readable);
 210                 memcpy(&writable, &writefds, sizeof writable);
 211
 212                 int fds = 0;
 213
 214                 if(io_tree.tail) {
 215                         io_t *last = io_tree.tail->data;
 216                         fds = last->fd + 1;
 217                 }
 218
 219 #ifdef HAVE_MINGW
 220                 LeaveCriticalSection(&mutex);
 221 #endif
 222                 int n = select(fds, &readable, &writable, NULL, tv);
 223 #ifdef HAVE_MINGW
 224                 EnterCriticalSection(&mutex);
 225 #endif
 226
 227                 if(n < 0) {
 228                         if(sockwouldblock(errno))
 229                                 continue;
 230                         else
 231                                 return false;
 232                 }
 233
 234                 if(!n)
 235                         continue;
 236
 237                 for splay_each(io_t, io, &io_tree) {
 238                         if(FD_ISSET(io->fd, &writable))
 239                                 io->cb(io->data, IO_WRITE);
 240                         else if(FD_ISSET(io->fd, &readable))
 241                                 io->cb(io->data, IO_READ);
 242                 }
 243         }
 244
 245         return true;
 246 }
 247
 248 void event_flush_output(void) {
 249         for splay_each(io_t, io, &io_tree)
 250                 if(FD_ISSET(io->fd, &writefds))
 251                         io->cb(io->data, IO_WRITE);
 252 }
 253
 254 void event_exit(void) {
 255         running = false;
 256 }