2 event.c -- I/O, timeout and signal event handling
3 Copyright (C) 2012-2013 Guus Sliepen <guus@tinc-vpn.org>
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.
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.
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.
31 static fd_set readfds;
32 static fd_set writefds;
34 static const long READ_EVENTS = FD_READ | FD_ACCEPT | FD_CLOSE;
35 static const long WRITE_EVENTS = FD_WRITE | FD_CONNECT;
36 static DWORD event_count = 0;
38 static volatile bool running;
40 static int io_compare(const io_t *a, const io_t *b) {
44 return a->event - b->event;
48 static int timeout_compare(const timeout_t *a, const timeout_t *b) {
50 timersub(&a->tv, &b->tv, &diff);
66 static splay_tree_t io_tree = {.compare = (splay_compare_t)io_compare};
67 static splay_tree_t timeout_tree = {.compare = (splay_compare_t)timeout_compare};
69 void io_add(io_t *io, io_cb_t cb, void *data, int fd, int flags) {
75 io->event = WSACreateEvent();
76 if (io->event == WSA_INVALID_EVENT)
86 if(!splay_insert_node(&io_tree, &io->node))
90 void io_set(io_t *io, int flags) {
91 if (flags == io->flags)
97 FD_SET(io->fd, &readfds);
99 FD_CLR(io->fd, &readfds);
102 FD_SET(io->fd, &writefds);
104 FD_CLR(io->fd, &writefds);
107 if (flags & IO_WRITE)
108 events |= WRITE_EVENTS;
110 events |= READ_EVENTS;
111 if (WSAEventSelect(io->fd, io->event, events) != 0)
116 void io_del(io_t *io) {
122 if (WSACloseEvent(io->event) == FALSE)
127 splay_unlink_node(&io_tree, &io->node);
131 void timeout_add(timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
133 timeout->data = data;
134 timeout->node.data = timeout;
136 timeout_set(timeout, tv);
139 void timeout_set(timeout_t *timeout, struct timeval *tv) {
140 if(timerisset(&timeout->tv))
141 splay_unlink_node(&timeout_tree, &timeout->node);
144 gettimeofday(&now, NULL);
146 timeradd(&now, tv, &timeout->tv);
148 if(!splay_insert_node(&timeout_tree, &timeout->node))
152 void timeout_del(timeout_t *timeout) {
156 splay_unlink_node(&timeout_tree, &timeout->node);
158 timeout->tv = (struct timeval){0, 0};
162 static int signal_compare(const signal_t *a, const signal_t *b) {
163 return a->signum - b->signum;
166 static io_t signalio;
167 static int pipefd[2] = {-1, -1};
168 static splay_tree_t signal_tree = {.compare = (splay_compare_t)signal_compare};
170 static void signal_handler(int signum) {
171 unsigned char num = signum;
172 write(pipefd[1], &num, 1);
175 static void signalio_handler(void *data, int flags) {
176 unsigned char signum;
177 if(read(pipefd[0], &signum, 1) != 1)
180 signal_t *sig = splay_search(&signal_tree, &((signal_t){.signum = signum}));
185 static void pipe_init(void) {
187 io_add(&signalio, signalio_handler, NULL, pipefd[0], IO_READ);
190 void signal_add(signal_t *sig, signal_cb_t cb, void *data, int signum) {
196 sig->signum = signum;
197 sig->node.data = sig;
202 signal(sig->signum, signal_handler);
204 if(!splay_insert_node(&signal_tree, &sig->node))
208 void signal_del(signal_t *sig) {
212 signal(sig->signum, SIG_DFL);
214 splay_unlink_node(&signal_tree, &sig->node);
219 static struct timeval * get_time_remaining(struct timeval *diff) {
220 gettimeofday(&now, NULL);
221 struct timeval *tv = NULL;
223 while(timeout_tree.head) {
224 timeout_t *timeout = timeout_tree.head->data;
225 timersub(&timeout->tv, &now, diff);
227 if(diff->tv_sec < 0) {
228 timeout->cb(timeout->data);
229 if(timercmp(&timeout->tv, &now, <))
230 timeout_del(timeout);
240 bool event_loop(void) {
248 memcpy(&readable, &readfds, sizeof readable);
249 memcpy(&writable, &writefds, sizeof writable);
251 struct timeval *tv = get_time_remaining(&diff);
256 io_t *last = io_tree.tail->data;
260 int n = select(fds, &readable, &writable, NULL, tv);
263 if(sockwouldblock(sockerrno))
272 for splay_each(io_t, io, &io_tree) {
273 if(FD_ISSET(io->fd, &writable))
274 io->cb(io->data, IO_WRITE);
275 else if(FD_ISSET(io->fd, &readable))
276 io->cb(io->data, IO_READ);
282 struct timeval *tv = get_time_remaining(&diff);
283 DWORD timeout_ms = tv ? (tv->tv_sec * 1000 + tv->tv_usec / 1000 + 1) : WSA_INFINITE;
286 LeaveCriticalSection(&mutex);
288 EnterCriticalSection(&mutex);
293 For some reason, Microsoft decided to make the FD_WRITE event edge-triggered instead of level-triggered,
294 which is the opposite of what select() does. In practice, that means that if a FD_WRITE event triggers,
295 it will never trigger again until a send() returns EWOULDBLOCK. Since the semantics of this event loop
296 is that write events are level-triggered (i.e. they continue firing until the socket is full), we need
297 to emulate these semantics by making sure we fire each IO_WRITE that is still writeable.
299 Note that technically FD_CLOSE has the same problem, but it's okay because user code does not rely on
300 this event being fired again if ignored.
302 io_t* writeable_io = NULL;
303 for splay_each(io_t, io, &io_tree)
304 if (io->flags & IO_WRITE && send(io->fd, NULL, 0, 0) == 0) {
309 writeable_io->cb(writeable_io->data, IO_WRITE);
313 WSAEVENT* events = xmalloc(event_count * sizeof(*events));
314 DWORD event_index = 0;
315 for splay_each(io_t, io, &io_tree) {
316 events[event_index] = io->event;
320 LeaveCriticalSection(&mutex);
321 DWORD result = WSAWaitForMultipleEvents(event_count, events, FALSE, timeout_ms, FALSE);
322 EnterCriticalSection(&mutex);
325 if (result >= WSA_WAIT_EVENT_0 && result < WSA_WAIT_EVENT_0 + event_count)
326 event = events[result - WSA_WAIT_EVENT_0];
328 if (result == WSA_WAIT_TIMEOUT)
330 if (result < WSA_WAIT_EVENT_0 || result >= WSA_WAIT_EVENT_0 + event_count)
333 io_t *io = splay_search(&io_tree, &((io_t){.event = event}));
337 WSANETWORKEVENTS network_events;
338 if (WSAEnumNetworkEvents(io->fd, io->event, &network_events) != 0)
340 if (network_events.lNetworkEvents & WRITE_EVENTS)
341 io->cb(io->data, IO_WRITE);
342 if (network_events.lNetworkEvents & READ_EVENTS)
343 io->cb(io->data, IO_READ);
350 void event_flush_output(void) {
351 for splay_each(io_t, io, &io_tree)
352 if(io->flags & IO_WRITE)
353 io->cb(io->data, IO_WRITE);
356 void event_exit(void) {