--- /dev/null
+/*
+ event.c -- event support for Windows
+ Copyright (C) 2012-2022 Guus Sliepen <guus@tinc-vpn.org>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "../system.h"
+
+#include <assert.h>
+
+#include "../event.h"
+#include "../utils.h"
+#include "../net.h"
+
+static bool running = false;
+static DWORD event_count = 0;
+
+static const long READ_EVENTS = FD_READ | FD_ACCEPT | FD_CLOSE;
+static const long WRITE_EVENTS = FD_WRITE | FD_CONNECT;
+
+void io_add(io_t *io, io_cb_t cb, void *data, int fd, int flags) {
+ if(io->cb) {
+ return;
+ }
+
+ io->fd = fd;
+
+ if(io->fd != -1) {
+ io->event = WSACreateEvent();
+
+ if(io->event == WSA_INVALID_EVENT) {
+ abort();
+ }
+ }
+
+ event_count++;
+
+ io->cb = cb;
+ io->data = data;
+ io->node.data = io;
+
+ io_set(io, flags);
+
+ if(!splay_insert_node(&io_tree, &io->node)) {
+ abort();
+ }
+}
+
+void io_add_event(io_t *io, io_cb_t cb, void *data, WSAEVENT event) {
+ io->event = event;
+ io_add(io, cb, data, -1, 0);
+}
+
+void io_set(io_t *io, int flags) {
+ if(flags == io->flags) {
+ return;
+ }
+
+ io->flags = flags;
+
+ if(io->fd == -1) {
+ return;
+ }
+
+ long events = 0;
+
+ if(flags & IO_WRITE) {
+ events |= WRITE_EVENTS;
+ }
+
+ if(flags & IO_READ) {
+ events |= READ_EVENTS;
+ }
+
+ if(WSAEventSelect(io->fd, io->event, events) != 0) {
+ abort();
+ }
+}
+
+void io_del(io_t *io) {
+ if(!io->cb) {
+ return;
+ }
+
+ io_set(io, 0);
+
+ if(io->fd != -1 && WSACloseEvent(io->event) == FALSE) {
+ abort();
+ }
+
+ event_count--;
+ splay_unlink_node(&io_tree, &io->node);
+ io->cb = NULL;
+}
+
+bool event_loop(void) {
+ running = true;
+
+ assert(WSA_WAIT_EVENT_0 == 0);
+
+ while(running) {
+ struct timeval diff;
+ struct timeval *tv = timeout_execute(&diff);
+ DWORD timeout_ms = tv ? (DWORD)(tv->tv_sec * 1000 + tv->tv_usec / 1000 + 1) : WSA_INFINITE;
+
+ if(!event_count) {
+ Sleep(timeout_ms);
+ continue;
+ }
+
+ /*
+ For some reason, Microsoft decided to make the FD_WRITE event edge-triggered instead of level-triggered,
+ which is the opposite of what select() does. In practice, that means that if a FD_WRITE event triggers,
+ it will never trigger again until a send() returns EWOULDBLOCK. Since the semantics of this event loop
+ is that write events are level-triggered (i.e. they continue firing until the socket is full), we need
+ to emulate these semantics by making sure we fire each IO_WRITE that is still writeable.
+
+ Note that technically FD_CLOSE has the same problem, but it's okay because user code does not rely on
+ this event being fired again if ignored.
+ */
+ unsigned int curgen = io_tree.generation;
+
+ for splay_each(io_t, io, &io_tree) {
+ if(io->flags & IO_WRITE && send(io->fd, NULL, 0, 0) == 0) {
+ io->cb(io->data, IO_WRITE);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+ }
+
+ if(event_count > WSA_MAXIMUM_WAIT_EVENTS) {
+ WSASetLastError(WSA_INVALID_PARAMETER);
+ return(false);
+ }
+
+ WSAEVENT events[WSA_MAXIMUM_WAIT_EVENTS];
+ io_t *io_map[WSA_MAXIMUM_WAIT_EVENTS];
+ DWORD event_index = 0;
+
+ for splay_each(io_t, io, &io_tree) {
+ events[event_index] = io->event;
+ io_map[event_index] = io;
+ event_index++;
+ }
+
+ /*
+ * If the generation number changes due to event addition
+ * or removal by a callback we restart the loop.
+ */
+ curgen = io_tree.generation;
+
+ for(DWORD event_offset = 0; event_offset < event_count;) {
+ DWORD result = WSAWaitForMultipleEvents(event_count - event_offset, &events[event_offset], FALSE, timeout_ms, FALSE);
+
+ if(result == WSA_WAIT_TIMEOUT) {
+ break;
+ }
+
+ if(result >= event_count - event_offset) {
+ return false;
+ }
+
+ /* Look up io in the map by index. */
+ event_index = result + event_offset;
+ io_t *io = io_map[event_index];
+
+ if(io->fd == -1) {
+ io->cb(io->data, 0);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ } else {
+ WSANETWORKEVENTS network_events;
+
+ if(WSAEnumNetworkEvents(io->fd, io->event, &network_events) != 0) {
+ return(false);
+ }
+
+ if(network_events.lNetworkEvents & READ_EVENTS) {
+ io->cb(io->data, IO_READ);
+
+ if(curgen != io_tree.generation) {
+ break;
+ }
+ }
+
+ /*
+ The fd might be available for write too. However, if we already fired the read callback, that
+ callback might have deleted the io (e.g. through terminate_connection()), so we can't fire the
+ write callback here. Instead, we loop back and let the writable io loop above handle it.
+ */
+ }
+
+ /* Continue checking the rest of the events. */
+ event_offset = event_index + 1;
+
+ /* Just poll the next time through. */
+ timeout_ms = 0;
+ }
+ }
+
+ return true;
+}
+
+void event_exit(void) {
+ running = false;
+}
projects / tinc / blobdiff