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#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include <assert.h>
#include "red_common.h"
#include "main_dispatcher.h"
/*
* Main Dispatcher
* ===============
*
* Communication channel between any non main thread and the main thread.
*
* The main thread is that from which spice_server_init is called.
*
* Messages are single sized, sent from the non-main thread to the main-thread.
* No acknowledge is sent back. This prevents a possible deadlock with the main
* thread already waiting on a response for the existing red_dispatcher used
* by the worker thread.
*
* All events have three functions:
* main_dispatcher_<event_name> - non static, public function
* main_dispatcher_self_<event_name> - handler for main thread
* main_dispatcher_handle_<event_name> - handler for callback from main thread
* seperate from self because it may send an ack or do other work in the future.
*/
typedef struct {
SpiceCoreInterface *core;
int main_fd;
int other_fd;
pthread_t self;
pthread_mutex_t lock;
} MainDispatcher;
MainDispatcher main_dispatcher;
enum {
MAIN_DISPATCHER_CHANNEL_EVENT = 0,
MAIN_DISPATCHER_NUM_MESSAGES
};
typedef struct MainDispatcherMessage {
uint32_t type;
union {
struct {
int event;
SpiceChannelEventInfo *info;
} channel_event;
} data;
} MainDispatcherMessage;
/* channel_event - calls core->channel_event, must be done in main thread */
static void main_dispatcher_self_handle_channel_event(
int event,
SpiceChannelEventInfo *info)
{
main_dispatcher.core->channel_event(event, info);
}
static void main_dispatcher_handle_channel_event(MainDispatcherMessage *msg)
{
main_dispatcher_self_handle_channel_event(msg->data.channel_event.event,
msg->data.channel_event.info);
}
void main_dispatcher_channel_event(int event, SpiceChannelEventInfo *info)
{
MainDispatcherMessage msg;
ssize_t written = 0;
ssize_t ret;
if (pthread_self() == main_dispatcher.self) {
main_dispatcher_self_handle_channel_event(event, info);
return;
}
msg.type = MAIN_DISPATCHER_CHANNEL_EVENT;
msg.data.channel_event.event = event;
msg.data.channel_event.info = info;
pthread_mutex_lock(&main_dispatcher.lock);
while (written < sizeof(msg)) {
ret = write(main_dispatcher.other_fd, &msg + written,
sizeof(msg) - written);
if (ret == -1) {
assert(errno == EINTR);
continue;
}
written += ret;
}
pthread_mutex_unlock(&main_dispatcher.lock);
}
static void main_dispatcher_handle_read(int fd, int event, void *opaque)
{
int ret;
MainDispatcher *md = opaque;
MainDispatcherMessage msg;
int read_size = 0;
while (read_size < sizeof(msg)) {
/* blocks until sizeof(msg) is read */
ret = read(md->main_fd, &msg + read_size, sizeof(msg) - read_size);
if (ret == -1) {
if (errno != EINTR) {
red_printf("error reading from main dispatcher: %d\n", errno);
/* TODO: close channel? */
return;
}
continue;
}
read_size += ret;
}
switch (msg.type) {
case MAIN_DISPATCHER_CHANNEL_EVENT:
main_dispatcher_handle_channel_event(&msg);
break;
default:
red_printf("error: unhandled main dispatcher message type %d\n",
msg.type);
}
}
void main_dispatcher_init(SpiceCoreInterface *core)
{
int channels[2];
memset(&main_dispatcher, 0, sizeof(main_dispatcher));
main_dispatcher.core = core;
if (socketpair(AF_LOCAL, SOCK_STREAM, 0, channels) == -1) {
red_error("socketpair failed %s", strerror(errno));
return;
}
pthread_mutex_init(&main_dispatcher.lock, NULL);
main_dispatcher.main_fd = channels[0];
main_dispatcher.other_fd = channels[1];
main_dispatcher.self = pthread_self();
core->watch_add(main_dispatcher.main_fd, SPICE_WATCH_EVENT_READ,
main_dispatcher_handle_read, &main_dispatcher);
}
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