xenocara/xserver/config/dbus-core.c

247 lines
7.0 KiB
C

/*
* Copyright © 2006-2007 Daniel Stone
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Author: Daniel Stone <daniel@fooishbar.org>
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include <dbus/dbus.h>
#include <sys/select.h>
#include "config-backends.h"
#include "dix.h"
#include "os.h"
/* How often to attempt reconnecting when we get booted off the bus. */
#define RECONNECT_DELAY (10 * 1000) /* in ms */
struct dbus_core_info {
int fd;
DBusConnection *connection;
OsTimerPtr timer;
struct config_dbus_core_hook *hooks;
};
static struct dbus_core_info bus_info;
static CARD32 reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg);
static void
wakeup_handler(pointer data, int err, pointer read_mask)
{
struct dbus_core_info *info = data;
if (info->connection && FD_ISSET(info->fd, (fd_set *) read_mask)) {
do {
dbus_connection_read_write_dispatch(info->connection, 0);
} while (info->connection &&
dbus_connection_get_is_connected(info->connection) &&
dbus_connection_get_dispatch_status(info->connection) ==
DBUS_DISPATCH_DATA_REMAINS);
}
}
static void
block_handler(pointer data, struct timeval **tv, pointer read_mask)
{
}
/**
* Disconnect (if we haven't already been forcefully disconnected), clean up
* after ourselves, and call all registered disconnect hooks.
*/
static void
teardown(void)
{
struct config_dbus_core_hook *hook;
if (bus_info.timer) {
TimerFree(bus_info.timer);
bus_info.timer = NULL;
}
/* We should really have pre-disconnect hooks and run them here, for
* completeness. But then it gets awkward, given that you can't
* guarantee that they'll be called ... */
if (bus_info.connection)
dbus_connection_unref(bus_info.connection);
RemoveBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info);
if (bus_info.fd != -1)
RemoveGeneralSocket(bus_info.fd);
bus_info.fd = -1;
bus_info.connection = NULL;
for (hook = bus_info.hooks; hook; hook = hook->next) {
if (hook->disconnect)
hook->disconnect(hook->data);
}
}
/**
* This is a filter, which only handles the disconnected signal, which
* doesn't go to the normal message handling function. This takes
* precedence over the message handling function, so have have to be
* careful to ignore anything we don't want to deal with here.
*/
static DBusHandlerResult
message_filter(DBusConnection * connection, DBusMessage * message, void *data)
{
/* If we get disconnected, then take everything down, and attempt to
* reconnect immediately (assuming it's just a restart). The
* connection isn't valid at this point, so throw it out immediately. */
if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
DebugF("[config/dbus-core] disconnected from bus\n");
bus_info.connection = NULL;
teardown();
if (bus_info.timer)
TimerFree(bus_info.timer);
bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL);
return DBUS_HANDLER_RESULT_HANDLED;
}
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
/**
* Attempt to connect to the system bus, and set a filter to deal with
* disconnection (see message_filter above).
*
* @return 1 on success, 0 on failure.
*/
static int
connect_to_bus(void)
{
DBusError error;
struct config_dbus_core_hook *hook;
dbus_error_init(&error);
bus_info.connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
if (!bus_info.connection || dbus_error_is_set(&error)) {
DebugF("[config/dbus-core] error connecting to system bus: %s (%s)\n",
error.name, error.message);
goto err_begin;
}
/* Thankyou. Really, thankyou. */
dbus_connection_set_exit_on_disconnect(bus_info.connection, FALSE);
if (!dbus_connection_get_unix_fd(bus_info.connection, &bus_info.fd)) {
ErrorF("[config/dbus-core] couldn't get fd for system bus\n");
goto err_unref;
}
if (!dbus_connection_add_filter(bus_info.connection, message_filter,
&bus_info, NULL)) {
ErrorF("[config/dbus-core] couldn't add filter: %s (%s)\n", error.name,
error.message);
goto err_fd;
}
dbus_error_free(&error);
AddGeneralSocket(bus_info.fd);
RegisterBlockAndWakeupHandlers(block_handler, wakeup_handler, &bus_info);
for (hook = bus_info.hooks; hook; hook = hook->next) {
if (hook->connect)
hook->connect(bus_info.connection, hook->data);
}
return 1;
err_fd:
bus_info.fd = -1;
err_unref:
dbus_connection_unref(bus_info.connection);
bus_info.connection = NULL;
err_begin:
dbus_error_free(&error);
return 0;
}
static CARD32
reconnect_timer(OsTimerPtr timer, CARD32 time, pointer arg)
{
if (connect_to_bus()) {
TimerFree(bus_info.timer);
bus_info.timer = NULL;
return 0;
}
else {
return RECONNECT_DELAY;
}
}
int
config_dbus_core_add_hook(struct config_dbus_core_hook *hook)
{
struct config_dbus_core_hook **prev;
for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next);
hook->next = NULL;
*prev = hook;
/* If we're already connected, call the connect hook. */
if (bus_info.connection)
hook->connect(bus_info.connection, hook->data);
return 1;
}
void
config_dbus_core_remove_hook(struct config_dbus_core_hook *hook)
{
struct config_dbus_core_hook **prev;
for (prev = &bus_info.hooks; *prev; prev = &(*prev)->next) {
if (*prev == hook) {
*prev = hook->next;
break;
}
}
}
int
config_dbus_core_init(void)
{
memset(&bus_info, 0, sizeof(bus_info));
bus_info.fd = -1;
bus_info.hooks = NULL;
bus_info.connection = NULL;
bus_info.timer = TimerSet(NULL, 0, 1, reconnect_timer, NULL);
return 1;
}
void
config_dbus_core_fini(void)
{
teardown();
}