weston/src/dbus.c

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/*
* Copyright © 2013 David Herrmann <dh.herrmann@gmail.com>
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name of the copyright holders not be used in
* advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. The copyright holders make
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* DBus Helpers
* This file contains the dbus mainloop integration and several helpers to
* make lowlevel libdbus access easier.
*/
#include "config.h"
#include <dbus/dbus.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include <sys/timerfd.h>
#include <unistd.h>
#include <wayland-server.h>
#include "compositor.h"
#include "dbus.h"
/*
* DBus Mainloop Integration
* weston_dbus_bind() and weston_dbus_unbind() allow to bind an existing
* DBusConnection to an existing wl_event_loop object. All dbus dispatching
* is then nicely integrated into the wayland event loop.
* Note that this only provides basic watch and timeout dispatching. No
* remote thread wakeup, signal handling or other dbus insanity is supported.
* This is fine as long as you don't use any of the deprecated libdbus
* interfaces (like waking up remote threads..). There is really no rational
* reason to support these.
*/
static int weston_dbus_dispatch_watch(int fd, uint32_t mask, void *data)
{
DBusWatch *watch = data;
uint32_t flags = 0;
if (dbus_watch_get_enabled(watch)) {
if (mask & WL_EVENT_READABLE)
flags |= DBUS_WATCH_READABLE;
if (mask & WL_EVENT_WRITABLE)
flags |= DBUS_WATCH_WRITABLE;
if (mask & WL_EVENT_HANGUP)
flags |= DBUS_WATCH_HANGUP;
if (mask & WL_EVENT_ERROR)
flags |= DBUS_WATCH_ERROR;
dbus_watch_handle(watch, flags);
}
return 0;
}
static dbus_bool_t weston_dbus_add_watch(DBusWatch *watch, void *data)
{
struct wl_event_loop *loop = data;
struct wl_event_source *s;
int fd;
uint32_t mask = 0, flags;
if (dbus_watch_get_enabled(watch)) {
flags = dbus_watch_get_flags(watch);
if (flags & DBUS_WATCH_READABLE)
mask |= WL_EVENT_READABLE;
if (flags & DBUS_WATCH_WRITABLE)
mask |= WL_EVENT_WRITABLE;
}
fd = dbus_watch_get_unix_fd(watch);
s = wl_event_loop_add_fd(loop, fd, mask, weston_dbus_dispatch_watch,
watch);
if (!s)
return FALSE;
dbus_watch_set_data(watch, s, NULL);
return TRUE;
}
static void weston_dbus_remove_watch(DBusWatch *watch, void *data)
{
struct wl_event_source *s;
s = dbus_watch_get_data(watch);
if (!s)
return;
wl_event_source_remove(s);
}
static void weston_dbus_toggle_watch(DBusWatch *watch, void *data)
{
struct wl_event_source *s;
uint32_t mask = 0, flags;
s = dbus_watch_get_data(watch);
if (!s)
return;
if (dbus_watch_get_enabled(watch)) {
flags = dbus_watch_get_flags(watch);
if (flags & DBUS_WATCH_READABLE)
mask |= WL_EVENT_READABLE;
if (flags & DBUS_WATCH_WRITABLE)
mask |= WL_EVENT_WRITABLE;
}
wl_event_source_fd_update(s, mask);
}
static int weston_dbus_dispatch_timeout(void *data)
{
DBusTimeout *timeout = data;
if (dbus_timeout_get_enabled(timeout))
dbus_timeout_handle(timeout);
return 0;
}
static int weston_dbus_adjust_timeout(DBusTimeout *timeout,
struct wl_event_source *s)
{
int64_t t = 0;
if (dbus_timeout_get_enabled(timeout))
t = dbus_timeout_get_interval(timeout);
return wl_event_source_timer_update(s, t);
}
static dbus_bool_t weston_dbus_add_timeout(DBusTimeout *timeout, void *data)
{
struct wl_event_loop *loop = data;
struct wl_event_source *s;
int r;
s = wl_event_loop_add_timer(loop, weston_dbus_dispatch_timeout,
timeout);
if (!s)
return FALSE;
r = weston_dbus_adjust_timeout(timeout, s);
if (r < 0) {
wl_event_source_remove(s);
return FALSE;
}
dbus_timeout_set_data(timeout, s, NULL);
return TRUE;
}
static void weston_dbus_remove_timeout(DBusTimeout *timeout, void *data)
{
struct wl_event_source *s;
s = dbus_timeout_get_data(timeout);
if (!s)
return;
wl_event_source_remove(s);
}
static void weston_dbus_toggle_timeout(DBusTimeout *timeout, void *data)
{
struct wl_event_source *s;
s = dbus_timeout_get_data(timeout);
if (!s)
return;
weston_dbus_adjust_timeout(timeout, s);
}
static int weston_dbus_dispatch(int fd, uint32_t mask, void *data)
{
DBusConnection *c = data;
int r;
do {
r = dbus_connection_dispatch(c);
if (r == DBUS_DISPATCH_COMPLETE)
r = 0;
else if (r == DBUS_DISPATCH_DATA_REMAINS)
r = -EAGAIN;
else if (r == DBUS_DISPATCH_NEED_MEMORY)
r = -ENOMEM;
else
r = -EIO;
} while (r == -EAGAIN);
if (r)
weston_log("cannot dispatch dbus events: %d\n", r);
return 0;
}
static int weston_dbus_bind(struct wl_event_loop *loop, DBusConnection *c,
struct wl_event_source **ctx_out)
{
bool b;
int r, fd;
/* Idle events cannot reschedule themselves, therefore we use a dummy
* event-fd and mark it for post-dispatch. Hence, the dbus
* dispatcher is called after every dispatch-round.
* This is required as dbus doesn't allow dispatching events from
* within its own event sources. */
fd = eventfd(0, EFD_CLOEXEC);
if (fd < 0)
return -errno;
*ctx_out = wl_event_loop_add_fd(loop, fd, 0, weston_dbus_dispatch, c);
close(fd);
if (!*ctx_out)
return -ENOMEM;
wl_event_source_check(*ctx_out);
b = dbus_connection_set_watch_functions(c,
weston_dbus_add_watch,
weston_dbus_remove_watch,
weston_dbus_toggle_watch,
loop,
NULL);
if (!b) {
r = -ENOMEM;
goto error;
}
b = dbus_connection_set_timeout_functions(c,
weston_dbus_add_timeout,
weston_dbus_remove_timeout,
weston_dbus_toggle_timeout,
loop,
NULL);
if (!b) {
r = -ENOMEM;
goto error;
}
dbus_connection_ref(c);
return 0;
error:
dbus_connection_set_timeout_functions(c, NULL, NULL, NULL,
NULL, NULL);
dbus_connection_set_watch_functions(c, NULL, NULL, NULL,
NULL, NULL);
wl_event_source_remove(*ctx_out);
*ctx_out = NULL;
return r;
}
static void weston_dbus_unbind(DBusConnection *c, struct wl_event_source *ctx)
{
dbus_connection_set_timeout_functions(c, NULL, NULL, NULL,
NULL, NULL);
dbus_connection_set_watch_functions(c, NULL, NULL, NULL,
NULL, NULL);
dbus_connection_unref(c);
wl_event_source_remove(ctx);
}
/*
* Convenience Helpers
* Several convenience helpers are provided to make using dbus in weston
* easier. We don't use any of the gdbus or qdbus helpers as they pull in
* huge dependencies and actually are quite awful to use. Instead, we only
* use the basic low-level libdbus library.
*/
int weston_dbus_open(struct wl_event_loop *loop, DBusBusType bus,
DBusConnection **out, struct wl_event_source **ctx_out)
{
DBusConnection *c;
int r;
/* Ihhh, global state.. stupid dbus. */
dbus_connection_set_change_sigpipe(FALSE);
/* This is actually synchronous. It blocks for some authentication and
* setup. We just trust the dbus-server here and accept this blocking
* call. There is no real reason to complicate things further and make
* this asynchronous/non-blocking. A context should be created during
* thead/process/app setup, so blocking calls should be fine. */
c = dbus_bus_get_private(bus, NULL);
if (!c)
return -EIO;
dbus_connection_set_exit_on_disconnect(c, FALSE);
r = weston_dbus_bind(loop, c, ctx_out);
if (r < 0)
goto error;
*out = c;
return r;
error:
dbus_connection_close(c);
dbus_connection_unref(c);
return r;
}
void weston_dbus_close(DBusConnection *c, struct wl_event_source *ctx)
{
weston_dbus_unbind(c, ctx);
dbus_connection_close(c);
dbus_connection_unref(c);
}