This interface is responsible for handling properties of all objects in
a given path. Right now it only registers itself, doing nothing useful.
A conversion to this new layout will be done by subsequent patches.
org.freedesktop.org.DBus.Properties spec can be found at
http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-properties
When we add a signal handler with g_dbus_add_signal_watch(), this
function tries to multiplex the matches added in libdbus by checking
if there's a previous filter_data with the same fields. However, if the
field is NULL it accepts as being the same. The result is that the
following watches will use the same filter data:
watch1 = g_dbus_add_signal_watch(conn, BUS_NAME, NULL, iface, member,
cb1, data1, NULL);
watch2 = g_dbus_add_signal_watch(conn, BUS_NAME, "/path2", iface, member,
cb2, data2, NULL);
watch3 = g_dbus_add_signal_watch(conn, BUS_NAME, "/path3", iface, member,
cb3, data3, NULL);
The result is that when a signal arrives with path == "/path2", all 3
callbacks above will be called, with the same signal delivered to all of
them.
Another problem is that, if we invert the calls like below, only signals
to cb1 will never be trigerred, nonetheless it used path == NULL.
watch2 = g_dbus_add_signal_watch(conn, BUS_NAME, "/path2", iface, member,
cb2, data2, NULL);
watch1 = g_dbus_add_signal_watch(conn, BUS_NAME, NULL, iface, member,
cb1, data1, NULL);
watch3 = g_dbus_add_signal_watch(conn, BUS_NAME, "/path3", iface, member,
cb3, data3, NULL);
This is fixed by not multiplexing the matchs with filter data if any of
the fields are different, including being NULL. When a signal arrives,
if a field is NULL we accept it as a match, but not when adding the
signal handler.
When getting disconnected from the bus sometimes (maybe always?)
dbus_watch_handle() can cause the "info" context to be free'd meaning
that we should not try to access it after the call. The only member we
need access to is the connection pointer and as the code already has a
ref() call for it it's only natural to solve the issue by adding a local
variable not dependent on "info".
The backtrace of the crash fixed looks as follows:
Invalid read of size 8
at 0x121085: watch_func (mainloop.c:105)
by 0x4C72694: g_main_context_dispatch (gmain.c:2539)
by 0x4C729C7: g_main_context_iterate.isra.23 (gmain.c:3146)
by 0x4C72DC1: g_main_loop_run (gmain.c:3340)
by 0x120541: main (main.c:551)
Address 0x5bbcd90 is 16 bytes inside a block of size 24 free'd
at 0x4A079AE: free (vg_replace_malloc.c:427)
by 0x4C7837E: g_free (gmem.c:252)
by 0x4F708BF: dbus_watch_set_data (dbus-watch.c:614)
by 0x4F70938: _dbus_watch_unref (dbus-watch.c:132)
by 0x4F6E9A7: _dbus_transport_handle_watch (dbus-transport.c:884)
by 0x4F59AFB: _dbus_connection_handle_watch (dbus-connection.c:1497)
by 0x4F70AF9: dbus_watch_handle (dbus-watch.c:683)
by 0x121084: watch_func (mainloop.c:103)
by 0x4C72694: g_main_context_dispatch (gmain.c:2539)
by 0x4C729C7: g_main_context_iterate.isra.23 (gmain.c:3146)
by 0x4C72DC1: g_main_loop_run (gmain.c:3340)
by 0x120541: main (main.c:551)
If there's a signal watch that's also watching for name
(data->name_watch) currently we are trying to remove the message_filter
twice since we may have the following call chain:
filter_data_remove_callback()
filter_data_free()
g_dbus_remove_watch()
filter_data_remove_callback()
filter_data_free()
dbus_connection_remove_filter()
dbus_connection_remove_filter()
Because of this we can't currently watch for signals passing the bus
name. After this patch we don't have this issue anymore.
We fix it by removing the filter before calling filter_data_free() if we
are the last filter_data and thus avoid calling
dbus_connection_remove_filter() twice.
Even though service watches accepted a "destroy" callback, they were
being ignored. This fix properly pass them along so they are called when
the watch is removed.
Address an issue in which the daemon incorrectly handles D-Bus main
loop timeouts by only removing timeouts that are not enabled when
D-Bus requests a timeout removal.
generate_introspection_xml generates the root <node> tags with a
'name' attribute. This seems to be a valid attribute but it is not
consistent with the way the D-Bus daemon generates empty nodes.
For example if we register "/foo/bar", D-Bus daemon will generate for
"/foo" a introspection which looks like this:
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
<node name="bar"/>
</node>
and generate_introspection_xml generates for "/foo/bar":
<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node name="/foo/bar">
</node>
Just don't add the 'name' attribute to the root node. The GLib
binding for D-Bus does it the same way.
Assume there is only one object registerd at "/". If we add a new
object at "/foo/bar" the introspection of "/" has to be updated. A new
node has to be added at "/".
invalidate_parent_data stops invaldating the whole path because the
boolean return value of dbus_connection_get_object_path_data is used
wrong.
If we get a TRUE just go on down in the path, if FALSE is return
dbus_connection_get_object_path_data has run out of memory.
This patch was generated by the following semantic patch
(http://coccinelle.lip6.fr/)
// <smpl>
@fix disable is_null,isnt_null1@
expression *E;
@@
- !E
+ E == NULL
// </smpl>
We where not dispatching data when a bus disconnects which cause
Disconnected signal to not be processed and thus causing the process to
either not exit or to not trigger callbacks registered with
g_dbus_set_disconnect_function.
To fix this now we always schedule a dispatch which will make sure data
still not processed will make its way to the proper handlers even if
disconnected.
Pending call should be removed if the watch is removed since the
application no longer expect that to be reached and may already freed the
data associated with it.
The bus name should be resolved when adding a watch by service name since
messages do always come with sender set to owner's bus name, also it
should listen to owner updates since it can change without invalidating
the watch.
In the case that parent path data needs to be invalidated we shouldn't
stop at the immediate parent if it doesn't have our own handler
registered but should continue upwards in the tree until we reach root
or our own handler.
This was triggering an assert inside libdbus when the timeout inside
the leaking pending call expired. The assert said that we were trying
to remove an nonexistent timeout.
filter_data_find return the first data registered in this case so there is
no guarantee that it return the same data as passed to
filter_data_remove_callback which is the one that should be removed.
The fix is to simple cache the connection removing the correct data before
checking if there is any filter left.
Timeouts should also be removed in the remove_timeout callback in
addition to the timeout_handler_free function. This is how dbus-glib
does it and it seems to prevent crashes in certain situations.
Current implementation of libdbus Request name is blocking, consequently
the first incomming message that triggered the service autostart is not
being processed properly.
Previously it was a specific case, now introspection is just another
interface, which is always implemented. It is registered/unregistered
when an object path is referenced first/last.
Lucas De Marchi
Luiz Augusto von Dentz
Johan Hedberg
Jaganath Kanakkassery
Mikel Astiz
Marcel Holtmann
Anderson Lizardo
Syam Sidhardhan
Szymon Janc
Grant Erickson
Daniel Wagner
Johan Hedberg
Luiz Augusto von Dentz
Zhenhua Zhang
Vinicius Costa Gomes
Forrest Zhao
Daniel Orstadius
Claudio Takahasi
RISKÓ Gergely
Denis Kenzior
Luiz Augusto von Dentz
Marcel Holtmann