Pretty much everywhere else we use the generic term "machine" when
referring to containers in API, so let's do though in sd-bus too. In
particular, since the concept of a "container" exists in sd-bus too, but
as part of the marshalling system.
The bus_map_all_properties() helper calls
org.freedesktop.DBus.Properties.GetAll() on a given target and parses the
result according to a given property-table. This simplifies dealing with
DBus.Properties significantly. However, the function is blocking and thus
not really useful in many situations.
This patch extracts the core of this function and adds two new helpers
which directly take dbus-messages as arguments. This way, you can issue
asynchronous requests and parse the result via these helpers:
bus_message_map_all_properties():
This is the same as bus_map_all_properties() but takes the result
message from a GetAll() request as argument. You can thus issue an
asynchronous GetAll() request and then use this helper once you got
the result.
bus_message_map_properties_changed():
This function takes a signal-message that was retrieved via a
PropertiesChanged signal and then parses it like if you retrieved
it via GetAll(). Furthermore, this function returns the number of
matched properties that got invalidated by the PropertiesChanged
signal, but didn't carry the new value. This way, the caller can
issue a new GetAll() request and then parse the result.
The old function bus_map_all_properties() is functionally unchanged, but
now uses bus_message_map_all_properties() internally.
First, let's drop the "bus" argument, we can determine it from the
message anyway.
Secondly, determine the right callback/userdata pair automatically from
what is currently is being dispatched. This should simplify things a lot
for us, since it makes it unnecessary to pass pointers through the
original handlers through all functions when we process messages, which
might require authentication.
This is a generalization of the vtable privilege check we already have,
but exported, and hence useful when preparing for a polkit change.
This will deal with the complexity that on dbus1 one cannot trust the
capability field we retrieve via the bus, since it is read via
/proc/$$/stat (and thus might be out-of-date) rather than directly from
the message (like on kdbus) or bus connection (as for uid creds on
dbus1).
Also, port over all code to this new API.
Since b5eca3a205 we don't attempt to GC
busses anymore when unsent messages remain that keep their reference,
when they otherwise are not referenced anymore. This means that if we
explicitly want connections to go away, we need to close them.
With this change we will no do so explicitly wherver we connect to the
bus from a main program (and thus know when the bus connection should go
away), or when we create a private bus connection, that really should go
away after our use.
This fixes connection leaks in the NSS and PAM modules.
This makes callback behaviour more like sd-event or sd-resolve, and
creates proper object for unregistering callbacks.
Taking the refernce to the slot is optional. If not taken life time of
the slot will be bound to the underlying bus object (or in the case of
an async call until the reply has been recieved).
The code for parsing these properties is shared with "systemctl
set-property", which means all the resource control settings are
immediately available.
