bus-proxy: check passed parameter signature of all driver method calls
update TODO
bus-proxy: beef up policy enforcement

- actually return permission errors to clients

- use the right ucreds field

- fix error paths when we cannot keep track of locally acquired names
  due to OOM

- avoid unnecessary global variables

- log when the policy denies access

- enforce correct policy rule order

- always request all the metadata its we need to make decisions
sd-bus: be stricter with mismatches between dbus1 and kdbus message headers
sd-bus: optimize how we generate the well-known-names lists in messages from kdbus
sd-bus: fake valid well-known-names metadata for faked bus messages
sd-bus: unify logic how we patch the message source of driver messages
sd-bus: deal with whitespace in matches
sd-bus: when we get the list of well-known names back from kdbus we shouldn't confuse the empty list with unknown information
sd-bus: set creds info for "org.freedesktop.DBus.Local" generated messages, too
log: add an "error" parameter to all low-level logging calls and intrdouce log_error_errno() as log calls that take error numbers

This change has two benefits:

- The format string %m will now resolve to the specified error (or to
  errno if the specified error is 0. This allows getting rid of a ton of
  strerror() invocations, a function that is not thread-safe.

- The specified error can be passed to the journal in the ERRNO= field.

Now of course, we just need somebody to convert all cases of this:

        log_error("Something happened: %s", strerror(-r));

into thus:

        log_error_errno(-r, "Something happened: %m");
log: be a bit less wasteful when allocating buffers
log: rearrange log function naming

- Rename log_meta() → log_internal(), to follow naming scheme of most
  other log functions that are usually invoked through macros, but never
  directly.

- Rename log_info_object() to log_object_info(), simply because the
  object should be before any other parameters, to follow OO-style
  programming style.
selinux: log selinux log messages with LOG_AUTH facility
kdbus: set kernel attach mask before creating the first bus
kmod-setup: simplify kernel command line parsing