selinux: rework selinux access check logic

a) Instead of parsing the bus messages inside of selinux-access.c
simply pass everything pre-parsed in the functions

b) implement the access checking with a macro that resolves to nothing
on non-selinux builds

c) split out the selinux checks into their own sources
selinux-util.[ch]

d) this unifies the job creation code behind the D-Bus calls
Manager.StartUnit() and Unit.Start().

1 files changed, 5 insertions, 2 deletions

diff --git a/src/shared/dbus-common.h b/src/shared/dbus-common.h
index 7294206bc4..394ab4cb60 100644
--- a/src/shared/dbus-common.h
+++ b/src/shared/dbus-common.h
@@ -214,5 +214,8 @@ int bus_method_call_with_reply(DBusConnection *bus,
                                DBusError *return_error,
                                int first_arg_type, ...);
 
-void dbus_message_unref_p(DBusMessage **reply);
-#define _cleanup_dbus_msg_unref_ __attribute__((cleanup(dbus_message_unref_p)))
+const char *bus_message_get_sender_with_fallback(DBusMessage *m);
+
+void bus_message_unrefp(DBusMessage **reply);
+
+#define _cleanup_dbus_message_unref_ __attribute__((cleanup(bus_message_unrefp)))