sbus: add a{sas} get invoker Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

SBUS: Return / if an object path getter returns NULL Reviewed-by: Stef Walter <stefw@redhat.com> Reviewed-by: Pavel Březina <pbrezina@redhat.com>

SBUS: Return empty string if a string getter returns NULL In line with getters never returning errors, a getter should return an empty string instead of NULL in case a string-like property in SSSD is not set. Reviewed-by: Stef Walter <stefw@redhat.com> Reviewed-by: Pavel Březina <pbrezina@redhat.com>

SBUS: Implement org.freedesktop.DBus.Properties.Get for primitive types This patch implements type-safe getters for primitive types and their arrays. The patch includes unit tests of all supported types and arrays of these types. All getter are synchronous. The getters never fail, instead, they return a default or 'not defined' value. Making the getters synchronous and always returning a value will make it significantly easier to implement the GetAll method. Reviewed-by: Stef Walter <stefw@redhat.com> Reviewed-by: Pavel Březina <pbrezina@redhat.com>

sbus_codegen_tests: Add test case type-safe handler args This adds a big test case for invoking a handler with all supported basic arguments, and constructing a reply with the same. Lots of tedious code, but worth it to make sure things work well.

sbus: Add type-safe DBus method handlers and finish functions Type safe method handlers allow methods not to have to do tedious unwrapping and wrapping of DBus method call messages or replies. Arguments of the following DBus types are supported in type-safe method handlers. In addition arrays of these are supported. y: uint8_t b: bool (but no arrays, yet) n: int16_t q: uint16_t i: int32_t u: uint32_t x: int64_t t: uint64_t d: double s: char * (utf8 string) o: char * (object path) As an exception, arrays of booleans are not supported, but could be added later. Other more complex types could be added later if desired. If a method has other argument types, then it must be marked as having a raw handler (see below). Internally each method can have a type specific invoker function which unpacks the incoming arguments and invokes the method handler with the correct arguments. Each method also has a finish which accepts the type-safe out arguments (ie: return values) and builds the reply message. Like other request 'finish' functions, these free the request talloc context, and are to be used in place of sbus_request_finish() or friends. Raw method handlers parse their own method arguments, and prepare their own reply (ideally using sbus_request_finish() helpers). They can also do strange things like have variable arguments. To mark a DBus method as having a raw method handler use the following annotation: <annotation name="org.freedesktop.sssd.RawHandler" value="true"/> Raw methods do not have invokers or finish functions. I've left all of the internal peer to peer communication using raw method handlers. No code changes here.

sbus: Add sbus_vtable and update codegen to support it Each interface is a vtable structure derived from sbus_vtable, in the sense that it has an sbus_vtable struct as its first argument. This lets us upcast the interface vtable structure to an sbus_vtable and dispatch to it dynamically and cleanly. The interface metadata contains information about which vtable offset in the interface metadata should be dispatched to for a given function. This is a common scheme, not only among dbus implementations, but also compiled languages. Currently all the vtable functions are of type sbus_msg_handler_fn. These are the handlers we are familiar with and perform raw processing of the message. Later commits will introduce type safe handlers that levelage compile checking and automatic argument packing/unpacking. Although this may seem contrived now, the remainder of the dbus infrastructure work will build on this, including ofd.Properties, ofd.ObjectManager, ofd.Introspect, compiler checked type safe unpacking/packing, etc. The codegen now generates vtable structures for each interface along-side the metadata, and fills in vtable offsets appropriately. It is obviously still possible to hand-craft such vtables and metadata if needed for a special case. Once again examples output can be found at: src/tests/sbus_codegen_tests_generated.h Reviewed-by: Jakub Hrozek <jhrozek@redhat.com> Reviewed-by: Sumit Bose <sbose@redhat.com> Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com> Reviewed-by: Simo Sorce <simo@redhat.com>

sbus: Add meta data structures and code generator These metadata structures hold the information about all the details of a DBus interface. They are typically generated from the canonical XML form of the DBus interface, although they may also be hand crafted. Add some handy functions for looking up methods, props, signals, in the metadata of an interface. Currently lookups are just done by looking through an array. If performance becomes an issue (ie: very large interfaces) it would be really easy to sort things and use bsearch(). Later commits will include some definitions using this metadata and related functions. DBus interfaces are defined here: http://dbus.freedesktop.org/doc/dbus-specification.html#introspection-format The introspection data format has become the standard way to represent a DBus interface. For many examples see /usr/share/dbus-1/interfaces/ on a typical linux machine. A word about annotations. These are extra flags or values that can be assigned to anything. So far, the codegen supports this annotation: org.freedesktop.DBus.GLib.CSymbol - An annotation specified in the specification that tells us what C symbol to generate for a given interface or method. By default the codegen will build up a symbol name from the DBus name. It is possible to confuse the code generator into producing invalid C code (with strange method names, for example), but the C compiler catches such silliness right away. Add tests testing basic features of the codegen and poking through the metadata it creates. Also test the metadata lookup functions. Generated code is checked in for easy discovery. An example of the XML interface definitions can be found at: src/tests/sbus_codegen_tests.xml And an example of the generated header can be found here: src/tests/sbus_codegen_tests_generated.h Reviewed-by: Jakub Hrozek <jhrozek@redhat.com> Reviewed-by: Sumit Bose <sbose@redhat.com> Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com> Reviewed-by: Simo Sorce <simo@redhat.com>