Even if the lower-leveld dbus1 protocol calls it "serial", let's expose
the word "cookie" for this instead, as this is what kdbus uses and since
it doesn't imply monotonicity the same way "serial" does.
Previously we invalidated the peeked signature as soon as the caller
would recurse into a container, making stack based handling difficult.
With this change we will keep the peeked signature around until the user
advances to the next field.
Instead of calling it for each buffer append, increase allocation
exponentially and set the real value only at the end, when sealing off
the memfd.
This should drastically reduce the number of times we invoke the
ioctl().
We support unreffing NULL pointers just fine and we shouldn't pay the
_unlikely_() price for it, not get a debug message if we do, hence let's
not use assert_return() here.
This reverts commit f7e2bd5a80.
Most of these checks are not programming errors, but happen during
normal runtime. For example bus_kernel_pop_memfd() is called all the
time on non-kdbus systems and is supposed to quickly fail if kdbus is
not available. However, assert_return() makes this failure
expensive, and hence has no place here. With the most recent change to
assert_return() it will even log a debug message, which should never
happen here.
The name list and query functions now work differently in kdbus, as the
result is stored in the connection's pool, rather than being copied back
through the ioctl buffer. That also safes us some logic, as we don't
have to resize the communication buffer in a loop with growing buffer
sizes.
Due to this, KDBUS_CMD_MSG_RELEASE was renamed to KDBUS_CMD_FREE, as it
is now used outside the message logic as well.
This way we can unify handling of credentials that are attached to
messages, or can be queried for bus name owners or connection peers.
This also adds the ability to extend incomplete credential information
with data from /proc,
Also, provide a convenience call that will automatically determine the
most appropriate credential object for an incoming message, by using the
the attached information if possible, the sending name information if
available and otherwise the peer's credentials.
All calls that set a sd_bus_error structure will now return the same
error converted to a negative errno. This may be used as syntactic sugar
to return from a function and setting a bus_error structure in one go.
Also, translate all Linux Exyz (EIO, EINVAL, EUCLEAN, EPIPE, ...)
automatically into counterparts in the (new) "Posix.Error." namespace.
If we fail to allocate memory for the components of a sd_bus_error
automatically reset it to an OOM error which we always can write.
Message handler callbacks can be simplified drastically if the
dispatcher automatically replies to method calls if errors are returned.
Thus: add an sd_bus_error argument to all message handlers. When we
dispatch a message handler and it returns negative or a set sd_bus_error
we send this as message error back to the client. This means errors
returned by handlers by default are given back to clients instead of
rippling all the way up to the event loop, which is desirable to make
things robust.
As a side-effect we can now easily turn the SELinux checks into normal
function calls, since the method call dispatcher will generate the right
error replies automatically now.
Also, make sure we always pass the error structure to all property and
method handlers as last argument to follow the usual style of passing
variables for return values as last argument.
This patch converts PID 1 to libsystemd-bus and thus drops the
dependency on libdbus. The only remaining code using libdbus is a test
case that validates our bus marshalling against libdbus' marshalling,
and this dependency can be turned off.
This patch also adds a couple of things to libsystem-bus, that are
necessary to make the port work:
- Synthesizing of "Disconnected" messages when bus connections are
severed.
- Support for attaching multiple vtables for the same interface on the
same path.
This patch also fixes the SetDefaultTarget() and GetDefaultTarget() bus
calls which used an inappropriate signature.
As a side effect we will now generate PropertiesChanged messages which
carry property contents, rather than just invalidation information.
So far we used ENXIO whenever the user tried to read something from a
function that didn't carry the right type, and hence use the same error
here to indicate that what the user expected and what was in the message
didn't match up.
