Introduce a new API to get libvirt version. It is worth noting, that
libvirt-admin and libvirt share the same version number. Unfortunately,
our existing API isn't generic enough to be used with virAdmConnectPtr
as well. Also this patch wires up this API to the virt-admin client
as a generic cmdVersion command.
As we need a client disconnect handler, we also need a mechanism to register
such handlers for a client. This patch introduced both the close callbacks and
also the client vshAdmCatchDisconnect handler to be registered with it. By
registering the handler we still need to make sure the client can react to
daemon's events like disconnect or keepalive, so asynchronous I/O event polling
is necessary to be enabled too.
Since most of our APIs rely on an acive functional connection to a daemon and
we have such a mechanism in libvirt already, there's need to have such a way in
libvirt-admin as well. By introducing a new public API, this patch provides
support to check for an active connection.
Unfortunately, client side version retrieval API virGetVersion uses
one-time initialization (due to the fact we might not have initialized the
library by calling connect prior to this) which is not completely compatible
with admin initialization. This API is rather simplistic and reimplementing
it for admin might be the preferred method of reusing it. Note that even though
the method will be reimplemented, the version number is still the same for both
the libvirt and libvirt-admin library.
Since we're linking this into libvirtd we need some symbols to be public
but not part of the public API so mark them as
LIBVIRT_ADMIN_PRIVATE_<VERSION> as we do with libvirt.
Making all other symbols local makes sure we don't accidentally leak
unwanted ones.
