On Thu, Mar 23, 2023 at 01:10:15PM +0100, Laszlo Ersek wrote:
> From: "Richard W.M. Jones" <rjo...@redhat.com>
>
> To allow us to name the socket passed down to the NBD server when
> calling nbd_connect_systemd_socket_activation(3), we need to add the
> field to the handle and add access functions.
>
> [Laszlo's note: originally posted by Rich at
> <https://listman.redhat.com/archives/libguestfs/2023-January/030557.html>.
> I've renamed "sa_name" to "sact_name", due to <signal.h> reserving symbols
> with the "sa_" prefix. This corresponds to earlier patches in this series,
> such as 'socket activation: rename sa_(tmpdir|sockpath) to
> sact_(tmpdir|sockpath)' and 'ocaml: rename "sa_u" to "saddr_u"'.]
>
> Message-Id: <20230130225521.1771496-4-rjo...@redhat.com>
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
> Reviewed-by: Richard W.M. Jones <rjo...@redhat.com>
> ---
>
> +++ b/generator/API.ml
> @@ -2036,15 +2036,62 @@ "connect_systemd_socket_activation", {
>
> When the NBD handle is closed the server subprocess
> is killed.
> +
> +=head3 Socket name
> +
> +The socket activation protocol lets you optionally give
> +the socket a name. If used, the name is passed to the
> +NBD server using the C<LISTEN_FDNAMES> environment
> +variable. To provide a socket name, call
> +L<nbd_set_socket_activation_name(3)> before calling
> +the connect function.
> " ^ blocking_connect_call_description;
> see_also = [Link "aio_connect_systemd_socket_activation";
> Link "connect_command"; Link "kill_subprocess";
> Link "set_opt_mode";
> + Link "set_socket_activation_name";
> + Link "get_socket_activation_name";
> ExternalLink ("qemu-nbd", 1);
> URLLink
> "http://0pointer.de/blog/projects/socket-activation.html";];
> example = Some "examples/open-qcow2.c";
> };
>
> + "set_socket_activation_name", {
> + default_call with
> + args = [ String "socket_name" ]; ret = RErr;
> + shortdesc = "set the socket activation name";
I recommend adding permitted_states = [ Created ]; on this one - it
makes no sense to change the socket name after connection.
> + longdesc = "\
> +When running an NBD server using
> +L<nbd_connect_systemd_socket_activation(3)> you can optionally
> +name the socket. Call this function before connecting to the
> +server.
> +
> +Some servers such as L<qemu-storage-daemon(1)>
> +can use this information to associate the socket with a name
> +used on the command line, but most servers will ignore it.
> +The name is passed through the C<LISTEN_FDNAMES> environment
> +variable.
qemu-storage-daemon doesn't do it yet, but there's a strong likelihood
of it moving that direction, so I don't mind leaving this statement
as-is describing what we hope is the future state of things.
> +
> +The parameter C<socket_name> can be a short alphanumeric string.
> +If it is set to the empty string (also the default when the handle
> +is created) then no name is passed to the server.";
> + see_also = [Link "connect_systemd_socket_activation";
> + Link "get_socket_activation_name"];
> + };
> +
> + "get_socket_activation_name", {
> + default_call with
> + args = []; ret = RString;
> + shortdesc = "get the socket activation name";
Unlike set_ which only makes sense in Created, get_ makes sense over
the entire life of the handle, so no permitted_state entry needed
here.
My suggested one-line addition is easy enough to add that I'm fine if
you do that without needing a v5.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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