Re: [Qemu-devel] [for-2.9 2/8] char: Fix socket with "type": "vsock" address

[Markus Armbruster <armbru@redhat.com>]

Marc-André Lureau <marcandre.lureau@redhat.com> writes:

> ----- Original Message -----
>> 
>> Hi
>> 
>> ----- Original Message -----
>> > Watch this:
>> > 
>> >     $ qemu-system-x86_64 -nodefaults -S -display none -qmp stdio
>> >     {"QMP": {"version": {"qemu": {"micro": 91, "minor": 8, "major": 2},
>> >     "package": " (v2.8.0-1195-gf84141e-dirty)"}, "capabilities": []}}
>> >     { "execute": "qmp_capabilities" }
>> >     {"return": {}}
>> >     { "execute": "chardev-add", "arguments": { "id": "chr0", "backend": {
>> >     "type": "socket", "data": { "addr": { "type": "vsock", "data": { "cid":
>> >     "CID", "port": "P" }}}}}}
>> >     Aborted (core dumped)
>> > 
>> > Crashes because SocketAddress_to_str() is blissfully unaware of
>> > SOCKET_ADDRESS_KIND_VSOCK.  Fix that.  Pick the output format to match
>> > socket_parse(), just like the existing formats.
>> > 
>> > Cc: Stefan Hajnoczi <stefanha@redhat.com>
>> > Cc: Paolo Bonzini <pbonzini@redhat.com>
>> > Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
>> > Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> 
>> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Thanks!

>> > ---
>> >  chardev/char-socket.c | 4 ++++
>> >  1 file changed, 4 insertions(+)
>> > 
>> > diff --git a/chardev/char-socket.c b/chardev/char-socket.c
>> > index 6344b07..36ab0d6 100644
>> > --- a/chardev/char-socket.c
>> > +++ b/chardev/char-socket.c
>> > @@ -357,6 +357,10 @@ static char *SocketAddress_to_str(const char *prefix,
>> > SocketAddress *addr,
>> >          return g_strdup_printf("%sfd:%s%s", prefix, addr->u.fd.data->str,
>> >                                 is_listen ? ",server" : "");
>> >          break;
>> > +    case SOCKET_ADDRESS_KIND_VSOCK:
>> > +        return g_strdup_printf("%svsock:%s:%s", prefix,
>> > +                               addr->u.vsock.data->cid,
>> > +                               addr->u.vsock.data->port);
>> >      default:
>> >          abort();
>> 
>> ooch.. may I suggest we don't abort() here? g_return_val_if_fail() perhaps a
>> more judicious choice?
>
> -> g_return_if_reached()

If we reach the default label, program state is messed up, and
continuing is unsafe.

In case we decide we want to push our luck and continue anyway: as far
as I can tell, we don't use g_log() anywhere.  We can discuss whether we
have uses for it, but hard freeze is a bad time to actually introduce
it.