Re: [PATCH 02/10] qemu-options: update to show preferred boolean syntax for -chardev

[Daniel P . Berrangé]

On Tue, Feb 16, 2021 at 09:08:39PM +0000, Peter Maydell wrote:
> On Tue, 16 Feb 2021 at 19:10, Daniel P. Berrangé <berrange@redhat.com> wrote:
> >
> > The preferred syntax is to use "foo=on|off", rather than a bare
> > "foo" or "nofoo".
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > -    "-chardev 
> > socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
> > -    "         
> > [,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
> > +    "-chardev 
> > socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,delay=on|off][,reconnect=seconds]\n"
> 
> Watch out, 'nodelay' is a special case, where the option name itself
> starts with 'no':
> 
> { 'struct': 'ChardevSocket',
>   'data': { 'addr': 'SocketAddressLegacy',
>             '*tls-creds': 'str',
>             '*tls-authz'  : 'str',
>             '*server': 'bool',
>             '*wait': 'bool',
>             '*nodelay': 'bool',
>             '*telnet': 'bool',
>             '*tn3270': 'bool',
>             '*websocket': 'bool',
>             '*reconnect': 'int' },
>   'base': 'ChardevCommon' }
> 
> (because it's setting the TCP_NODELAY option).
> 
> This probably applies elsewhere, eg I suspect the 'nodelay' in
> patch 1 also should remain.

For added fun that's not what we call it in QemuOpts though !

In qemu_chr_parse_socket we do:

    sock->has_nodelay = qemu_opt_get(opts, "delay");
    sock->nodelay = !qemu_opt_get_bool(opts, "delay", true);

So we really were relying on the "no$FOO" syntax here

Arguably it would be saner if we really did call it "nodelay" at the
QemuOpts level. I guess we trying to avoid having "nonodelay".

Regards,
Daniel
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