Re: [Qemu-devel] Writing a C library to generate qemu command lines and configuration files

[Markus Armbruster <armbru@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 02/05/2017 16:59, Richard W.M. Jones wrote:
>>> To answer your question: you have to double comma after '=', or else it
>>> terminates the value.  There is no other quoting.
>>
>> Hmm, is that really right?

I should avoid absolutes when it comes to QemuOpts...

>>                             It seems to me that any comma must be
>> doubled.  For example:
>> 
>> $ qemu-system-x86_64 -name foo,bar -writeconfig - -hda die
>> qemu-system-x86_64: -name foo,bar: Invalid parameter 'bar'
>
> That's because, as you found out, "-name" is not a simple option but a
> compound one; "-name foo" is short for "-name guest=foo" (compare
> "-device e1000").
>
> The grammar mentioned in util/keyval.c says that you have to double
> comma in a value, *and* comma is completely invalid in a key.
>
> If you have '=', you have to double commas after it and cannot use it
> before.
>
> If you have no '=' at all, then you have to double comma too.

Yes.  My description wasn't precise enough, sorry.

Please take note that the grammar in util/keyval.c does *not* produce
the exact QemuOpts language.  It's close, but it doesn't reproduce all
corner cases.  Anything it does produce should have the same meaning in
QemuOpts.

> Paolo
>
>> $ qemu-system-x86_64 -name foo,,bar -writeconfig - -hda die
>> # qemu config file
>> 
>> [name]
>>   guest = "foo,bar"