[syslinux] ALLOWOPTIONS directive

[Ady]

> 
> My summary:
>    reviewing ALLOWOPTIONS found  reasons
>    for further reviewing 'ALLOWOPTIONS'
> 
> Op 2014-07-12 om 04:35 schreef Ady:
> > 
> > > I have some questions about "ALLOWOPTIONS 0".
> > > 
> > > [quote]
> > > ALLOWOPTIONS flag_val 
> > > If flag_val is 0, the user is not allowed to specify any arguments on 
> > > the kernel command line. The only options recognized are those 
> > > specified in an APPEND) statement. The default is 1.
> > > [/quote]
> > > 
> > > My understanding of the behavior of "ALLOWOPTIONS 0" is that unless I 
> > > type-in a command that is exactly the same as the result of executing 
> > > a label, then the command is "not accepted" ("not allowed").
> > > 
> > >  1_ Is my understanding correct?
> 
> Yes, at least that is how I understand the provided [quote/]
> 
> 
> > >  2_ Are there any cases in which the resulting behavior is different 
> > > from using the IMPLICIT directive (with respective labels)?
> > > 
> > > While using 'ALLOWOPTIONS 0'...
> > >   3_ Should typing-in a 'label' (instead of the whole equivalent 
> > > command) be accepted too?
> 
> Yes, chosing a 'label' should be possible.
> Changing the behaviour of the label not.
> 
> 
> > >   4_ If I type-in a 'label' in the CLI, should additional options be 
> > > allowed?
> 
> See 3_
> 
> > >   5_ If I press Tab in [vesa]menu.c32 and delete part of the command, 
> > > is the resulting command allowed?
> 
> I think the question is 'should it be allowed?'
> 
> 
> > >   6_ How exactly is a command "not accepted"? What happens then? Is 
> > > the entire command rejected? Or is the typed-in kernel executed 
> > > without options? Or is the DEFAULT command executed (without 
> > > options)? Or is the ONERROR command executed (without options)? Or is 
> > > the first label found with "similar" options executed? Or...?
> 
> I don't know.
> 
> 
> > > The reason I am asking these questions is because I am testing 
> > > "ALLOWOPTIONS 0" and I am slightly confused by the result. Knowing 
> > > what I am supposed to expect would help me test the directive 
> > > accordingly.
> 
> I think Ady found some good reasons to review 'ALLOWOPTIONS' further.
> 
> 
> > > TIA,
> > > Ady.
> > 
> > Anyone? Please?
> 
> Sorry for not sending an acknowledge message like this more earlier.
> 
> 
> Groeten
> Geert Stappers
> -- 
> Leven en laten leven
> 

Thank you for your reply.

With regards to my Q#6, I am still looking for more-specific answers.

The current behavior of this directive is confusing to me. I don't 
know whether I am misunderstanding something, or whether the current 
behavior is not exactly a perfect match to what should be expected 
(aka. a bug). Without understanding the latter, I cannot get to 
useful conclusions.

I hope someone can answer to these questions.

TIA,
Ady.