Re: [PATCH v2] conf: Stop parsing options at first non-option argument

[Stefano Brivio <sbrivio@redhat.com>]

On Thu, 8 Aug 2024 10:57:24 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Wed, Aug 07, 2024 at 01:28:40PM +0200, Stefano Brivio wrote:
> > Given that pasta supports specifying a command to be executed on the
> > command line, even without the usual -- separator as long as there's
> > no ambiguity, we shouldn't eat up options that are not meant for us.
> > 
> > Paul reports, for instance, that with:
> > 
> >   pasta --config-net ip -6 route
> > 
> > -6 is taken by pasta to mean --ipv6-only, and we execute 'ip route'.
> > That's because getopt_long(), by default, shuffles the argument list
> > to shift non-option arguments at the end.
> > 
> > Avoid that by adding '-' at the beginning of 'optstring', and mark the
> > position of the first non-option argument (getopt_long() will now
> > return the character code 1 once we hit it), so that we can use that
> > as command to run, or as PID for the target namespace.
> > 
> > Reported-by: Paul Holzinger <pholzing@redhat.com>
> > Signed-off-by: Stefano Brivio <sbrivio@redhat.com>  
> 
> Eh... I'm kind of ambivalent about the idea.  I tend to think that
> accepting options in any position is generally expected behaviour, and
> anything programmatically adding commands to pasta should routinely
> insert a "--" (that's certainly what I do in testing code).

Sure, on the other hand it's convenient when you're quickly trying out
ip -6 route show, or some command where "--" would add 10% of typing or
so.

> But, that's not a particularly strong opinion, so whatever.
> 
> The implementation looks more complex than necessary, though.  AFAICT
> if you just add a '+' to the front of the optstring it will do exactly
> what you want without having to juggle the first_nonopt and other
> variables.

Oops, that's actually the first approach I considered, but I didn't see
any guarantee that optind would assume the expected value after the
loop. However, it does... sending v3.

-- 
Stefano