Re: [Xen-devel] [PATCH] xen/pygrub: grub2/grub.cfg from RHEL 7 has new commands in menuentry.

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2014-01-30 at 14:32 +0000, M A Young wrote:
> On Thu, 30 Jan 2014, Ian Campbell wrote:
> 
> > On Thu, 2014-01-30 at 13:02 +0000, Joby Poriyath wrote:
> >> On Thu, Jan 30, 2014 at 12:07:34PM +0000, Ian Campbell wrote:
> >>> On Thu, 2014-01-30 at 12:01 +0000, Joby Poriyath wrote:
> >>>>>> @@ -394,7 +396,7 @@ class Grub2ConfigFile(_GrubConfigFile):
> >>>>>>                  continue
> >>>>>>
> >>>>>>              # new image
> >>>>>> -            title_match = re.match('^menuentry ["\'](.*)["\'] (.*){', 
> >>>>>> l)
> >>>>>> +            title_match = re.match('^menuentry ["\'](.*?)["\'] 
> >>>>>> (.*){', l)
> >>>>>
> >>>>> Why is this necessary? fedora-19 also have the aformentioned "--class
> >>>>> red, --class gnu" yet is parsed happily.
> >>>>
> >>>> A menuentry from RHEL 7 looks like this...
> >>>>
> >>>> menuentry 'Red Hat Enterprise Linux Everything, with Linux 
> >>>> 0-rescue-af34f0b8cf364cdbbe6d093f8228a37f' --class red --class gnu-linux 
> >>>> --class gnu --class os $menuentry_id_option 
> >>>> 'gnulinux-0-rescue-af34f0b8cf364cdbbe6d093f8228a37f-advanced-d23b8b49-4cfe-4900-8ef1-ec80bc633163'
> >>>>
> >>>> So we need 'lazy' match with '.*?'.
> >>>
> >>> ".*" already matches zero or more characters, so I'm not sure what ".*?"
> >>> means in addition to that, do you have a reference?
> >>
> >> http://docs.python.org/2/howto/regex.html#greedy-versus-non-greedy
> >
> > Thanks, pure punctuation is a bit tricky to for a search engine...
> >
> >>> Perhaps ["\']([^"\']*)["\'] is more accurate (i.e. disallow quotes in
> >>> the name itself, although you might have to split into handling " and '
> >>> separately to be more correct
> >
> > Any thoughts on this?
> 
> I went for ["\']([^"\']*)["\'] in a patch I added to Fedora pygrub in May 
> last year. That seems to work fine for recent Fedora versions which will 
> be somewhat similar to RHEL 7.

Oops, sorry, did I manage to drop that patch on the ground?

Ian.


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