[OE-core] [PATCH] wic: Generate startup.nsh for EFI cases if none found

[Ed Bartosh]

On Thu, Sep 28, 2017 at 01:44:29PM -0400, Tom Rini wrote:
> On Thu, Sep 28, 2017 at 06:47:07PM +0300, Ed Bartosh wrote:
> > On Wed, Sep 20, 2017 at 12:03:27PM -0400, Tom Rini wrote:
> > > In the case of non-wic images there is logic today to generate a
> > > startup.nsh file that will be executed by EFI to run the loader that the
> > > image contains.  In the WIC case is currently depends on that file being
> > > generated elsewhere and placed in DEPLOY_DIR_IMAGE and only used if
> > > present there.
> > 
> > What's wrong with this approach?
> 
> No one ever provides a startup.nsh and everyone that wants one creates
> the same one line trivial example.  The end result is that no WIC images
> are Just Bootable on UEFI systems unless you first go and spell that out
> as the desired booting device.  This isn't an awesome workflow which is
> why the non-WIC cases make the required startup.nsh :)

Would it be better if EFI providers create this file?

I still believe that wic should't hack the filesystem content unless
it's really unavoidable. So far I know only one exception: updating
/etc/fstab. And even that is not always needed (see --no-update-fstab
patchset for further details.)

> 
> > I'd be happy to make wic to do only partitioning and assembling the
> > image and avoiding to modify image content as much as possible.
> > That would make wic design much more clear and let us to remove
> > a lot of duplication between wic and meta/classes code.
> > 
> > Regarding boot partition content, I think preparing it from bootfs
> > directory the same way as it's done for root partition is the way to go.
> > You can find more details about it here:
> > https://bugzilla.yoctoproject.org/show_bug.cgi?id=10073
> 
> I don't conceptually see a problem with going that route.  But today WIC
> images aren't nearly as useful as they could be, with a rather tiny
> change.
> 

If we agree that wic should avoid modifying content then the obvious way
to solve this is to provide required content (startup.nsh in this case)
either by EFI related recipes or core classes.

> My patch is also a regression-fix, I believe, in that at some point in
> the past, when Christopher's patch went in, things were laid out such
> that startup.nsh was often/always generated by another class and placed
> where WIC would find it and copy it in.  At some point that was
> broken/changed, and no one noticed / was interested enough to fix it.
>

If this functionality is covered by wic test suite this wouldn't
happen.


--
Regards,
Ed