[OE-core] Prelink problem

[Richard Purdie]

On Tue, 2019-01-08 at 14:50 -0600, Mark Hatle wrote:
> On 1/8/19 2:37 PM, Burton, Ross wrote:
> > On Tue, 8 Jan 2019 at 20:15, Mark Hatle <mark.hatle at windriver.com>
> > wrote:
> > > > No idea why the opkg rootfs code is doing prelink operations
> > > > when RPM
> > > > or dpkg don't.   CCing Mark who may have an idea here.  I
> > > > thought the
> > > > autobuilder exerised multilib-on-opkg, but maybe not.
> > > 
> > > They all should be doing prelink operations.  The operation
> > > SHOULD be
> > > generically implemented as part of the image-prelink class, which
> > > is where I
> > > would have expected that copy to exist.
> > > 
> > > If any of the package types of specifically doing something, that
> > > sounds
> > > broken...  but the generic ones (last I looked) said to copy in
> > > the config file
> > > [if it didn't exist], run prelink, remove the file [if it wasn't
> > > there to start
> > > with].
> > 
> > Note that it's part of the incremental code, so needs to be in the
> > rootfs code directly I suspect. Frankly I'd love to see incremental
> > images removed.  It makes promises it can't keep (the moment a
> > rootfs
> > postprocess command is used, all bets are off) and massively
> > complicates things.
> 
> We assume the post process command is what an 'admin' would do.  So
> the various
> package managers should be able to deal with it in most
> cases.  (Note, obviously
> it's more freeform, but I wouldn't expect everything to work in you
> removed a
> large part of the filesystem for instance.)
> 
> As for prelink, I'm surprised this is in the incremental code.  I'm
> not sure why
> it would be necessary unless the incremental work wants to UNPRELINK
> the rootfs
> before performing the upgrade?
> 
> Prelink itself should still be run as a postprocess command that
> takes the
> output of the filesystem and reprocesses it.
> 
> So something seems out of sync here.. (at a minimum probably should
> be better
> commented on why it's needed..)

The code is there for incremental opkg multilib image support. Its
trying to compare whether binaries are identical. To make it work, it
has to "unprelink" the files first before comparing.

I'm not convinced this is a good idea :/. I'm wondering if incremental
image generation makes sense at all in this context to be honest.

Cheers,

Richard