Re: Making syspkgs and makefs play nice together

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

On 15/05/2009, at 12:09 PM, David Young wrote:
> Just in case it will save you some trouble, let me tell you how I  
> filter
> uninteresting syspkgs from the metalog that 'build.sh distribution'
> creates before I pass that metalog to makefs.  I have used only host
> tools (i.e., not pkg_add) and avoided hacking on some thorny C code.
>
> First I come up with regular expressions that match the syspkgs that
> I want to omit from the installation sets (base, etc, ...) that
> interest me:

Hmm, I used shell wildcards, but I wasn't thrilled with it. I used the  
shell to expand the wildcards, and I wanted to minimise the chances of  
blowing out command line length limits, so I had to play a few games  
with cd. Regexps work at least as well, and mean I could implement it  
with a tool that wasn't going to blow up on a long list.

My first cut at this had a list of packages to include and then a list  
of packages to exclude from the former list. This let me say things  
like include base-* and etc-*, but exclude base-kernel-modules.

> To find the precise syspkgs to omit, I use those regular expressions  
> to
> filter the list of packages in each installation set[1], first.  Then
> I expand that list by adding to it all of the syspkgs that depend on
> a package[2] that is already in the list: in this way, if etc-atf-etc
> depends on the omitted package base-atf-bin, then etc-atf-etc will be
> omitted, too.

I implemented the dependency checking for inclusion, but didn't  
realise it would be a good idea for exclusion as well.

> I pass the PLIST of each syspkg[3] on my omissions list through a  
> simple
> awk script that turns the PLIST to a list of files.  I take those  
> files
> out of the metalog that 'build.sh distribution' writes to $DESTDIR/; I
> feed the remainder of the metalog to makefs(8).

I interrogate the package files directly. I have updated pax to output  
mtree format listings on request, analogous to it's ability to accept  
mtree listings as input. Easiest piece of C code I've ever written. As  
my scripts stand right now, I can build filesystem images directly  
from the syspkgs in $RELEASEDIR without reading anything out of  
$DESTDIR (that it doesn't write there first). And it's fast. I was  
expecting to make the machine grind a bit as worked it's way through  
base-*, but it finished so quickly I had to double check the size of  
the output image.

I mentioned earlier that I'm a bit ambivalent about the shell  
wildcards and how I've implemented them. That isn't true for this bit.  
It's one of those solutions that just seems to all fit together. It's  
not perfect yet, but it's simple and well behaved.

Cheers,
Lloyd