Hi Darren,

thank you for your comments.

Please see my response in line.

Jan


On 05/30/12 15:07, Darren Kenny wrote:
Hi Jan,

On 30/05/2012 12:59, Jan Damborsky wrote:
Hello caimaniacs,

I am currently evaluating following net text install bug (which is
in fact regression I caused when fixing 7162079):

7172606 Network text install fails trying to download /etc/shadow

I have some idea how it could be addressed, but since this particular
issue seems to reveal more generic kind of problem, I would like to
verify if approach I am considering seems reasonable. Concurrently
I am working on related code changes in order to find out if that approach
is feasible or not.

Please see proposal below.

Thank you very much,
Jan


Background
==========
In cases when CPIO transfer method is used for populating installation
target, there are files which need to be reverted to their
pristine state on target (shadow(4) being one of examples).
Those files are stored within dedicated "save area" during process
of media construction. Then during installation they are transferred
to appropriate places by CleanupCPIOInstall ICT task.

In case of media boot (text installer, GUI installer), those files reside
under /.cdrom/save directory while in case of network boot (text installer
only) they are downloaded file-by-file from AI server to /tmp/ directory,
then copied to the target.

Problem statement
=================
In general, "save area" may contain files with restrictive combination
of ownership/permissions. That turned out to be problematic in case
of net boot when files are transferred one by one by webserver running
under webservd user. In particular, webserver currently fails to
transfer shadow(4) file, since it's root readable only.

Proposed solution
=================
Since "save area" may contain files webserver may not be able to access
directly, I am wondering if instead transferring those files separately,
if it may make sense to transfer them in form of archive, then unarchive
them on target.

In particular, I am thinking if "save area" may be delivered by
existing solarismisc.zlibarchive. /.cdrom/save would be just symlink
to perhaps /mnt/misc/save directory which would contain populated
"save area".

Advantages of this approach:

- solarismisc.zlibis standard archive delivered in all scenarios.
    Thus, consistent approach could be used for all types of installations,
    no need to distinguish between net boot and media boot. Related pros:
    - simplified code
    - simplified test matrix


Looking for the least-change approach, I'm wondering that given that these
files are being served by the webserver, can they not just be made open for
reading by the webserver? It's not as if they contain any significantly
restricted content at this point in time - the main thing is to ensure they
have the correct permissions on the client side...

Yeah, I agree those are pristine files which do not carry any secret.
However, that would mean we would still need to keep two mechanisms for
handling 'save area' (one for net boot, one for media boot) which
is something I think it is worth to eliminate.



But, that said, I do like the idea of transferring them in an archive,
where possible, and it wouldn't seem to be that big a change either, since
the files are copied to the save dir by DC in the pre_pkg_img_mod
checkpoint, which is run before pkg_img_mod that creates the zlib files.

Yep, I agree.

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