[OE-core] meta/lib/oe/rootfs.py: dont' remove any packages by default

[Paul Eggleton]

Hi Robert,

On Friday 31 July 2015 14:56:15 Robert Yang wrote:
> Currently, the rootfs.py removes base-passwd, shadow, update-rc.d,
> update-alternatives and run-postinsts when package-management not
> in IMAGE_FEATURES, this causes two problems:
> 
> 1) This makes we can't install the removed pkgs to rootfs, such as
>     IMAGE_INSTALL_append = " shadow", the shadow can't installed (first
>     installed, then removed)
>
> 2) The base-passwd has been removed, but the /etc/passwd and /etc/group
>     are still existed since they are generated by preinst, this would
>     confuse the user, and we can't add a postuninst to remove /etc/passwd
>     and /etc/group since they are required when runtime.
>
> I think that we should not remove any pkgs by default, we can add some
> interfaces/ways to let the user decide whether to remove them or any
> other pkgs, for example, add a REMOVE_PACKAGS variable, leave it as NULL
> or only add run-postinsts to it by default.

There is a reason for these not to be there by default when you don't have 
runtime package management - the assumption is you won't be adding or removing 
any users, thus the binaries that those packages install aren't needed.

Now, it might be argued that if for example you're using some non-package-
management based application installation mechanism that has per-application 
users (Android does this) you will need to add and remove users and therefore 
you do still need those tools, in which case we would probably need a 
mechanism for preventing the removal of those packages. I'm not sure whether 
that would be an IMAGE_FEATURES item (e.g. "user-management"), or perhaps we 
just make this code get the value of a variable specifying the list of 
packages to remove instead of it being hardcoded as it is now. Either way 
though I think the default behaviour does make sense for most people and I 
don't think we ought to be changing that part.

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre