Re: [PATCH] libpam: fix multilib packaging issue for pam-plugins

[Paul Eggleton <paul.eggleton@linux.intel.com>]

On Thursday 23 May 2013 09:40:51 Mark Hatle wrote:
> On 5/23/13 3:01 AM, Ming Liu wrote:
> > libpam might miss ABI specific dependencies for pam-plugins-*, for RPM
> > uses
> > generic names to check the packages depending on it and doesn't consider
> > the arch, which will lead to packaging issues in multilib build.
> > 
> > pam_plugin_hook is added because the plugin packages are dynamically
> > generated, so we need to manually process multilib names by add baselib to
> > RPROVIDES/RDEPENDS as ABI specific tag.
> > 
> > [YOCTO #4532]
> > [ CQID: WIND00416824 ]
> > 
> > Signed-off-by: Ming Liu <ming.liu@windriver.com>
> 
> I worked with Ming Liu on this particular issue.  You may wonder why this is
> necessary let me attempt to explain the underlying causes.
> 
> In deb/ipk on a multilib package, the package name has specific multilib
> references in it.  I.e. the alternative libraries start with something like
> lib32-...  This was done primarily because deb/ipk do not allow two packages
> with the same name (but different architectures) to be installed at the
> same time.  So the name has to be unique.
> 
> In RPM however, the names of the packages and matches with the architectures
> and if they are not the same we can do these multilib installs.  This
> matches the behavior of other RPM based distributions and in many ways the
> tools people are used to working with RPM.  For the most part this works
> fine in multilib configurations because additional per-file dependencies
> are added that capture the shared library dependencies with ABI specific
> information.  This unfortunately fails in a few cases where plugins are
> dynamically loaded via dlopen -- such as libpam.
> 
> One possible fix is simply to follow the deb/ipk package naming, but this
> causes a design advantage of rpm.  When a package has a dependency on
> 'bash', we really don't care what bash is installed, only that -a- bash is
> installed.  In the deb/ipk case, the lib32- packages would end up with a
> lib32-bash dependency and you could potentially end up with two 'bash'
> packages being installed.
> 
> So the fix I recommended for the issue was to add the baselib path to the
> internal dependencies.  Since we know that the libpam installed in 'lib'
> needs the modules that were compiled to also work with the 'lib' version of
> libpam. While the libpam in 'lib64' need the modules to work with the
> 'lib64' version of the plugins.
> 
> Existing dependencies are preserved so there is no impact in the ipk/deb
> case, the RPM case is resolved as the additional dependency information is
> now present for the package manager to select the package we really want.
> 
> If anyone else has a suggestion for an alternative fix, we're interested --
> but this is the best answer we could come up with.  (If any of the above
> should be added to the commit message, the YP bug, or documentation, please
> let me know and I'll make sure it gets added.)

This is the same problem as bug 4408:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=4408

It's a bit nasty to have to solve this on a per-recipe basis; we need some 
kind of generic solution. At the moment I'm not sure what that would be 
however.

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre