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

[Mark Hatle]

On 5/24/13 3:52 AM, Paul Eggleton wrote:
> 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 at 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.

Yes this would be the same issue.  I'm really not sure how to do this 
automatically as it requires knowledge that the recipe has plugins, and that the 
plugs are ABI/lib specific.

I'm definitely open to suggestions.

--Mark

> Cheers,
> Paul
>