[oe] update-alternatives for ifplugd?

[Bryan Evenson]

All,

This is related to the ifplugd patch thread from a few weeks ago, which you can find here: http://lists.openembedded.org/pipermail/openembedded-devel/2014-May/095751.html.  Even though this relates to that thread, I figured the question was different enough to warrant a new thread.

I plan on using ifplugd on my system.  Connman with its dependencies added about 5 MB to my image and I couldn't justify the added space when a smaller application would do the same job for us.  I have tried using the ifplugd applet with Busybox without success, but the full ifplugd package generated with the recipe in the previously reference thread works for me.  However, since Busybox can be used as ifplugd depending on its configuration, I'm assuming it'd be best to have an update-altermatives reference in this ifplugd recipe.  After reading the Yocto documentation and seeing some examples, I still don't understand how update-alternatives works and how to use it in this recipe.

There is a real world scenario that I'm trying to handle.  I had some releases in which Busybox had the ifplugd configuration option included, but that is no longer the case. If a firmware upgrade installed the full ifplugd package and upgraded Busybox to no longer include ifplugd, the ifplugd binary would not exist in /usr/bin.  I think the Busybox upgrade would delete the no-longer needed softlink to /usr/bin/ifplugd, but this would occur after the ifplugd package was installed.  Would the proper update-alternatives reference in this recipe fix this scenario?

Regards,
Bryan