[oe] update-alternatives problems

[Rodrigo Vivi]

Hi all,

I have some doubts about the update-alternatives scheme.

Why to have 2 ways to create an update-alternatives entry in the
postinst script? One is setting ALTERNATIVES_* variables inheriting
the update-alternatives.bbclass and the other is to write the function
 pkg_postinst_${PN} () containing the update-alternatives commands.
What is the big difference?

For example in sysvinit_2.86.bb there are both methods.
ALTERNATIVES_* for init
and the function for {halt,reboot,shutdown,last,mesg,wall}

I believe that there is a good reason for that, but what I believe
that is wrong is:

when using the ALTERNATIVES_* the path is ritght like in the init case
ALTERNATIVE_PATH = ${base_sbindir}/init.sysvinit
so this is the right update-alternatives command in postinst script:
update-alternatives --install /sbin/init init /sbin/init.sysvinit 50

But when in function the path are wrong (it aren't complete):
update-alternatives --install ${base_sbindir}/halt halt halt.${PN} 200
So the line in postinst script is that:
update-alternatives --install /sbin/halt halt halt.sysvinit 200
instead of a complete one
update-alternatives --install /sbin/halt halt /sbin/halt.sysvinit 200

Someday in past I've noticed that all of my links of
update-alternatives was broke  because this incomplete path so I did a
patch to update-alternatives-dpkg package to take the begin of path
(/sbin) for the link one (/sbin/halt) generating a path link
/sbin/halt.sysvinit fixing all cases that I knew. It was working fine
until today when I saw that my init link was pointing to
/sbin//sbin/init.sysvinit and breaking my initialization.

I believe that you don't have this error because update-alternatives
of ipkg works different, right?

What do you believe that is better? change all bb to have a standard?
or code a patch of my patch to make update-alternatives-dpkg check if
the path is right before try to get the begin of the link?

Regards

Rodrigo Vivi
INdT - Instituto Nokia de Tecnologia
Blog: http://blog.vivi.eng.br
GPG: 0x905BE242 @ wwwkeys.pgp.net