[OE-core] Why is systemd installed to / (was: [yocto] Export bitbake variables between recipes)

[Mark Hatle]

On 12/3/14, 9:36 AM, Peter Kjellerstedt wrote:
>>> Can anyone please explain why OE-core installs systemd to / rather
>>> than /usr? Because I have traced the recipe all the way back to its
>>> introduction in OE classic, and I cannot find any rationale for
>>> this odd decision. And it is extra weird given the systemd authors'
>>> agenda that everything should be in /usr (and /etc)...
>>
>> It's only strange compared to Fedora.  We're not Fedora.. and I've
>> got systems that need to boot from a small '/' before mounting '/usr'.
>
> Speaking of Fedora, would an official image feature, e.g., "unified-fs",
> be acceptable for OE-Core that sets up the file system with /bin, /sbin
> and /lib* as links to their /usr counterparts? That would alleviate our
> problems with the differences in how systemd is installed.

The system permits developers to set the paths for the various pieces.  To get a 
Fedora like unified filesystem, you could do something like:

* provide your own fs-perms.txt:

/usr/bin	link	${base_bindir}
/usr/sbin	link	${base_sbindir}
/usr/lib	link	${base_libdir}

Then in your local.conf:

bindir = "${base_bindir}"
sbindir = "${base_sbindir}"
libdir = "${base_libdir}"


This will result in /usr/bin, sbin and lib being linked to /bin, /sbin, /lib -- 
and all of the package produced for your configuration will only reference '/'.

This isn't that unusual of a configuration from what I've been told.

--Mark

>> (In prior discussions we've made the decision to not fix every library
>> or application, but there is a warning you can enable that will show
>> you what libraries and applications live in '/' but have obvious
>> linkage to '/usr'.)
>>
>>>> (Another alternative is pkg-config, but I don't think that really
>>>> applies in this situation.)
>>>
>>> Nope.
>>>
>>>> Cheers,
>>>> Paul
>>>>
>>>> --
>>>>
>>>> Paul Eggleton
>>>> Intel Open Source Technology Centre
>>>
>>> //Peter
>
> //Peter
>