Re: sharedlocalstate default - does anybody use this?

[Eric Blake]

On 06/06/2018 07:09 AM, Mariano, Adrian V. wrote:
> It has been brought to my attention that in my package (GNU units) I have a 
> file that gets changed every day located in datarootdir---but this location is 
> for read only files.
>
> The correct place for my architecture independent dynamic file would appear to be  
> sharedstatedir.   However, this resolves to the rather bizarre path /usr/local/com.  I 
> can't find any reference to anybody actually using this path.   Do all the distributions 
> over-ride this into something "normal"?

Distros are not allowed to install into /usr/local.  So a default of 
/usr/local/com is irrelevant to them - but still relevant to a 
non-distro build.

>  The fedora units guy tells me it will be /var/lib, for example---and I think 
> with redhat the whole /usr directory is supposed to be read only.

Top-level /usr might be read-only, but distros don't control /usr/local.

> So what's the correct practice for my package?  Should I use sharedstatedir and 
> not worry about it resolving to a strange default path because mostly it will 
> get changed by site defaults?

Correct.  Under the /usr/local hierarchy (when you install the software 
yourself as an add-on to the distro packaging), /usr/local/com is better 
than any other alternative, for still being located within a single 
hierarchy under your control. But under the /usr hierarchy (when the 
software is installed on your behalf by the distro), /var/lib is correct 
- but that's WHY './configure --sharedstatedir=/var/lib' exists, and 
distros are responsible for setting it.

>  Or is there some other way to handle this?

No, as long as you use sharedstatedir correctly, then you don't have to 
take care of anything further.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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