[oe] Upgrading files identified as CONFFILES?

[Paul Barker]

On 6 November 2014 15:28, Bryan Evenson <bevenson at melinkcorp.com> wrote:
> Paul,
>
>> -----Original Message-----
>> From: openembedded-devel-bounces at lists.openembedded.org
>> [mailto:openembedded-devel-bounces at lists.openembedded.org] On
>> Behalf Of Paul Barker
>> Sent: Thursday, November 06, 2014 9:36 AM
>> To: OE Devel
>> Subject: Re: [oe] Upgrading files identified as CONFFILES?
>>
>> On 6 November 2014 14:06, Bryan Evenson <bevenson at melinkcorp.com>
>> wrote:
>> > All,
>> >
>> > First, please let me know if I should be directing this to a different OE/yocto
>> mailing list; I have a hard time figuring out which list is appropriate at times.
>> >
>> > I am on poky/dylan and am using NTP on my target system.  I would like to
>> change the configuration for NTP and push out the changes to devices that
>> are firmware upgradable.  I made the change and pushed out the upgrade,
>> but I see that ntp.conf did not get changed on at least one of the systems
>> (the first one I checked).  Now I see that ntp.conf is listed under CONFFILES
>> in the main ntp recipe (http://www.yoctoproject.org/docs/1.7/mega-
>> manual/mega-manual.html#var-CONFFILES), which explains why it was not
>> upgraded.
>> >
>> > First, I want to confirm how the CONFFILES parameter works.  If a file is
>> listed under CONFFILES, is that file never modified during an upgrade or is it
>> only upgraded if it has not been modified (matches the default file from the
>> previous package version)?  I am using opkg for package management if that
>> makes a difference.
>> >
>> > Second, how do I force the NTP configuration to be upgraded?  For my
>> system, the user has no interface to modify the NTP configuration.  So even
>> though it is a configuration file, in my case I want ntp.conf to always match
>> the version provided by the upgraded package.
>> >
>> > Thanks,
>> > Bryan
>> >
>>
>> This largely depends on the package manager. I can tell you how opkg
>> works... If a file is listed in CONFFILES it is backed up before an update is
>> applied. By default, if a conffile has changed, the new changes go into a file
>> named "%s-opkg" where %s is the original file name. If "--force-maintainer"
>> is passed as an argument or the option "force_maintainer" is set, the new
>> changes overwrite the version in the file system. In opkg v0.3.0 there will be
>> a new "--ignore-maintainer" argument and "ignore_maintainer" option to
>> keep the conffile unmodified but not store the changes in "%s-opkg".
>>
>> Hope that helps,
>>
>
> Thanks for the detailed explanation.  And just to explore my options, if I were to add the following in my ntp bbappend:
>
> CONFFILES_${PN} = ""
>
> would that remove ntp.conf from the CONFFILES list and force the configuration to be updated each time it changes?
>
> Thanks,
> Bryan

It looks like the list of CONFFILES is taken from the version of the
package being installed. So if a file is listed in CONFFILES for the
old version but not the new version, it won't be treated as a conf
file and should just be overwritten.

This isn't a behaviour I've looked at in detail so please let me know
if it works.

Thanks,

-- 
Paul Barker

Email: paul at paulbarker.me.uk
http://www.paulbarker.me.uk