[OE-core] how to set time zone

[Andrea Adami]

On Wed, Nov 2, 2011 at 8:15 PM, Mark Hatle <mark.hatle at windriver.com> wrote:

> On 11/2/11 12:32 PM, Andrea Adami wrote:
> > On Mon, Oct 31, 2011 at 1:44 AM, Ni Qingliang <
> niqingliang at insigma.com.cn
> > <mailto:niqingliang at insigma.com.cn>> wrote:
> >
> >     I'd like the 'system level configuration' solution.
> >
> >     the /etc/localtime/ link can be done when packaging rootfs (using the
> >     system level configuration).
> >
> >     On Fri, 2011-10-28 at 22:43 +0800, Mark Hatle wrote:
> >     > Setting the default TZ for the image is something that should be
> done in a
> >     post
> >     > install script for the tzdata package or something similar.
> >     >
> >     > Since the /etc/localtime is usually a copy/hardlink or symlink to
> the timezone
> >     > data we don't want to package it up.  Instead we want to perform
> the actions
> >     > that a program running on the target system itself would use to
> change the
> >     timezone.
> >     >
> >     > So I think the easiest approach is to add a system level
> configuration
> >     variable
> >     > (set the default).
> >     >
> >     > Then use this variable to populate the configuration file that
> specifies the
> >     > system timezone... and then use the post install process to check
> the contents
> >     > of a text file.
> >     >
> >     > Alternatively do this via an initscript -- but for folks w/
> read-only
> >     > filesystems I'm not sure that will work.
> >     >
> >     > --Mark
> >
> > <cut>
> >
> > Maybe I misunderstand "system level configuration" but in the meta-oe
> recipe we have
> >
> > DEFAULT_TIMEZONE ?= "Europe/London"
> >
> > Maybe UTC would be better?
>
> To me no timezone (which is UTC) is preferable as the system designer can
> then
> set the timezone, externally to the package(s).
>
> > Note how the variable is weak thus can be overridden in local.conf.
> >
> > Secondly, why do it as post-install or at image do_rootfs stage when we
> have set
> > the variable and are therefore able to provide sane defaults in
> do_install?
>
> If it's done within a do_install, then the file (/etc/timezone) itself gets
> placed into the package.  If it's in the package, then if/when someone
> upgrades
> the package from a feed the timezone gets reset to the previous value.
>  That's a
> bug IMHO.
>

Sure, I overlooked that!


> If it's done as a post-install script, then the timezone configuration can
> be
> evaluated and if one isn't set -- or there is no timezone file -- then we
> can
> set it to UTC or a similar default timezone.. (the value in the
> DEFAULT_TIMEZONE
> variable is reasonable in this approach.)
>
> maybe "Factory" then?
See post-install script example:
http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/sys-libs/timezone-data/timezone-data-2011k.ebuild


> > Other points before starting to write a patch:
> > -why is the recipe in oe-core doing   chown -R root:root ${D}   ?
>
> There was an issue with the way the timezone data was
> extracted/constructed that
> it was have all of the build system's uid/gid preserved in the copy to the
> final
> install directory -- so when packaging incorrect usernames and groups were
> fed
> into the process causing issues.
>
> A simple chown -R root:root ${D} ensured that all of the timezone data was
> owned
> by the root user (on the target).
>
> > -the logic around   # libc is removing zoneinfo files from package
> >   Is it only eglibc?
>

> Timezone info is updated more often then the system libc.  So the zoneinfo
> files
> are handled externally of the libc.  This allows for easier updates over
> time..
> (This is my guess, as I'm not familiar with exactly what this comment
> refers to.)
>
> Comments in meta-oe recipe would suggest that apparently only eglibc is
removing zoneinfo file.

       # Only eglibc is removing zoneinfo files from package
        if [ "${LIBC}"x = "eglibc"x ] ; then
          cp -pP "${S}/zone.tab" ${D}${datadir}/zoneinfo
          cp -pP "${S}/iso3166.tab" ${D}${datadir}/zoneinfo
        fi


Being that we need the files on first boot, I'm not against providing
'Factory' settings during image do_rootfs or even in base-files.
The settings of timezone and locale (and keyboard) are typically done by
user on first boot, at least in graphical environments.

Thanks for your comments!

Regards


Andrea
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