[systemd-devel] Antw: [EXT] Re: Using timedatectl on a readonly rootfile system using mender

[Ulrich Windl]

>>> Shravan Singh <shravan at bluesparq.com> schrieb am 20.08.2020 um 20:22 in
Nachricht
<CABjzrPTf8PtZ24_KOZ-xd8BDdJC0DhgWTaEnCdX1JDSCAujcPw at mail.gmail.com>:
> Hello Andrei,
> 
> Thank you for your email. Yes, People have been telling me this:
> 
> *Changing timezone globally requires changing /etc/localtime link which
> requires writable /etc. *
> 
> But no one is telling how to resolve my issue with a read-only rootfs.
> There are other files which can be overwritten in /etc that are linked to a
> file in /run directory for eg /etc/resolv.conf file.
> Then why not /etc/localtime. Why is localtime guarded so much

I guess this is due to the fact that a PDP 11 really wasn't a mobile computer;
thus the system timezone was not expected to change every boot. ;-)

> I refuse to believe that I am the only person facing this problem. But I
> did find some leads now. Will keep you posted

Traditionally /etc (thus rootfs) is writable. No problems. Making it
read-only, you create a problem.

> 
> But thank you so much for your response
> 
> Regards,
> Shravan Singh
> (239) 243-0838
> 
> Blue Sparq, Inc.
> 928 NE 24th Lane unit 4 and 5.
> Cape Coral, FL 33993
> 
> IMPORTANT: The contents of this email and any attachments are confidential.
> They are intended for the named recipient(s) only. If you have received
> this email by mistake, please notify the sender immediately and do not
> disclose the contents to anyone or make copies thereof.
> 
> 
> On Thu, Aug 20, 2020 at 2:00 PM Andrei Borzenkov <arvidjaar at gmail.com>
> wrote:
> 
>> 20.08.2020 18:55, Shravan Singh пишет:
>> >  Hello,
>> > I have raspberry-pi cm3 which is running an embedded yocto poky linux
>> > warrior branch with mender.
>> >
>> > I have made my rootfs as read-only because of which I am not able to use
>> > timedatectl to change the system time zone.
>> >
>> > I was looking through the c code which makes me think that even if I did
>> > create and change symlink to point to a file in a read and write
location
>> > of the memory. It won't make any difference.
>> >
>>
>> Changing timezone globally requires changing /etc/localtime link which
>> requires writable /etc.
>>
>> > I looked into the file timedated.c and here is where I wanted some help.
>> I
>> > see the line
>> > * r= get_timzeone()* in the function *context_read_data* all I want to
>> know
>> > is where is *get_timezone* defined and how is it calling
*/etc/localtime*
>> >
>>
>> src/basic/time-util.c
>>
>> grep is wonderful tool.
>>
>> > Any help will be appreciated. I have raised questions everywhere and I
am
>> > not getting any help at all.
>> >
>> > And I am not an embedded developer. This place is my last cry for help
>> > Regards,
>> > Shravan Singh
>> > (239) 243-0838
>> >
>> > Blue Sparq, Inc.
>> > 928 NE 24th Lane unit 4 and 5.
>> > Cape Coral, FL 33993
>> >
>> > IMPORTANT: The contents of this email and any attachments are
>> confidential.
>> > They are intended for the named recipient(s) only. If you have received
>> > this email by mistake, please notify the sender immediately and do not
>> > disclose the contents to anyone or make copies thereof.
>> >
>> >
>> > _______________________________________________
>> > systemd-devel mailing list
>> > systemd-devel at lists.freedesktop.org 
>> > https://lists.freedesktop.org/mailman/listinfo/systemd-devel 
>> >
>>
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