Stéphane Graber [2013-09-24 13:57 -0000]:
> So I think your best bet here is to change those daemons to fallback
> to in-place file content changes when atomic edits fail because of
> writable fs.
As I wrote above that can only be a workaround hack. Changing such
kind of files inline is a source of race conditions and program
crashes, not a solution.
> If /etc/localtime is already a symlink in the rootfs, you should be
> able to change its target without much trouble too.
Not if it points to a file in /usr/share/zoneinfo/... You don't want
to change the contents of the target file, but you want to change the
symlink itself to a new target. But the latter again doesn't work on
an r/o file system, so we'd need some intermediate file like
/etc/localtime → /data/localtime → /usr/share/zoneinfo/...
Stéphane Graber [2013-09-24 13:57 -0000]:
> So I think your best bet here is to change those daemons to fallback
> to in-place file content changes when atomic edits fail because of
> writable fs.
As I wrote above that can only be a workaround hack. Changing such
kind of files inline is a source of race conditions and program
crashes, not a solution.
> If /etc/localtime is already a symlink in the rootfs, you should be
> able to change its target without much trouble too.
Not if it points to a file in /usr/share/ zoneinfo/ ... You don't want zoneinfo/ ...
to change the contents of the target file, but you want to change the
symlink itself to a new target. But the latter again doesn't work on
an r/o file system, so we'd need some intermediate file like
/etc/localtime → /data/localtime → /usr/share/