/etc readonly

[Marius Gedminas]

On Thu, Aug 06, 2009 at 01:15:30PM +0200, Siggy Brentrup wrote:
> On Thu, Aug 06, 2009 at 12:38 +0200, Carl Friis-Hansen wrote:
> > 
> > On Thu, August 6, 2009 10:48, Siggy Brentrup wrote:
> > > On Thu, Aug 06, 2009 at 10:30 +0200, Luca Ferrari wrote:
> > >> Hi all,
> > >
> > >> a trivial question: when the system loads the / in read-only, how
> > >> can the system keep updated the /etc/mtab file?
> > >
> > > I doesn't, there's still the mtab in kernel space that's
> > > kept up to date.
> > 
> > The file /etc/mtab *is* writable by root.
> 
> Thanks for correcting me.  After all the kernel is free to ignore soft
> ro settings.  Must have been an old *nix version that mislead me.
> After rethinking the only version I'm sure about /etc/mtab not being
> updated while / is mounted ro is Unix release 6 and that's really
> ancient.

No, you were right: when / is mounted read-only, even root is unable to
write to /etc/mtab.

/proc/mounts is always up-to-date, though, even though it lacks some of
the information present in /etc/mtab

Marius Gedminas
-- 
I need a word processor on my laptop like I need a Selectric typewriter in my
laptop bag.
        -- Don Marti
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