Re: klibc

H. Peter Anvin
2006-06-09T18:45:52Z

Followup to: <8764ja7o2d.fsf@hades.wkstn.nix>
By author: Nix <nix@esperi.org.uk>
In newsgroup: linux.dev.kernel
> >
> > You shouldn't pivot_root the rootfs filesystem.
>
> What happens if you do? I mean, it doesn't make even conceptual sense,
> really. The rootfs is always there: that's its entire purpose.
>

"What happens if you do"... well, it may work, it might not, it may
break some functionality for you or break in a future kernel version.
It's undefined behaviour.

> > Use the run-init
> > utility or something similar instead (which does a mount with
> > MS_MOVE.)
>
> busybox has a switch_root tool which (conceptually) rm -rf's everything
> on the root filesystem and then does such a mount. (After all whatever
> is on that filesystem is inaccessible after the overmount, so keeping
> it around is just a waste of memory.)

What busybox calls switch_root is the same as the run-init tool from
the klibc distribution.

-hpa