On Sun, Sep 04, 2005 at 04:02:52AM +1000, matthew green wrote:
> BTW: "/../" references the real root for emulations.  no need to
> remount root inside the chroot twice.

	It only does that because the CHECK_ALT_* has that hack in there.
If the overlay+chroot method were to actually be implemented, I'd expect
all the CHECK_ALT_* code, and many of the syscall wrappers that do only
that, to go away.

> i'm really against using special mount points or chroots to get
> emulations working.  it's not clear it can be done well or safely
> and it adds extra work for the sysadmin to support emulations.
> it shouldn't need any more help that having /emul/linux populated.

	IMO, using a consistent and well known approach to modifying how the
filesystem appears to a process would go a long way towards improving
safety by allowing the sysadmin to think about the behaviour of emul'd
processes in a way that he's probably familiar with due to setting up
chroot environments for things like named, ftpd, etc...

	Setting up linux emul _already_ requires changes to fstab to
mount procfs.  I think the benefit of having the altered view of the
filesystem in /emul explicitly configured and having the results of
that _visible_ to the system admin even when using non-emul'd programs
outweighs the drawback of needing to take an extra step to configure
the mount.

eric