Re: [Qemu-devel] [PATCH] linux-user: use realpath for emulation dir paths

[Paul Bolle <pebolle@tiscali.nl>]

On Fri, 2009-12-04 at 11:00 +0100, Arnaud Patard wrote:
> Riku Voipio <riku.voipio@iki.fi> writes:
> > On Fri, Oct 02, 2009 at 02:25:36PM +0200, Paul Bolle wrote:
> >> Note that I have some reservations about the current init_paths() and
> >> path() code:
> >> - their names seem to confusing. Maybe those should be init_base()and
> >> base() or something similar;
> >> - why does init_paths() copy all filenames in the emulation dir (at
> >> least, that what it seems to do)? Try something silly like
> >> "-L /home/../" to see what I mean ...
> >> - and why does path() return the original filename if that file isn't
> >> found in the emulation dir? That looks like a nice source for confusing
> >> behavior or crashes, as that means an identical named file (but using 
> >> the regular root) will then be used.
> >
> > Yeah, all that is a big mess and should be cleaned up. At the moment it
> > is all too easy to get init_paths to recurse forever..
> 
> fwiw, it should not be hard to prevent this dead loop. I have
> somewhere a patch avoiding going into /dev,/proc and it cured the
> problem. Of course, there may be some other places leading to deadloop
> but at least avoiding /dev and /proc would be a good start if one
> really wants to fix that.

It's been two months, so I have forgotten most details here, but why is
the init_path() step actually needed? Can't path() simply prepend the
name of emulation dir, if any, and return that (possibly unaltered)
path?

I guess the original path must be altered too (ie, it should point to
the newly created path and the original string should be freed). Can't
that be done reliably?


Paul