Re: [Qemu-devel] [PATCH] do not chdir(/) in qemu-nbd

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Jan 13, 2012 at 04:47:35PM +0400, Michael Tokarev wrote:
> On 13.01.2012 15:57, Stefan Hajnoczi wrote:
> > On Fri, Jan 13, 2012 at 9:04 AM, Michael Tokarev <mjt@tls.msk.ru> wrote:
> >> When qemu-nbd becomes a daemon it calls daemon(3) with
> >> nochdir=0, so daemon(3) changes current directory to /.
> >> But at this time, qemu-nbd did not open any user-specified
> >> files yet, so by changing current directory, all non-absolute
> >> paths becomes wrong.  The solution is to pass nochdir=1 to
> >> daemon(3) function.
> > 
> > It's polite to chdir("/") so that file systems can be unmounted (even
> > more important when chroot was involved, but I think qemu-nbd doesn't
> > do that).  Is it possible to manually do a chdir("/") later on after
> > we've opened necessary files?
> 
> Yes that was something I wasn't happy about too -- lack of chdir(/) in
> daemons is annoying.
> 
> But instead of adding a chdir later, I'll try to rearrange code a bit
> to do all init in the parent instead.

Or just canonicalize all relative paths before daemonizing.


Daniel
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