Re: [Patch resend v3 3/3] binfmt_misc: add F option description to documentation

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Tue, 2016-04-19 at 14:58 -0500, Serge E. Hallyn wrote:
> Quoting James Bottomley (James.Bottomley@HansenPartnership.com):
> > Signed-off-by: James Bottomley <
> > James.Bottomley@HansenPartnership.com>
> 
> Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
> 
> Thanks, James.  Which tree were you thinking this would go in
> through?

I'm happy to become binfmt_misc maintainer (on the grounds that last to
touch it gets to keep it) and thus run my own tree, but I talked to Al
at LSF/MM and he thinks it can go through the vfs tree.

James

> > ---
> >  Documentation/binfmt_misc.txt | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/Documentation/binfmt_misc.txt
> > b/Documentation/binfmt_misc.txt
> > index 6b1de70..ec83bbc 100644
> > --- a/Documentation/binfmt_misc.txt
> > +++ b/Documentation/binfmt_misc.txt
> > @@ -66,6 +66,13 @@ Here is what the fields mean:
> >              This feature should be used with care as the
> > interpreter
> >              will run with root permissions when a setuid binary
> > owned by root
> >              is run with binfmt_misc.
> > +      'F' - fix binary.  The usual behaviour of binfmt_misc is to
> > spawn the
> > +      	    binary lazily when the misc format file is
> > invoked.  However,
> > +	    this doesn't work very well in the face of mount
> > namespaces and
> > +	    changeroots, so the F mode opens the binary as soon as
> > the
> > +	    emulation is installed and uses the opened image to
> > spawn the
> > +	    emulator, meaning it is always available once
> > installed,
> > +	    regardless of how the environment changes.
> >  
> >  
> >  There are some restrictions: