Re: feature-mtab-translator (v3)

[Neal H. Walfield]

At Mon, 22 Jul 2013 22:49:03 +0200,
Samuel Thibault wrote:
> 
> Neal H. Walfield, le Mon 22 Jul 2013 21:50:02 +0200, a écrit :
> > At Fri, 19 Jul 2013 17:25:02 +0200,
> > Justus Winter wrote:
> > > * The translator used to traverse the translator tree and if it
> > >   encountered itself, it would deadlock. This is cleanly solved by
> > >   comparing the control ports of the current node and the mtab
> > >   translator.
> > 
> > I don't think you can reliably do this.  This assumes that the same
> > port is always used for accessing the the fsys facet, which is not
> > necessarily the case.
> 
> What other port could it be?

Perhaps I don't completely understand the situation.

Here's what I'm thinking: if a program somehow fetches an fsys port,
there is no guarantee that the returned send right corresponds to a
unique port (even if this is currently the de facto case).  Consider
opening a file: the port identifies the peropen; every open results in
a new receive right.  Or, consider proxing.  If this is somehow
guaranteed not to be the case here, then I guess a numeric comparison
is acceptable.

Neal