[cap-talk] POLA? Unix FDs as capabilities? Plash future + YURLs?

[David Mercer]

On 11/19/05, Tyler Close <tyler.close at gmail.com> wrote:
> On 11/17/05, Jed at Webstart <donnelley1 at webstart.com> wrote:
> > At 04:19 PM 11/17/2005, Toby Murray wrote:
> > >Jed at Webstart wrote:
> > >>On the other hand, perhaps Tyler's YURLs and the Web can serve for
> > >>the permanent management of resource access?  Then if Plash could
> > >>communicate "capabilities" to processes as open file descriptors
> > >>that represent pipes to a local server that accesses the
> > >>corresponding resources through YURLs ...  Well, that is getting
> > >>ahead of the game, but I could imagine it.  Quite a hack and
> > >>probably unworkable, but close to satisfying the basic needs.
> > >
> > >This is quite interesting. I'm imagining (from your description)
> > >YURLs as a sort of "universal" capability representation that is
> > >machine independent (like E's sturdyref's I suppose), where on the
> > >Unix implementation we use file descriptors to represent them
> > >locally. YURLs are "resolved" to local file descriptors, like E
> > >sturdyrefs are "resolved" to object references. (please excuse me if
> > >I've got the terminology wrong here, I'm no E hacker).
>
> As Jed wrote, I once implemented something very similar to this.
> Instead of binding a YURL to a file descriptor, I bound a YURL to an
> operation on a file descriptor. A single file therefore had a set of
> YURLs bound to it, one for each exported operation. For example, there
> was a YURL to fetch the current file contents, another to overwrite
> the file and another to delete the file. There was a similar schema
> for directory operations. The resulting application was quite useful
> for remote file management through a web browser; however, people
> mostly used it as a crude form of wiki. This lead me to build a less
> crude wiki that you can find at <https://yurl.net/>. Reviving the file
> management application might be fun and useful.
>
> I never built the reverse mapping of turning operations on file
> descriptors into HTTP requests on YURLs, though I lusted for it. Such
> a mapping would enable use of vim for remote file management, which
> may be preferable to the web browser for many tasks.

Such a thing, lashed together properly with plash, could indeed be a good start
with bringing networked pola capabilities to posix (or at least
linux!), I would think.
Object/vat locator services hacked onto the dns for host location, as
we've betted around on this list, could start bootstrapping the whole
thing partially off of the dns and pki infrastructure that's bound up
with IPv4.  A VLS/ODNS server shouldn't care what IP version the host
that serves locations for an object lives at (note that I'm implying a
layer of indirection beyond a VLS telling clients what host has an
object).
And only the hash of the server that provides names for an object is
ever potentially sent in the clear, and that need only ever happen in
the IPv4 case.

Polarias or a similar open source tool on Windows could take the place
of Plash/it's X-Windows embodiment on that platform.  Getting
closer....

-David Mercer
Tucson, AZ