CVS update: tng/source/passdb
Luke Kenneth Casson Leighton
lkcl at samba-tng.org
Tue Jan 8 02:22:08 GMT 2002
On Tue, Jan 08, 2002 at 01:33:17PM +1100, Martin Pool wrote:
> On 8 Jan 2002, Luke Kenneth Casson Leighton <lkcl at samba-tng.org> wrote:
> > > well, if head is running then the packets will be going via smbd
> > > code. No choice about that.
> > that's not the issue.
> > how can an ARBITRARY dce/rpc-based program - NOT a .so - one
> > that is UTTERLY INDEPENDENT of samba, run and register
> > itself?
> Perhaps making this concrete might help, though I'm not sure if this
> is the example Luke has in mind:
> Somebody might plausibly want to make GNOME Evolution talk to Exchange
> over rpc,
yes. in fact, this has been on the wishlist since 1996, iirc correctly.
> or conversely implement a Unix Exchange replacement.
> Especially if they were free, Samba developers would probably think
> they are good things, and certainly many Samba users would like to use
> It seems to me that Luke is arguing that authors of these programs
> would like to avoid writing their own dcerpc implemnetation, because
> it is a large project.
250,000 lines of code and up. anyone wishing to do their own
dce/rpc implementation i now deem to be utterly mad. including
> On the other hand, they can't use Samba's code
> at the moment because it is too tied to the rest of the program. One
> example of this is that practically everything depends on loadparm.c.
that is absolutely correct.
> It might be nice if the code to do dcerpc was less coupled to Samba,
> so that it can be reused to help such good causes. So Evolution can
> link to libsambadce or whatever, and share code maintenance. (In
> fact, it looks like it would probably be a library plus code
> generator, like most RPC systems.)
> Once you've made that split, you could perhaps refactor Samba to use
> the library from several different processes. That seems like a
> secondary point, and simply a matter of taste for Samba developers.
> I don't know the code nearly well enough to say whether it could be
> done, and certainly refactoring Samba for the benefit of other
> projects (which don't apparently exist yet) is a lot to ask.
> Potential downsides are numerous:
> - The library needs to have a stable interface, which limits our
> ability to evolve it.
it's quite simple, in fact. i've been thinking about this interface
for several months over the last three to four years, so we
stand a good chance of getting it right first time.
if not, versioning / support (like 2-stage SMB CAPABILITIES
negotiation) could be added, which makes it a future-proof interface.
> Also to be useful it must be more thoroughly
> documented than an internal interface, which will take effort.
> - For various reasons (licensing, control, threading, ...), other
> projects might choose not to use this library anyhow, so the work
> of separating it would be wasted.
not true. the publication and release as an rfc of an IDL file
as the specification would allow both the client-side
and server-side implementation
of the parser needed to be generated in seconds, on modern
platforms, using freedce or any other dce/rpc IDL compiler
> - Clean interfaces are sometimes slower than tightly coupled ones.
> Since some silly people do care about benchmarks this might be a
> - It might not be possible to write a clean interface to dcerpc,
> because of cross-layer coupling - e.g. authentication carried out
> at different levels of the stack, etc.
that's implementation specific.
> I'm having a look at NDR DCE/RPC code generation at the moment, and
> will try to keep whatever I write reasonably modular. Whether anybody
> will actually use it I don't know.
it's in the idllib/ directory.
talk to wez furlong, he's familiar with the code.
btw, i should point out that if an IDL file is used, then
you can either:
- hand-code it like i did [mad!!!]
- use aparser the awk auto-generator that andrew developedd
- use freedce's dceidl compiler.
- even use MIDL.EXE!
any of these approaches is perfectly acceptable and valid.
and now i _have_ to go: some people are depending on me
in cambridge for materials and i was up late last night
i lose money and time dealing with this stuff if those
people stand around on their thumbs or worse, go out to
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