For the next release, I'd like to implement permissions for procedural
languages.  It would be one permission called USAGE, which allows the user
to create a function using that language.  I will reuse the aclitem[]
approach, in the same way as I'm already doing for functions.

The first consequence is that we could get rid of createlang as the
primary means of access control to languages.  I would like to install all
languages by default (excluding only those that haven't been included by
"configure").  Would people be afraid if we made the trusted languages
available to all users by default?  That would really be a lot more
convenient.

The "trusted" flag could be done away with.  However, the current
untrusted languages (pltclu and plperlu) actually use the trusted flag
both as an external access control and internally to decide how to behave.
We could keep the latter use for now, until perhaps someone invents a
generic language configuration mechanism.

Furthermore, we can conveniently eliminate the problems related to finding
all the language handlers as shared libraries.  Since all languages are
installed by default we can just link the handlers right into the
postmaster, for which we don't need shared libraries.  That should give a
great boost to languages that are currently hard to build, i.e., PL/Perl
and PL/Python.  And the build system would become a lot simpler and more
portable.

Any comments on these points?

-- 
Peter Eisentraut   peter_e@gmx.net


Tue, 15 Jan 2002 22:09:17 -0500 (EST)
Peter Eisentraut <peter_e@gmx.net>
Procedural language permissions and consequences
Peter Eisentraut <peter_e@gmx.net> writes:

> Furthermore, we can conveniently eliminate the problems related to finding
> all the language handlers as shared libraries.  Since all languages are
> installed by default we can just link the handlers right into the
> postmaster, for which we don't need shared libraries.  That should give a
> great boost to languages that are currently hard to build, i.e., PL/Perl
> and PL/Python.  And the build system would become a lot simpler and more
> portable.
> 
> Any comments on these points?

Just that I imagine it's quite useful, while hacking on a procedural
language, to be able to restart the postmaster and reload the library,
rather than relinking and reinstalling the postmaster binary.  So
keeping the option for PLs in shared libraries is probably a good
idea, though having the "standard" ones compiled in makes some sense.

Wouldn't a postmaster statically linked with libperl.a and libpyhon.a
be pretty big?  Would that cause problems?

-Doug
-- 
Let us cross over the river, and rest under the shade of the trees.
   --T. J. Jackson, 1863

15 Jan 2002 22:36:57 -0500
Doug McNaught <doug@wireboard.com>
Re: Procedural language permissions and consequences
Peter Eisentraut <peter_e@gmx.net> writes:
> The first consequence is that we could get rid of createlang as the
> primary means of access control to languages.  I would like to install all
> languages by default (excluding only those that haven't been included by
> "configure").  Would people be afraid if we made the trusted languages
> available to all users by default?

The arguments against this seem pretty thin on review.  I would like to
be able to remove a language I don't want --- but I have no objection
to reversing the default.

> Furthermore, we can conveniently eliminate the problems related to finding
> all the language handlers as shared libraries.  Since all languages are
> installed by default we can just link the handlers right into the
> postmaster, for which we don't need shared libraries.  That should give a
> great boost to languages that are currently hard to build, i.e., PL/Perl
> and PL/Python.  And the build system would become a lot simpler and more
> portable.

This I do *not* like.  plpgsql is the single thing keeping us honest
on portability of shlib extensions.  If the default and only tested
behavior is for statically-linked PL extensions, you can be sure that
dynamically-linked extensions will be suffering bit rot very soon.

And I do not see it as our problem that perl and python make life
unnecessarily difficult for those who would include them as libraries.
Tcl showed the way years ago; it's past time for those guys to see the
light, if they'd like to be adopted more widely.

See also Doug's points, nearby.

			regards, tom lane

Wed, 16 Jan 2002 00:37:46 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: Procedural language permissions and consequences 
[Hi all! Time for an introduction: I'm just a postgresql user with an
interest for the theory behind it (cs student), so I've started to read
hackers a while back. As the most frequent reason for me being annoyed
about Linux is the Packaging system I just wanted to throw this in
here:]

On Wed, 2002-01-16 at 04:09, Peter Eisentraut wrote:

> Furthermore, we can conveniently eliminate the problems related to finding
> all the language handlers as shared libraries.  Since all languages are
> installed by default we can just link the handlers right into the
> postmaster, for which we don't need shared libraries.  That should give a
> great boost to languages that are currently hard to build, i.e., PL/Perl
> and PL/Python.  And the build system would become a lot simpler and more
> portable.

A reason against this not addressed by the others: Doing the languages
as shared libraries opened only at runtime enables for more easy
packaging - psotgresql core pkg with optional psql-tcl, psql-perl,...
packages. Linking the libraries in requires packagers to do postgresql,
postgresql-perl, postgresql-tcl, postgresql-perl+tcl etc. packages.

(I don't know exactly if packagers currently use this possibility. It's
been a while since I last installed postgres)

Greets
-- vbi



16 Jan 2002 09:26:18 +0100
"Adrian 'Dagurashibanipal' von Bidder" <avbidder@fortytwo.ch>
Re: Procedural language permissions and consequences
Doug McNaught writes:

> Just that I imagine it's quite useful, while hacking on a procedural
> language, to be able to restart the postmaster and reload the library,
> rather than relinking and reinstalling the postmaster binary.  So
> keeping the option for PLs in shared libraries is probably a good
> idea, though having the "standard" ones compiled in makes some sense.

PLs work just like user-defined C functions, so the possibility to load
your own is not going anywhere.

> Wouldn't a postmaster statically linked with libperl.a and libpyhon.a
> be pretty big?  Would that cause problems?

I wouldn't think so.  First, if you link statically you only get the code
you actually use (more or less).  Second, even if you get most of it, code
is only loaded into memory if you actually use it.  Third, if you don't
like it you should provide the appropriate shared libraries and the linker
should use them automatically.

-- 
Peter Eisentraut   peter_e@gmx.net


Wed, 16 Jan 2002 11:23:42 -0500 (EST)
Peter Eisentraut <peter_e@gmx.net>
Re: Procedural language permissions and consequences
Tom Lane writes:

> This I do *not* like.  plpgsql is the single thing keeping us honest
> on portability of shlib extensions.

That is not correct.  The regression tests load and use all kinds of other
shared library extensions.

I certainly don't like the notion you suggest that we should create or
keep arbitrary detours in the common usage path just to prove that those
detours still work.  That is what test suites are for, and I'd be happy to
provide more tests if what we currently have doesn't satisfy you
(including a dummy dynamically loaded language handler?).

I could see a build-time option to determine in which way the PL handlers
are linked, but I really don't buy this argument.

> And I do not see it as our problem that perl and python make life
> unnecessarily difficult for those who would include them as libraries.

In a sense it is our problem, because we are providing features that are
based on interfaces that don't officially exist, and we are making life
more difficult for users that way.  Years of Apache/mod_perl didn't
convince anybody to provide a shared libperl, so what makes you think
someone is going to start on our say-so?

-- 
Peter Eisentraut   peter_e@gmx.net


Wed, 16 Jan 2002 11:41:39 -0500 (EST)
Peter Eisentraut <peter_e@gmx.net>
Re: Procedural language permissions and consequences 