samba - Jun 2024 - libsamba-policy.cpython: where it is used in samba?

On Sat, 2024-05-25 at 14:25 +0300, Michael Tokarev via samba
wrote:
> Hi!
> I'm trying to find where various components of samba belongs to and
> where they're used.There are quite a few files with unknown
> purpose.  For example, a cpython library(python code which is to be
> linked to from a C program) libsamba-policy.  On currentdebian it is
> like:
>    usr/lib/x86_64-linux-gnu/libsamba-policy.cpython-311-x86-64-linux-
> gnu.so.0.0.1   usr/lib/python3/dist-packages/samba/policy.cpython-
> 311-x86_64-linux-gnu.so   usr/lib/x86_64-linux-gnu/pkgconfig/samba-
> policy.cpython-311-x86_64-linux-gnu.pc
> (the libraries are part of python3-samba package, the .pc file is
> part of samba-dev).
> I don't see these are referenced anywhere.  What it is for?
> Also, what it *is* to begin with?  It looks like it is a python code
> embeddableinto a C program, and next it's linked to with a python
> extension?
> Can't the said python extension (samba-policy.cpython) run python
> code inlibsamba-policy directly, without the C/so wrapper?
This is a component used in the samba.policy python lib and also
available as an public library for other software to use (!).
I don't think anybody has considered if this is a wise API to be
exposing since it was added in the pre 4.0 days.  
I also am unclear if 
commit 5324b943e72d597da178d362f7c938fe0a4e57b0Author: Jelmer Vernooij
<jelmer at samba.org>Date:   Mon Oct 11 01:09:26 2010 +0200
    wafsamba: Fix handling of pyembed/pyext.
Is correct here, I think this is a normal Samba library that is called
from python, it doesn't use python things (unlike pyldb-util/pytalloc-
util)
I would put in in the python package, and hopefully we can at least
make it a normal librar and perhaps deprecate it being public soon.
Andrew Bartlett

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26.05.2024 13:13, Andrew Bartlett wrote:
> On Sat, 2024-05-25 at 14:25 +0300, Michael Tokarev via samba wrote:
>> Hi!
>>
>> I'm trying to find where various components of samba belongs to and
where they're used.
>> There are quite a few files with unknown purpose.  For example, a
cpython library
>> (python code which is to be linked to from a C program)
libsamba-policy.  On current
>> debian it is like:
>>
>>    
usr/lib/x86_64-linux-gnu/libsamba-policy.cpython-311-x86-64-linux-gnu.so.0.0.1
>>    
usr/lib/python3/dist-packages/samba/policy.cpython-311-x86_64-linux-gnu.so
>>    
usr/lib/x86_64-linux-gnu/pkgconfig/samba-policy.cpython-311-x86_64-linux-gnu.pc
>>
>> (the libraries are part of python3-samba package, the .pc file is part
of samba-dev).
There's one more case like this, now with a separate package in debian,
python3-ldb-dev:

   usr/include/samba-4.0/pyldb.h
   usr/lib/x86_64-linux-gnu/pkgconfig/pyldb-util.cpython-311-x86_64-linux-gnu.pc
   usr/lib/x86_64-linux-gnu/libpyldb-util.cpython-311-x86-64-linux-gnu.so

and
   usr/lib/x86_64-linux-gnu/libpyldb-util.cpython-311-x86-64-linux-gnu.so.2.6.2
in python3-ldb package.

> This is a component used in the samba.policy python lib and also available
as an public library for other software to use (!).
> 
> I don't think anybody has considered if this is a wise API to be
exposing since it was added in the pre 4.0 days.
I think both of these (samba-policy-cpython C interface and pyldb C interface)
can be dropped.  There's no realistic way to use these libraries from a C
code unless you're deep into python internals - note the names of the .pc
files, they depend on the python internal characteristics.  If they were
named like pyldb-util.pc (or samba-policy.cpython.pc), there'd be a way
to use them, but now now.

I'll drop these in debian first, as a sort of playground.

python-ldb-dev has been added in

commit 36ba3bdb84349660ec7aa9bae9f82e4721aee95a
Author: Jelmer Vernooij <jelmer at debian.org>
Date:   Sat Oct 23 20:52:04 2010 +0200

     * New upstream snapshot.
      + Add python-ldb-dev package.

and not used anywhere.  Maybe it was used when libldb were a separate
package though.


> I also am unclear if
> 
> commit 5324b943e72d597da178d362f7c938fe0a4e57b0
> Author: Jelmer Vernooij <jelmer at samba.org  <mailto:jelmer at
samba.org>>
> Date:   Mon Oct 11 01:09:26 2010 +0200
> 
>      wafsamba: Fix handling of pyembed/pyext.
> 
> Is correct here, I think this is a normal Samba library that is called from
python, it doesn't use python things (unlike pyldb-util/pytalloc-util)
Oh. Also pytalloc-util and python3-talloc-dev, - similar thing to
pyldb-util and python3-ldb-dev.  Also unused.
> I would put in in the python package, and hopefully we can?at least make it
a normal library and perhaps deprecate it being public soon.
Why put these anywhere at all?  These things aren't used already,
as far as I can see - again, if not because it's quite difficult
to use.

Thanks,

/mjt

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