[python-ldap] Solaris, Python-LDAP, Apache: SEGFAULT due to shared library mismatch?

[Chris Dukes]

Steffen,

I had similar headaches with Apache and python-ldap and Django and AIX.
In the end I tossed mod_wsgi for apache and went with one of the fastcgi 
modules and the python pieces as a separate daemon.
Our load was fairly low, so the fastcgi daemon capability that ships 
with Django was enough.  If load had been higher I'd have gone with 
greenunicorn and moved the python bits to Linux.

On 08/29/2013 01:36 PM, Steffen Moser wrote:
> Hi all,
>
> I've got a problem with Python-LDAP on our Solaris 11 based work-
> group and storage server which is mainly used to host a bunch of
> web applications (based on PHP and Python).
>
> Let me recap the basic data:
>
>   - Solaris 11.1 (x86_64)
>
>   - Apache/2.2.24 (Unix) DAV/2 mod_wsgi/3.3 Python/2.6.8
>     mod_ssl/2.2.24 OpenSSL/1.0.0k
>
>   - Python-LDAP 2.4.13 (self-compiled and linked against OpenLDAP
>     2.4.30)
>
> Compilation and installation of Python-LDAP worked well, but as soon
> as a Python script actually uses the LDAP connection, the web server
> worker process dies with a "Segmentation Fault".
>
> When I deactivate the Apache module "mod_ldap.so", the problem is
> gone and Python-LDAP seems to run quite fine, but the thing is: The
> Apache web server also hosts applications which actually need
> "mod_ldap.so" and PHP, so I can't go for that solution.
>
> I suppose that I've found the cause for the problem. While everything
> which is related to Apache (the Apache modules, PHP, and so on), comes
> with Oracle Solaris and needs LDAP is linked to Oracle's own LDAP
> library "/usr/lib/libldap.so.5".
>
> This is, for example, the case for Apache's "mod_ldap.so":
>
>   | smoser at regulus:~# ldd /usr/apache2/2.2/libexec/mod_ldap.so
>   |         libldap.so.5 =>  /usr/lib/libldap.so.5
>   |         libc.so.1 =>     /lib/libc.so.1
>   |         libsasl.so.1 =>  /usr/lib/libsasl.so.1
>   |         libsocket.so.1 =>        /lib/libsocket.so.1
>   |         libnsl.so.1 =>   /lib/libnsl.so.1
>   |         libmd.so.1 =>    /lib/libmd.so.1
>   |         libnspr4.so =>   /usr/lib/mps/libnspr4.so
>   |         libplc4.so =>    /usr/lib/mps/libplc4.so
>   |         libnss3.so =>    /usr/lib/mps/libnss3.so
>   |         libssl3.so =>    /usr/lib/mps/libssl3.so
>   |         libmp.so.2 =>    /lib/libmp.so.2
>   |         libsoftcrypto.so.1 =>    /lib/libsoftcrypto.so.1
>   |         libelf.so.1 =>   /lib/libelf.so.1
>   |         libpthread.so.1 =>       /lib/libpthread.so.1
>   |         librt.so.1 =>    /lib/librt.so.1
>   |         libdl.so.1 =>    /lib/libdl.so.1
>   |         libnssutil3.so =>        /usr/lib/mps/libnssutil3.so
>   |         libplds4.so =>   /usr/lib/mps/libplds4.so
>   |         libthread.so.1 =>        /lib/libthread.so.1
>   |         libcryptoutil.so.1 =>    /lib/libcryptoutil.so.1
>   |         libm.so.2 =>     /lib/libm.so.2
>
>
> Python-LDAP is depending on OpenLDAP, so I can't link it against
> Sun's LDAP libraries (as stated in the FAQs of Python-LDAP):
>
>   | smoser at regulus:~# ldd /usr/lib/python2.6/site-packages/python_ldap-2.4.13-py2.6-solaris-2.11-i86pc.egg/_ldap.so
>   |         libldap-2.4.so.2 =>      /usr/lib/libldap-2.4.so.2
>   |         liblber-2.4.so.2 =>      /usr/lib/liblber-2.4.so.2
>   |         libsasl.so.1 =>  /usr/lib/libsasl.so.1
>   |         libssl.so.1.0.0 =>       /lib/libssl.so.1.0.0
>   |         libcrypto.so.1.0.0 =>    /lib/libcrypto.so.1.0.0
>   |         libpython2.6.so.1.0 =>   /usr/lib/libpython2.6.so.1.0
>   |         libresolv.so.2 =>        /lib/libresolv.so.2
>   |         libnsl.so.1 =>   /lib/libnsl.so.1
>   |         libsocket.so.1 =>        /lib/libsocket.so.1
>   |         libc.so.1 =>     /lib/libc.so.1
>   |         libmd.so.1 =>    /lib/libmd.so.1
>   |         libdl.so.1 =>    /lib/libdl.so.1
>   |         libm.so.2 =>     /lib/libm.so.2
>   |         libmp.so.2 =>    /lib/libmp.so.2
>   |         libsoftcrypto.so.1 =>    /lib/libsoftcrypto.so.1
>   |         libelf.so.1 =>   /lib/libelf.so.1
>   |         libcryptoutil.so.1 =>    /lib/libcryptoutil.so.1
>
>
> So my questions are:
>
>   - Can anybody confirm that this is really the probable cause for the
> problem that we've encountered?
>
>   - Is there any way to get both LDAP libraries to work in one
> instance of apache?
>
>   - Can I link the OpenLDAP libs statically or won't that help?
>
>   - I am not an expert in linking programs in Solaris, but is it
> possible to have the OpenLDAP libraries linked to a separate
> namespace so that they don't interfere in Apache?
>
>
> As far as I know, my options will be:
>
>   - Re-compile Apache and everything that depends on it by linking
> all the LDAP related things to OpenLDAP libs.
>
>   - Run two instances of Apache on two different ports: One for the
> PHP applications and one for the Python applications. The one for
> Python applications must not load any module that is linked against
> Oracle's LDAP lib while the one for the other applications must not
> load any module that is linked against OpenLDAP lib.
>
>   - Modify Python-LDAP that it can be linked against Oracle's LDAP
> library (I assume that this is really a _lot_ of work).
>
>   - Are there any other options that I might have missed?
>
>
> I would be very glad if someone could help me. Thank you very much
> in advance!
>
> Kind regards,
> Steffen
> _______________________________________________
> python-ldap mailing list
> python-ldap at python.org
> http://mail.python.org/mailman/listinfo/python-ldap