Hi Maher,

My original experience when installing the Perl module XML::LibXSLT on RHEL 8 was that you need to install the CPAN version rather than the packaged (RPM using yum or dnf) version.  However, this was a much earlier version of RHEL 8 (actually it was Rocky Linux 8).  The issue with XML::LibXSLT is that it uses the shared object file /usr/lib64/libxslt.so (which symlinks to a file with a filename that includes the current version) and it seems that certain versions of both this shared object and XML::LibXSLT need to be installed to work with Apache running in MPM event mode to avoid it segfaulting.  Therefore, the instruction to use MPM prefork mode, which is included as advice under the Issues with RHEL / CentOS / Rocky Linux 9 [1] is also the best solution if you have similar problems on RHEL 8.

If you want to run in MPM event mode you can but you will need to not install XML::LibXSLT either as a package or using CPAN.  Looking at some Rocky Linux 8 servers you can still have the libxslt RPM still installed it is just the loading of XML::LibXSLT into Apache that cause the segfault.  The result of not installing XML::LibXSLT is that some XSLT based import plugins will not be available:

Atom XML
OpenXML Bibliography

It is also used on some of the OAI-PMH pages (e.g. /cgi/oai2?verb=ListRecords&metadataPrefix=oai_dc).  However, here I think this is only to visualize XML within a webpage rather than OAI-PMH export harvesting functionality that may be used by third-party applications.  Therefore, you have a choice to leave MPM event enabled for Apache and lose this functionality or enable MPM prefork instead (using the instructions you described) and allow XML::LibXSLT to be installed (best to do this using yum/dnf) so you have this functionality available.

I will look into updating the instructions on the wiki [2] to better explain the situation for RHEL 8.  If I have time, I will do some investigation to see if there is anyway to have XML::LibXSLT installed and still run Apache in MPM event mode.  However, I think you and others have already done exhaustive testing of this.

Regards

David Newman

[1] https://wiki.eprints.org/w/Installing_EPrints_on_RHEL/Fedora/CentOS#Compatibility_issues_with_XML::LibXSLT_2
[2] https://wiki.eprints.org/w/Installing_EPrints_on_RHEL/Fedora/CentOS#Compatibility_issues_with_XML::LibXSLT

CAUTION: This e-mail originated outside the University of Southampton.

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Hi

I just read again the following note mentioned in the documentation and realized that even if perl-XML-LibXSLT is installed using CPAN it also generates an httpd segmentation fault.  So does this mean that we can go ahead and install perl-XML-LibXSLT using dnf and just apply the below fix to resolve the segmentation error?

Kindly confirm.

Compatibility issues with XML::LibXSLT

Installing XML::LibXSLT either through the perl-XML-LibXSLT or through CPAN causes httpd to generate a segmentation fault when you try to start it. The most straightfoarward solution to this is to run httpd in mpm-prefork rather than mpm-event mode. This can be acheived by editing /etc/httpd/conf.modules.d/00-mpm.conf and commenting out the following line:

LoadModule mpm_event_module modules/mod_mpm_event.so

and uncommenting the mpm-prefork line:

LoadModule mpm_prefork_module modules/mod_mpm_prefork.so

Thanks 

Maher

-------- Original message --------

From: Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>

Date: 9/22/23 1:53 PM (GMT+03:00)

To: eprints-tech@ecs.soton.ac.uk

Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. Internal [root@ sftp-gsadmissions-1 ~]# cat /etc/redhat-release Red Hat Enterprise Linux release 8. 6

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Internal

 

[root@sftp-gsadmissions-1 ~]# cat /etc/redhat-release

Red Hat Enterprise Linux release 8.6 (Ootpa)

 

[root@sftp-gsadmissions-1 ~]# hostnamectl

   Static hostname: sftp-gsadmissions-1.test.kfupm.edu.sa

         Icon name: computer-vm

           Chassis: vm

        Machine ID: 8830aac9e8e648238e78e56f6edae34b

           Boot ID: b23e23a3c01443b1a774e86138f6df66

    Virtualization: vmware

  Operating System: Red Hat Enterprise Linux 8.6 (Ootpa)

       CPE OS Name: cpe:/o:redhat:enterprise_linux:8::baseos

            Kernel: Linux 4.18.0-372.9.1.el8.x86_64

      Architecture: x86-64

 

Thanks

Maher

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of Andrew Mehta
Sent: Friday, September 22, 2023 12:45 PM
To: eprints-tech@ecs.soton.ac.uk
Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

Or did I speak too soon? A quick google, and I learn hostnamectl may give more info, and works on any RedHat above version 7, =). From: Andrew Mehta <A. J. Mehta@ soton. ac. uk> Sent: 22 September 2023 10: 42 To: eprints-tech@ ecs. soton. ac. uk

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Or did I speak too soon?

A quick google, and I learn

hostnamectl

may give more info, and works on any RedHat above version 7, =).

 

---

From: Andrew Mehta <A.J.Mehta@soton.ac.uk>
Sent: 22 September 2023 10:42
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

Should you be able to run:

cat /etc/redhat-release

I can be informed of the specific version of your RedHat =).

 

---

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> on behalf of Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>
Sent: 22 September 2023 10:10
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Thank you very much for your support and looking forward to your update.

 

 

 

-------- Original message --------

From: Andrew Mehta <A.J.Mehta@soton.ac.uk>

Date: 9/22/23 11:06 AM (GMT+03:00)

To: eprints-tech@ecs.soton.ac.uk

Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

I believe in doing things properly, so I'll spin up a VM with Redhat 8. 6 at some point today (or more likely this evening as it's looking like a busy day) and try and replicate what you're experiencing here. You had no problem with the dnf

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I believe in doing things properly, so I'll spin up a VM with Redhat 8.6 at some point today (or more likely this evening as it's looking like a busy day) and try and replicate what you're experiencing here.

 

You had no problem with the dnf perl bindings installation,

and only with the cpan installs,

from what I gather.

 

John's mentioning of version numbers reminds me - you can use cpan or cpanm to install specific versions of modules too.

 

If there's a known version that works well with your RedHat 8.6, you could ask cpan or cpanm to specifically install that version.

 

This is assuming I'm not confusing Perl Module versions with underlying lxslt versions.

I once had a problem running Alien::ImageMagick on an older version of CentOS, and found it was attempting to install a version of ImageMagick not compatible with my OS, so I just jumped into the part of the cpan module that specified what version of ImageMagick to install, changed it to a last known working version, and that solved the problem, giving me a uniquely patched version of the cpan module to install to solve my particular issue.

 

Of course in this case, the error we're facing is it not being found. Which means there's a risk it could be there and working and just not being located.

 

Obviously I'm only speculating and could be completely wrong.

 

I'll replace hypothetical guessing with experience and results from trial and error,

when I get the VM going later today.

 

Of course, the problem could be something unique to your setup Maher, that I may not be able to initially replicate with a VM, and might be able to replicate with further communication with you. For now, I'll give it a go later today, and see what I find, then I'll post back here and share any findings.

 

Feel free to experiment with other potential solutions in the meantime.

Or take a break if it's driving you potty ;-).

 

Yours,

Andrew.

 

 

---

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> on behalf of Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>
Sent: 22 September 2023 03:47
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Internal

 

Tried this command

./cpanm -l local https://github.com/shlomif/perl-XML-LibXSLT.git@master

 

But received the same error:

cpanm (App::cpanminus) 1.7047 on perl 5.026003 built for x86_64-linux-thread-multi

Work directory is /root/.cpanm/work/1695350723.167984

You have make /bin/make

You have LWP 6.34

You have /bin/tar: tar (GNU tar) 1.30

Copyright (C) 2017 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.

This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law.

 

Written by John Gilmore and Jay Fenlason.

You have /bin/unzip

Cloning https://github.com/shlomif/perl-XML-LibXSLT.git

Cloning into '/tmp/JDue8C3Kpl'...

Already on 'master'

Your branch is up to date with 'origin/master'.

-> OK

--> Working on https://github.com/shlomif/perl-XML-LibXSLT.git@master

Entering /tmp/JDue8C3Kpl

Configuring /tmp/JDue8C3Kpl

Running Makefile.PL

running pkg-config libxslt... ok

looking for -lxslt... no

libxslt not found

Try setting LIBS and INC values on the command line

Or get libxslt and libxml2 from

  http://www.libxml.org/

If you install via RPMs, make sure you also install the -devel

RPMs, as this is where the headers (.h files) are.

-> N/A

-> FAIL Configure failed for https://github.com/shlomif/perl-XML-LibXSLT.git@master. See /root/.cpanm/work/1695350723.167984/build.log for details.

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of Maher Abdellatif Ahmad Qahwash
Sent: Friday, September 22, 2023 5:36 AM
To: eprints-tech@ecs.soton.ac.uk
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. Internal We received the following error: [root@ sftp-gsadmissions-1 bin]# ./cpanm git: //github. com/shlomif/perl-XML-LibXSLT. git@ master

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Internal

 

We received the following error:

[root@sftp-gsadmissions-1 bin]# ./cpanm git://github.com/shlomif/perl-XML-LibXSLT.git@master

Cloning git://github.com/shlomif/perl-XML-LibXSLT.git ... FAIL

! Failed cloning git repository git://github.com/shlomif/perl-XML-LibXSLT.git

! Couldn't find module or a distribution git://github.com/shlomif/perl-XML-LibXSLT.git@master

 

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of John Salter
Sent: Friday, September 22, 2023 1:09 AM
To: eprints-tech@ecs.soton.ac.uk
Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. I meant you should try to download/install from GitHub, rather than via dnf or the CPAN archive. Newer

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I meant you should try to download/install from GitHub, rather than via dnf or the CPAN archive.

Newer versions of cpanm apparently allow you to do this (I've never tried this before!):

 

> cpanm git://github.com/shlomif/perl-XML-LibXSLT.git@master

 

Does that help at all?

 

I personally haven't tried running EPrints on RHEL8. Others might be able to answer that question.

 

Cheers,

John 

 

---

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> on behalf of Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>
Sent: 21 September 2023 19:59
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Do you mean to download the xml-libxslt 1.96.6 and try to manually install it by running the makefile.pl ....?

 

Would appreciate if you have clear steps to try to resolve this issue.

 

Do you know if eprints has been successfully tested to run on redhat 8.6 or not?

 

-------- Original message --------

From: John Salter <J.Salter@leeds.ac.uk>

Date: 9/21/23 9:28 PM (GMT+03:00)

To: eprints-tech@ecs.soton.ac.uk

Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. There are quite a few changes from 1. 96. 6 (which I think is what RHEL provides from their repo) and

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There are quite a few changes from 1.96.6 (which I think is what RHEL provides from their repo) and 2.001001 (CPAN version).

 

Maybe try cloning the git repo for it, and following their instructions (I can't remember what the process is off the top of my head!).

 

---

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> on behalf of Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>
Sent: 21 September 2023 19:15
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Internal

 

We modified the Makefile.pl file as mentioned in the link, but running the perl Makefile.PL did not work as shown below:

 

[root@sftp-gsadmissions-1 XML-LibXSLT-2.002001]# perl Makefile.PL

running pkg-config libxslt... ok

looking for -lxslt... no

libxslt not found

Try setting LIBS and INC values on the command line

Or get libxslt and libxml2 from

  http://www.libxml.org/

If you install via RPMs, make sure you also install the -devel

RPMs, as this is where the headers (.h files) are.

[root@sftp-gsadmissions-1 XML-LibXSLT-2.002001]# ^C

[root@sftp-gsadmissions-1 XML-LibXSLT-2.002001]# make

make: *** No targets specified and no makefile found.  Stop.

 

Are there any other modification required to be made in the Makefile.PL file? As it is still complaining that libxslt not found??

 

Thanks,

Maher

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of Maher Abdellatif Ahmad Qahwash
Sent: Thursday, September 21, 2023 8:11 PM
To: eprints-tech@ecs.soton.ac.uk
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. Internal Where do I get the Makefile. pl file to modify it? After modifying it should I still use CPANM

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Internal

 

Where do I get the Makefile.pl file to modify it?

 

After modifying it should I still use CPANM to install?

 

Please send the steps f possible.

 

Thanks,

Maher

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of John Salter
Sent: Thursday, September 21, 2023 6:44 PM
To: eprints-tech@ecs.soton.ac.uk
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton. CAUTION: This e-mail originated outside the University of Southampton. Whatever the problem is, it’s not obvious! This might be related: https: //github. com/shlomif/perl-XML-LibXSLT/issues/6

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CAUTION: This e-mail originated outside the University of Southampton.

Whatever the problem is, it’s not obvious!

 

This might be related:

https://github.com/shlomif/perl-XML-LibXSLT/issues/6

 

Does this update to the Makefile.pl help:
https://github.com/shlomif/perl-XML-LibXSLT/commit/45edf81581d6ef4e9a269feda31c5f57633ac0d9

 

It doesn’t look like the above commit has made it to a release version yet – but I’m not sure why that would cause the CPAN route to fail, unless the CPAN and DNF are different version numbers…

 

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of Maher Abdellatif Ahmad Qahwash
Sent: Thursday, September 21, 2023 3:42 PM
To: eprints-tech@ecs.soton.ac.uk
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Internal

 

We are not sure if installing the perl-XML-LibXSLT using dnf will cause any segmentation faults with our Apache httpd webserver or not.  We are just following the recommendation in the documentation to install using CPAN.

 

Following is the cpanm –V output:

 

# ./cpanm -V

cpanm (App::cpanminus) version 1.7047 (./cpanm)

perl version 5.026003 (/usr/bin/perl)

 

  %Config:

    archname=x86_64-linux-thread-multi

    installsitelib=/usr/local/share/perl5

    installsitebin=/usr/local/bin

    installman1dir=/usr/share/man/man1

    installman3dir=/usr/share/man/man3

    sitearchexp=/usr/local/lib64/perl5

    sitelibexp=/usr/local/share/perl5

    vendorarch=/usr/lib64/perl5/vendor_perl

    vendorlibexp=/usr/share/perl5/vendor_perl

    archlibexp=/usr/lib64/perl5

    privlibexp=/usr/share/perl5

  %ENV:

  @INC:

    FatPacked::94715887577112=HASH(0x5624c2d56818)

    /usr/local/lib64/perl5

    /usr/local/share/perl5

    /usr/lib64/perl5/vendor_perl

    /usr/share/perl5/vendor_perl

    /usr/lib64/perl5

    /usr/share/perl5

 

 

This is the content of the file “XML-LibXSLT-2.002001-0.yml”

---

distribution: !!perl/hash:CPAN::Distribution

  CALLED_FOR: XML::LibXSLT

  CHECKSUM_STATUS: OK

  ID: S/SH/SHLOMIF/XML-LibXSLT-2.002001.tar.gz

  RO:

    CPAN_COMMENT: ~

    CPAN_USERID: SHLOMIF

  archived: tar

  build_dir: /root/.local/share/.cpan/build/XML-LibXSLT-2.002001-0

  incommandcolor: 1

  localfile: /root/.local/share/.cpan/sources/authors/id/S/SH/SHLOMIF/XML-LibXSLT-2.002001.tar.gz

  mandatory: 1

  negative_prefs_cache: 1

  prefs: {}

  reqtype: c

  unwrapped: !!perl/hash:CPAN::Distrostatus

    COMMANDID: 1

    FAILED: ''

    TEXT: YES

    TIME: 1695294479

  writemakefile: !!perl/hash:CPAN::Distrostatus

    COMMANDID: 1

    FAILED: 1

    TEXT: "NO -- No 'Makefile' created\n"

    TIME: 1695294480

perl:

  $^X: /usr/bin/perl

  mtime_$^X: 1673971108

  mtime_dll: 0

  sitearchexp: /usr/local/lib64/perl5

time: 1695294480

 

Thank you for your support.

Maher

 

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> On Behalf Of Andrew Mehta
Sent: Thursday, September 21, 2023 5:31 PM
To: eprints-tech@ecs.soton.ac.uk
Subject: Re: [EP-tech] Migrating to Redhat Linux 8.6

 

Is it a problem for your EPrints migration if perl-XML-LibXSLT is working fine for you? The CPAN install idea is only if you sometimes find the perl-XML-LibXSLT package causes segmentation faults with the Apache httpd webserver. You mention

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Is it a problem for your EPrints migration if
perl-XML-LibXSLT
is working fine for you?

 

The CPAN install idea is only if you sometimes find the perl-XML-LibXSLT package causes segmentation faults with the Apache httpd webserver.

You mention you are using cpanm.
Is the following command...

cpanm -V 

...showing the correct installation locations?

 

Is any further info in build logs in your user's home directory's ".cpanm" folder?

 

---

From: eprints-tech-request@ecs.soton.ac.uk <eprints-tech-request@ecs.soton.ac.uk> on behalf of Maher Abdellatif Ahmad Qahwash <qahwash@kfupm.edu.sa>
Sent: 21 September 2023 15:20
To: eprints-tech@ecs.soton.ac.uk <eprints-tech@ecs.soton.ac.uk>
Subject: RE: [EP-tech] Migrating to Redhat Linux 8.6

 

CAUTION: This e-mail originated outside the University of Southampton.

CAUTION: This e-mail originated outside the University of Southampton.

Internal

 

Sorry the libxslt is a folder (not a file) and is located here:

/usr/include/libxslt

 

We also have the following libxslt files here:

/usr/lib64/libxslt.so.1.1.32

/usr/lib64/libxslt-plugins

/usr/lib64/libxslt.so.1

/usr/lib64/pkgconfig/libxslt.pc

/usr/lib64/libxslt.so

/usr/share/licenses/libxslt

 

 

The error appearing when trying to install using CPAN is this:

looking for -lxslt... no

libxslt not found

 

 

From: <a class="moz-txt-link

...

...