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<div class="moz-cite-prefix">Richard,<br>
<br>
I wrote my previous email in two different time-frames, and it
seems that I didn't "link" my two parts correctly, so I'll have to
clarify the following:<br>
<br>
In the first part of my email I'm telling you to install apache
from sources. In the second part though, I'm telling you to try an
alternate way of starting apache which might work as a workaround.
So, if you test the second part and it works, you won't have to
apache from sources. You just have to tell us it worked and we'll
try to see how to preload a library when apache starts in Ubuntu.<br>
<br>
I hope I've made my self clearer this time...:)<br>
<br>
PS. The path of the library used in the command starting with
LD_PRELOAD should be the one that you found when you ran "ldd
/usr/lib/apache2/modules/mod_perl.so | grep -i expat" in your
machine<br>
<br>
On 25/09/2015 03:26 μμ, George Mamalakis wrote:<br>
</div>
<blockquote
cite="mid:EMEW3|749bc9f28ca3f7b3bfed33e0f5f3d209r8ODR114eprints-tech-bounces|ecs.soton.ac.uk|56053D60.3050802@eng.auth.gr"
type="cite">
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<div class="moz-cite-prefix">Hmm, OK,<br>
<br>
I read the site behind the link a bit more carefully and it
seems that this is your problem indeed. You can verify it by
checking the apache2 and mod_perl binaries and see if they're
both linked with expat. Eg, run:<br>
<br>
# ldd /usr/bin/apache2 | grep -i expat<br>
# ldd /usr/lib/apache2/modules/mod_perl.so | grep -i expat<br>
<br>
and you should only see only one of them returning a link with
the expat library. If both return it, then it seems that this is
your case indeed.<br>
<br>
In that case, you'll have to build apache from source if you
want to collocate apache and XML::Parser for perl. There's this
guide for building apache2.4 for Ubuntu (!!<b>not</b> 2.2!!),
but from what I see all apache dependencies are installed (as it
says) from apache2 package, so there might be a problem with
linking to libexpat as well (<a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="http://phpboyscout.uk/compiling-apache-2-4-ubuntu-12-04/">http://phpboyscout.uk/compiling-apache-2-4-ubuntu-12-04/</a>).
On the other hand, linking is mainly performed based on what the
configure script instructs, so at that point you should probably
remove some of it's flags that cause this linkage, but I'm not
sure which. But I'm not sure where the problem comes from:
should apache be built without expat support or mod_perl?
Because this is not clear from the wiki<br>
<br>
I've done a small research with problems related to apache and
lib-expat and in another situation (which seems very similar)
that involved apache and mod_wsgi the problem was that the two
installed expat libraries had different versions that caused
apache to crash (because it was calling some library function
with a different prototype, most probably). You can check each
expat version by running something like:<br>
<br>
# strings /path/to/your/libexpat/binary | grep expat_ <br>
<br>
and you'll most probably find out that the versions differ. The
solution would be for both binaries to use the same expat
library, which theoretically can be achieved by LD_PRELOAD, so
maybe you could start the apache binary from command line using
something like:<br>
<br>
# LD_PRELOAD=/path/to/mod_perls/expat/library
/usr/sbin/apachectl start<br>
<br>
In that case it may work...but this means that you cannot start
or stop apache using Ubuntu's startup scripts, except if Ubuntu
has a way of telling which libraries should be preloaded before
executing the apache binary (which is way out of my knowledge,
since I'm mostly a BSD guy).<br>
<br>
I'm not sure if I helped...:)<br>
<br>
On 25/09/2015 02:07 μμ, George Mamalakis wrote:<br>
</div>
<blockquote
cite="mid:EMEW3|92098043b6574f30c354ea0cb3c82841r8OC8814eprints-tech-bounces|ecs.soton.ac.uk|56052AE0.9060006@eng.auth.gr"
type="cite">
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<div class="moz-cite-prefix">OK,<br>
<br>
First of all try to remove the two plugins one at a time and
in the meantime start apache to see which one breaks apache.<br>
<br>
Building apache from sources is not very dramatic, you just
have to find an "easy guide". I'll search later to see if I
find any and I will come back with the link. Do you run any
other sites through the same apache (which may use PHP, python
or any other server side language)?<br>
<br>
In order to check a binary's linked libraries you can do so
using the ldd command followed by the full path of the binary.
In my system (Debian), running ldd on the apache2 binary
returns:<br>
<br>
# ldd /usr/sbin/apache2<br>
. linux-vdso.so.1 (0x00007fff8bce5000)<br>
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3
(0x00007f6c588ad000)<br>
libaprutil-1.so.0 =>
/usr/lib/x86_64-linux-gnu/libaprutil-1.so.0
(0x00007f6c58684000)<br>
libapr-1.so.0 =>
/usr/lib/x86_64-linux-gnu/libapr-1.so.0 (0x00007f6c5844e000)<br>
libpthread.so.0 =>
/lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f6c58231000)<br>
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6
(0x00007f6c57e88000)<br>
libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1
(0x00007f6c57c82000)<br>
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1
(0x00007f6c57a7a000)<br>
libcrypt.so.1 => /lib/x86_64-linux-gnu/libcrypt.so.1
(0x00007f6c57843000)<br>
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2
(0x00007f6c5763e000)<br>
libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1
(0x00007f6c57415000)<br>
/lib64/ld-linux-x86-64.so.2 (0x00007f6c58dc9000)<br>
<br>
Moreover, to see how many versions of a library are installed
in your system you can use ldconfig with the -p option. So for
example in the same system:<br>
# ldconfig -p | grep -i expat<br>
libexpatw.so.1 (libc6,x86-64) =>
/usr/lib/x86_64-linux-gnu/libexpatw.so.1<br>
libexpatw.so (libc6,x86-64) =>
/usr/lib/x86_64-linux-gnu/libexpatw.so<br>
libexpat.so.1 (libc6,x86-64) =>
/lib/x86_64-linux-gnu/libexpat.so.1<br>
libexpat.so (libc6,x86-64) =>
/usr/lib/x86_64-linux-gnu/libexpat.so<br>
<br>
Using dpkg-query in a debian-based system (like Ubuntu), you
can see which file is installed by which package, so in my
system again:<br>
<br>
# dpkg-query -S /usr/lib/x86_64-linux-gnu/libexpatw.so<br>
libexpat1-dev:amd64: /usr/lib/x86_64-linux-gnu/libexpatw.so<br>
<br>
I see that libexpat1-dev package installed the library of
libexpatw in it.<br>
<br>
Maybe you can use these commands in your system to see what's
wrong.<br>
<br>
On 25/09/2015 01:01 μμ, Richard Jones wrote:<br>
</div>
<blockquote
cite="mid:EMEW3|7b3d7c76fca8fde575faa848a9b2cbacr8OB2Y14eprints-tech-bounces|ecs.soton.ac.uk|CAJaHgurVYMDKLWsSHm2yj=q4_eyuqphabXnZLs03ojwbMKtEbg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div>Hi George,</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div> <br>
It would be good if you could provide the relevant
apache logs. Moreover, if you uninstall the
packages you mentioned you installed yesterday,
does apache work OK?</div>
</div>
</blockquote>
<div><br>
</div>
<div>I haven't tried yet, but I would expect so - it
broke the instant I installed them! I may back them
out to confirm, but I need them installed for the XSLT
import plugins to work.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div> In the link you provided it's talking about
the expat library and I'm not sure the packages
you've mentioned are related to that. </div>
</div>
</blockquote>
<div><br>
</div>
<div>I'm not totally clear either, but they're both XML
related, so seemed like a reasonable bet.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Nonetheless, what the link implies as a
solution (<b>IF</b> this is your problem), is to
install apache through sources so as to remove the
double-linking with lib-expat. </div>
</div>
</blockquote>
<div><br>
</div>
<div>Hm, that's what I was afraid of :) I'm not sure
how to do that, or what it means to "remove the
double-linking", so I'm hesitant to go down that route
just yet.</div>
<div><br>
</div>
<div>Cheers,</div>
<div><br>
</div>
<div>Richard</div>
<div><br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div> <br>
<br>
George.
<div>
<div class="h5"><br>
<br>
On 25/09/2015 12:03 μμ, Richard Jones wrote:<br>
</div>
</div>
</div>
<blockquote type="cite">
<div>
<div class="h5">
<div dir="ltr">
<div>Hi Folks,</div>
<div><br>
</div>
<div>I think that I'm experiencing this
error:</div>
<div><br>
</div>
<a moz-do-not-send="true"
href="http://wiki.eprints.org/w/Troubleshooting#Apache_Crashes_with_a_segmentation_fault"
target="_blank">http://wiki.eprints.org/w/Troubleshooting#Apache_Crashes_with_a_segmentation_fault</a><br
clear="all">
<div><br>
</div>
<div>Yesterday I installed
libxml-libxml-perl and libxml-libxslt-perl
to fix a problem with XSLT crosswalks not
being loaded, and now I'm unable to
restart apache.</div>
<div><br>
</div>
<div>I installed apache2 on my ubuntu system
via the aptitude (so, not from source),
and I installed eprints from source and
manually installed the dependencies via
aptitude.</div>
<div><br>
</div>
<div>The troubleshooting guide tells me what
the problem might be, but doesn't have a
fix - does anyone know how to resolve?</div>
<div><br>
</div>
<div>Cheers,</div>
<div><br>
</div>
<div>Richard</div>
<div><br>
</div>
-- <br>
<div>
<div><br>
</div>
Richard Jones,
<div><br>
</div>
<div>Founder, Cottage Labs
<div>t: @richard_d_jones, @cottagelabs</div>
<div>w: <a moz-do-not-send="true"
href="http://cottagelabs.com"
target="_blank">http://cottagelabs.com</a><br>
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<br>
<pre cols="72">--
George Mamalakis
IT and Security Officer,
Electrical and Computer Engineer (Aristotle Univ. of Thessaloniki),
PhD (Aristotle Univ. of Thessaloniki),
MSc (Imperial College of London)
School of Electrical and Computer Engineering
Aristotle University of Thessaloniki
phone number : +30 (2310) 994379
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-- <br>
<div class="gmail_signature">
<div><br>
</div>
Richard Jones,
<div><br>
</div>
<div>Founder, Cottage Labs
<div>t: @richard_d_jones, @cottagelabs</div>
<div>w: <a moz-do-not-send="true"
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<pre class="moz-signature" cols="72">--
George Mamalakis
IT and Security Officer,
Electrical and Computer Engineer (Aristotle Univ. of Thessaloniki),
PhD (Aristotle Univ. of Thessaloniki),
MSc (Imperial College of London)
School of Electrical and Computer Engineering
Aristotle University of Thessaloniki
phone number : +30 (2310) 994379
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<br>
<pre class="moz-signature" cols="72">--
George Mamalakis
IT and Security Officer,
Electrical and Computer Engineer (Aristotle Univ. of Thessaloniki),
PhD (Aristotle Univ. of Thessaloniki),
MSc (Imperial College of London)
School of Electrical and Computer Engineering
Aristotle University of Thessaloniki
phone number : +30 (2310) 994379
</pre>
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<pre class="moz-signature" cols="72">--
George Mamalakis
IT and Security Officer,
Electrical and Computer Engineer (Aristotle Univ. of Thessaloniki),
PhD (Aristotle Univ. of Thessaloniki),
MSc (Imperial College of London)
School of Electrical and Computer Engineering
Aristotle University of Thessaloniki
phone number : +30 (2310) 994379
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