Re: mod_php vs context: tight loop

[Hans Hagen <pragma@wxs.nl>]

On 25-11-2011 06:12, Brendan Jurd wrote:
> Hello list,
>
> I have a PHP application which generates documentation on the fly with
> context. This has been working really well, but I am now testing
> deployment on a new server with a more recent version of context, and it
> seems to be somehow getting itself into a tight loop.
>
> When I run texexec via the mod_php apache module, the command never
> returns, and `ps ax` shows the following:
>
> 9709 ? S 0:00 sh -c texexec --check 2>&1
> 9710 ? S 0:00 /bin/sh /usr/bin/texexec --check
> 9711 ? R 9:59 /usr/bin/texlua /usr/bin/mtxrun --usekpse --execute
> texexec --check
>
> `top` shows the mtxrun process eating 99.9% CPU. Attaching an strace to
> this process, once it is underway, shows no output.
>
> My test script is as follows:
>
> <?php
> $result = null;
> system("texexec --check 2>&1", $result);
> print $result . "\n";
> ?>
>
> When this same test script is run directly from the command line with
> `php5 -f test.php`, it works as expected and outputs the following:
>
> MTXrun | kpse fallback with progname 'context' initialized in 0.01
> secondsTeXExec | current distribution: web2c
> TeXExec | context source date: 2010.07.30 11:35
> TeXExec | format path: . /root/.texmf-config/web2c/luatex
> /root/.texmf-var/web2c/luatex /root/texmf/web2c/luatex
> /etc/texmf/web2c/luatex /var/lib/texmf/web2c/luatex
> /usr/local/share/texmf/web2c/luatex /usr/share/texmf/web2c/luatex
> /usr/share/texmf-texlive/web2c/luatex /root/.texmf-config/web2c
> /root/.texmf-var/web2c /root/texmf/web2c /etc/texmf/web2c
> /var/lib/texmf/web2c /usr/local/share/texmf/web2c /usr/share/texmf/web2c
> /usr/share/texmf-texlive/web2c
> TeXExec | start of analysis
> TeXExec | end of analysis
> TeXExec |
> TeXExec | TeXExec | version 6.2.1 - 1997-2009 - PRAGMA ADE/POD
>
> 0
>
> Using --timeout=30 in the arguments to texexec makes no difference;
> mtxrun nonetheless runs forever until it is signalled.
>
> It seems that this must be down to some kind of difference in Apache's
> execution environment -- I don't see any other way to explain the same
> PHP code working in cli and failing in mod_php, even when running as the
> same user. But what possible environmental factor could lead to mtxrun
> freaking out like this? I'm hoping someone on this list may be able to
> point me in the right direction.
>
> This server is a VZ instance running under proxmox, with the following
> relevant ubuntu packages installed (per the 'natty' release):
>
> context 2010.07.30-1
> libapache2-mod-php5 5.3.5-1ubuntu7.3
> apache2 2.2.17-1ubuntu1.4

in such cases I always run with --batch to make sure that the job itself 
cannot block

i have no clue

Hans

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                                           Hans Hagen | PRAGMA ADE
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