[Mediawiki-l] texvc

Maurizio Vitale maurizio.vitale at polymath-solutions.com
Fri Aug 10 00:13:29 UTC 2007


Try to discover how you're executing PHP and whether there's a  
setting to be enabled for allowing subprocesses
to run (it is a potential security risk, so there might be a knob  
somewhere controlling it).
Trying to serve a php file with something similar to
<?php
   $ls=`ls`;
   echo "$ls\n";
?>
might help you discovering whether subprocesses are run or not.

If you're running security enhanced linux you might have a host of  
other reasons why things fail.
I know nothing of this, but there might be traces in system logs  
about what goes wrong.

On Aug 9, 2007, at 6:24 PM, Bruno Goncalves wrote:

> Hi Maurizio,
>
> I tried adding the Sys.... to texvc.ml and recompile... the file  
> was never
> created. I had also tried to modify render.ml to include the full  
> paths for
> each tool and redirect stdout and stderr to a file instead of /dev/ 
> null,
> nothing happened (except when I run texvc by hand, of course).
> It seems that texvc is not actually being run. I just wish I knew  
> why...
>
> Bruno
>
>
> On 8/9/07, Maurizio Vitale <maurizio.vitale at polymath-solutions.com>  
> wrote:
>>
>>
>> On Aug 9, 2007, at 5:46 PM, Bruno Goncalves wrote:
>>
>>> Dear All,
>>>
>>> Any ideas? Texvc still refuses to work from inside mediawiki, but
>>> if I run
>>> the command that shows up in the debug file, it runs fine.
>>> I've modified render.ml so it doesn't delete the tex. aux, etc..
>>> files. When
>>> texvc is run "by hand" the files are where you would expect them,
>>> but when
>>> running from within mediawiki they are not created. My guess is
>>> that for
>>> some reason texvc isn't even being executed (although setting
>>> $wgTexvc='/bin/echo' works as expected). Any ideas? Without tex
>>> support
>>> mediawiki is useless to me...
>>
>> Well, I think from the symptoms seen up to now that texvc does run.
>> None of the files that it deletes are created by texvc itself(some
>> are from latex,
>> some from dvips, maybe some from dvipng), so the fact they're not
>> there doesn't
>> mean texvc doesn't run.
>>
>> If you want to be sure that texvc does run, have it modify the state.
>> You could log stuff, but I don't know how I/O is redirected or you
>> could add
>> something like:
>>         Sys.command ("touch /tmp/texvc_has_run");
>> to texvc.ml (the line after 'let _ =' is a good place)
>> [and recompile, of course]
>> if after rendering a page with <math></math> tags you find tat file
>> in /tmp
>> you can be sure that texvc has indeed been run.
>
> Another thing that may be happening is that texvc cannot execute
>> subprograms
>> because of the PATH setting.
>> If you have latex, dvips or dvipng in strange places and you reach
>> them because
>> of some weird setting of your PATH variable then you're out of luck:
>> texvc assumes they are on the exec path, but when run through PHP the
>> PATH
>> is not the same as your user path.
>>
>> Please have a look at these two things and report back how is going.
>>
>>> Sincerely,
>>>
>>> Bruno
>>>
>>> On 8/8/07, Bruno Goncalves <bgoncalves at gmail.com> wrote:
>>>>
>>>>
>>>>
>>>> On 8/8/07, Maurizio Vitale <maurizio.vitale at polymath-
>>>> solutions.com> wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Aug 8, 2007, at 11:54 AM, Bruno Goncalves wrote:
>>>>>
>>>>>> Dear All,
>>>>>>
>>>>>>>
>>>>>>>         - try to replace texvc with a shell script that  
>>>>>>> echoes the
>>>>>>> result
>>>>>>> you get from the command line.
>>>>>>>           This way you can try to isolate the problem and  
>>>>>>> know for
>>>>>>> sure
>>>>>>> whether it is a subprocess communication
>>>>>>>            issue.
>>>>>>
>>>>>>
>>>>>> setting $wgTexvc to be '/bin/echo' I get:
>>>>>>
>>>>>> TeX: /bin/echo '/var/www/html/wiki/images/tmp'
>>>>>> '/var/www/html/wiki/images/tmp' '
>>>>>> n^2' 'UTF-8'
>>>>>> TeX output:
>>>>>>  /var/www/html/wiki/images/tmp /var/www/html/wiki/images/tmp n^2
>>>>>> UTF-8
>>>>>
>>>>>>
>>>>>
>>>>> I should have been clearer. What I meant was to point $wgTexvc  
>>>>> to an
>>>>> executable file containing something like:
>>>>>
>>>>>    #!/bin/sh
>>>>>    echo "the output you're getting from the command line  
>>>>> invocation"
>>>>>    exit 0
>>>>
>>>>
>>>> humm... this just keeps getting stranger...
>>>>
>>>> if I run the same texvc command by hand I get as output:
>>>> "+7db31f1ef8b4b7d1bfcc94576455fa0a";
>>>> Using :
>>>>
>>>> #!/bin/sh
>>>> echo "+7db31f1ef8b4b7d1bfcc94576455fa0a";
>>>> exit 0;
>>>>
>>>> I get the same error. However, if I edit includes/Math.php and add
>>>>
>>>> $contents="+7db31f1ef8b4b7d1bfcc94576455fa0a";
>>>>
>>>> just after the
>>>>
>>>> $contents=`$cmd`;
>>>>
>>>> line (in effect overriding it), it works fine. So it seems to me
>>>> that, for
>>>> some reason, Math.php is able to receive the output directly from
>>>> echo (if
>>>> I set $wgTexcv to /bin/echo", but not from texvc directly or a
>>>> shell script.
>>>> I'm totally clueless at this point.
>>>>
>>>> what OS are you running your server on?
>>>>
>>>>
>>>> Red Hat Enterprise Linux 4
>>>>
>>>>  Hope somebody else out there has any ideas.
>>>> Thanks!
>>>>
>>>> Bruno
>>>>
>>>>
>>>> --
>>>> *******************************************
>>>> Bruno Miguel Tavares Goncalves, MS
>>>> PhD Candidate
>>>> Emory University
>>>> Department of Physics
>>>> Office No. N117-C
>>>> 400 Dowman Drive
>>>> Atlanta, Georgia 30322
>>>> Homepage: www.bgoncalves.com
>>>> Email: bgoncalves at gmail.com
>>>> Phone: (404) 712-2441
>>>> Fax:   (404) 727-0873
>>>> *******************************************
>>>>
>>>
>>>
>>>
>>> --
>>> *******************************************
>>> Bruno Miguel Tavares Goncalves, MS
>>> PhD Candidate
>>> Emory University
>>> Department of Physics
>>> Office No. N117-C
>>> 400 Dowman Drive
>>> Atlanta, Georgia 30322
>>> Homepage: www.bgoncalves.com
>>> Email: bgoncalves at gmail.com
>>> Phone: (404) 712-2441
>>> Fax:   (404) 727-0873
>>> *******************************************
>>> _______________________________________________
>>> MediaWiki-l mailing list
>>> MediaWiki-l at lists.wikimedia.org
>>> http://lists.wikimedia.org/mailman/listinfo/mediawiki-l
>>
>>
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>
>
>
> -- 
> *******************************************
> Bruno Miguel Tavares Goncalves, MS
> PhD Candidate
> Emory University
> Department of Physics
> Office No. N117-C
> 400 Dowman Drive
> Atlanta, Georgia 30322
> Homepage: www.bgoncalves.com
> Email: bgoncalves at gmail.com
> Phone: (404) 712-2441
> Fax:   (404) 727-0873
> *******************************************
> _______________________________________________
> MediaWiki-l mailing list
> MediaWiki-l at lists.wikimedia.org
> http://lists.wikimedia.org/mailman/listinfo/mediawiki-l




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