Moodle Community Sites
  1. Moodle Community Sites
  2. MDLSITE-694

Some errors in apache log files (proxy & latex)

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Minor Minor
    • Resolution: Fixed
    • Component/s: moodle.org
    • Labels:
      None
    • Rank:
      25533

      Description

      Hi, was looking apace error logs in moodle.org, looking for some causes for recent problems in the M & P database activity... when I've detected TONS of entries like these:

      sh: /usr/bin/latex: No such file or directory
      sh: /usr/bin/dvips: No such file or directory
      sh: /usr/bin/latex: No such file or directory
      sh: /usr/bin/latex: No such file or directory
      sh: /usr/bin/latex: No such file or directory
      sh: /usr/bin/dvips: No such file or directory
      sh: /usr/bin/dvips: No such file or directory
      sh: /usr/bin/dvips: No such file or directory

      and

      [Wed Mar 25 01:56:05 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19585 for worker proxy:reverse
      [Wed Mar 25 01:56:06 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19588 for worker proxy:reverse
      [Wed Mar 25 01:56:06 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19589 for worker proxy:reverse
      [Wed Mar 25 01:56:07 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19593 for worker proxy:reverse
      [Wed Mar 25 01:56:07 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19594 for worker proxy:reverse
      [Wed Mar 25 01:56:07 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19592 for worker proxy:reverse
      [Wed Mar 25 01:56:07 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19595 for worker proxy:reverse
      [Wed Mar 25 01:56:08 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19596 for worker proxy:reverse
      [Wed Mar 25 01:56:08 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19597 for worker proxy:reverse
      [Wed Mar 25 01:56:08 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19598 for worker proxy:reverse
      [Wed Mar 25 01:56:08 2009] [error] proxy: ap_get_scoreboard_lb(3) failed in child 19599 for worker proxy:reverse

      Seems the the latex filter is miss configured (we should be using internal mimetex) and also something is wrong with proxy... perhaps the reverse entry is missing? Take a look to talk.moodle.org apache conf (I think I added there the two proxy rules). Perhaps that will fix the problem...

      Ciao

        Activity

        Eloy Lafuente (stronk7) created issue -
        Hide
        Mauno Korpelainen added a comment -

        Is there any chance to install some distribution of latex (for example TeX Live 2008) or change the current values from Administration > Modules > Filters > Manage filters > Tex filter to point the existing Path of latex binary, Path of dvips binary and Path of convert binary (Ghostscript or ImageMagick)

        TeX filter is trying to find the default paths first and if they are not found mimetex is used (mimetex.linux or symbolic link to existing mimetex elsewhere)

        Debugging TeX gives

        Checking executables
        Error: latex executable (/usr/bin/latex) is not readable
        Error: dvips executable (/usr/bin/dvips) is not readable
        Error: convert executable (/usr/bin/convert) is not readable

        so either those files are not readable (and not executable either) or do not exist at all.

        Show
        Mauno Korpelainen added a comment - Is there any chance to install some distribution of latex (for example TeX Live 2008) or change the current values from Administration > Modules > Filters > Manage filters > Tex filter to point the existing Path of latex binary, Path of dvips binary and Path of convert binary (Ghostscript or ImageMagick) TeX filter is trying to find the default paths first and if they are not found mimetex is used (mimetex.linux or symbolic link to existing mimetex elsewhere) Debugging TeX gives Checking executables Error: latex executable (/usr/bin/latex) is not readable Error: dvips executable (/usr/bin/dvips) is not readable Error: convert executable (/usr/bin/convert) is not readable so either those files are not readable (and not executable either) or do not exist at all.
        Hide
        Jordan Tomkinson added a comment -

        Both issues solved.

        tetex-latex installed, providing /usr/bin/latex and /usr/bin/dvips

        The proxy issues were because apache was reloaded when it should have been restarted when mod_proxy was enabled - this is a known issue with apache and it has now been stopped & started properly.

        Show
        Jordan Tomkinson added a comment - Both issues solved. tetex-latex installed, providing /usr/bin/latex and /usr/bin/dvips The proxy issues were because apache was reloaded when it should have been restarted when mod_proxy was enabled - this is a known issue with apache and it has now been stopped & started properly.
        Jordan Tomkinson made changes -
        Field Original Value New Value
        Status Open [ 1 ] Resolved [ 5 ]
        Resolution Fixed [ 1 ]
        Hide
        Mauno Korpelainen added a comment -

        Thanks Jordan!

        I made a short test in my profile and it looks cleaner than with Mimetex now - all AMS commands are not supported in forums like they are in mediawiki (since Eloy installed TeX Live to that server) but those equations that are supported look nice. Images are still gif but they can be changed to png later if TeX filter is modified for moodle 2.0...

        I could test next week which commands do work and give some examples to Moodle Docs about writing Maths with current distro.

        Show
        Mauno Korpelainen added a comment - Thanks Jordan! I made a short test in my profile and it looks cleaner than with Mimetex now - all AMS commands are not supported in forums like they are in mediawiki (since Eloy installed TeX Live to that server) but those equations that are supported look nice. Images are still gif but they can be changed to png later if TeX filter is modified for moodle 2.0... I could test next week which commands do work and give some examples to Moodle Docs about writing Maths with current distro.
        Hide
        Eloy Lafuente (stronk7) added a comment -

        Hi,

        just wanted to ping you about this security (open) issue: MDL-18552

        Not sure if tetex is affected... but IMO that bug should be fixed ASAP (there is one tentative patch there).

        IMO, it would be interesting to know the impressions about the patch, and if it's missing some other dangerous commands from some TeX guru like... Mauno? (sadly he hasn't access to the security bug afaik).

        (adding Martin here to let him know about)

        Show
        Eloy Lafuente (stronk7) added a comment - Hi, just wanted to ping you about this security (open) issue: MDL-18552 Not sure if tetex is affected... but IMO that bug should be fixed ASAP (there is one tentative patch there). IMO, it would be interesting to know the impressions about the patch, and if it's missing some other dangerous commands from some TeX guru like... Mauno? (sadly he hasn't access to the security bug afaik). (adding Martin here to let him know about)
        Hide
        Mauno Korpelainen added a comment -

        I don't have access to that bug but I suppose you mean the injection through tex filter that required register_globals to be on...

        I'm not aware of any dangers in tex itself - the main problem should be on those sites that allow writing in directly web accessible folders - or remote file injections/attacks through them.

        Show
        Mauno Korpelainen added a comment - I don't have access to that bug but I suppose you mean the injection through tex filter that required register_globals to be on... I'm not aware of any dangers in tex itself - the main problem should be on those sites that allow writing in directly web accessible folders - or remote file injections/attacks through them.
        Hide
        Mauno Korpelainen added a comment -

        You are right Eloy - that bug must be fixed ASAP

        I can try to do some extra research about possible missing commands tomorrow - right now I'm just feeling busy and really_really_really_small...

        Show
        Mauno Korpelainen added a comment - You are right Eloy - that bug must be fixed ASAP I can try to do some extra research about possible missing commands tomorrow - right now I'm just feeling busy and really_really_really_small...
        Martin Dougiamas made changes -
        Workflow jira [ 31237 ] SITES Full Workflow [ 126116 ]
        Martin Dougiamas made changes -
        Status Resolved [ 5 ] Closed [ 6 ]

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              Updated:
              Resolved:

              Development