Web header corruption with cgi calls using xymonmenu.cfg and xymonpage - a workaround 🔗 link

Maybe this has been fixed in Xymon releases 4.3.11+. This is dealing with custom cgi's being placed into 
cgi-bin/cgi-secure that are calling the xymonpage procedure. Problem is being experienced in 4.3.11.

When installing/modifying a custom module, running into corrupt web content with the 
upper menu installed through the xymonmenu.cfg/XYMONBODYHEADER mechanism via xymonpage. One variables is not
being defined (XYMONSERVERSECURECGIURL) and de-referencing of another (XYMONSERVERWWWWURL) during 
execution. The latter condition is kinky; I tried tracing through xymonpage.c/headfoot.c but ended 
up getting lost. Until the XYMONSERVESECURECGIURL is ~~encountered in the xymonmenu.cfg, the XYMONSERVERWWWURL is 
being resolved.

Anyways, the problem can be demonstrated below by just setting the XYMONHOME variable and trying the three 
functions. Functions try1 and try2 are setting xymon environment using either sourcing of configuration file
or through the xymoncmd. Results of both show the variables being undefined in the web page generation. If you look 
at the whole web page generation, there is also something weird with bad ~~duplication after the Help block from
the xymonmenu.cfg (at least on my site). Oof...

One work around is to explicitly import the xymonserver.cfg content using the "--env" option with the xymonpage
call. Function try3 (and try4) works - the variables all get defined. Note: still may need to set up xymon 
environment for the first portion feeding into the xymonpage pipeline either by sourcing or via the xymoncmd.

Looking through the mail archive, noticed others reporting something similar with the custom notes editor package.
This work around may help them too.


#!/bin/sh
export XYMONHOME=<your path>/xymon/server

function try1 {
# 1) bad iteration, source in everything at parent level - this results in erratic variable
#       expansion in results, cannot find value for XYMONSERVERSECURECGIURL and XYMONSERVERWWWURL
#       initially defined but lost on first incidence of XYMONSERVERSECURECGIURL (undefined)
. ${XYMONHOME}/etc/xymonserver.cfg
echo hello | \
        ${XYMONHOME}/bin/xymonpage 

}

function try2 {
# 2) bad iteration, source in using xymoncmd - same erratic results
exec ${XYMONHOME}/bin/xymoncmd --env=${XYMONHOME}/etc/xymonserver.cfg echo hello | \
        ${XYMONHOME}/bin/xymonpage 
}

function try3 {
# 3) works, source in everything at parent level - to set up environment for initial
#       execution (the "echo hello" portion) then also re-introduce environment in
#       xymonpage using "--env" setting, xymonpage is not reliably picking up runtime
#       inherittance otherwise
exec ${XYMONHOME}/bin/xymoncmd --env=${XYMONHOME}/etc/xymonserver.cfg echo hello | \
        ${XYMONHOME}/bin/xymonpage --env=${XYMONHOME}/etc/xymonserver.cfg
}

function try4 {
# 4) works
. ${XYMONHOME}/etc/xymonserver.cfg
echo hello | \
        ${XYMONHOME}/bin/xymonpage --env=${XYMONHOME}/etc/xymonserver.cfg
}

# run test runs and filter out everything but blown variables -
#       XYMONSERVERSECURECGIURL and XYMONSERVERWWWURL

try1 2>&1 | grep -i xymonserver | head -10
#try2 2>&1 | grep -i xymonserver | head -10
#try3 2>&1 | grep -i xymonserver
#try4 2>&1 | grep -i xymonserver

Den 10.01.2014 19:56, Deiss, Mark skrev:

I think this is caused by missing out the fact that xymonserver.cfg is NOT intended to be used directly in shell scripts. As it says at the very top of xymonserver.cfg:

    # NB : Even though it might look like a shell-script, it is NOT.


So when you do this:

#!/bin/sh
export XYMONHOME=<your path>/xymon/server
. ${XYMONHOME}/etc/xymonserver.cfg

then you are doing it wrong. E.g. it won't handle any "include" or "directory" settings.

You cannot source xymonserver.cfg. The correct way of doing what you want is:

echo hello | \
         ${XYMONHOME}/bin/xymoncmd --env=${XYMONHOME}/etc/xymonserver.cfg xymonpage

In other words, you must let xymoncmd process the xymonserver.cfg file, and then have xymoncmd directly invoke the Xymon command that you want to use. You can omit the "--env" option if you compiled Xymon with the correct XYMONHOME setting.

Here xymoncmd sets up the environment for the "echo hello" command, but your SHELL does NOT pass this to the xymonpage command.

Yep, this works because xymonpage now reads xymonserver.cfg by itself. So it doesn't rely on things coming in via the environment variables. You don't need the xymoncmd at all, the "echo hello" doesn't use it (same as in 2)).

function try4 {
# 4) works
. ${XYMONHOME}/etc/xymonserver.cfg
echo hello | \
        ${XYMONHOME}/bin/xymonpage --env=${XYMONHOME}/etc/xymonserver.cfg
}

Same as 3), but the source'ing of xymonserver.cfg is both wrong and useless.


Hope this helps.


Regards,
Henrik