Forum OpenACS Q&A: Re: Can't exec a command in tcl page

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12: Re: Can't exec a command in tcl page (response to 1)
Posted by Jim Lynch on 07/22/14 01:24 AM
When you tested the commands using bash, did you check the exit status every time?
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13: Re: Can't exec a command in tcl page (response to 12)
Posted by Antonio Pisano on 07/22/14 03:31 PM
Thanks for the many hints guys. Sadly no luck with this by now...

I need to convert csv to xls because I need an export function which could Just Work for a customer of ours. They expect a file to be loaded in their system to be an xls, so...

Anyway, I have tried redirecting standard error (and everything else) using &> /dev/null at the end of the command, but didn't work out (same error).

Catching the exec and ispecting its output shows a CHILDSTATUS error, but this we knew already.

I have also thought it could be a matter of different current folder, so I changed the command to

/usr/bin/libreoffice --headless --convert-to xls /tmp/fileugDbjI.csv --outdir /tmp

to force output folder to be /tmp. As before, the command works fine in the shell (return code is 0)

Using exec to invoke a shell as Neophytos suggested brings to the very same behaviour.

I am out of clues... think I will try to reproduce the problem on another server to see if it is due to this particular machine/configuration or if there is something going wrong with the proxy

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16: Re: Can't exec a command in tcl page (response to 13)
Posted by Gustaf Neumann on 07/22/14 05:38 PM
The hint with the CHILDSTATUS rings a bell. In case Neo's suggestion does not help, one more idea for debugging. Write a wrapper (e.g. named /tmp/convert.sh) like the following 
#!/bin/sh
echo xxx `/usr/bin/id`
/usr/bin/libreoffice --headless --convert-to xls SOMEFILE.csv --outdir /tmp
echo "xxx $? exit code"
fill in a .csv tile for testing and call the wrapper via 
set result [exec bash /tmp/convert.sh]
i would not be wondering, when you get on your machine now a useful result now, showing a non-zero exit code from libreoffice. Maybe there is a permission problem under the userid of the server? Handing CHILDSTATUS in Tcl requires some special, which i don't see in nsproxy. Probably nsproxy has to be improved to return better errors.
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17: Re: Can't exec a command in tcl page (response to 16)
Posted by Gustaf Neumann on 07/22/14 06:16 PM
I've compared the cases, where tcl-exec and/or nsproxy-exec calls a program with a non-zero return status. In both cases, the behavior is the same, one gets the return status via the global variable ::errorCode. The following snippet shows the result code from the called program: 
set cmd {/usr/bin/libreoffice ... --outdir /tmp}
if {[catch {set result [exec {*}$cmd]} errorMsg]} {
   lassign {*}$::errorCode code id value
   if {$code eq "CHILDSTATUS"} {set result "program exited with code $value"}
}
so, the nsproxy behavior is technically correct, just the error message from tcl could be better. What return code do you get in your installation?
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20: Re: Can't exec a command in tcl page (response to 16)
Posted by Benjamin Brink on 07/23/14 12:00 AM
Gustaf writes:

"Maybe there is a permission problem under the userid of the server."

I've had this happen before.

Antonio, what happens if you use a different directory using server's owner and group same as openacs system, such as a openacs-4/tmp/ ?