PHP: How to set memory and time limits for online compiler?

Sinedie · 02-17-2008, 03:51 AM

Hello,
I would like to develop an online compiler for competitions running on Linux. I would like to know how can I compile and execute programs submitted within specific memory limit. Would ulimit be adequate or should something more is required to constrain the process to run in the required memory limits? Please help me.

TIA,
-S

Deleriux · 02-17-2008, 07:58 AM

I believe there is php limits in php.ini to set the maximum usable memory and execution time of a php application.

Using ulimits would probably be of little use as they only work on a per-shell basis (they effect all the children of a shell). Since you might have a number of processes in the same shell the ulimit method might be skewed.

Sinedie · 02-18-2008, 05:01 AM

Quote:

Originally Posted by Deleriux

I believe there is php limits in php.ini to set the maximum usable memory and execution time of a php application.

Using ulimits would probably be of little use as they only work on a per-shell basis (they effect all the children of a shell). Since you might have a number of processes in the same shell the ulimit method might be skewed.

But if I run an executable with PHP, will the child process' memory consumption gets counted? Or is it only the scripts? I am not sure about this..., will try to run it and see...

Thanks for pointing to this Deleriux. The default value for memory_limit is 32MB. So will try to run an executable as a child process and see if it counts it.

Sinedie · 02-18-2008, 05:17 AM

I just checked and it did not prevent the child executable from taking hundreds of MB (instead of 32MB). OTOH, ulimit -v worked from shell, though doesn't seem to work with 'sh -f shell_script_name'.

Sinedie · 08-16-2008, 07:37 AM

I am still stuck with the same problem

I would need to compile and execute a C/C++/Java code from PHP as part of online compiler. Can anyone help me with a safe way of compiling and executing a script? I think chroot-ing apache will solve some problems, plus using SELinux. How could one possibly run an executable from shell using PHP with memory limits?

Thanks in advance for any information.

-S

Sinedie · 08-16-2008, 08:02 AM

I have tested the following shell script that takes a C++ program name and kills it after 5 secs. I would like to know the comments on it:

Code:

        i_file=$1
        pid=$$
        tlimit=$2
        e_file="/var/www/html/san/test/"$pid".exe"
        lock="/var/www/html/san/test/LOCK"

        ulimit -v 1020400

        while [ -f $lock ]
        do
                sleep 1
        done

        touch $lock

        echo c++ $i_file -o $e_file
        c++ $i_file -o $e_file

        $e_file &

        sleep $tlimit

        kill -9 $!
        rm -f $e_file
        rm -f $lock