compilebox/API/Payload/javaRunner.sh at master · codegrande/compilebox · GitHub

executable file

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#!/usr/bin/env sh

######################################################################################

# This script is specifically made to handle the compilation of java

# The idea is to cater with the difference of class name(s) inside file

# and the file name itself when executing the java .class files

# This script is executed after javac compiler has already compiled the file

# into classes

# The cd /usercode/ command is Docker case specific. Description is mentioned

# below.

# The script works as follows

# 1. Search the current directory for all files that have a .class extension

# 2. Run javap on the class name

# The javap tool disassembles compiled Java™ files and prints

# out a representation of the Java program. This may be helpful

# when the original source code is no longer available on a system.

# source: publib.boulder.ibm.com/infocenter/iseries/v5r4/topic/rzaha/javap.htm

# 3. If the class contains the main function run the java command to run it and exit

# 4. This script only executes the first main function it finds

# Inspired From: http://stackoverflow.com/a/8870863

#######################################################################################

#The folder which we mount on docker is named the usercode.

#Move into the directory and execute the loop

cd /usercode/

for classfile in *.class; do

classname=${classfile%.*}

#echo $classname

#Execute fgrep with -q option to not display anything on stdout when the match is found

if javap -public $classname | fgrep -q 'public static void main(java.lang.String[])'; then

java $classname "$@"

exit 0;

done

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