chroot.txt

#Configuring Chroot on your system : https://wiki.ubuntu.com/DebootstrapChroot


#install dchroot package for chroot jail
apt-get install dchroot

# /etc/schroot/schroot.conf  is  a  plain  UTF-8  text  file,  describing  the chroots available for use with sbuild.
#add information in /etc/schroot/schroot.conf
#gksu gedit is graphical super user gedit

gksu gedit schroot.conf

#add these lines

[quantal]
description=Ubuntu Quantal
location=/compileone/chroot
priority=3
users=faridi
groups=sbuild
root-groups=root


#debootstrap is a tool which will install a Debian base system into a subdirectory of another, already installed system.

apt-get install debootstrap

#create a directory to be your "jail"
mkdir compileone
cd /compileone
mkdir chroot
#now /compileone/chroot is your "jail"


#install the base file system, let say ubuntu 12.10 (quantal)
debootstrap --variant=buildd --arch i386 quantal /compileone/chroot/ http://archive.ubuntu.com/ubuntu

#mount proc directory of parent ubuntu to child proc directory for handling running process details
#so you can use commands like "ps aux" and "kill" to control processes running in the jail
mount -o bind /proc /compileone/chroot/proc


####################################Not Needed###################
#copy the "/etc/resolv.conf" file from your actual file sytem to the one in the CHROOT JAIL to enable DNS 
#resolution for programs running in the jail
cp /etc/resolv.conf /compileone/chroot/etc/resolv.conf 

#export the chroot jail display to your actual X server outside the jail to run graphical applications inside the jail
export DISPLAY=:0.0
###############################Not Needed#########################


#The chroot command allows you to temporarily change the root of the file system
#chroot jail create an isolated location from which you can run programs that are
#separated from the actual file system (like a sandbox)

chroot /compileone/chroot

#setup all the compilers and interpreters. 
apt-get update
apt-get install bf bc g++ fpc mono-gmcs openjdk-6-jdk perl php5 python python3 rhino ruby ghc



#psmisc
#This PSmisc package is a set of some small useful utilities that use the proc filesystem.
#it includes "killall" utility - kills a process by its name, similar to a pkill found in some other Unices.

#python3-pip : A tool for installing and managing Python packages.
#judge requires pymysql for db interaction

apt-get install psmisc python-pip
pip install pymysql
pip install psutil


#Finally create user 'compileone' and change permission of directories to ensure security.
#useradd
#-m : The user's home directory will be created if it does not exist.
#-u uid : The numerical value of the user's ID.Values between 0 and 99 are typically reserved for system accounts.
#-s shell : The name of the user's login shell. 	
#-p password

chmod 700 /tmp
useradd -m -u 9000 -s /bin/bash compileone -p password
cd /home/compileone
# copy and paste run.py here

#making directories with restricted permissions

mkdir env io_cache
chmod 755 env
chmod 700 io_cache

#change ownership of env to compileone
chown compileone env
#change group of env to compileone
chgrp compileone env
#change permission of run.py to read and write to owner and no permission to group or others classes
chmod 600 run.py