#!/bin/bash

#
# Usage: ./create_chroot_env username
#

# Here specify the apps you want into the enviroment
APPS="/bin/bash /bin/ls /bin/mkdir /bin/mv /bin/pwd /bin/rm \
/usr/bin/id /usr/bin/rsync /bin/ping \
/bin/cp /bin/chmod /bin/cat /usr/local/libexec/sftp-server"

# Sanity check
if [ "$1" = "" ] ; then
	echo "	  Usage: ./create_chroot_env username"
	exit
fi

# Obtain username and HomeDir
CHROOT_USERNAME=$1
HOMEDIR=`grep /etc/passwd -e "^$CHROOT_USERNAME"  | cut -d':' -f 6`
chmod 711 $HOMEDIR
cd $HOMEDIR

# Create Directories no one will do it for you
mkdir etc
mkdir bin
mkdir dev
mkdir -p usr/bin
mkdir -p usr/local/{bin,libexec}

# Create short version to /usr/bin/groups 
# On some system it requires /bin/sh, which is generally unnessesary in a chroot cage

echo "#!/bin/bash" > usr/bin/groups
echo "id -Gn" >> usr/bin/groups

# Add some users to ./etc/paswd
grep /etc/passwd -e "^root" -e "^$CHROOT_USERNAME" > etc/passwd
grep /etc/group -e "^root" -e "^$CHROOT_USERNAME" > etc/group

# Copy the apps and the related libs
for prog in $APPS;  do
	cp $prog ./$prog
	
	# obtain a list of related libraryes
	ldd $prog > /dev/null
	if [ "$?" = 0 ] ; then 
		LIBS=`ldd $prog | awk '{ print $3 }'`
		for l in $LIBS; do
			mkdir ./`dirname $l` > /dev/null 2>&1
			cp $l ./$l
		done
	fi
done

# From some strange reason these 3 libraries are not in the ldd output, but without them 
# some stuff will not work, like usr/bin/groups
cp  /lib/libnss_compat.so.2 /lib/libnsl.so.1 /lib/libnss_files.so.2 ./lib/

# My original openssh'settings needs
cp -L /lib/ld-linux.so.2 ./lib/
cp /etc/{ld.so.cache,ld.so.conf,localtime} ./etc/
cp -a /dev/{null,random,zero} ./dev/