#!/bin/bash

DISCOCFG=/etc/disco
DISCOROOT=/var/disco/testfs

mount | grep $DISCOROOT >/dev/null 2>&1
if [ $? -eq 0 ]; then
    echo "disco chroot is already mounted, please exec disco-fs-unmount and try again."
    exit 1
fi

# Cleanup old junk
rm -rf ${DISCOROOT}/scratchfs
rm -rf ${DISCOROOT}/restricted/*
rm -rf ${DISCOROOT}/munge/*

# Prepare all the mountpoint directories
mkdir -p ${DISCOROOT}/chroot
#mkdir -p ${DISCOROOT}/proc/proc
#mkdir -p ${DISCOROOT}/sysfs/sys
mkdir -p ${DISCOROOT}/rootfs
mkdir -p ${DISCOROOT}/scratchfs
mkdir -p ${DISCOROOT}/munge
mkdir -p ${DISCOROOT}/dev/dev
mkdir -p ${DISCOROOT}/restricted/bin

# Setup all the commands for the bash restricted execution environment

mkdir -p ${DISCOCFG}/restricted.d
for file in $(cat ${DISCOCFG}/restricted.d/* 2>/dev/null | grep -v "^#")
do
    if [ ! -e ${DISCOROOT}/restricted/bin/$(basename $file) ]; then
	ln -s $file ${DISCOROOT}/restricted/bin/$(basename $file)
    fi
done

# Setup some more restricted execution stuff, but only if we actually have $NOOP

if [ "$NOOP" != "" ]; then
    # Munge up /etc/profile
    mkdir -p ${DISCOROOT}/munge/etc
    cp /etc/profile ${DISCOROOT}/munge/etc/profile
    echo "export PATH=${DISCOROOT}/restricted/bin" >> ${DISCOROOT}/munge/etc/profile

    # Make default wrapper
    echo -e "#!/bin/bash\necho \"info: Would execute : \$(basename \$0) \$@\"" > ${DISCOROOT}/restricted/bin/_disco_restricted_cmd
    chmod +x ${DISCOROOT}/restricted/bin/_disco_restricted_cmd

    # Now link everything to the default wrapper
    for dir in $(echo $PATH | sed s/":"/" "/g)
    do
	for file in ${dir}/*
	do
	    FNAME=$(basename $file)
	    if [ "$FNAME" != "bash" ] && [ -x $file ] && [ ! -x ${DISCOROOT}/restricted/bin/$FNAME ] ; then
		ln -s ${DISCOROOT}/restricted/bin/_disco_restricted_cmd ${DISCOROOT}/restricted/bin/${FNAME}
	    fi
	done
    done
fi

# We need SOME special files in /dev like /dev/null, so make them here

mknod ${DISCOROOT}/dev/dev/null c 1 3
chmod 666 ${DISCOROOT}/dev/dev/null

# Mount all the (real filesystem) layers individually

mount --bind -o ro / ${DISCOROOT}/rootfs 2>&1 | grep -v "seems to be mounted read-write"
mount -o remount,ro ${DISCOROOT}/rootfs

# Setup filesystem layers. The read/write ones go on the top, with scratchfs ALWAYS on top.
FSLAYERS="${DISCOROOT}/scratchfs=rw"
FSLAYERS="${FSLAYERS}:${DISCOROOT}/munge=ro"
FSLAYERS="${FSLAYERS}:${DISCOROOT}/dev=rw"
#FSLAYERS="${FSLAYERS}:${DISCOROOT}/proc=ro"
#FSLAYERS="${FSLAYERS}:${DISCOROOT}/sysfs=ro"
FSLAYERS="${FSLAYERS}:${DISCOROOT}/rootfs=ro"

# Union
unionfs -o cow,dev,dirs=$FSLAYERS ${DISCOROOT}/chroot

# Duplicate /proc and /sys if they already exist
mount | grep " on /proc" >/dev/null 2>&1
if [ $? -eq 0 ]; then
    mount -t proc -o ro none ${DISCOROOT}/chroot/proc
fi
mount | grep " on /sys" >/dev/null 2>&1
if [ $? -eq 0 ]; then
    mount -t sysfs -o ro none ${DISCOROOT}/chroot/sys
fi

exit 0