Chroot script for use with locked down Linux based NAS OSes

alpine-chroot.sh

#!/bin/sh

basepath=$(dirname "${0}")

if [ "${basepath}" = "." ]
then
  alpine="${PWD}/alpine"
else
  alpine="${basepath}/alpine"
fi

#Folder to check for
folders="proc sys dev "

for i in ${folders}
do
    mkdir -p "${alpine}"/"${i}"
done


mount -t proc  none             "${alpine}/proc"
mount -t sysfs /sys             "${alpine}/sys" 		-o ro
mount --bind   /dev             "${alpine}/dev"
mount --bind   /dev/sda		"${alpine}/dev/sda"
mount --bind   /dev/sdb		"${alpine}/dev/sdb"
if [ -f /etc/resolv.conf ] ; then cp /etc/resolv.conf "${alpine}/etc/resolv.conf" ; fi

chroot "${alpine}" ${1}

umount -R "${alpine}/proc"
umount -R "${alpine}/sys"
umount -R "${alpine}/dev"