enter a development chroot and run a command

develenv.sh

#!/bin/ksh
 
## configuration
CHROOT=$HOME/sid-debootstrap
USER=rsdy
USER_HOME=/home/$USER
WORKDIR=$USER_HOME/build
TERM=rxvt-unicode
PATH_EXTEND='$HOME/.cabal/bin'
BIND_LIST="/dev /proc /sys"

## halt. hammerzeit.
MOUNTDIR=$CHROOT/$WORKDIR
ENV="TERM=$TERM; \
	HOME=$USER_HOME; \
	PATH=$PATH_EXTEND:\$PATH; \
	cd $WORKDIR;"
COMMAND="$ENV ${@:-bash}"

bind_if_not_mounted()
{
	params=($@)
	grep -qv ${params[${#params[*]} -1]} /proc/mounts && sudo mount -o bind $@
}

bind_mount_list()
{
	for i in $BIND_LIST; do
		bind_if_not_mounted "$i" "$CHROOT/$i"
	done
}

unbind_mount_list()
{
	for i in $BIND_LIST; do sudo umount "$CHROOT/$i"; done
}

bind_mount_list
bind_if_not_mounted $(pwd) "$MOUNTDIR"

sudo chroot --userspec="$USER:$USER" "$CHROOT" /bin/bash -c "$COMMAND"

sleep 1 # this is obviously the perfect way to handle race conditions that may occur
sudo umount "$MOUNTDIR"

unbind_mount_list