chr - chroot(1) helper (too bad and ugly)

#!/bin/bash

#### $ which chr
#### /opt/scripts/chr
#### $ cat /etc/sudoers.d/_opt_scripts_chr
#### %sudo ALL=(ALL:ALL) NOPASSWD: /opt/scripts/chr

test -z "$1" && exit 1

# : ${CHR_ROOT:=$1}
CHR_ROOT=$(readlink -e "$1")
if test ! -d "${CHR_ROOT}"; then CHR_ROOT=$(readlink -e "/home/$1"); fi
test ! -d "${CHR_ROOT}" && echo 'not found' && exit 1

: ${CHR_WRAP:=$2}
: ${CHR_HOME:=$3}
: ${CHR_HOME:=${HOME}}
: ${CHR_PIPE:=${CHR_HOME}/gentoo}

test $(id -u) != 0 && exec sudo -n $0 "${CHR_ROOT}" "${CHR_WRAP}" "${CHR_HOME}"
test $(id -u) != 0 && echo 'cant call myself with sudo' && exit 1

MNT_LIST=''
MNT_TMPFS='/tmp /var/cache/apt/archives /var/lib/apt/lists /run'
MNT_BIND='/sys /proc /dev /dev/pts /dev/shm /proc/sys/fs/binfmt_misc'
DIR_FIXUP='/run/lock /run/user'

if test -d "${CHR_PIPE}"; then
    MNT_BIND=${MNT_BIND}" ${CHR_PIPE}:/gentoo"
fi

for i in ${MNT_TMPFS[@]}; do
    d=${CHR_ROOT}$i
#   test ! -d "$i" && continue
    mount -t tmpfs -o size=70% tmpfs "$d"
    MNT_LIST=$d' '${MNT_LIST}
done
for i in ${MNT_BIND[@]}; do
    s=$i
    d=${CHR_ROOT}$i
#   if echo "$i" | fgrep -qe ':'; then
    if [[ "$i" =~ ':' ]]; then
    #   s=$(echo "$i" | cut -d':' -f1)
        s=${i%:*}
    #   d=${CHR_ROOT}$(echo "$i" | cut -d':' -f2)
        d=${CHR_ROOT}${i#*:}
    fi
#   test ! -d "$d" && continue
    mount --bind "$s" "$d"
    MNT_LIST=$d' '${MNT_LIST}
done
for i in ${DIR_FIXUP[@]}; do
    mkdir -p "${CHR_ROOT}$i"
done

ionice -c 3 nice -n +40 ${CHR_WRAP} chroot "${CHR_ROOT}" login -f root

for i in ${MNT_LIST[@]}; do
#   test ! -d "$i" && continue
    umount -f -l "$i"
done

if test -d "${CHR_PIPE}"; then
    ug=$(stat -c %U:%G "${CHR_PIPE}")
#   find "${CHR_PIPE}" \
#       \( -exec chown -c ${ug} {} + -exec chmod -c a+r,u+w,go-w {} + \) , \
#       \( -perm /0100 -exec chmod -c a+x {} + \)
    find "${CHR_PIPE}" \
        \( -exec chown -c ${ug} {} + \) , \
        \(   -perm /0100 -exec chmod -c 755 {} + \) , \
        \( ! -perm /0100 -exec chmod -c 644 {} + \)
fi