Script to setup and enter a chroot

chroot-enter.bash

#!/bin/bash
# Craig Hesling <[email protected]>

set -e

root="$1"

if [[ -z "$root" || ! -d "$root" ]]; then
  echo "Error: Directory '$root' does not exist"
  echo
  echo "Usage: $0 /path/to/existing/chroot/directory"
  exit 1
fi

if ! mountpoint -q "$root/proc"; then
  mount -t proc /proc "$root/proc"
fi

if ! mountpoint -q "$root/sys"; then
  mount -t sysfs /sys "$root/sys"
fi

if ! mountpoint -q "$root/dev"; then
  mount -o bind /dev "$root/dev"
fi

cp /etc/resolv.conf "$root/etc/resolv.conf"
export debian_chroot="$(basename "$root")"

# We can enable PID namespacing by uncommenting the following, but /proc
# would need to be unmounted and remounted inside the namespace. Otherwise,
# the processes would still be able to see host proc info, through the fs.
#unshare --pid --mount-proc --fork \
chroot "$root" /bin/bash