dotfiles/bin/setup-chroot

#!/usr/bin/bash
# SPDX-License-Identifier: MPL-2.0
# A mini scirpt to handle chrooting into different environments,
# especially for Alpine Linux devenv on chroots instead of containers/VMs.

# Chroot command is optional and assume login binary
CHROOT_COMMAND=${2:-"/usr/bin/login"}
TARGET_DIR=$1

if [[ $TARGET_DIR == "" ]]; then
  echo "Usage: $0 TARGET_DIR [CHROOT_COMMAND]"
  exit 1
fi

if [ $EUID != "0" ]; then
  echo "error: Must be root to proceed!"
  exit 1
fi

echo "===> Mounting required parts for chroot operation..."
mount -o bind /dev "$TARGET_DIR/dev"
mount -t proc none "$TARGET_DIR/proc"
mount -o bind /sys "$TARGET_DIR/sys"
echo "     Kernel and device mount setup done!"
sleep 3

if [[ -f "$TARGET_DIR/setup-chroot-env.sh" ]]; then
   echo "===> Preparing chroot environment..."
  if ! bash "$TARGET_DIR/setup-chroot-env.sh"; then
     echo "!    Chroot env setup failed, please proceed at your own risk."
  else
     echo "     Setup done!"
  fi
  sleep 3
fi

echo "===> Teleporting to the chroot environment in 3 seconds..."
sleep 3
exec chroot "$TARGET_DIR" "${CHROOT_COMMAND}"