A script to bootstrap Gentoo on a Chromebook

bootstrap.sh

#!/bin/bash

set -e

if [ "${UID}" = "0" ]; then
  echo "Error: ${0} must not be run as root.";
  exit 3;
fi

TMPDIR="$(mktemp -d)"

UNAME_M="$(uname -m)"

MIRROR="${MIRROR:-http://distfiles.gentoo.org/releases}"

INSTALL_DIR="${INSTALL_DIR:-/usr/local}"
PREFIX="${PREFIX:-${INSTALL_DIR}/gentoo}"
EPREFIX="${EPREFIX:-${INSTALL_DIR}/prefix}"

if [ "${UNAME_M}" = "x86_64" ] || [ "${UNAME_M}" = "aarch64" ]; then
  read -p "Do you want to install a 32-bit Prefix to run old applications? [Y/n] ";
  case "${REPLY}" in
    [nN]* )
      echo "OK, that's fine. Let's continue.";
      ;;
    [yY]* )
      case "${UNAME_M}" in
        x86_64)
          UNAME_M=i686;
          ;;
        aarch64)
          UNAME_M=armv7l;
          ;;
      esac
      PREFIX="${PREFIX}32";
      EPREFIX="${EPREFIX}32";
      echo "Got it. Your 32-bit Prefix will be installed in ${EPREFIX}.";
      ;;
    *)
      echo "I'm sorry, I must've made a mistake somewhere. Did you say something other than yes or no?"
      exit 1;;
  esac
fi

GITWEB_SCRIPTS="${GITWEB_SCRIPTS:-https://gitweb.gentoo.org/repo/proj/prefix.git/plain/scripts}"

case "${UNAME_M}" in
  x86_64)
    GENTOO_ARCH=amd64;
    BITS=64;
    ARCH="${GENTOO_ARCH}";
    ;;
  i686)
    GENTOO_ARCH=x86;
    BITS=32;
    ARCH="${UNAME_M}";
    ;;
  armv7l)
    GENTOO_ARCH=arm;
    BITS=32;
    ARCH=armv7a_hardfp;
    ;;
  aarch64)
    GENTOO_ARCH=arm64;
    BITS=64;
    ARCH="${GENTOO_ARCH}";
    MIRROR="http://distfiles.gentoo.org/experimental";
    DIST_URL="${MIRROR}/${GENTOO_ARCH}";
    STAGE3_URL="${DIST_URL}/old/stage3-${ARCH}-20190115.tar.bz2";
    ;;
  *)
    echo "Bootstrapping Gentoo Prefix on your Chromebook is not supported.";
    exit 1;;
esac

if [ "${UNAME_M}" != "aarch64" ]; then
  DIST_URL="${MIRROR}/${GENTOO_ARCH}/autobuilds"
  STAGE3_URL="${DIST_URL}/$(curl -Ls ${DIST_URL}/latest-stage3-${ARCH}.txt | sed '/^#/d' | cut -d' ' -f1)"
fi

STAGE3="${STAGE3_URL##*/}"
OUTPUT="${TMPDIR}/${STAGE3}"

echo "Downloading stage 3..."
curl --progress-bar --output "${OUTPUT}" "${STAGE3_URL}"

echo "Done. Unpacking stage 3..."
echo -e "Warning: All data in ${PREFIX} and ${EPREFIX} will be lost. To stop this, please press ^C in the next 15 seconds.\a"
sleep 15
echo -e "\aContinuing..."
sudo umount -Rl "${PREFIX}/proc" 2>/dev/null || :
sudo umount -Rl "${PREFIX}/dev" 2>/dev/null || :
sudo umount -Rl "${PREFIX}/sys" 2>/dev/null || :
sudo rm -rf "${PREFIX}" "${EPREFIX}"
sudo mkdir -p "${PREFIX}/${EPREFIX}"
sudo chown chronos:chronos "${PREFIX}/${EPREFIX}"
sudo tar xphf "${OUTPUT}" --xattrs-include='*.*' --numeric-owner -C "${PREFIX}"
rm -rf "${TMPDIR}"

echo "Downloading bootstrap script..."
sudo curl --progress-bar --output "${PREFIX}/bootstrap-prefix.sh" -L "${GITWEB_SCRIPTS}/bootstrap-prefix.sh"
sudo chmod a+x "${PREFIX}/bootstrap-prefix.sh"

echo "Creating wrapper script..."
echo "#! /bin/sh

set -e

useradd -u 1000 -s /bin/bash chronos
export CHOST=\"\$(gcc -dumpmachine | sed -i 's,armv7a-unknown-linux-gnueabihf,armv7l-pc-linux-gnu,g')\"
emerge-webrsync
ACCEPT_KEYWORDS=\"~${GENTOO_ARCH}\" emerge -1 glibc
setarch linux${BITS} su chronos -c \"/bootstrap-prefix.sh \${1} \${2}\"
" | sudo tee "${PREFIX}/bootstrap-wrapper.sh" >/dev/null
sudo chmod a+x "${PREFIX}/bootstrap-wrapper.sh"

echo "Running wrapper script..."
sudo mount -t proc procfs "${PREFIX}/proc"
sudo mount --rbind /dev "${PREFIX}/dev"
sudo mount --make-rslave "${PREFIX}/dev"
sudo mount --rbind /sys "${PREFIX}/sys"
sudo mount --make-rslave "${PREFIX}/sys"
sudo cp -L /etc/resolv.conf "${PREFIX}/etc/"
sudo chroot "${PREFIX}" /bootstrap-wrapper.sh "${EPREFIX}" "noninteractive"
sudo mv "${PREFIX}/${EPREFIX}" "${INSTALL_DIR}/"
sudo umount -Rl "${PREFIX}/proc" || :
sudo umount -Rl "${PREFIX}/dev" || :
sudo umount -Rl "${PREFIX}/sys" || :
sudo rm -rf "${PREFIX}"
echo -e "\nGentoo Prefix has been installed; to run it, use this command: ${EPREFIX}/startprefix"