hermit

#!/bin/bash

set -eo pipefail

export HERMIT_USER_HOME=~

if [ -z "${HERMIT_STATE_DIR}" ]; then
  case "$(uname -s)" in
  Darwin)
    export HERMIT_STATE_DIR="${HERMIT_USER_HOME}/Library/Caches/hermit"
    ;;
  Linux)
    export HERMIT_STATE_DIR="${XDG_CACHE_HOME:-${HERMIT_USER_HOME}/.cache}/hermit"
    ;;
  esac
fi

export HERMIT_DIST_URL="${HERMIT_DIST_URL:-https://github.com/cashapp/hermit/releases/download/stable}"
HERMIT_CHANNEL="$(basename "${HERMIT_DIST_URL}")"
export HERMIT_CHANNEL
export HERMIT_EXE=${HERMIT_EXE:-${HERMIT_STATE_DIR}/pkg/hermit@${HERMIT_CHANNEL}/hermit}

if [ ! -x "${HERMIT_EXE}" ]; then
  echo "Bootstrapping ${HERMIT_EXE} from ${HERMIT_DIST_URL}" 1>&2
  INSTALL_SCRIPT="$(mktemp)"
  # This value must match that of the install script
  INSTALL_SCRIPT_SHA256="180e997dd837f839a3072a5e2f558619b6d12555cd5452d3ab19d87720704e38"
  if [ "${INSTALL_SCRIPT_SHA256}" = "BYPASS" ]; then
    curl -fsSL "${HERMIT_DIST_URL}/install.sh" -o "${INSTALL_SCRIPT}"
  else
    # Install script is versioned by its sha256sum value
    curl -fsSL "${HERMIT_DIST_URL}/install-${INSTALL_SCRIPT_SHA256}.sh" -o "${INSTALL_SCRIPT}"
    # Verify install script's sha256sum
    openssl dgst -sha256 "${INSTALL_SCRIPT}" | \
      awk -v EXPECTED="$INSTALL_SCRIPT_SHA256" \
      '$2!=EXPECTED {print "Install script sha256 " $2 " does not match " EXPECTED; exit 1}'
  fi
  /bin/bash "${INSTALL_SCRIPT}" 1>&2
fi

exec "${HERMIT_EXE}" --level=fatal exec "$0" -- "$@"