scripts/hermetic-env

#!/bin/bash
# Copyright 2020 The Fuchsia Authors. All Rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This script is a replacement for /usr/bin/env that adds Fuchsia-specific
# information and provides access to prebuilt tools in the source tree.
#
# This is not a subcommand of `fx` because multiple pieces of project
# infrastructure run outside of the build and need access to in-tree prebuilts.

set -e

# Filter out invalid FUCHSIA_DIR settings.
if [[ -n "${FUCHSIA_DIR}" ]]; then
  if [[ ! -d "${FUCHSIA_DIR}" ]]; then
    unset FUCHSIA_DIR
  elif [[ "${FUCHSIA_DIR#/}" == "${FUCHSIA_DIR}" ]]; then
    unset FUCHSIA_DIR
  else
    PWD="$(pwd)"
    if [[ "${PWD#"${FUCHSIA_DIR}"}" = "${PWD}" ]]; then
      # FUCHSIA_DIR does not contain the current directory
      unset FUCHSIA_DIR
    fi
  fi
fi

# LINT.IfChange
function find_tree_root {
  local parent="$1"
  if [[ ! -d "$parent" ]]; then
    return 1
  fi
  while [[ ! -f "${parent}/.fx-root" ]]; do
    if [[ "$parent" == "/" ]]; then
      return 1
    fi
    parent="$(dirname "${parent}")"
  done
  echo "$parent"
}

# Mimic `fx` behavior to set up a consistent root and get prebuilt paths.
#
# We walk the parent directories looking for //.fx-root rather than using
# BASH_SOURCE so that we find the fuchsia_dir enclosing the current working
# directory instead of the one containing this file in case the user has
# multiple source trees and is picking up this file from another one.
#
# NOTE: The FUCHSIA_DIR environment variable is ignored here because it
# could point to a different Fuchsia checkout in some developer setups.
if ! fuchsia_dir="$(find_tree_root "$(pwd)")"; then
  echo >&2 "ERROR: Cannot find the Platform Source Tree in a parent of the current directory: $(pwd)"
  exit 1
fi

script_dir="$(dirname "$(realpath "${BASH_SOURCE[0]}")")"

# NOTE: This check MUST be executed immediately after `fuchsia_dir` is set.
# Do NOT add any metric gathering or other setup before this block, as this
# `hermetic-env` instance may be run in a foreign fuchsia checkout.
if [[ "${script_dir}/" != "${fuchsia_dir}/"* && "${script_dir}/" != "$(realpath "${fuchsia_dir}")/"* ]]; then
  # When running `hermetic-env` from `$PATH` within a foreign fuchsia checkout
  # that is owned by the current user, run the version of `hermetic-env` from
  # the foreign checkout instead.
  if [[ "$0" == *"/.jiri_root/bin/"* ]] && \
     [[ -O "${fuchsia_dir}" ]] && \
     [[ -x "${fuchsia_dir}/scripts/hermetic-env" ]]; then
    exec "${fuchsia_dir}/scripts/hermetic-env" "$@"
  fi

  echo >&2 "ERROR: You are executing hermetic-env from outside of the current source tree"
  echo >&2 "ERROR: This is not supported as fx does not have a stable internal API"
  echo >&2
  echo >&2 "    'hermetic-env' was executed from: ${BASH_SOURCE[0]}"
  echo >&2 "    'fuchsia directory' resolved to: ${fuchsia_dir}"
  echo >&2 "    'script_dir' resolved to: ${script_dir}"
  echo >&2
  echo >&2 "To run a command in the current Fuchsia directory, run hermetic-env from:"
  echo >&2 "  ${fuchsia_dir}/scripts/hermetic-env"
  echo >&2 "Or, if you use fx-env.sh, source fx-env from the current fuchsia dir:"
  echo >&2 "  source ${fuchsia_dir}/scripts/fx-env.sh"
  echo >&2 "To change your current environment, update your 'PATH':"
  echo >&2 "  source ${fuchsia_dir}/scripts/fx-env.sh && fx-update-path"
  exit 1
fi
# LINT.ThenChange(
#   //scripts/fx,
#   //scripts/zsh-completion/_fx,
#   //src/developer/ffx/scripts/ffx,
# )

export FUCHSIA_DIR="${fuchsia_dir}"
declare -r platform_sh="${fuchsia_dir}/tools/devshell/lib/platform.sh"
# shellcheck source=/dev/null
source "${platform_sh}" || exit $?

if [[ "${PATH#"${PREBUILT_ALL_PATHS}"}" == "${PATH}" ]]; then
  # Prebuilts have not been added to the path
  if [[ "${FUCHSIA_HERMETIC_TOOLS}" == "y" ]]; then
    readonly newpath="${PREBUILT_ALL_PATHS}:${FUCHSIA_DIR}/tools/system"
  else
    readonly newpath="${PREBUILT_ALL_PATHS}:${PATH}"
  fi
else
  readonly newpath="${PATH}"
fi

# Remove problematic PATH entries to avoid hermeticity errors, such
# as the one from https://fxbug.dev/530479291. The following removes
# empty path components (interpreted as the current directory), the
# current directory (.), and any relative path from PATH.
sanitized_path=""
for path in $(printf "%s" "${newpath}" | awk -v RS=: '{print}'); do
  case "${path}" in
    /*)
       # Keep this absolute path, append it to current list.
       if [[ -n "${sanitized_path}" ]]; then
         sanitized_path+=":"
       fi
       sanitized_path+="${path}"
       ;;
   "")
       echo >&2 "WARNING: Empty path component removed from PATH!"
       ;;
   .)
       echo >&2 "WARNING: Current directory removed from PATH!"
       ;;
   *)
       echo >&2 "WARNING: Relative path removed from PATH: $path"
       ;;
  esac
done

export PATH="${sanitized_path}"

# Always populate FUCHSIA_BUILD_DIR_FROM_FX.
if [[ -z "${FUCHSIA_BUILD_DIR_FROM_FX}" && -f "${FUCHSIA_DIR}/.fx-build-dir" ]]; then
  FUCHSIA_BUILD_DIR_FROM_FX=$(cd "${FUCHSIA_DIR}" && realpath "$(cat .fx-build-dir)")
  export FUCHSIA_BUILD_DIR_FROM_FX
fi

# Forward agent environment variables defined in agents.txt.
agent_env_args=()
readonly agents_file="${fuchsia_dir}/tools/devshell/lib/agents.txt"
if [[ -f "${agents_file}" ]]; then
  while IFS= read -r agent_var || [[ -n "${agent_var}" ]]; do
    [[ -z "${agent_var}" || "${agent_var}" =~ ^# ]] && continue
    if [[ -n "${!agent_var+x}" ]]; then
      agent_env_args+=("${agent_var}=${!agent_var}")
    fi
  done < "${agents_file}"
fi

# Forward the args to the system `env`.
exec /usr/bin/env -i \
  "FUCHSIA_DIR=${fuchsia_dir}" \
  "PYTHONPATH=${fuchsia_dir}" \
  "TERM=${TERM}" \
  "PATH=${newpath}" \
  "HOME=${HOME}" \
  "USER=${USER}" \
  "FUCHSIA_HERMETIC_TOOLS=${FUCHSIA_HERMETIC_TOOLS}" \
  "FUCHSIA_NODENAME=${FUCHSIA_NODENAME}" \
  "FUCHSIA_NODENAME_IS_FROM_FILE=${FUCHSIA_NODENAME_IS_FROM_FILE}" \
  "FUCHSIA_TEST_FETCH_REMOTE=${FUCHSIA_TEST_FETCH_REMOTE}" \
  ${FUCHSIA_BAZEL_DISK_CACHE+"FUCHSIA_BAZEL_DISK_CACHE=${FUCHSIA_BAZEL_DISK_CACHE}"} \
  ${FUCHSIA_BAZEL_DISK_CACHE_SIZE+"FUCHSIA_BAZEL_DISK_CACHE_SIZE=${FUCHSIA_BAZEL_DISK_CACHE_SIZE}"} \
  ${FUCHSIA_BAZEL_PRINT_COMMANDS+"FUCHSIA_BAZEL_PRINT_COMMANDS=${FUCHSIA_BAZEL_PRINT_COMMANDS}"} \
  ${FUCHSIA_BUILD_DIR_FROM_FX+"FUCHSIA_BUILD_DIR_FROM_FX=${FUCHSIA_BUILD_DIR_FROM_FX}"} \
  ${FUCHSIA_DEBUG_BAZEL_SANDBOX+"FUCHSIA_DEBUG_BAZEL_SANDBOX=${FUCHSIA_DEBUG_BAZEL_SANDBOX}"} \
  ${FX_BUILD_RBE_STATS+"FX_BUILD_RBE_STATS=${FX_BUILD_RBE_STATS}"} \
  ${FX_RA_EXPERIMENTS_ENABLED+"FX_RA_EXPERIMENTS_ENABLED=${FX_RA_EXPERIMENTS_ENABLED}"} \
  ${NINJA_STATUS+"NINJA_STATUS=${NINJA_STATUS}"} \
  ${NINJA_STATUS_MAX_COMMANDS+"NINJA_STATUS_MAX_COMMANDS=${NINJA_STATUS_MAX_COMMANDS}"} \
  ${NINJA_STATUS_REFRESH_MILLIS+"NINJA_STATUS_REFRESH_MILLIS=${NINJA_STATUS_REFRESH_MILLIS}"} \
  ${NINJA_PERSISTENT_MODE+"NINJA_PERSISTENT_MODE=${NINJA_PERSISTENT_MODE}"} \
  ${NINJA_PERSISTENT_LOG_FILE+"NINJA_PERSISTENT_LOG_FILE=${NINJA_PERSISTENT_LOG_FILE}"} \
  ${NINJA_PERSISTENT_TIMEOUT_SECONDS+"NINJA_PERSISTENT_TIMEOUT_SECONDS=${NINJA_PERSISTENT_TIMEOUT_SECONDS}"} \
  ${GOMA_DISABLED+"GOMA_DISABLED=${GOMA_DISABLED}"} \
  ${TMPDIR+"TMPDIR=${TMPDIR}"} \
  ${SSH_AUTH_SOCK+"SSH_AUTH_SOCK=${SSH_AUTH_SOCK}"} \
  ${LUCI_AUTH_CREDENTIAL_HELPER+"LUCI_AUTH_CREDENTIAL_HELPER=${LUCI_AUTH_CREDENTIAL_HELPER}"} \
  ${FUCHSIA_FX_ITERATIVE+"FUCHSIA_FX_ITERATIVE=${FUCHSIA_FX_ITERATIVE}"} \
  ${FUCHSIA_FX_TEST_RUN+"FUCHSIA_FX_TEST_RUN=${FUCHSIA_FX_TEST_RUN}"} \
  ${FUCHSIA_FX_MULTI_RUN+"FUCHSIA_FX_MULTI_RUN=${FUCHSIA_FX_MULTI_RUN}"} \
  ${FUCHSIA_FX_INVOKER+"FUCHSIA_FX_INVOKER=${FUCHSIA_FX_INVOKER}"} \
  ${XDG_DATA_HOME+"XDG_DATA_HOME=${XDG_DATA_HOME}"} \
  ${GEMINI_API_KEY+"GEMINI_API_KEY=${GEMINI_API_KEY}"} \
  ${XDG_RUNTIME_DIR+"FUCHSIA_XDG_RUNTIME_DIR_FROM_FX=${XDG_RUNTIME_DIR}"} \
  ${FUCHSIA_METRICS_CALL_STACK+"FUCHSIA_METRICS_CALL_STACK=${FUCHSIA_METRICS_CALL_STACK}"} \
  ${LLVM_PROFILE_FILE+"LLVM_PROFILE_FILE=${LLVM_PROFILE_FILE}"} \
  ${agent_env_args[@]+"${agent_env_args[@]}"} \
  "$@"