remoting/host/installer/linux/setup-session-environment

#!/usr/bin/env python3
# Copyright 2026 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""A script to manage systemd user environment variables for CRD sessions."""

import argparse
import json
import os
import subprocess
import sys


def start():
  """Sets environment variables for a new session."""
  # Locate the remote-session-info tool in the same directory as this script.
  script_dir = os.path.dirname(os.path.realpath(__file__))
  remote_session_info_path = os.path.join(script_dir, 'remote-session-info')
  if not os.path.exists(remote_session_info_path):
    return
  try:
    # Execute remote-session-info and parse its JSON output.
    output = subprocess.check_output(
        [remote_session_info_path], universal_newlines=True
    )
    session_info = json.loads(output)
  except (
      subprocess.CalledProcessError,
      json.JSONDecodeError,
      FileNotFoundError,
  ) as e:
    print(f'Failed to get session info: {e}', file=sys.stderr)
    return

  # If this is a CRD session, set the relevant environment variables.
  if session_info.get('isCrdSession'):
    try:
      subprocess.run([
          'systemctl',
          '--user',
          'set-environment',
          'CHROME_REMOTE_DESKTOP_SESSION=1',
      ])
      ssh_auth_sock = session_info.get('sshAuthSock')
      if ssh_auth_sock:
        subprocess.run([
            'systemctl',
            '--user',
            'set-environment',
            f'SSH_AUTH_SOCK={ssh_auth_sock}',
        ])
    except subprocess.CalledProcessError as e:
      print(f'Failed to set environment variables: {e}', file=sys.stderr)


def stop():
  """Unsets environment variables when session ends."""
  # Check the current systemd user environment to see if it was set by CRD.
  env_output = subprocess.check_output(
      ['systemctl', '--user', 'show-environment'], universal_newlines=True
  )
  # Check if CHROME_REMOTE_DESKTOP_SESSION is present in the environment.
  if any(
      line.startswith('CHROME_REMOTE_DESKTOP_SESSION=')
      for line in env_output.splitlines()
  ):
    try:
      subprocess.run([
          'systemctl',
          '--user',
          'unset-environment',
          'CHROME_REMOTE_DESKTOP_SESSION',
          'SSH_AUTH_SOCK',
      ])
    except subprocess.CalledProcessError as e:
      print(f'Failed to unset environment variables: {e}', file=sys.stderr)


def main():
  parser = argparse.ArgumentParser(
      description=(
          'Inject or cleanup systemd environment variables for Chrome Remote'
          ' Desktop sessions.'
      )
  )
  group = parser.add_mutually_exclusive_group(required=True)
  group.add_argument(
      '--start',
      action='store_true',
      help='Set environment variables for a new session.',
  )
  group.add_argument(
      '--stop',
      action='store_true',
      help='Unset environment variables when session ends.',
  )
  args = parser.parse_args()

  if args.start:
    start()
  elif args.stop:
    stop()


if __name__ == '__main__':
  main()