text: """Utilities for all Let's Encrypt."""
  import collections
  import errno
  import logging
  import os
  import re
  import subprocess
  import stat
  
  from letsencrypt import errors
  
  
  logger = logging.getLogger(__name__)
  
  
  Key = collections.namedtuple("Key", "file pem")
  # Note: form is the type of data, "pem" or "der"
  CSR = collections.namedtuple("CSR", "file data form")
  
  
  # ANSI SGR escape codes
  # Formats text as bold or with increased intensity
  ANSI_SGR_BOLD = '\033[1m'
  # Colors text red
  ANSI_SGR_RED = "\033[31m"
  # Resets output format
  ANSI_SGR_RESET = "\033[0m"
  
  
  def run_script(params):
      """Run the script with the given params.
  
      :param list params: List of parameters to pass to Popen
  
      """
      try:
          proc = subprocess.Popen(params,
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.PIPE)
  
      except (OSError, ValueError):
          msg = "Unable to run the command: %s" % " ".join(params)
          logger.error(msg)
          raise errors.SubprocessError(msg)
  
      stdout, stderr = proc.communicate()
  
      if proc.returncode != 0:
          msg = "Error while running %s.\n%s\n%s" % (
              " ".join(params), stdout, stderr)
          # Enter recovery routine...
          logger.error(msg)
          raise errors.SubprocessError(msg)
  
      return stdout, stderr
  
  
  def exe_exists(exe):
      """Determine whether path/name refers to an executable.
  
      :param str exe: Executable path or name
  
      :returns: If exe is a valid executable
      :rtype: bool
  
      """
      def is_exe(path):
          """Determine if path is an exe."""
          return os.path.isfile(path) and os.access(path, os.X_OK)
  
      path, _ = os.path.split(exe)
      if path:
          return is_exe(exe)
      else:
          for path in os.environ["PATH"].split(os.pathsep):
              if is_exe(os.path.join(path, exe)):
                  return True
  
      return False
  
  
  def make_or_verify_dir(directory, mode=0o755, uid=0, strict=False):
      """Make sure directory exists with proper permissions.
  
      :param str directory: Path to a directory.
      :param int mode: Directory mode.
      :param int uid: Directory owner.
  
      :raises .errors.Error: if a directory already exists,
          but has wrong permissions or owner
  
      :raises OSError: if invalid or inaccessible file names and
          paths, or other arguments that have the correct type,
          but are not accepted by the operating system.
  
      """
      try:
          os.makedirs(directory, mode)
      except OSError as exception:
          if exception.errno == errno.EEXIST:
              if strict and not check_permissions(directory, mode, uid):
                  raise errors.Error(
                      "%s exists, but it should be owned by user %d with"
                      "permissions %s" % (directory, uid, oct(mode)))
          else:
              raise
  
  
  def check_permissions(filepath, mode, uid=0):
      """Check file or directory permissions.
  
      :param str filepath: Path to the tested file (or directory).
      :param int mode: Expected file mode.
      :param int uid: Expected file owner.
  
      :returns: True if `mode` and `uid` match, False otherwise.
      :rtype: bool
  
      """
      file_stat = os.stat(filepath)
      return stat.S_IMODE(file_stat.st_mode) == mode and file_stat.st_uid == uid
  
  
  def safe_open(path, mode="w", chmod=None, buffering=None):
      """Safely open a file.
  
      :param str path: Path to a file.
      :param str mode: Same os `mode` for `open`.
      :param int chmod: Same as `mode` for `os.open`, uses Python defaults
          if ``None``.
      :param int buffering: Same as `bufsize` for `os.fdopen`, uses Python
          defaults if ``None``.
  
      """
      # pylint: disable=star-args
      open_args = () if chmod is None else (chmod,)
      fdopen_args = () if buffering is None else (buffering,)
      return os.fdopen(
          os.open(path, os.O_CREAT | os.O_EXCL | os.O_RDWR, *open_args),
          mode, *fdopen_args)
  
  
  def _unique_file(path, filename_pat, count, mode):
      while True:
          current_path = os.path.join(path, filename_pat(count))
          try:
              return safe_open(current_path, chmod=mode), current_path
          except OSError as err:
              # "File exists," is okay, try a different name.
              if err.errno != errno.EEXIST:
                  raise
          count += 1
  
  
  def unique_file(path, mode=0o777):
      """Safely finds a unique file.
  
      :param str path: path/filename.ext
      :param int mode: File mode
  
      :returns: tuple of file object and file name
  
      """
      path, tail = os.path.split(path)
      return _unique_file(
          path, filename_pat=(lambda count: "%04d_%s" % (count, tail)),
          count=0, mode=mode)
  
  
  def unique_lineage_name(path, filename, mode=0o777):
      """Safely finds a unique file using lineage convention.
  
      :param str path: directory path
      :param str filename: proposed filename
      :param int mode: file mode
  
      :returns: tuple of file object and file name (which may be modified
          from the requested one by appending digits to ensure uniqueness)
  
      :raises OSError: if writing files fails for an unanticipated reason,
          such as a full disk or a lack of permission to write to
          specified location.
  
      """
      preferred_path = os.path.join(path, "%s.conf" % (filename))
      try:
          return safe_open(preferred_path, chmod=mode), preferred_path
      except OSError as err:
          if err.errno != errno.EEXIST:
              raise
      return _unique_file(
          path, filename_pat=(lambda count: "%s-%04d.conf" % (filename, count)),
          count=1, mode=mode)
  
  
  def safely_remove(path):
      """Remove a file that may not exist."""
      try:
          os.remove(path)
      except OSError as err:
          if err.errno != errno.ENOENT:
              raise
  
  
  # Just make sure we don't get pwned... Make sure that it also doesn't
  # start with a period or have two consecutive periods <- this needs to
  # be done in addition to the regex
  EMAIL_REGEX = re.compile("[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+$")
  
  
  def safe_email(email):
      """Scrub email address before using it."""
      if EMAIL_REGEX.match(email) is not None:
          return not email.startswith(".") and ".." not in email
      else:
          logger.warn("Invalid email address: %s.", email)
          return False
  