Source code for certbot.compat.misc

"""
This compat module handles various platform specific calls that do not fall into one
particular category.
"""
from __future__ import absolute_import

import logging
import select
import subprocess
import sys
from typing import Optional
from typing import Tuple

from certbot import errors
from certbot.compat import os

try:
    from pywintypes import error as pywinerror
    from win32com.shell import shell as shellwin32
    from win32console import GetStdHandle
    from win32console import STD_OUTPUT_HANDLE
    POSIX_MODE = False
except ImportError:  # pragma: no cover
    POSIX_MODE = True


logger = logging.getLogger(__name__)

# For Linux: define OS specific standard binary directories
STANDARD_BINARY_DIRS = ["/usr/sbin", "/usr/local/bin", "/usr/local/sbin"] if POSIX_MODE else []


def raise_for_non_administrative_windows_rights() -> None:
    """
    On Windows, raise if current shell does not have the administrative rights.
    Do nothing on Linux.

    :raises .errors.Error: If the current shell does not have administrative rights on Windows.
    """
    if not POSIX_MODE and shellwin32.IsUserAnAdmin() == 0:  # pragma: no cover
        raise errors.Error('Error, certbot must be run on a shell with administrative rights.')


def prepare_virtual_console() -> None:
    """
    On Windows, ensure that Console Virtual Terminal Sequences are enabled.

    """
    if POSIX_MODE:
        return

    # https://docs.microsoft.com/en-us/windows/console/setconsolemode
    ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004

    # stdout/stderr will be the same console screen buffer, but this could return None or raise
    try:
        h = GetStdHandle(STD_OUTPUT_HANDLE)
        if h:
            h.SetConsoleMode(h.GetConsoleMode() | ENABLE_VIRTUAL_TERMINAL_PROCESSING)
    except pywinerror:
        logger.debug("Failed to set console mode", exc_info=True)


def readline_with_timeout(timeout: float, prompt: Optional[str]) -> str:
    """
    Read user input to return the first line entered, or raise after specified timeout.

    :param float timeout: The timeout in seconds given to the user.
    :param str prompt: The prompt message to display to the user.

    :returns: The first line entered by the user.
    :rtype: str

    """
    try:
        # Linux specific
        #
        # Call to select can only be done like this on UNIX
        rlist, _, _ = select.select([sys.stdin], [], [], timeout)
        if not rlist:
            raise errors.Error(
                "Timed out waiting for answer to prompt '{0}'".format(prompt if prompt else ""))
        return rlist[0].readline()
    except OSError:
        # Windows specific
        #
        # No way with select to make a timeout to the user input on Windows,
        # as select only supports socket in this case.
        # So no timeout on Windows for now.
        return sys.stdin.readline()


WINDOWS_DEFAULT_FOLDERS = {
    'config': 'C:\\Certbot',
    'work': 'C:\\Certbot\\lib',
    'logs': 'C:\\Certbot\\log',
}
LINUX_DEFAULT_FOLDERS = {
    'config': '/etc/letsencrypt',
    'work': '/var/lib/letsencrypt',
    'logs': '/var/log/letsencrypt',
}


def get_default_folder(folder_type: str) -> str:
    """
    Return the relevant default folder for the current OS

    :param str folder_type: The type of folder to retrieve (config, work or logs)

    :returns: The relevant default folder.
    :rtype: str

    """
    if os.name != 'nt':
        # Linux specific
        return LINUX_DEFAULT_FOLDERS[folder_type]
    # Windows specific
    return WINDOWS_DEFAULT_FOLDERS[folder_type]


def underscores_for_unsupported_characters_in_path(path: str) -> str:
    """
    Replace unsupported characters in path for current OS by underscores.
    :param str path: the path to normalize
    :return: the normalized path
    :rtype: str
    """
    if os.name != 'nt':
        # Linux specific
        return path

    # Windows specific
    drive, tail = os.path.splitdrive(path)
    return drive + tail.replace(':', '_')


def execute_command_status(cmd_name: str, shell_cmd: str,
                           env: Optional[dict] = None) -> Tuple[int, str, str]:
    """
    Run a command:
        - on Linux command will be run by the standard shell selected with
          subprocess.run(shell=True)
        - on Windows command will be run in a Powershell shell

    This function returns the exit code, and does not log the result and output
    of the command.

    :param str cmd_name: the user facing name of the hook being run
    :param str shell_cmd: shell command to execute
    :param dict env: environ to pass into subprocess.run

    :returns: `tuple` (`int` returncode, `str` stderr, `str` stdout)
    """
    logger.info("Running %s command: %s", cmd_name, shell_cmd)

    if POSIX_MODE:
        proc = subprocess.run(shell_cmd, shell=True, stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE, universal_newlines=True,
                              check=False, env=env)
    else:
        line = ['powershell.exe', '-Command', shell_cmd]
        proc = subprocess.run(line, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                              universal_newlines=True, check=False, env=env)

    # universal_newlines causes stdout and stderr to be str objects instead of
    # bytes in Python 3
    out, err = proc.stdout, proc.stderr
    return proc.returncode, err, out