Add option `--download-sections` to download video partially

[yt-dlp.git] / yt_dlp / cookies.py

import contextlib
import ctypes
import json
import os
import shutil
import struct
import subprocess
import sys
import tempfile
import time
from datetime import datetime, timedelta, timezone
from enum import Enum, auto
from hashlib import pbkdf2_hmac

from .aes import (
    aes_cbc_decrypt_bytes,
    aes_gcm_decrypt_and_verify_bytes,
    unpad_pkcs7,
)
from .compat import compat_b64decode, compat_cookiejar_Cookie
from .dependencies import (
    _SECRETSTORAGE_UNAVAILABLE_REASON,
    secretstorage,
    sqlite3,
)
from .minicurses import MultilinePrinter, QuietMultilinePrinter
from .utils import Popen, YoutubeDLCookieJar, error_to_str, expand_path

CHROMIUM_BASED_BROWSERS = {'brave', 'chrome', 'chromium', 'edge', 'opera', 'vivaldi'}
SUPPORTED_BROWSERS = CHROMIUM_BASED_BROWSERS | {'firefox', 'safari'}


class YDLLogger:
    def __init__(self, ydl=None):
        self._ydl = ydl

    def debug(self, message):
        if self._ydl:
            self._ydl.write_debug(message)

    def info(self, message):
        if self._ydl:
            self._ydl.to_screen(f'[Cookies] {message}')

    def warning(self, message, only_once=False):
        if self._ydl:
            self._ydl.report_warning(message, only_once)

    def error(self, message):
        if self._ydl:
            self._ydl.report_error(message)

    class ProgressBar(MultilinePrinter):
        _DELAY, _timer = 0.1, 0

        def print(self, message):
            if time.time() - self._timer > self._DELAY:
                self.print_at_line(f'[Cookies] {message}', 0)
                self._timer = time.time()

    def progress_bar(self):
        """Return a context manager with a print method. (Optional)"""
        # Do not print to files/pipes, loggers, or when --no-progress is used
        if not self._ydl or self._ydl.params.get('noprogress') or self._ydl.params.get('logger'):
            return
        file = self._ydl._out_files.error
        try:
            if not file.isatty():
                return
        except BaseException:
            return
        return self.ProgressBar(file, preserve_output=False)


def _create_progress_bar(logger):
    if hasattr(logger, 'progress_bar'):
        printer = logger.progress_bar()
        if printer:
            return printer
    printer = QuietMultilinePrinter()
    printer.print = lambda _: None
    return printer


def load_cookies(cookie_file, browser_specification, ydl):
    cookie_jars = []
    if browser_specification is not None:
        browser_name, profile, keyring = _parse_browser_specification(*browser_specification)
        cookie_jars.append(extract_cookies_from_browser(browser_name, profile, YDLLogger(ydl), keyring=keyring))

    if cookie_file is not None:
        is_filename = YoutubeDLCookieJar.is_path(cookie_file)
        if is_filename:
            cookie_file = expand_path(cookie_file)

        jar = YoutubeDLCookieJar(cookie_file)
        if not is_filename or os.access(cookie_file, os.R_OK):
            jar.load(ignore_discard=True, ignore_expires=True)
        cookie_jars.append(jar)

    return _merge_cookie_jars(cookie_jars)


def extract_cookies_from_browser(browser_name, profile=None, logger=YDLLogger(), *, keyring=None):
    if browser_name == 'firefox':
        return _extract_firefox_cookies(profile, logger)
    elif browser_name == 'safari':
        return _extract_safari_cookies(profile, logger)
    elif browser_name in CHROMIUM_BASED_BROWSERS:
        return _extract_chrome_cookies(browser_name, profile, keyring, logger)
    else:
        raise ValueError(f'unknown browser: {browser_name}')


def _extract_firefox_cookies(profile, logger):
    logger.info('Extracting cookies from firefox')
    if not sqlite3:
        logger.warning('Cannot extract cookies from firefox without sqlite3 support. '
                       'Please use a python interpreter compiled with sqlite3 support')
        return YoutubeDLCookieJar()

    if profile is None:
        search_root = _firefox_browser_dir()
    elif _is_path(profile):
        search_root = profile
    else:
        search_root = os.path.join(_firefox_browser_dir(), profile)

    cookie_database_path = _find_most_recently_used_file(search_root, 'cookies.sqlite', logger)
    if cookie_database_path is None:
        raise FileNotFoundError(f'could not find firefox cookies database in {search_root}')
    logger.debug(f'Extracting cookies from: "{cookie_database_path}"')

    with tempfile.TemporaryDirectory(prefix='yt_dlp') as tmpdir:
        cursor = None
        try:
            cursor = _open_database_copy(cookie_database_path, tmpdir)
            cursor.execute('SELECT host, name, value, path, expiry, isSecure FROM moz_cookies')
            jar = YoutubeDLCookieJar()
            with _create_progress_bar(logger) as progress_bar:
                table = cursor.fetchall()
                total_cookie_count = len(table)
                for i, (host, name, value, path, expiry, is_secure) in enumerate(table):
                    progress_bar.print(f'Loading cookie {i: 6d}/{total_cookie_count: 6d}')
                    cookie = compat_cookiejar_Cookie(
                        version=0, name=name, value=value, port=None, port_specified=False,
                        domain=host, domain_specified=bool(host), domain_initial_dot=host.startswith('.'),
                        path=path, path_specified=bool(path), secure=is_secure, expires=expiry, discard=False,
                        comment=None, comment_url=None, rest={})
                    jar.set_cookie(cookie)
            logger.info(f'Extracted {len(jar)} cookies from firefox')
            return jar
        finally:
            if cursor is not None:
                cursor.connection.close()


def _firefox_browser_dir():
    if sys.platform in ('linux', 'linux2'):
        return os.path.expanduser('~/.mozilla/firefox')
    elif sys.platform == 'win32':
        return os.path.expandvars(R'%APPDATA%\Mozilla\Firefox\Profiles')
    elif sys.platform == 'darwin':
        return os.path.expanduser('~/Library/Application Support/Firefox')
    else:
        raise ValueError(f'unsupported platform: {sys.platform}')


def _get_chromium_based_browser_settings(browser_name):
    # https://chromium.googlesource.com/chromium/src/+/HEAD/docs/user_data_dir.md
    if sys.platform in ('linux', 'linux2'):
        config = _config_home()
        browser_dir = {
            'brave': os.path.join(config, 'BraveSoftware/Brave-Browser'),
            'chrome': os.path.join(config, 'google-chrome'),
            'chromium': os.path.join(config, 'chromium'),
            'edge': os.path.join(config, 'microsoft-edge'),
            'opera': os.path.join(config, 'opera'),
            'vivaldi': os.path.join(config, 'vivaldi'),
        }[browser_name]

    elif sys.platform == 'win32':
        appdata_local = os.path.expandvars('%LOCALAPPDATA%')
        appdata_roaming = os.path.expandvars('%APPDATA%')
        browser_dir = {
            'brave': os.path.join(appdata_local, R'BraveSoftware\Brave-Browser\User Data'),
            'chrome': os.path.join(appdata_local, R'Google\Chrome\User Data'),
            'chromium': os.path.join(appdata_local, R'Chromium\User Data'),
            'edge': os.path.join(appdata_local, R'Microsoft\Edge\User Data'),
            'opera': os.path.join(appdata_roaming, R'Opera Software\Opera Stable'),
            'vivaldi': os.path.join(appdata_local, R'Vivaldi\User Data'),
        }[browser_name]

    elif sys.platform == 'darwin':
        appdata = os.path.expanduser('~/Library/Application Support')
        browser_dir = {
            'brave': os.path.join(appdata, 'BraveSoftware/Brave-Browser'),
            'chrome': os.path.join(appdata, 'Google/Chrome'),
            'chromium': os.path.join(appdata, 'Chromium'),
            'edge': os.path.join(appdata, 'Microsoft Edge'),
            'opera': os.path.join(appdata, 'com.operasoftware.Opera'),
            'vivaldi': os.path.join(appdata, 'Vivaldi'),
        }[browser_name]

    else:
        raise ValueError(f'unsupported platform: {sys.platform}')

    # Linux keyring names can be determined by snooping on dbus while opening the browser in KDE:
    # dbus-monitor "interface='org.kde.KWallet'" "type=method_return"
    keyring_name = {
        'brave': 'Brave',
        'chrome': 'Chrome',
        'chromium': 'Chromium',
        'edge': 'Microsoft Edge' if sys.platform == 'darwin' else 'Chromium',
        'opera': 'Opera' if sys.platform == 'darwin' else 'Chromium',
        'vivaldi': 'Vivaldi' if sys.platform == 'darwin' else 'Chrome',
    }[browser_name]

    browsers_without_profiles = {'opera'}

    return {
        'browser_dir': browser_dir,
        'keyring_name': keyring_name,
        'supports_profiles': browser_name not in browsers_without_profiles
    }


def _extract_chrome_cookies(browser_name, profile, keyring, logger):
    logger.info(f'Extracting cookies from {browser_name}')

    if not sqlite3:
        logger.warning(f'Cannot extract cookies from {browser_name} without sqlite3 support. '
                       'Please use a python interpreter compiled with sqlite3 support')
        return YoutubeDLCookieJar()

    config = _get_chromium_based_browser_settings(browser_name)

    if profile is None:
        search_root = config['browser_dir']
    elif _is_path(profile):
        search_root = profile
        config['browser_dir'] = os.path.dirname(profile) if config['supports_profiles'] else profile
    else:
        if config['supports_profiles']:
            search_root = os.path.join(config['browser_dir'], profile)
        else:
            logger.error(f'{browser_name} does not support profiles')
            search_root = config['browser_dir']

    cookie_database_path = _find_most_recently_used_file(search_root, 'Cookies', logger)
    if cookie_database_path is None:
        raise FileNotFoundError(f'could not find {browser_name} cookies database in "{search_root}"')
    logger.debug(f'Extracting cookies from: "{cookie_database_path}"')

    decryptor = get_cookie_decryptor(config['browser_dir'], config['keyring_name'], logger, keyring=keyring)

    with tempfile.TemporaryDirectory(prefix='yt_dlp') as tmpdir:
        cursor = None
        try:
            cursor = _open_database_copy(cookie_database_path, tmpdir)
            cursor.connection.text_factory = bytes
            column_names = _get_column_names(cursor, 'cookies')
            secure_column = 'is_secure' if 'is_secure' in column_names else 'secure'
            cursor.execute(f'SELECT host_key, name, value, encrypted_value, path, expires_utc, {secure_column} FROM cookies')
            jar = YoutubeDLCookieJar()
            failed_cookies = 0
            unencrypted_cookies = 0
            with _create_progress_bar(logger) as progress_bar:
                table = cursor.fetchall()
                total_cookie_count = len(table)
                for i, line in enumerate(table):
                    progress_bar.print(f'Loading cookie {i: 6d}/{total_cookie_count: 6d}')
                    is_encrypted, cookie = _process_chrome_cookie(decryptor, *line)
                    if not cookie:
                        failed_cookies += 1
                        continue
                    elif not is_encrypted:
                        unencrypted_cookies += 1
                    jar.set_cookie(cookie)
            if failed_cookies > 0:
                failed_message = f' ({failed_cookies} could not be decrypted)'
            else:
                failed_message = ''
            logger.info(f'Extracted {len(jar)} cookies from {browser_name}{failed_message}')
            counts = decryptor._cookie_counts.copy()
            counts['unencrypted'] = unencrypted_cookies
            logger.debug(f'cookie version breakdown: {counts}')
            return jar
        finally:
            if cursor is not None:
                cursor.connection.close()


def _process_chrome_cookie(decryptor, host_key, name, value, encrypted_value, path, expires_utc, is_secure):
    host_key = host_key.decode()
    name = name.decode()
    value = value.decode()
    path = path.decode()
    is_encrypted = not value and encrypted_value

    if is_encrypted:
        value = decryptor.decrypt(encrypted_value)
        if value is None:
            return is_encrypted, None

    return is_encrypted, compat_cookiejar_Cookie(
        version=0, name=name, value=value, port=None, port_specified=False,
        domain=host_key, domain_specified=bool(host_key), domain_initial_dot=host_key.startswith('.'),
        path=path, path_specified=bool(path), secure=is_secure, expires=expires_utc, discard=False,
        comment=None, comment_url=None, rest={})


class ChromeCookieDecryptor:
    """
    Overview:

        Linux:
        - cookies are either v10 or v11
            - v10: AES-CBC encrypted with a fixed key
            - v11: AES-CBC encrypted with an OS protected key (keyring)
            - v11 keys can be stored in various places depending on the activate desktop environment [2]

        Mac:
        - cookies are either v10 or not v10
            - v10: AES-CBC encrypted with an OS protected key (keyring) and more key derivation iterations than linux
            - not v10: 'old data' stored as plaintext

        Windows:
        - cookies are either v10 or not v10
            - v10: AES-GCM encrypted with a key which is encrypted with DPAPI
            - not v10: encrypted with DPAPI

    Sources:
    - [1] https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/
    - [2] https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/key_storage_linux.cc
        - KeyStorageLinux::CreateService
    """

    _cookie_counts = {}

    def decrypt(self, encrypted_value):
        raise NotImplementedError('Must be implemented by sub classes')


def get_cookie_decryptor(browser_root, browser_keyring_name, logger, *, keyring=None):
    if sys.platform in ('linux', 'linux2'):
        return LinuxChromeCookieDecryptor(browser_keyring_name, logger, keyring=keyring)
    elif sys.platform == 'darwin':
        return MacChromeCookieDecryptor(browser_keyring_name, logger)
    elif sys.platform == 'win32':
        return WindowsChromeCookieDecryptor(browser_root, logger)
    else:
        raise NotImplementedError(f'Chrome cookie decryption is not supported on this platform: {sys.platform}')


class LinuxChromeCookieDecryptor(ChromeCookieDecryptor):
    def __init__(self, browser_keyring_name, logger, *, keyring=None):
        self._logger = logger
        self._v10_key = self.derive_key(b'peanuts')
        password = _get_linux_keyring_password(browser_keyring_name, keyring, logger)
        self._v11_key = None if password is None else self.derive_key(password)
        self._cookie_counts = {'v10': 0, 'v11': 0, 'other': 0}

    @staticmethod
    def derive_key(password):
        # values from
        # https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/os_crypt_linux.cc
        return pbkdf2_sha1(password, salt=b'saltysalt', iterations=1, key_length=16)

    def decrypt(self, encrypted_value):
        version = encrypted_value[:3]
        ciphertext = encrypted_value[3:]

        if version == b'v10':
            self._cookie_counts['v10'] += 1
            return _decrypt_aes_cbc(ciphertext, self._v10_key, self._logger)

        elif version == b'v11':
            self._cookie_counts['v11'] += 1
            if self._v11_key is None:
                self._logger.warning('cannot decrypt v11 cookies: no key found', only_once=True)
                return None
            return _decrypt_aes_cbc(ciphertext, self._v11_key, self._logger)

        else:
            self._cookie_counts['other'] += 1
            return None


class MacChromeCookieDecryptor(ChromeCookieDecryptor):
    def __init__(self, browser_keyring_name, logger):
        self._logger = logger
        password = _get_mac_keyring_password(browser_keyring_name, logger)
        self._v10_key = None if password is None else self.derive_key(password)
        self._cookie_counts = {'v10': 0, 'other': 0}

    @staticmethod
    def derive_key(password):
        # values from
        # https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/os_crypt_mac.mm
        return pbkdf2_sha1(password, salt=b'saltysalt', iterations=1003, key_length=16)

    def decrypt(self, encrypted_value):
        version = encrypted_value[:3]
        ciphertext = encrypted_value[3:]

        if version == b'v10':
            self._cookie_counts['v10'] += 1
            if self._v10_key is None:
                self._logger.warning('cannot decrypt v10 cookies: no key found', only_once=True)
                return None

            return _decrypt_aes_cbc(ciphertext, self._v10_key, self._logger)

        else:
            self._cookie_counts['other'] += 1
            # other prefixes are considered 'old data' which were stored as plaintext
            # https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/os_crypt_mac.mm
            return encrypted_value


class WindowsChromeCookieDecryptor(ChromeCookieDecryptor):
    def __init__(self, browser_root, logger):
        self._logger = logger
        self._v10_key = _get_windows_v10_key(browser_root, logger)
        self._cookie_counts = {'v10': 0, 'other': 0}

    def decrypt(self, encrypted_value):
        version = encrypted_value[:3]
        ciphertext = encrypted_value[3:]

        if version == b'v10':
            self._cookie_counts['v10'] += 1
            if self._v10_key is None:
                self._logger.warning('cannot decrypt v10 cookies: no key found', only_once=True)
                return None

            # https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/os_crypt_win.cc
            #   kNonceLength
            nonce_length = 96 // 8
            # boringssl
            #   EVP_AEAD_AES_GCM_TAG_LEN
            authentication_tag_length = 16

            raw_ciphertext = ciphertext
            nonce = raw_ciphertext[:nonce_length]
            ciphertext = raw_ciphertext[nonce_length:-authentication_tag_length]
            authentication_tag = raw_ciphertext[-authentication_tag_length:]

            return _decrypt_aes_gcm(ciphertext, self._v10_key, nonce, authentication_tag, self._logger)

        else:
            self._cookie_counts['other'] += 1
            # any other prefix means the data is DPAPI encrypted
            # https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/os_crypt_win.cc
            return _decrypt_windows_dpapi(encrypted_value, self._logger).decode()


def _extract_safari_cookies(profile, logger):
    if profile is not None:
        logger.error('safari does not support profiles')
    if sys.platform != 'darwin':
        raise ValueError(f'unsupported platform: {sys.platform}')

    cookies_path = os.path.expanduser('~/Library/Cookies/Cookies.binarycookies')

    if not os.path.isfile(cookies_path):
        logger.debug('Trying secondary cookie location')
        cookies_path = os.path.expanduser('~/Library/Containers/com.apple.Safari/Data/Library/Cookies/Cookies.binarycookies')
        if not os.path.isfile(cookies_path):
            raise FileNotFoundError('could not find safari cookies database')

    with open(cookies_path, 'rb') as f:
        cookies_data = f.read()

    jar = parse_safari_cookies(cookies_data, logger=logger)
    logger.info(f'Extracted {len(jar)} cookies from safari')
    return jar


class ParserError(Exception):
    pass


class DataParser:
    def __init__(self, data, logger):
        self._data = data
        self.cursor = 0
        self._logger = logger

    def read_bytes(self, num_bytes):
        if num_bytes < 0:
            raise ParserError(f'invalid read of {num_bytes} bytes')
        end = self.cursor + num_bytes
        if end > len(self._data):
            raise ParserError('reached end of input')
        data = self._data[self.cursor:end]
        self.cursor = end
        return data

    def expect_bytes(self, expected_value, message):
        value = self.read_bytes(len(expected_value))
        if value != expected_value:
            raise ParserError(f'unexpected value: {value} != {expected_value} ({message})')

    def read_uint(self, big_endian=False):
        data_format = '>I' if big_endian else '<I'
        return struct.unpack(data_format, self.read_bytes(4))[0]

    def read_double(self, big_endian=False):
        data_format = '>d' if big_endian else '<d'
        return struct.unpack(data_format, self.read_bytes(8))[0]

    def read_cstring(self):
        buffer = []
        while True:
            c = self.read_bytes(1)
            if c == b'\x00':
                return b''.join(buffer).decode()
            else:
                buffer.append(c)

    def skip(self, num_bytes, description='unknown'):
        if num_bytes > 0:
            self._logger.debug(f'skipping {num_bytes} bytes ({description}): {self.read_bytes(num_bytes)!r}')
        elif num_bytes < 0:
            raise ParserError(f'invalid skip of {num_bytes} bytes')

    def skip_to(self, offset, description='unknown'):
        self.skip(offset - self.cursor, description)

    def skip_to_end(self, description='unknown'):
        self.skip_to(len(self._data), description)


def _mac_absolute_time_to_posix(timestamp):
    return int((datetime(2001, 1, 1, 0, 0, tzinfo=timezone.utc) + timedelta(seconds=timestamp)).timestamp())


def _parse_safari_cookies_header(data, logger):
    p = DataParser(data, logger)
    p.expect_bytes(b'cook', 'database signature')
    number_of_pages = p.read_uint(big_endian=True)
    page_sizes = [p.read_uint(big_endian=True) for _ in range(number_of_pages)]
    return page_sizes, p.cursor


def _parse_safari_cookies_page(data, jar, logger):
    p = DataParser(data, logger)
    p.expect_bytes(b'\x00\x00\x01\x00', 'page signature')
    number_of_cookies = p.read_uint()
    record_offsets = [p.read_uint() for _ in range(number_of_cookies)]
    if number_of_cookies == 0:
        logger.debug(f'a cookies page of size {len(data)} has no cookies')
        return

    p.skip_to(record_offsets[0], 'unknown page header field')

    with _create_progress_bar(logger) as progress_bar:
        for i, record_offset in enumerate(record_offsets):
            progress_bar.print(f'Loading cookie {i: 6d}/{number_of_cookies: 6d}')
            p.skip_to(record_offset, 'space between records')
            record_length = _parse_safari_cookies_record(data[record_offset:], jar, logger)
            p.read_bytes(record_length)
    p.skip_to_end('space in between pages')


def _parse_safari_cookies_record(data, jar, logger):
    p = DataParser(data, logger)
    record_size = p.read_uint()
    p.skip(4, 'unknown record field 1')
    flags = p.read_uint()
    is_secure = bool(flags & 0x0001)
    p.skip(4, 'unknown record field 2')
    domain_offset = p.read_uint()
    name_offset = p.read_uint()
    path_offset = p.read_uint()
    value_offset = p.read_uint()
    p.skip(8, 'unknown record field 3')
    expiration_date = _mac_absolute_time_to_posix(p.read_double())
    _creation_date = _mac_absolute_time_to_posix(p.read_double())  # noqa: F841

    try:
        p.skip_to(domain_offset)
        domain = p.read_cstring()

        p.skip_to(name_offset)
        name = p.read_cstring()

        p.skip_to(path_offset)
        path = p.read_cstring()

        p.skip_to(value_offset)
        value = p.read_cstring()
    except UnicodeDecodeError:
        logger.warning('failed to parse Safari cookie because UTF-8 decoding failed', only_once=True)
        return record_size

    p.skip_to(record_size, 'space at the end of the record')

    cookie = compat_cookiejar_Cookie(
        version=0, name=name, value=value, port=None, port_specified=False,
        domain=domain, domain_specified=bool(domain), domain_initial_dot=domain.startswith('.'),
        path=path, path_specified=bool(path), secure=is_secure, expires=expiration_date, discard=False,
        comment=None, comment_url=None, rest={})
    jar.set_cookie(cookie)
    return record_size


def parse_safari_cookies(data, jar=None, logger=YDLLogger()):
    """
    References:
        - https://github.com/libyal/dtformats/blob/main/documentation/Safari%20Cookies.asciidoc
            - this data appears to be out of date but the important parts of the database structure is the same
            - there are a few bytes here and there which are skipped during parsing
    """
    if jar is None:
        jar = YoutubeDLCookieJar()
    page_sizes, body_start = _parse_safari_cookies_header(data, logger)
    p = DataParser(data[body_start:], logger)
    for page_size in page_sizes:
        _parse_safari_cookies_page(p.read_bytes(page_size), jar, logger)
    p.skip_to_end('footer')
    return jar


class _LinuxDesktopEnvironment(Enum):
    """
    https://chromium.googlesource.com/chromium/src/+/refs/heads/main/base/nix/xdg_util.h
    DesktopEnvironment
    """
    OTHER = auto()
    CINNAMON = auto()
    GNOME = auto()
    KDE = auto()
    PANTHEON = auto()
    UNITY = auto()
    XFCE = auto()


class _LinuxKeyring(Enum):
    """
    https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/key_storage_util_linux.h
    SelectedLinuxBackend
    """
    KWALLET = auto()
    GNOMEKEYRING = auto()
    BASICTEXT = auto()


SUPPORTED_KEYRINGS = _LinuxKeyring.__members__.keys()


def _get_linux_desktop_environment(env):
    """
    https://chromium.googlesource.com/chromium/src/+/refs/heads/main/base/nix/xdg_util.cc
    GetDesktopEnvironment
    """
    xdg_current_desktop = env.get('XDG_CURRENT_DESKTOP', None)
    desktop_session = env.get('DESKTOP_SESSION', None)
    if xdg_current_desktop is not None:
        xdg_current_desktop = xdg_current_desktop.split(':')[0].strip()

        if xdg_current_desktop == 'Unity':
            if desktop_session is not None and 'gnome-fallback' in desktop_session:
                return _LinuxDesktopEnvironment.GNOME
            else:
                return _LinuxDesktopEnvironment.UNITY
        elif xdg_current_desktop == 'GNOME':
            return _LinuxDesktopEnvironment.GNOME
        elif xdg_current_desktop == 'X-Cinnamon':
            return _LinuxDesktopEnvironment.CINNAMON
        elif xdg_current_desktop == 'KDE':
            return _LinuxDesktopEnvironment.KDE
        elif xdg_current_desktop == 'Pantheon':
            return _LinuxDesktopEnvironment.PANTHEON
        elif xdg_current_desktop == 'XFCE':
            return _LinuxDesktopEnvironment.XFCE
    elif desktop_session is not None:
        if desktop_session in ('mate', 'gnome'):
            return _LinuxDesktopEnvironment.GNOME
        elif 'kde' in desktop_session:
            return _LinuxDesktopEnvironment.KDE
        elif 'xfce' in desktop_session:
            return _LinuxDesktopEnvironment.XFCE
    else:
        if 'GNOME_DESKTOP_SESSION_ID' in env:
            return _LinuxDesktopEnvironment.GNOME
        elif 'KDE_FULL_SESSION' in env:
            return _LinuxDesktopEnvironment.KDE
    return _LinuxDesktopEnvironment.OTHER


def _choose_linux_keyring(logger):
    """
    https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/key_storage_util_linux.cc
    SelectBackend
    """
    desktop_environment = _get_linux_desktop_environment(os.environ)
    logger.debug(f'detected desktop environment: {desktop_environment.name}')
    if desktop_environment == _LinuxDesktopEnvironment.KDE:
        linux_keyring = _LinuxKeyring.KWALLET
    elif desktop_environment == _LinuxDesktopEnvironment.OTHER:
        linux_keyring = _LinuxKeyring.BASICTEXT
    else:
        linux_keyring = _LinuxKeyring.GNOMEKEYRING
    return linux_keyring


def _get_kwallet_network_wallet(logger):
    """ The name of the wallet used to store network passwords.

    https://chromium.googlesource.com/chromium/src/+/refs/heads/main/components/os_crypt/kwallet_dbus.cc
    KWalletDBus::NetworkWallet
    which does a dbus call to the following function:
    https://api.kde.org/frameworks/kwallet/html/classKWallet_1_1Wallet.html
    Wallet::NetworkWallet
    """
    default_wallet = 'kdewallet'
    try:
        proc = Popen([
            'dbus-send', '--session', '--print-reply=literal',
            '--dest=org.kde.kwalletd5',
            '/modules/kwalletd5',
            'org.kde.KWallet.networkWallet'
        ], stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)

        stdout, stderr = proc.communicate_or_kill()
        if proc.returncode != 0:
            logger.warning('failed to read NetworkWallet')
            return default_wallet
        else:
            network_wallet = stdout.decode().strip()
            logger.debug(f'NetworkWallet = "{network_wallet}"')
            return network_wallet
    except Exception as e:
        logger.warning(f'exception while obtaining NetworkWallet: {e}')
        return default_wallet


def _get_kwallet_password(browser_keyring_name, logger):
    logger.debug('using kwallet-query to obtain password from kwallet')

    if shutil.which('kwallet-query') is None:
        logger.error('kwallet-query command not found. KWallet and kwallet-query '
                     'must be installed to read from KWallet. kwallet-query should be'
                     'included in the kwallet package for your distribution')
        return b''

    network_wallet = _get_kwallet_network_wallet(logger)

    try:
        proc = Popen([
            'kwallet-query',
            '--read-password', f'{browser_keyring_name} Safe Storage',
            '--folder', f'{browser_keyring_name} Keys',
            network_wallet
        ], stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)

        stdout, stderr = proc.communicate_or_kill()
        if proc.returncode != 0:
            logger.error(f'kwallet-query failed with return code {proc.returncode}. Please consult '
                         'the kwallet-query man page for details')
            return b''
        else:
            if stdout.lower().startswith(b'failed to read'):
                logger.debug('failed to read password from kwallet. Using empty string instead')
                # this sometimes occurs in KDE because chrome does not check hasEntry and instead
                # just tries to read the value (which kwallet returns "") whereas kwallet-query
                # checks hasEntry. To verify this:
                # dbus-monitor "interface='org.kde.KWallet'" "type=method_return"
                # while starting chrome.
                # this may be a bug as the intended behaviour is to generate a random password and store
                # it, but that doesn't matter here.
                return b''
            else:
                logger.debug('password found')
                if stdout[-1:] == b'\n':
                    stdout = stdout[:-1]
                return stdout
    except Exception as e:
        logger.warning(f'exception running kwallet-query: {error_to_str(e)}')
        return b''


def _get_gnome_keyring_password(browser_keyring_name, logger):
    if not secretstorage:
        logger.error(f'secretstorage not available {_SECRETSTORAGE_UNAVAILABLE_REASON}')
        return b''
    # the Gnome keyring does not seem to organise keys in the same way as KWallet,
    # using `dbus-monitor` during startup, it can be observed that chromium lists all keys
    # and presumably searches for its key in the list. It appears that we must do the same.
    # https://github.com/jaraco/keyring/issues/556
    with contextlib.closing(secretstorage.dbus_init()) as con:
        col = secretstorage.get_default_collection(con)
        for item in col.get_all_items():
            if item.get_label() == f'{browser_keyring_name} Safe Storage':
                return item.get_secret()
        else:
            logger.error('failed to read from keyring')
            return b''


def _get_linux_keyring_password(browser_keyring_name, keyring, logger):
    # note: chrome/chromium can be run with the following flags to determine which keyring backend
    # it has chosen to use
    # chromium --enable-logging=stderr --v=1 2>&1 | grep key_storage_
    # Chromium supports a flag: --password-store=<basic|gnome|kwallet> so the automatic detection
    # will not be sufficient in all cases.

    keyring = _LinuxKeyring[keyring] if keyring else _choose_linux_keyring(logger)
    logger.debug(f'Chosen keyring: {keyring.name}')

    if keyring == _LinuxKeyring.KWALLET:
        return _get_kwallet_password(browser_keyring_name, logger)
    elif keyring == _LinuxKeyring.GNOMEKEYRING:
        return _get_gnome_keyring_password(browser_keyring_name, logger)
    elif keyring == _LinuxKeyring.BASICTEXT:
        # when basic text is chosen, all cookies are stored as v10 (so no keyring password is required)
        return None
    assert False, f'Unknown keyring {keyring}'


def _get_mac_keyring_password(browser_keyring_name, logger):
    logger.debug('using find-generic-password to obtain password from OSX keychain')
    try:
        proc = Popen(
            ['security', 'find-generic-password',
             '-w',  # write password to stdout
             '-a', browser_keyring_name,  # match 'account'
             '-s', f'{browser_keyring_name} Safe Storage'],  # match 'service'
            stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)

        stdout, stderr = proc.communicate_or_kill()
        if stdout[-1:] == b'\n':
            stdout = stdout[:-1]
        return stdout
    except Exception as e:
        logger.warning(f'exception running find-generic-password: {error_to_str(e)}')
        return None


def _get_windows_v10_key(browser_root, logger):
    path = _find_most_recently_used_file(browser_root, 'Local State', logger)
    if path is None:
        logger.error('could not find local state file')
        return None
    logger.debug(f'Found local state file at "{path}"')
    with open(path, encoding='utf8') as f:
        data = json.load(f)
    try:
        base64_key = data['os_crypt']['encrypted_key']
    except KeyError:
        logger.error('no encrypted key in Local State')
        return None
    encrypted_key = compat_b64decode(base64_key)
    prefix = b'DPAPI'
    if not encrypted_key.startswith(prefix):
        logger.error('invalid key')
        return None
    return _decrypt_windows_dpapi(encrypted_key[len(prefix):], logger)


def pbkdf2_sha1(password, salt, iterations, key_length):
    return pbkdf2_hmac('sha1', password, salt, iterations, key_length)


def _decrypt_aes_cbc(ciphertext, key, logger, initialization_vector=b' ' * 16):
    plaintext = unpad_pkcs7(aes_cbc_decrypt_bytes(ciphertext, key, initialization_vector))
    try:
        return plaintext.decode()
    except UnicodeDecodeError:
        logger.warning('failed to decrypt cookie (AES-CBC) because UTF-8 decoding failed. Possibly the key is wrong?', only_once=True)
        return None


def _decrypt_aes_gcm(ciphertext, key, nonce, authentication_tag, logger):
    try:
        plaintext = aes_gcm_decrypt_and_verify_bytes(ciphertext, key, authentication_tag, nonce)
    except ValueError:
        logger.warning('failed to decrypt cookie (AES-GCM) because the MAC check failed. Possibly the key is wrong?', only_once=True)
        return None

    try:
        return plaintext.decode()
    except UnicodeDecodeError:
        logger.warning('failed to decrypt cookie (AES-GCM) because UTF-8 decoding failed. Possibly the key is wrong?', only_once=True)
        return None


def _decrypt_windows_dpapi(ciphertext, logger):
    """
    References:
        - https://docs.microsoft.com/en-us/windows/win32/api/dpapi/nf-dpapi-cryptunprotectdata
    """
    from ctypes.wintypes import DWORD

    class DATA_BLOB(ctypes.Structure):
        _fields_ = [('cbData', DWORD),
                    ('pbData', ctypes.POINTER(ctypes.c_char))]

    buffer = ctypes.create_string_buffer(ciphertext)
    blob_in = DATA_BLOB(ctypes.sizeof(buffer), buffer)
    blob_out = DATA_BLOB()
    ret = ctypes.windll.crypt32.CryptUnprotectData(
        ctypes.byref(blob_in),  # pDataIn
        None,  # ppszDataDescr: human readable description of pDataIn
        None,  # pOptionalEntropy: salt?
        None,  # pvReserved: must be NULL
        None,  # pPromptStruct: information about prompts to display
        0,  # dwFlags
        ctypes.byref(blob_out)  # pDataOut
    )
    if not ret:
        logger.warning('failed to decrypt with DPAPI', only_once=True)
        return None

    result = ctypes.string_at(blob_out.pbData, blob_out.cbData)
    ctypes.windll.kernel32.LocalFree(blob_out.pbData)
    return result


def _config_home():
    return os.environ.get('XDG_CONFIG_HOME', os.path.expanduser('~/.config'))


def _open_database_copy(database_path, tmpdir):
    # cannot open sqlite databases if they are already in use (e.g. by the browser)
    database_copy_path = os.path.join(tmpdir, 'temporary.sqlite')
    shutil.copy(database_path, database_copy_path)
    conn = sqlite3.connect(database_copy_path)
    return conn.cursor()


def _get_column_names(cursor, table_name):
    table_info = cursor.execute(f'PRAGMA table_info({table_name})').fetchall()
    return [row[1].decode() for row in table_info]


def _find_most_recently_used_file(root, filename, logger):
    # if there are multiple browser profiles, take the most recently used one
    i, paths = 0, []
    with _create_progress_bar(logger) as progress_bar:
        for curr_root, dirs, files in os.walk(root):
            for file in files:
                i += 1
                progress_bar.print(f'Searching for "{filename}": {i: 6d} files searched')
                if file == filename:
                    paths.append(os.path.join(curr_root, file))
    return None if not paths else max(paths, key=lambda path: os.lstat(path).st_mtime)


def _merge_cookie_jars(jars):
    output_jar = YoutubeDLCookieJar()
    for jar in jars:
        for cookie in jar:
            output_jar.set_cookie(cookie)
        if jar.filename is not None:
            output_jar.filename = jar.filename
    return output_jar


def _is_path(value):
    return os.path.sep in value


def _parse_browser_specification(browser_name, profile=None, keyring=None):
    if browser_name not in SUPPORTED_BROWSERS:
        raise ValueError(f'unsupported browser: "{browser_name}"')
    if keyring not in (None, *SUPPORTED_KEYRINGS):
        raise ValueError(f'unsupported keyring: "{keyring}"')
    if profile is not None and _is_path(profile):
        profile = os.path.expanduser(profile)
    return browser_name, profile, keyring