~ubuntu-core-dev/unattended-upgrades/ubuntu

#!/usr/bin/python3
# Copyright (c) 2005-2012 Canonical Ltd
#
# AUTHOR:
# Michael Vogt <mvo@ubuntu.com>
#
# This file is part of unattended-upgrades
#
# unattended-upgrades is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation; either version 2 of the License, or (at
# your option) any later version.
#
# unattended-upgrades is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with unattended-upgrades; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
import apt_inst
import apt_pkg

import copy
import datetime
import email.charset
import fcntl
import re
import os
import string
import sys

from io import StringIO
from email.message import Message
from optparse import OptionParser

from subprocess import (
    Popen,
    PIPE,
    )

import apt
import logging
import lsb_release
import signal
import subprocess

import gettext
from gettext import gettext as _

# the reboot required flag file used by packages
REBOOT_REQUIRED_FILE = "/var/run/reboot-required"
MAIL_BINARY = "/usr/bin/mail"
SENDMAIL_BINARY = "/usr/sbin/sendmail"
DISTRO_CODENAME = lsb_release.get_distro_information()['CODENAME']
DISTRO_ID = lsb_release.get_distro_information()['ID']

# progress information is written here
PROGRESS_LOG = "/var/run/unattended-upgrades.progress"

# set from the sigint signal handler
SIGNAL_STOP_REQUEST = False


class UnknownMatcherError(ValueError):
    pass


class UnattendedUpgradesCache(apt.Cache):

    def __init__(self, rootdir, allowed_origins):
        apt.Cache.__init__(self, rootdir=rootdir)
        self.allowed_origins = allowed_origins
        # ensure we update the candidate versions
        self.adjust_candidate_versions()

    def clear(self):
        apt.Cache.clear(self)
        # ensure we update the candidate versions
        self.adjust_candidate_versions()

    def adjust_candidate_versions(self):
        """ Adjust candidate versions to match highest allowed origin

            This adjusts the origin even if the candidate has a higher
            version
        """
        for pkg in self:
            # important! this avoids downgrades below
            if not pkg.is_upgradable:
                continue
            # check if the candidate is already pointing to a allowed
            # origin and if so, do not mess with it
            if is_allowed_origin(pkg.candidate, self.allowed_origins):
                continue
            # check if we have a version in a allowed origin that is
            # not the candidate
            new_cand = None
            for ver in pkg.versions:
                # ignore versions that the user marked with priority < 0
                # (and ensure we have a python-apt that supports this)
                if hasattr(ver, "policy_priority") and ver.policy_priority < 0:
                    logging.debug("ignoring ver '%s' with priority < 0" % ver)
                    continue
                if is_allowed_origin(ver, self.allowed_origins):
                    # leave as soon as we have the highest new candidate
                    new_cand = ver
                    break
            if new_cand and new_cand != pkg.candidate:
                logging.debug("adjusting candidate version: '%s'" % new_cand)
                pkg.candidate = new_cand


class LogInstallProgress(apt.progress.base.InstallProgress):
    """ Install progress that writes to self.LOG
        (/var/run/unattended-upgrades.progress by default)
    """

    LOG = PROGRESS_LOG

    def status_change(self, pkg, percent, status):
        with open(self.LOG, "w") as f:
            f.write(_("Progress: %s %% (%s)") % (percent, pkg))

    def _fixup_fds(self):
        required_fds = [0, 1, 2,  # stdin, stdout, stderr
                        self.writefd,
                        self.write_stream.fileno(),
                        self.statusfd,
                        self.status_stream.fileno()
                        ]
        # ensure that our required fds close on exec
        for fd in required_fds[3:]:
            old_flags = fcntl.fcntl(fd, fcntl.F_GETFD)
            fcntl.fcntl(fd, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC)
        # close all fds
        proc_fd = "/proc/self/fd"
        if os.path.exists(proc_fd):
            error_count = 0
            for fdname in os.listdir(proc_fd):
                try:
                    fd = int(fdname)
                except Exception as e:
                    print("ERROR: can not get fd for '%s'" % fdname)
                if fd in required_fds:
                    continue
                try:
                    os.close(fd)
                    #print("closed: ", fd)
                except OSError as e:
                    # there will be one fd that can not be closed
                    # as its the fd from pythons internal diropen()
                    # so its ok to ignore one close error
                    error_count += 1
                    if error_count > 1:
                        print("ERROR: os.close(%s): %s" % (fd, e))

    def fork(self):
        pid = os.fork()
        if pid == 0:
            self._fixup_fds()
        return pid


class Unlocked:
    """
    Context manager for unlocking the apt lock while cache.commit() is run
    """

    def __enter__(self):
        try:
            apt_pkg.pkgsystem_unlock()
        except:
            pass

    def __exit__(self, exc_type, exc_value, exc_tb):
        try:
            apt_pkg.pkgsystem_unlock()
        except:
            pass


def is_dpkg_journal_dirty():
    """
    Return True if the dpkg journal is dirty
    (similar to debSystem::CheckUpdates)
    """
    d = os.path.join(
        os.path.dirname(apt_pkg.config.find_file("Dir::State::status")),
        "updates")
    for f in os.listdir(d):
        if re.match("[0-9]+", f):
            return True
    return False


def signal_handler(signal, frame):
    logging.warn("SIGUSR1 recieved, will stop")
    global SIGNAL_STOP_REQUEST
    SIGNAL_STOP_REQUEST = True


def substitute(line):
    """ substitude known mappings and return a new string

    Currently supported ${distro-release}
    """
    mapping = {"distro_codename": get_distro_codename(),
               "distro_id": get_distro_id(),
              }
    return string.Template(line).substitute(mapping)


def get_distro_codename():
    return DISTRO_CODENAME


def get_distro_id():
    return DISTRO_ID


def get_allowed_origins_legacy():
    """ legacy support for old Allowed-Origins var """
    allowed_origins = []
    for s in apt_pkg.config.value_list("Unattended-Upgrade::Allowed-Origins"):
        # if there is a ":" use that as seperator, else use spaces
        if ":" in s:
            (distro_id, distro_codename) = s.split(':')
        else:
            (distro_id, distro_codename) = s.split()
        # escape "," (see LP: #824856) - i wonder if there is a simpler way?
        distro_id = re.sub(r'([^\\]),', r'\1\\,', distro_id)
        distro_codename = re.sub(r'([^\\]),', r'\1\\,', distro_codename)
        # convert to new format
        allowed_origins.append("o=%s,a=%s" % (substitute(distro_id),
                                              substitute(distro_codename)))
    return allowed_origins


def get_allowed_origins():
    """ return a list of allowed origins from apt.conf

    This will take substitutions (like distro_id) into account.
    """
    allowed_origins = get_allowed_origins_legacy()
    for s in apt_pkg.config.value_list("Unattended-Upgrade::Origins-Pattern"):
        allowed_origins.append(substitute(s))
    return allowed_origins


def match_whitelist_string(whitelist, origin):
    """
    take a whitelist string in the form "origin=Debian,label=Debian-Security"
    and match against the given python-apt origin. A empty whitelist string
    never matches anything.
    """
    whitelist = whitelist.strip()
    if whitelist == "":
        logging.warn("empty match string matches nothing")
        return False
    res = True
    # make "\," the html quote equivalent
    whitelist = whitelist.replace("\,", "%2C")
    for token in whitelist.split(","):
        # strip and unquote the "," back
        (what, value) = [s.strip().replace("%2C", ",")
                         for s in token.split("=")]
        #logging.debug("matching '%s'='%s' against '%s'" % (
        #              what, value, origin))
        # first char is apt-cache policy output, send is the name
        # in the Release file
        if what in ("o", "origin"):
            res &= (value == origin.origin)
        elif what in ("l", "label"):
            res &= (value == origin.label)
        elif what in ("a", "suite", "archive"):
            res &= (value == origin.archive)
        elif what in ("c", "component"):
            res &= (value == origin.component)
        elif what in ("site",):
            res &= (value == origin.site)
        else:
            raise UnknownMatcherError(
                "Unknown whitelist entry for macher '%s' (token '%s')" % (
                    what, token))
    return res


def upgrade_normal(cache, pkgs_to_upgrade, logfile_dpkg):
    error = None
    res = False
    iprogress = LogInstallProgress()
    try:
        with Unlocked():
            res = cache.commit(install_progress=iprogress)
    except SystemError as e:
        error = e
    if res:
        logging.info(_("All upgrades installed"))
    else:
        logging.error(_("Installing the upgrades failed!"))
        logging.error(_("error message: '%s'") % error)
        logging.error(_("dpkg returned a error! See '%s' for details") %
                          logfile_dpkg)
    return res


def upgrade_in_minimal_steps(cache, pkgs_to_upgrade, logfile_dpkg, blacklist):

    install_log = LogInstallProgress()
    install_log.LOG += ".minimal-steps"

    # setup signal handler
    signal.signal(signal.SIGUSR1, signal_handler)

    # double check any changes we do
    allowed_origins = get_allowed_origins()

    # to upgrade contains the package names
    to_upgrade = set(pkgs_to_upgrade)
    while True:
        # find smallest set
        smallest_partition = to_upgrade
        for pkgname in to_upgrade:
            if SIGNAL_STOP_REQUEST:
                logging.warn("SIGNAL recieved, stopping")
                return True
            pkg = cache[pkgname]
            if pkg.is_upgradable:
                pkg.mark_upgrade()
            elif not pkg.is_installed:
                pkg.mark_install()
            else:
                continue
            # double check that we are not running into side effects like
            # what could have been caused LP: #1020680
            if not check_changes_for_sanity(cache, allowed_origins, blacklist):
                logging.error(
                    "Internal error while building a minimal partition."
                    "Cache has not allowed changes")
                return False
            changes = [pkg.name for pkg in cache.get_changes()]
            if len(changes) == 1:
                logging.debug("found leaf package %s" % pkg.name)
                smallest_partition = changes
                break
            if len(changes) < len(smallest_partition):
                logging.debug("found  partition of size %s (%s)" % (
                        len(changes), changes))
                smallest_partition = changes
            cache.clear()

        # write progress log information
        if len(pkgs_to_upgrade) > 0:
            percent = ((len(pkgs_to_upgrade) - len(to_upgrade)) /
                       float(len(pkgs_to_upgrade)) * 100.0)
        else:
            percent = 100.0
        install_log.status_change(pkg=",".join(smallest_partition),
                                  percent=percent,
                                  status="")
        # apply changes
        logging.debug("applying set %s" % smallest_partition)
        rewind_cache(cache, [cache[name] for name in smallest_partition])

        try:
            iprogress = LogInstallProgress()
            with Unlocked():
                res = cache.commit(install_progress=iprogress)
                if not res:
                    raise Exception("cache.commit() returned false")
            cache.open()
        except Exception as e:
            logging.error(_("Installing the upgrades failed!"))
            logging.error(_("error message: '%s'") % e)
            logging.error(_("dpkg returned a error! See '%s' for details") %
                              logfile_dpkg)
            return False
        to_upgrade = to_upgrade - set(smallest_partition)
        logging.debug("left to upgrade %s" % to_upgrade)
        if len(to_upgrade) == 0:
            logging.info(_("All upgrades installed"))
            break
    return True


def is_allowed_origin(ver, allowed_origins):
    if not ver:
        return False
    for origin in ver.origins:
        for allowed in allowed_origins:
            if match_whitelist_string(allowed, origin):
                return True
    return False


def is_pkgname_in_blacklist(pkgname, blacklist):
    for blacklist_regexp in blacklist:
        if re.match(blacklist_regexp, pkgname):
            logging.debug("skipping blacklisted package '%s'" % pkgname)
            return True
    return False


def check_changes_for_sanity(cache, allowed_origins, blacklist):
    if cache._depcache.broken_count != 0:
        return False
    for pkg in cache:
        if pkg.marked_delete:
            logging.debug("pkg '%s' now marked delete" % pkg.name)
            return False
        if pkg.marked_install or pkg.marked_upgrade:
            if not is_allowed_origin(pkg.candidate, allowed_origins):
                logging.debug("pkg '%s' not in allowed origin" % pkg.name)
                return False
            if is_pkgname_in_blacklist(pkg.name, blacklist):
                return False
            if pkg._pkg.selected_state == apt_pkg.SELSTATE_HOLD:
                logging.debug("pkg '%s' is on hold" % pkg.name)
                return False
            # check if the package is unsafe to upgrade unattended
            ignore_require_restart = apt_pkg.config.find_b(
                "Unattended-Upgrade::IgnoreAppsRequireRestart", False)
            if (pkg.marked_upgrade and
                ignore_require_restart is False and
                pkg.candidate.record.get("Upgrade-Requires") == "app-restart"):
                logging.debug("pkg '%s' requires app-restart, not safe to "
                              "upgrade unattended")
                return False
    return True


def pkgname_from_deb(debfile):
    # FIXME: add error checking here
    try:
        control = apt_inst.DebFile(debfile).control.extractdata("control")
        sections = apt_pkg.TagSection(control)
        return sections["Package"]
    except (IOError, SystemError) as e:
        logging.error("failed to read deb file '%s' (%s)" % (debfile, e))
        # dumb fallback
        return debfile.split("_")[0]


def get_md5sum_for_file_in_deb(deb_file, conf_file):
    dpkg_cmd = ["dpkg-deb", "--fsys-tarfile", deb_file]
    tar_cmd = ["tar", "-x", "-O", "-f", "-", "." + conf_file]
    md5_cmd = ["md5sum"]
    dpkg_p = Popen(dpkg_cmd, stdout=PIPE)
    tar_p = Popen(tar_cmd, stdin=dpkg_p.stdout, stdout=PIPE,
                  universal_newlines=True)
    md5_p = Popen(md5_cmd, stdin=tar_p.stdout, stdout=PIPE,
                  universal_newlines=True)
    pkg_md5sum = md5_p.communicate()[0].split()[0]
    return pkg_md5sum


# prefix is *only* needed for the build-in tests
def conffile_prompt(destFile, prefix=""):
    logging.debug("check_conffile_prompt('%s')" % destFile)
    pkgname = pkgname_from_deb(destFile)

    # get the conffiles for the /var/lib/dpkg/status file
    status_file = apt_pkg.config.find("Dir::State::status")
    tagfile = apt_pkg.TagFile(open(status_file, "r"))
    conffiles = ""
    for section in tagfile:
        if section.get("Package") == pkgname:
            logging.debug("found pkg: %s" % pkgname)
            if "Conffiles" in section:
                conffiles = section.get("Conffiles")
                break

    # get conffile value from pkg, its ok if the new version
    # does not have conffiles anymore
    pkg_conffiles = ""
    deb = apt_inst.DebFile(destFile)
    try:
        pkg_conffiles = deb.control.extractdata("conffiles").strip().decode(
            "utf-8")
    except LookupError as e:
        logging.debug("No conffiles in deb '%s' (%s)" % (destFile, e))

    # Conffiles:
    #  /etc/bash_completion.d/m-a c7780fab6b14d75ca54e11e992a6c11c
    dpkg_status_conffiles = {}
    for line in conffiles.splitlines():
        # ignore empty lines
        line = line.strip()
        if not line:
            continue
        # show what we do
        logging.debug("conffile line: '%s'", line)
        l = line.split()
        conf_file = l[0]
        md5 = l[1]
        if len(l) > 2:
            obs = l[2]
        else:
            obs = None
        # ignore if conffile is obsolete or does not exist
        if obs == "obsolete" or not os.path.exists(prefix + conf_file):
            continue
        # ignore state "newconffile" until its clearer if there
        # might be a dpkg prompt (LP: #936870)
        if md5 == "newconffile":
            continue
        if (not pkg_conffiles or
            not conf_file in pkg_conffiles.split("\n")):
            logging.debug("'%s' not in package conffiles '%s'" % (
                    conf_file, pkg_conffiles))
            continue
        # record for later
        dpkg_status_conffiles[conf_file] = md5
        # test against the installed file
        with open(prefix + conf_file, 'rb') as fb:
            current_md5 = apt_pkg.md5sum(fb)
        logging.debug("current md5: %s" % current_md5)
        # hashes are the same, no conffile prompt
        if current_md5 == md5:
            continue
        # calculate md5sum from the deb (may take a bit)
        pkg_md5sum = get_md5sum_for_file_in_deb(destFile, conf_file)
        logging.debug("pkg_md5sum: %s" % pkg_md5sum)
        # the md5sum in the deb is unchanged, this will not
        # trigger a conffile prompt
        if pkg_md5sum == md5:
            continue
        # if we made it to this point:
        #  current_md5 != pkg_md5sum != md5
        # and that will trigger a conffile prompt, we can
        # stop processing at this point and just return True
        return True

    # now check if there are conffiles in the pkg that where not there
    # in the previous version in the dpkg status file
    if pkg_conffiles:
        for conf_file in pkg_conffiles.split("\n"):
            if (not conf_file in dpkg_status_conffiles and
                os.path.exists(prefix + conf_file)):
                logging.debug("found conffile '%s' in new pkg but on dpkg "
                              "status" % conf_file)
                pkg_md5sum = get_md5sum_for_file_in_deb(destFile, conf_file)
                with open(prefix + conf_file, 'rb') as fp:
                    if pkg_md5sum != apt_pkg.md5sum(fp):
                        return True
    return False


def dpkg_conffile_prompt():
    if not "DPkg::Options" in apt_pkg.config:
        return True
    options = apt_pkg.config.value_list("DPkg::Options")
    for option in options:
        option = option.strip()
        if option in ["--force-confold", "--force-confnew"]:
            return False
    return True


def rewind_cache(cache, pkgs_to_upgrade):
    " set the cache back to the state with packages_to_upgrade "
    cache.clear()
    for pkg2 in pkgs_to_upgrade:
        pkg2.mark_upgrade()


def host():
    return os.uname()[1]


# *sigh* textwrap is nice, but it breaks "linux-image" into two
# seperate lines
def wrap(t, width=70, subsequent_indent=""):
    out = ""
    for s in t.split():
        if (len(out) - out.rfind("\n")) + len(s) > width:
            out += "\n" + subsequent_indent
        out += s + " "
    return out


def setup_apt_listchanges(conf="/etc/apt/listchanges.conf"):
    """ deal with apt-listchanges """
    # apt-listchanges will always send a mail if there is a mail address
    # set in the config regardless of the frontend used, so set it to
    # mail if we have a sendmail and to none if not (as it appears to
    # not check if sendmail is there or not), debian bug #579733
    if os.path.exists(SENDMAIL_BINARY):
        os.environ["APT_LISTCHANGES_FRONTEND"] = "mail"
    else:
        os.environ["APT_LISTCHANGES_FRONTEND"] = "none"


def _send_mail_using_mailx(to_address, subject, body):
    mail = subprocess.Popen(
        [MAIL_BINARY, "-s", subject, to_address],
        stdin=subprocess.PIPE,  universal_newlines=True)
    mail.stdin.write(body)
    mail.stdin.close()
    ret = mail.wait()
    return ret


def _send_mail_using_sendmail(to_address, subject, body):
    # format as a proper mail
    msg = Message()
    charset = email.charset.Charset("utf-8")
    charset.body_encoding = email.charset.QP
    msg.set_charset(charset)
    msg.set_payload(body)
    msg['Subject'] = subject
    msg['To'] = to_address
    sendmail = subprocess.Popen(
        [SENDMAIL_BINARY, "-oi", "-t"],
        stdin=subprocess.PIPE, universal_newlines=True)
    sendmail.stdin.write(msg.as_string())
    sendmail.stdin.close()
    ret = sendmail.wait()
    return ret


def send_summary_mail(pkgs, res, pkgs_kept_back, mem_log, logfile_dpkg):
    " send mail (if configured in Unattended-Upgrade::Mail) "
    to_email = apt_pkg.config.find("Unattended-Upgrade::Mail", "")
    if not to_email:
        return
    # FIXME: this should say that sendmail works too but doing that no
    #        would break translations
    if not os.path.exists(MAIL_BINARY) and not os.path.exists(SENDMAIL_BINARY):
        logging.error(_("No '/usr/bin/mail', can not send mail. "
                        "You probably want to install the 'mailx' package."))
        return
    # if the operation was successful and the user has requested to get
    # mails on on errors, just exit here
    if (res and
        apt_pkg.config.find_b("Unattended-Upgrade::MailOnlyOnError", False)):
        return
    # Check if reboot-required flag is present
    logging.debug("Sending mail with '%s' to '%s'" % (logfile_dpkg, to_email))
    if os.path.isfile(REBOOT_REQUIRED_FILE):
        subject = _(
            "[reboot required] unattended-upgrades result for '%s'") % host()
    else:
        subject = _("unattended-upgrades result for '%s'") % host()
    body = _("Unattended upgrade returned: %s\n\n") % res
    if os.path.isfile(REBOOT_REQUIRED_FILE):
        body += _(
            "Warning: A reboot is required to complete this upgrade.\n\n")
    body += _("Packages that are upgraded:\n")
    body += " " + wrap(pkgs, 70, " ")
    body += "\n"
    if pkgs_kept_back:
        body += _("Packages with upgradable origin but kept back:\n")
        body += " " + wrap(" ".join(pkgs_kept_back), 70, " ")
        body += "\n"
    body += "\n"
    if os.path.exists(logfile_dpkg):
        body += _("Package installation log:") + "\n"
        with open(logfile_dpkg) as fp:
            body += fp.read()
        body += "\n\n"
    body += _("Unattended-upgrades log:\n")
    body += mem_log.getvalue()

    # python2 needs this as utf8 encoded string (not unicode)
    if sys.version < '3':
        body = body.encode("utf-8")

    if os.path.exists(SENDMAIL_BINARY):
        ret = _send_mail_using_sendmail(to_email, subject, body)
    elif os.path.exists(MAIL_BINARY):
        ret = _send_mail_using_mailx(to_email, subject, body)
    else:
        raise AssertionError(
            "This should never be reached, if we are here we either "
            "have sendmail or mailx. Please report this as a bug.")
    logging.debug("mail returned: %s" % ret)


def do_install(cache, pkgs_to_upgrade, blacklisted_pkgs, options,
               logfile_dpkg):
    # set debconf to NON_INTERACTIVE, redirect output
    os.putenv("DEBIAN_FRONTEND", "noninteractive")
    setup_apt_listchanges()

    # redirect to log
    REDIRECT_INPUT = os.devnull
    fd = os.open(REDIRECT_INPUT, os.O_RDWR)
    os.dup2(fd, 0)

    logging.info(_("Writing dpkg log to '%s'") % logfile_dpkg)

    # do not create log in dry-run mode, just output to stdout/stderr
    if options.dry_run:
        old_stdout = 1
        old_stderr = 2
    else:
        fd = os.open(logfile_dpkg, os.O_RDWR | os.O_CREAT, 0o644)
        old_stdout = os.dup(1)
        old_stderr = os.dup(2)
        os.dup2(fd, 1)
        os.dup2(fd, 2)

    try:
        if (options.minimal_upgrade_steps or
            # COMPAT with the mispelling
            apt_pkg.config.find_b(
                "Unattended-Upgrades::MinimalSteps", False) or
            apt_pkg.config.find_b(
                "Unattended-Upgrade::MinimalSteps", False)):
            with open("/var/run/unattended-upgrades.pid", "w") as fp:
                fp.write("%s" % os.getpid())
            # try upgrade all "pkgs" in minimal steps
            pkg_install_success = upgrade_in_minimal_steps(
                cache, [pkg.name for pkg in pkgs_to_upgrade], logfile_dpkg,
                blacklisted_pkgs)
        else:
            pkg_install_success = upgrade_normal(
                cache, [pkg.name for pkg in pkgs_to_upgrade], logfile_dpkg)
    except Exception as e:
        # print unhandled exceptions here this way, while stderr is redirected
        os.write(old_stderr, "Exception: %s" % e)

    # restore
    os.dup2(old_stdout, 1)
    os.dup2(old_stderr, 2)

    return pkg_install_success


def _setup_alternative_rootdir(rootdir):
    # clear system unattended-upgrade stuff
    apt_pkg.config.clear("Unattended-Upgrade")
    # read rootdir (taken from apt.Cache, but we need to run it
    # here before the cache gets initialized
    if os.path.exists(rootdir + "/etc/apt/apt.conf"):
        apt_pkg.read_config_file(apt_pkg.config,
                                 rootdir + "/etc/apt/apt.conf")
    if os.path.isdir(rootdir + "/etc/apt/apt.conf.d"):
        apt_pkg.read_config_dir(apt_pkg.config,
                                rootdir + "/etc/apt/apt.conf.d")


def _get_logdir():
    logdir = apt_pkg.config.find_dir(
        "Unattended-Upgrade::LogDir",
        # COMPAT only
        apt_pkg.config.find_dir("APT::UnattendedUpgrades::LogDir",
                                "/var/log/unattended-upgrades/"))
    return logdir


def _setup_logging(options):
    # ensure this is run only once
    if len(logging.root.handlers) > 0:
        return

    # init the logging
    logdir = _get_logdir()
    logfile = os.path.join(
        logdir,
        apt_pkg.config.find(
            "Unattended-Upgrade::LogFile",
            # COMPAT only
            apt_pkg.config.find("APT::UnattendedUpgrades::LogFile",
                                "unattended-upgrades.log")))

    if not options.dry_run and not os.path.exists(logdir):
        os.makedirs(logdir)

    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s %(levelname)s %(message)s',
                        filename=logfile)
    # additional logging
    logger = logging.getLogger()
    mem_log = StringIO()
    if options.debug:
        logger.setLevel(logging.DEBUG)
        stdout_handler = logging.StreamHandler(sys.stdout)
        logger.addHandler(stdout_handler)
    if apt_pkg.config.find("Unattended-Upgrade::Mail", ""):
        mem_log_handler = logging.StreamHandler(mem_log)
        logger.addHandler(mem_log_handler)
    return mem_log


def get_blacklisted_pkgs():
    return apt_pkg.config.value_list("Unattended-Upgrade::Package-Blacklist")


def main(options, rootdir=""):

    # useful for testing
    if rootdir:
        _setup_alternative_rootdir(rootdir)

    # setup logging
    mem_log = _setup_logging(options)

    # format (origin, archive), e.g. ("Ubuntu","dapper-security")
    allowed_origins = get_allowed_origins()

    # pkgs that are (for some reason) not save to install
    blacklisted_pkgs = get_blacklisted_pkgs()
    logging.info(_("Initial blacklisted packages: %s"),
                 " ".join(blacklisted_pkgs))
    logging.info(_("Starting unattended upgrades script"))

    # display available origin
    logging.info(_("Allowed origins are: %s") % allowed_origins)

    # check if the journal is dirty and if so, take emergceny action
    # the alternative is to leave the system potentially unsecure until
    # the user comes in and fixes
    if (is_dpkg_journal_dirty() and
        apt_pkg.config.find_b(
            "Unattended-Upgrade::AutoFixInterruptedDpkg", True)):
        # ensure the dpkg database is not already locked (LP: #754330)
        admindir = os.path.dirname(apt_pkg.config.find("Dir::State::Status"))
        lockfd = apt_pkg.get_lock(os.path.join(admindir, "lock"), False)
        if lockfd > 0:
            logging.warning(
                _("Unclean dpkg state detected, trying to correct"))
            print(_("Unclean dpkg state detected, trying to correct"))
            env = copy.copy(os.environ)
            env["DEBIAN_FRONTEND"] = "noninteractive"
            try:
                os.close(lockfd)
                output = subprocess.check_output(
                    ["dpkg", "--force-confold", "--configure", "-a"], env=env)
            except subprocess.CalledProcessError as e:
                output = e.output
            logging.warning(_("dpkg --configure -a output:\n%s" % output))
        else:
            logging.debug("Unclean dpkg state, but locked, another package "
                          "manager working?")

    # check and get lock
    try:
        apt_pkg.pkgsystem_lock()
    except SystemError as e:
        logging.error(_("Lock could not be acquired (another package "
                        "manager running?)"))
        print(_("Cache lock can not be acquired, exiting"))
        sys.exit(1)

    # get a cache
    cache = UnattendedUpgradesCache(rootdir=rootdir,
                                    allowed_origins=allowed_origins)
    if cache._depcache.broken_count > 0:
        print(_("Cache has broken packages, exiting"))
        logging.error(_("Cache has broken packages, exiting"))
        sys.exit(1)
    # speed things up with latest apt
    actiongroup = apt_pkg.ActionGroup(cache._depcache)
    actiongroup  # pyflakes

    # find out about the packages that are upgradable (in a allowed_origin)
    pkgs_to_upgrade = []
    pkgs_kept_back = []
    pkgs_auto_removable = set([pkg.name for pkg in cache
                               if pkg.is_auto_removable])

    # now do the actual upgrade
    for pkg in cache:
        if options.debug and pkg.is_upgradable:
            logging.debug("Checking: %s (%s)" % (
                    pkg.name, map(str, getattr(pkg.candidate, "origins", []))))
        if (pkg.is_upgradable and
            not is_pkgname_in_blacklist(pkg.name, blacklisted_pkgs) and
            is_allowed_origin(pkg.candidate, allowed_origins)):
            try:
                pkg.mark_upgrade()
                if check_changes_for_sanity(cache, allowed_origins,
                                            blacklisted_pkgs):
                    # add to packages to upgrade
                    pkgs_to_upgrade.append(pkg)
                    # re-eval pkgs_kept_back as the resolver may fail to
                    # directly upgrade a pkg, but that may work during
                    # a subsequent operation, see debian bug #639840
                    for pkgname in pkgs_kept_back:
                        if (cache[pkgname].marked_install or
                            cache[pkgname].marked_upgrade):
                            pkgs_kept_back.remove(pkgname)
                            pkgs_to_upgrade.append(cache[pkgname])
                else:
                    logging.debug("sanity check failed")
                    rewind_cache(cache, pkgs_to_upgrade)
                    pkgs_kept_back.append(pkg.name)
            except SystemError as e:
                # can't upgrade
                logging.warning(
                    _("package '%s' upgradable but fails to "
                      "be marked for upgrade (%s)") % (pkg.name, e))
                rewind_cache(cache, pkgs_to_upgrade)
                pkgs_kept_back.append(pkg.name)

    pkgs_to_upgrade.sort(key=lambda p: p.name)
    pkgs = "\n".join([pkg.name for pkg in pkgs_to_upgrade])
    logging.debug("pkgs that look like they should be upgraded: %s" % pkgs)

    # download what looks good
    if options.debug:
        fetcher = apt_pkg.Acquire(apt.progress.text.AcquireProgress())
    else:
        fetcher = apt_pkg.Acquire()
    list = apt_pkg.SourceList()
    list.read_main_list()
    recs = cache._records
    pm = apt_pkg.PackageManager(cache._depcache)
    try:
        pm.get_archives(fetcher, list, recs)
    except SystemError as e:
        logging.error(_("GetArchives() failed: '%s'") % e)
    res = fetcher.run()
    logging.debug("fetch.run() result: %s" % res)

    if dpkg_conffile_prompt():
        # now check the downloaded debs for conffile conflicts and build
        # a blacklist
        for item in fetcher.items:
            logging.debug("%s" % item)
            if item.status == item.STAT_ERROR:
                print(_("An error ocured: '%s'") % item.error_text)
                logging.error(_("An error ocured: '%s'") % item.error_text)
            if not item.complete:
                print(_("The URI '%s' failed to download, aborting") %
                      item.desc_uri)
                logging.error(_("The URI '%s' failed to download, aborting") %
                              item.desc_uri)
                sys.exit(1)
            if not os.path.exists(item.destfile):
                print(_("Download finished, but file '%s' not there?!?" %
                        item.destfile))
                logging.error("Download finished, but file '%s' not "
                              "there?!?" % item.destfile)
                sys.exit(1)
            if not item.is_trusted:
                blacklisted_pkgs.append(pkgname_from_deb(item.destfile))
            if conffile_prompt(item.destfile):
                # skip package (means to re-run the whole marking again
                # and making sure that the package will not be pulled in by
                # some other package again!)
                #
                # print to stdout to ensure that this message is part of
                # the cron mail (only if no summary mail is requested)
                email = apt_pkg.config.find("Unattended-Upgrade::Mail", "")
                if not email:
                    print(_("Package '%s' has conffile prompt and needs "
                            "to be upgraded manually") % pkgname_from_deb(
                            item.destfile))
                # log to the logfile
                logging.warning(_("Package '%s' has conffile prompt and "
                                  "needs to be upgraded manually") %
                                pkgname_from_deb(item.destfile))
                blacklisted_pkgs.append(pkgname_from_deb(item.destfile))
                pkgs_kept_back.append(pkgname_from_deb(item.destfile))

        # redo the selection about the packages to upgrade based on the new
        # blacklist
        logging.debug("blacklist: %s" % blacklisted_pkgs)
        # find out about the packages that are upgradable (in a allowed_origin)
        if len(blacklisted_pkgs) > 0:
            cache.clear()
            old_pkgs_to_upgrade = pkgs_to_upgrade[:]
            pkgs_to_upgrade = []
            for pkg in old_pkgs_to_upgrade:
                logging.debug("Checking (blacklist): %s" % (pkg.name))
                pkg.mark_upgrade()
                if check_changes_for_sanity(cache, allowed_origins,
                                            blacklisted_pkgs):
                    pkgs_to_upgrade.append(pkg)
                else:
                    if not (pkg.name in pkgs_kept_back):
                        pkgs_kept_back.append(pkg.name)
                    logging.info(_("package '%s' not upgraded") % pkg.name)
                    cache.clear()
                    for pkg2 in pkgs_to_upgrade:
                        pkg2.mark_upgrade()
    else:
        logging.debug("dpkg is configured not to cause conffile prompts")

    # do auto-remove
    if apt_pkg.config.find_b(
        "Unattended-Upgrade::Remove-Unused-Dependencies", False):
        now_auto_removable = set([pkg.name for pkg in cache
                               if pkg.is_auto_removable])
        for pkgname in now_auto_removable - pkgs_auto_removable:
            logging.debug("marking %s for remove" % pkgname)
            cache[pkgname].mark_delete()
        logging.info(_("Packages that are auto removed: '%s'") %
                     " ".join(now_auto_removable - pkgs_auto_removable))

    logging.debug("InstCount=%i DelCount=%i BrokenCount=%i" % (
            cache._depcache.inst_count, cache._depcache.del_count,
            cache._depcache.broken_count))

    # exit if there is nothing to do and nothing to report
    if (len(pkgs_to_upgrade) == 0) and (len(pkgs_kept_back) == 0):
        logging.info(_("No packages found that can be upgraded unattended"))
        return

    # check if its configured for install on shutdown, if so, the
    # environment UNATTENDED_UPGRADES_FORCE_INSTALL_ON_SHUTDOWN will
    # be set by the unatteded-upgrades-shutdown script
    if (not "UNATTENDED_UPGRADES_FORCE_INSTALL_ON_SHUTDOWN" in os.environ and
        apt_pkg.config.find_b("Unattended-Upgrade::InstallOnShutdown", False)):
        logger = logging.getLogger()
        logger.debug("Configured to install on shutdown, so exiting now")
        return

    # check if we are in dry-run mode
    if options.dry_run:
        logging.info("Option --dry-run given, *not* performing real actions")
        apt_pkg.config.set("Debug::pkgDPkgPM", "1")

    # do the install based on the new list of pkgs
    pkgs = " ".join([pkg.name for pkg in pkgs_to_upgrade])
    logging.info(_("Packages that are upgraded: %s" % pkgs))

    # get log
    now = datetime.datetime.now()
    logfile_dpkg = os.path.join(
        _get_logdir(), 'unattended-upgrades-dpkg_%s.log' % now.isoformat('_'))

    # only perform install step if we actually have packages to install
    pkg_install_success = None
    shutdown_lock = -1
    if len(pkgs_to_upgrade) > 0:
        # lock for the shutdown check - its fine if the system
        # is shutdown while downloading but not so much while installing
        shutdown_lock = apt_pkg.get_lock("/var/run/unattended-upgrades.lock")
        # do install
        pkg_install_success = do_install(
            cache, pkgs_to_upgrade, blacklisted_pkgs, options, logfile_dpkg)

    # send a mail (if needed)
    if not options.dry_run:
        send_summary_mail(
            pkgs, pkg_install_success, pkgs_kept_back, mem_log, logfile_dpkg)

    # auto-reboot (if required and the config for this is set
    if (apt_pkg.config.find_b(
            "Unattended-Upgrade::Automatic-Reboot", False) and
        os.path.exists(REBOOT_REQUIRED_FILE)):
        if shutdown_lock > 0:
            os.close(shutdown_lock)
        logging.warning("Found %s, rebooting" % REBOOT_REQUIRED_FILE)
        subprocess.call(["/sbin/reboot"])


if __name__ == "__main__":
    localesApp = "unattended-upgrades"
    localesDir = "/usr/share/locale"
    gettext.bindtextdomain(localesApp, localesDir)
    gettext.textdomain(localesApp)

    # init the options
    parser = OptionParser()
    parser.add_option("-d", "--debug",
                      action="store_true", dest="debug", default=False,
                      help=_("print debug messages"))
    parser.add_option("", "--dry-run",
                      action="store_true", default=False,
                      help=_("Simulation, download but do not install"))
    parser.add_option("", "--minimal_upgrade_steps",
                      action="store_true", default=False,
                      help=_("Upgrade in minimal steps (and allow "
                             "interrupting with SIGINT"))
    (options, args) = parser.parse_args()

    if os.getuid() != 0:
        print(_("You need to be root to run this application"))
        sys.exit(1)

    # nice & ionce
    os.nice(19)
    IONICE = "/usr/bin/ionice"
    if os.path.exists(IONICE):
        with open(os.devnull, "w") as fstderr:
            subprocess.call([IONICE, "-c3", "-p", str(os.getpid())],
                            stderr=fstderr)

    # ensure that we are not killed when the terminal goes away e.g. on
    # shutdown
    signal.signal(signal.SIGHUP, signal.SIG_IGN)

    # run the main code
    main(options)