#! /usr/bin/python
# Copyright 2011-2013  Lars Wirzenius
# Copyright 2012  Codethink Limited
# Copyright 2014 Neil Williams <codehelp@debian.org>
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

import cliapp
import crypt
import logging
import os
import re
import shutil
import subprocess
import tempfile
import time


__version__ = '0.7'

# pylint: disable=invalid-name


class VmDebootstrap(cliapp.Application):  # pylint: disable=too-many-public-methods

    def __init__(self, progname=None, version=__version__, description=None, epilog=None):
        super(VmDebootstrap, self).__init__(progname, version, description, epilog)
        self.remove_dirs = []
        self.mount_points = []

    def add_settings(self):
        default_arch = subprocess.check_output(
            ["dpkg", "--print-architecture"]).strip()

        self.settings.boolean(
            ['verbose'], 'report what is going on')
        self.settings.string(
            ['image'], 'put created disk image in FILE',
            metavar='FILE')
        self.settings.bytesize(
            ['size'],
            'create a disk image of size SIZE (%default)',
            metavar='SIZE',
            default='1G')
        self.settings.bytesize(
            ['bootsize'],
            'create boot partition of size SIZE (%default)',
            metavar='BOOTSIZE',
            default='0%')
        self.settings.string(
            ['boottype'],
            'specify file system type for /boot/',
            default='ext2')
        self.settings.bytesize(
            ['bootoffset'],
            'Space to leave at start of the image for bootloader',
            default='0')
        self.settings.string(
            ['part-type'],
            'Partition type to use for this image',
            default='msdos')
        self.settings.string(
            ['roottype'],
            'specify file system type for /',
            default='ext4')
        self.settings.bytesize(
            ['swap'],
            'create swap space of size SIZE (min 256Mb)')
        self.settings.string(
            ['foreign'],
            'set up foreign debootstrap environment using provided program (ie binfmt handler)')
        self.settings.string(
            ['variant'],
            'select debootstrap variant it not using the default')
        self.settings.boolean(
            ['extlinux'],
            'install extlinux?',
            default=True)
        self.settings.string(
            ['tarball'],
            "tar up the disk's contents in FILE",
            metavar='FILE')
        self.settings.string(
            ['apt-mirror'],
            'configure apt to use MIRROR',
            metavar='URL')
        self.settings.string(
            ['mirror'],
            'use MIRROR as package source (%default)',
            metavar='URL',
            default='http://http.debian.net/debian/')
        self.settings.string(
            ['arch'],
            'architecture to use (%default)',
            metavar='ARCH',
            default=default_arch)
        self.settings.string(
            ['distribution'],
            'release to use (%default)',
            metavar='NAME',
            default='stable')
        self.settings.string_list(
            ['package'],
            'install PACKAGE onto system')
        self.settings.string_list(
            ['custom-package'],
            'install package in DEB file onto system (not from mirror)',
            metavar='DEB')
        self.settings.boolean(
            ['no-kernel'],
            'do not install a linux package')
        self.settings.boolean(
            ['enable-dhcp'],
            'enable DHCP on eth0')
        self.settings.string(
            ['root-password'],
            'set root password',
            metavar='PASSWORD')
        self.settings.boolean(
            ['lock-root-password'],
            'lock root account so they cannot login?')
        self.settings.string(
            ['customize'],
            'run SCRIPT after setting up system',
            metavar='SCRIPT')
        self.settings.string(
            ['hostname'],
            'set name to HOSTNAME (%default)',
            metavar='HOSTNAME',
            default='debian')
        self.settings.string_list(
            ['user'],
            'create USER with PASSWORD',
            metavar='USER/PASSWORD')
        self.settings.boolean(
            ['serial-console'],
            'configure image to use a serial console')
        self.settings.string(
            ['serial-console-command'],
            'command to manage the serial console, appended to /etc/inittab (%default)',
            metavar='COMMAND',
            default='/sbin/getty -L ttyS0 115200 vt100')
        self.settings.boolean(
            ['sudo'],
            'install sudo, and if user is created, add them to sudo group')
        self.settings.string(
            ['owner'],
            'the user who will own the image when the build is complete.')
        self.settings.boolean(
            ['squash'],
            'use squashfs on the final image.')
        self.settings.boolean(
            ['configure-apt'],
            'Create an apt source based on the distribution and mirror selected.')
        self.settings.boolean(
            ['mbr'],
            'Run install-mbr (default if extlinux used)')
        self.settings.boolean(
            ['grub'],
            'Install and configure grub2 - disables extlinux.')
        self.settings.boolean(
            ['sparse'],
            'Do not fill the image with zeros to keep a sparse disk image',
            default=False)
        self.settings.boolean(
            ['pkglist'],
            'Create a list of package names included in the image.')

    def process_args(self, args):  # pylint: disable=too-many-branches,too-many-statements
        if not self.settings['image'] and not self.settings['tarball']:
            raise cliapp.AppException(
                'You must give disk image filename, or tarball filename')
        if self.settings['image'] and not self.settings['size']:
            raise cliapp.AppException(
                'If disk image is specified, you must give image size.')

        rootdir = None
        try:
            rootdev = None
            roottype = self.settings['roottype']
            bootdev = None
            boottype = None
            if self.settings['image']:
                self.create_empty_image()
                self.partition_image()
                if self.settings['mbr'] or self.settings['extlinux']:
                    self.install_mbr()
                (rootdev, bootdev, swapdev) = self.setup_kpartx()
                if self.settings['swap'] > 0:
                    self.message("Creating swap space")
                    self.runcmd(['mkswap', swapdev])
                self.mkfs(rootdev, fstype=roottype)
                rootdir = self.mount(rootdev)
                if bootdev:
                    if self.settings['boottype']:
                        boottype = self.settings['boottype']
                    else:
                        boottype = 'ext2'
                    self.mkfs(bootdev, fstype=boottype)
                    bootdir = '%s/%s' % (rootdir, 'boot/')
                    os.mkdir(bootdir)
                    self.mount(bootdev, bootdir)
            else:
                rootdir = self.mkdtemp()
            self.debootstrap(rootdir)
            self.set_hostname(rootdir)
            self.create_fstab(rootdir, rootdev, roottype, bootdev, boottype)
            self.install_debs(rootdir)
            self.cleanup_apt_cache(rootdir)
            self.set_root_password(rootdir)
            self.create_users(rootdir)
            self.remove_udev_persistent_rules(rootdir)
            self.setup_networking(rootdir)
            if self.settings['configure-apt'] or self.settings['apt-mirror']:
                self.configure_apt(rootdir)
            self.customize(rootdir)
            self.update_initramfs(rootdir)

            if self.settings['image']:
                if self.settings['grub']:
                    self.install_grub2(rootdev, rootdir)
                elif self.settings['extlinux']:
                    self.install_extlinux(rootdev, rootdir)
                self.append_serial_console(rootdir)
                self.optimize_image(rootdir)
                if self.settings['squash']:
                    self.squash()
            if self.settings['pkglist']:
                self.list_installed_pkgs(rootdir)

            if self.settings['foreign']:
                os.unlink('%s/usr/bin/%s' %
                          (rootdir, os.path.basename(self.settings['foreign'])))

            if self.settings['tarball']:
                self.create_tarball(rootdir)

            if self.settings['owner']:
                self.chown()
        except BaseException as e:
            self.message('EEEK! Something bad happened...')
            if rootdir:
                db_log = os.path.join(rootdir, 'debootstrap', 'debootstrap.log')
                if os.path.exists(db_log):
                    shutil.copy(db_log, os.getcwd())
            self.message(e)
            self.cleanup_system()
            raise
        else:
            self.cleanup_system()

    def message(self, msg):
        logging.info(msg)
        if self.settings['verbose']:
            print msg

    def runcmd(self, argv, stdin='', ignore_fail=False, env=None, **kwargs):
        logging.debug('runcmd: %s %s %s', argv, env, kwargs)
        p = subprocess.Popen(argv, stdin=subprocess.PIPE,
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                             env=env, **kwargs)
        out, err = p.communicate(stdin)
        if p.returncode != 0:
            msg = 'command failed: %s\n%s\n%s' % (argv, out, err)
            logging.error(msg)
            if not ignore_fail:
                raise cliapp.AppException(msg)
        return out

    def mkdtemp(self):
        dirname = tempfile.mkdtemp()
        self.remove_dirs.append(dirname)
        logging.debug('mkdir %s', dirname)
        return dirname

    def mount(self, device, path=None):
        if not path:
            mount_point = self.mkdtemp()
        else:
            mount_point = path
        self.message('Mounting %s on %s' % (device, mount_point))
        self.runcmd(['mount', device, mount_point])
        self.mount_points.append(mount_point)
        logging.debug('mounted %s on %s', device, mount_point)
        return mount_point

    def create_empty_image(self):
        self.message('Creating disk image')
        self.runcmd(['qemu-img', 'create', '-f', 'raw',
                     self.settings['image'],
                     str(self.settings['size'])])

    def partition_image(self):
        """
        Uses fat16 (msdos) partitioning by default, use part-type to change.
        If bootoffset is specified, the first actual partition
        starts at that offset to allow customisation scripts to
        put bootloader images into the space, e.g. u-boot.
        """
        self.message('Creating partitions')
        self.runcmd(['parted', '-s', self.settings['image'],
                     'mklabel', self.settings['part-type']])
        partoffset = 0
        bootsize = 0
        extent = '100%'
        swap = 256 * 1024 * 1024
        if self.settings['swap'] > 0:
            if self.settings['swap'] > swap:
                swap = self.settings['swap']
            else:
                # minimum 256Mb as default qemu ram is 128Mb
                logging.debug("Setting minimum 256Mb swap space")
            extent = "%s%%" % int(100 * (self.settings['size'] - swap) / self.settings['size'])
        if self.settings['bootoffset'] and self.settings['bootoffset'] is not '0':
            # turn v.small offsets into something at least possible to create.
            if self.settings['bootoffset'] < 1048576:
                partoffset = 1
                logging.info(
                    "Setting bootoffset %smib to allow for %s bytes",
                    partoffset, self.settings['bootoffset'])
            else:
                partoffset = self.settings['bootoffset'] / (1024 * 1024)
                self.message("Using bootoffset: %smib %s bytes" % (partoffset, self.settings['bootoffset']))
        if self.settings['bootsize'] and self.settings['bootsize'] is not '0%':
            bootsize = self.settings['bootsize'] / (1024 * 1024)
            bootsize += partoffset
            self.message("Using bootsize %smib: %s bytes" % (bootsize, self.settings['bootsize']))
            logging.debug("Starting boot partition at %sMb", bootsize)
            self.runcmd(['parted', '-s', self.settings['image'],
                         'mkpart', 'primary', 'fat16', str(partoffset), str(bootsize)])
            logging.debug("Starting root partition at %sMb", partoffset)
            self.runcmd(['parted', '-s', self.settings['image'],
                         'mkpart', 'primary', str(bootsize), extent])
        else:
            self.runcmd(['parted', '-s', self.settings['image'],
                         'mkpart', 'primary', '0%', extent])
        self.runcmd(['parted', '-s', self.settings['image'],
                     'set', '1', 'boot', 'on'])
        if self.settings['swap'] > 0:
            logging.debug("Creating swap partition")
            self.runcmd(['parted', '-s', self.settings['image'],
                         'mkpart', 'primary', 'linux-swap', extent, '100%'])

    def update_initramfs(self, rootdir):
        cmd = os.path.join('usr', 'sbin', 'update-initramfs')
        if os.path.exists(os.path.join(rootdir, cmd)):
            self.message("Updating the initramfs")
            self.runcmd(['chroot', rootdir, cmd, '-u'])

    def install_mbr(self):
        if os.path.exists("/sbin/install-mbr"):
            self.message('Installing MBR')
            self.runcmd(['install-mbr', self.settings['image']])
        else:
            msg = "mbr enabled but /sbin/install-mbr not found" \
                  " - please install the mbr package."
            raise cliapp.AppException(msg)

    def setup_kpartx(self):
        bootindex = None
        swapindex = None
        out = self.runcmd(['kpartx', '-avs', self.settings['image']])
        if self.settings['bootsize'] and self.settings['swap'] > 0:
            bootindex = 0
            rootindex = 1
            swapindex = 2
            parts = 3
        elif self.settings['bootsize']:
            bootindex = 0
            rootindex = 1
            parts = 2
        elif self.settings['swap'] > 0:
            rootindex = 0
            swapindex = 1
            parts = 2
        else:
            rootindex = 0
            parts = 1
        boot = None
        swap = None
        devices = [line.split()[2]
                   for line in out.splitlines()
                   if line.startswith('add map ')]
        if len(devices) != parts:
            msg = 'Surprising number of partitions - check output of losetup -a'
            logging.debug("%s" % self.runcmd(['losetup', '-a']))
            logging.debug("%s: devices=%s parts=%s", msg, devices, parts)
            raise cliapp.AppException(msg)
        root = '/dev/mapper/%s' % devices[rootindex]
        if self.settings['bootsize']:
            boot = '/dev/mapper/%s' % devices[bootindex]
        if self.settings['swap'] > 0:
            swap = '/dev/mapper/%s' % devices[swapindex]
        return root, boot, swap

    def mkfs(self, device, fstype):
        self.message('Creating filesystem %s' % fstype)
        self.runcmd(['mkfs', '-t', fstype, device])

    def debootstrap(self, rootdir):
        msg = "(%s)" % self.settings['variant'] if self.settings['variant'] else ''
        self.message('Debootstrapping %s %s' % (self.settings['distribution'], msg))

        include = self.settings['package']

        if not self.settings['foreign']:
            include.append('acpid')

        if self.settings['grub']:
            include.append('grub-pc')

        if not self.settings['no-kernel']:
            if self.settings['arch'] == 'i386':
                kernel_arch = '486'
            elif self.settings['arch'] == 'armhf':
                kernel_arch = 'armmp'
            else:
                kernel_arch = self.settings['arch']
            kernel_image = 'linux-image-%s' % kernel_arch
            include.append(kernel_image)

        if self.settings['sudo'] and 'sudo' not in include:
            include.append('sudo')

        args = ['debootstrap', '--arch=%s' % self.settings['arch']]

        if self.settings['package']:
            args.append(
                '--include=%s' % ','.join(include))
        if self.settings['foreign']:
            args.append('--foreign')
        if self.settings['variant']:
            args.append('--variant')
            args.append(self.settings['variant'])
        args += [self.settings['distribution'],
                 rootdir, self.settings['mirror']]
        logging.debug(" ".join(args))
        self.runcmd(args)
        if self.settings['foreign']:
            # set a noninteractive debconf environment for secondstage
            env = {
                "DEBIAN_FRONTEND": "noninteractive",
                "DEBCONF_NONINTERACTIVE_SEEN": "true",
                "LC_ALL": "C"
            }
            # add the mapping to the complete environment.
            env.update(os.environ)
            # First copy the binfmt handler over
            self.message('Setting up binfmt handler')
            shutil.copy(self.settings['foreign'], '%s/usr/bin/' % rootdir)
            # Next, run the package install scripts etc.
            self.message('Running debootstrap second stage')
            self.runcmd(['chroot', rootdir,
                         '/debootstrap/debootstrap', '--second-stage'],
                        env=env)

    def set_hostname(self, rootdir):
        hostname = self.settings['hostname']
        with open(os.path.join(rootdir, 'etc', 'hostname'), 'w') as f:
            f.write('%s\n' % hostname)

        etc_hosts = os.path.join(rootdir, 'etc', 'hosts')
        try:
            with open(etc_hosts, 'r') as f:
                data = f.read()
            with open(etc_hosts, 'w') as f:
                for line in data.splitlines():
                    if line.startswith('127.0.0.1'):
                        line += ' %s' % hostname
                    f.write('%s\n' % line)
        except IOError:
            pass

    def create_fstab(self, rootdir, rootdev, roottype, bootdev, boottype):  # pylint: disable=too-many-arguments
        def fsuuid(device):
            out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
                               '-s', 'UUID', device])
            return out.splitlines()[0].strip()

        if rootdev:
            rootdevstr = 'UUID=%s' % fsuuid(rootdev)
        else:
            rootdevstr = '/dev/sda1'

        if bootdev:
            bootdevstr = 'UUID=%s' % fsuuid(bootdev)
        else:
            bootdevstr = None

        fstab = os.path.join(rootdir, 'etc', 'fstab')
        with open(fstab, 'w') as f:
            f.write('proc /proc proc defaults 0 0\n')
            f.write('%s / %s errors=remount-ro 0 1\n' % (rootdevstr, roottype))
            if bootdevstr:
                f.write('%s /boot %s errors=remount-ro 0 2\n' % (bootdevstr, boottype))
                if self.settings['swap'] > 0:
                    f.write("/dev/sda3 swap swap defaults 0 0\n")
            elif self.settings['swap'] > 0:
                f.write("/dev/sda2 swap swap defaults 0 0\n")

    def install_debs(self, rootdir):
        if not self.settings['custom-package']:
            return
        self.message('Installing custom packages')
        tmp = os.path.join(rootdir, 'tmp', 'install_debs')
        os.mkdir(tmp)
        for deb in self.settings['custom-package']:
            shutil.copy(deb, tmp)
        filenames = [os.path.join('/tmp/install_debs', os.path.basename(deb))
                     for deb in self.settings['custom-package']]
        out, err, _ = \
            self.runcmd_unchecked(['chroot', rootdir, 'dpkg', '-i'] + filenames)
        logging.debug('stdout:\n%s', out)
        logging.debug('stderr:\n%s', err)
        out = self.runcmd(['chroot', rootdir,
                           'apt-get', '-f', '--no-remove', 'install'])
        logging.debug('stdout:\n%s', out)
        shutil.rmtree(tmp)

    def cleanup_apt_cache(self, rootdir):
        out = self.runcmd(['chroot', rootdir, 'apt-get', 'clean'])
        logging.debug('stdout:\n%s', out)

    def set_root_password(self, rootdir):
        if self.settings['root-password']:
            self.message('Setting root password')
            self.set_password(rootdir, 'root', self.settings['root-password'])
        elif self.settings['lock-root-password']:
            self.message('Locking root password')
            self.runcmd(['chroot', rootdir, 'passwd', '-l', 'root'])
        else:
            self.message('Give root an empty password')
            self.delete_password(rootdir, 'root')

    def create_users(self, rootdir):
        def create_user(user):
            self.runcmd(['chroot', rootdir, 'adduser', '--gecos', user,
                         '--disabled-password', user])
            if self.settings['sudo']:
                self.runcmd(['chroot', rootdir, 'adduser', user, 'sudo'])

        for userpass in self.settings['user']:
            if '/' in userpass:
                user, password = userpass.split('/', 1)
                create_user(user)
                self.set_password(rootdir, user, password)
            else:
                create_user(userpass)
                self.delete_password(rootdir, userpass)

    def set_password(self, rootdir, user, password):
        encrypted = crypt.crypt(password, '..')
        self.runcmd(['chroot', rootdir, 'usermod', '-p', encrypted, user])

    def delete_password(self, rootdir, user):
        self.runcmd(['chroot', rootdir, 'passwd', '-d', user])

    def remove_udev_persistent_rules(self, rootdir):
        self.message('Removing udev persistent cd and net rules')
        for x in ['70-persistent-cd.rules', '70-persistent-net.rules']:
            pathname = os.path.join(rootdir, 'etc', 'udev', 'rules.d', x)
            if os.path.exists(pathname):
                logging.debug('rm %s', pathname)
                os.remove(pathname)
            else:
                logging.debug('not removing non-existent %s', pathname)

    def setup_networking(self, rootdir):
        self.message('Setting up networking')

        f = open(os.path.join(rootdir, 'etc', 'network', 'interfaces'), 'w')
        f.write('auto lo\n')
        f.write('iface lo inet loopback\n')

        if self.settings['enable-dhcp']:
            f.write('\n')
            f.write('auto eth0\n')
            f.write('iface eth0 inet dhcp\n')

        f.close()

    def append_serial_console(self, rootdir):
        if self.settings['serial-console']:
            serial_command = self.settings['serial-console-command']
            logging.debug('adding getty to serial console')
            inittab = os.path.join(rootdir, 'etc/inittab')
            # to autologin, serial_command can contain '-a root'
            with open(inittab, 'a') as f:
                f.write('\nS0:23:respawn:%s\n' % serial_command)

    def _grub_serial_console(self, rootdir):
        cmdline = 'GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=tty1 console=ttyS0,38400n8"'
        terminal = 'GRUB_TERMINAL="serial gfxterm"'
        command = 'GRUB_SERIAL_COMMAND="serial --speed=38400 --unit=0 --parity=no --stop=1"'
        grub_cfg = os.path.join(rootdir, 'etc', 'default', 'grub')
        logging.debug("Allowing serial output in grub config %s", grub_cfg)
        with open(grub_cfg, 'a+') as cfg:
            cfg.write("# %s serial support\n" % os.path.basename(__file__))
            cfg.write("%s\n" % cmdline)
            cfg.write("%s\n" % terminal)
            cfg.write("%s\n" % command)

    def install_grub2(self, rootdev, rootdir):
        self.message("Configuring grub2")
        # rely on kpartx using consistent naming to map loop0p1 to loop0
        install_dev = os.path.join('/dev', os.path.basename(rootdev)[:-2])
        self.runcmd(['mount', '/dev', '-t', 'devfs', '-obind',
                     '%s' % os.path.join(rootdir, 'dev')])
        self.runcmd(['mount', '/proc', '-t', 'proc', '-obind',
                     '%s' % os.path.join(rootdir, 'proc')])
        self.runcmd(['mount', '/sys', '-t', 'sysfs', '-obind',
                     '%s' % os.path.join(rootdir, 'sys')])
        if self.settings['serial-console']:
            self._grub_serial_console(rootdir)

        try:
            self.runcmd(['chroot', rootdir, 'update-grub'])
            self.runcmd(['chroot', rootdir, 'grub-install', install_dev])
        except cliapp.AppException:
            self.message("Failed. Is grub2-common installed? Using extlinux.")
        self.runcmd(['umount', os.path.join(rootdir, 'sys')])
        self.runcmd(['umount', os.path.join(rootdir, 'proc')])
        self.runcmd(['umount', os.path.join(rootdir, 'dev')])
        self.install_extlinux(rootdev, rootdir)

    def install_extlinux(self, rootdev, rootdir):
        if not os.path.exists("/usr/bin/extlinux"):
            self.message("extlinux not installed, skipping.")
            return
        self.message('Installing extlinux')

        def find(pattern):
            dirname = os.path.join(rootdir, 'boot')
            basenames = os.listdir(dirname)
            logging.debug('find: %s', basenames)
            for basename in basenames:
                if re.search(pattern, basename):
                    return os.path.join('boot', basename)
            raise cliapp.AppException('Cannot find match: %s' % pattern)

        try:
            kernel_image = find('vmlinuz-.*')
            initrd_image = find('initrd.img-.*')
        except cliapp.AppException as e:
            self.message("Unable to find kernel. Not installing extlinux.")
            logging.debug("No kernel found. %s. Skipping install of extlinux.", e)
            return

        out = self.runcmd(['blkid', '-c', '/dev/null', '-o', 'value',
                           '-s', 'UUID', rootdev])
        uuid = out.splitlines()[0].strip()

        conf = os.path.join(rootdir, 'extlinux.conf')
        logging.debug('configure extlinux %s', conf)
        kserial = 'console=ttyS0,115200' if self.settings['serial-console'] else ''
        extserial = 'serial 0 115200' if self.settings['serial-console'] else ''
        msg = '''
default linux
timeout 1

label linux
kernel %(kernel)s
append initrd=%(initrd)s root=UUID=%(uuid)s ro %(kserial)s
%(extserial)s
''' % {
            'kernel': kernel_image,  # pylint: disable=bad-continuation
            'initrd': initrd_image,  # pylint: disable=bad-continuation
            'uuid': uuid,  # pylint: disable=bad-continuation
            'kserial': kserial,  # pylint: disable=bad-continuation
            'extserial': extserial,  # pylint: disable=bad-continuation
        }  # pylint: disable=bad-continuation
        logging.debug("extlinux config:\n%s", msg)

        # python multiline string substitution is just ugly.
        # use an external file or live with the mangling, no point in
        # mangling the string to remove spaces just to keep it pretty in source.
        f = open(conf, 'w')
        f.write(msg)

        self.runcmd(['extlinux', '--install', rootdir])
        self.runcmd(['sync'])
        time.sleep(2)

    def optimize_image(self, rootdir):
        """
        Filing up the image with zeros will increase its compression rate
        """
        if not self.settings['sparse']:
            zeros = os.path.join(rootdir, 'ZEROS')
            self.runcmd_unchecked(['dd', 'if=/dev/zero', 'of=' + zeros, 'bs=1M'])
            self.runcmd(['rm', '-f', zeros])

    def squash(self):
        """
        Run squashfs on the image.
        """
        if not os.path.exists('/usr/bin/mksquashfs'):
            logging.warning("Squash selected but mksquashfs not found!")
            return
        self.message("Running mksquashfs")
        suffixed = "%s.squashfs" % self.settings['image']
        self.runcmd(['mksquashfs', self.settings['image'],
                     suffixed,
                     '-no-progress', '-comp', 'xz'], ignore_fail=False)
        os.unlink(self.settings['image'])
        self.settings['image'] = suffixed

    def cleanup_system(self):
        # Clean up after any errors.

        self.message('Cleaning up')

        # Umount in the reverse mount order
        if self.settings['image']:
            for i in range(len(self.mount_points) - 1, -1, -1):
                mount_point = self.mount_points[i]
                try:
                    self.runcmd(['umount', mount_point], ignore_fail=False)
                except cliapp.AppException:
                    logging.debug("umount failed, sleeping and trying again")
                    time.sleep(5)
                    self.runcmd(['umount', mount_point], ignore_fail=False)

            self.runcmd(['kpartx', '-d', self.settings['image']], ignore_fail=True)

        for dirname in self.remove_dirs:
            shutil.rmtree(dirname)

    def customize(self, rootdir):
        script = self.settings['customize']
        if not script:
            return
        if not os.path.exists(script):
            example = os.path.join("/usr/share/vmdebootstrap/examples/", script)
            if not os.path.exists(example):
                self.message("Unable to find %s" % script)
                return
            script = example
        self.message('Running customize script %s' % script)
        logging.info("rootdir=%s image=%s", rootdir, self.settings['image'])
        with open('/dev/tty', 'w') as tty:
            try:
                cliapp.runcmd([script, rootdir, self.settings['image']], stdout=tty, stderr=tty)
            except IOError as e:
                subprocess.call([script, rootdir, self.settings['image']])

    def create_tarball(self, rootdir):
        # Create a tarball of the disk's contents
        # shell out to runcmd since it more easily handles rootdir
        self.message('Creating tarball of disk contents')
        self.runcmd(['tar', '-cf', self.settings['tarball'], '-C', rootdir, '.'])

    def chown(self):
        # Change image owner after completed build
        if self.settings['image']:
            filename = self.settings['image']
        elif self.settings['tarball']:
            filename = self.settings['tarball']
        else:
            return
        self.message("Changing owner to %s" % self.settings["owner"])
        subprocess.call(["chown", self.settings["owner"], filename])

    def list_installed_pkgs(self, rootdir):
        # output the list of installed packages for sources identification
        self.message("Creating a list of installed binary package names")
        out = self.runcmd(['chroot', rootdir,
                           'dpkg-query', '-W', "-f='${Package}.deb\n'"])
        with open('dpkg.list', 'w') as dpkg:
            dpkg.write(out)

    def configure_apt(self, rootdir):
        # use the distribution and mirror to create an apt source
        self.message("Configuring apt to use distribution and mirror")
        conf = os.path.join(rootdir, 'etc', 'apt', 'sources.list.d', 'base.list')
        logging.debug('configure apt %s', conf)
        mirror = self.settings['mirror']
        if self.settings['apt-mirror']:
            mirror = self.settings['apt-mirror']
            self.message("Setting apt mirror to %s" % mirror)
        os.unlink(os.path.join(rootdir, 'etc', 'apt', 'sources.list'))
        f = open(conf, 'w')
        line = 'deb %s %s main\n' % (mirror, self.settings['distribution'])
        f.write(line)
        line = '#deb-src %s %s main\n' % (mirror, self.settings['distribution'])
        f.write(line)
        f.close()
        # ensure the apt sources have valid lists
        self.runcmd(['chroot', rootdir, 'apt-get', '-qq', 'update'])

if __name__ == '__main__':
    VmDebootstrap(version=__version__).run()