Example #1
0
def main():
    common.check_filesystem()

    # Basic sanity checks of files and paths that absolutely need to exist.
    message.sub_info("Doing sanity checks")
    lsb_file = misc.join_paths(config.FILESYSTEM_DIR, "etc/lsb-release")
    if not os.path.isfile(lsb_file):
        raise (message.exception(lsb_file + " does not exist"))

    isolinux_dir = misc.join_paths(config.ISO_DIR, "isolinux")
    if not os.path.isdir(isolinux_dir):
        raise (message.exception(isolinux_dir + " does not exist"))

    if misc.search_file("999:999", misc.join_paths(config.FILESYSTEM_DIR, "etc/passwd")):
        raise (message.exception("User with UID 999 exists, this mean that automatic login will fail"))
    elif misc.search_file("999:999", misc.join_paths(config.FILESYSTEM_DIR, "etc/group")):
        raise (message.exception("Group with GID 999 exists, this mean that automatic login will fail"))

    casper_dir = misc.join_paths(config.ISO_DIR, "casper")
    if not os.path.isdir(casper_dir):
        message.sub_debug("Creating", casper_dir)
        os.makedirs(casper_dir)

    base_file = misc.join_paths(config.ISO_DIR, ".disk/base_installable")
    if os.path.isfile(misc.join_paths(config.FILESYSTEM_DIR, "usr/bin/ubiquity")):
        if not os.path.isfile(base_file):
            message.sub_debug("Creating", base_file)
            misc.write_file(base_file, "")
    elif os.path.isfile(base_file):
        message.sub_debug("Removing", base_file)
        os.unlink(base_file)

    # Acquire distribution information from the FileSystem
    message.sub_info("Gathering information")
    arch = misc.chroot_exec(("dpkg", "--print-architecture"), prepare=False, mount=False, output=True)
    distrib = common.get_value(config.FILESYSTEM_DIR + "/etc/lsb-release", "DISTRIB_ID=")
    release = common.get_value(config.FILESYSTEM_DIR + "/etc/lsb-release", "DISTRIB_RELEASE=")

    # It's really annoying to override the output filename other ways.
    # If you actually try to change lsb-release, you end up breaking apt.
    livecd_file = misc.join_paths(config.FILESYSTEM_DIR, "etc/livecd-release")
    if os.path.isfile(livecd_file):
        distrib = common.get_value(config.FILESYSTEM_DIR + "/etc/livecd-release", "DISTRIB_ID=")
        release = common.get_value(config.FILESYSTEM_DIR + "/etc/livecd-release", "DISTRIB_RELEASE=")
        message.sub_debug("Distribution and Release overriden by /etc/livecd-release")
        # Just overwrite the variables if the file actually exists, it's cleaner.

    message.sub_debug("Architecture", arch)
    message.sub_debug("Distribution (DISTRIB_ID)", distrib)
    message.sub_debug("Release (DISTRIB_RELEASE)", release)

    # Remove files, by name, that we know we must repopulate if they exist.
    message.sub_info("Cleaning up")
    cleanup_files = [
        "casper/filesystem.squashfs",
        "casper/initrd.lz",
        "casper/vmlinuz",
        "casper/vmlinuz.efi",
        "casper/filesystem.manifest",
        "casper/filesystem.size",
    ]
    cleanup_files.extend(glob.glob(".disk/casper-uuid-*"))
    for sfile in cleanup_files:
        full_file = misc.join_paths(config.ISO_DIR, sfile)
        if os.path.exists(full_file):
            message.sub_debug("Removing", full_file)
            os.unlink(full_file)

    # Define the checksum files, and the ISO filename.
    md5sum_iso_file = misc.join_paths(config.WORK_DIR, "md5sum")
    sha1sum_iso_file = misc.join_paths(config.WORK_DIR, "sha1sum")
    sha256sum_iso_file = misc.join_paths(config.WORK_DIR, "sha256sum")
    iso_file = "%s/%s-%s-%s.iso" % (config.WORK_DIR, distrib, arch, release)
    if os.path.exists(iso_file):
        message.sub_debug("Removing", iso_file)
        os.unlink(iso_file)
    if os.path.exists(md5sum_iso_file):
        message.sub_debug("Removing", md5sum_iso_file)
        os.unlink(md5sum_iso_file)
    if os.path.exists(sha1sum_iso_file):
        message.sub_debug("Removing", sha1sum_iso_file)
        os.unlink(sha1sum_iso_file)
    if os.path.exists(sha256sum_iso_file):
        message.sub_debug("Removing", sha256sum_iso_file)
        os.unlink(sha256sum_iso_file)

    # Detect files needed for booting, the kernel, initramfs, xen and anything else.
    detect_boot()
    if not vmlinuz:
        message.sub_info("Re-installing kernel")
        misc.chroot_exec(("apt-get", "purge", "--yes", "linux-image*", "-q"))
        misc.chroot_exec(("apt-get", "install", "--yes", "linux-signed-generic", "-q"))
        misc.chroot_exec(("apt-get", "clean"))
    else:
        message.sub_info("Updating initramfs")
        misc.chroot_exec(("update-initramfs", "-k", "all", "-t", "-u"))
    detect_boot()

    if not initrd or not vmlinuz:
        raise (message.exception("Missing boot file (initrd or vmlinuz)"))
    else:
        message.sub_info("Copying boot files")
        message.sub_debug("Initrd", initrd)
        message.sub_debug("Vmlinuz", vmlinuz)
        misc.copy_file(initrd, misc.join_paths(config.ISO_DIR, "casper/initrd.lz"))

        # FIXME: extend to support grub
        efi_boot_entry = False
        isolinux_dir = config.ISO_DIR + "/isolinux"
        if os.path.isdir(isolinux_dir):
            for sfile in os.listdir(isolinux_dir):
                if sfile.endswith(".cfg") and misc.search_file("vmlinuz.efi", isolinux_dir + "/" + sfile):
                    message.sub_debug("Found EFI entry in isolinux conf", sfile)
                    efi_boot_entry = True
        if os.path.isdir(misc.join_paths(config.ISO_DIR, "efi/boot")) or efi_boot_entry:
            message.sub_debug("Copying EFI vmlinuz")
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, "casper/vmlinuz.efi"))
            os.link(
                misc.join_paths(config.ISO_DIR, "casper/vmlinuz.efi"), misc.join_paths(config.ISO_DIR, "casper/vmlinuz")
            )
            # EFI Kernels are still loadable by grub, modern ISOs lack a bare vmlinuz.
            # mkisofs/genisoimage -cache-inodes reuses hard linked inodes.
        else:
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, "casper/vmlinuz"))
            # We only need to copy the bare kernel if we're not using EFI at all.

    # Copy optional boot-enablement packages onto the ISO, if found.
    if mt86plus:
        message.sub_debug("Memtest86+ kernel", mt86plus)
        misc.copy_file(mt86plus, misc.join_paths(config.ISO_DIR, "install/mt86plus"))
    if xen_kernel:
        message.sub_debug("Xen kernel", xen_kernel)
        misc.copy_file(xen_kernel, misc.join_paths(config.ISO_DIR, "casper/" + os.path.basename(xen_kernel)))
    if xen_efi:
        message.sub_debug("Xen EFI kernel", xen_efi)
        misc.copy_file(xen_efi, misc.join_paths(config.ISO_DIR, "casper/" + os.path.basename(xen_efi)))
    if ipxe_kernel:
        message.sub_debug("iPXE kernel", ipxe_kernel)
        misc.copy_file(ipxe_kernel, misc.join_paths(config.ISO_DIR, "casper/" + os.path.basename(ipxe_kernel)))
    if ipxe_efi:
        message.sub_debug("iPXE EFI kernel", ipxe_efi)
        misc.copy_file(ipxe_efi, misc.join_paths(config.ISO_DIR, "casper/" + os.path.basename(ipxe_efi)))

    message.sub_info("Extracting casper UUID")
    confdir = config.FILESYSTEM_DIR + "/conf"
    if os.path.isdir(confdir):
        shutil.rmtree(confdir)
    os.makedirs(confdir)
    try:
        misc.chroot_exec(
            "zcat " + initrd.replace(config.FILESYSTEM_DIR, "") + " | cpio --quiet -id conf/uuid.conf",
            shell=True,
            cwd=config.FILESYSTEM_DIR,
        )
        kernel = re.search("initrd.img-*.*.*-*-(.*)", initrd).group(1)
        message.sub_debug("Kernel", kernel)
        misc.copy_file(confdir + "/uuid.conf", misc.join_paths(config.ISO_DIR, ".disk/casper-uuid-" + kernel))
    finally:
        shutil.rmtree(confdir)

    # Define some default compression parameters, including a 1MB blocksize for all compressors.
    compression_parameters = ("-b", "1048576", "-comp", config.COMPRESSION)
    if config.COMPRESSION == "xz":  # Append additional compression parameters for xz.
        # Using the branch-call-jump filter provides a compression boost with executable code.
        # This can save a hundred megabytes easily, on an 800MB ISO. The dictionary size must
        # match the block size, and it's advisable to use larger block sizes, like 1MB or 4MB.
        compression_parameters += ("-Xbcj", "x86", "-Xdict-size", "100%")
    message.sub_info("SquashFS Compression parameters", compression_parameters)

    # Create the compressed filesystem
    message.sub_info("Creating SquashFS Compressed Filesystem")
    make_squash_fs = (
        "mksquashfs",
        config.FILESYSTEM_DIR,
        misc.join_paths(config.ISO_DIR, "casper/filesystem.squashfs"),
        "-wildcards",
        "-no-recovery",
        "-noappend",
        "-ef",
        os.path.join(sys.prefix, "share/customizer/exclude.list"),
    )
    misc.system_command(make_squash_fs + compression_parameters)

    message.sub_info("Checking SquashFS filesystem size")
    sfs_size = os.path.getsize(misc.join_paths(config.ISO_DIR, "casper/filesystem.squashfs"))
    message.sub_debug("SquashFS filesystem size", sfs_size)
    if sfs_size > 4000000000:
        raise (message.exception("The SquashFS filesystem size is greater than 4GB"))

    message.sub_info("Creating filesystem.size")
    fs_size = 0
    for root, subdirs, files in os.walk(config.FILESYSTEM_DIR):
        for sfile in files:
            sfull = os.path.join(root, sfile)
            if os.path.islink(sfull):
                continue
            # FIXME: respect ignored files from exclude.list
            fs_size += os.path.getsize(sfull)
    message.sub_debug("Root filesystem size", fs_size)
    misc.write_file(misc.join_paths(config.ISO_DIR, "casper/filesystem.size"), str(fs_size))

    message.sub_info("Creating filesystem.manifest")
    lpackages = misc.chroot_exec(
        ("dpkg-query", "-W", "--showformat=${Package} ${Version}\\n"), prepare=False, mount=False, output=True
    )
    message.sub_debug("Packages", lpackages)
    misc.write_file(misc.join_paths(config.ISO_DIR, "casper/filesystem.manifest"), lpackages)

    # FIXME: do some kung-fu to check if packages are installed
    # and remove them from filesystem.manifest-remove if they are not

    # Creating a md5sum.txt file fixes lubuntu's integrity check.
    md5sums_file = misc.join_paths(config.ISO_DIR, "md5sum.txt")
    if os.path.isfile(md5sums_file):
        message.sub_info("Creating md5sum.txt")
        misc.write_file(md5sums_file, "")
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith("md5sum.txt"):
                continue
            if sfile.endswith("SHA256SUMS"):
                continue
            message.sub_debug("MD5 Checksumming", sfile)
            checksum = misc.generate_hash_for_file("md5", sfile)
            misc.append_file(md5sums_file, checksum + "  ." + sfile.replace(config.ISO_DIR, "") + "\n")

    # Creating a SHA256SUMS file fixes ubuntu-mini-remix's integrity check.
    shasums_file = misc.join_paths(config.ISO_DIR, "SHA256SUMS")
    if os.path.isfile(shasums_file):
        message.sub_info("Creating SHA256SUMS")
        misc.write_file(shasums_file, "")
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith("md5sum.txt"):
                continue
            if sfile.endswith("SHA256SUMS"):
                continue
            message.sub_debug("SHA256 Checksumming", sfile)
            checksum = misc.generate_hash_for_file("sha256", sfile)
            misc.append_file(shasums_file, checksum + "  ." + sfile.replace(config.ISO_DIR, "") + "\n")

    # Create the ISO filesystem
    message.sub_info("Creating ISO")
    os.chdir(config.ISO_DIR)
    misc.system_command(
        (
            "xorriso",
            "-as",
            "mkisofs",
            "-r",
            "-V",
            distrib + "-" + arch + "-" + release,
            "-b",
            "isolinux/isolinux.bin",
            "-c",
            "isolinux/boot.cat",
            "-J",
            "-l",
            "-no-emul-boot",
            "-boot-load-size",
            "4",
            "-boot-info-table",
            "-o",
            iso_file,
            "-cache-inodes",
            "-input-charset",
            "utf-8",
            ".",
        )
    )

    message.sub_info("Creating ISO checksums")
    md5checksum = misc.generate_hash_for_file("md5", iso_file)
    message.sub_info("ISO md5 checksum", md5checksum)
    misc.append_file(md5sum_iso_file, md5checksum + "  ." + iso_file.replace(config.WORK_DIR, "") + "\n")
    sha1checksum = misc.generate_hash_for_file("sha1", iso_file)
    message.sub_info("ISO sha1 checksum", sha1checksum)
    misc.append_file(sha1sum_iso_file, sha1checksum + "  ." + iso_file.replace(config.WORK_DIR, "") + "\n")
    sha256checksum = misc.generate_hash_for_file("sha256", iso_file)
    message.sub_info("ISO sha256 checksum", sha256checksum)
    misc.append_file(sha256sum_iso_file, sha256checksum + "  ." + iso_file.replace(config.WORK_DIR, "") + "\n")

    message.sub_info("Successfuly created ISO image", iso_file)
Example #2
0
def main():
    common.check_filesystem()

    message.sub_info('Doing sanity checks')
    lsb_file = misc.join_paths(config.FILESYSTEM_DIR, 'etc/lsb-release')
    if not os.path.isfile(lsb_file):
        raise(message.exception(lsb_file + ' does not exists'))

    isolinux_dir = misc.join_paths(config.ISO_DIR, 'isolinux')
    if not os.path.isdir(isolinux_dir):
        raise(message.exception(isolinux_dir + ' does not exist'))

    if misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/passwd')):
        raise(message.exception('User with UID 999 exists, this mean that automatic login will fail'))
    elif misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/group')):
        raise(message.exception('Group with GID 999 exists, this mean that automatic login will fail'))

    casper_dir = misc.join_paths(config.ISO_DIR, 'casper')
    if not os.path.isdir(casper_dir):
        message.sub_debug('Creating', casper_dir)
        os.makedirs(casper_dir)

    base_file = misc.join_paths(config.ISO_DIR, '.disk/base_installable')
    if os.path.isfile(misc.join_paths(config.FILESYSTEM_DIR, 'usr/bin/ubiquity')):
        if not os.path.isfile(base_file):
            message.sub_debug('Creating', base_file)
            misc.write_file(base_file, '')
    elif os.path.isfile(base_file):
        message.sub_debug('Removing', base_file)
        os.unlink(base_file)

    message.sub_info('Gathering information')
    arch = misc.chroot_exec(('dpkg', '--print-architecture'), prepare=False, \
        mount=False, output=True)
    distrib = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_ID=')
    release = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_RELEASE=')
    message.sub_debug('Architecture', arch)
    message.sub_debug('Distribution (DISTRIB_ID)', distrib)
    message.sub_debug('Release (DISTRIB_RELEASE)', release)

    message.sub_info('Cleaning up')
    cleanup_files = ['casper/filesystem.squashfs', 'casper/initrd.lz', \
        'casper/vmlinuz', 'casper/vmlinuz.efi', 'casper/filesystem.manifest', \
        'casper/filesystem.size']
    cleanup_files.extend(glob.glob('.disk/casper-uuid-*'))
    for sfile in cleanup_files:
        full_file = misc.join_paths(config.ISO_DIR, sfile)
        if os.path.exists(full_file):
            message.sub_debug('Removing', full_file)
            os.unlink(full_file)

    iso_file = '%s/%s-%s-%s.iso' % (config.WORK_DIR, distrib, arch, release)
    if os.path.exists(iso_file):
        message.sub_debug('Removing', iso_file)
        os.unlink(iso_file)

    detect_boot()
    if not vmlinuz:
        message.sub_info('Re-installing kernel')
        misc.chroot_exec(('apt-get', 'purge', '--yes', 'linux-image*', '-q'))
        misc.chroot_exec(('apt-get', 'install', '--yes', \
            'linux-image-generic', '-q'))
        misc.chroot_exec(('apt-get', 'clean'))
    else:
        message.sub_info('Updating initramfs')
        misc.chroot_exec(('update-initramfs', '-k', 'all', '-t', '-u'))
    detect_boot()

    if not initrd or not vmlinuz:
        raise(message.exception('Missing boot file (initrd or vmlinuz)'))
    else:
        message.sub_info('Copying boot files')
        message.sub_debug('Initrd', initrd)
        message.sub_debug('Vmlinuz', vmlinuz)
        misc.copy_file(initrd, misc.join_paths(config.ISO_DIR, 'casper/initrd.lz'))
        misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, 'casper/vmlinuz'))
        # FIXME: extend to support grub
        efi_boot_entry = False
        isolinux_dir = config.ISO_DIR + '/isolinux'
        if os.path.isdir(isolinux_dir):
            for sfile in os.listdir(isolinux_dir):
                if sfile.endswith('.cfg') and misc.search_file('vmlinuz.efi', isolinux_dir + '/' + sfile):
                    message.sub_debug('Found EFI entry in isolinux conf', sfile)
                    efi_boot_entry = True
        if os.path.isdir(misc.join_paths(config.ISO_DIR, 'efi/boot')) or \
            efi_boot_entry:
            message.sub_debug('Copying EFI vmlinuz')
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz.efi'))

    message.sub_info('Extracting casper UUID')
    confdir = config.FILESYSTEM_DIR + '/conf'
    if os.path.isdir(confdir):
        shutil.rmtree(confdir)
    os.makedirs(confdir)
    try:
        misc.chroot_exec('zcat ' + initrd.lstrip(config.FILESYSTEM_DIR) + ' | ' + ' cpio --quiet -id conf/uuid.conf', shell=True)
        kernel = re.search('initrd.img-*.*.*-*-(.*)', initrd).group(1)
        message.sub_debug('Kernel', kernel)
        misc.copy_file(confdir + '/uuid.conf', misc.join_paths(config.ISO_DIR, \
            '.disk/casper-uuid-' + kernel))
    finally:
        shutil.rmtree(confdir)

    message.sub_info('Creating squashed FileSystem')
    misc.system_command(('mksquashfs', config.FILESYSTEM_DIR, \
        misc.join_paths(config.ISO_DIR, 'casper/filesystem.squashfs'), \
        '-wildcards', '-ef', os.path.join(sys.prefix, 'share/customizer/exclude.list'), \
        '-comp', config.COMPRESSION))

    message.sub_info('Checking SquashFS filesystem size')
    sfs_size = os.path.getsize(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.squashfs'))
    message.sub_debug('SquashFS filesystem size', sfs_size)
    if sfs_size > 4000000000:
        raise(message.exception('The SquashFS filesystem size is greater than 4GB'))

    message.sub_info('Creating filesystem.size')
    fs_size = 0
    for root, subdirs, files in os.walk(config.FILESYSTEM_DIR):
        for sfile in files:
            sfull = os.path.join(root, sfile)
            if os.path.islink(sfull):
                continue
            # FIXME: respect ignored files from exclude.list
            fs_size += os.path.getsize(sfull)
    message.sub_debug('Root filesystem size', fs_size)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.size'), str(fs_size))

    message.sub_info('Creating filesystem.manifest')
    lpackages = misc.chroot_exec(('dpkg-query', '-W', \
        '--showformat=${Package} ${Version}\\n'), prepare=False, mount=False, \
        output=True)
    message.sub_debug('Packages', lpackages)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.manifest'), lpackages)

    # FIXME: do some kung-fu to check if packages are installed
    # and remove them from filesystem.manifest-remove if they are not

    md5sums_file = misc.join_paths(config.ISO_DIR, 'md5sum.txt')
    if os.path.isfile(md5sums_file):
        message.sub_info('Creating md5sum.txt')
        misc.write_file(md5sums_file, '')
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith('md5sum.txt'):
                continue

            # FIXME: read in chunks
            message.sub_debug('Checksuming', sfile)
            checksum = hashlib.md5(misc.read_file(sfile)).hexdigest()
            misc.append_file(md5sums_file, checksum + '  .' + \
                sfile.replace(config.ISO_DIR, '') +'\n')

    message.sub_info('Creating ISO')
    os.chdir(config.ISO_DIR)
    misc.system_command(('xorriso', '-as', 'mkisofs', '-r', '-V', \
        distrib + '-' + arch + '-' + release, '-b', 'isolinux/isolinux.bin', \
        '-c', 'isolinux/boot.cat', '-J', '-l', '-no-emul-boot', \
        '-boot-load-size', '4', '-boot-info-table', '-o', iso_file, \
        '-input-charset', 'utf-8', '.'))

    message.sub_info('Successfuly created ISO image', iso_file)
Example #3
0
def main():
    common.check_filesystem()

    # Basic sanity checks of files and paths that absolutely need to exist.
    message.sub_info('Doing sanity checks')
    lsb_file = misc.join_paths(config.FILESYSTEM_DIR, 'etc/lsb-release')
    if not os.path.isfile(lsb_file):
        raise(message.exception(lsb_file + ' does not exist'))

    isolinux_dir = misc.join_paths(config.ISO_DIR, 'isolinux')
    if not os.path.isdir(isolinux_dir):
        raise(message.exception(isolinux_dir + ' does not exist'))

    if misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/passwd')):
        raise(message.exception('User with UID 999 exists, this means automatic login will fail'))
    elif misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/group')):
        raise(message.exception('Group with GID 999 exists, this means automatic login will fail'))

    casper_dir = misc.join_paths(config.ISO_DIR, 'casper')
    if not os.path.isdir(casper_dir):
        message.sub_debug('Creating', casper_dir)
        os.makedirs(casper_dir)

    base_file = misc.join_paths(config.ISO_DIR, '.disk/base_installable')
    if os.path.isfile(misc.join_paths(config.FILESYSTEM_DIR, 'usr/bin/ubiquity')):
        if not os.path.isfile(base_file):
            message.sub_debug('Creating', base_file)
            misc.write_file(base_file, '')
    elif os.path.isfile(base_file):
        message.sub_debug('Removing', base_file)
        os.unlink(base_file)

    # Acquire distribution information from the FileSystem
    message.sub_info('Gathering information')
    arch = misc.chroot_exec(('dpkg', '--print-architecture'), prepare=False, \
        mount=False, output=True)
    distrib = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_ID=')
    release = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_RELEASE=')
    message.sub_debug('Architecture', arch)
    message.sub_debug('Distribution (DISTRIB_ID)', distrib)
    message.sub_debug('Release (DISTRIB_RELEASE)', release)

    # Remove files, by name, that we know we must repopulate if they exist.
    message.sub_info('Cleaning up')
    cleanup_files = ['casper/filesystem.squashfs', 'casper/initrd.lz', \
        'casper/vmlinuz', 'casper/vmlinuz.efi', 'casper/filesystem.manifest', \
        'casper/filesystem.size']
    cleanup_files.extend(glob.glob('.disk/casper-uuid-*'))
    for sfile in cleanup_files:
        full_file = misc.join_paths(config.ISO_DIR, sfile)
        if os.path.exists(full_file):
            message.sub_debug('Removing', full_file)
            os.unlink(full_file)

    # Define the checksum files, and the ISO filename.
    md5sum_iso_file = misc.join_paths(config.WORK_DIR, 'md5sum')
    sha1sum_iso_file = misc.join_paths(config.WORK_DIR, 'sha1sum')
    sha256sum_iso_file = misc.join_paths(config.WORK_DIR, 'sha256sum')
    iso_file = '%s/%s-%s-%s.iso' % (config.WORK_DIR, distrib, arch, release)
    if os.path.exists(iso_file):
        message.sub_debug('Removing', iso_file)
        os.unlink(iso_file)
    if os.path.exists(md5sum_iso_file):
        message.sub_debug('Removing', md5sum_iso_file)
        os.unlink(md5sum_iso_file)
    if os.path.exists(sha1sum_iso_file):
        message.sub_debug('Removing', sha1sum_iso_file)
        os.unlink(sha1sum_iso_file)
    if os.path.exists(sha256sum_iso_file):
        message.sub_debug('Removing', sha256sum_iso_file)
        os.unlink(sha256sum_iso_file)

    # Detect files needed for booting, the kernel, initramfs, xen and anything else.
    detect_boot()
    if not vmlinuz:
        message.sub_info('Re-installing kernel')
        misc.chroot_exec(('apt-get', 'purge', '--yes', 'linux-image*', '-q'))
        misc.chroot_exec(('apt-get', 'install', '--yes', \
            'linux-image-generic', '-q'))
        misc.chroot_exec(('apt-get', 'clean'))
    else:
        message.sub_info('Updating initramfs')
        misc.chroot_exec(('update-initramfs', '-k', 'all', '-t', '-u'))
    detect_boot()

    if not initrd or not vmlinuz:
        raise(message.exception('Missing boot file (initrd or vmlinuz)'))
    else:
        message.sub_info('Copying boot files')
        message.sub_debug('Initrd', initrd)
        message.sub_debug('Vmlinuz', vmlinuz)
        misc.copy_file(initrd, misc.join_paths(config.ISO_DIR, 'casper/initrd.lz'))
        
        # FIXME: extend to support grub
        efi_boot_entry = False
        isolinux_dir = config.ISO_DIR + '/isolinux'
        if os.path.isdir(isolinux_dir):
            for sfile in os.listdir(isolinux_dir):
                if sfile.endswith('.cfg') and misc.search_file('vmlinuz.efi', isolinux_dir + '/' + sfile):
                    message.sub_debug('Found EFI entry in isolinux conf', sfile)
                    efi_boot_entry = True
        if os.path.isdir(misc.join_paths(config.ISO_DIR, 'efi/boot')) or \
            efi_boot_entry:
            message.sub_debug('Copying EFI vmlinuz')
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz.efi'))
            os.link(misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz.efi'), misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz'))
            # EFI Kernels are still loadable by grub, modern ISOs lack a bare vmlinuz.
            # mkisofs/genisoimage -cache-inodes reuses hard linked inodes.
        else:
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, 'casper/vmlinuz'))
            # We only need to copy the bare kernel if we're not using EFI at all.

    # Copy optional boot-enablement packages onto the ISO, if found.
    if mt86plus:
        message.sub_debug('Memtest86+ kernel', mt86plus)
        misc.copy_file(mt86plus, misc.join_paths(config.ISO_DIR, 'install/mt86plus'))
    if xen_kernel:
        message.sub_debug('Xen kernel', xen_kernel)
        misc.copy_file(xen_kernel, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(xen_kernel)))
    if xen_efi:
        message.sub_debug('Xen EFI kernel', xen_efi)
        misc.copy_file(xen_efi, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(xen_efi)))
    if ipxe_kernel:
        message.sub_debug('iPXE kernel', ipxe_kernel)
        misc.copy_file(ipxe_kernel, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(ipxe_kernel)))
    if ipxe_efi:
        message.sub_debug('iPXE EFI kernel', ipxe_efi)
        misc.copy_file(ipxe_efi, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(ipxe_efi)))

    message.sub_info('Extracting casper UUID')
    confdir = config.FILESYSTEM_DIR + '/conf'
    if os.path.isdir(confdir):
        shutil.rmtree(confdir)
    os.makedirs(confdir)
    try:
        misc.chroot_exec('zcat ' + initrd.replace(config.FILESYSTEM_DIR, '') + ' | cpio --quiet -id conf/uuid.conf', \
            shell=True, cwd=config.FILESYSTEM_DIR)
        kernel = re.search('initrd.img-*.*.*-*-(.*)', initrd).group(1)
        message.sub_debug('Kernel', kernel)
        misc.copy_file(confdir + '/uuid.conf', misc.join_paths(config.ISO_DIR, \
            '.disk/casper-uuid-' + kernel))
    finally:
        shutil.rmtree(confdir)

    # Define some default compression parameters, including a 1MB blocksize for all compressors.
    compression_parameters = ('-b', '1048576', '-comp', config.COMPRESSION)
    if config.COMPRESSION == 'xz':  # Append additional compression parameters for xz.
        # Using the branch-call-jump filter provides a compression boost with executable code.
        # This can save a hundred megabytes easily, on an 800MB ISO. The dictionary size must
        # match the block size, and it's advisable to use larger block sizes, like 1MB or 4MB.
        compression_parameters += ('-Xbcj', 'x86', '-Xdict-size', '100%')
    message.sub_info('SquashFS Compression parameters', compression_parameters)

    # Create the compressed filesystem
    message.sub_info('Creating SquashFS compressed filesystem')
    make_squash_fs = ('mksquashfs', config.FILESYSTEM_DIR, \
        misc.join_paths(config.ISO_DIR, 'casper/filesystem.squashfs'), \
        '-wildcards', '-no-recovery', '-noappend', \
        '-ef', os.path.join(sys.prefix, 'share/customizer/exclude.list'))
    misc.system_command(make_squash_fs + compression_parameters)

    message.sub_info('Checking SquashFS filesystem size')
    sfs_size = os.path.getsize(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.squashfs'))
    message.sub_debug('SquashFS filesystem size', sfs_size)
    if sfs_size > 4000000000:
        raise(message.exception('The SquashFS filesystem size is greater than 4GB'))

    message.sub_info('Creating filesystem.size')
    fs_size = 0
    for root, subdirs, files in os.walk(config.FILESYSTEM_DIR):
        for sfile in files:
            sfull = os.path.join(root, sfile)
            if os.path.islink(sfull):
                continue
            # FIXME: respect ignored files from exclude.list
            fs_size += os.path.getsize(sfull)
    message.sub_debug('Root filesystem size', fs_size)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.size'), str(fs_size))

    message.sub_info('Creating filesystem.manifest')
    lpackages = misc.chroot_exec(('dpkg-query', '-W', \
        '--showformat=${Package} ${Version}\\n'), prepare=False, mount=False, \
        output=True)
    message.sub_debug('Packages', lpackages)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.manifest'), lpackages)

    # FIXME: do some kung-fu to check if packages are installed
    # and remove them from filesystem.manifest-remove if they are not

    # Creating a md5sum.txt file fixes lubuntu's integrity check.
    md5sums_file = misc.join_paths(config.ISO_DIR, 'md5sum.txt')
    if os.path.isfile(md5sums_file):
        message.sub_info('Creating md5sum.txt')
        misc.write_file(md5sums_file, '')
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith('md5sum.txt'):
                continue
            if sfile.endswith('SHA256SUMS'):
                continue
            message.sub_debug('MD5 Checksumming', sfile)
            checksum = misc.generate_hash_for_file('md5', sfile)
            misc.append_file(md5sums_file, checksum + '  .' + \
                sfile.replace(config.ISO_DIR, '') +'\n')

    # Creating a SHA256SUMS file fixes ubuntu-mini-remix's integrity check.
    shasums_file = misc.join_paths(config.ISO_DIR, 'SHA256SUMS')
    if os.path.isfile(shasums_file):
        message.sub_info('Creating SHA256SUMS')
        misc.write_file(shasums_file, '')
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith('md5sum.txt'):
                continue
            if sfile.endswith('SHA256SUMS'):
                continue
            message.sub_debug('SHA256 Checksumming', sfile)
            checksum = misc.generate_hash_for_file('sha256', sfile)
            misc.append_file(shasums_file, checksum + '  .' + \
                sfile.replace(config.ISO_DIR, '') +'\n')

    # Create the ISO filesystem
    message.sub_info('Creating ISO')
    os.chdir(config.ISO_DIR)
    misc.system_command(('xorriso', '-as', 'mkisofs', '-r', '-V', \
        distrib + '-' + arch + '-' + release, '-b', 'isolinux/isolinux.bin', \
        '-c', 'isolinux/boot.cat', '-J', '-l', '-no-emul-boot', \
        '-boot-load-size', '4', '-boot-info-table', '-o', iso_file, \
        '-cache-inodes', '-input-charset', 'utf-8', '.'))

    message.sub_info('Creating ISO checksums')
    md5checksum = misc.generate_hash_for_file('md5', iso_file)
    message.sub_info('ISO md5 checksum', md5checksum)
    misc.append_file(md5sum_iso_file, md5checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')
    sha1checksum = misc.generate_hash_for_file('sha1', iso_file)
    message.sub_info('ISO sha1 checksum', sha1checksum)
    misc.append_file(sha1sum_iso_file, sha1checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')
    sha256checksum = misc.generate_hash_for_file('sha256', iso_file)
    message.sub_info('ISO sha256 checksum', sha256checksum)
    misc.append_file(sha256sum_iso_file, sha256checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')

    message.sub_info('Successfuly created ISO image', iso_file)
Example #4
0
def main():
    common.check_filesystem()

    # Basic sanity checks of files and paths that absolutely need to exist.
    message.sub_info('Doing sanity checks')
    lsb_file = misc.join_paths(config.FILESYSTEM_DIR, 'etc/lsb-release')
    if not os.path.isfile(lsb_file):
        raise(message.exception(lsb_file + ' does not exist'))

    isolinux_dir = misc.join_paths(config.ISO_DIR, 'isolinux')
    if not os.path.isdir(isolinux_dir):
        raise(message.exception(isolinux_dir + ' does not exist'))

    if misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/passwd')):
        raise(message.exception('User with UID 999 exists, this means automatic login will fail'))
    elif misc.search_file('999:999', misc.join_paths(config.FILESYSTEM_DIR, 'etc/group')):
        raise(message.exception('Group with GID 999 exists, this means automatic login will fail'))

    casper_dir = misc.join_paths(config.ISO_DIR, 'casper')
    if not os.path.isdir(casper_dir):
        message.sub_debug('Creating', casper_dir)
        os.makedirs(casper_dir)

    base_file = misc.join_paths(config.ISO_DIR, '.disk/base_installable')
    if os.path.isfile(misc.join_paths(config.FILESYSTEM_DIR, 'usr/bin/ubiquity')):
        if not os.path.isfile(base_file):
            message.sub_debug('Creating', base_file)
            misc.write_file(base_file, '')
    elif os.path.isfile(base_file):
        message.sub_debug('Removing', base_file)
        os.unlink(base_file)

    # Acquire distribution information from the FileSystem
    message.sub_info('Gathering information')
    arch = misc.chroot_exec(('dpkg', '--print-architecture'), prepare=False, \
        mount=False, output=True)
    distrib = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_ID=')
    release = common.get_value(config.FILESYSTEM_DIR + '/etc/lsb-release', \
        'DISTRIB_RELEASE=')

    if isinstance(arch, bytes):  # For some reason this is of type 'bytes'.
        if int(sys.version_info[0]) >= 3:  # If we're running under python3
            arch = str(arch, 'utf-8')
        else:  # Otherwise just cast it to a str without the 'utf-8' option.
            arch = str(arch)

    # It's really annoying to override the output filename other ways.
    # If you actually try to change lsb-release, you end up breaking apt.
    livecd_file = misc.join_paths(config.FILESYSTEM_DIR, 'etc/livecd-release')
    if os.path.isfile(livecd_file):
        distrib = common.get_value(config.FILESYSTEM_DIR + '/etc/livecd-release', \
            'DISTRIB_ID=')
        release = common.get_value(config.FILESYSTEM_DIR + '/etc/livecd-release', \
            'DISTRIB_RELEASE=')
        message.sub_debug('Distribution and Release overriden by /etc/livecd-release')
        # Just overwrite the variables if the file actually exists, it's cleaner.

    message.sub_debug('Architecture', arch)
    message.sub_debug('Distribution (DISTRIB_ID)', distrib)
    message.sub_debug('Release (DISTRIB_RELEASE)', release)

    # Remove files, by name, that we know we must repopulate if they exist.
    message.sub_info('Cleaning up')
    cleanup_files = ['casper/filesystem.squashfs', 'casper/initrd.lz', \
        'casper/vmlinuz', 'casper/vmlinuz.efi', 'casper/filesystem.manifest', \
        'casper/filesystem.size']
    cleanup_files.extend(glob.glob('.disk/casper-uuid-*'))
    for sfile in cleanup_files:
        full_file = misc.join_paths(config.ISO_DIR, sfile)
        if os.path.exists(full_file):
            message.sub_debug('Removing', full_file)
            os.unlink(full_file)

    # Define the checksum files, and the ISO filename.
    md5sum_iso_file = misc.join_paths(config.WORK_DIR, 'md5sum')
    sha1sum_iso_file = misc.join_paths(config.WORK_DIR, 'sha1sum')
    sha256sum_iso_file = misc.join_paths(config.WORK_DIR, 'sha256sum')
    iso_file = '%s/%s-%s-%s.iso' % (config.WORK_DIR, distrib, arch, release)
    if os.path.exists(iso_file):
        message.sub_debug('Removing', iso_file)
        os.unlink(iso_file)
    if os.path.exists(md5sum_iso_file):
        message.sub_debug('Removing', md5sum_iso_file)
        os.unlink(md5sum_iso_file)
    if os.path.exists(sha1sum_iso_file):
        message.sub_debug('Removing', sha1sum_iso_file)
        os.unlink(sha1sum_iso_file)
    if os.path.exists(sha256sum_iso_file):
        message.sub_debug('Removing', sha256sum_iso_file)
        os.unlink(sha256sum_iso_file)

    # Detect files needed for booting, the kernel, initramfs, xen and anything else.
    detect_boot()
    if not vmlinuz:
        if config.PURGE_KERNEL:
            message.sub_info('Re-installing kernel')
            misc.chroot_exec(('apt-get', 'purge', '--yes', 'linux-image*', '-q'))
        message.sub_debug("Kernel Selection Debug: {0}, {1}".format(type(config.KERNEL), config.KERNEL))
        if config.KERNEL is not "default" or None:
            misc.chroot_exec(('apt-get', 'install', '--yes', \
                config.KERNEL, '-q'))
        else:  # use the kernel the user specified in the config.
            if arch is not "amd64":  # then use the 32bit 'linux-image-generic'
                misc.chroot_exec(('apt-get', 'install', '--yes', \
                    'linux-image-generic', '-q'))
            else:  # use the amd64 'linux-signed-generic' for uEFI
                misc.chroot_exec(('apt-get', 'install', '--yes', \
                    'linux-signed-generic', '-q'))

        misc.chroot_exec(('apt-get', 'clean'))
    else:
        message.sub_info('Updating initramfs')
        misc.chroot_exec(('update-initramfs', '-k', 'all', '-t', '-u'))
    detect_boot()

    if not initrd or not vmlinuz:
        raise(message.exception('Missing boot file (initrd or vmlinuz)'))
    else:
        message.sub_info('Copying boot files')
        message.sub_debug('Initrd', initrd)
        message.sub_debug('Vmlinuz', vmlinuz)
        misc.copy_file(initrd, misc.join_paths(config.ISO_DIR, 'casper/initrd.lz'))
        
        # FIXME: extend to support grub
        efi_boot_entry = False
        isolinux_dir = config.ISO_DIR + '/isolinux'
        if os.path.isdir(isolinux_dir):
            for sfile in os.listdir(isolinux_dir):
                if sfile.endswith('.cfg') and misc.search_file('vmlinuz.efi', isolinux_dir + '/' + sfile):
                    message.sub_debug('Found EFI entry in isolinux conf', sfile)
                    efi_boot_entry = True
        if os.path.isdir(misc.join_paths(config.ISO_DIR, 'efi/boot')) or \
            efi_boot_entry:
            message.sub_debug('Copying EFI vmlinuz')
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz.efi'))
            os.link(misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz.efi'), misc.join_paths(config.ISO_DIR, \
                'casper/vmlinuz'))
            # EFI Kernels are still loadable by grub, modern ISOs lack a bare vmlinuz.
            # mkisofs/genisoimage -cache-inodes reuses hard linked inodes.
        else:
            misc.copy_file(vmlinuz, misc.join_paths(config.ISO_DIR, 'casper/vmlinuz'))
            # We only need to copy the bare kernel if we're not using EFI at all.

    # Copy optional boot-enablement packages onto the ISO, if found.
    if mt86plus:
        message.sub_debug('Memtest86+ kernel', mt86plus)
        misc.copy_file(mt86plus, misc.join_paths(config.ISO_DIR, 'install/mt86plus'))
    if xen_kernel:
        message.sub_debug('Xen kernel', xen_kernel)
        misc.copy_file(xen_kernel, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(xen_kernel)))
    if xen_efi:
        message.sub_debug('Xen EFI kernel', xen_efi)
        misc.copy_file(xen_efi, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(xen_efi)))
    if ipxe_kernel:
        message.sub_debug('iPXE kernel', ipxe_kernel)
        misc.copy_file(ipxe_kernel, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(ipxe_kernel)))
    if ipxe_efi:
        message.sub_debug('iPXE EFI kernel', ipxe_efi)
        misc.copy_file(ipxe_efi, \
            misc.join_paths(config.ISO_DIR, 'casper/' + os.path.basename(ipxe_efi)))

    kernel_type = re.search('initrd.img-*.*.*-*-(.*)', initrd).group(1)
    message.sub_debug('Kernel Variant Type', kernel_type)

    message.sub_info('Extracting casper UUID')
    confdir = config.FILESYSTEM_DIR + '/conf'
    if os.path.isdir(confdir):
        shutil.rmtree(confdir)
    os.makedirs(confdir)

    if common.is_gz_file(initrd):
        message.sub_debug('Kernel Compression', "gzip without early microcode")
        try:
            misc.chroot_exec('zcat ' + initrd.replace(config.FILESYSTEM_DIR, '') + ' | cpio --quiet -id conf/uuid.conf', \
                shell=True, cwd=config.FILESYSTEM_DIR)
            misc.copy_file(confdir + '/uuid.conf', misc.join_paths(config.ISO_DIR, \
                '.disk/casper-uuid-' + kernel_type))
        finally:
            shutil.rmtree(confdir)

    else:
        message.sub_debug('Kernel Compression', "gzip with early microcode")
        try:
            misc.chroot_exec('unmkinitramfs ' + initrd.replace(config.FILESYSTEM_DIR, '') + ' conf/', \
                shell=True, cwd=config.FILESYSTEM_DIR)
            misc.copy_file(confdir + '/main/conf/uuid.conf', misc.join_paths(config.ISO_DIR, \
                '.disk/casper-uuid-' + kernel_type))
        finally:
            shutil.rmtree(confdir)

    # Define some default compression parameters, including a 1MB blocksize for all compressors.
    compression_parameters = ('-b', '1048576', '-comp', config.COMPRESSION)
    if config.COMPRESSION == 'xz':  # Append additional compression parameters for xz.
        # Using the branch-call-jump filter provides a compression boost with executable code.
        # This can save a hundred megabytes easily, on an 800MB ISO. The dictionary size must
        # match the block size, and it's advisable to use larger block sizes, like 1MB or 4MB.
        compression_parameters += ('-Xbcj', 'x86', '-Xdict-size', '100%')
    message.sub_info('SquashFS Compression parameters', compression_parameters)

    # Create the compressed filesystem
    message.sub_info('Creating SquashFS compressed filesystem')
    make_squash_fs = ('mksquashfs', config.FILESYSTEM_DIR, \
        misc.join_paths(config.ISO_DIR, 'casper/filesystem.squashfs'), \
        '-wildcards', '-no-recovery', '-noappend', \
        '-ef', os.path.join(sys.prefix, 'share/customizer/exclude.list'))
    misc.system_command(make_squash_fs + compression_parameters)

    message.sub_info('Checking SquashFS filesystem size')
    sfs_size = os.path.getsize(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.squashfs'))
    message.sub_debug('SquashFS filesystem size', sfs_size)
    if sfs_size > 4000000000:
        raise(message.exception('The SquashFS filesystem size is greater than 4GB'))

    message.sub_info('Creating filesystem.size')
    fs_size = 0
    for root, subdirs, files in os.walk(config.FILESYSTEM_DIR):
        for sfile in files:
            sfull = os.path.join(root, sfile)
            if os.path.islink(sfull):
                continue
            # FIXME: respect ignored files from exclude.list
            fs_size += os.path.getsize(sfull)
    message.sub_debug('Root filesystem size', fs_size)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.size'), str(fs_size))

    message.sub_info('Creating filesystem.manifest')
    lpackages = misc.chroot_exec(('dpkg-query', '-W', \
        '--showformat=${Package} ${Version}\\n'), prepare=False, mount=False, \
        output=True)
    if isinstance(lpackages, bytes):  # For some reason this is of type 'bytes'.
        if int(sys.version_info[0]) >= 3:  # If we're running under python3
            lpackages = str(lpackages, 'utf-8')
        else:  # Otherwise just cast it to a str without the 'utf-8' option.
            lpackages = str(lpackages)
    message.sub_debug('Packages', lpackages)
    misc.write_file(misc.join_paths(config.ISO_DIR, \
        'casper/filesystem.manifest'), lpackages)

    # FIXME: do some kung-fu to check if packages are installed
    # and remove them from filesystem.manifest-remove if they are not

    # Creating a md5sum.txt file fixes lubuntu's integrity check.
    md5sums_file = misc.join_paths(config.ISO_DIR, 'md5sum.txt')
    if os.path.isfile(md5sums_file):
        message.sub_info('Creating md5sum.txt')
        misc.write_file(md5sums_file, '')
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith('md5sum.txt'):
                continue
            if sfile.endswith('SHA256SUMS'):
                continue
            message.sub_debug('MD5 Checksumming', sfile)
            checksum = misc.generate_hash_for_file('md5', sfile)
            misc.append_file(md5sums_file, checksum + '  .' + \
                sfile.replace(config.ISO_DIR, '') +'\n')

    # Creating a SHA256SUMS file fixes ubuntu-mini-remix's integrity check.
    shasums_file = misc.join_paths(config.ISO_DIR, 'SHA256SUMS')
    if os.path.isfile(shasums_file):
        message.sub_info('Creating SHA256SUMS')
        misc.write_file(shasums_file, '')
        for sfile in misc.list_files(config.ISO_DIR):
            if sfile.endswith('md5sum.txt'):
                continue
            if sfile.endswith('SHA256SUMS'):
                continue
            message.sub_debug('SHA256 Checksumming', sfile)
            checksum = misc.generate_hash_for_file('sha256', sfile)
            misc.append_file(shasums_file, checksum + '  .' + \
                sfile.replace(config.ISO_DIR, '') +'\n')

    # Create the ISO filesystem
    message.sub_info('Creating ISO')
    os.chdir(config.ISO_DIR)
    misc.system_command(('xorriso', '-as', 'mkisofs', '-r', '-V', \
        distrib + '-' + arch + '-' + release, '-isohybrid-mbr',\
        '/usr/lib/ISOLINUX/isohdpfx.bin', '-b', 'isolinux/isolinux.bin', \
        '-c', 'isolinux/boot.cat', '-J', '-l', '-no-emul-boot', \
        '-boot-load-size', '4', '-boot-info-table', '-o', iso_file, \
        '-cache-inodes', '-input-charset', 'utf-8', '.'))

    message.sub_info('Creating ISO checksums')
    md5checksum = misc.generate_hash_for_file('md5', iso_file)
    message.sub_info('ISO md5 checksum', md5checksum)
    misc.append_file(md5sum_iso_file, md5checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')
    sha1checksum = misc.generate_hash_for_file('sha1', iso_file)
    message.sub_info('ISO sha1 checksum', sha1checksum)
    misc.append_file(sha1sum_iso_file, sha1checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')
    sha256checksum = misc.generate_hash_for_file('sha256', iso_file)
    message.sub_info('ISO sha256 checksum', sha256checksum)
    misc.append_file(sha256sum_iso_file, sha256checksum + '  .' + \
        iso_file.replace(config.WORK_DIR, '') +'\n')

    message.sub_info('Successfuly created ISO image', iso_file)