macadmin-scripts/installinstallmacos.py

#!/usr/bin/python
# encoding: utf-8
#
# Copyright 2017 Greg Neagle.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Thanks to Tim Sutton for ideas, suggestions, and sample code.
#

"""installinstallmacos.py
A tool to download the parts for an Install macOS app from Apple's
softwareupdate servers and install a functioning Install macOS app onto an
empty disk image"""

# Python 3 compatibility shims
from __future__ import absolute_import, division, print_function, unicode_literals

import argparse
import gzip
import os
import plistlib
import shutil
import subprocess
import sys
import xattr

try:
    # python 2
    from urllib.parse import urlsplit
except ImportError:
    # python 3
    from urlparse import urlsplit
from xml.dom import minidom
from xml.parsers.expat import ExpatError
from distutils.version import LooseVersion


DEFAULT_SUCATALOGS = {
    "17": "https://swscan.apple.com/content/catalogs/others/"
    "index-10.13-10.12-10.11-10.10-10.9"
    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
    "18": "https://swscan.apple.com/content/catalogs/others/"
    "index-10.14-10.13-10.12-10.11-10.10-10.9"
    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
    "19": "https://swscan.apple.com/content/catalogs/others/"
    "index-10.15-10.14-10.13-10.12-10.11-10.10-10.9"
    "-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog",
}

SEED_CATALOGS_PLIST = (
    "/System/Library/PrivateFrameworks/Seeding.framework/Versions/Current/"
    "Resources/SeedCatalogs.plist"
)


def get_board_id():
    """Gets the local system board ID"""
    ioreg_cmd = ["/usr/sbin/ioreg", "-p", "IODeviceTree", "-r", "-n", "/", "-d", "1"]
    try:
        ioreg_output = subprocess.check_output(ioreg_cmd).splitlines()
        for line in ioreg_output:
            line_decoded = line.decode("utf8")
            if "board-id" in line_decoded:
                board_id = line_decoded.split("<")[-1]
                board_id = board_id[board_id.find('<"') + 2 : board_id.find('">')]
                return board_id
    except subprocess.CalledProcessError as err:
        raise ReplicationError(err)


def is_a_vm():
    """Determines if the script is being run in a virtual machine"""
    sysctl_cmd = ["/usr/sbin/sysctl", "-n", "machdep.cpu.features"]
    try:
        sysctl_output = subprocess.check_output(sysctl_cmd)
        cpu_features = sysctl_output.decode("utf8").split(" ")
        is_vm = False
        for i in range(len(cpu_features)):
            if cpu_features[i] == "VMM":
                is_vm = True
    except subprocess.CalledProcessError as err:
        raise ReplicationError(err)
    return is_vm


def get_hw_model():
    """Gets the local system ModelIdentifier"""
    sysctl_cmd = ["/usr/sbin/sysctl", "-n", "hw.model"]
    try:
        sysctl_output = subprocess.check_output(sysctl_cmd)
        hw_model = sysctl_output.decode("utf8")
    except subprocess.CalledProcessError as err:
        raise ReplicationError(err)
    return hw_model


def get_bridge_id():
    """Gets the local system DeviceID for T2 Macs - note only works on 10.13+"""
    if os.path.exists("/usr/libexec/remotectl"):
        remotectl_cmd = [
            "/usr/libexec/remotectl",
            "get-property",
            "localbridge",
            "HWModel",
        ]
        try:
            remotectl_output = subprocess.check_output(
                remotectl_cmd, stderr=subprocess.STDOUT
            )
            bridge_id = remotectl_output.decode("utf8").split(" ")[-1].split("\n")[0]
        except subprocess.CalledProcessError:
            return None
        return bridge_id


def get_current_build_info():
    """Gets the local system build"""
    build_info = []
    sw_vers_cmd = ["/usr/bin/sw_vers"]
    try:
        sw_vers_output = subprocess.check_output(sw_vers_cmd).splitlines()
        for line in sw_vers_output:
            line_decoded = line.decode("utf8")
            if "ProductVersion" in line_decoded:
                build_info.insert(0, line_decoded.split("\t")[-1])
            if "BuildVersion" in line_decoded:
                build_info.insert(1, line_decoded.split("\t")[-1])
    except subprocess.CalledProcessError as err:
        raise ReplicationError(err)
    return build_info


def get_input(prompt=None):
    """Python 2 and 3 wrapper for raw_input/input"""
    try:
        return raw_input(prompt)
    except NameError:
        # raw_input doesn't exist in Python 3
        return input(prompt)


def read_plist(filepath):
    """Wrapper for the differences between Python 2 and Python 3's plistlib"""
    try:
        with open(filepath, "rb") as fileobj:
            return plistlib.load(fileobj)
    except AttributeError:
        # plistlib module doesn't have a load function (as in Python 2)
        return plistlib.readPlist(filepath)


def read_plist_from_string(bytestring):
    """Wrapper for the differences between Python 2 and Python 3's plistlib"""
    try:
        return plistlib.loads(bytestring)
    except AttributeError:
        # plistlib module doesn't have a load function (as in Python 2)
        return plistlib.readPlistFromString(bytestring)  # pylint: disable=no-member


def write_plist(plist_object, filepath):
    """Wrapper for the differences between Python 2 and Python 3's plistlib"""
    try:
        with open(filepath, "wb") as fileobj:
            return plistlib.dump(plist_object, fileobj)
    except AttributeError:
        # plistlib module doesn't have a load function (as in Python 2)
        return plistlib.writePlist(plist_object, filepath)


def get_seeding_program(sucatalog_url):
    """Returns a seeding program name based on the sucatalog_url"""
    try:
        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
        for key, value in seed_catalogs.items():
            if sucatalog_url == value:
                return key
        return ""
    except (OSError, IOError, ExpatError, AttributeError, KeyError) as err:
        print(err, file=sys.stderr)
        return ""


def get_seed_catalog(seedname="DeveloperSeed"):
    """Returns the developer seed sucatalog"""
    try:
        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
        return seed_catalogs.get(seedname)
    except (OSError, IOError, ExpatError, AttributeError, KeyError) as err:
        print(err, file=sys.stderr)
        return ""


def get_seeding_programs():
    """Returns the list of seeding program names"""
    try:
        seed_catalogs = read_plist(SEED_CATALOGS_PLIST)
        return list(seed_catalogs.keys())
    except (OSError, IOError, ExpatError, AttributeError, KeyError) as err:
        print(err, file=sys.stderr)
        return ""


def get_default_catalog():
    """Returns the default softwareupdate catalog for the current OS"""
    darwin_major = os.uname()[2].split(".")[0]
    return DEFAULT_SUCATALOGS.get(darwin_major)


def make_sparse_image(volume_name, output_path):
    """Make a sparse disk image we can install a product to"""
    cmd = [
        "/usr/bin/hdiutil",
        "create",
        "-size",
        "16g",
        "-fs",
        "HFS+",
        "-volname",
        volume_name,
        "-type",
        "SPARSE",
        "-plist",
        output_path,
    ]
    try:
        output = subprocess.check_output(cmd)
    except subprocess.CalledProcessError as err:
        print(err, file=sys.stderr)
        exit(-1)
    try:
        return read_plist_from_string(output)[0]
    except IndexError as err:
        print("Unexpected output from hdiutil: %s" % output, file=sys.stderr)
        exit(-1)
    except ExpatError as err:
        print("Malformed output from hdiutil: %s" % output, file=sys.stderr)
        print(err, file=sys.stderr)
        exit(-1)


def make_compressed_dmg(app_path, diskimagepath, volume_name):
    """Returns path to newly-created compressed r/o disk image containing
    Install macOS.app"""

    print(
        "Making read-only compressed disk image containing %s..."
        % os.path.basename(app_path)
    )
    cmd = [
        "/usr/bin/hdiutil",
        "create",
        "-fs",
        "HFS+",
        "-srcfolder",
        app_path,
        diskimagepath,
    ]
    try:
        subprocess.check_call(cmd)
    except subprocess.CalledProcessError as err:
        print(err, file=sys.stderr)
    else:
        print("Disk image created at: %s" % diskimagepath)


def mountdmg(dmgpath):
    """
    Attempts to mount the dmg at dmgpath and returns first mountpoint
    """
    mountpoints = []
    dmgname = os.path.basename(dmgpath)
    cmd = [
        "/usr/bin/hdiutil",
        "attach",
        dmgpath,
        "-mountRandom",
        "/tmp",
        "-nobrowse",
        "-plist",
        "-owners",
        "on",
    ]
    proc = subprocess.Popen(
        cmd, bufsize=-1, stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
    (pliststr, err) = proc.communicate()
    if proc.returncode:
        print('Error: "%s" while mounting %s.' % (err, dmgname), file=sys.stderr)
        return None
    if pliststr:
        plist = read_plist_from_string(pliststr)
        for entity in plist["system-entities"]:
            if "mount-point" in entity:
                mountpoints.append(entity["mount-point"])

    return mountpoints[0]


def unmountdmg(mountpoint):
    """
    Unmounts the dmg at mountpoint
    """
    proc = subprocess.Popen(
        ["/usr/bin/hdiutil", "detach", mountpoint],
        bufsize=-1,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
    )
    (dummy_output, err) = proc.communicate()
    if proc.returncode:
        print("Polite unmount failed: %s" % err, file=sys.stderr)
        print("Attempting to force unmount %s" % mountpoint, file=sys.stderr)
        # try forcing the unmount
        retcode = subprocess.call(["/usr/bin/hdiutil", "detach", mountpoint, "-force"])
        if retcode:
            print("Failed to unmount %s" % mountpoint, file=sys.stderr)


def install_product(dist_path, target_vol):
    """Install a product to a target volume.
    Returns a boolean to indicate success or failure."""
    # set CM_BUILD env var to make Installer bypass eligibilty checks
    # when installing packages (for machine-specific OS builds)
    os.environ["CM_BUILD"] = "CM_BUILD"
    cmd = ["/usr/sbin/installer", "-pkg", dist_path, "-target", target_vol]
    try:
        subprocess.check_call(cmd)
    except subprocess.CalledProcessError as err:
        print(err, file=sys.stderr)
        return False
    else:
        # Apple postinstall script bug ends up copying files to a path like
        # /tmp/dmg.T9ak1HApplications
        path = target_vol + "Applications"
        if os.path.exists(path):
            print("*********************************************************")
            print("*** Working around a very dumb Apple bug in a package ***")
            print("*** postinstall script that fails to correctly target ***")
            print("*** the Install macOS.app when installed to a volume  ***")
            print("*** other than the current boot volume.               ***")
            print("***       Please file feedback with Apple!            ***")
            print("*********************************************************")
            subprocess.check_call(
                ["/usr/bin/ditto", path, os.path.join(target_vol, "Applications")]
            )
            subprocess.check_call(["/bin/rm", "-r", path])
        return True


class ReplicationError(Exception):
    """A custom error when replication fails"""

    pass


def replicate_url(
    full_url,
    root_dir="/tmp",
    show_progress=False,
    ignore_cache=False,
    attempt_resume=False,
):
    """Downloads a URL and stores it in the same relative path on our
    filesystem. Returns a path to the replicated file."""

    path = urlsplit(full_url)[2]
    relative_url = path.lstrip("/")
    relative_url = os.path.normpath(relative_url)
    local_file_path = os.path.join(root_dir, relative_url)
    if show_progress:
        options = "-fL"
    else:
        options = '-sfL'
    curl_cmd = ['/usr/bin/curl', options,
                '--create-dirs',
                '-o', local_file_path]
    if not full_url.endswith(".gz"):
        # stupid hack for stupid Apple behavior where it sometimes returns
        # compressed files even when not asked for
        curl_cmd.append('--compressed')
    if not ignore_cache and os.path.exists(local_file_path):
        curl_cmd.extend(["-z", local_file_path])
        if attempt_resume:
            curl_cmd.extend(["-C", "-"])
    curl_cmd.append(full_url)
    # print("Downloading %s..." % full_url)
    try:
        subprocess.check_call(curl_cmd)
    except subprocess.CalledProcessError as err:
        raise ReplicationError(err)
    return local_file_path


def parse_server_metadata(filename):
    """Parses a softwareupdate server metadata file, looking for information
    of interest.
    Returns a dictionary containing title, version, and description."""
    title = ""
    vers = ""
    try:
        md_plist = read_plist(filename)
    except (OSError, IOError, ExpatError) as err:
        print("Error reading %s: %s" % (filename, err), file=sys.stderr)
        return {}
    vers = md_plist.get("CFBundleShortVersionString", "")
    localization = md_plist.get("localization", {})
    preferred_localization = localization.get("English") or localization.get("en")
    if preferred_localization:
        title = preferred_localization.get("title", "")

    metadata = {}
    metadata["title"] = title
    metadata["version"] = vers
    return metadata


def get_server_metadata(catalog, product_key, workdir, ignore_cache=False):
    """Replicate ServerMetaData"""
    try:
        url = catalog["Products"][product_key]["ServerMetadataURL"]
        try:
            smd_path = replicate_url(url, root_dir=workdir, ignore_cache=ignore_cache)
            return smd_path
        except ReplicationError as err:
            print("Could not replicate %s: %s" % (url, err), file=sys.stderr)
            return None
    except KeyError:
        # print("No metadata for %s.\n" % product_key, file=sys.stderr)
        return None


def parse_dist(filename):
    """Parses a softwareupdate dist file, returning a dict of info of
    interest"""
    dist_info = {}
    try:
        dom = minidom.parse(filename)
    except ExpatError:
        print("Invalid XML in %s" % filename, file=sys.stderr)
        return dist_info
    except IOError as err:
        print("Error reading %s: %s" % (filename, err), file=sys.stderr)
        return dist_info

    titles = dom.getElementsByTagName("title")
    if titles:
        dist_info["title_from_dist"] = titles[0].firstChild.wholeText

    auxinfos = dom.getElementsByTagName("auxinfo")
    if not auxinfos:
        return dist_info
    auxinfo = auxinfos[0]
    key = None
    value = None
    children = auxinfo.childNodes
    # handle the possibility that keys from auxinfo may be nested
    # within a 'dict' element
    dict_nodes = [
        n
        for n in auxinfo.childNodes
        if n.nodeType == n.ELEMENT_NODE and n.tagName == "dict"
    ]
    if dict_nodes:
        children = dict_nodes[0].childNodes
    for node in children:
        if node.nodeType == node.ELEMENT_NODE and node.tagName == "key":
            key = node.firstChild.wholeText
        if node.nodeType == node.ELEMENT_NODE and node.tagName == "string":
            value = node.firstChild.wholeText
        if key and value:
            dist_info[key] = value
            key = None
            value = None
    return dist_info


def get_board_ids(filename):
    """Parses a softwareupdate dist file, returning a list of supported
    Board IDs"""
    supported_board_ids = ""
    with open(filename) as search:
        for line in search:
            line = line.decode("utf8").rstrip()  # remove '\n' at end of line
            # dist files for macOS 10.* list boardIDs whereas dist files for
            # macOS 11.* list supportedBoardIDs
            if "boardIds" in line:
                supported_board_ids = line.lstrip("var boardIDs = ")
            elif "supportedBoardIDs" in line:
                supported_board_ids = line.lstrip("var supportedBoardIDs = ")
                return supported_board_ids


def get_device_ids(filename):
    """Parses a softwareupdate dist file, returning a list of supported
    Device IDs. These are used for identifying T2 chips in the dist files of macOS 11.* - not checked in older builds"""
    supported_device_ids = ""
    with open(filename) as search:
        for line in search:
            line = line.decode("utf8").rstrip()  # remove '\n' at end of line
            if "supportedDeviceIDs" in line:
                supported_device_ids = line.lstrip("var supportedDeviceIDs = ")
                return supported_device_ids


def get_unsupported_models(filename):
    """Parses a softwareupdate dist file, returning a list of non-supported
    ModelIdentifiers. This is not used in macOS 11.*"""
    unsupported_models = ""
    with open(filename) as search:
        for line in search:
            line = line.decode("utf8").rstrip()  # remove '\n' at end of line
            if "nonSupportedModels" in line:
                unsupported_models = line.lstrip("var nonSupportedModels = ")
                return unsupported_models


def download_and_parse_sucatalog(sucatalog, workdir, ignore_cache=False):
    """Downloads and returns a parsed softwareupdate catalog"""
    try:
        localcatalogpath = replicate_url(
            sucatalog, root_dir=workdir, ignore_cache=ignore_cache
        )
    except ReplicationError as err:
        print("Could not replicate %s: %s" % (sucatalog, err), file=sys.stderr)
        exit(-1)
    if os.path.splitext(localcatalogpath)[1] == ".gz":
        with gzip.open(localcatalogpath) as the_file:
            content = the_file.read()
            try:
                catalog = read_plist_from_string(content)
                return catalog
            except ExpatError as err:
                print("Error reading %s: %s" % (localcatalogpath, err), file=sys.stderr)
                exit(-1)
    else:
        try:
            catalog = read_plist(localcatalogpath)
            return catalog
        except (OSError, IOError, ExpatError) as err:
            print("Error reading %s: %s" % (localcatalogpath, err), file=sys.stderr)
            exit(-1)


def find_mac_os_installers(catalog):
    """Return a list of product identifiers for what appear to be macOS
    installers"""
    mac_os_installer_products = []
    if "Products" in catalog:
        for product_key in catalog["Products"].keys():
            product = catalog["Products"][product_key]
            try:
                if product["ExtendedMetaInfo"]["InstallAssistantPackageIdentifiers"]:
                    mac_os_installer_products.append(product_key)
            except KeyError:
                continue
    return mac_os_installer_products


def os_installer_product_info(catalog, workdir, ignore_cache=False):
    """Returns a dict of info about products that look like macOS installers"""
    product_info = {}
    installer_products = find_mac_os_installers(catalog)
    for product_key in installer_products:
        product_info[product_key] = {}
        # get the localized title (e.g. "macOS Catalina Beta") and version
        # from ServerMetadataURL for macOS 10.*
        # For macOS 11.* we get these directly from the dist file
        filename = get_server_metadata(catalog, product_key, workdir)
        if filename:
            product_info[product_key] = parse_server_metadata(filename)
        else:
            product_info[product_key]["title"] = None
            product_info[product_key]["version"] = None

        product = catalog["Products"][product_key]
        product_info[product_key]["PostDate"] = product["PostDate"]
        distributions = product["Distributions"]
        dist_url = distributions.get("English") or distributions.get("en")
        try:
            dist_path = replicate_url(
                dist_url, root_dir=workdir, ignore_cache=ignore_cache
            )
        except ReplicationError as err:
            print("Could not replicate %s: %s" % (dist_url, err), file=sys.stderr)
        else:
            dist_info = parse_dist(dist_path)
            product_info[product_key]["DistributionPath"] = dist_path
            unsupported_models = get_unsupported_models(dist_path)
            product_info[product_key]["UnsupportedModels"] = unsupported_models
            board_ids = get_board_ids(dist_path)
            product_info[product_key]["BoardIDs"] = board_ids
            device_ids = get_device_ids(dist_path)
            product_info[product_key]["DeviceIDs"] = device_ids
            product_info[product_key].update(dist_info)
            if not product_info[product_key]["title"]:
                product_info[product_key]["title"] = dist_info.get("title_from_dist")
            if not product_info[product_key]["version"]:
                product_info[product_key]["version"] = dist_info.get("VERSION")

    return product_info


def get_latest_version(current_item, latest_item):
    """Compares versions between two values and returns the latest (highest) value"""
    if LooseVersion(current_item) > LooseVersion(latest_item):
        return current_item
    else:
        return latest_item


def replicate_product(catalog, product_id, workdir, ignore_cache=False):
    """Downloads all the packages for a product"""
    product = catalog["Products"][product_id]
    for package in product.get("Packages", []):
        # TO-DO: Check 'Size' attribute and make sure
        # we have enough space on the target
        # filesystem before attempting to download
        if "URL" in package:
            try:
                replicate_url(
                    package["URL"],
                    root_dir=workdir,
                    show_progress=True,
                    ignore_cache=ignore_cache,
                    attempt_resume=(not ignore_cache),
                )
            except ReplicationError as err:
                print(
                    "Could not replicate %s: %s" % (package["URL"], err),
                    file=sys.stderr,
                )
                exit(-1)
        if "MetadataURL" in package:
            try:
                replicate_url(
                    package["MetadataURL"], root_dir=workdir, ignore_cache=ignore_cache
                )
            except ReplicationError as err:
                print(
                    "Could not replicate %s: %s" % (package["MetadataURL"], err),
                    file=sys.stderr,
                )
                exit(-1)


def find_installer_app(mountpoint):
    """Returns the path to the Install macOS app on the mountpoint"""
    applications_dir = os.path.join(mountpoint, "Applications")
    for item in os.listdir(applications_dir):
        if item.endswith(".app"):
            return os.path.join(applications_dir, item)
    return None


def main():
    """Do the main thing here"""

    print(
        "\n"
        "installinstallmacos.py - get macOS installers "
        "from the Apple software catalog"
        "\n"
    )

    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--seedprogram",
        default="",
        help="Which Seed Program catalog to use. Valid values "
        "are %s." % ", ".join(get_seeding_programs()),
    )
    parser.add_argument(
        "--catalogurl",
        default="",
        help="Software Update catalog URL. This option "
        "overrides any seedprogram option.",
    )
    parser.add_argument(
        "--workdir",
        metavar="path_to_working_dir",
        default=".",
        help="Path to working directory on a volume with over "
        "10G of available space. Defaults to current working "
        "directory.",
    )
    parser.add_argument(
        "--clear",
        action="store_true",
        help="Clear the working directory to ensure a new download.",
    )
    parser.add_argument(
        "--compress",
        action="store_true",
        help="Output a read-only compressed disk image with "
        "the Install macOS app at the root. This is now the "
        "default. Use --raw to get a read-write sparse image "
        "with the app in the Applications directory.",
    )
    parser.add_argument(
        "--raw",
        action="store_true",
        help="Output a read-write sparse image "
        "with the app in the Applications directory. Requires "
        "less available disk space and is faster.",
    )
    parser.add_argument(
        "--ignore-cache",
        action="store_true",
        help="Ignore any previously cached files.",
    )
    parser.add_argument(
        "--build",
        metavar="build_version",
        default="",
        help="Specify a specific build to search for and " "download.",
    )
    parser.add_argument(
        "--list",
        action="store_true",
        help="Output the available updates to a plist " "and quit.",
    )
    parser.add_argument(
        "--current",
        action="store_true",
        help="Automatically select the current installed " "build.",
    )
    parser.add_argument(
        "--renew",
        action="store_true",
        help="Automatically select the appropriate valid build "
        "for the current device, limited to versions newer "
        "than the current installed build.",
    )
    parser.add_argument(
        "--newer_than_version",
        metavar="newer_than_version",
        default="",
        help="Specify a minimum version to check for newer " "versions to download.",
    )
    parser.add_argument(
        "--validate",
        action="store_true",
        help="Validate builds for board ID and hardware model "
        "and only show appropriate builds.",
    )
    parser.add_argument(
        "--auto",
        action="store_true",
        help="Automatically select the appropriate valid build "
        "for the current device.",
    )
    parser.add_argument(
        "--warnings", action="store_true", help="Show warnings in the listed output",
    )
    parser.add_argument(
        "--beta",
        action="store_true",
        help="Include beta versions in the selection "
        "(in conjunction with --auto, --os or --version)",
    )
    parser.add_argument(
        "--version",
        metavar="match_version",
        default="",
        help="Selects the latest valid build ID matching "
        "the selected version (e.g. 10.14.3).",
    )
    parser.add_argument(
        "--os",
        metavar="match_os",
        default="",
        help="Selects the latest valid build ID matching "
        "the selected OS version (e.g. 10.14).",
    )
    args = parser.parse_args()

    # show this Mac's info
    hw_model = get_hw_model()
    board_id = get_board_id()
    bridge_id = get_bridge_id()
    build_info = get_current_build_info()
    is_vm = is_a_vm()

    print("This Mac:")
    if is_vm == True:
        print("Identified as a Virtual Machine")
    print("%-17s: %s" % ("Model Identifier", hw_model))
    print("%-17s: %s" % ("Bridge ID", bridge_id))
    print("%-17s: %s" % ("Board ID", board_id))
    print("%-17s: %s" % ("OS Version", build_info[0]))
    print("%-17s: %s\n" % ("Build ID", build_info[1]))

    if os.getuid() != 0:
        sys.exit(
            "This command requires root (to install packages), so please "
            "run again with sudo or as root."
        )

    current_dir = os.getcwd()
    if os.path.expanduser("~") in current_dir:
        bad_dirs = ["Documents", "Desktop", "Downloads", "Library"]
        for bad_dir in bad_dirs:
            if bad_dir in os.path.split(current_dir):
                print('Running this script from %s may not work as expected. '
                      'If this does not run as expected, please run again from '
                      'somewhere else, such as /Users/Shared.'
                      % current_dir, file=sys.stderr)

    if args.catalogurl:
        su_catalog_url = args.catalogurl
    elif args.seedprogram:
        su_catalog_url = get_seed_catalog(args.seedprogram)
        if not su_catalog_url:
            print(
                "Could not find a catalog url for seed program %s" % args.seedprogram,
                file=sys.stderr,
            )
            print(
                "Valid seeding programs are: %s" % ", ".join(get_seeding_programs()),
                file=sys.stderr,
            )
            exit(-1)
    else:
        su_catalog_url = get_default_catalog()
        if not su_catalog_url:
            print(
                "Could not find a default catalog url for this OS version.",
                file=sys.stderr,
            )
            exit(-1)

    # download sucatalog and look for products that are for macOS installers
    catalog = download_and_parse_sucatalog(
        su_catalog_url, args.workdir, ignore_cache=args.ignore_cache
    )
    product_info = os_installer_product_info(
        catalog, args.workdir, ignore_cache=args.ignore_cache
    )
    if not product_info:
        print("No macOS installer products found in the sucatalog.", file=sys.stderr)
        exit(-1)

    output_plist = "%s/softwareupdate.plist" % args.workdir
    pl = {}
    pl["result"] = []

    valid_build_found = False

    # display a menu of choices (some seed catalogs have multiple installers)
    validity_header = ""
    if args.warnings:
        validity_header = "Notes/Warnings"
    print(
        "%2s  %-15s %-10s %-8s %-11s %-30s %s"
        % ("#", "ProductID", "Version", "Build", "Post Date", "Title", validity_header)
    )
    # this is where we do checks for validity based on model type and version
    for index, product_id in enumerate(product_info):
        not_valid = ""
        if is_vm == False:
            # first look for a BoardID (not present in modern hardware)
            if board_id and product_info[product_id]["BoardIDs"]:
                if board_id not in product_info[product_id]["BoardIDs"]:
                    not_valid = "Unsupported Board ID"
            # if there's no Board ID there has to be a BridgeID:
            elif bridge_id and product_info[product_id]["DeviceIDs"]:
                if bridge_id not in product_info[product_id]["DeviceIDs"]:
                    not_valid = "Unsupported Bridge ID"
            # finally we fall back on ModelIdentifiers for T1 and older
            elif hw_model and product_info[product_id]["UnsupportedModels"]:
                if hw_model in product_info[product_id]["UnsupportedModels"]:
                    not_valid = "Unsupported Model Identifier"
            # if we don't have any of those matches, then we can't do a comparison
            else:
                not_valid = "No supported model data"
        if (
            get_latest_version(build_info[0], product_info[product_id]["version"])
            != product_info[product_id]["version"]
        ):
            not_valid = "Unsupported macOS version"
        else:
            valid_build_found = True

        validity_info = ""
        if args.warnings:
            validity_info = not_valid

        print(
            "%2s  %-15s %-10s %-8s %-11s %-30s %s"
            % (
                index + 1,
                product_id,
                product_info[product_id].get("version", "UNKNOWN"),
                product_info[product_id].get("BUILD", "UNKNOWN"),
                product_info[product_id]["PostDate"].strftime("%Y-%m-%d"),
                product_info[product_id]["title"],
                validity_info,
            )
        )

        # go through various options for automatically determining the answer:

        # skip if build is not suitable for current device
        # and a validation parameter was chosen
        if not_valid and (
            args.validate
            or (args.auto or args.version or args.os)
            # and not args.beta  # not needed now we have DeviceID check
        ):
            continue

        # skip if a version is selected and it does not match
        if args.version and args.version != product_info[product_id]["version"]:
            continue

        # skip if an OS is selected and it does not match
        if args.os:
            major = product_info[product_id]["version"].split(".", 2)[:2]
            os_version = ".".join(major)
            if args.os != os_version:
                continue

        # determine the latest valid build ID and select this
        # when using auto, os and version options
        if args.auto or args.version or args.os:
            if args.beta or "Beta" not in product_info[product_id]["title"]:
                try:
                    latest_valid_build
                except NameError:
                    latest_valid_build = product_info[product_id]["BUILD"]
                    # if using newer-than option, skip if not newer than the version
                    #  we are checking against
                    if args.newer_than_version:
                        latest_valid_build = get_latest_version(
                            product_info[product_id]["version"], args.newer_than_version
                        )
                        if latest_valid_build == args.newer_than_version:
                            continue
                    # if using renew option, skip if the same as the current version
                    if (
                        args.renew
                        and build_info[0] == product_info[product_id]["version"]
                    ):
                        continue
                    answer = index + 1
                else:
                    latest_valid_build = get_latest_version(
                        product_info[product_id]["BUILD"], latest_valid_build
                    )
                    if latest_valid_build == product_info[product_id]["BUILD"]:
                        # if using newer-than option, skip if not newer than the version
                        #  we are checking against
                        if args.newer_than_version:
                            latest_valid_build = get_latest_version(
                                product_info[product_id]["version"],
                                args.newer_than_version,
                            )
                            if latest_valid_build == args.newer_than_version:
                                continue
                        # if using renew option, skip if the same as the current version
                        if (
                            args.renew
                            and build_info[1] == product_info[product_id]["BUILD"]
                        ):
                            continue
                        answer = index + 1

        # Write this build info to plist
        pl_index = {
            "index": index + 1,
            "product_id": product_id,
            "version": product_info[product_id]["version"],
            "build": product_info[product_id]["BUILD"],
            "title": product_info[product_id]["title"],
        }
        pl["result"].append(pl_index)

        if args.build:
            # automatically select matching build ID if build option used
            if args.build == product_info[product_id]["BUILD"]:
                answer = index + 1
                break

        elif args.current:
            # automatically select matching build ID if current option used
            if build_info[0] == product_info[product_id]["version"]:
                answer = index + 1
                break

    # Stop here if no valid builds found
    if (
        valid_build_found == False
        and not args.build
        and not args.current
        and not args.validate
        and not args.list
    ):
        print("No valid build found for this hardware")
        exit(0)

    # clear content directory in workdir if requested
    if args.clear:
        print(
            "Removing existing content from working directory '%s'...\n" % args.workdir
        )
        shutil.rmtree("%s/content" % args.workdir)

    # Output a plist of available updates and quit if list option chosen
    if args.list:
        write_plist(pl, output_plist)
        print("\nValid seeding programs are: %s\n" % ", ".join(get_seeding_programs()))
        exit(0)

    # check for validity of specified build if argument supplied
    if args.build:
        try:
            answer
        except NameError:
            print(
                "\n"
                "Build %s is not available. "
                "Run again without --build argument "
                "to select a valid build to download "
                "or run without --validate option to download anyway.\n" % args.build
            )
            exit(0)
        else:
            print(
                "\n" "Build %s available. Downloading #%s...\n" % (args.build, answer)
            )
    elif args.current:
        try:
            answer
        except NameError:
            print(
                "\n"
                "Build %s is not available. "
                "Run again without --current argument "
                "to select a valid build to download.\n" % build_info[0]
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s available. Downloading #%s...\n" % (build_info[0], answer)
            )
    elif args.newer_than_version:
        try:
            answer
        except NameError:
            print(
                "\n"
                "No newer valid version than the specified version available. "
                "Run again without --newer_than_version argument "
                "to select a valid build to download.\n"
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s selected. Downloading #%s...\n" % (latest_valid_build, answer)
            )
    elif args.renew:
        try:
            answer
        except NameError:
            print(
                "\n"
                "No newer valid version than the current system version available. "
                "Run again without --renew argument "
                "to select a valid build to download.\n"
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s selected. Downloading #%s...\n" % (latest_valid_build, answer)
            )
    elif args.version:
        try:
            answer
        except NameError:
            print(
                "\n"
                "Version %s is not available. "
                "Run again without --version argument "
                "to select a valid build to download.\n" % args.version
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s selected. Downloading #%s...\n" % (latest_valid_build, answer)
            )
    elif args.os:
        try:
            answer
        except NameError:
            print(
                "\n"
                "OS %s is not available. "
                "Run again without --os argument "
                "to select a valid build to download.\n" % args.os
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s selected. Downloading #%s...\n" % (latest_valid_build, answer)
            )
    elif args.auto:
        try:
            answer
        except NameError:
            print(
                "\n"
                "No valid version available. "
                "Run again without --auto argument "
                "to select a valid build to download.\n"
            )
            exit(0)
        else:
            print(
                "\n"
                "Build %s selected. Downloading #%s...\n" % (latest_valid_build, answer)
            )
    else:
        # default option to interactively offer selection
        answer = get_input(
            "\nChoose a product to download (1-%s): " % len(product_info)
        )

    try:
        index = int(answer) - 1
        if index < 0:
            raise ValueError
        product_id = list(product_info.keys())[index]
    except (ValueError, IndexError):
        print("Exiting.")
        exit(0)

    # download all the packages for the selected product
    replicate_product(catalog, product_id, args.workdir, ignore_cache=args.ignore_cache)

    # generate a name for the sparseimage
    volname = "Install_macOS_%s-%s" % (
        product_info[product_id]["version"],
        product_info[product_id]["BUILD"],
    )
    sparse_diskimage_path = os.path.join(args.workdir, volname + ".sparseimage")
    if os.path.exists(sparse_diskimage_path):
        os.unlink(sparse_diskimage_path)

    # make an empty sparseimage and mount it
    print("Making empty sparseimage...")
    sparse_diskimage_path = make_sparse_image(volname, sparse_diskimage_path)
    mountpoint = mountdmg(sparse_diskimage_path)
    if mountpoint:
        # install the product to the mounted sparseimage volume
        success = install_product(
            product_info[product_id]["DistributionPath"], mountpoint
        )
        if not success:
            print("Product installation failed.", file=sys.stderr)
            unmountdmg(mountpoint)
            exit(-1)
        # add the seeding program xattr to the app if applicable
        seeding_program = get_seeding_program(su_catalog_url)
        if seeding_program:
            installer_app = find_installer_app(mountpoint)
            if installer_app:
                print(
                    "Adding seeding program %s extended attribute to app"
                    % seeding_program
                )
                xattr.setxattr(installer_app, "SeedProgram", seeding_program.encode())
        print("Product downloaded and installed to %s" % sparse_diskimage_path)
        if args.raw:
            unmountdmg(mountpoint)
        else:
            # if --raw option not given, create a r/o compressed diskimage
            # containing the Install macOS app
            compressed_diskimagepath = os.path.join(args.workdir, volname + ".dmg")
            if os.path.exists(compressed_diskimagepath):
                os.unlink(compressed_diskimagepath)
            app_path = find_installer_app(mountpoint)
            if app_path:
                make_compressed_dmg(app_path, compressed_diskimagepath, volname)
            # unmount sparseimage
            unmountdmg(mountpoint)
            # delete sparseimage since we don't need it any longer
            os.unlink(sparse_diskimage_path)


if __name__ == "__main__":
    main()