source: vbox/trunk/src/VBox/Main/xml/Settings.cpp@ 98187

/* $Id: Settings.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
/** @file
 * Settings File Manipulation API.
 *
 * Two classes, MainConfigFile and MachineConfigFile, represent the VirtualBox.xml and
 * machine XML files. They share a common ancestor class, ConfigFileBase, which shares
 * functionality such as talking to the XML back-end classes and settings version management.
 *
 * The code can read all VirtualBox settings files version 1.3 and higher. That version was
 * written by VirtualBox 2.0. It can write settings version 1.7 (used by VirtualBox 2.2 and
 * 3.0) and 1.9 (used by VirtualBox 3.1) and newer ones obviously.
 *
 * The settings versions enum is defined in src/VBox/Main/idl/VirtualBox.xidl. To introduce
 * a new settings version (should be necessary at most once per VirtualBox major release,
 * if at all), add a new SettingsVersion value to that enum and grep for the previously
 * highest value to see which code in here needs adjusting.
 *
 * Certainly ConfigFileBase::ConfigFileBase() will. Change VBOX_XML_VERSION below as well.
 * VBOX_XML_VERSION does not have to be changed if the settings for a default VM do not
 * touch newly introduced attributes or tags. It has the benefit that older VirtualBox
 * versions do not trigger their "newer" code path.
 *
 * Once a new settings version has been added, these are the rules for introducing a new
 * setting: If an XML element or attribute or value is introduced that was not present in
 * previous versions, then settings version checks need to be introduced. See the
 * SettingsVersion enumeration in src/VBox/Main/idl/VirtualBox.xidl for details about which
 * version was used when.
 *
 * The settings versions checks are necessary because since version 3.1, VirtualBox no longer
 * automatically converts XML settings files but only if necessary, that is, if settings are
 * present that the old format does not support. If we write an element or attribute to a
 * settings file of an older version, then an old VirtualBox (before 3.1) will attempt to
 * validate it with XML schema, and that will certainly fail.
 *
 * So, to introduce a new setting:
 *
 *   1) Make sure the constructor of corresponding settings structure has a proper default.
 *
 *   2) In the settings reader method, try to read the setting; if it's there, great, if not,
 *      the default value will have been set by the constructor. The rule is to be tolerant
 *      here.
 *
 *   3) In MachineConfigFile::bumpSettingsVersionIfNeeded(), check if the new setting has
 *      a non-default value (i.e. that differs from the constructor). If so, bump the
 *      settings version to the current version so the settings writer (4) can write out
 *      the non-default value properly.
 *
 *      So far a corresponding method for MainConfigFile has not been necessary since there
 *      have been no incompatible changes yet.
 *
 *   4) In the settings writer method, write the setting _only_ if the current settings
 *      version (stored in m->sv) is high enough. That is, for VirtualBox 4.0, write it
 *      only if (m->sv >= SettingsVersion_v1_11).
 *
 *   5) You _must_ update xml/VirtualBox-settings.xsd to contain the new tags and attributes.
 *      Check that settings file from before and after your change are validating properly.
 *      Use "kmk testvalidsettings", it should not find any files which don't validate.
 */

/*
 * Copyright (C) 2007-2023 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.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, in version 3 of the
 * License.
 *
 * 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 <https://www.gnu.org/licenses>.
 *
 * SPDX-License-Identifier: GPL-3.0-only
 */

#define LOG_GROUP LOG_GROUP_MAIN
#include "VBox/com/string.h"
#include "VBox/settings.h"
#include <iprt/base64.h>
#include <iprt/cpp/lock.h>
#include <iprt/cpp/utils.h>
#include <iprt/cpp/xml.h>
#include <iprt/ctype.h>
#include <iprt/err.h>
#include <iprt/file.h>
#include <iprt/ldr.h>
#include <iprt/process.h>
#include <iprt/stream.h>
#ifdef RT_OS_WINDOWS
# include <iprt/system.h> /* For RTSystemGetNtVersion() / RTSYSTEM_MAKE_NT_VERSION. */
#endif
#include <iprt/uri.h>

// Guest Properties validation.
#include "VBox/HostServices/GuestPropertySvc.h"

// generated header
#include "SchemaDefs.h"

#include "HashedPw.h"
#include "LoggingNew.h"

using namespace com;
using namespace settings;

////////////////////////////////////////////////////////////////////////////////
//
// Defines
//
////////////////////////////////////////////////////////////////////////////////

/** VirtualBox XML settings namespace */
#define VBOX_XML_NAMESPACE      "http://www.virtualbox.org/"

/** VirtualBox XML schema location (relative URI) */
#define VBOX_XML_SCHEMA "VirtualBox-settings.xsd"

/** VirtualBox XML settings version number substring ("x.y")  */
#define VBOX_XML_VERSION        "1.12"

/** VirtualBox OVF settings import default version number substring ("x.y").
 *
 * Think twice before changing this, as all VirtualBox versions before 5.1
 * wrote the settings version when exporting, but totally ignored it on
 * importing (while it should have been a mandatory attribute), so 3rd party
 * software out there creates OVF files with the VirtualBox specific settings
 * but lacking the version attribute. This shouldn't happen any more, but
 * breaking existing OVF files isn't nice. */
#define VBOX_XML_IMPORT_VERSION "1.15"

/** VirtualBox XML settings version platform substring */
#if defined (RT_OS_DARWIN)
#   define VBOX_XML_PLATFORM     "macosx"
#elif defined (RT_OS_FREEBSD)
#   define VBOX_XML_PLATFORM     "freebsd"
#elif defined (RT_OS_LINUX)
#   define VBOX_XML_PLATFORM     "linux"
#elif defined (RT_OS_NETBSD)
#   define VBOX_XML_PLATFORM     "netbsd"
#elif defined (RT_OS_OPENBSD)
#   define VBOX_XML_PLATFORM     "openbsd"
#elif defined (RT_OS_OS2)
#   define VBOX_XML_PLATFORM     "os2"
#elif defined (RT_OS_SOLARIS)
#   define VBOX_XML_PLATFORM     "solaris"
#elif defined (RT_OS_WINDOWS)
#   define VBOX_XML_PLATFORM     "windows"
#else
#   error Unsupported platform!
#endif

/** VirtualBox XML settings full version string ("x.y-platform") */
#define VBOX_XML_VERSION_FULL   VBOX_XML_VERSION "-" VBOX_XML_PLATFORM

/** VirtualBox OVF import default settings full version string ("x.y-platform") */
#define VBOX_XML_IMPORT_VERSION_FULL   VBOX_XML_IMPORT_VERSION "-" VBOX_XML_PLATFORM

////////////////////////////////////////////////////////////////////////////////
//
// Internal data
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Opaque data structore for ConfigFileBase (only declared
 * in header, defined only here).
 */

struct ConfigFileBase::Data
{
    Data()
        : pDoc(NULL),
          pelmRoot(NULL),
          sv(SettingsVersion_Null),
          svRead(SettingsVersion_Null)
    {}

    ~Data()
    {
        cleanup();
    }

    RTCString               strFilename;
    bool                    fFileExists;

    xml::Document           *pDoc;
    xml::ElementNode        *pelmRoot;

    com::Utf8Str            strSettingsVersionFull;     // e.g. "1.7-linux"
    SettingsVersion_T       sv;                         // e.g. SettingsVersion_v1_7

    SettingsVersion_T       svRead;                     // settings version that the original file had when it was read,
                                                        // or SettingsVersion_Null if none

    void copyFrom(const Data &d)
    {
        strFilename = d.strFilename;
        fFileExists = d.fFileExists;
        strSettingsVersionFull = d.strSettingsVersionFull;
        sv = d.sv;
        svRead = d.svRead;
    }

    void cleanup()
    {
        if (pDoc)
        {
            delete pDoc;
            pDoc = NULL;
            pelmRoot = NULL;
        }
    }
};

/**
 * Private exception class (not in the header file) that makes
 * throwing xml::LogicError instances easier. That class is public
 * and should be caught by client code.
 */
class settings::ConfigFileError : public xml::LogicError
{
public:
    ConfigFileError(const ConfigFileBase *file,
                    const xml::Node *pNode,
                    const char *pcszFormat, ...)
        : xml::LogicError()
    {
        va_list args;
        va_start(args, pcszFormat);
        Utf8Str strWhat(pcszFormat, args);
        va_end(args);

        Utf8Str strLine;
        if (pNode)
            strLine = Utf8StrFmt(" (line %RU32)", pNode->getLineNumber());

        const char *pcsz = strLine.c_str();
        Utf8StrFmt str(N_("Error in %s%s -- %s"),
                       file->m->strFilename.c_str(),
                       (pcsz) ? pcsz : "",
                       strWhat.c_str());

        setWhat(str.c_str());
    }
};

////////////////////////////////////////////////////////////////////////////////
//
// ConfigFileBase
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Constructor. Allocates the XML internals, parses the XML file if
 * pstrFilename is != NULL and reads the settings version from it.
 * @param pstrFilename
 */
ConfigFileBase::ConfigFileBase(const com::Utf8Str *pstrFilename)
    : m(new Data)
{
    m->fFileExists = false;

    if (pstrFilename)
    {
        try
        {
            // reading existing settings file:
            m->strFilename = *pstrFilename;

            xml::XmlFileParser parser;
            m->pDoc = new xml::Document;
            parser.read(*pstrFilename,
                        *m->pDoc);

            m->fFileExists = true;

            m->pelmRoot = m->pDoc->getRootElement();
            if (!m->pelmRoot || !m->pelmRoot->nameEquals("VirtualBox"))
                throw ConfigFileError(this, m->pelmRoot, N_("Root element in VirtualBox settings files must be \"VirtualBox\""));

            if (!(m->pelmRoot->getAttributeValue("version", m->strSettingsVersionFull)))
                throw ConfigFileError(this, m->pelmRoot, N_("Required VirtualBox/@version attribute is missing"));

            LogRel(("Loading settings file \"%s\" with version \"%s\"\n", m->strFilename.c_str(), m->strSettingsVersionFull.c_str()));

            m->sv = parseVersion(m->strSettingsVersionFull, m->pelmRoot);

            // remember the settings version we read in case it gets upgraded later,
            // so we know when to make backups
            m->svRead = m->sv;
        }
        catch(...)
        {
            /*
             * The destructor is not called when an exception is thrown in the constructor,
             * so we have to do the cleanup here.
             */
            delete m;
            m = NULL;
            throw;
        }
    }
    else
    {
        // creating new settings file:
        m->strSettingsVersionFull = VBOX_XML_VERSION_FULL;
        m->sv = SettingsVersion_v1_12;
    }
}

ConfigFileBase::ConfigFileBase(const ConfigFileBase &other)
    : m(new Data)
{
    copyBaseFrom(other);
    m->strFilename = "";
    m->fFileExists = false;
}

/**
 * Clean up.
 */
ConfigFileBase::~ConfigFileBase()
{
    if (m)
    {
        delete m;
        m = NULL;
    }
}

/**
 * Helper function to convert a MediaType enum value into string from.
 * @param t
 */
/*static*/
const char *ConfigFileBase::stringifyMediaType(MediaType t)
{
    switch (t)
    {
        case HardDisk:
            return "hard disk";
        case DVDImage:
            return "DVD";
        case FloppyImage:
            return "floppy";
        default:
            AssertMsgFailed(("media type %d\n", t));
            return "UNKNOWN";
    }
}

/**
 * Helper function that parses a full version number.
 *
 * Allow future versions but fail if file is older than 1.6. Throws on errors.
 * @returns settings version
 * @param strVersion
 * @param pElm
 */
SettingsVersion_T ConfigFileBase::parseVersion(const Utf8Str &strVersion, const xml::ElementNode *pElm)
{
    SettingsVersion_T sv = SettingsVersion_Null;
    if (strVersion.length() > 3)
    {
        const char *pcsz = strVersion.c_str();

        uint32_t uMajor = 0;
        char ch;
        while (   (ch = *pcsz)
               && RT_C_IS_DIGIT(ch) )
        {
            uMajor *= 10;
            uMajor += (uint32_t)(ch - '0');
            ++pcsz;
        }

        uint32_t uMinor = 0;
        if (ch == '.')
        {
            pcsz++;
            while (   (ch = *pcsz)
                   && RT_C_IS_DIGIT(ch))
            {
                uMinor *= 10;
                uMinor += (ULONG)(ch - '0');
                ++pcsz;
            }
        }

        if (uMajor == 1)
        {
            if (uMinor == 3)
                sv = SettingsVersion_v1_3;
            else if (uMinor == 4)
                sv = SettingsVersion_v1_4;
            else if (uMinor == 5)
                sv = SettingsVersion_v1_5;
            else if (uMinor == 6)
                sv = SettingsVersion_v1_6;
            else if (uMinor == 7)
                sv = SettingsVersion_v1_7;
            else if (uMinor == 8)
                sv = SettingsVersion_v1_8;
            else if (uMinor == 9)
                sv = SettingsVersion_v1_9;
            else if (uMinor == 10)
                sv = SettingsVersion_v1_10;
            else if (uMinor == 11)
                sv = SettingsVersion_v1_11;
            else if (uMinor == 12)
                sv = SettingsVersion_v1_12;
            else if (uMinor == 13)
                sv = SettingsVersion_v1_13;
            else if (uMinor == 14)
                sv = SettingsVersion_v1_14;
            else if (uMinor == 15)
                sv = SettingsVersion_v1_15;
            else if (uMinor == 16)
                sv = SettingsVersion_v1_16;
            else if (uMinor == 17)
                sv = SettingsVersion_v1_17;
            else if (uMinor == 18)
                sv = SettingsVersion_v1_18;
            else if (uMinor == 19)
                sv = SettingsVersion_v1_19;
            else if (uMinor > 19)
                sv = SettingsVersion_Future;
        }
        else if (uMajor > 1)
            sv = SettingsVersion_Future;

        Log(("Parsed settings version %d.%d to enum value %d\n", uMajor, uMinor, sv));
    }

    if (sv == SettingsVersion_Null)
        throw ConfigFileError(this, pElm, N_("Cannot handle settings version '%s'"), strVersion.c_str());

    return sv;
}

/**
 * Helper function that parses a UUID in string form into
 * a com::Guid item. Accepts UUIDs both with and without
 * "{}" brackets. Throws on errors.
 * @param guid
 * @param strUUID
 * @param pElm
 */
void ConfigFileBase::parseUUID(Guid &guid,
                               const Utf8Str &strUUID,
                               const xml::ElementNode *pElm) const
{
    guid = strUUID.c_str();
    if (guid.isZero())
        throw ConfigFileError(this, pElm, N_("UUID \"%s\" has zero format"), strUUID.c_str());
    else if (!guid.isValid())
        throw ConfigFileError(this, pElm, N_("UUID \"%s\" has invalid format"), strUUID.c_str());
}

/**
 * Parses the given string in str and attempts to treat it as an ISO
 * date/time stamp to put into timestamp. Throws on errors.
 * @param timestamp
 * @param str
 * @param pElm
 */
void ConfigFileBase::parseTimestamp(RTTIMESPEC &timestamp,
                                    const com::Utf8Str &str,
                                    const xml::ElementNode *pElm) const
{
    const char *pcsz = str.c_str();
        //  yyyy-mm-ddThh:mm:ss
        // "2009-07-10T11:54:03Z"
        //  01234567890123456789
        //            1
    if (str.length() > 19)
    {
        // timezone must either be unspecified or 'Z' for UTC
        if (    (pcsz[19])
             && (pcsz[19] != 'Z')
           )
            throw ConfigFileError(this, pElm, N_("Cannot handle ISO timestamp '%s': is not UTC date"), str.c_str());

        int32_t yyyy;
        uint32_t mm, dd, hh, min, secs;
        if (    (pcsz[4] == '-')
             && (pcsz[7] == '-')
             && (pcsz[10] == 'T')
             && (pcsz[13] == ':')
             && (pcsz[16] == ':')
           )
        {
            int rc;
            if (    (RT_SUCCESS(rc = RTStrToInt32Ex(pcsz, NULL, 0, &yyyy)))
                        // could theoretically be negative but let's assume that nobody
                        // created virtual machines before the Christian era
                 && (RT_SUCCESS(rc = RTStrToUInt32Ex(pcsz + 5, NULL, 0, &mm)))
                 && (RT_SUCCESS(rc = RTStrToUInt32Ex(pcsz + 8, NULL, 0, &dd)))
                 && (RT_SUCCESS(rc = RTStrToUInt32Ex(pcsz + 11, NULL, 0, &hh)))
                 && (RT_SUCCESS(rc = RTStrToUInt32Ex(pcsz + 14, NULL, 0, &min)))
                 && (RT_SUCCESS(rc = RTStrToUInt32Ex(pcsz + 17, NULL, 0, &secs)))
               )
            {
                RTTIME time =
                {
                    yyyy,
                    (uint8_t)mm,
                    0,
                    0,
                    (uint8_t)dd,
                    (uint8_t)hh,
                    (uint8_t)min,
                    (uint8_t)secs,
                    0,
                    RTTIME_FLAGS_TYPE_UTC,
                    0
                };
                if (RTTimeNormalize(&time))
                    if (RTTimeImplode(&timestamp, &time))
                        return;
            }

            throw ConfigFileError(this, pElm, N_("Cannot parse ISO timestamp '%s': runtime error, %Rra"), str.c_str(), rc);
        }

        throw ConfigFileError(this, pElm, N_("Cannot parse ISO timestamp '%s': invalid format"), str.c_str());
    }
}

/**
 * Helper function that parses a Base64 formatted string into a binary blob.
 * @param binary
 * @param str
 * @param pElm
 */
void ConfigFileBase::parseBase64(IconBlob &binary,
                                 const Utf8Str &str,
                                 const xml::ElementNode *pElm) const
{
#define DECODE_STR_MAX _1M
    const char* psz = str.c_str();
    ssize_t cbOut = RTBase64DecodedSize(psz, NULL);
    if (cbOut > DECODE_STR_MAX)
        throw ConfigFileError(this, pElm, N_("Base64 encoded data too long (%d > %d)"), cbOut, DECODE_STR_MAX);
    else if (cbOut < 0)
        throw ConfigFileError(this, pElm, N_("Base64 encoded data '%s' invalid"), psz);
    binary.resize((size_t)cbOut);
    int vrc = VINF_SUCCESS;
    if (cbOut)
        vrc = RTBase64Decode(psz, &binary.front(), (size_t)cbOut, NULL, NULL);
    if (RT_FAILURE(vrc))
    {
        binary.resize(0);
        throw ConfigFileError(this, pElm, N_("Base64 encoded data could not be decoded (%Rrc)"), vrc);
    }
}

/**
 * Helper to create a string for a RTTIMESPEC for writing out ISO timestamps.
 * @param stamp
 * @return
 */
com::Utf8Str ConfigFileBase::stringifyTimestamp(const RTTIMESPEC &stamp) const
{
    RTTIME time;
    if (!RTTimeExplode(&time, &stamp))
        throw ConfigFileError(this, NULL, N_("Timespec %lld ms is invalid"), RTTimeSpecGetMilli(&stamp));

    return Utf8StrFmt("%04u-%02u-%02uT%02u:%02u:%02uZ",
                      time.i32Year, time.u8Month, time.u8MonthDay,
                      time.u8Hour, time.u8Minute, time.u8Second);
}

/**
 * Helper to create a base64 encoded string out of a binary blob.
 * @param str
 * @param binary
 * @throws std::bad_alloc and ConfigFileError
 */
void ConfigFileBase::toBase64(com::Utf8Str &str, const IconBlob &binary) const
{
    size_t cb = binary.size();
    if (cb > 0)
    {
        size_t cchOut = RTBase64EncodedLength(cb);
        str.reserve(cchOut + 1);
        int vrc = RTBase64Encode(&binary.front(), cb, str.mutableRaw(), str.capacity(), NULL);
        if (RT_FAILURE(vrc))
            throw ConfigFileError(this, NULL, N_("Failed to convert binary data to base64 format (%Rrc)"), vrc);
        str.jolt();
    }
}

/**
 * Helper method to read in an ExtraData subtree and stores its contents
 * in the given map of extradata items. Used for both main and machine
 * extradata (MainConfigFile and MachineConfigFile).
 * @param elmExtraData
 * @param map
 */
void ConfigFileBase::readExtraData(const xml::ElementNode &elmExtraData,
                                   StringsMap &map)
{
    xml::NodesLoop nlLevel4(elmExtraData);
    const xml::ElementNode *pelmExtraDataItem;
    while ((pelmExtraDataItem = nlLevel4.forAllNodes()))
    {
        if (pelmExtraDataItem->nameEquals("ExtraDataItem"))
        {
            // <ExtraDataItem name="GUI/LastWindowPostion" value="97,88,981,858"/>
            Utf8Str strName, strValue;
            if (   pelmExtraDataItem->getAttributeValue("name", strName)
                && pelmExtraDataItem->getAttributeValue("value", strValue) )
                map[strName] = strValue;
            else
                throw ConfigFileError(this, pelmExtraDataItem, N_("Required ExtraDataItem/@name or @value attribute is missing"));
        }
    }
}

/**
 * Reads \<USBDeviceFilter\> entries from under the given elmDeviceFilters node and
 * stores them in the given linklist. This is in ConfigFileBase because it's used
 * from both MainConfigFile (for host filters) and MachineConfigFile (for machine
 * filters).
 * @param elmDeviceFilters
 * @param ll
 */
void ConfigFileBase::readUSBDeviceFilters(const xml::ElementNode &elmDeviceFilters,
                                          USBDeviceFiltersList &ll)
{
    xml::NodesLoop nl1(elmDeviceFilters, "DeviceFilter");
    const xml::ElementNode *pelmLevel4Child;
    while ((pelmLevel4Child = nl1.forAllNodes()))
    {
        USBDeviceFilter flt;
        flt.action = USBDeviceFilterAction_Ignore;
        Utf8Str strAction;
        if (   pelmLevel4Child->getAttributeValue("name", flt.strName)
            && pelmLevel4Child->getAttributeValue("active", flt.fActive))
        {
            if (!pelmLevel4Child->getAttributeValue("vendorId", flt.strVendorId))
                pelmLevel4Child->getAttributeValue("vendorid", flt.strVendorId);            // used before 1.3
            if (!pelmLevel4Child->getAttributeValue("productId", flt.strProductId))
                pelmLevel4Child->getAttributeValue("productid", flt.strProductId);          // used before 1.3
            pelmLevel4Child->getAttributeValue("revision", flt.strRevision);
            pelmLevel4Child->getAttributeValue("manufacturer", flt.strManufacturer);
            pelmLevel4Child->getAttributeValue("product", flt.strProduct);
            if (!pelmLevel4Child->getAttributeValue("serialNumber", flt.strSerialNumber))
                pelmLevel4Child->getAttributeValue("serialnumber", flt.strSerialNumber);    // used before 1.3
            pelmLevel4Child->getAttributeValue("port", flt.strPort);

            // the next 2 are irrelevant for host USB objects
            pelmLevel4Child->getAttributeValue("remote", flt.strRemote);
            pelmLevel4Child->getAttributeValue("maskedInterfaces", flt.ulMaskedInterfaces);

            // action is only used with host USB objects
            if (pelmLevel4Child->getAttributeValue("action", strAction))
            {
                if (strAction == "Ignore")
                    flt.action = USBDeviceFilterAction_Ignore;
                else if (strAction == "Hold")
                    flt.action = USBDeviceFilterAction_Hold;
                else
                    throw ConfigFileError(this, pelmLevel4Child, N_("Invalid value '%s' in DeviceFilter/@action attribute"), strAction.c_str());
            }

            ll.push_back(flt);
        }
    }
}

/**
 * Reads a media registry entry from the main VirtualBox.xml file.
 *
 * Whereas the current media registry code is fairly straightforward, it was quite a mess
 * with settings format before 1.4 (VirtualBox 2.0 used settings format 1.3). The elements
 * in the media registry were much more inconsistent, and different elements were used
 * depending on the type of device and image.
 *
 * @param t
 * @param elmMedium
 * @param med
 */
void ConfigFileBase::readMediumOne(MediaType t,
                                   const xml::ElementNode &elmMedium,
                                   Medium &med)
{
    // <HardDisk uuid="{5471ecdb-1ddb-4012-a801-6d98e226868b}" location="/mnt/innotek-unix/vdis/Windows XP.vdi" format="VDI" type="Normal">

    Utf8Str strUUID;
    if (!elmMedium.getAttributeValue("uuid", strUUID))
        throw ConfigFileError(this, &elmMedium, N_("Required %s/@uuid attribute is missing"), elmMedium.getName());

    parseUUID(med.uuid, strUUID, &elmMedium);

    bool fNeedsLocation = true;

    if (t == HardDisk)
    {
        if (m->sv < SettingsVersion_v1_4)
        {
            // here the system is:
            //         <HardDisk uuid="{....}" type="normal">
            //           <VirtualDiskImage filePath="/path/to/xxx.vdi"/>
            //         </HardDisk>

            fNeedsLocation = false;
            bool fNeedsFilePath = true;
            const xml::ElementNode *pelmImage;
            if ((pelmImage = elmMedium.findChildElement("VirtualDiskImage")))
                med.strFormat = "VDI";
            else if ((pelmImage = elmMedium.findChildElement("VMDKImage")))
                med.strFormat = "VMDK";
            else if ((pelmImage = elmMedium.findChildElement("VHDImage")))
                med.strFormat = "VHD";
            else if ((pelmImage = elmMedium.findChildElement("ISCSIHardDisk")))
            {
                med.strFormat = "iSCSI";

                fNeedsFilePath = false;
                // location is special here: current settings specify an "iscsi://user@server:port/target/lun"
                // string for the location and also have several disk properties for these, whereas this used
                // to be hidden in several sub-elements before 1.4, so compose a location string and set up
                // the properties:
                med.strLocation = "iscsi://";
                Utf8Str strUser, strServer, strPort, strTarget, strLun;
                if (pelmImage->getAttributeValue("userName", strUser))
                {
                    med.strLocation.append(strUser);
                    med.strLocation.append("@");
                }
                Utf8Str strServerAndPort;
                if (pelmImage->getAttributeValue("server", strServer))
                {
                    strServerAndPort = strServer;
                }
                if (pelmImage->getAttributeValue("port", strPort))
                {
                    if (strServerAndPort.length())
                        strServerAndPort.append(":");
                    strServerAndPort.append(strPort);
                }
                med.strLocation.append(strServerAndPort);
                if (pelmImage->getAttributeValue("target", strTarget))
                {
                    med.strLocation.append("/");
                    med.strLocation.append(strTarget);
                }
                if (pelmImage->getAttributeValue("lun", strLun))
                {
                    med.strLocation.append("/");
                    med.strLocation.append(strLun);
                }

                if (strServer.length() && strPort.length())
                    med.properties["TargetAddress"] = strServerAndPort;
                if (strTarget.length())
                    med.properties["TargetName"] = strTarget;
                if (strUser.length())
                    med.properties["InitiatorUsername"] = strUser;
                Utf8Str strPassword;
                if (pelmImage->getAttributeValue("password", strPassword))
                    med.properties["InitiatorSecret"] = strPassword;
                if (strLun.length())
                    med.properties["LUN"] = strLun;
            }
            else if ((pelmImage = elmMedium.findChildElement("CustomHardDisk")))
            {
                fNeedsFilePath = false;
                fNeedsLocation = true;
                    // also requires @format attribute, which will be queried below
            }
            else
                throw ConfigFileError(this, &elmMedium, N_("Required %s/VirtualDiskImage element is missing"), elmMedium.getName());

            if (fNeedsFilePath)
            {
                if (!(pelmImage->getAttributeValuePath("filePath", med.strLocation)))
                    throw ConfigFileError(this, &elmMedium, N_("Required %s/@filePath attribute is missing"), elmMedium.getName());
            }
        }

        if (med.strFormat.isEmpty())        // not set with 1.4 format above, or 1.4 Custom format?
            if (!elmMedium.getAttributeValue("format", med.strFormat))
                throw ConfigFileError(this, &elmMedium, N_("Required %s/@format attribute is missing"), elmMedium.getName());

        if (!elmMedium.getAttributeValue("autoReset", med.fAutoReset))
            med.fAutoReset = false;

        Utf8Str strType;
        if (elmMedium.getAttributeValue("type", strType))
        {
            // pre-1.4 used lower case, so make this case-insensitive
            strType.toUpper();
            if (strType == "NORMAL")
                med.hdType = MediumType_Normal;
            else if (strType == "IMMUTABLE")
                med.hdType = MediumType_Immutable;
            else if (strType == "WRITETHROUGH")
                med.hdType = MediumType_Writethrough;
            else if (strType == "SHAREABLE")
                med.hdType = MediumType_Shareable;
            else if (strType == "READONLY")
                med.hdType = MediumType_Readonly;
            else if (strType == "MULTIATTACH")
                med.hdType = MediumType_MultiAttach;
            else
                throw ConfigFileError(this, &elmMedium, N_("HardDisk/@type attribute must be one of Normal, Immutable, Writethrough, Shareable, Readonly or MultiAttach"));
        }
    }
    else
    {
        if (m->sv < SettingsVersion_v1_4)
        {
            // DVD and floppy images before 1.4 had "src" attribute instead of "location"
            if (!elmMedium.getAttributeValue("src", med.strLocation))
                throw ConfigFileError(this, &elmMedium, N_("Required %s/@src attribute is missing"), elmMedium.getName());

            fNeedsLocation = false;
        }

        if (!elmMedium.getAttributeValue("format", med.strFormat))
        {
            // DVD and floppy images before 1.11 had no format attribute. assign the default.
            med.strFormat = "RAW";
        }

        if (t == DVDImage)
            med.hdType = MediumType_Readonly;
        else if (t == FloppyImage)
            med.hdType = MediumType_Writethrough;
    }

    if (fNeedsLocation)
        // current files and 1.4 CustomHardDisk elements must have a location attribute
        if (!elmMedium.getAttributeValue("location", med.strLocation))
            throw ConfigFileError(this, &elmMedium, N_("Required %s/@location attribute is missing"), elmMedium.getName());

    // 3.2 builds added Description as an attribute, read it silently
    // and write it back as an element starting with 5.1.26
    elmMedium.getAttributeValue("Description", med.strDescription);

    xml::NodesLoop nlMediumChildren(elmMedium);
    const xml::ElementNode *pelmMediumChild;
    while ((pelmMediumChild = nlMediumChildren.forAllNodes()))
    {
        if (pelmMediumChild->nameEquals("Description"))
            med.strDescription = pelmMediumChild->getValue();
        else if (pelmMediumChild->nameEquals("Property"))
        {
            // handle medium properties
            Utf8Str strPropName, strPropValue;
            if (   pelmMediumChild->getAttributeValue("name", strPropName)
                && pelmMediumChild->getAttributeValue("value", strPropValue) )
                med.properties[strPropName] = strPropValue;
            else
                throw ConfigFileError(this, pelmMediumChild, N_("Required HardDisk/Property/@name or @value attribute is missing"));
        }
    }
}

/**
 * Reads a media registry entry from the main VirtualBox.xml file and
 * likewise for all children where applicable.
 *
 * @param t
 * @param elmMedium
 * @param med
 */
void ConfigFileBase::readMedium(MediaType t,
                                const xml::ElementNode &elmMedium,
                                Medium &med)
{
    std::list<const xml::ElementNode *> llElementsTodo;
    llElementsTodo.push_back(&elmMedium);
    std::list<Medium *> llSettingsTodo;
    llSettingsTodo.push_back(&med);
    std::list<uint32_t> llDepthsTodo;
    llDepthsTodo.push_back(1);

    while (llElementsTodo.size() > 0)
    {
        const xml::ElementNode *pElement = llElementsTodo.front();
        llElementsTodo.pop_front();
        Medium *pMed = llSettingsTodo.front();
        llSettingsTodo.pop_front();
        uint32_t depth = llDepthsTodo.front();
        llDepthsTodo.pop_front();

        if (depth > SETTINGS_MEDIUM_DEPTH_MAX)
            throw ConfigFileError(this, pElement, N_("Maximum medium tree depth of %u exceeded"), SETTINGS_MEDIUM_DEPTH_MAX);

        readMediumOne(t, *pElement, *pMed);

        if (t != HardDisk)
            return;

        // load all children
        xml::NodesLoop nl2(*pElement, m->sv >= SettingsVersion_v1_4 ? "HardDisk" : "DiffHardDisk");
        const xml::ElementNode *pelmHDChild;
        while ((pelmHDChild = nl2.forAllNodes()))
        {
            llElementsTodo.push_back(pelmHDChild);
            pMed->llChildren.push_back(Medium::Empty);
            llSettingsTodo.push_back(&pMed->llChildren.back());
            llDepthsTodo.push_back(depth + 1);
        }
    }
}

/**
 * Reads in the entire \<MediaRegistry\> chunk and stores its media in the lists
 * of the given MediaRegistry structure.
 *
 * This is used in both MainConfigFile and MachineConfigFile since starting with
 * VirtualBox 4.0, we can have media registries in both.
 *
 * For pre-1.4 files, this gets called with the \<DiskRegistry\> chunk instead.
 *
 * @param   elmMediaRegistry
 * @param   mr
 */
void ConfigFileBase::readMediaRegistry(const xml::ElementNode &elmMediaRegistry,
                                       MediaRegistry &mr)
{
    xml::NodesLoop nl1(elmMediaRegistry);
    const xml::ElementNode *pelmChild1;
    while ((pelmChild1 = nl1.forAllNodes()))
    {
        MediaType t = Error;
        if (pelmChild1->nameEquals("HardDisks"))
            t = HardDisk;
        else if (pelmChild1->nameEquals("DVDImages"))
            t = DVDImage;
        else if (pelmChild1->nameEquals("FloppyImages"))
            t = FloppyImage;
        else
            continue;

        xml::NodesLoop nl2(*pelmChild1);
        const xml::ElementNode *pelmMedium;
        while ((pelmMedium = nl2.forAllNodes()))
        {
            if (   t == HardDisk
                && (pelmMedium->nameEquals("HardDisk")))
            {
                mr.llHardDisks.push_back(Medium::Empty);
                readMedium(t, *pelmMedium, mr.llHardDisks.back());
            }
            else if (   t == DVDImage
                     && (pelmMedium->nameEquals("Image")))
            {
                mr.llDvdImages.push_back(Medium::Empty);
                readMedium(t, *pelmMedium, mr.llDvdImages.back());
            }
            else if (   t == FloppyImage
                     && (pelmMedium->nameEquals("Image")))
            {
                mr.llFloppyImages.push_back(Medium::Empty);
                readMedium(t, *pelmMedium, mr.llFloppyImages.back());
            }
        }
    }
}

/**
 * This is common version for reading NAT port forward rule in per-_machine's_adapter_ and
 * per-network approaches.
 * Note: this function doesn't in fill given list from xml::ElementNodesList, because there is conflicting
 * declaration in ovmfreader.h.
 */
void ConfigFileBase::readNATForwardRulesMap(const xml::ElementNode &elmParent, NATRulesMap &mapRules)
{
    xml::ElementNodesList plstRules;
    elmParent.getChildElements(plstRules, "Forwarding");
    for (xml::ElementNodesList::iterator pf = plstRules.begin(); pf != plstRules.end(); ++pf)
    {
        NATRule rule;
        uint32_t port = 0;
        (*pf)->getAttributeValue("name", rule.strName);
        (*pf)->getAttributeValue("proto", (uint32_t&)rule.proto);
        (*pf)->getAttributeValue("hostip", rule.strHostIP);
        (*pf)->getAttributeValue("hostport", port);
        rule.u16HostPort = (uint16_t)port;
        (*pf)->getAttributeValue("guestip", rule.strGuestIP);
        (*pf)->getAttributeValue("guestport", port);
        rule.u16GuestPort = (uint16_t)port;
        mapRules.insert(std::make_pair(rule.strName, rule));
    }
}

void ConfigFileBase::readNATLoopbacks(const xml::ElementNode &elmParent, NATLoopbackOffsetList &llLoopbacks)
{
    xml::ElementNodesList plstLoopbacks;
    elmParent.getChildElements(plstLoopbacks, "Loopback4");
    for (xml::ElementNodesList::iterator lo = plstLoopbacks.begin();
         lo != plstLoopbacks.end(); ++lo)
    {
        NATHostLoopbackOffset loopback;
        (*lo)->getAttributeValue("address", loopback.strLoopbackHostAddress);
        (*lo)->getAttributeValue("offset", (uint32_t&)loopback.u32Offset);
        llLoopbacks.push_back(loopback);
    }
}


/**
 * Adds a "version" attribute to the given XML element with the
 * VirtualBox settings version (e.g. "1.10-linux"). Used by
 * the XML format for the root element and by the OVF export
 * for the vbox:Machine element.
 * @param elm
 */
void ConfigFileBase::setVersionAttribute(xml::ElementNode &elm)
{
    const char *pcszVersion = NULL;
    switch (m->sv)
    {
        case SettingsVersion_v1_8:
            pcszVersion = "1.8";
            break;

        case SettingsVersion_v1_9:
            pcszVersion = "1.9";
            break;

        case SettingsVersion_v1_10:
            pcszVersion = "1.10";
            break;

        case SettingsVersion_v1_11:
            pcszVersion = "1.11";
            break;

        case SettingsVersion_v1_12:
            pcszVersion = "1.12";
            break;

        case SettingsVersion_v1_13:
            pcszVersion = "1.13";
            break;

        case SettingsVersion_v1_14:
            pcszVersion = "1.14";
            break;

        case SettingsVersion_v1_15:
            pcszVersion = "1.15";
            break;

        case SettingsVersion_v1_16:
            pcszVersion = "1.16";
            break;

        case SettingsVersion_v1_17:
            pcszVersion = "1.17";
            break;

        case SettingsVersion_v1_18:
            pcszVersion = "1.18";
            break;

        case SettingsVersion_v1_19:
            pcszVersion = "1.19";
            break;

        default:
            // catch human error: the assertion below will trigger in debug
            // or dbgopt builds, so hopefully this will get noticed sooner in
            // the future, because it's easy to forget top update something.
            AssertMsg(m->sv <= SettingsVersion_v1_7, ("Settings.cpp: unexpected settings version %d, unhandled future version?\n", m->sv));
            // silently upgrade if this is less than 1.7 because that's the oldest we can write
            if (m->sv <= SettingsVersion_v1_7)
            {
                pcszVersion = "1.7";
                m->sv = SettingsVersion_v1_7;
            }
            else
            {
                // This is reached for SettingsVersion_Future and forgotten
                // settings version after SettingsVersion_v1_7, which should
                // not happen (see assertion above). Set the version to the
                // latest known version, to minimize loss of information, but
                // as we can't predict the future we have to use some format
                // we know, and latest should be the best choice. Note that
                // for "forgotten settings" this may not be the best choice,
                // but as it's an omission of someone who changed this file
                // it's the only generic possibility.
                pcszVersion = "1.19";
                m->sv = SettingsVersion_v1_19;
            }
            break;
    }

    m->strSettingsVersionFull = Utf8StrFmt("%s-%s",
                                           pcszVersion,
                                           VBOX_XML_PLATFORM);  // e.g. "linux"
    elm.setAttribute("version", m->strSettingsVersionFull);
}


/**
 * Creates a special backup file in case there is a version
 * bump, so that it is possible to go back to the previous
 * state. This is done only once (not for every settings
 * version bump), when the settings version is newer than
 * the version read from the config file. Must be called
 * before ConfigFileBase::createStubDocument, because that
 * method may alter information which this method needs.
 */
void ConfigFileBase::specialBackupIfFirstBump()
{
    // Since this gets called before the XML document is actually written out,
    // this is where we must check whether we're upgrading the settings version
    // and need to make a backup, so the user can go back to an earlier
    // VirtualBox version and recover his old settings files.
    if (    (m->svRead != SettingsVersion_Null)     // old file exists?
         && (m->svRead < m->sv)                     // we're upgrading?
       )
    {
        // compose new filename: strip off trailing ".xml"/".vbox"
        Utf8Str strFilenameNew;
        Utf8Str strExt = ".xml";
        if (m->strFilename.endsWith(".xml"))
            strFilenameNew = m->strFilename.substr(0, m->strFilename.length() - 4);
        else if (m->strFilename.endsWith(".vbox"))
        {
            strFilenameNew = m->strFilename.substr(0, m->strFilename.length() - 5);
            strExt = ".vbox";
        }

        // and append something like "-1.3-linux.xml"
        strFilenameNew.append("-");
        strFilenameNew.append(m->strSettingsVersionFull);       // e.g. "1.3-linux"
        strFilenameNew.append(strExt);                          // .xml for main config, .vbox for machine config

        // Copying the file cannot be avoided, as doing tricks with renaming
        // causes trouble on OS X with aliases (which follow the rename), and
        // on all platforms there is a risk of "losing" the VM config when
        // running out of space, as a rename here couldn't be rolled back.
        // Ignoring all errors besides running out of space is intentional, as
        // we don't want to do anything if the file already exists.
        int vrc = RTFileCopy(m->strFilename.c_str(), strFilenameNew.c_str());
        if (RT_UNLIKELY(vrc == VERR_DISK_FULL))
            throw ConfigFileError(this, NULL, N_("Cannot create settings backup file when upgrading to a newer settings format"));

        // do this only once
        m->svRead = SettingsVersion_Null;
    }
}

/**
 * Creates a new stub xml::Document in the m->pDoc member with the
 * root "VirtualBox" element set up. This is used by both
 * MainConfigFile and MachineConfigFile at the beginning of writing
 * out their XML.
 *
 * Before calling this, it is the responsibility of the caller to
 * set the "sv" member to the required settings version that is to
 * be written. For newly created files, the settings version will be
 * recent (1.12 or later if necessary); for files read in from disk
 * earlier, it will be the settings version indicated in the file.
 * However, this method will silently make sure that the settings
 * version is always at least 1.7 and change it if necessary, since
 * there is no write support for earlier settings versions.
 */
void ConfigFileBase::createStubDocument()
{
    Assert(m->pDoc == NULL);
    m->pDoc = new xml::Document;

    m->pelmRoot = m->pDoc->createRootElement("VirtualBox",
                                             "\n"
                                             "** DO NOT EDIT THIS FILE.\n"
                                             "** If you make changes to this file while any VirtualBox related application\n"
                                             "** is running, your changes will be overwritten later, without taking effect.\n"
                                             "** Use VBoxManage or the VirtualBox Manager GUI to make changes.\n"
);
    m->pelmRoot->setAttribute("xmlns", VBOX_XML_NAMESPACE);
    // Have the code for producing a proper schema reference. Not used by most
    // tools, so don't bother doing it. The schema is not on the server anyway.
#ifdef VBOX_WITH_SETTINGS_SCHEMA
    m->pelmRoot->setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
    m->pelmRoot->setAttribute("xsi:schemaLocation", VBOX_XML_NAMESPACE " " VBOX_XML_SCHEMA);
#endif

    // add settings version attribute to root element, update m->strSettingsVersionFull
    setVersionAttribute(*m->pelmRoot);

    LogRel(("Saving settings file \"%s\" with version \"%s\"\n", m->strFilename.c_str(), m->strSettingsVersionFull.c_str()));
}

/**
 * Creates an \<ExtraData\> node under the given parent element with
 * \<ExtraDataItem\> childern according to the contents of the given
 * map.
 *
 * This is in ConfigFileBase because it's used in both MainConfigFile
 * and MachineConfigFile, which both can have extradata.
 *
 * @param elmParent
 * @param me
 */
void ConfigFileBase::buildExtraData(xml::ElementNode &elmParent,
                                    const StringsMap &me)
{
    if (me.size())
    {
        xml::ElementNode *pelmExtraData = elmParent.createChild("ExtraData");
        for (StringsMap::const_iterator it = me.begin();
             it != me.end();
             ++it)
        {
            const Utf8Str &strName = it->first;
            const Utf8Str &strValue = it->second;
            xml::ElementNode *pelmThis = pelmExtraData->createChild("ExtraDataItem");
            pelmThis->setAttribute("name", strName);
            pelmThis->setAttribute("value", strValue);
        }
    }
}

/**
 * Creates \<DeviceFilter\> nodes under the given parent element according to
 * the contents of the given USBDeviceFiltersList. This is in ConfigFileBase
 * because it's used in both MainConfigFile (for host filters) and
 * MachineConfigFile (for machine filters).
 *
 * If fHostMode is true, this means that we're supposed to write filters
 * for the IHost interface (respect "action", omit "strRemote" and
 * "ulMaskedInterfaces" in struct USBDeviceFilter).
 *
 * @param elmParent
 * @param ll
 * @param fHostMode
 */
void ConfigFileBase::buildUSBDeviceFilters(xml::ElementNode &elmParent,
                                           const USBDeviceFiltersList &ll,
                                           bool fHostMode)
{
    for (USBDeviceFiltersList::const_iterator it = ll.begin();
         it != ll.end();
         ++it)
    {
        const USBDeviceFilter &flt = *it;
        xml::ElementNode *pelmFilter = elmParent.createChild("DeviceFilter");
        pelmFilter->setAttribute("name", flt.strName);
        pelmFilter->setAttribute("active", flt.fActive);
        if (flt.strVendorId.length())
            pelmFilter->setAttribute("vendorId", flt.strVendorId);
        if (flt.strProductId.length())
            pelmFilter->setAttribute("productId", flt.strProductId);
        if (flt.strRevision.length())
            pelmFilter->setAttribute("revision", flt.strRevision);
        if (flt.strManufacturer.length())
            pelmFilter->setAttribute("manufacturer", flt.strManufacturer);
        if (flt.strProduct.length())
            pelmFilter->setAttribute("product", flt.strProduct);
        if (flt.strSerialNumber.length())
            pelmFilter->setAttribute("serialNumber", flt.strSerialNumber);
        if (flt.strPort.length())
            pelmFilter->setAttribute("port", flt.strPort);

        if (fHostMode)
        {
            const char *pcsz =
                (flt.action == USBDeviceFilterAction_Ignore) ? "Ignore"
                : /*(flt.action == USBDeviceFilterAction_Hold) ?*/ "Hold";
            pelmFilter->setAttribute("action", pcsz);
        }
        else
        {
            if (flt.strRemote.length())
                pelmFilter->setAttribute("remote", flt.strRemote);
            if (flt.ulMaskedInterfaces)
                pelmFilter->setAttribute("maskedInterfaces", flt.ulMaskedInterfaces);
        }
    }
}

/**
 * Creates a single \<HardDisk\> element for the given Medium structure
 * and all child hard disks underneath. Called from MainConfigFile::write().
 *
 * @param t
 * @param elmMedium
 * @param med
 */
void ConfigFileBase::buildMedium(MediaType t,
                                 xml::ElementNode &elmMedium,
                                 const Medium &med)
{
    std::list<const Medium *> llSettingsTodo;
    llSettingsTodo.push_back(&med);
    std::list<xml::ElementNode *> llElementsTodo;
    llElementsTodo.push_back(&elmMedium);
    std::list<uint32_t> llDepthsTodo;
    llDepthsTodo.push_back(1);

    while (llSettingsTodo.size() > 0)
    {
        const Medium *pMed = llSettingsTodo.front();
        llSettingsTodo.pop_front();
        xml::ElementNode *pElement = llElementsTodo.front();
        llElementsTodo.pop_front();
        uint32_t depth = llDepthsTodo.front();
        llDepthsTodo.pop_front();

        if (depth > SETTINGS_MEDIUM_DEPTH_MAX)
            throw ConfigFileError(this, pElement, N_("Maximum medium tree depth of %u exceeded"), SETTINGS_MEDIUM_DEPTH_MAX);

        xml::ElementNode *pelmMedium;

        if (t == HardDisk)
            pelmMedium = pElement->createChild("HardDisk");
        else
            pelmMedium = pElement->createChild("Image");

        pelmMedium->setAttribute("uuid", pMed->uuid.toStringCurly());

        pelmMedium->setAttributePath("location", pMed->strLocation);

        if (t == HardDisk || RTStrICmp(pMed->strFormat.c_str(), "RAW"))
            pelmMedium->setAttribute("format", pMed->strFormat);
        if (   t == HardDisk
            && pMed->fAutoReset)
            pelmMedium->setAttribute("autoReset", pMed->fAutoReset);
        if (pMed->strDescription.length())
            pelmMedium->createChild("Description")->addContent(pMed->strDescription);

        for (StringsMap::const_iterator it = pMed->properties.begin();
             it != pMed->properties.end();
             ++it)
        {
            xml::ElementNode *pelmProp = pelmMedium->createChild("Property");
            pelmProp->setAttribute("name", it->first);
            pelmProp->setAttribute("value", it->second);
        }

        // only for base hard disks, save the type
        if (depth == 1)
        {
            // no need to save the usual DVD/floppy medium types
            if (   (   t != DVDImage
                    || (   pMed->hdType != MediumType_Writethrough // shouldn't happen
                        && pMed->hdType != MediumType_Readonly))
                && (   t != FloppyImage
                    || pMed->hdType != MediumType_Writethrough))
            {
                const char *pcszType =
                    pMed->hdType == MediumType_Normal ? "Normal" :
                    pMed->hdType == MediumType_Immutable ? "Immutable" :
                    pMed->hdType == MediumType_Writethrough ? "Writethrough" :
                    pMed->hdType == MediumType_Shareable ? "Shareable" :
                    pMed->hdType == MediumType_Readonly ? "Readonly" :
                    pMed->hdType == MediumType_MultiAttach ? "MultiAttach" :
                    "INVALID";
                pelmMedium->setAttribute("type", pcszType);
            }
        }

        /* save all children */
        MediaList::const_iterator itBegin = pMed->llChildren.begin();
        MediaList::const_iterator itEnd = pMed->llChildren.end();
        for (MediaList::const_iterator it = itBegin; it != itEnd; ++it)
        {
            llSettingsTodo.push_back(&*it);
            llElementsTodo.push_back(pelmMedium);
            llDepthsTodo.push_back(depth + 1);
        }
    }
}

/**
 * Creates a \<MediaRegistry\> node under the given parent and writes out all
 * hard disks and DVD and floppy images from the lists in the given MediaRegistry
 * structure under it.
 *
 * This is used in both MainConfigFile and MachineConfigFile since starting with
 * VirtualBox 4.0, we can have media registries in both.
 *
 * @param elmParent
 * @param mr
 */
void ConfigFileBase::buildMediaRegistry(xml::ElementNode &elmParent,
                                        const MediaRegistry &mr)
{
    if (mr.llHardDisks.size() == 0 && mr.llDvdImages.size() == 0 && mr.llFloppyImages.size() == 0)
        return;

    xml::ElementNode *pelmMediaRegistry = elmParent.createChild("MediaRegistry");

    if (mr.llHardDisks.size())
    {
        xml::ElementNode *pelmHardDisks = pelmMediaRegistry->createChild("HardDisks");
        for (MediaList::const_iterator it = mr.llHardDisks.begin();
             it != mr.llHardDisks.end();
             ++it)
        {
            buildMedium(HardDisk, *pelmHardDisks, *it);
        }
    }

    if (mr.llDvdImages.size())
    {
        xml::ElementNode *pelmDVDImages = pelmMediaRegistry->createChild("DVDImages");
        for (MediaList::const_iterator it = mr.llDvdImages.begin();
             it != mr.llDvdImages.end();
             ++it)
        {
            buildMedium(DVDImage, *pelmDVDImages, *it);
        }
    }

    if (mr.llFloppyImages.size())
    {
        xml::ElementNode *pelmFloppyImages = pelmMediaRegistry->createChild("FloppyImages");
        for (MediaList::const_iterator it = mr.llFloppyImages.begin();
             it != mr.llFloppyImages.end();
             ++it)
        {
            buildMedium(FloppyImage, *pelmFloppyImages, *it);
        }
    }
}

/**
 * Serialize NAT port-forwarding rules in parent container.
 * Note: it's responsibility of caller to create parent of the list tag.
 * because this method used for serializing per-_mahine's_adapter_ and per-network approaches.
 */
void ConfigFileBase::buildNATForwardRulesMap(xml::ElementNode &elmParent, const NATRulesMap &mapRules)
{
    for (NATRulesMap::const_iterator r = mapRules.begin();
         r != mapRules.end(); ++r)
    {
        xml::ElementNode *pelmPF;
        pelmPF = elmParent.createChild("Forwarding");
        const NATRule &nr = r->second;
        if (nr.strName.length())
            pelmPF->setAttribute("name", nr.strName);
        pelmPF->setAttribute("proto", nr.proto);
        if (nr.strHostIP.length())
            pelmPF->setAttribute("hostip", nr.strHostIP);
        if (nr.u16HostPort)
            pelmPF->setAttribute("hostport", nr.u16HostPort);
        if (nr.strGuestIP.length())
            pelmPF->setAttribute("guestip", nr.strGuestIP);
        if (nr.u16GuestPort)
            pelmPF->setAttribute("guestport", nr.u16GuestPort);
    }
}


void ConfigFileBase::buildNATLoopbacks(xml::ElementNode &elmParent, const NATLoopbackOffsetList &natLoopbackOffsetList)
{
    for (NATLoopbackOffsetList::const_iterator lo = natLoopbackOffsetList.begin();
         lo != natLoopbackOffsetList.end(); ++lo)
    {
        xml::ElementNode *pelmLo;
        pelmLo = elmParent.createChild("Loopback4");
        pelmLo->setAttribute("address", (*lo).strLoopbackHostAddress);
        pelmLo->setAttribute("offset", (*lo).u32Offset);
    }
}

/**
 * Cleans up memory allocated by the internal XML parser. To be called by
 * descendant classes when they're done analyzing the DOM tree to discard it.
 */
void ConfigFileBase::clearDocument()
{
    m->cleanup();
}

/**
 * Returns true only if the underlying config file exists on disk;
 * either because the file has been loaded from disk, or it's been written
 * to disk, or both.
 * @return
 */
bool ConfigFileBase::fileExists()
{
    return m->fFileExists;
}

/**
 * Returns the settings file version
 *
 * @returns Settings file version enum.
 */
SettingsVersion_T ConfigFileBase::getSettingsVersion()
{
    return m->sv;
}


/**
 * Copies the base variables from another instance. Used by Machine::saveSettings
 * so that the settings version does not get lost when a copy of the Machine settings
 * file is made to see if settings have actually changed.
 * @param b
 */
void ConfigFileBase::copyBaseFrom(const ConfigFileBase &b)
{
    m->copyFrom(*b.m);
}

////////////////////////////////////////////////////////////////////////////////
//
// Structures shared between Machine XML and VirtualBox.xml
//
////////////////////////////////////////////////////////////////////////////////


/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
USBDeviceFilter::USBDeviceFilter() :
    fActive(false),
    action(USBDeviceFilterAction_Null),
    ulMaskedInterfaces(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool USBDeviceFilter::operator==(const USBDeviceFilter &u) const
{
    return (this == &u)
        || (   strName           == u.strName
            && fActive           == u.fActive
            && strVendorId       == u.strVendorId
            && strProductId      == u.strProductId
            && strRevision       == u.strRevision
            && strManufacturer   == u.strManufacturer
            && strProduct        == u.strProduct
            && strSerialNumber   == u.strSerialNumber
            && strPort           == u.strPort
            && action            == u.action
            && strRemote         == u.strRemote
            && ulMaskedInterfaces == u.ulMaskedInterfaces);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
settings::Medium::Medium() :
    fAutoReset(false),
    hdType(MediumType_Normal)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool settings::Medium::operator==(const settings::Medium &m) const
{
    return (this == &m)
        || (   uuid == m.uuid
            && strLocation == m.strLocation
            && strDescription == m.strDescription
            && strFormat == m.strFormat
            && fAutoReset == m.fAutoReset
            && properties == m.properties
            && hdType == m.hdType
            && llChildren == m.llChildren);         // this is deep and recurses
}

const struct settings::Medium settings::Medium::Empty; /* default ctor is OK */

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool MediaRegistry::operator==(const MediaRegistry &m) const
{
    return (this == &m)
        || (   llHardDisks == m.llHardDisks
            && llDvdImages == m.llDvdImages
            && llFloppyImages == m.llFloppyImages);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NATRule::NATRule() :
    proto(NATProtocol_TCP),
    u16HostPort(0),
    u16GuestPort(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool NATRule::operator==(const NATRule &r) const
{
    return (this == &r)
        || (   strName == r.strName
            && proto == r.proto
            && u16HostPort == r.u16HostPort
            && strHostIP == r.strHostIP
            && u16GuestPort == r.u16GuestPort
            && strGuestIP == r.strGuestIP);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NATHostLoopbackOffset::NATHostLoopbackOffset() :
    u32Offset(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool NATHostLoopbackOffset::operator==(const NATHostLoopbackOffset &o) const
{
    return (this == &o)
        || (   strLoopbackHostAddress == o.strLoopbackHostAddress
            && u32Offset == o.u32Offset);
}


////////////////////////////////////////////////////////////////////////////////
//
// VirtualBox.xml structures
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
SystemProperties::SystemProperties()
    : uProxyMode(ProxyMode_System)
    , uLogHistoryCount(3)
    , fExclusiveHwVirt(true)
{
#if defined(RT_OS_DARWIN) || defined(RT_OS_WINDOWS) || defined(RT_OS_SOLARIS)
    fExclusiveHwVirt = false;
#endif
}

#ifdef VBOX_WITH_UPDATE_AGENT
UpdateAgent::UpdateAgent()
   : fEnabled(false)
   , enmChannel(UpdateChannel_Stable)
   , uCheckFreqSeconds(RT_SEC_1DAY)
   , uCheckCount(0)
{
}
#endif /* VBOX_WITH_UPDATE_AGENT */

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
DhcpOptValue::DhcpOptValue()
    : strValue()
    , enmEncoding(DHCPOptionEncoding_Normal)
{
}

/**
 * Non-standard constructor.
 */
DhcpOptValue::DhcpOptValue(const com::Utf8Str &aText, DHCPOptionEncoding_T aEncoding)
    : strValue(aText)
    , enmEncoding(aEncoding)
{
}

/**
 * Default constructor.
 */
DHCPGroupCondition::DHCPGroupCondition()
    : fInclusive(true)
    , enmType(DHCPGroupConditionType_MAC)
    , strValue()
{
}

/**
 * Default constructor.
 */
DHCPConfig::DHCPConfig()
    : mapOptions()
    , secMinLeaseTime(0)
    , secDefaultLeaseTime(0)
    , secMaxLeaseTime(0)
{
}

/**
 * Default constructor.
 */
DHCPGroupConfig::DHCPGroupConfig()
    : DHCPConfig()
    , strName()
    , vecConditions()
{
}

/**
 * Default constructor.
 */
DHCPIndividualConfig::DHCPIndividualConfig()
    : DHCPConfig()
    , strMACAddress()
    , strVMName()
    , uSlot(0)
{
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
DHCPServer::DHCPServer()
    : fEnabled(false)
{
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NATNetwork::NATNetwork() :
    fEnabled(true),
    fIPv6Enabled(false),
    fAdvertiseDefaultIPv6Route(false),
    fNeedDhcpServer(true),
    u32HostLoopback6Offset(0)
{
}

#ifdef VBOX_WITH_VMNET
/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
HostOnlyNetwork::HostOnlyNetwork() :
    strNetworkMask("255.255.255.0"),
    strIPLower("192.168.56.1"),
    strIPUpper("192.168.56.199"),
    fEnabled(true)
{
    uuid.create();
}
#endif /* VBOX_WITH_VMNET */

#ifdef VBOX_WITH_CLOUD_NET
/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
CloudNetwork::CloudNetwork() :
    strProviderShortName("OCI"),
    strProfileName("Default"),
    fEnabled(true)
{
}
#endif /* VBOX_WITH_CLOUD_NET */



////////////////////////////////////////////////////////////////////////////////
//
// MainConfigFile
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Reads one \<MachineEntry\> from the main VirtualBox.xml file.
 * @param elmMachineRegistry
 */
void MainConfigFile::readMachineRegistry(const xml::ElementNode &elmMachineRegistry)
{
    // <MachineEntry uuid="{ xxx }" src="   xxx "/>
    xml::NodesLoop nl1(elmMachineRegistry);
    const xml::ElementNode *pelmChild1;
    while ((pelmChild1 = nl1.forAllNodes()))
    {
        if (pelmChild1->nameEquals("MachineEntry"))
        {
            MachineRegistryEntry mre;
            Utf8Str strUUID;
            if (   pelmChild1->getAttributeValue("uuid", strUUID)
                && pelmChild1->getAttributeValue("src", mre.strSettingsFile) )
            {
                parseUUID(mre.uuid, strUUID, pelmChild1);
                llMachines.push_back(mre);
            }
            else
                throw ConfigFileError(this, pelmChild1, N_("Required MachineEntry/@uuid or @src attribute is missing"));
        }
    }
}

/**
 * Builds the XML tree for the DHCP servers.
 */
void MainConfigFile::buildDHCPServers(xml::ElementNode &elmDHCPServers, DHCPServersList const &ll)
{
    for (DHCPServersList::const_iterator it = ll.begin(); it != ll.end(); ++it)
    {
        const DHCPServer &srv = *it;
        xml::ElementNode *pElmThis = elmDHCPServers.createChild("DHCPServer");

        pElmThis->setAttribute("networkName", srv.strNetworkName);
        pElmThis->setAttribute("IPAddress", srv.strIPAddress);
        DhcpOptConstIterator itOpt = srv.globalConfig.mapOptions.find(DHCPOption_SubnetMask);
        if (itOpt != srv.globalConfig.mapOptions.end())
            pElmThis->setAttribute("networkMask", itOpt->second.strValue);
        pElmThis->setAttribute("lowerIP", srv.strIPLower);
        pElmThis->setAttribute("upperIP", srv.strIPUpper);
        pElmThis->setAttribute("enabled", (srv.fEnabled) ? 1 : 0);        // too bad we chose 1 vs. 0 here

        /* We don't want duplicate validation check of networkMask here*/
        if (srv.globalConfig.mapOptions.size() > (itOpt != srv.globalConfig.mapOptions.end() ? 1U : 0U))
        {
            xml::ElementNode *pElmOptions = pElmThis->createChild("Options");
            buildDHCPOptions(*pElmOptions, srv.globalConfig, true);
        }

        for (DHCPGroupConfigVec::const_iterator itGroup = srv.vecGroupConfigs.begin();
             itGroup != srv.vecGroupConfigs.end(); ++itGroup)
        {
            DHCPGroupConfig const &rGroupConfig = *itGroup;

            xml::ElementNode *pElmGroup = pElmThis->createChild("Group");
            pElmGroup->setAttribute("name", rGroupConfig.strName);
            buildDHCPOptions(*pElmGroup, rGroupConfig, false);

            for (DHCPGroupConditionVec::const_iterator itCond = rGroupConfig.vecConditions.begin();
                 itCond != rGroupConfig.vecConditions.end(); ++itCond)
            {
                xml::ElementNode *pElmCondition = pElmGroup->createChild("Condition");
                pElmCondition->setAttribute("inclusive", itCond->fInclusive);
                pElmCondition->setAttribute("type", (int32_t)itCond->enmType);
                pElmCondition->setAttribute("value", itCond->strValue);
            }
        }

        for (DHCPIndividualConfigMap::const_iterator itHost = srv.mapIndividualConfigs.begin();
             itHost != srv.mapIndividualConfigs.end(); ++itHost)
        {
            DHCPIndividualConfig const &rIndividualConfig = itHost->second;

            xml::ElementNode *pElmConfig = pElmThis->createChild("Config");
            if (rIndividualConfig.strMACAddress.isNotEmpty())
                pElmConfig->setAttribute("MACAddress", rIndividualConfig.strMACAddress);
            if (rIndividualConfig.strVMName.isNotEmpty())
                pElmConfig->setAttribute("vm-name", rIndividualConfig.strVMName);
            if (rIndividualConfig.uSlot != 0 || rIndividualConfig.strVMName.isNotEmpty())
                pElmConfig->setAttribute("slot", rIndividualConfig.uSlot);
            if (rIndividualConfig.strFixedAddress.isNotEmpty())
                pElmConfig->setAttribute("fixedAddress", rIndividualConfig.strFixedAddress);
            buildDHCPOptions(*pElmConfig, rIndividualConfig, false);
        }
     }
}

/**
 * Worker for buildDHCPServers() that builds Options or Config element trees.
 */
void MainConfigFile::buildDHCPOptions(xml::ElementNode &elmOptions, DHCPConfig const &rConfig, bool fSkipSubnetMask)
{
    /* Generic (and optional) attributes on the Options or Config element: */
    if (rConfig.secMinLeaseTime > 0)
        elmOptions.setAttribute("secMinLeaseTime", rConfig.secMinLeaseTime);
    if (rConfig.secDefaultLeaseTime > 0)
        elmOptions.setAttribute("secDefaultLeaseTime", rConfig.secDefaultLeaseTime);
    if (rConfig.secMaxLeaseTime > 0)
        elmOptions.setAttribute("secMaxLeaseTime", rConfig.secMaxLeaseTime);
    if (rConfig.strForcedOptions.isNotEmpty())
        elmOptions.setAttribute("forcedOptions", rConfig.strForcedOptions);
    if (rConfig.strSuppressedOptions.isNotEmpty())
        elmOptions.setAttribute("suppressedOptions", rConfig.strSuppressedOptions);

    /* The DHCP options are <Option> child elements: */
    for (DhcpOptConstIterator it = rConfig.mapOptions.begin(); it != rConfig.mapOptions.end(); ++it)
        if (it->first != DHCPOption_SubnetMask || !fSkipSubnetMask)
        {
            xml::ElementNode *pElmOption = elmOptions.createChild("Option");
            pElmOption->setAttribute("name", it->first);
            pElmOption->setAttribute("value", it->second.strValue);
            if (it->second.enmEncoding != DHCPOptionEncoding_Normal)
                pElmOption->setAttribute("encoding", (int32_t)it->second.enmEncoding);
        }
}

/**
 * Reads in the \<DHCPServers\> chunk.
 * @param elmDHCPServers
 */
void MainConfigFile::readDHCPServers(const xml::ElementNode &elmDHCPServers)
{
    xml::NodesLoop nl1(elmDHCPServers);
    const xml::ElementNode *pelmServer;
    while ((pelmServer = nl1.forAllNodes()))
    {
        if (pelmServer->nameEquals("DHCPServer"))
        {
            DHCPServer srv;
            if (   pelmServer->getAttributeValue("networkName", srv.strNetworkName)
                && pelmServer->getAttributeValue("IPAddress", srv.strIPAddress)
                && pelmServer->getAttributeValue("networkMask", srv.globalConfig.mapOptions[DHCPOption_SubnetMask].strValue)
                && pelmServer->getAttributeValue("lowerIP", srv.strIPLower)
                && pelmServer->getAttributeValue("upperIP", srv.strIPUpper)
                && pelmServer->getAttributeValue("enabled", srv.fEnabled) )
            {
                /* Global options: */
                const xml::ElementNode *pElmOptions;
                xml::NodesLoop          nlOptions(*pelmServer, "Options");
                while ((pElmOptions = nlOptions.forAllNodes()) != NULL) /** @todo this loop makes no sense, there can only be one \<Options\> child. */
                    readDHCPOptions(srv.globalConfig, *pElmOptions, true /*fIgnoreSubnetMask*/);

                /* Group configurations: */
                xml::NodesLoop nlGroup(*pelmServer, "Group");
                const xml::ElementNode *pElmGroup;
                size_t i = 0;
                while ((pElmGroup = nlGroup.forAllNodes()) != NULL)
                {
                    srv.vecGroupConfigs.push_back(DHCPGroupConfig());
                    DHCPGroupConfig &rGroupConfig = srv.vecGroupConfigs.back();

                    if (!pElmGroup->getAttributeValue("name", rGroupConfig.strName))
                        rGroupConfig.strName.printf("Unamed Group #%u", ++i);

                    readDHCPOptions(rGroupConfig, *pElmGroup, false /*fIgnoreSubnetMask*/);

                    xml::NodesLoop nlCondition(*pElmGroup, "Condition");
                    const xml::ElementNode *pElmCondition;
                    while ((pElmCondition = nlCondition.forAllNodes()) != NULL)
                    {
                        rGroupConfig.vecConditions.push_back(DHCPGroupCondition());
                        DHCPGroupCondition &rGroupCondition = rGroupConfig.vecConditions.back();

                        if (!pElmCondition->getAttributeValue("inclusive", rGroupCondition.fInclusive))
                            rGroupCondition.fInclusive = true;

                        int32_t iType;
                        if (!pElmCondition->getAttributeValue("type", iType))
                            iType = DHCPGroupConditionType_MAC;
                        rGroupCondition.enmType = (DHCPGroupConditionType_T)iType;

                        pElmCondition->getAttributeValue("value", rGroupCondition.strValue);
                    }
                }

                /* host specific configuration: */
                xml::NodesLoop nlConfig(*pelmServer, "Config");
                const xml::ElementNode *pElmConfig;
                while ((pElmConfig = nlConfig.forAllNodes()) != NULL)
                {
                    com::Utf8Str strMACAddress;
                    if (!pElmConfig->getAttributeValue("MACAddress", strMACAddress))
                        strMACAddress.setNull();

                    com::Utf8Str strVMName;
                    if (!pElmConfig->getAttributeValue("vm-name", strVMName))
                        strVMName.setNull();

                    uint32_t uSlot;
                    if (!pElmConfig->getAttributeValue("slot", uSlot))
                        uSlot = 0;

                    com::Utf8Str strKey;
                    if (strVMName.isNotEmpty())
                        strKey.printf("%s/%u", strVMName.c_str(), uSlot);
                    else
                        strKey.printf("%s/%u", strMACAddress.c_str(), uSlot);

                    DHCPIndividualConfig &rIndividualConfig = srv.mapIndividualConfigs[strKey];
                    rIndividualConfig.strMACAddress = strMACAddress;
                    rIndividualConfig.strVMName     = strVMName;
                    rIndividualConfig.uSlot         = uSlot;
                    pElmConfig->getAttributeValue("fixedAddress", rIndividualConfig.strFixedAddress);

                    readDHCPOptions(rIndividualConfig, *pElmConfig, false /*fIgnoreSubnetMask*/);
                }

                llDhcpServers.push_back(srv);
            }
            else
                throw ConfigFileError(this, pelmServer, N_("Required DHCPServer/@networkName, @IPAddress, @networkMask, @lowerIP, @upperIP or @enabled attribute is missing"));
        }
    }
}

/**
 * Worker for readDHCPServers that reads a configuration, either global,
 * group or host (VM+NIC) specific.
 */
void MainConfigFile::readDHCPOptions(DHCPConfig &rConfig, const xml::ElementNode &elmConfig, bool fIgnoreSubnetMask)
{
    /* Generic (and optional) attributes on the Options or Config element: */
    if (!elmConfig.getAttributeValue("secMinLeaseTime", rConfig.secMinLeaseTime))
        rConfig.secMinLeaseTime = 0;
    if (!elmConfig.getAttributeValue("secDefaultLeaseTime", rConfig.secDefaultLeaseTime))
        rConfig.secDefaultLeaseTime = 0;
    if (!elmConfig.getAttributeValue("secMaxLeaseTime", rConfig.secMaxLeaseTime))
        rConfig.secMaxLeaseTime = 0;
    if (!elmConfig.getAttributeValue("forcedOptions", rConfig.strForcedOptions))
        rConfig.strSuppressedOptions.setNull();
    if (!elmConfig.getAttributeValue("suppressedOptions", rConfig.strSuppressedOptions))
        rConfig.strSuppressedOptions.setNull();

    /* The DHCP options are <Option> child elements: */
    xml::NodesLoop          nl2(elmConfig, "Option");
    const xml::ElementNode *pElmOption;
    while ((pElmOption = nl2.forAllNodes()) != NULL)
    {
        int32_t iOptName;
        if (!pElmOption->getAttributeValue("name", iOptName))
            continue;
        DHCPOption_T OptName = (DHCPOption_T)iOptName;
        if (OptName == DHCPOption_SubnetMask && fIgnoreSubnetMask)
            continue;

        com::Utf8Str strValue;
        pElmOption->getAttributeValue("value", strValue);

        int32_t iOptEnc;
        if (!pElmOption->getAttributeValue("encoding", iOptEnc))
            iOptEnc = DHCPOptionEncoding_Normal;

        rConfig.mapOptions[OptName] = DhcpOptValue(strValue, (DHCPOptionEncoding_T)iOptEnc);
    } /* end of forall("Option") */

}

/**
 * Reads in the \<NATNetworks\> chunk.
 * @param elmNATNetworks
 */
void MainConfigFile::readNATNetworks(const xml::ElementNode &elmNATNetworks)
{
    xml::NodesLoop nl1(elmNATNetworks);
    const xml::ElementNode *pelmNet;
    while ((pelmNet = nl1.forAllNodes()))
    {
        if (pelmNet->nameEquals("NATNetwork"))
        {
            NATNetwork net;
            if (   pelmNet->getAttributeValue("networkName", net.strNetworkName)
                && pelmNet->getAttributeValue("enabled", net.fEnabled)
                && pelmNet->getAttributeValue("network", net.strIPv4NetworkCidr)
                && pelmNet->getAttributeValue("ipv6", net.fIPv6Enabled)
                && pelmNet->getAttributeValue("ipv6prefix", net.strIPv6Prefix)
                && pelmNet->getAttributeValue("advertiseDefaultIPv6Route", net.fAdvertiseDefaultIPv6Route)
                && pelmNet->getAttributeValue("needDhcp", net.fNeedDhcpServer) )
            {
                pelmNet->getAttributeValue("loopback6", net.u32HostLoopback6Offset);
                const xml::ElementNode *pelmMappings;
                if ((pelmMappings = pelmNet->findChildElement("Mappings")))
                    readNATLoopbacks(*pelmMappings, net.llHostLoopbackOffsetList);

                const xml::ElementNode *pelmPortForwardRules4;
                if ((pelmPortForwardRules4 = pelmNet->findChildElement("PortForwarding4")))
                    readNATForwardRulesMap(*pelmPortForwardRules4,
                                           net.mapPortForwardRules4);

                const xml::ElementNode *pelmPortForwardRules6;
                if ((pelmPortForwardRules6 = pelmNet->findChildElement("PortForwarding6")))
                    readNATForwardRulesMap(*pelmPortForwardRules6,
                                           net.mapPortForwardRules6);

                llNATNetworks.push_back(net);
            }
            else
                throw ConfigFileError(this, pelmNet, N_("Required NATNetwork/@networkName, @gateway, @network,@advertiseDefaultIpv6Route , @needDhcp or @enabled attribute is missing"));
        }
    }
}

#ifdef VBOX_WITH_VMNET
/**
 * Reads in the \<HostOnlyNetworks\> chunk.
 * @param elmHostOnlyNetworks
 */
void MainConfigFile::readHostOnlyNetworks(const xml::ElementNode &elmHostOnlyNetworks)
{
    xml::NodesLoop nl1(elmHostOnlyNetworks);
    const xml::ElementNode *pelmNet;
    while ((pelmNet = nl1.forAllNodes()))
    {
        if (pelmNet->nameEquals("HostOnlyNetwork"))
        {
            HostOnlyNetwork net;
            Utf8Str strID;
            if (   pelmNet->getAttributeValue("name", net.strNetworkName)
                && pelmNet->getAttributeValue("mask", net.strNetworkMask)
                && pelmNet->getAttributeValue("ipLower", net.strIPLower)
                && pelmNet->getAttributeValue("ipUpper", net.strIPUpper)
                && pelmNet->getAttributeValue("id", strID)
                && pelmNet->getAttributeValue("enabled", net.fEnabled) )
            {
                parseUUID(net.uuid, strID, pelmNet);
                llHostOnlyNetworks.push_back(net);
            }
            else
                throw ConfigFileError(this, pelmNet, N_("Required HostOnlyNetwork/@name, @mask, @ipLower, @ipUpper, @id or @enabled attribute is missing"));
        }
    }
}
#endif /* VBOX_WITH_VMNET */

#ifdef VBOX_WITH_CLOUD_NET
/**
 * Reads in the \<CloudNetworks\> chunk.
 * @param elmCloudNetworks
 */
void MainConfigFile::readCloudNetworks(const xml::ElementNode &elmCloudNetworks)
{
    xml::NodesLoop nl1(elmCloudNetworks);
    const xml::ElementNode *pelmNet;
    while ((pelmNet = nl1.forAllNodes()))
    {
        if (pelmNet->nameEquals("CloudNetwork"))
        {
            CloudNetwork net;
            if (   pelmNet->getAttributeValue("name", net.strNetworkName)
                && pelmNet->getAttributeValue("provider", net.strProviderShortName)
                && pelmNet->getAttributeValue("profile", net.strProfileName)
                && pelmNet->getAttributeValue("id", net.strNetworkId)
                && pelmNet->getAttributeValue("enabled", net.fEnabled) )
            {
                llCloudNetworks.push_back(net);
            }
            else
                throw ConfigFileError(this, pelmNet, N_("Required CloudNetwork/@name, @provider, @profile, @id or @enabled attribute is missing"));
        }
    }
}
#endif /* VBOX_WITH_CLOUD_NET */

/**
 * Creates \<USBDeviceSource\> nodes under the given parent element according to
 * the contents of the given USBDeviceSourcesList.
 *
 * @param elmParent
 * @param ll
 */
void MainConfigFile::buildUSBDeviceSources(xml::ElementNode &elmParent,
                                           const USBDeviceSourcesList &ll)
{
    for (USBDeviceSourcesList::const_iterator it = ll.begin();
         it != ll.end();
         ++it)
    {
        const USBDeviceSource &src = *it;
        xml::ElementNode *pelmSource = elmParent.createChild("USBDeviceSource");
        pelmSource->setAttribute("name", src.strName);
        pelmSource->setAttribute("backend", src.strBackend);
        pelmSource->setAttribute("address", src.strAddress);

        /* Write the properties. */
        for (StringsMap::const_iterator itProp = src.properties.begin();
             itProp != src.properties.end();
             ++itProp)
        {
            xml::ElementNode *pelmProp = pelmSource->createChild("Property");
            pelmProp->setAttribute("name", itProp->first);
            pelmProp->setAttribute("value", itProp->second);
        }
    }
}

/**
 * Reads \<USBDeviceFilter\> entries from under the given elmDeviceFilters node and
 * stores them in the given linklist. This is in ConfigFileBase because it's used
 * from both MainConfigFile (for host filters) and MachineConfigFile (for machine
 * filters).
 * @param elmDeviceSources
 * @param ll
 */
void MainConfigFile::readUSBDeviceSources(const xml::ElementNode &elmDeviceSources,
                                          USBDeviceSourcesList &ll)
{
    xml::NodesLoop nl1(elmDeviceSources, "USBDeviceSource");
    const xml::ElementNode *pelmChild;
    while ((pelmChild = nl1.forAllNodes()))
    {
        USBDeviceSource src;

        if (   pelmChild->getAttributeValue("name", src.strName)
            && pelmChild->getAttributeValue("backend", src.strBackend)
            && pelmChild->getAttributeValue("address", src.strAddress))
        {
            // handle medium properties
            xml::NodesLoop nl2(*pelmChild, "Property");
            const xml::ElementNode *pelmSrcChild;
            while ((pelmSrcChild = nl2.forAllNodes()))
            {
                Utf8Str strPropName, strPropValue;
                if (   pelmSrcChild->getAttributeValue("name", strPropName)
                    && pelmSrcChild->getAttributeValue("value", strPropValue) )
                    src.properties[strPropName] = strPropValue;
                else
                    throw ConfigFileError(this, pelmSrcChild, N_("Required USBDeviceSource/Property/@name or @value attribute is missing"));
            }

            ll.push_back(src);
        }
    }
}

/**
 * Converts old style Proxy settings from ExtraData/UI section.
 *
 * Saves proxy settings directly to systemProperties structure.
 *
 * @returns true if conversion was successfull, false if not.
 * @param strUIProxySettings The GUI settings string to convert.
 */
bool MainConfigFile::convertGuiProxySettings(const com::Utf8Str &strUIProxySettings)
{
    /*
     * Possible variants:
     *    - "ProxyAuto,proxyserver.url,1080,authDisabled,,"
     *    - "ProxyDisabled,proxyserver.url,1080,authDisabled,,"
     *    - "ProxyEnabled,proxyserver.url,1080,authDisabled,,"
     *
     * Note! We only need to bother with the first three fields as the last
     *       three was never really used or ever actually passed to the HTTP
     *       client code.
     */
    /* First field: The proxy mode. */
    const char *psz = RTStrStripL(strUIProxySettings.c_str());
    static const struct { const char *psz; size_t cch; ProxyMode_T enmMode; } s_aModes[] =
    {
        { RT_STR_TUPLE("ProxyAuto"),     ProxyMode_System },
        { RT_STR_TUPLE("ProxyDisabled"), ProxyMode_NoProxy },
        { RT_STR_TUPLE("ProxyEnabled"),  ProxyMode_Manual },
    };
    for (size_t i = 0; i < RT_ELEMENTS(s_aModes); i++)
        if (RTStrNICmpAscii(psz, s_aModes[i].psz, s_aModes[i].cch) == 0)
        {
            systemProperties.uProxyMode = s_aModes[i].enmMode;
            psz = RTStrStripL(psz + s_aModes[i].cch);
            if (*psz == ',')
            {
                /* Second field: The proxy host, possibly fully fledged proxy URL. */
                psz = RTStrStripL(psz + 1);
                if (*psz != '\0' && *psz != ',')
                {
                    const char *pszEnd  = strchr(psz, ',');
                    size_t      cchHost = pszEnd ? (size_t)(pszEnd - psz) : strlen(psz);
                    while (cchHost > 0 && RT_C_IS_SPACE(psz[cchHost - 1]))
                        cchHost--;
                    systemProperties.strProxyUrl.assign(psz, cchHost);
                    if (systemProperties.strProxyUrl.find("://") == RTCString::npos)
                        systemProperties.strProxyUrl.replace(0, 0, "http://");

                    /* Third field: The proxy port. Defaulted to 1080 for all proxies.
                                    The new settings has type specific default ports.  */
                    uint16_t uPort = 1080;
                    if (pszEnd)
                    {
                        int rc = RTStrToUInt16Ex(RTStrStripL(pszEnd + 1), NULL, 10, &uPort);
                        if (RT_FAILURE(rc))
                            uPort = 1080;
                    }
                    RTURIPARSED Parsed;
                    int rc = RTUriParse(systemProperties.strProxyUrl.c_str(), &Parsed);
                    if (RT_SUCCESS(rc))
                    {
                        if (Parsed.uAuthorityPort == UINT32_MAX)
                            systemProperties.strProxyUrl.appendPrintf(systemProperties.strProxyUrl.endsWith(":")
                                                                      ? "%u" : ":%u", uPort);
                    }
                    else
                    {
                        LogRelFunc(("Dropping invalid proxy URL for %u: %s\n",
                                    systemProperties.uProxyMode, systemProperties.strProxyUrl.c_str()));
                        systemProperties.strProxyUrl.setNull();
                    }
                }
                /* else: don't bother with the rest if we haven't got a host. */
            }
            if (   systemProperties.strProxyUrl.isEmpty()
                && systemProperties.uProxyMode == ProxyMode_Manual)
            {
                systemProperties.uProxyMode = ProxyMode_System;
                return false;
            }
            return true;
        }
    LogRelFunc(("Unknown proxy type: %s\n", psz));
    return false;
}

/**
 * Constructor.
 *
 * If pstrFilename is != NULL, this reads the given settings file into the member
 * variables and various substructures and lists. Otherwise, the member variables
 * are initialized with default values.
 *
 * Throws variants of xml::Error for I/O, XML and logical content errors, which
 * the caller should catch; if this constructor does not throw, then the member
 * variables contain meaningful values (either from the file or defaults).
 *
 * @param pstrFilename
 */
MainConfigFile::MainConfigFile(const Utf8Str *pstrFilename)
    : ConfigFileBase(pstrFilename)
{
    if (pstrFilename)
    {
        // the ConfigFileBase constructor has loaded the XML file, so now
        // we need only analyze what is in there
        xml::NodesLoop nlRootChildren(*m->pelmRoot);
        const xml::ElementNode *pelmRootChild;
        bool fCopyProxySettingsFromExtraData = false;
        while ((pelmRootChild = nlRootChildren.forAllNodes()))
        {
            if (pelmRootChild->nameEquals("Global"))
            {
                xml::NodesLoop nlGlobalChildren(*pelmRootChild);
                const xml::ElementNode *pelmGlobalChild;
                while ((pelmGlobalChild = nlGlobalChildren.forAllNodes()))
                {
                    if (pelmGlobalChild->nameEquals("SystemProperties"))
                    {
                        pelmGlobalChild->getAttributeValue("defaultMachineFolder", systemProperties.strDefaultMachineFolder);
                        pelmGlobalChild->getAttributeValue("LoggingLevel", systemProperties.strLoggingLevel);
                        pelmGlobalChild->getAttributeValue("defaultHardDiskFormat", systemProperties.strDefaultHardDiskFormat);
                        if (!pelmGlobalChild->getAttributeValue("VRDEAuthLibrary", systemProperties.strVRDEAuthLibrary))
                            // pre-1.11 used @remoteDisplayAuthLibrary instead
                            pelmGlobalChild->getAttributeValue("remoteDisplayAuthLibrary", systemProperties.strVRDEAuthLibrary);
                        pelmGlobalChild->getAttributeValue("webServiceAuthLibrary", systemProperties.strWebServiceAuthLibrary);
                        pelmGlobalChild->getAttributeValue("defaultVRDEExtPack", systemProperties.strDefaultVRDEExtPack);
                        pelmGlobalChild->getAttributeValue("defaultCryptoExtPack", systemProperties.strDefaultCryptoExtPack);
                        pelmGlobalChild->getAttributeValue("LogHistoryCount", systemProperties.uLogHistoryCount);
                        pelmGlobalChild->getAttributeValue("autostartDatabasePath", systemProperties.strAutostartDatabasePath);
                        pelmGlobalChild->getAttributeValue("defaultFrontend", systemProperties.strDefaultFrontend);
                        pelmGlobalChild->getAttributeValue("exclusiveHwVirt", systemProperties.fExclusiveHwVirt);
                        if (!pelmGlobalChild->getAttributeValue("proxyMode", systemProperties.uProxyMode))
                            fCopyProxySettingsFromExtraData = true;
                        pelmGlobalChild->getAttributeValue("proxyUrl", systemProperties.strProxyUrl);
                        pelmGlobalChild->getAttributeValue("LanguageId", systemProperties.strLanguageId);
                    }
#ifdef VBOX_WITH_UPDATE_AGENT
                    else if (pelmGlobalChild->nameEquals("Updates"))
                    {
                        /* We keep the updates configuration as part of the host for now, as the API exposes the IHost::updateHost attribute,
                         * but use an own "Updates" branch in the XML for better structurizing stuff in the future. */
                        UpdateAgent &updateHost = host.updateHost;

                        xml::NodesLoop nlLevel4(*pelmGlobalChild);
                        const xml::ElementNode *pelmLevel4Child;
                        while ((pelmLevel4Child = nlLevel4.forAllNodes()))
                        {
                            if (pelmLevel4Child->nameEquals("Host"))
                            {
                                pelmLevel4Child->getAttributeValue("enabled", updateHost.fEnabled);
                                pelmLevel4Child->getAttributeValue("channel", (uint32_t&)updateHost.enmChannel);
                                pelmLevel4Child->getAttributeValue("checkFreqSec", updateHost.uCheckFreqSeconds);
                                pelmLevel4Child->getAttributeValue("repoUrl", updateHost.strRepoUrl);
                                pelmLevel4Child->getAttributeValue("lastCheckDate", updateHost.strLastCheckDate);
                                pelmLevel4Child->getAttributeValue("checkCount", updateHost.uCheckCount);
                            }
                            /** @todo Add update settings for ExtPack and Guest Additions here later. See @bugref{7983}. */
                        }

                        /* Global enabled switch for updates. Currently bound to host updates, as this is the only update we have so far. */
                        pelmGlobalChild->getAttributeValue("enabled", updateHost.fEnabled);
                    }
#endif
                    else if (pelmGlobalChild->nameEquals("ExtraData"))
                        readExtraData(*pelmGlobalChild, mapExtraDataItems);
                    else if (pelmGlobalChild->nameEquals("MachineRegistry"))
                        readMachineRegistry(*pelmGlobalChild);
                    else if (    (pelmGlobalChild->nameEquals("MediaRegistry"))
                              || (    (m->sv < SettingsVersion_v1_4)
                                   && (pelmGlobalChild->nameEquals("DiskRegistry"))
                                 )
                            )
                        readMediaRegistry(*pelmGlobalChild, mediaRegistry);
                    else if (pelmGlobalChild->nameEquals("NetserviceRegistry"))
                    {
                        xml::NodesLoop nlLevel4(*pelmGlobalChild);
                        const xml::ElementNode *pelmLevel4Child;
                        while ((pelmLevel4Child = nlLevel4.forAllNodes()))
                        {
                            if (pelmLevel4Child->nameEquals("DHCPServers"))
                                readDHCPServers(*pelmLevel4Child);
                            if (pelmLevel4Child->nameEquals("NATNetworks"))
                                readNATNetworks(*pelmLevel4Child);
#ifdef VBOX_WITH_VMNET
                            if (pelmLevel4Child->nameEquals("HostOnlyNetworks"))
                                readHostOnlyNetworks(*pelmLevel4Child);
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
                            if (pelmLevel4Child->nameEquals("CloudNetworks"))
                                readCloudNetworks(*pelmLevel4Child);
#endif /* VBOX_WITH_CLOUD_NET */
                        }
                    }
                    else if (pelmGlobalChild->nameEquals("USBDeviceFilters"))
                        readUSBDeviceFilters(*pelmGlobalChild, host.llUSBDeviceFilters);
                    else if (pelmGlobalChild->nameEquals("USBDeviceSources"))
                        readUSBDeviceSources(*pelmGlobalChild, host.llUSBDeviceSources);
                }
            } // end if (pelmRootChild->nameEquals("Global"))
        }

        if (fCopyProxySettingsFromExtraData)
            for (StringsMap::const_iterator it = mapExtraDataItems.begin(); it != mapExtraDataItems.end(); ++it)
                if (it->first.equals("GUI/ProxySettings"))
                {
                    convertGuiProxySettings(it->second);
                    break;
                }

        clearDocument();
    }

    // DHCP servers were introduced with settings version 1.7; if we're loading
    // from an older version OR this is a fresh install, then add one DHCP server
    // with default settings
    if (    (!llDhcpServers.size())
         && (    (!pstrFilename)                    // empty VirtualBox.xml file
              || (m->sv < SettingsVersion_v1_7)     // upgrading from before 1.7
            )
       )
    {
        DHCPServer srv;
#ifdef RT_OS_WINDOWS
        srv.strNetworkName = "HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adapter";
#else
        srv.strNetworkName = "HostInterfaceNetworking-vboxnet0";
#endif
        srv.strIPAddress = "192.168.56.100";
        srv.globalConfig.mapOptions[DHCPOption_SubnetMask] = DhcpOptValue("255.255.255.0");
        srv.strIPLower = "192.168.56.101";
        srv.strIPUpper = "192.168.56.254";
        srv.fEnabled = true;
        llDhcpServers.push_back(srv);
    }
}

void MainConfigFile::bumpSettingsVersionIfNeeded()
{
#ifdef VBOX_WITH_VMNET
    if (m->sv < SettingsVersion_v1_19)
    {
        // VirtualBox 7.0 adds support for host-only networks.
        if (!llHostOnlyNetworks.empty())
            m->sv = SettingsVersion_v1_19;
    }
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
    if (m->sv < SettingsVersion_v1_18)
    {
        // VirtualBox 6.1 adds support for cloud networks.
        if (!llCloudNetworks.empty())
            m->sv = SettingsVersion_v1_18;
    }
#endif /* VBOX_WITH_CLOUD_NET */

    if (m->sv < SettingsVersion_v1_16)
    {
        // VirtualBox 5.1 add support for additional USB device sources.
        if (!host.llUSBDeviceSources.empty())
            m->sv = SettingsVersion_v1_16;
    }

    if (m->sv < SettingsVersion_v1_14)
    {
        // VirtualBox 4.3 adds NAT networks.
        if (   !llNATNetworks.empty())
            m->sv = SettingsVersion_v1_14;
    }
}


/**
 * Called from the IVirtualBox interface to write out VirtualBox.xml. This
 * builds an XML DOM tree and writes it out to disk.
 */
void MainConfigFile::write(const com::Utf8Str strFilename)
{
    bumpSettingsVersionIfNeeded();

    m->strFilename = strFilename;
    specialBackupIfFirstBump();
    createStubDocument();

    xml::ElementNode *pelmGlobal = m->pelmRoot->createChild("Global");

    buildExtraData(*pelmGlobal, mapExtraDataItems);

    xml::ElementNode *pelmMachineRegistry = pelmGlobal->createChild("MachineRegistry");
    for (MachinesRegistry::const_iterator it = llMachines.begin();
         it != llMachines.end();
         ++it)
    {
        // <MachineEntry uuid="{5f102a55-a51b-48e3-b45a-b28d33469488}" src="/mnt/innotek-unix/vbox-machines/Windows 5.1 XP 1 (Office 2003)/Windows 5.1 XP 1 (Office 2003).xml"/>
        const MachineRegistryEntry &mre = *it;
        xml::ElementNode *pelmMachineEntry = pelmMachineRegistry->createChild("MachineEntry");
        pelmMachineEntry->setAttribute("uuid", mre.uuid.toStringCurly());
        pelmMachineEntry->setAttribute("src", mre.strSettingsFile);
    }

    buildMediaRegistry(*pelmGlobal, mediaRegistry);

    xml::ElementNode *pelmNetServiceRegistry = pelmGlobal->createChild("NetserviceRegistry"); /** @todo r=bird: wrong capitalization of NetServiceRegistry. sigh. */
    buildDHCPServers(*pelmNetServiceRegistry->createChild("DHCPServers"), llDhcpServers);

    xml::ElementNode *pelmNATNetworks;
    /* don't create entry if no NAT networks are registered. */
    if (!llNATNetworks.empty())
    {
        pelmNATNetworks = pelmNetServiceRegistry->createChild("NATNetworks");
        for (NATNetworksList::const_iterator it = llNATNetworks.begin();
             it != llNATNetworks.end();
             ++it)
        {
            const NATNetwork &n = *it;
            xml::ElementNode *pelmThis = pelmNATNetworks->createChild("NATNetwork");
            pelmThis->setAttribute("networkName", n.strNetworkName);
            pelmThis->setAttribute("network", n.strIPv4NetworkCidr);
            pelmThis->setAttribute("ipv6", n.fIPv6Enabled ? 1 : 0);
            pelmThis->setAttribute("ipv6prefix", n.strIPv6Prefix);
            pelmThis->setAttribute("advertiseDefaultIPv6Route", (n.fAdvertiseDefaultIPv6Route)? 1 : 0);
            pelmThis->setAttribute("needDhcp", (n.fNeedDhcpServer) ? 1 : 0);
            pelmThis->setAttribute("enabled", (n.fEnabled) ? 1 : 0);        // too bad we chose 1 vs. 0 here
            if (n.mapPortForwardRules4.size())
            {
                xml::ElementNode *pelmPf4 = pelmThis->createChild("PortForwarding4");
                buildNATForwardRulesMap(*pelmPf4, n.mapPortForwardRules4);
            }
            if (n.mapPortForwardRules6.size())
            {
                xml::ElementNode *pelmPf6 = pelmThis->createChild("PortForwarding6");
                buildNATForwardRulesMap(*pelmPf6, n.mapPortForwardRules6);
            }

            if (n.llHostLoopbackOffsetList.size())
            {
                xml::ElementNode *pelmMappings = pelmThis->createChild("Mappings");
                buildNATLoopbacks(*pelmMappings, n.llHostLoopbackOffsetList);

            }
        }
    }

#ifdef VBOX_WITH_VMNET
    xml::ElementNode *pelmHostOnlyNetworks;
    /* don't create entry if no HostOnly networks are registered. */
    if (!llHostOnlyNetworks.empty())
    {
        pelmHostOnlyNetworks = pelmNetServiceRegistry->createChild("HostOnlyNetworks");
        for (HostOnlyNetworksList::const_iterator it = llHostOnlyNetworks.begin();
             it != llHostOnlyNetworks.end();
             ++it)
        {
            const HostOnlyNetwork &n = *it;
            xml::ElementNode *pelmThis = pelmHostOnlyNetworks->createChild("HostOnlyNetwork");
            pelmThis->setAttribute("name", n.strNetworkName);
            pelmThis->setAttribute("mask", n.strNetworkMask);
            pelmThis->setAttribute("ipLower", n.strIPLower);
            pelmThis->setAttribute("ipUpper", n.strIPUpper);
            pelmThis->setAttribute("id", n.uuid.toStringCurly());
            pelmThis->setAttribute("enabled", (n.fEnabled) ? 1 : 0);        // too bad we chose 1 vs. 0 here
        }
    }
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
    xml::ElementNode *pelmCloudNetworks;
    /* don't create entry if no cloud networks are registered. */
    if (!llCloudNetworks.empty())
    {
        pelmCloudNetworks = pelmNetServiceRegistry->createChild("CloudNetworks");
        for (CloudNetworksList::const_iterator it = llCloudNetworks.begin();
             it != llCloudNetworks.end();
             ++it)
        {
            const CloudNetwork &n = *it;
            xml::ElementNode *pelmThis = pelmCloudNetworks->createChild("CloudNetwork");
            pelmThis->setAttribute("name", n.strNetworkName);
            pelmThis->setAttribute("provider", n.strProviderShortName);
            pelmThis->setAttribute("profile", n.strProfileName);
            pelmThis->setAttribute("id", n.strNetworkId);
            pelmThis->setAttribute("enabled", (n.fEnabled) ? 1 : 0);        // too bad we chose 1 vs. 0 here
        }
    }
#endif /* VBOX_WITH_CLOUD_NET */

#ifdef VBOX_WITH_UPDATE_AGENT
    /* We keep the updates configuration as part of the host for now, as the API exposes the IHost::updateHost attribute,
     * but use an own "Updates" branch in the XML for better structurizing stuff in the future. */
    UpdateAgent &updateHost = host.updateHost;

    xml::ElementNode *pelmUpdates = pelmGlobal->createChild("Updates");
    /* Global enabled switch for updates. Currently bound to host updates, as this is the only update we have so far. */
    pelmUpdates->setAttribute("enabled", updateHost.fEnabled);

    xml::ElementNode *pelmUpdateHost = pelmUpdates->createChild("Host");
    pelmUpdateHost->setAttribute("enabled", updateHost.fEnabled);
    pelmUpdateHost->setAttribute("channel", (int32_t)updateHost.enmChannel);
    pelmUpdateHost->setAttribute("checkFreqSec", updateHost.uCheckFreqSeconds);
    if (updateHost.strRepoUrl.length())
        pelmUpdateHost->setAttribute("repoUrl", updateHost.strRepoUrl);
    if (updateHost.strLastCheckDate.length())
        pelmUpdateHost->setAttribute("lastCheckDate", updateHost.strLastCheckDate);
    pelmUpdateHost->setAttribute("checkCount", updateHost.uCheckCount);
    /** @todo Add update settings for ExtPack and Guest Additions here later. See @bugref{7983}. */
#endif

    xml::ElementNode *pelmSysProps = pelmGlobal->createChild("SystemProperties");
    if (systemProperties.strDefaultMachineFolder.length())
        pelmSysProps->setAttribute("defaultMachineFolder", systemProperties.strDefaultMachineFolder);
    if (systemProperties.strLoggingLevel.length())
        pelmSysProps->setAttribute("LoggingLevel", systemProperties.strLoggingLevel);
    if (systemProperties.strDefaultHardDiskFormat.length())
        pelmSysProps->setAttribute("defaultHardDiskFormat", systemProperties.strDefaultHardDiskFormat);
    if (systemProperties.strVRDEAuthLibrary.length())
        pelmSysProps->setAttribute("VRDEAuthLibrary", systemProperties.strVRDEAuthLibrary);
    if (systemProperties.strWebServiceAuthLibrary.length())
        pelmSysProps->setAttribute("webServiceAuthLibrary", systemProperties.strWebServiceAuthLibrary);
    if (systemProperties.strDefaultVRDEExtPack.length())
        pelmSysProps->setAttribute("defaultVRDEExtPack", systemProperties.strDefaultVRDEExtPack);
    if (systemProperties.strDefaultCryptoExtPack.length())
        pelmSysProps->setAttribute("defaultCryptoExtPack", systemProperties.strDefaultCryptoExtPack);
    pelmSysProps->setAttribute("LogHistoryCount", systemProperties.uLogHistoryCount);
    if (systemProperties.strAutostartDatabasePath.length())
        pelmSysProps->setAttribute("autostartDatabasePath", systemProperties.strAutostartDatabasePath);
    if (systemProperties.strDefaultFrontend.length())
        pelmSysProps->setAttribute("defaultFrontend", systemProperties.strDefaultFrontend);
    if (systemProperties.strProxyUrl.length())
        pelmSysProps->setAttribute("proxyUrl", systemProperties.strProxyUrl);
    pelmSysProps->setAttribute("proxyMode", systemProperties.uProxyMode);
    pelmSysProps->setAttribute("exclusiveHwVirt", systemProperties.fExclusiveHwVirt);
    if (systemProperties.strLanguageId.isNotEmpty())
        pelmSysProps->setAttribute("LanguageId", systemProperties.strLanguageId);

    buildUSBDeviceFilters(*pelmGlobal->createChild("USBDeviceFilters"),
                          host.llUSBDeviceFilters,
                          true);               // fHostMode

    if (!host.llUSBDeviceSources.empty())
        buildUSBDeviceSources(*pelmGlobal->createChild("USBDeviceSources"),
                              host.llUSBDeviceSources);

    // now go write the XML
    xml::XmlFileWriter writer(*m->pDoc);
    writer.write(m->strFilename.c_str(), true /*fSafe*/);

    m->fFileExists = true;

    clearDocument();
    LogRel(("Finished saving settings file \"%s\"\n", m->strFilename.c_str()));
}

////////////////////////////////////////////////////////////////////////////////
//
// Machine XML structures
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
VRDESettings::VRDESettings() :
    fEnabled(true), // default for old VMs, for new ones it's false
    authType(AuthType_Null),
    ulAuthTimeout(5000),
    fAllowMultiConnection(false),
    fReuseSingleConnection(false)
{
}

/**
 * Check if all settings have default values.
 */
bool VRDESettings::areDefaultSettings(SettingsVersion_T sv) const
{
    return (sv < SettingsVersion_v1_16 ? fEnabled : !fEnabled)
        && authType == AuthType_Null
        && (ulAuthTimeout == 5000 || ulAuthTimeout == 0)
        && strAuthLibrary.isEmpty()
        && !fAllowMultiConnection
        && !fReuseSingleConnection
        && strVrdeExtPack.isEmpty()
        && mapProperties.size() == 0;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool VRDESettings::operator==(const VRDESettings& v) const
{
    return (this == &v)
        || (   fEnabled                  == v.fEnabled
            && authType                  == v.authType
            && ulAuthTimeout             == v.ulAuthTimeout
            && strAuthLibrary            == v.strAuthLibrary
            && fAllowMultiConnection     == v.fAllowMultiConnection
            && fReuseSingleConnection    == v.fReuseSingleConnection
            && strVrdeExtPack            == v.strVrdeExtPack
            && mapProperties             == v.mapProperties);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
BIOSSettings::BIOSSettings() :
    fACPIEnabled(true),
    fIOAPICEnabled(false),
    fLogoFadeIn(true),
    fLogoFadeOut(true),
    fPXEDebugEnabled(false),
    fSmbiosUuidLittleEndian(true),
    ulLogoDisplayTime(0),
    biosBootMenuMode(BIOSBootMenuMode_MessageAndMenu),
    apicMode(APICMode_APIC),
    llTimeOffset(0)
{
}

/**
 * Check if all settings have default values.
 */
bool BIOSSettings::areDefaultSettings() const
{
    return fACPIEnabled
        && !fIOAPICEnabled
        && fLogoFadeIn
        && fLogoFadeOut
        && !fPXEDebugEnabled
        && !fSmbiosUuidLittleEndian
        && ulLogoDisplayTime == 0
        && biosBootMenuMode == BIOSBootMenuMode_MessageAndMenu
        && apicMode == APICMode_APIC
        && llTimeOffset == 0
        && strLogoImagePath.isEmpty();
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool BIOSSettings::operator==(const BIOSSettings &d) const
{
    return (this == &d)
        || (   fACPIEnabled            == d.fACPIEnabled
            && fIOAPICEnabled          == d.fIOAPICEnabled
            && fLogoFadeIn             == d.fLogoFadeIn
            && fLogoFadeOut            == d.fLogoFadeOut
            && fPXEDebugEnabled        == d.fPXEDebugEnabled
            && fSmbiosUuidLittleEndian == d.fSmbiosUuidLittleEndian
            && ulLogoDisplayTime       == d.ulLogoDisplayTime
            && biosBootMenuMode        == d.biosBootMenuMode
            && apicMode                == d.apicMode
            && llTimeOffset            == d.llTimeOffset
            && strLogoImagePath        == d.strLogoImagePath);
}

RecordingScreenSettings::RecordingScreenSettings(uint32_t a_idScreen /* = UINT32_MAX */)
    : idScreen(a_idScreen)
{
    applyDefaults();
}

RecordingScreenSettings::~RecordingScreenSettings()
{

}

/**
 * Returns the default options string for screen recording settings.
 *
 * @returns Default options string for a given screen.
 */
/* static */
const char *RecordingScreenSettings::getDefaultOptions(void)
{
    /* Note: Needs to be kept in sync with FE/Qt's UIMachineSettingsDisplay::putToCache()! */
    return "vc_enabled=true,ac_enabled=false,ac_profile=med";
}

/**
 * Returns a recording settings feature map from a given string.
 *
 * @returns VBox status code.
 * @param   strFeatures         String of features to convert.
 * @param   featureMap          Where to return the converted features on success.
 */
/* static */
int RecordingScreenSettings::featuresFromString(const com::Utf8Str &strFeatures, RecordingFeatureMap &featureMap)
{
    featureMap.clear();

    RTCList<RTCString> lstFeatures = strFeatures.split(" ");
    for (size_t i = 0; i < lstFeatures.size(); i++)
    {
        if (lstFeatures.at(i).compare("video", RTCString::CaseInsensitive) == 0)
            featureMap[RecordingFeature_Video] = true;
        else if (lstFeatures.at(i).compare("audio", RTCString::CaseInsensitive) == 0)
            featureMap[RecordingFeature_Audio] = true;
        /* ignore everything else */
    }

    return VINF_SUCCESS;
}

/**
 * Converts a feature map to a serializable string.
 *
 * @param   featureMap          Feature map to convert.
 * @param   strFeatures         Where to return the features converted as a string.
 */
/* static */
void RecordingScreenSettings::featuresToString(const RecordingFeatureMap &featureMap, com::Utf8Str &strFeatures)
{
    strFeatures = "";

    RecordingFeatureMap::const_iterator itFeature = featureMap.begin();
    while (itFeature != featureMap.end())
    {
        if (itFeature->first == RecordingFeature_Video && itFeature->second)
            strFeatures += "video ";
        if (itFeature->first == RecordingFeature_Audio && itFeature->second)
            strFeatures += "audio ";
        ++itFeature;
    }
    strFeatures.strip();
}

/**
 * Returns a recording settings audio codec from a given string.
 *
 * @returns VBox status code.
 * @retval  VERR_NOT_SUPPORTED if audio codec is invalid or not supported.
 * @param   strCodec            String that contains the codec name.
 * @param   enmCodec            Where to return the audio codec on success.
 *
 * @note    An empty string will return "none" (no codec).
 */
/* static */
int RecordingScreenSettings::audioCodecFromString(const com::Utf8Str &strCodec, RecordingAudioCodec_T &enmCodec)
{
    if (   RTStrIStr(strCodec.c_str(), "none")
        || strCodec.isEmpty())
    {
        enmCodec = RecordingAudioCodec_None;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "wav"))
    {
        enmCodec = RecordingAudioCodec_WavPCM;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "mp3"))
    {
        enmCodec = RecordingAudioCodec_MP3;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "opus"))
    {
        enmCodec = RecordingAudioCodec_Opus;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "vorbis"))
    {
        enmCodec = RecordingAudioCodec_OggVorbis;
        return VINF_SUCCESS;
    }

    AssertFailedReturn(VERR_NOT_SUPPORTED);
}

/**
 * Converts an audio codec to a serializable string.
 *
 * @param   enmCodec            Codec to convert to a string.
 * @param   strCodec            Where to return the audio codec converted as a string.
 */
/* static */
void RecordingScreenSettings::audioCodecToString(const RecordingAudioCodec_T &enmCodec, com::Utf8Str &strCodec)
{
    switch (enmCodec)
    {
        case RecordingAudioCodec_None:      strCodec = "none";   return;
        case RecordingAudioCodec_WavPCM:    strCodec = "wav";    return;
        case RecordingAudioCodec_MP3:       strCodec = "mp3";    return;
        case RecordingAudioCodec_Opus:      strCodec = "opus";   return;
        case RecordingAudioCodec_OggVorbis: strCodec = "vorbis"; return;
        default:                            AssertFailedReturnVoid();
    }
}

/**
 * Returns a recording settings video codec from a given string.
 *
 * @returns VBox status code.
 * @retval  VERR_NOT_SUPPORTED if video codec is invalid or not supported.
 * @param   strCodec            String that contains the codec name.
 * @param   enmCodec            Where to return the video codec on success.
 *
 * @note    An empty string will return "none" (no codec).
 */
/* static */
int RecordingScreenSettings::videoCodecFromString(const com::Utf8Str &strCodec, RecordingVideoCodec_T &enmCodec)
{
    if (   RTStrIStr(strCodec.c_str(), "none")
        || strCodec.isEmpty())
    {
        enmCodec = RecordingVideoCodec_None;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "MJPEG"))
    {
        enmCodec = RecordingVideoCodec_MJPEG;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "H262"))
    {
        enmCodec = RecordingVideoCodec_H262;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "H264"))
    {
        enmCodec = RecordingVideoCodec_H264;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "H265"))
    {
        enmCodec = RecordingVideoCodec_H265;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "H266"))
    {
        enmCodec = RecordingVideoCodec_H266;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "VP8"))
    {
        enmCodec = RecordingVideoCodec_VP8;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "VP9"))
    {
        enmCodec = RecordingVideoCodec_VP9;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "AV1"))
    {
        enmCodec = RecordingVideoCodec_AV1;
        return VINF_SUCCESS;
    }
    else if (RTStrIStr(strCodec.c_str(), "other"))
    {
        enmCodec = RecordingVideoCodec_Other;
        return VINF_SUCCESS;
    }

    AssertFailedReturn(VERR_NOT_SUPPORTED);
}

/**
 * Converts a video codec to a serializable string.
 *
 * @param   enmCodec            Codec to convert to a string.
 * @param   strCodec            Where to return the video codec converted as a string.
 */
/* static */
void RecordingScreenSettings::videoCodecToString(const RecordingVideoCodec_T &enmCodec, com::Utf8Str &strCodec)
{
    switch (enmCodec)
    {
        case RecordingVideoCodec_None:  strCodec = "none";  return;
        case RecordingVideoCodec_MJPEG: strCodec = "MJPEG"; return;
        case RecordingVideoCodec_H262:  strCodec = "H262";  return;
        case RecordingVideoCodec_H264:  strCodec = "H264";  return;
        case RecordingVideoCodec_H265:  strCodec = "H265";  return;
        case RecordingVideoCodec_H266:  strCodec = "H266";  return;
        case RecordingVideoCodec_VP8:   strCodec = "VP8";   return;
        case RecordingVideoCodec_VP9:   strCodec = "VP9";   return;
        case RecordingVideoCodec_AV1:   strCodec = "AV1";   return;
        case RecordingVideoCodec_Other: strCodec = "other"; return;
        default:                        AssertFailedReturnVoid();
    }
}

/**
 * Applies the default settings.
 */
void RecordingScreenSettings::applyDefaults(void)
{
    /*
     * Set sensible defaults.
     */

    /*
     * Enable screen 0 by default.
     * Otherwise enabling recording without any screen enabled at all makes no sense.
     *
     * Note: When tweaking this, make sure to also alter RecordingScreenSettings::areDefaultSettings().
     */
    fEnabled             = idScreen == 0 ? true : false;;
    enmDest              = RecordingDestination_File;
    ulMaxTimeS           = 0;
    strOptions           = RecordingScreenSettings::getDefaultOptions();
    File.ulMaxSizeMB     = 0;
    File.strName         = "";
    Video.enmCodec       = RecordingVideoCodec_VP8;
    Video.enmDeadline    = RecordingCodecDeadline_Default;
    Video.enmRateCtlMode = RecordingRateControlMode_VBR;
    Video.enmScalingMode = RecordingVideoScalingMode_None;
    Video.ulWidth        = 1024;
    Video.ulHeight       = 768;
    Video.ulRate         = 512;
    Video.ulFPS          = 25;
#ifdef VBOX_WITH_AUDIO_RECORDING
# if   defined(VBOX_WITH_LIBVORBIS)
    Audio.enmCodec       = RecordingAudioCodec_OggVorbis;
# else
    Audio.enmCodec       = RecordingAudioCodec_None;
# endif
#else
    Audio.enmCodec       = RecordingAudioCodec_None;
#endif /* VBOX_WITH_RECORDING */
    Audio.enmDeadline    = RecordingCodecDeadline_Default;
    Audio.enmRateCtlMode = RecordingRateControlMode_VBR;
    Audio.cBits          = 16;
    Audio.cChannels      = 2;
    Audio.uHz            = 22050;

    featureMap[RecordingFeature_Video] = true;
    featureMap[RecordingFeature_Audio] = false; /** @todo Audio is not yet enabled by default. */
}

/**
 * Check if all settings have default values.
 *
 * @returns @c true if default, @c false if not.
 */
bool RecordingScreenSettings::areDefaultSettings(void) const
{
    return    (   fEnabled                                    == false
               /* Screen 0 is special: There we ALWAYS enable recording by default. */
               || (   idScreen                                == 0
                   && fEnabled                                == true)
              )
           && enmDest                                         == RecordingDestination_File
           && ulMaxTimeS                                      == 0
           && strOptions                                      == RecordingScreenSettings::getDefaultOptions()
           && File.ulMaxSizeMB                                == 0
           && File.strName                                    == ""
           && Video.enmCodec                                  == RecordingVideoCodec_VP8
           && Video.enmDeadline                               == RecordingCodecDeadline_Default
           && Video.enmRateCtlMode                            == RecordingRateControlMode_VBR
           && Video.enmScalingMode                            == RecordingVideoScalingMode_None
           && Video.ulWidth                                   == 1024
           && Video.ulHeight                                  == 768
           && Video.ulRate                                    == 512
           && Video.ulFPS                                     == 25
#ifdef VBOX_WITH_AUDIO_RECORDING
# if   defined(VBOX_WITH_LIBVORBIS)
           && Audio.enmCodec                                  == RecordingAudioCodec_OggVorbis
# else
           && Audio.enmCodec                                  == RecordingAudioCodec_None
# endif
#else
           && Audio.enmCodec                                  == RecordingAudioCodec_None
#endif /* VBOX_WITH_AUDIO_RECORDING */
           && Audio.enmDeadline                               == RecordingCodecDeadline_Default
           && Audio.enmRateCtlMode                            == RecordingRateControlMode_VBR
           && Audio.cBits                                     == 16
           && Audio.cChannels                                 == 2
           && Audio.uHz                                       == 22050
           && featureMap.find(RecordingFeature_Video)->second == true
           && featureMap.find(RecordingFeature_Audio)->second == false;
}

/**
 * Returns if a certain recording feature is enabled or not.
 *
 * @returns @c true if the feature is enabled, @c false if not.
 * @param   enmFeature          Feature to check.
 */
bool RecordingScreenSettings::isFeatureEnabled(RecordingFeature_T enmFeature) const
{
    RecordingFeatureMap::const_iterator itFeature = featureMap.find(enmFeature);
    if (itFeature != featureMap.end())
        return itFeature->second;

    return false;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool RecordingScreenSettings::operator==(const RecordingScreenSettings &d) const
{
    return    fEnabled             == d.fEnabled
           && enmDest              == d.enmDest
           && featureMap           == d.featureMap
           && ulMaxTimeS           == d.ulMaxTimeS
           && strOptions           == d.strOptions
           && File.strName         == d.File.strName
           && File.ulMaxSizeMB     == d.File.ulMaxSizeMB
           && Video.enmCodec       == d.Video.enmCodec
           && Video.enmDeadline    == d.Video.enmDeadline
           && Video.enmRateCtlMode == d.Video.enmRateCtlMode
           && Video.enmScalingMode == d.Video.enmScalingMode
           && Video.ulWidth        == d.Video.ulWidth
           && Video.ulHeight       == d.Video.ulHeight
           && Video.ulRate         == d.Video.ulRate
           && Video.ulFPS          == d.Video.ulFPS
           && Audio.enmCodec       == d.Audio.enmCodec
           && Audio.enmDeadline    == d.Audio.enmDeadline
           && Audio.enmRateCtlMode == d.Audio.enmRateCtlMode
           && Audio.cBits          == d.Audio.cBits
           && Audio.cChannels      == d.Audio.cChannels
           && Audio.uHz            == d.Audio.uHz
           && featureMap           == d.featureMap;
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
RecordingCommonSettings::RecordingCommonSettings()
{
    applyDefaults();
}

/**
 * Applies the default settings.
 */
void RecordingCommonSettings::applyDefaults(void)
{
    fEnabled = false;
}

/**
 * Check if all settings have default values.
 */
bool RecordingCommonSettings::areDefaultSettings(void) const
{
    return fEnabled == false;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool RecordingCommonSettings::operator==(const RecordingCommonSettings &d) const
{
    if (this == &d)
        return true;

    return fEnabled == d.fEnabled;
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
RecordingSettings::RecordingSettings()
{
    applyDefaults();
}

/**
 * Applies the default settings.
 */
void RecordingSettings::applyDefaults(void)
{
    common.applyDefaults();

    mapScreens.clear();

    try
    {
        /* Always add screen 0 to the default configuration. */
        RecordingScreenSettings screenSettings(0 /* Screen ID */);

        mapScreens[0 /* Screen ID */] = screenSettings;
    }
    catch (std::bad_alloc &)
    {
        AssertFailed();
    }
}

/**
 * Check if all settings have default values.
 */
bool RecordingSettings::areDefaultSettings(void) const
{
    AssertReturn(mapScreens.size() >= 1, false); /* The first screen always must be present. */

    if (!common.areDefaultSettings())
        return false;

    RecordingScreenSettingsMap::const_iterator itScreen = mapScreens.begin();
    while (itScreen != mapScreens.end())
    {
        if (!itScreen->second.areDefaultSettings())
            return false;
        ++itScreen;
    }

    return true;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool RecordingSettings::operator==(const RecordingSettings &that) const
{
    if (this == &that) /* If pointers match, take a shortcut. */
        return true;

    if (common == that.common)
    {
        /* Too lazy for a != operator. */
    }
    else
        return false;

    if (mapScreens.size() != that.mapScreens.size())
        return false;

    RecordingScreenSettingsMap::const_iterator itScreen     = mapScreens.begin();
    RecordingScreenSettingsMap::const_iterator itScreenThat = that.mapScreens.begin();
    while (   itScreen     != mapScreens.end()
           && itScreenThat != that.mapScreens.end())
    {
        if (itScreen->second == itScreenThat->second)
        {
            /* Nothing to do in here (yet). */
        }
        else
            return false;

        ++itScreen;
        ++itScreenThat;
    }

    return true;
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
GraphicsAdapter::GraphicsAdapter() :
    graphicsControllerType(GraphicsControllerType_VBoxVGA),
    ulVRAMSizeMB(8),
    cMonitors(1),
    fAccelerate3D(false),
    fAccelerate2DVideo(false)
{
}

/**
 * Check if all settings have default values.
 */
bool GraphicsAdapter::areDefaultSettings() const
{
    return graphicsControllerType == GraphicsControllerType_VBoxVGA
        && ulVRAMSizeMB == 8
        && cMonitors <= 1
        && !fAccelerate3D
        && !fAccelerate2DVideo;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool GraphicsAdapter::operator==(const GraphicsAdapter &g) const
{
    return (this == &g)
        || (   graphicsControllerType         == g.graphicsControllerType
            && ulVRAMSizeMB                   == g.ulVRAMSizeMB
            && cMonitors                      == g.cMonitors
            && fAccelerate3D                  == g.fAccelerate3D
            && fAccelerate2DVideo             == g.fAccelerate2DVideo);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
TpmSettings::TpmSettings() :
    tpmType(TpmType_None)
{
}

/**
 * Check if all settings have default values.
 */
bool TpmSettings::areDefaultSettings() const
{
    return    tpmType     == TpmType_None
           && strLocation.isEmpty();
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool TpmSettings::operator==(const TpmSettings &g) const
{
    return (this == &g)
        || (   tpmType         == g.tpmType
            && strLocation     == g.strLocation);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NvramSettings::NvramSettings()
{
}

/**
 * Check if all settings have default values.
 */
bool NvramSettings::areDefaultSettings() const
{
    return     strNvramPath.isEmpty()
            && strKeyId.isEmpty()
            && strKeyStore.isEmpty();
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool NvramSettings::operator==(const NvramSettings &g) const
{
    return (this == &g)
        || (strNvramPath    == g.strNvramPath)
        || (strKeyId        == g.strKeyId)
        || (strKeyStore     == g.strKeyStore);
}


/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
USBController::USBController() :
    enmType(USBControllerType_Null)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool USBController::operator==(const USBController &u) const
{
    return (this == &u)
        || (   strName == u.strName
            && enmType == u.enmType);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
USB::USB()
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool USB::operator==(const USB &u) const
{
    return (this == &u)
        || (   llUSBControllers == u.llUSBControllers
            && llDeviceFilters  == u.llDeviceFilters);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NAT::NAT() :
    u32Mtu(0),
    u32SockRcv(0),
    u32SockSnd(0),
    u32TcpRcv(0),
    u32TcpSnd(0),
    fDNSPassDomain(true), /* historically this value is true */
    fDNSProxy(false),
    fDNSUseHostResolver(false),
    fAliasLog(false),
    fAliasProxyOnly(false),
    fAliasUseSamePorts(false),
    fLocalhostReachable(true) /* Historically this value is true. */
{
}

/**
 * Check if all DNS settings have default values.
 */
bool NAT::areDNSDefaultSettings() const
{
    return fDNSPassDomain && !fDNSProxy && !fDNSUseHostResolver;
}

/**
 * Check if all Alias settings have default values.
 */
bool NAT::areAliasDefaultSettings() const
{
    return !fAliasLog && !fAliasProxyOnly && !fAliasUseSamePorts;
}

/**
 * Check if all TFTP settings have default values.
 */
bool NAT::areTFTPDefaultSettings() const
{
    return strTFTPPrefix.isEmpty()
        && strTFTPBootFile.isEmpty()
        && strTFTPNextServer.isEmpty();
}

/**
 * Check whether the localhost-reachable setting is the default for the given settings version.
 */
bool NAT::areLocalhostReachableDefaultSettings(SettingsVersion_T sv) const
{
    return    (   fLocalhostReachable
                && sv < SettingsVersion_v1_19)
           || (   !fLocalhostReachable
                && sv >= SettingsVersion_v1_19);
}

/**
 * Check if all settings have default values.
 */
bool NAT::areDefaultSettings(SettingsVersion_T sv) const
{
    /*
     * Before settings version 1.19 localhost was reachable by default
     * when using NAT which was changed with version 1.19+, see @bugref{9896}
     * for more information.
     */
    return strNetwork.isEmpty()
        && strBindIP.isEmpty()
        && u32Mtu == 0
        && u32SockRcv == 0
        && u32SockSnd == 0
        && u32TcpRcv == 0
        && u32TcpSnd == 0
        && areDNSDefaultSettings()
        && areAliasDefaultSettings()
        && areTFTPDefaultSettings()
        && mapRules.size() == 0
        && areLocalhostReachableDefaultSettings(sv);
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool NAT::operator==(const NAT &n) const
{
   return (this == &n)
       || (   strNetwork           == n.strNetwork
            && strBindIP           == n.strBindIP
            && u32Mtu              == n.u32Mtu
            && u32SockRcv          == n.u32SockRcv
            && u32SockSnd          == n.u32SockSnd
            && u32TcpSnd           == n.u32TcpSnd
            && u32TcpRcv           == n.u32TcpRcv
            && strTFTPPrefix       == n.strTFTPPrefix
            && strTFTPBootFile     == n.strTFTPBootFile
            && strTFTPNextServer   == n.strTFTPNextServer
            && fDNSPassDomain      == n.fDNSPassDomain
            && fDNSProxy           == n.fDNSProxy
            && fDNSUseHostResolver == n.fDNSUseHostResolver
            && fAliasLog           == n.fAliasLog
            && fAliasProxyOnly     == n.fAliasProxyOnly
            && fAliasUseSamePorts  == n.fAliasUseSamePorts
            && fLocalhostReachable == n.fLocalhostReachable
            && mapRules            == n.mapRules);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
NetworkAdapter::NetworkAdapter() :
    ulSlot(0),
    type(NetworkAdapterType_Am79C970A), // default for old VMs, for new ones it's Am79C973
    fEnabled(false),
    fCableConnected(false), // default for old VMs, for new ones it's true
    ulLineSpeed(0),
    enmPromiscModePolicy(NetworkAdapterPromiscModePolicy_Deny),
    fTraceEnabled(false),
    mode(NetworkAttachmentType_Null),
    ulBootPriority(0)
{
}

/**
 * Check if all Generic Driver settings have default values.
 */
bool NetworkAdapter::areGenericDriverDefaultSettings() const
{
    return strGenericDriver.isEmpty()
        && genericProperties.size() == 0;
}

/**
 * Check if all settings have default values.
 */
bool NetworkAdapter::areDefaultSettings(SettingsVersion_T sv) const
{
    // 5.0 and earlier had a default of fCableConnected=false, which doesn't
    // make a lot of sense (but it's a fact). Later versions don't save the
    // setting if it's at the default value and thus must get it right.
    return !fEnabled
        && strMACAddress.isEmpty()
        && (   (sv >= SettingsVersion_v1_16 && fCableConnected && type == NetworkAdapterType_Am79C973)
            || (sv < SettingsVersion_v1_16 && !fCableConnected && type == NetworkAdapterType_Am79C970A))
        && ulLineSpeed == 0
        && enmPromiscModePolicy == NetworkAdapterPromiscModePolicy_Deny
        && mode == NetworkAttachmentType_Null
        && nat.areDefaultSettings(sv)
        && strBridgedName.isEmpty()
        && strInternalNetworkName.isEmpty()
#ifdef VBOX_WITH_VMNET
        && strHostOnlyNetworkName.isEmpty()
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
        && strCloudNetworkName.isEmpty()
#endif /* VBOX_WITH_CLOUD_NET */
        && strHostOnlyName.isEmpty()
        && areGenericDriverDefaultSettings()
        && strNATNetworkName.isEmpty();
}

/**
 * Special check if settings of the non-current attachment type have default values.
 */
bool NetworkAdapter::areDisabledDefaultSettings(SettingsVersion_T sv) const
{
    return (mode != NetworkAttachmentType_NAT ? nat.areDefaultSettings(sv) : true)
        && (mode != NetworkAttachmentType_Bridged ? strBridgedName.isEmpty() : true)
        && (mode != NetworkAttachmentType_Internal ? strInternalNetworkName.isEmpty() : true)
#ifdef VBOX_WITH_VMNET
        && (mode != NetworkAttachmentType_HostOnlyNetwork ? strHostOnlyNetworkName.isEmpty() : true)
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
        && (mode != NetworkAttachmentType_Cloud ? strCloudNetworkName.isEmpty() : true)
#endif /* VBOX_WITH_CLOUD_NET */
        && (mode != NetworkAttachmentType_HostOnly ? strHostOnlyName.isEmpty() : true)
        && (mode != NetworkAttachmentType_Generic ? areGenericDriverDefaultSettings() : true)
        && (mode != NetworkAttachmentType_NATNetwork ? strNATNetworkName.isEmpty() : true);
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool NetworkAdapter::operator==(const NetworkAdapter &n) const
{
    return (this == &n)
        || (   ulSlot                == n.ulSlot
            && type                  == n.type
            && fEnabled              == n.fEnabled
            && strMACAddress         == n.strMACAddress
            && fCableConnected       == n.fCableConnected
            && ulLineSpeed           == n.ulLineSpeed
            && enmPromiscModePolicy  == n.enmPromiscModePolicy
            && fTraceEnabled         == n.fTraceEnabled
            && strTraceFile          == n.strTraceFile
            && mode                  == n.mode
            && nat                   == n.nat
            && strBridgedName        == n.strBridgedName
            && strHostOnlyName       == n.strHostOnlyName
#ifdef VBOX_WITH_VMNET
            && strHostOnlyNetworkName == n.strHostOnlyNetworkName
#endif /* VBOX_WITH_VMNET */
            && strInternalNetworkName == n.strInternalNetworkName
#ifdef VBOX_WITH_CLOUD_NET
            && strCloudNetworkName   == n.strCloudNetworkName
#endif /* VBOX_WITH_CLOUD_NET */
            && strGenericDriver      == n.strGenericDriver
            && genericProperties     == n.genericProperties
            && ulBootPriority        == n.ulBootPriority
            && strBandwidthGroup     == n.strBandwidthGroup);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
SerialPort::SerialPort() :
    ulSlot(0),
    fEnabled(false),
    ulIOBase(0x3f8),
    ulIRQ(4),
    portMode(PortMode_Disconnected),
    fServer(false),
    uartType(UartType_U16550A)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool SerialPort::operator==(const SerialPort &s) const
{
    return (this == &s)
        || (   ulSlot            == s.ulSlot
            && fEnabled          == s.fEnabled
            && ulIOBase          == s.ulIOBase
            && ulIRQ             == s.ulIRQ
            && portMode          == s.portMode
            && strPath           == s.strPath
            && fServer           == s.fServer
            && uartType          == s.uartType);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
ParallelPort::ParallelPort() :
    ulSlot(0),
    fEnabled(false),
    ulIOBase(0x378),
    ulIRQ(7)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool ParallelPort::operator==(const ParallelPort &s) const
{
    return (this == &s)
        || (   ulSlot            == s.ulSlot
            && fEnabled          == s.fEnabled
            && ulIOBase          == s.ulIOBase
            && ulIRQ             == s.ulIRQ
            && strPath           == s.strPath);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
AudioAdapter::AudioAdapter() :
    fEnabled(true), // default for old VMs, for new ones it's false
    fEnabledIn(true), // default for old VMs, for new ones it's false
    fEnabledOut(true), // default for old VMs, for new ones it's false
    controllerType(AudioControllerType_AC97),
    codecType(AudioCodecType_STAC9700),
    driverType(AudioDriverType_Null)
{
}

/**
 * Check if all settings have default values.
 */
bool AudioAdapter::areDefaultSettings(SettingsVersion_T sv) const
{
    return (sv < SettingsVersion_v1_16 ? false : !fEnabled)
        && (sv <= SettingsVersion_v1_16 ? fEnabledIn : !fEnabledIn)
        && (sv <= SettingsVersion_v1_16 ? fEnabledOut : !fEnabledOut)
        && fEnabledOut == true
        && controllerType == AudioControllerType_AC97
        && codecType == AudioCodecType_STAC9700
        && properties.size() == 0;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool AudioAdapter::operator==(const AudioAdapter &a) const
{
    return (this == &a)
        || (   fEnabled        == a.fEnabled
            && fEnabledIn      == a.fEnabledIn
            && fEnabledOut     == a.fEnabledOut
            && controllerType  == a.controllerType
            && codecType       == a.codecType
            && driverType      == a.driverType
            && properties      == a.properties);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
SharedFolder::SharedFolder() :
    fWritable(false),
    fAutoMount(false)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool SharedFolder::operator==(const SharedFolder &g) const
{
    return (this == &g)
        || (   strName           == g.strName
            && strHostPath       == g.strHostPath
            && fWritable         == g.fWritable
            && fAutoMount        == g.fAutoMount
            && strAutoMountPoint == g.strAutoMountPoint);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
GuestProperty::GuestProperty() :
    timestamp(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool GuestProperty::operator==(const GuestProperty &g) const
{
    return (this == &g)
        || (   strName           == g.strName
            && strValue          == g.strValue
            && timestamp         == g.timestamp
            && strFlags          == g.strFlags);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
CpuIdLeaf::CpuIdLeaf() :
    idx(UINT32_MAX),
    idxSub(0),
    uEax(0),
    uEbx(0),
    uEcx(0),
    uEdx(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool CpuIdLeaf::operator==(const CpuIdLeaf &c) const
{
    return (this == &c)
        || (   idx      == c.idx
            && idxSub   == c.idxSub
            && uEax     == c.uEax
            && uEbx     == c.uEbx
            && uEcx     == c.uEcx
            && uEdx     == c.uEdx);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
Cpu::Cpu() :
    ulId(UINT32_MAX)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Cpu::operator==(const Cpu &c) const
{
    return (this == &c)
        || (ulId      == c.ulId);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
BandwidthGroup::BandwidthGroup() :
    cMaxBytesPerSec(0),
    enmType(BandwidthGroupType_Null)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool BandwidthGroup::operator==(const BandwidthGroup &i) const
{
    return (this == &i)
        || (   strName      == i.strName
            && cMaxBytesPerSec == i.cMaxBytesPerSec
            && enmType      == i.enmType);
}

/**
 * IOSettings constructor.
 */
IOSettings::IOSettings() :
    fIOCacheEnabled(true),
    ulIOCacheSize(5)
{
}

/**
 * Check if all IO Cache settings have default values.
 */
bool IOSettings::areIOCacheDefaultSettings() const
{
    return fIOCacheEnabled
        && ulIOCacheSize == 5;
}

/**
 * Check if all settings have default values.
 */
bool IOSettings::areDefaultSettings() const
{
    return areIOCacheDefaultSettings()
        && llBandwidthGroups.size() == 0;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool IOSettings::operator==(const IOSettings &i) const
{
    return (this == &i)
        || (   fIOCacheEnabled   == i.fIOCacheEnabled
            && ulIOCacheSize     == i.ulIOCacheSize
            && llBandwidthGroups == i.llBandwidthGroups);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
HostPCIDeviceAttachment::HostPCIDeviceAttachment() :
    uHostAddress(0),
    uGuestAddress(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool HostPCIDeviceAttachment::operator==(const HostPCIDeviceAttachment &a) const
{
    return (this == &a)
        || (   uHostAddress   == a.uHostAddress
            && uGuestAddress  == a.uGuestAddress
            && strDeviceName  == a.strDeviceName);
}


/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
Hardware::Hardware() :
    strVersion("1"),
    fHardwareVirt(true),
    fNestedPaging(true),
    fVPID(true),
    fUnrestrictedExecution(true),
    fHardwareVirtForce(false),
    fUseNativeApi(false),
    fTripleFaultReset(false),
    fPAE(false),
    fAPIC(true),
    fX2APIC(false),
    fIBPBOnVMExit(false),
    fIBPBOnVMEntry(false),
    fSpecCtrl(false),
    fSpecCtrlByHost(false),
    fL1DFlushOnSched(true),
    fL1DFlushOnVMEntry(false),
    fMDSClearOnSched(true),
    fMDSClearOnVMEntry(false),
    fNestedHWVirt(false),
    fVirtVmsaveVmload(true),
    enmLongMode(HC_ARCH_BITS == 64 ? Hardware::LongMode_Enabled : Hardware::LongMode_Disabled),
    cCPUs(1),
    fCpuHotPlug(false),
    fHPETEnabled(false),
    ulCpuExecutionCap(100),
    uCpuIdPortabilityLevel(0),
    strCpuProfile("host"),
    ulMemorySizeMB((uint32_t)-1),
    firmwareType(FirmwareType_BIOS),
    pointingHIDType(PointingHIDType_PS2Mouse),
    keyboardHIDType(KeyboardHIDType_PS2Keyboard),
    chipsetType(ChipsetType_PIIX3),
    iommuType(IommuType_None),
    paravirtProvider(ParavirtProvider_Legacy), // default for old VMs, for new ones it's ParavirtProvider_Default
    strParavirtDebug(""),
    fEmulatedUSBCardReader(false),
    clipboardMode(ClipboardMode_Disabled),
    fClipboardFileTransfersEnabled(false),
    dndMode(DnDMode_Disabled),
    ulMemoryBalloonSize(0),
    fPageFusionEnabled(false)
{
    mapBootOrder[0] = DeviceType_Floppy;
    mapBootOrder[1] = DeviceType_DVD;
    mapBootOrder[2] = DeviceType_HardDisk;

    /* The default value for PAE depends on the host:
     * - 64 bits host -> always true
     * - 32 bits host -> true for Windows & Darwin (masked off if the host cpu doesn't support it anyway)
     */
#if HC_ARCH_BITS == 64 || defined(RT_OS_WINDOWS) || defined(RT_OS_DARWIN)
    fPAE = true;
#endif

    /* The default value of large page supports depends on the host:
     * - 64 bits host -> true, unless it's Linux (pending further prediction work due to excessively expensive large page allocations)
     * - 32 bits host -> false
     */
#if HC_ARCH_BITS == 64 && !defined(RT_OS_LINUX)
    fLargePages = true;
#else
    /* Not supported on 32 bits hosts. */
    fLargePages = false;
#endif
}

/**
 * Check if all Paravirt settings have default values.
 */
bool Hardware::areParavirtDefaultSettings(SettingsVersion_T sv) const
{
    // 5.0 didn't save the paravirt settings if it is ParavirtProvider_Legacy,
    // so this default must be kept. Later versions don't save the setting if
    // it's at the default value.
    return (   (sv >= SettingsVersion_v1_16 && paravirtProvider == ParavirtProvider_Default)
            || (sv < SettingsVersion_v1_16 && paravirtProvider == ParavirtProvider_Legacy))
        && strParavirtDebug.isEmpty();
}

/**
 * Check if all Boot Order settings have default values.
 */
bool Hardware::areBootOrderDefaultSettings() const
{
    BootOrderMap::const_iterator it0 = mapBootOrder.find(0);
    BootOrderMap::const_iterator it1 = mapBootOrder.find(1);
    BootOrderMap::const_iterator it2 = mapBootOrder.find(2);
    BootOrderMap::const_iterator it3 = mapBootOrder.find(3);
    return    (   mapBootOrder.size() == 3
               || (   mapBootOrder.size() == 4
                   && (it3 != mapBootOrder.end() && it3->second == DeviceType_Null)))
           && (it0 != mapBootOrder.end() && it0->second == DeviceType_Floppy)
           && (it1 != mapBootOrder.end() && it1->second == DeviceType_DVD)
           && (it2 != mapBootOrder.end() && it2->second == DeviceType_HardDisk);
}

/**
 * Check if all Network Adapter settings have default values.
 */
bool Hardware::areAllNetworkAdaptersDefaultSettings(SettingsVersion_T sv) const
{
    for (NetworkAdaptersList::const_iterator it = llNetworkAdapters.begin();
         it != llNetworkAdapters.end();
         ++it)
    {
        if (!it->areDefaultSettings(sv))
            return false;
    }
    return true;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Hardware::operator==(const Hardware& h) const
{
    return (this == &h)
        || (   strVersion                     == h.strVersion
            && uuid                           == h.uuid
            && fHardwareVirt                  == h.fHardwareVirt
            && fNestedPaging                  == h.fNestedPaging
            && fLargePages                    == h.fLargePages
            && fVPID                          == h.fVPID
            && fUnrestrictedExecution         == h.fUnrestrictedExecution
            && fHardwareVirtForce             == h.fHardwareVirtForce
            && fUseNativeApi                  == h.fUseNativeApi
            && fPAE                           == h.fPAE
            && enmLongMode                    == h.enmLongMode
            && fTripleFaultReset              == h.fTripleFaultReset
            && fAPIC                          == h.fAPIC
            && fX2APIC                        == h.fX2APIC
            && fIBPBOnVMExit                  == h.fIBPBOnVMExit
            && fIBPBOnVMEntry                 == h.fIBPBOnVMEntry
            && fSpecCtrl                      == h.fSpecCtrl
            && fSpecCtrlByHost                == h.fSpecCtrlByHost
            && fL1DFlushOnSched               == h.fL1DFlushOnSched
            && fL1DFlushOnVMEntry             == h.fL1DFlushOnVMEntry
            && fMDSClearOnSched               == h.fMDSClearOnSched
            && fMDSClearOnVMEntry             == h.fMDSClearOnVMEntry
            && fNestedHWVirt                  == h.fNestedHWVirt
            && fVirtVmsaveVmload              == h.fVirtVmsaveVmload
            && cCPUs                          == h.cCPUs
            && fCpuHotPlug                    == h.fCpuHotPlug
            && ulCpuExecutionCap              == h.ulCpuExecutionCap
            && uCpuIdPortabilityLevel         == h.uCpuIdPortabilityLevel
            && strCpuProfile                  == h.strCpuProfile
            && fHPETEnabled                   == h.fHPETEnabled
            && llCpus                         == h.llCpus
            && llCpuIdLeafs                   == h.llCpuIdLeafs
            && ulMemorySizeMB                 == h.ulMemorySizeMB
            && mapBootOrder                   == h.mapBootOrder
            && firmwareType                   == h.firmwareType
            && pointingHIDType                == h.pointingHIDType
            && keyboardHIDType                == h.keyboardHIDType
            && chipsetType                    == h.chipsetType
            && iommuType                      == h.iommuType
            && paravirtProvider               == h.paravirtProvider
            && strParavirtDebug               == h.strParavirtDebug
            && fEmulatedUSBCardReader         == h.fEmulatedUSBCardReader
            && vrdeSettings                   == h.vrdeSettings
            && biosSettings                   == h.biosSettings
            && nvramSettings                  == h.nvramSettings
            && graphicsAdapter                == h.graphicsAdapter
            && usbSettings                    == h.usbSettings
            && tpmSettings                    == h.tpmSettings
            && llNetworkAdapters              == h.llNetworkAdapters
            && llSerialPorts                  == h.llSerialPorts
            && llParallelPorts                == h.llParallelPorts
            && audioAdapter                   == h.audioAdapter
            && storage                        == h.storage
            && llSharedFolders                == h.llSharedFolders
            && clipboardMode                  == h.clipboardMode
            && fClipboardFileTransfersEnabled == h.fClipboardFileTransfersEnabled
            && dndMode                        == h.dndMode
            && ulMemoryBalloonSize            == h.ulMemoryBalloonSize
            && fPageFusionEnabled             == h.fPageFusionEnabled
            && llGuestProperties              == h.llGuestProperties
            && ioSettings                     == h.ioSettings
            && pciAttachments                 == h.pciAttachments
            && strDefaultFrontend             == h.strDefaultFrontend);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
AttachedDevice::AttachedDevice() :
    deviceType(DeviceType_Null),
    fPassThrough(false),
    fTempEject(false),
    fNonRotational(false),
    fDiscard(false),
    fHotPluggable(false),
    lPort(0),
    lDevice(0)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool AttachedDevice::operator==(const AttachedDevice &a) const
{
    return (this == &a)
        || (   deviceType                == a.deviceType
            && fPassThrough              == a.fPassThrough
            && fTempEject                == a.fTempEject
            && fNonRotational            == a.fNonRotational
            && fDiscard                  == a.fDiscard
            && fHotPluggable             == a.fHotPluggable
            && lPort                     == a.lPort
            && lDevice                   == a.lDevice
            && uuid                      == a.uuid
            && strHostDriveSrc           == a.strHostDriveSrc
            && strBwGroup                == a.strBwGroup);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
StorageController::StorageController() :
    storageBus(StorageBus_IDE),
    controllerType(StorageControllerType_PIIX3),
    ulPortCount(2),
    ulInstance(0),
    fUseHostIOCache(true),
    fBootable(true)
{
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool StorageController::operator==(const StorageController &s) const
{
    return (this == &s)
        || (   strName                   == s.strName
            && storageBus                == s.storageBus
            && controllerType            == s.controllerType
            && ulPortCount               == s.ulPortCount
            && ulInstance                == s.ulInstance
            && fUseHostIOCache           == s.fUseHostIOCache
            && llAttachedDevices         == s.llAttachedDevices);
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Storage::operator==(const Storage &s) const
{
    return (this == &s)
        || (llStorageControllers == s.llStorageControllers);            // deep compare
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
Debugging::Debugging() :
    fTracingEnabled(false),
    fAllowTracingToAccessVM(false),
    strTracingConfig(),
    enmDbgProvider(GuestDebugProvider_None),
    enmIoProvider(GuestDebugIoProvider_None),
    strAddress(),
    ulPort(0)
{
}

/**
 * Check if all settings have default values.
 */
bool Debugging::areDefaultSettings() const
{
    return !fTracingEnabled
        && !fAllowTracingToAccessVM
        && strTracingConfig.isEmpty()
        && enmDbgProvider == GuestDebugProvider_None
        && enmIoProvider == GuestDebugIoProvider_None
        && strAddress.isEmpty()
        && ulPort == 0;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Debugging::operator==(const Debugging &d) const
{
    return (this == &d)
        || (   fTracingEnabled          == d.fTracingEnabled
            && fAllowTracingToAccessVM  == d.fAllowTracingToAccessVM
            && strTracingConfig         == d.strTracingConfig
            && enmDbgProvider           == d.enmDbgProvider
            && enmIoProvider            == d.enmIoProvider
            && strAddress               == d.strAddress
            && ulPort                   == d.ulPort);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
Autostart::Autostart() :
    fAutostartEnabled(false),
    uAutostartDelay(0),
    enmAutostopType(AutostopType_Disabled)
{
}

/**
 * Check if all settings have default values.
 */
bool Autostart::areDefaultSettings() const
{
    return !fAutostartEnabled
        && !uAutostartDelay
        && enmAutostopType == AutostopType_Disabled;
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Autostart::operator==(const Autostart &a) const
{
    return (this == &a)
        || (   fAutostartEnabled == a.fAutostartEnabled
            && uAutostartDelay   == a.uAutostartDelay
            && enmAutostopType   == a.enmAutostopType);
}

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
Snapshot::Snapshot()
{
    RTTimeSpecSetNano(&timestamp, 0);
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool Snapshot::operator==(const Snapshot &s) const
{
    return (this == &s)
        || (   uuid                  == s.uuid
            && strName               == s.strName
            && strDescription        == s.strDescription
            && RTTimeSpecIsEqual(&timestamp, &s.timestamp)
            && strStateFile          == s.strStateFile
            && hardware              == s.hardware                  // deep compare
            && recordingSettings     == s.recordingSettings         // deep compare
            && llChildSnapshots      == s.llChildSnapshots          // deep compare
            && debugging             == s.debugging
            && autostart             == s.autostart);
}

const struct Snapshot settings::Snapshot::Empty; /* default ctor is OK */

/**
 * Constructor. Needs to set sane defaults which stand the test of time.
 */
MachineUserData::MachineUserData() :
    fDirectoryIncludesUUID(false),
    fNameSync(true),
    fTeleporterEnabled(false),
    uTeleporterPort(0),
    fRTCUseUTC(false),
    enmVMPriority(VMProcPriority_Default)
{
    llGroups.push_back("/");
}

/**
 * Comparison operator. This gets called from MachineConfigFile::operator==,
 * which in turn gets called from Machine::saveSettings to figure out whether
 * machine settings have really changed and thus need to be written out to disk.
 */
bool MachineUserData::operator==(const MachineUserData &c) const
{
    return (this == &c)
        || (   strName                    == c.strName
            && fDirectoryIncludesUUID     == c.fDirectoryIncludesUUID
            && fNameSync                  == c.fNameSync
            && strDescription             == c.strDescription
            && llGroups                   == c.llGroups
            && strOsType                  == c.strOsType
            && strSnapshotFolder          == c.strSnapshotFolder
            && fTeleporterEnabled         == c.fTeleporterEnabled
            && uTeleporterPort            == c.uTeleporterPort
            && strTeleporterAddress       == c.strTeleporterAddress
            && strTeleporterPassword      == c.strTeleporterPassword
            && fRTCUseUTC                 == c.fRTCUseUTC
            && ovIcon                     == c.ovIcon
            && enmVMPriority              == c.enmVMPriority);
}


////////////////////////////////////////////////////////////////////////////////
//
// MachineConfigFile
//
////////////////////////////////////////////////////////////////////////////////

/**
 * Constructor.
 *
 * If pstrFilename is != NULL, this reads the given settings file into the member
 * variables and various substructures and lists. Otherwise, the member variables
 * are initialized with default values.
 *
 * Throws variants of xml::Error for I/O, XML and logical content errors, which
 * the caller should catch; if this constructor does not throw, then the member
 * variables contain meaningful values (either from the file or defaults).
 *
 * @param pstrFilename
 * @param pCryptoIf             Pointer to the cryptographic interface, required for an encrypted machine config.
 * @param pszPassword           The password to use for an encrypted machine config.
 */
MachineConfigFile::MachineConfigFile(const Utf8Str *pstrFilename, PCVBOXCRYPTOIF pCryptoIf, const char *pszPassword)
    : ConfigFileBase(pstrFilename),
      enmParseState(ParseState_NotParsed),
      fCurrentStateModified(true),
      fAborted(false)
{
    RTTimeNow(&timeLastStateChange);

    if (pstrFilename)
    {
        // the ConfigFileBase constructor has loaded the XML file, so now
        // we need only analyze what is in there

        xml::NodesLoop nlRootChildren(*m->pelmRoot);
        const xml::ElementNode *pelmRootChild;
        while ((pelmRootChild = nlRootChildren.forAllNodes()))
        {
            if (pelmRootChild->nameEquals("MachineEncrypted"))
                readMachineEncrypted(*pelmRootChild, pCryptoIf, pszPassword);
            if (pelmRootChild->nameEquals("Machine"))
                readMachine(*pelmRootChild);
        }

        // clean up memory allocated by XML engine
        clearDocument();

        if (enmParseState == ParseState_NotParsed)
            enmParseState = ParseState_Parsed;
    }
}

/**
 * Public routine which returns true if this machine config file can have its
 * own media registry (which is true for settings version v1.11 and higher,
 * i.e. files created by VirtualBox 4.0 and higher).
 * @return
 */
bool MachineConfigFile::canHaveOwnMediaRegistry() const
{
    return (m->sv >= SettingsVersion_v1_11);
}

/**
 * Public routine which copies encryption settings. Used by Machine::saveSettings
 * so that the encryption settings do not get lost when a copy of the Machine settings
 * file is made to see if settings have actually changed.
 * @param other
 */
void MachineConfigFile::copyEncryptionSettingsFrom(const MachineConfigFile &other)
{
    strKeyId    = other.strKeyId;
    strKeyStore = other.strKeyStore;
}

/**
 * Public routine which allows for importing machine XML from an external DOM tree.
 * Use this after having called the constructor with a NULL argument.
 *
 * This is used by the OVF code if a <vbox:Machine> element has been encountered
 * in an OVF VirtualSystem element.
 *
 * @param elmMachine
 */
void MachineConfigFile::importMachineXML(const xml::ElementNode &elmMachine)
{
    // Ideally the version should be mandatory, but since VirtualBox didn't
    // care about it until 5.1 came with different defaults, there are OVF
    // files created by magicians (not using VirtualBox, which always wrote it)
    // which lack this information. Let's hope that they learn to add the
    // version when they switch to the newer settings style/defaults of 5.1.
    if (!(elmMachine.getAttributeValue("version", m->strSettingsVersionFull)))
        m->strSettingsVersionFull = VBOX_XML_IMPORT_VERSION_FULL;

    LogRel(("Import settings with version \"%s\"\n", m->strSettingsVersionFull.c_str()));

    m->sv = parseVersion(m->strSettingsVersionFull, &elmMachine);

    // remember the settings version we read in case it gets upgraded later,
    // so we know when to make backups
    m->svRead = m->sv;

    readMachine(elmMachine);
}

/**
 * Comparison operator. This gets called from Machine::saveSettings to figure out
 * whether machine settings have really changed and thus need to be written out to disk.
 *
 * Even though this is called operator==, this does NOT compare all fields; the "equals"
 * should be understood as "has the same machine config as". The following fields are
 * NOT compared:
 *      -- settings versions and file names inherited from ConfigFileBase;
 *      -- fCurrentStateModified because that is considered separately in Machine::saveSettings!!
 *
 * The "deep" comparisons marked below will invoke the operator== functions of the
 * structs defined in this file, which may in turn go into comparing lists of
 * other structures. As a result, invoking this can be expensive, but it's
 * less expensive than writing out XML to disk.
 */
bool MachineConfigFile::operator==(const MachineConfigFile &c) const
{
    return (this == &c)
        || (   uuid                       == c.uuid
            && machineUserData            == c.machineUserData
            && strStateFile               == c.strStateFile
            && uuidCurrentSnapshot        == c.uuidCurrentSnapshot
            // skip fCurrentStateModified!
            && RTTimeSpecIsEqual(&timeLastStateChange, &c.timeLastStateChange)
            && fAborted                   == c.fAborted
            && hardwareMachine            == c.hardwareMachine      // this one's deep
            && mediaRegistry              == c.mediaRegistry        // this one's deep
            // skip mapExtraDataItems! there is no old state available as it's always forced
            && llFirstSnapshot            == c.llFirstSnapshot     // this one's deep
            && recordingSettings          == c.recordingSettings   // this one's deep
            && strKeyId                   == c.strKeyId
            && strKeyStore                == c.strKeyStore
            && strStateKeyId              == c.strStateKeyId
            && strStateKeyStore           == c.strStateKeyStore
            && strLogKeyId                == c.strLogKeyId
            && strLogKeyStore             == c.strLogKeyStore);
}

/**
 * Called from MachineConfigFile::readHardware() to read cpu information.
 * @param elmCpu
 * @param ll
 */
void MachineConfigFile::readCpuTree(const xml::ElementNode &elmCpu,
                                    CpuList &ll)
{
    xml::NodesLoop nl1(elmCpu, "Cpu");
    const xml::ElementNode *pelmCpu;
    while ((pelmCpu = nl1.forAllNodes()))
    {
        Cpu cpu;

        if (!pelmCpu->getAttributeValue("id", cpu.ulId))
            throw ConfigFileError(this, pelmCpu, N_("Required Cpu/@id attribute is missing"));

        ll.push_back(cpu);
    }
}

/**
 * Called from MachineConfigFile::readHardware() to cpuid information.
 * @param elmCpuid
 * @param ll
 */
void MachineConfigFile::readCpuIdTree(const xml::ElementNode &elmCpuid,
                                      CpuIdLeafsList &ll)
{
    xml::NodesLoop nl1(elmCpuid, "CpuIdLeaf");
    const xml::ElementNode *pelmCpuIdLeaf;
    while ((pelmCpuIdLeaf = nl1.forAllNodes()))
    {
        CpuIdLeaf leaf;

        if (!pelmCpuIdLeaf->getAttributeValue("id", leaf.idx))
            throw ConfigFileError(this, pelmCpuIdLeaf, N_("Required CpuId/@id attribute is missing"));

        if (!pelmCpuIdLeaf->getAttributeValue("subleaf", leaf.idxSub))
            leaf.idxSub = 0;
        pelmCpuIdLeaf->getAttributeValue("eax", leaf.uEax);
        pelmCpuIdLeaf->getAttributeValue("ebx", leaf.uEbx);
        pelmCpuIdLeaf->getAttributeValue("ecx", leaf.uEcx);
        pelmCpuIdLeaf->getAttributeValue("edx", leaf.uEdx);

        ll.push_back(leaf);
    }
}

/**
 * Called from MachineConfigFile::readHardware() to network information.
 * @param elmNetwork
 * @param ll
 */
void MachineConfigFile::readNetworkAdapters(const xml::ElementNode &elmNetwork,
                                            NetworkAdaptersList &ll)
{
    xml::NodesLoop nl1(elmNetwork, "Adapter");
    const xml::ElementNode *pelmAdapter;
    while ((pelmAdapter = nl1.forAllNodes()))
    {
        NetworkAdapter nic;

        if (m->sv >= SettingsVersion_v1_16)
        {
            /* Starting with VirtualBox 5.1 the default is cable connected and
             * PCnet-FAST III. Needs to match NetworkAdapter.areDefaultSettings(). */
            nic.fCableConnected = true;
            nic.type = NetworkAdapterType_Am79C973;
        }

        if (!pelmAdapter->getAttributeValue("slot", nic.ulSlot))
            throw ConfigFileError(this, pelmAdapter, N_("Required Adapter/@slot attribute is missing"));

        Utf8Str strTemp;
        if (pelmAdapter->getAttributeValue("type", strTemp))
        {
            if (strTemp == "Am79C970A")
                nic.type = NetworkAdapterType_Am79C970A;
            else if (strTemp == "Am79C973")
                nic.type = NetworkAdapterType_Am79C973;
            else if (strTemp == "Am79C960")
                nic.type = NetworkAdapterType_Am79C960;
            else if (strTemp == "82540EM")
                nic.type = NetworkAdapterType_I82540EM;
            else if (strTemp == "82543GC")
                nic.type = NetworkAdapterType_I82543GC;
            else if (strTemp == "82545EM")
                nic.type = NetworkAdapterType_I82545EM;
            else if (strTemp == "virtio")
                nic.type = NetworkAdapterType_Virtio;
            else if (strTemp == "NE1000")
                nic.type = NetworkAdapterType_NE1000;
            else if (strTemp == "NE2000")
                nic.type = NetworkAdapterType_NE2000;
            else if (strTemp == "WD8003")
                nic.type = NetworkAdapterType_WD8003;
            else if (strTemp == "WD8013")
                nic.type = NetworkAdapterType_WD8013;
            else if (strTemp == "3C503")
                nic.type = NetworkAdapterType_ELNK2;
            else if (strTemp == "3C501")
                nic.type = NetworkAdapterType_ELNK1;
            else
                throw ConfigFileError(this, pelmAdapter, N_("Invalid value '%s' in Adapter/@type attribute"), strTemp.c_str());
        }

        pelmAdapter->getAttributeValue("enabled", nic.fEnabled);
        pelmAdapter->getAttributeValue("MACAddress", nic.strMACAddress);
        pelmAdapter->getAttributeValue("cable", nic.fCableConnected);
        pelmAdapter->getAttributeValue("speed", nic.ulLineSpeed);

        if (pelmAdapter->getAttributeValue("promiscuousModePolicy", strTemp))
        {
            if (strTemp == "Deny")
                nic.enmPromiscModePolicy = NetworkAdapterPromiscModePolicy_Deny;
            else if (strTemp == "AllowNetwork")
                nic.enmPromiscModePolicy = NetworkAdapterPromiscModePolicy_AllowNetwork;
            else if (strTemp == "AllowAll")
                nic.enmPromiscModePolicy = NetworkAdapterPromiscModePolicy_AllowAll;
            else
                throw ConfigFileError(this, pelmAdapter,
                                      N_("Invalid value '%s' in Adapter/@promiscuousModePolicy attribute"), strTemp.c_str());
        }

        pelmAdapter->getAttributeValue("trace", nic.fTraceEnabled);
        pelmAdapter->getAttributeValue("tracefile", nic.strTraceFile);
        pelmAdapter->getAttributeValue("bootPriority", nic.ulBootPriority);
        pelmAdapter->getAttributeValue("bandwidthGroup", nic.strBandwidthGroup);

        xml::ElementNodesList llNetworkModes;
        pelmAdapter->getChildElements(llNetworkModes);
        xml::ElementNodesList::iterator it;
        /* We should have only active mode descriptor and disabled modes set */
        if (llNetworkModes.size() > 2)
        {
            throw ConfigFileError(this, pelmAdapter, N_("Invalid number of modes ('%d') attached to Adapter attribute"), llNetworkModes.size());
        }
        for (it = llNetworkModes.begin(); it != llNetworkModes.end(); ++it)
        {
            const xml::ElementNode *pelmNode = *it;
            if (pelmNode->nameEquals("DisabledModes"))
            {
                xml::ElementNodesList llDisabledNetworkModes;
                xml::ElementNodesList::iterator itDisabled;
                pelmNode->getChildElements(llDisabledNetworkModes);
                /* run over disabled list and load settings */
                for (itDisabled = llDisabledNetworkModes.begin();
                     itDisabled != llDisabledNetworkModes.end(); ++itDisabled)
                {
                    const xml::ElementNode *pelmDisabledNode = *itDisabled;
                    readAttachedNetworkMode(*pelmDisabledNode, false, nic);
                }
            }
            else
                readAttachedNetworkMode(*pelmNode, true, nic);
        }
        // else: default is NetworkAttachmentType_Null

        ll.push_back(nic);
    }
}

void MachineConfigFile::readAttachedNetworkMode(const xml::ElementNode &elmMode, bool fEnabled, NetworkAdapter &nic)
{
    NetworkAttachmentType_T enmAttachmentType = NetworkAttachmentType_Null;

    if (elmMode.nameEquals("NAT"))
    {
        enmAttachmentType = NetworkAttachmentType_NAT;

        elmMode.getAttributeValue("network", nic.nat.strNetwork);
        elmMode.getAttributeValue("hostip", nic.nat.strBindIP);
        elmMode.getAttributeValue("mtu", nic.nat.u32Mtu);
        elmMode.getAttributeValue("sockrcv", nic.nat.u32SockRcv);
        elmMode.getAttributeValue("socksnd", nic.nat.u32SockSnd);
        elmMode.getAttributeValue("tcprcv", nic.nat.u32TcpRcv);
        elmMode.getAttributeValue("tcpsnd", nic.nat.u32TcpSnd);
        elmMode.getAttributeValue("localhost-reachable", nic.nat.fLocalhostReachable);
        const xml::ElementNode *pelmDNS;
        if ((pelmDNS = elmMode.findChildElement("DNS")))
        {
            pelmDNS->getAttributeValue("pass-domain", nic.nat.fDNSPassDomain);
            pelmDNS->getAttributeValue("use-proxy", nic.nat.fDNSProxy);
            pelmDNS->getAttributeValue("use-host-resolver", nic.nat.fDNSUseHostResolver);
        }
        const xml::ElementNode *pelmAlias;
        if ((pelmAlias = elmMode.findChildElement("Alias")))
        {
            pelmAlias->getAttributeValue("logging", nic.nat.fAliasLog);
            pelmAlias->getAttributeValue("proxy-only", nic.nat.fAliasProxyOnly);
            pelmAlias->getAttributeValue("use-same-ports", nic.nat.fAliasUseSamePorts);
        }
        const xml::ElementNode *pelmTFTP;
        if ((pelmTFTP = elmMode.findChildElement("TFTP")))
        {
            pelmTFTP->getAttributeValue("prefix", nic.nat.strTFTPPrefix);
            pelmTFTP->getAttributeValue("boot-file", nic.nat.strTFTPBootFile);
            pelmTFTP->getAttributeValue("next-server", nic.nat.strTFTPNextServer);
        }

        readNATForwardRulesMap(elmMode, nic.nat.mapRules);
    }
    else if (   elmMode.nameEquals("HostInterface")
             || elmMode.nameEquals("BridgedInterface"))
    {
        enmAttachmentType = NetworkAttachmentType_Bridged;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strBridgedName);
    }
    else if (elmMode.nameEquals("InternalNetwork"))
    {
        enmAttachmentType = NetworkAttachmentType_Internal;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strInternalNetworkName);
    }
    else if (elmMode.nameEquals("HostOnlyInterface"))
    {
        enmAttachmentType = NetworkAttachmentType_HostOnly;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strHostOnlyName);
    }
#ifdef VBOX_WITH_VMNET
    else if (elmMode.nameEquals("HostOnlyNetwork"))
    {
        enmAttachmentType = NetworkAttachmentType_HostOnlyNetwork;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strHostOnlyNetworkName);
    }
#endif /* VBOX_WITH_VMNET */
    else if (elmMode.nameEquals("GenericInterface"))
    {
        enmAttachmentType = NetworkAttachmentType_Generic;

        elmMode.getAttributeValue("driver", nic.strGenericDriver);  // optional network attachment driver

        // get all properties
        xml::NodesLoop nl(elmMode);
        const xml::ElementNode *pelmModeChild;
        while ((pelmModeChild = nl.forAllNodes()))
        {
            if (pelmModeChild->nameEquals("Property"))
            {
                Utf8Str strPropName, strPropValue;
                if (   pelmModeChild->getAttributeValue("name", strPropName)
                    && pelmModeChild->getAttributeValue("value", strPropValue) )
                    nic.genericProperties[strPropName] = strPropValue;
                else
                    throw ConfigFileError(this, pelmModeChild, N_("Required GenericInterface/Property/@name or @value attribute is missing"));
            }
        }
    }
    else if (elmMode.nameEquals("NATNetwork"))
    {
        enmAttachmentType = NetworkAttachmentType_NATNetwork;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strNATNetworkName);
    }
    else if (elmMode.nameEquals("VDE"))
    {
        // inofficial hack (VDE networking was never part of the official
        // settings, so it's not mentioned in VirtualBox-settings.xsd)
        enmAttachmentType = NetworkAttachmentType_Generic;

        com::Utf8Str strVDEName;
        elmMode.getAttributeValue("network", strVDEName);   // optional network name
        nic.strGenericDriver = "VDE";
        nic.genericProperties["network"] = strVDEName;
    }
#ifdef VBOX_WITH_VMNET
    else if (elmMode.nameEquals("HostOnlyNetwork"))
    {
        enmAttachmentType = NetworkAttachmentType_HostOnly;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strHostOnlyNetworkName);
    }
#endif /* VBOX_WITH_VMNET */
#ifdef VBOX_WITH_CLOUD_NET
    else if (elmMode.nameEquals("CloudNetwork"))
    {
        enmAttachmentType = NetworkAttachmentType_Cloud;

        // optional network name, cannot be required or we have trouble with
        // settings which are saved before configuring the network name
        elmMode.getAttributeValue("name", nic.strCloudNetworkName);
    }
#endif /* VBOX_WITH_CLOUD_NET */

    if (fEnabled && enmAttachmentType != NetworkAttachmentType_Null)
        nic.mode = enmAttachmentType;
}

/**
 * Called from MachineConfigFile::readHardware() to read serial port information.
 * @param elmUART
 * @param ll
 */
void MachineConfigFile::readSerialPorts(const xml::ElementNode &elmUART,
                                        SerialPortsList &ll)
{
    xml::NodesLoop nl1(elmUART, "Port");
    const xml::ElementNode *pelmPort;
    while ((pelmPort = nl1.forAllNodes()))
    {
        SerialPort port;
        if (!pelmPort->getAttributeValue("slot", port.ulSlot))
            throw ConfigFileError(this, pelmPort, N_("Required UART/Port/@slot attribute is missing"));

        // slot must be unique
        for (SerialPortsList::const_iterator it = ll.begin();
             it != ll.end();
             ++it)
            if ((*it).ulSlot == port.ulSlot)
                throw ConfigFileError(this, pelmPort, N_("Invalid value %RU32 in UART/Port/@slot attribute: value is not unique"), port.ulSlot);

        if (!pelmPort->getAttributeValue("enabled", port.fEnabled))
            throw ConfigFileError(this, pelmPort, N_("Required UART/Port/@enabled attribute is missing"));
        if (!pelmPort->getAttributeValue("IOBase", port.ulIOBase))
            throw ConfigFileError(this, pelmPort, N_("Required UART/Port/@IOBase attribute is missing"));
        if (!pelmPort->getAttributeValue("IRQ", port.ulIRQ))
            throw ConfigFileError(this, pelmPort, N_("Required UART/Port/@IRQ attribute is missing"));

        Utf8Str strPortMode;
        if (!pelmPort->getAttributeValue("hostMode", strPortMode))
            throw ConfigFileError(this, pelmPort, N_("Required UART/Port/@hostMode attribute is missing"));
        if (strPortMode == "RawFile")
            port.portMode = PortMode_RawFile;
        else if (strPortMode == "HostPipe")
            port.portMode = PortMode_HostPipe;
        else if (strPortMode == "HostDevice")
            port.portMode = PortMode_HostDevice;
        else if (strPortMode == "Disconnected")
            port.portMode = PortMode_Disconnected;
        else if (strPortMode == "TCP")
            port.portMode = PortMode_TCP;
        else
            throw ConfigFileError(this, pelmPort, N_("Invalid value '%s' in UART/Port/@hostMode attribute"), strPortMode.c_str());

        pelmPort->getAttributeValue("path", port.strPath);
        pelmPort->getAttributeValue("server", port.fServer);

        Utf8Str strUartType;
        if (pelmPort->getAttributeValue("uartType", strUartType))
        {
            if (strUartType == "16450")
                port.uartType = UartType_U16450;
            else if (strUartType == "16550A")
                port.uartType = UartType_U16550A;
            else if (strUartType == "16750")
                port.uartType = UartType_U16750;
            else
                throw ConfigFileError(this, pelmPort, N_("Invalid value '%s' in UART/Port/@uartType attribute"), strUartType.c_str());
        }

        ll.push_back(port);
    }
}

/**
 * Called from MachineConfigFile::readHardware() to read parallel port information.
 * @param elmLPT
 * @param ll
 */
void MachineConfigFile::readParallelPorts(const xml::ElementNode &elmLPT,
                                          ParallelPortsList &ll)
{
    xml::NodesLoop nl1(elmLPT, "Port");
    const xml::ElementNode *pelmPort;
    while ((pelmPort = nl1.forAllNodes()))
    {
        ParallelPort port;
        if (!pelmPort->getAttributeValue("slot", port.ulSlot))
            throw ConfigFileError(this, pelmPort, N_("Required LPT/Port/@slot attribute is missing"));

        // slot must be unique
        for (ParallelPortsList::const_iterator it = ll.begin();
             it != ll.end();
             ++it)
            if ((*it).ulSlot == port.ulSlot)
                throw ConfigFileError(this, pelmPort, N_("Invalid value %RU32 in LPT/Port/@slot attribute: value is not unique"), port.ulSlot);

        if (!pelmPort->getAttributeValue("enabled", port.fEnabled))
            throw ConfigFileError(this, pelmPort, N_("Required LPT/Port/@enabled attribute is missing"));
        if (!pelmPort->getAttributeValue("IOBase", port.ulIOBase))
            throw ConfigFileError(this, pelmPort, N_("Required LPT/Port/@IOBase attribute is missing"));
        if (!pelmPort->getAttributeValue("IRQ", port.ulIRQ))
            throw ConfigFileError(this, pelmPort, N_("Required LPT/Port/@IRQ attribute is missing"));

        pelmPort->getAttributeValue("path", port.strPath);

        ll.push_back(port);
    }
}

/**
 * Called from MachineConfigFile::readHardware() to read audio adapter information
 * and maybe fix driver information depending on the current host hardware.
 *
 * @param elmAudioAdapter "AudioAdapter" XML element.
 * @param aa
 */
void MachineConfigFile::readAudioAdapter(const xml::ElementNode &elmAudioAdapter,
                                         AudioAdapter &aa)
{
    if (m->sv >= SettingsVersion_v1_15)
    {
        // get all properties
        xml::NodesLoop nl1(elmAudioAdapter, "Property");
        const xml::ElementNode *pelmModeChild;
        while ((pelmModeChild = nl1.forAllNodes()))
        {
            Utf8Str strPropName, strPropValue;
            if (   pelmModeChild->getAttributeValue("name", strPropName)
                && pelmModeChild->getAttributeValue("value", strPropValue) )
                aa.properties[strPropName] = strPropValue;
            else
                throw ConfigFileError(this, pelmModeChild, N_("Required AudioAdapter/Property/@name or @value attribute "
                                                              "is missing"));
        }
    }

    elmAudioAdapter.getAttributeValue("enabled", aa.fEnabled);
    elmAudioAdapter.getAttributeValue("enabledIn", aa.fEnabledIn);
    elmAudioAdapter.getAttributeValue("enabledOut", aa.fEnabledOut);

    Utf8Str strTemp;
    if (elmAudioAdapter.getAttributeValue("controller", strTemp))
    {
        if (strTemp == "SB16")
            aa.controllerType = AudioControllerType_SB16;
        else if (strTemp == "AC97")
            aa.controllerType = AudioControllerType_AC97;
        else if (strTemp == "HDA")
            aa.controllerType = AudioControllerType_HDA;
        else
            throw ConfigFileError(this, &elmAudioAdapter, N_("Invalid value '%s' in AudioAdapter/@controller attribute"), strTemp.c_str());
    }

    if (elmAudioAdapter.getAttributeValue("codec", strTemp))
    {
        if (strTemp == "SB16")
            aa.codecType = AudioCodecType_SB16;
        else if (strTemp == "STAC9700")
            aa.codecType = AudioCodecType_STAC9700;
        else if (strTemp == "AD1980")
            aa.codecType = AudioCodecType_AD1980;
        else if (strTemp == "STAC9221")
            aa.codecType = AudioCodecType_STAC9221;
        else
            throw ConfigFileError(this, &elmAudioAdapter, N_("Invalid value '%s' in AudioAdapter/@codec attribute"), strTemp.c_str());
    }
    else
    {
        /* No codec attribute provided; use defaults. */
        switch (aa.controllerType)
        {
            case AudioControllerType_AC97:
                aa.codecType = AudioCodecType_STAC9700;
                break;
            case AudioControllerType_SB16:
                aa.codecType = AudioCodecType_SB16;
                break;
            case AudioControllerType_HDA:
                aa.codecType = AudioCodecType_STAC9221;
                break;
            default:
                Assert(false);  /* We just checked the controller type above. */
        }
    }

    if (elmAudioAdapter.getAttributeValue("driver", strTemp))
    {
        // settings before 1.3 used lower case so make sure this is case-insensitive
        strTemp.toUpper();
        if (strTemp == "DEFAULT") /* Keep this to be backwards compatible for settings < r152556. */
            aa.driverType = AudioDriverType_Default;
        else if (strTemp == "NULL")
            aa.driverType = AudioDriverType_Null;
        else if (strTemp == "WAS")
            aa.driverType = AudioDriverType_WAS;
        else if (strTemp == "WINMM")
            aa.driverType = AudioDriverType_WinMM;
        else if ( (strTemp == "DIRECTSOUND") || (strTemp == "DSOUND") )
            aa.driverType = AudioDriverType_DirectSound;
        else if (strTemp == "SOLAUDIO") /* Deprecated -- Solaris will use OSS by default now. */
            aa.driverType = AudioDriverType_SolAudio;
        else if (strTemp == "ALSA")
            aa.driverType = AudioDriverType_ALSA;
        else if (strTemp == "PULSE")
            aa.driverType = AudioDriverType_Pulse;
        else if (strTemp == "OSS")
            aa.driverType = AudioDriverType_OSS;
        else if (strTemp == "COREAUDIO")
            aa.driverType = AudioDriverType_CoreAudio;
        else if (strTemp == "MMPM") /* Deprecated; only kept for backwards compatibility. */
            aa.driverType = AudioDriverType_MMPM;
        else
            throw ConfigFileError(this, &elmAudioAdapter, N_("Invalid value '%s' in AudioAdapter/@driver attribute"), strTemp.c_str());

        /* When loading settings >= 1.19 (VBox 7.0), the attribute "useDefault" will determine if the VM should use
         * the OS' default audio driver or not. This additional attribute is necessary in order to be backwards compatible
         * with older VBox versions. */
        bool fUseDefault = false;
        if (   elmAudioAdapter.getAttributeValue("useDefault", &fUseDefault) /* Overrides "driver" above (if set). */
            && fUseDefault)
            aa.driverType = AudioDriverType_Default;

        // now check if this is actually supported on the current host platform;
        // people might be opening a file created on a Windows host, and that
        // VM should still start on a Linux host
        if (!isAudioDriverAllowedOnThisHost(aa.driverType))
            aa.driverType = getHostDefaultAudioDriver();
    }
}

/**
 * Called from MachineConfigFile::readHardware() to read guest property information.
 * @param elmGuestProperties
 * @param hw
 */
void MachineConfigFile::readGuestProperties(const xml::ElementNode &elmGuestProperties,
                                            Hardware &hw)
{
    xml::NodesLoop nl1(elmGuestProperties, "GuestProperty");
    const xml::ElementNode *pelmProp;
    while ((pelmProp = nl1.forAllNodes()))
    {
        GuestProperty prop;

        pelmProp->getAttributeValue("name", prop.strName);
        pelmProp->getAttributeValue("value", prop.strValue);

        pelmProp->getAttributeValue("timestamp", prop.timestamp);
        pelmProp->getAttributeValue("flags", prop.strFlags);

        /* Check guest property 'name' and 'value' for correctness before
         * placing it to local cache. */

        int rc = GuestPropValidateName(prop.strName.c_str(), prop.strName.length() + 1  /* '\0' */);
        if (RT_FAILURE(rc))
        {
            LogRel(("WARNING: Guest property with invalid name (%s) present in VM configuration file. Guest property will be dropped.\n",
                    prop.strName.c_str()));
            continue;
        }

        rc = GuestPropValidateValue(prop.strValue.c_str(), prop.strValue.length() + 1  /* '\0' */);
        if (rc == VERR_TOO_MUCH_DATA)
        {
            LogRel(("WARNING: Guest property '%s' present in VM configuration file and has too long value. Guest property value will be truncated.\n",
                    prop.strName.c_str()));

            /* In order to pass validation, guest property value length (including '\0') in bytes
             * should be less than GUEST_PROP_MAX_VALUE_LEN. Chop it down to an appropriate length. */
            prop.strValue.truncate(GUEST_PROP_MAX_VALUE_LEN - 1 /*terminator*/);
        }
        else if (RT_FAILURE(rc))
        {
            LogRel(("WARNING: Guest property '%s' present in VM configuration file and has invalid value. Guest property will be dropped.\n",
                    prop.strName.c_str()));
            continue;
        }

        hw.llGuestProperties.push_back(prop);
    }
}

/**
 * Helper function to read attributes that are common to \<SATAController\> (pre-1.7)
 * and \<StorageController\>.
 * @param elmStorageController
 * @param sctl
 */
void MachineConfigFile::readStorageControllerAttributes(const xml::ElementNode &elmStorageController,
                                                        StorageController &sctl)
{
    elmStorageController.getAttributeValue("PortCount", sctl.ulPortCount);
    elmStorageController.getAttributeValue("useHostIOCache", sctl.fUseHostIOCache);
}

/**
 * Reads in a \<Hardware\> block and stores it in the given structure. Used
 * both directly from readMachine and from readSnapshot, since snapshots
 * have their own hardware sections.
 *
 * For legacy pre-1.7 settings we also need a storage structure because
 * the IDE and SATA controllers used to be defined under \<Hardware\>.
 *
 * @param elmHardware           Hardware node to read from.
 * @param hw                    Where to store the hardware settings.
 */
void MachineConfigFile::readHardware(const xml::ElementNode &elmHardware,
                                     Hardware &hw)
{
    if (m->sv >= SettingsVersion_v1_16)
    {
        /* Starting with VirtualBox 5.1 the default is Default, before it was
         * Legacy. This needs to matched by areParavirtDefaultSettings(). */
        hw.paravirtProvider = ParavirtProvider_Default;
        /* The new default is disabled, before it was enabled by default. */
        hw.vrdeSettings.fEnabled = false;
        /* The new default is disabled, before it was enabled by default. */
        hw.audioAdapter.fEnabled = false;
    }

    if (m->sv >= SettingsVersion_v1_17)
    {
        /* Starting with VirtualBox 5.2 the default is disabled, before it was
         * enabled. This needs to matched by AudioAdapter::areDefaultSettings(). */
        hw.audioAdapter.fEnabledIn = false;
        /* The new default is disabled, before it was enabled by default. */
        hw.audioAdapter.fEnabledOut = false;
    }

    if (!elmHardware.getAttributeValue("version", hw.strVersion))
    {
        /* KLUDGE ALERT!  For a while during the 3.1 development this was not
           written because it was thought to have a default value of "2".  For
           sv <= 1.3 it defaults to "1" because the attribute didn't exist,
           while for 1.4+ it is sort of mandatory.  Now, the buggy XML writer
           code only wrote 1.7 and later.  So, if it's a 1.7+ XML file and it's
           missing the hardware version, then it probably should be "2" instead
           of "1". */
        if (m->sv < SettingsVersion_v1_7)
            hw.strVersion = "1";
        else
            hw.strVersion = "2";
    }
    Utf8Str strUUID;
    if (elmHardware.getAttributeValue("uuid", strUUID))
        parseUUID(hw.uuid, strUUID, &elmHardware);

    xml::NodesLoop nl1(elmHardware);
    const xml::ElementNode *pelmHwChild;
    while ((pelmHwChild = nl1.forAllNodes()))
    {
        if (pelmHwChild->nameEquals("CPU"))
        {
            if (!pelmHwChild->getAttributeValue("count", hw.cCPUs))
            {
                // pre-1.5 variant; not sure if this actually exists in the wild anywhere
                const xml::ElementNode *pelmCPUChild;
                if ((pelmCPUChild = pelmHwChild->findChildElement("CPUCount")))
                    pelmCPUChild->getAttributeValue("count", hw.cCPUs);
            }

            pelmHwChild->getAttributeValue("hotplug", hw.fCpuHotPlug);
            pelmHwChild->getAttributeValue("executionCap", hw.ulCpuExecutionCap);

            const xml::ElementNode *pelmCPUChild;
            if (hw.fCpuHotPlug)
            {
                if ((pelmCPUChild = pelmHwChild->findChildElement("CpuTree")))
                    readCpuTree(*pelmCPUChild, hw.llCpus);
            }

            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtEx")))
            {
                pelmCPUChild->getAttributeValue("enabled", hw.fHardwareVirt);
            }
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExNestedPaging")))
                pelmCPUChild->getAttributeValue("enabled", hw.fNestedPaging);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExLargePages")))
                pelmCPUChild->getAttributeValue("enabled", hw.fLargePages);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExVPID")))
                pelmCPUChild->getAttributeValue("enabled", hw.fVPID);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExUX")))
                pelmCPUChild->getAttributeValue("enabled", hw.fUnrestrictedExecution);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtForce")))
                pelmCPUChild->getAttributeValue("enabled", hw.fHardwareVirtForce);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExUseNativeApi")))
                pelmCPUChild->getAttributeValue("enabled", hw.fUseNativeApi);
            if ((pelmCPUChild = pelmHwChild->findChildElement("HardwareVirtExVirtVmsaveVmload")))
                pelmCPUChild->getAttributeValue("enabled", hw.fVirtVmsaveVmload);

            if (!(pelmCPUChild = pelmHwChild->findChildElement("PAE")))
            {
                /* The default for pre 3.1 was false, so we must respect that. */
                if (m->sv < SettingsVersion_v1_9)
                    hw.fPAE = false;
            }
            else
                pelmCPUChild->getAttributeValue("enabled", hw.fPAE);

            bool fLongMode;
            if (   (pelmCPUChild = pelmHwChild->findChildElement("LongMode"))
                && pelmCPUChild->getAttributeValue("enabled", fLongMode) )
                hw.enmLongMode = fLongMode ? Hardware::LongMode_Enabled : Hardware::LongMode_Disabled;
            else
                hw.enmLongMode = Hardware::LongMode_Legacy;

            if ((pelmCPUChild = pelmHwChild->findChildElement("SyntheticCpu")))
            {
                bool fSyntheticCpu = false;
                pelmCPUChild->getAttributeValue("enabled", fSyntheticCpu);
                hw.uCpuIdPortabilityLevel = fSyntheticCpu ? 1 : 0;
            }
            pelmHwChild->getAttributeValue("CpuIdPortabilityLevel", hw.uCpuIdPortabilityLevel);
            pelmHwChild->getAttributeValue("CpuProfile", hw.strCpuProfile);

            if ((pelmCPUChild = pelmHwChild->findChildElement("TripleFaultReset")))
                pelmCPUChild->getAttributeValue("enabled", hw.fTripleFaultReset);

            if ((pelmCPUChild = pelmHwChild->findChildElement("APIC")))
                pelmCPUChild->getAttributeValue("enabled", hw.fAPIC);
            if ((pelmCPUChild = pelmHwChild->findChildElement("X2APIC")))
                pelmCPUChild->getAttributeValue("enabled", hw.fX2APIC);
            if (hw.fX2APIC)
                hw.fAPIC = true;
            pelmCPUChild = pelmHwChild->findChildElement("IBPBOn");
            if (pelmCPUChild)
            {
                pelmCPUChild->getAttributeValue("vmexit", hw.fIBPBOnVMExit);
                pelmCPUChild->getAttributeValue("vmentry", hw.fIBPBOnVMEntry);
            }
            pelmCPUChild = pelmHwChild->findChildElement("SpecCtrl");
            if (pelmCPUChild)
                pelmCPUChild->getAttributeValue("enabled", hw.fSpecCtrl);
            pelmCPUChild = pelmHwChild->findChildElement("SpecCtrlByHost");
            if (pelmCPUChild)
</