<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
<book>
<bookinfo>
<title>$VBOX_PRODUCT<superscript>®</superscript></title>
<subtitle>Programming Guide and Reference</subtitle>
<edition>Version $VBOX_VERSION_STRING</edition>
<corpauthor>$VBOX_VENDOR</corpauthor>
<copyright>
<year>2004-$VBOX_C_YEAR</year>
<holder>$VBOX_VENDOR</holder>
</copyright>
</bookinfo>
<chapter>
<title>Introduction</title>
<para>VirtualBox comes with comprehensive support for third-party
developers. This Software Development Kit (SDK) contains all the
documentation and interface files that are needed to write code that
interacts with VirtualBox.</para>
<sect1>
<title>Modularity: the building blocks of VirtualBox</title>
<para>VirtualBox is cleanly separated into several layers, which can be
visualized like in the picture below:</para>
<mediaobject>
<imageobject>
width="12cm" />
</imageobject>
</mediaobject>
<para>The orange area represents code that runs in kernel mode, the blue
area represents userspace code.</para>
<para>At the bottom of the stack resides the hypervisor -- the core of
the virtualization engine, controlling execution of the virtual machines
and making sure they do not conflict with each other or whatever the
host computer is doing otherwise.</para>
<para>On top of the hypervisor, additional internal modules provide
extra functionality. For example, the RDP server, which can deliver the
graphical output of a VM remotely to an RDP client, is a separate module
that is only loosely tacked into the virtual graphics device. Live
Migration and Resource Monitor are additional modules currently in the
process of being added to VirtualBox.</para>
<para>What is primarily of interest for purposes of the SDK is the API
layer block that sits on top of all the previously mentioned blocks.
This API, which we call the <emphasis role="bold">"Main API"</emphasis>,
exposes the entire feature set of the virtualization engine below. It is
completely documented in this SDK Reference -- see <xref
linkend="sdkref_classes" /> and <xref linkend="sdkref_enums" /> -- and
available to anyone who wishes to control VirtualBox programmatically.
We chose the name "Main API" to differentiate it from other programming
interfaces of VirtualBox that may be publicly accessible.</para>
<para>With the Main API, you can create, configure, start, stop and
delete virtual machines, retrieve performance statistics about running
VMs, configure the VirtualBox installation in general, and more. In
fact, internally, the front-end programs
<computeroutput>VirtualBox</computeroutput> and
<computeroutput>VBoxManage</computeroutput> use nothing but this API as
well -- there are no hidden backdoors into the virtualization engine for
our own front-ends. This ensures the entire Main API is both
well-documented and well-tested. (The same applies to
<computeroutput>VBoxHeadless</computeroutput>, which is not shown in the
image.)</para>
</sect1>
<sect1 id="webservice-or-com">
<title>Two guises of the same "Main API": the web service or
<para>There are several ways in which the Main API can be called by
other code:<orderedlist>
<listitem>
<para>VirtualBox comes with a <emphasis role="bold">web
service</emphasis> that maps nearly the entire Main API. The web
service ships in a stand-alone executable
(<computeroutput>vboxwebsrv</computeroutput>) that, when running,
acts as an HTTP server, accepts SOAP connections and processes
them.</para>
<para>Since the entire web service API is publicly described in a
web service description file (in WSDL format), you can write
client programs that call the web service in any language with a
toolkit that understands WSDL. These days, that includes most
programming languages that are available: Java, C++, .NET, PHP,
Python, Perl and probably many more.</para>
<para>All of this is explained in detail in subsequent chapters of
this book.</para>
<para>There are two ways in which you can write client code that
uses the web service:<orderedlist>
<listitem>
<para>For Java as well as Python, the SDK contains
easy-to-use classes that allow you to use the web service in
an object-oriented, straightforward manner. We shall refer
to this as the <emphasis role="bold">"object-oriented web
service (OOWS)"</emphasis>.</para>
<para>The OO bindings for Java are described in <xref
linkend="javaapi" />, those for Python in <xref lang=""
linkend="glue-python-ws" />.</para>
</listitem>
<listitem>
<para>Alternatively, you can use the web service directly,
without the object-oriented client layer. We shall refer to
this as the <emphasis role="bold">"raw web
service"</emphasis>.</para>
<para>You will then have neither native object orientation
nor full type safety, since web services are neither
object-oriented nor stateful. However, in this way, you can
write client code even in languages for which we do not ship
object-oriented client code; all you need is a programming
language with a toolkit that can parse WSDL and generate
client wrapper code from it.</para>
<para>We describe this further in <xref
linkend="raw-webservice" />, with samples for Java and
Perl.</para>
</listitem>
</orderedlist></para>
</listitem>
<listitem>
<para>Internally, for portability and easier maintenance, the Main
API is implemented using the <emphasis role="bold">Component
Object Model (COM),</emphasis> an interprocess mechanism for
software components originally introduced by Microsoft for
Microsoft Windows. On a Windows host, VirtualBox will use
Microsoft COM; on other hosts where COM is not present, it ships
with XPCOM, a free software implementation of COM originally
created by the Mozilla project for their browsers.</para>
<para>So, if you are familiar with COM and the C++ programming
language (or with any other programming language that can handle
necessary files and documentation to build fully functional COM
applications. For an introduction, please see <xref
linkend="api_com" /> below.</para>
<para>The VirtualBox front-ends (the graphical user interfaces as
well as the command line), which are all written in C++, use
another front-end to this COM API, mapping almost all of it to
SOAP clients.</para>
</listitem>
</orderedlist></para>
<para>If you wonder which way to choose, here are a few
comparisons:<table>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Web service</emphasis></entry>
</row>
<row>
<entry><emphasis role="bold">Pro:</emphasis> Easy to use with
Java and Python with the object-oriented web service;
extensive support even with other languages (C++, .NET, PHP,
Perl and others)</entry>
<entry><emphasis role="bold">Con:</emphasis> Usable from
languages where COM bridge available (most languages on
Windows platform, Python and C++ on other hosts)</entry>
</row>
<row>
<entry><emphasis role="bold">Pro:</emphasis> Client can be on
remote machine</entry>
<entry><emphasis role="bold">Con: </emphasis>Client must be on
the same host where virtual machine is executed</entry>
</row>
<row>
<entry><emphasis role="bold">Con: </emphasis>Significant
overhead due to XML marshalling over the wire for each method
call</entry>
<entry><emphasis role="bold">Pro: </emphasis>Relatively low
invocation overhead</entry>
</row>
</tbody>
</tgroup>
</table></para>
<para>In the following chapters, we will describe the different ways in
which to program VirtualBox, starting with the method that is easiest to
use and then increase complexity as we go along.</para>
</sect1>
<sect1 id="api_soap_intro">
<title>About web services in general</title>
<para>Web services are a particular type of programming interface.
Whereas, with "normal" programming, a program calls an application
programming interface (API) defined by another program or the operating
system and both sides of the interface have to agree on the calling
convention and, in most cases, use the same programming language, web
services use Internet standards such as HTTP and XML to
communicate.<footnote>
<para>In some ways, web services promise to deliver the same thing
as CORBA and DCOM did years ago. However, while these previous
technologies relied on specific binary protocols and thus proved to
be difficult to use between diverging platforms, web services
circumvent these incompatibilities by using text-only standards like
HTTP and XML. On the downside (and, one could say, typical of things
related to XML), a lot of standards are involved before a web
service can be implemented. Many of the standards invented around
XML are used one way or another. As a result, web services are slow
and verbose, and the details can be incredibly messy. The relevant
standards here are called SOAP and WSDL, where SOAP describes the
format of the messages that are exchanged (an XML document wrapped
in an HTTP header), and WSDL is an XML format that describes a
complete API provided by a web service. WSDL in turn uses XML Schema
to describe types, which is not exactly terse either. However, as
you will see from the samples provided in this chapter, the
VirtualBox web service shields you from these details and is easy to
use.</para>
</footnote></para>
<para>In order to successfully use a web service, a number of things are
required -- primarily, a web service accepting connections; service
descriptions; and then a client that connects to that web service. The
connections are governed by the SOAP standard, which describes how
messages are to be exchanged between a service and its clients; the
service descriptions are governed by WSDL.</para>
<para>In the case of VirtualBox, this translates into the following
three components:<orderedlist>
<listitem>
<para>The VirtualBox web service (the "server"): this is the
<computeroutput>vboxwebsrv</computeroutput> executable shipped
with VirtualBox. Once you start this executable (which acts as a
web service and thus control a VirtualBox installation.</para>
</listitem>
<listitem>
<para>VirtualBox also comes with WSDL files that describe the
services provided by the web service. You can find these files in
directory. These files are understood by the web service toolkits
that are shipped with most programming languages and enable you to
easily access a web service even if you don't use our
object-oriented client layers. VirtualBox is shipped with
pregenerated web service glue code for several languages (Python,
Perl, Java).</para>
</listitem>
<listitem>
<para>A client that connects to the web service in order to
control the VirtualBox installation.</para>
<para>Unless you play with some of the samples shipped with
VirtualBox, this needs to be written by you.</para>
</listitem>
</orderedlist></para>
</sect1>
<sect1 id="runvboxwebsrv">
<title>Running the web service</title>
<para>The web service ships in an stand-alone executable,
<computeroutput>vboxwebsrv</computeroutput>, that, when running, acts as
a HTTP server, accepts SOAP connections and processes them -- remotely
or from the same machine.<note>
<para>The web service executable is not contained with the
VirtualBox SDK, but instead ships with the standard VirtualBox
binary package for your specific platform. Since the SDK contains
only platform-independent text files and documentation, the binaries
are instead shipped with the platform-specific packages. For this
reason the information how to run it as a service is included in the
VirtualBox documentation.</para>
</note></para>
<para>The <computeroutput>vboxwebsrv</computeroutput> program, which
implements the web service, is a text-mode (console) program which,
after being started, simply runs until it is interrupted with Ctrl-C or
a kill command.</para>
<para>Once the web service is started, it acts as a front-end to the
VirtualBox installation of the user account that it is running under. In
other words, if the web service is run under the user account of
<computeroutput>user1</computeroutput>, it will see and manipulate the
virtual machines and other data represented by the VirtualBox data of
that user (for example, on a Linux machine, under
VirtualBox User Manual for details on where this data is stored).</para>
<sect2 id="vboxwebsrv-ref">
<title>Command line options of vboxwebsrv</title>
<para>The web service supports the following command line
options:</para>
<itemizedlist>
<listitem>
<para><computeroutput>--help</computeroutput> (or
<computeroutput>-h</computeroutput>): print a brief summary of
command line options.</para>
</listitem>
<listitem>
<para><computeroutput>--background</computeroutput> (or
<computeroutput>-b</computeroutput>): run the web service as a
background daemon. This option is not supported on Windows
hosts.</para>
</listitem>
<listitem>
<para><computeroutput>--host</computeroutput> (or
<computeroutput>-H</computeroutput>): This specifies the host to
bind to and defaults to "localhost".</para>
</listitem>
<listitem>
<para><computeroutput>--port</computeroutput> (or
<computeroutput>-p</computeroutput>): This specifies which port to
bind to on the host and defaults to 18083.</para>
</listitem>
<listitem>
<para><computeroutput>--ssl</computeroutput> (or
<computeroutput>-s</computeroutput>): This enables SSL support.</para>
</listitem>
<listitem>
<para><computeroutput>--keyfile</computeroutput> (or
<computeroutput>-K</computeroutput>): This specifies the file name
containing the server private key and the certificate. This is a
mandatory parameter if SSL is enabled.</para>
</listitem>
<listitem>
<para><computeroutput>--passwordfile</computeroutput> (or
<computeroutput>-a</computeroutput>): This specifies the file name
containing the password for the server private key. If unspecified
or an empty string is specified this is interpreted as an empty
password (i.e. the private key is not protected by a password). If
the file name <computeroutput>-</computeroutput> is specified then
then the password is read from the standard input stream, otherwise
from the specified file. The user is responsible for appropriate
access rights to protect the confidential password.</para>
</listitem>
<listitem>
<para><computeroutput>--cacert</computeroutput> (or
<computeroutput>-c</computeroutput>): This specifies the file name
containing the CA certificate appropriate for the server
certificate.</para>
</listitem>
<listitem>
<para><computeroutput>--capath</computeroutput> (or
<computeroutput>-C</computeroutput>): This specifies the directory
containing several CA certificates appropriate for the server
certificate.</para>
</listitem>
<listitem>
<para><computeroutput>--dhfile</computeroutput> (or
<computeroutput>-D</computeroutput>): This specifies the file name
containing the DH key. Alternatively it can contain the number of
bits of the DH key to generate. If left empty, RSA is used.</para>
</listitem>
<listitem>
<para><computeroutput>--randfile</computeroutput> (or
<computeroutput>-r</computeroutput>): This specifies the file name
containing the seed for the random number generator. If left empty,
an operating system specific source of the seed.</para>
</listitem>
<listitem>
<para><computeroutput>--timeout</computeroutput> (or
<computeroutput>-t</computeroutput>): This specifies the session
timeout, in seconds, and defaults to 300 (five minutes). A web
service client that has logged on but makes no calls to the web
service will automatically be disconnected after the number of
seconds specified here, as if it had called the
<computeroutput>IWebSessionManager::logoff()</computeroutput>
method provided by the web service itself.</para>
<para>It is normally vital that each web service client call this
method, as the web service can accumulate large amounts of memory
when running, especially if a web service client does not properly
release managed object references. As a result, this timeout value
should not be set too high, especially on machines with a high
load on the web service, or the web service may eventually deny
service.</para>
</listitem>
<listitem>
<para><computeroutput>--check-interval</computeroutput> (or
<computeroutput>-i</computeroutput>): This specifies the interval
in which the web service checks for timed-out clients, in seconds,
and defaults to 5. This normally does not need to be
changed.</para>
</listitem>
<listitem>
<para><computeroutput>--threads</computeroutput> (or
<computeroutput>-T</computeroutput>): This specifies the maximum
number or worker threads, and defaults to 100. This normally does
not need to be changed.</para>
</listitem>
<listitem>
<para><computeroutput>--keepalive</computeroutput> (or
<computeroutput>-k</computeroutput>): This specifies the maximum
number of requests which can be sent in one web service connection,
and defaults to 100. This normally does not need to be changed.</para>
</listitem>
<listitem>
<para><computeroutput>--authentication</computeroutput> (or
<computeroutput>-A</computeroutput>): This specifies the desired
web service authentication method. If the parameter is not
specified or the empty string is specified it does not change the
authentication method, otherwise it is set to the specified value.
Using this parameter is a good measure against accidental
misconfiguration, as the web service ensures periodically that it
isn't changed.</para>
</listitem>
<listitem>
<para><computeroutput>--verbose</computeroutput> (or
<computeroutput>-v</computeroutput>): Normally, the web service
outputs only brief messages to the console each time a request is
served. With this option, the web service prints much more detailed
data about every request and the COM methods that those requests
are mapped to internally, which can be useful for debugging client
programs.</para>
</listitem>
<listitem>
<para><computeroutput>--pidfile</computeroutput> (or
<computeroutput>-P</computeroutput>): Name of the PID file which is
created when the daemon was started.</para>
</listitem>
<listitem>
<para><computeroutput>--logfile</computeroutput> (or
<computeroutput>-F</computeroutput>)
<computeroutput><file></computeroutput>: If this is
specified, the web service not only prints its output to the
console, but also writes it to the specified file. The file is
created if it does not exist; if it does exist, new output is
appended to it. This is useful if you run the web service
unattended and need to debug problems after they have
occurred.</para>
</listitem>
<listitem>
<para><computeroutput>--logrotate</computeroutput> (or
<computeroutput>-R</computeroutput>): Number of old log files to
keep, defaults to 10. Log rotation is disabled if set to 0.</para>
</listitem>
<listitem>
<para><computeroutput>--logsize</computeroutput> (or
<computeroutput>-S</computeroutput>): Maximum size of log file in
bytes, defaults to 100MB. Log rotation is triggered if the file
grows beyond this limit.</para>
</listitem>
<listitem>
<para><computeroutput>--loginterval</computeroutput> (or
<computeroutput>-I</computeroutput>): Maximum time interval to be
put in a log file before rotation is triggered, in seconds, and
defaults to one day.</para>
</listitem>
</itemizedlist>
</sect2>
<sect2 id="websrv_authenticate">
<title>Authenticating at web service logon</title>
that wants to use the web service must first log on by calling the
<computeroutput>IWebsessionManager::logon()</computeroutput> API (see
<xref linkend="IWebsessionManager__logon" />) that is specific to the
web service. Logon is necessary for the web service to be stateful;
internally, it maintains a session for each client that connects to
it.</para>
<para>The <computeroutput>IWebsessionManager::logon()</computeroutput>
API takes a user name and a password as arguments, which the web
service then passes to a customizable authentication plugin that
performs the actual authentication.</para>
<para>For testing purposes, it is recommended that you first disable
authentication with this command:<screen>VBoxManage setproperty websrvauthlibrary null</screen></para>
<para><warning>
<para>This will cause all logons to succeed, regardless of user
name or password. This should of course not be used in a
production environment.</para>
</warning>Generally, the mechanism by which clients are
authenticated is configurable by way of the
<computeroutput>VBoxManage</computeroutput> command:</para>
<para><screen>VBoxManage setproperty websrvauthlibrary default|null|<library></screen></para>
that conforms with the specifications for VirtualBox external
authentication modules as laid out in section <emphasis
role="bold">VRDE authentication</emphasis> of the VirtualBox User
Manual; the web service uses the same kind of modules as the
VirtualBox VRDE server. For technical details on VirtualBox external
authentication modules see <xref linkend="vbox-auth" /></para>
<para>By default, after installation, the web service uses the
VBoxAuth module that ships with VirtualBox. This module uses PAM on
combination is accepted, it does not have to be the username and
password of the user running the web service daemon. Unless
<computeroutput>vboxwebsrv</computeroutput> runs as root, PAM
authentication can fail, because sometimes the file
not readable. On most Linux distribution PAM uses a suid root helper
internally, so make sure you test this before deploying it. One can
override this behavior by setting the environment variable
<computeroutput>VBOX_PAM_ALLOW_INACTIVE</computeroutput> which will
suppress failures when unable to read the shadow password file. Please
use this variable carefully, and only if you fully understand what
you're doing.</para>
</sect2>
</sect1>
</chapter>
<chapter>
<title>Environment-specific notes</title>
<para>The Main API described in <xref linkend="sdkref_classes" /> and
<xref linkend="sdkref_enums" /> is mostly identical in all the supported
programming environments which have been briefly mentioned in the
introduction of this book. As a result, the Main API's general concepts
described in <xref linkend="concepts" /> are the same whether you use the
object-oriented web service (OOWS) for JAX-WS or a raw web service
connection via, say, Perl, or whether you use C++ COM bindings.</para>
<para>Some things are different depending on your environment, however.
These differences are explained in this chapter.</para>
<sect1 id="glue">
<title>Using the object-oriented web service (OOWS)</title>
<para>As explained in <xref linkend="webservice-or-com" />, VirtualBox
ships with client-side libraries for Java, Python and PHP that allow you
to use the VirtualBox web service in an intuitive, object-oriented way.
These libraries shield you from the client-side complications of managed
object references and other implementation details that come with the
VirtualBox web service. (If you are interested in these complications,
have a look at <xref linkend="raw-webservice" />).</para>
<para>We recommend that you start your experiments with the VirtualBox
web service by using our object-oriented client libraries for JAX-WS, a
web service toolkit for Java, which enables you to write code to
interact with VirtualBox in the simplest manner possible.</para>
<para>As "interfaces", "attributes" and "methods" are COM concepts,
please read the documentation in <xref linkend="sdkref_classes" /> and
<xref linkend="sdkref_enums" /> with the following notes in mind.</para>
<para>The OOWS bindings attempt to map the Main API as closely as
possible to the Java, Python and PHP languages. In other words, objects
are objects, interfaces become classes, and you can call methods on
objects as you would on local objects.</para>
<para>The main difference remains with attributes: to read an attribute,
call a "getXXX" method, with "XXX" being the attribute name with a
capitalized first letter. So when the Main API Reference says that
<computeroutput>IMachine</computeroutput> has a "name" attribute (see
<xref linkend="IMachine__name" xreflabel="IMachine::name" />), call
<computeroutput>getName()</computeroutput> on an IMachine object to
obtain a machine's name. Unless the attribute is marked as read-only in
the documentation, there will also be a corresponding "set"
method.</para>
<sect2 id="glue-jax-ws">
<title>The object-oriented web service for JAX-WS</title>
<para>JAX-WS is a powerful toolkit by Sun Microsystems to build both
server and client code with Java. It is part of Java 6 (JDK 1.6), but
can also be obtained separately for Java 5 (JDK 1.5). The VirtualBox
SDK comes with precompiled OOWS bindings working with both Java 5 and
6.</para>
<para>The following sections explain how to get the JAX-WS sample code
running and explain a few common practices when using the JAX-WS
object-oriented web service.</para>
<sect3>
<title>Preparations</title>
<para>Since JAX-WS is already integrated into Java 6, no additional
preparations are needed for Java 6.</para>
<para>If you are using Java 5 (JDK 1.5.x), you will first need to
download and install an external JAX-WS implementation, as Java 5
does not support JAX-WS out of the box; for example, you can
download one from here: <ulink
url="https://jax-ws.dev.java.net/2.1.4/JAXWS2.1.4-20080502.jar">https://jax-ws.dev.java.net/2.1.4/JAXWS2.1.4-20080502.jar</ulink>.
Then perform the installation (<computeroutput>java -jar
</sect3>
<sect3>
<title>Getting started: running the sample code</title>
<para>To run the OOWS for JAX-WS samples that we ship with the SDK,
perform the following steps: <orderedlist>
<listitem>
<para>Open a terminal and change to the directory where the
JAX-WS samples reside.<footnote>
<para>In
</footnote> Examine the header of
<computeroutput>Makefile</computeroutput> to see if the
supplied variables (Java compiler, Java executable) and a few
other details match your system settings.</para>
</listitem>
<listitem>
<para>To start the VirtualBox web service, open a second
terminal and change to the directory where the VirtualBox
<para>The web service now waits for connections and will run
until you press Ctrl+C in this second terminal. The -v
argument causes it to log all connections to the terminal.
(See <xref linkend="runvboxwebsrv" os="" /> for details on how
to run the web service.)</para>
</listitem>
<listitem>
<para>Back in the first terminal and still in the samples
directory, to start a simple client example just type:<screen>make run16</screen></para>
<para>if you're on a Java 6 system; on a Java 5 system, run
<computeroutput>make run15</computeroutput> instead.</para>
<para>This should work on all Unix-like systems such as Linux
and Solaris. For Windows systems, use commands similar to what
is used in the Makefile.</para>
<para>This will compile the
first call and then execute the resulting
<computeroutput>clienttest</computeroutput> class to show the
locally installed VMs (see below).</para>
</listitem>
</orderedlist></para>
<para>The <computeroutput>clienttest</computeroutput> sample
imitates a few typical command line tasks that
<computeroutput>VBoxManage</computeroutput>, VirtualBox's regular
command-line front-end, would provide (see the VirtualBox User
Manual for details). In particular, you can run:<itemizedlist>
<listitem>
<para><computeroutput>java clienttest show
vms</computeroutput>: show the virtual machines that are
registered locally.</para>
</listitem>
<listitem>
<para><computeroutput>java clienttest list
hostinfo</computeroutput>: show various information about the
host this VirtualBox installation runs on.</para>
</listitem>
<listitem>
<para><computeroutput>java clienttest startvm
<vmname|uuid></computeroutput>: start the given virtual
machine.</para>
</listitem>
</itemizedlist></para>
code illustrates common basic practices how to use the VirtualBox
OOWS for JAX-WS, which we will explain in more detail in the
following chapters.</para>
</sect3>
<sect3>
<title>Logging on to the web service</title>
<para>Before a web service client can do anything useful, two
objects need to be created, as can be seen in the
<computeroutput>clienttest</computeroutput> constructor:<orderedlist>
<listitem>
<para>An instance of <xref linkend="IWebsessionManager"
xreflabel="IWebsessionManager" />, which is an interface
provided by the web service to manage "web sessions" -- that
is, stateful connections to the web service with persistent
objects upon which methods can be invoked.</para>
<para>In the OOWS for JAX-WS, the IWebsessionManager class
must be constructed explicitly, and a URL must be provided in
the constructor that specifies where the web service (the
server) awaits connections. The code in
"http://localhost:18083/", which is the default.</para>
<para>The port number, by default 18083, must match the port
number given to the
<computeroutput>vboxwebsrv</computeroutput> command line; see
<xref linkend="vboxwebsrv-ref" />.</para>
</listitem>
<listitem>
<para>After that, the code calls <xref
linkend="IWebsessionManager__logon"
xreflabel="IWebsessionManager::logon()" />, which is the first
call that actually communicates with the server. This
authenticates the client with the web service and returns an
instance of <xref linkend="IVirtualBox"
xreflabel="IVirtualBox" />, the most fundamental interface of
the VirtualBox web service, from which all other functionality
can be derived.</para>
<para>If logon doesn't work, please take another look at <xref
linkend="websrv_authenticate" />.</para>
</listitem>
</orderedlist></para>
</sect3>
<sect3>
<title>Object management</title>
<para>The current OOWS for JAX-WS has certain memory management
related limitations. When you no longer need an object, call its
<xref linkend="IManagedObjectRef__release"
xreflabel="IManagedObjectRef::release()" /> method explicitly, which
frees appropriate managed reference, as is required by the raw
web service; see <xref linkend="managed-object-references" /> for
details. This limitation may be reconsidered in a future version of
the VirtualBox SDK.</para>
</sect3>
</sect2>
<sect2 id="glue-python-ws">
<title>The object-oriented web service for Python</title>
<para>VirtualBox comes with two flavors of a Python API: one for web
<xref linkend="pycom" />. The client code is mostly similar, except
for the initialization part, so it is up to the application developer
to choose the appropriate technology. Moreover, a common Python glue
layer exists, abstracting out concrete platform access details, see
<xref linkend="glue-python" />.</para>
<para>As indicated in <xref linkend="webservice-or-com" />, the
does not require a web server to be running. On the other hand, the
installation (VirtualBox ships the most important ones for each
platform<footnote>
<para>On On Mac OS X only the Python versions bundled with the OS
are officially supported. This means Python 2.3 for 10.4, Python
2.5 for 10.5 and Python 2.5 and 2.6 for 10.6.</para>
</footnote>). On Windows, you can use the Main API from Python if the Win32 extensions
package for Python<footnote>
<para>See <ulink
url="http://sourceforge.net/project/showfiles.php?group_id=78018">http://sourceforge.net/project/showfiles.php?group_id=78018</ulink>.</para>
</footnote> is installed. Version of Python Win32 extensions earlier than 2.16 are known to have bugs,
leading to issues with VirtualBox Python bindings, and also some early builds of Python 2.5 for Windows have issues with
reporting platform name on some Windows versions, so please make sure to use latest available Python
and Win32 extensions.</para>
<para>The VirtualBox OOWS for Python relies on the Python ZSI SOAP
implementation (see <ulink
which you will need to install locally before trying the examples.
Most Linux distributions come with package for ZSI, such as
<computeroutput>python-zsi</computeroutput> in Ubuntu.</para>
<para>To get started, open a terminal and change to the
directory, which contains an example of a simple interactive shell
able to control a VirtualBox instance. The shell is written using the
API layer, thereby hiding different implementation details, so it is
actually an example of code share among XPCOM, MSCOM and web services.
If you are interested in how to interact with the web services layer
directly, have a look at
contains the glue layer for all target platforms (i.e. XPCOM, MSCOM
and web services).</para>
# start web service with object autocollection disabled
export VBOX_PROGRAM_PATH=/opt/VirtualBox
# your VirtualBox installation directory
# where you've extracted the SDK
details on the shell's functionality. For you, as a VirtualBox
application developer, the vboxshell sample could be interesting as an
example of how to write code targeting both local and remote cases
only difference is how it interacts with the invocation layer. You can
use the <computeroutput>connect</computeroutput> shell command to
connect to remote VirtualBox servers; in this case you can skip
starting the local web server.</para>
</sect2>
<sect2>
<title>The object-oriented web service for PHP</title>
<para>VirtualBox also comes with object-oriented web service (OOWS)
wrappers for PHP5. These wrappers rely on the PHP SOAP
Extension<footnote>
</footnote>, which can be installed by configuring PHP with
<computeroutput>--enable-soap</computeroutput>.</para>
</sect2>
</sect1>
<sect1 id="raw-webservice">
<title>Using the raw web service with any language</title>
<para>The following examples show you how to use the raw web service,
without the object-oriented client-side code that was described in the
previous chapter.</para>
<para>Generally, when reading the documentation in <xref
linkend="sdkref_classes" /> and <xref linkend="sdkref_enums" />, due to
the limitations of SOAP and WSDL lined out in <xref
linkend="rawws-conventions" />, please have the following notes in
mind:</para>
<para><orderedlist>
<listitem>
<para>Any COM method call becomes a <emphasis role="bold">plain
function call</emphasis> in the raw web service, with the object
as an additional first parameter (before the "real" parameters
listed in the documentation). So when the documentation says that
the <computeroutput>IVirtualBox</computeroutput> interface
supports the <computeroutput>createMachine()</computeroutput>
method (see <xref linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine()" />), the web service
operation is
<computeroutput>IVirtualBox_createMachine(...)</computeroutput>,
and a managed object reference to an
<computeroutput>IVirtualBox</computeroutput> object must be passed
as the first argument.</para>
</listitem>
<listitem>
<para>For <emphasis role="bold">attributes</emphasis> in
interfaces, there will be at least one "get" function; there will
also be a "set" function, unless the attribute is "readonly". The
attribute name will be appended to the "get" or "set" prefix, with
a capitalized first letter. So, the "version" readonly attribute
of the <computeroutput>IVirtualBox</computeroutput> interface can
be retrieved by calling
<computeroutput>IVirtualBox_getVersion(vbox)</computeroutput>,
with <computeroutput>vbox</computeroutput> being the VirtualBox
object.</para>
</listitem>
<listitem>
<para>Whenever the API documentation says that a method (or an
attribute getter) returns an <emphasis
role="bold">object</emphasis>, it will returned a managed object
reference in the web service instead. As said above, managed
object references should be released if the web service client
does not log off again immediately!</para>
</listitem>
</orderedlist></para>
<para></para>
<sect2 id="webservice-java-sample">
<title>Raw web service example for Java with Axis</title>
<para>Axis is an older web service toolkit created by the Apache
foundation. If your distribution does not have it installed, you can
get a binary from <ulink
following examples assume that you have Axis 1.4 installed.</para>
<para>The VirtualBox SDK ships with an example for Axis that, again,
imitates a few of the commands of
<computeroutput>VBoxManage</computeroutput> over the wire.</para>
<para>Then perform the following steps:<orderedlist>
<listitem>
<para>Create a working directory somewhere. Under your
VirtualBox installation directory, find the
directory and copy the file
directory.</para>
</listitem>
<listitem>
<para>Open a terminal in your working directory. Execute the
following command:<screen> java org.apache.axis.wsdl.WSDL2Java /path/to/vboxwebService.wsdl</screen></para>
file should be located in the
directory.</para>
<para>If this fails, your Apache Axis may not be located on your
system classpath, and you may have to adjust the CLASSPATH
environment variable. Something like this:<screen>export CLASSPATH="/path-to-axis-1_4/lib/*":$CLASSPATH</screen></para>
<para>Use the directory where the Axis JAR files are located.
Mind the quotes so that your shell passes the "*" character to
the java executable without expanding. Alternatively, add a
corresponding <computeroutput>-classpath</computeroutput>
argument to the "java" call above.</para>
<para>If the command executes successfully, you should see an
"org" directory with subdirectories containing Java source files
in your working directory. These classes represent the
interfaces that the VirtualBox web service offers, as described
by the WSDL file.</para>
<para>This is the bit that makes using web services so
attractive to client developers: if a language's toolkit
understands WSDL, it can generate large amounts of support code
automatically. Clients can then easily use this support code and
can be done with just a few lines of code.</para>
</listitem>
<listitem>
<para>Next, compile the
<computeroutput>clienttest.java</computeroutput> source:<screen>javac clienttest.java </screen></para>
</listitem>
<listitem>
<para>To start the VirtualBox web service, open a second
terminal and change to the directory where the VirtualBox
<para>The web service now waits for connections and will run
until you press Ctrl+C in this second terminal. The -v argument
causes it to log all connections to the terminal. (See <xref
linkend="runvboxwebsrv" os="" /> for details on how to run the
web service.)</para>
</listitem>
<listitem>
<para>Back in the original terminal where you compiled the Java
source, run the resulting binary, which will then connect to the
web service:<screen>java clienttest</screen></para>
<para>The client sample will connect to the web service (on
localhost, but the code could be changed to connect remotely if
the web service was running on a different machine) and make a
number of method calls. It will output the version number of
your VirtualBox installation and a list of all virtual machines
that are currently registered (with a bit of seemingly random
data, which will be explained later).</para>
</listitem>
</orderedlist></para>
</sect2>
<sect2 id="raw-webservice-perl">
<title>Raw web service example for Perl</title>
<para>We also ship a small sample for Perl. It uses the SOAP::Lite
perl module to communicate with the VirtualBox web service.</para>
<para>The
directory contains a pre-generated Perl module that allows for
communicating with the web service from Perl. You can generate such a
module yourself using the "stubmaker" tool that comes with SOAP::Lite,
but since that tool is slow as well as sometimes unreliable, we are
shipping a working module with the SDK for your convenience.</para>
<para>Perform the following steps:<orderedlist>
<listitem>
<para>If SOAP::Lite is not yet installed on your system, you
will need to install the package first. On Debian-based systems,
the package is called
<computeroutput>libsoap-lite-perl</computeroutput>; on Gentoo,
</listitem>
<listitem>
<para>Open a terminal in the
directory.</para>
</listitem>
<listitem>
<para>To start the VirtualBox web service, open a second
terminal and change to the directory where the VirtualBox
<para>The web service now waits for connections and will run
until you press Ctrl+C in this second terminal. The -v argument
causes it to log all connections to the terminal. (See <xref
linkend="runvboxwebsrv" os="" /> for details on how to run the
web service.)</para>
</listitem>
<listitem>
<para>In the first terminal with the Perl sample, run the
</listitem>
</orderedlist></para>
</sect2>
<sect2>
<title>Programming considerations for the raw web service</title>
<para>If you use the raw web service, you need to keep a number of
things in mind, or you will sooner or later run into issues that are
not immediately obvious. By contrast, the object-oriented client-side
libraries described in <xref linkend="glue" /> take care of these
things automatically and thus greatly simplify using the web
service.</para>
<sect3 id="rawws-conventions">
<title>Fundamental conventions</title>
<para>If you are familiar with other web services, you may find the
VirtualBox web service to behave a bit differently to accommodate
for the fact that VirtualBox web service more or less maps the
VirtualBox Main COM API. The following main differences had to be
taken care of:<itemizedlist>
<listitem>
<para>Web services, as expressed by WSDL, are not
object-oriented. Even worse, they are normally stateless (or,
in web services terminology, "loosely coupled"). Web service
operations are entirely procedural, and one cannot normally
make assumptions about the state of a web service between
function calls.</para>
<para>In particular, this normally means that you cannot work
on objects in one method call that were created by another
call.</para>
</listitem>
<listitem>
<para>By contrast, the VirtualBox Main API, being expressed in
COM, is object-oriented and works entirely on objects, which
are grouped into public interfaces, which in turn have
attributes and methods associated with them.</para>
</listitem>
</itemizedlist> For the VirtualBox web service, this results in
three fundamental conventions:<orderedlist>
<listitem>
<para>All <emphasis role="bold">function names</emphasis> in
the VirtualBox web service consist of an interface name and a
method name, joined together by an underscore. This is because
there are only functions ("operations") in WSDL, but no
classes, interfaces, or methods.</para>
<para>In addition, all calls to the VirtualBox web service
(except for logon, see below) take a <emphasis
role="bold">managed object reference</emphasis> as the first
argument, representing the object upon which the underlying
method is invoked. (Managed object references are explained in
detail below; see <xref
linkend="managed-object-references" />.)</para>
<para>So, when one would normally code, in the pseudo-code of
an object-oriented language, to invoke a method upon an
object:<screen>IMachine machine;
<para>In the VirtualBox web service, this looks something like
this (again, pseudo-code):<screen>IMachineRef machine;
result = IMachine_getName(machine);</screen></para>
</listitem>
<listitem>
<para>To make the web service stateful, and objects persistent
between method calls, the VirtualBox web service introduces a
<emphasis role="bold">session manager</emphasis> (by way of
the <xref linkend="IWebsessionManager"
xreflabel="IWebsessionManager" /> interface), which manages
object references. Any client wishing to interact with the web
service must first log on to the session manager and in turn
receives a managed object reference to an object that supports
the <xref linkend="IVirtualBox" xreflabel="IVirtualBox" />
interface (the basic interface in the Main API).</para>
</listitem>
</orderedlist></para>
<para>In other words, as opposed to other web services, <emphasis
role="bold">the VirtualBox web service is both object-oriented and
stateful.</emphasis></para>
</sect3>
<sect3>
<title>Example: A typical web service client session</title>
<para>A typical short web service session to retrieve the version
number of the VirtualBox web service (to be precise, the underlying
Main API version number) looks like this:<orderedlist>
<listitem>
<para>A client logs on to the web service by calling <xref
linkend="IWebsessionManager__logon"
xreflabel="IWebsessionManager::logon()" /> with a valid user
name and password. See <xref linkend="websrv_authenticate" />
for details about how authentication works.</para>
</listitem>
<listitem>
<para>On the server side,
<computeroutput>vboxwebsrv</computeroutput> creates a session,
which persists until the client calls <xref
linkend="IWebsessionManager__logoff"
xreflabel="IWebsessionManager::logoff()" /> or the session
times out after a configurable period of inactivity (see <xref
linkend="vboxwebsrv-ref" />).</para>
<para>For the new session, the web service creates an instance
of <xref linkend="IVirtualBox" xreflabel="IVirtualBox" />.
This interface is the most central one in the Main API and
allows access to all other interfaces, either through
attributes or method calls. For example, IVirtualBox contains
a list of all virtual machines that are currently registered
(as they would be listed on the left side of the VirtualBox
main program).</para>
<para>The web service then creates a managed object reference
for this instance of IVirtualBox and returns it to the calling
client, which receives it as the return value of the logon
call. Something like this:</para>
<screen>string oVirtualBox;
oVirtualBox = webservice.IWebsessionManager_logon("user", "pass");</screen>
<para>(The managed object reference "oVirtualBox" is just a
string consisting of digits and dashes. However, it is a
string with a meaning and will be checked by the web service.
For details, see below. As hinted above, <xref
linkend="IWebsessionManager__logon"
xreflabel="IWebsessionManager::logon()" /> is the
<emphasis>only</emphasis> operation provided by the web
service which does not take a managed object reference as the
first argument!)</para>
</listitem>
<listitem>
<para>The VirtualBox Main API documentation says that the
<computeroutput>IVirtualBox</computeroutput> interface has a
<xref linkend="IVirtualBox__version" xreflabel="version" />
attribute, which is a string. For each attribute, there is a
"get" and a "set" method in COM, which maps to according
operations in the web service. So, to retrieve the "version"
attribute of this <computeroutput>IVirtualBox</computeroutput>
object, the web service client does this:<screen>string version;
version = webservice.IVirtualBox_getVersion(oVirtualBox);
print version;</screen></para>
<para>And it will print
"$VBOX_VERSION_MAJOR.$VBOX_VERSION_MINOR.$VBOX_VERSION_BUILD".</para>
</listitem>
<listitem>
<para>The web service client calls <xref
linkend="IWebsessionManager__logoff"
xreflabel="IWebsessionManager::logoff()" /> with the
VirtualBox managed object reference. This will clean up all
allocated resources.</para>
</listitem>
</orderedlist></para>
</sect3>
<sect3 id="managed-object-references">
<title>Managed object references</title>
<para>To a web service client, a managed object reference looks like
a string: two 64-bit hex numbers separated by a dash. This string,
however, represents a COM object that "lives" in the web service
process. The two 64-bit numbers encoded in the managed object
reference represent a session ID (which is the same for all objects
in the same web service session, i.e. for all objects after one
logon) and a unique object ID within that session.</para>
<para>Managed object references are created in two
situations:<orderedlist>
<listitem>
<para>When a client logs on, by calling <xref
linkend="IWebsessionManager__logon"
xreflabel="IWebsessionManager::logon()" />.</para>
<para>Upon logon, the websession manager creates one instance
of <xref linkend="IVirtualBox" xreflabel="IVirtualBox" /> and
another object of <xref linkend="ISession"
xreflabel="ISession" /> representing the web service session.
This can be retrieved using <xref
linkend="IWebsessionManager__getSessionObject"
xreflabel="IWebsessionManager::getSessionObject()" />.</para>
<para>(Technically, there is always only one <xref
linkend="IVirtualBox" xreflabel="IVirtualBox" /> object, which
is shared between all sessions and clients, as it is a COM
singleton. However, each session receives its own managed
object reference to it. The <xref linkend="ISession"
xreflabel="ISession" /> object, however, is created and
destroyed for each session.)</para>
</listitem>
<listitem>
<para>Whenever a web service clients invokes an operation
whose COM implementation creates COM objects.</para>
<para>For example, <xref linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine()" /> creates a new
instance of <xref linkend="IMachine" xreflabel="IMachine" />;
the COM object returned by the COM method call is then wrapped
into a managed object reference by the web server, and this
reference is returned to the web service client.</para>
</listitem>
</orderedlist></para>
<para>Internally, in the web service process, each managed object
reference is simply a small data structure, containing a COM pointer
to the "real" COM object, the web session ID and the object ID. This
structure is allocated on creation and stored efficiently in hashes,
so that the web service can look up the COM object quickly whenever
a web service client wishes to make a method call. The random
session ID also ensures that one web service client cannot intercept
the objects of another.</para>
<para>Managed object references are not destroyed automatically and
must be released by explicitly calling <xref
linkend="IManagedObjectRef__release"
xreflabel="IManagedObjectRef::release()" />. This is important, as
otherwise hundreds or thousands of managed object references (and
corresponding COM objects, which can consume much more memory!) can
pile up in the web service process and eventually cause it to deny
service.</para>
<para>To reiterate: The underlying COM object, which the reference
points to, is only freed if the managed object reference is
released. It is therefore vital that web service clients properly
clean up after the managed object references that are returned to
them.</para>
<para>When a web service client calls <xref
linkend="IWebsessionManager__logoff"
xreflabel="IWebsessionManager::logoff()" />, all managed object
references created during the session are automatically freed. For
short-lived sessions that do not create a lot of objects, logging
off may therefore be sufficient, although it is certainly not "best
practice".</para>
</sect3>
<sect3>
<title>Some more detail about web service operation</title>
<sect4 id="soap">
<title>SOAP messages</title>
<para>Whenever a client makes a call to a web service, this
involves a complicated procedure internally. These calls are
remote procedure calls. Each such procedure call typically
consists of two "message" being passed, where each message is a
plain-text HTTP request with a standard HTTP header and a special
XML document following. This XML document encodes the name of the
procedure to call and the argument names and values passed to
it.</para>
<para>To give you an idea of what such a message looks like,
assuming that a web service provides a procedure called
"SayHello", which takes a string "name" as an argument and returns
"Hello" with a space and that name appended, the request message
could look like this:</para>
<para><screen><?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:test="http://test/">
<SOAP-ENV:Body>
<test:SayHello>
<name>Peter</name>
</test:SayHello>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope></screen>A similar message -- the "response" message
-- would be sent back from the web service to the client,
containing the return value "Hello Peter".</para>
<para>Most programming languages provide automatic support to
generate such messages whenever code in that programming language
makes such a request. In other words, these programming languages
allow for writing something like this (in pseudo-C++ code):</para>
<para><screen>webServiceClass service("localhost", 18083); // server and port
would, for these two pseudo-lines, automatically perform these
steps:</para>
<para><orderedlist>
<listitem>
<para>prepare a connection to a web service running on port
18083 of "localhost";</para>
</listitem>
<listitem>
<para>for the <computeroutput>SayHello()</computeroutput>
function of the web service, generate a SOAP message like in
the above example by encoding all arguments of the remote
procedure call (which could involve all kinds of type
conversions and complex marshalling for arrays and
structures);</para>
</listitem>
<listitem>
<para>connect to the web service via HTTP and send that
message;</para>
</listitem>
<listitem>
<para>wait for the web service to send a response
message;</para>
</listitem>
<listitem>
<para>decode that response message and put the return value
of the remote procedure into the "result" variable.</para>
</listitem>
</orderedlist></para>
</sect4>
<sect4 id="wsdl">
<title>Service descriptions in WSDL</title>
<para>In the above explanations about SOAP, it was left open how
the programming language learns about how to translate function
calls in its own syntax into proper SOAP messages. In other words,
the programming language needs to know what operations the web
service supports and what types of arguments are required for the
operation's data in order to be able to properly serialize and
deserialize the data to and from the web service. For example, if
a web service operation expects a number in "double" floating
point format for a particular parameter, the programming language
cannot send to it a string instead.</para>
<para>For this, the Web Service Definition Language (WSDL) was
invented, another XML substandard that describes exactly what
operations the web service supports and, for each operation, which
parameters and types are needed with each request and response
message. WSDL descriptions can be incredibly verbose, and one of
the few good things that can be said about this standard is that
it is indeed supported by most programming languages.</para>
<para>So, if it is said that a programming language "supports" web
services, this typically means that a programming language has
support for parsing WSDL files and somehow integrating the remote
procedure calls into the native language syntax -- for example,
like in the Java sample shown in <xref
linkend="webservice-java-sample" />.</para>
<para>For details about how programming languages support web
services, please refer to the documentation that comes with the
individual languages. Here are a few pointers:</para>
<orderedlist>
<listitem>
<para>For <emphasis role="bold">C++,</emphasis> among many
others, the gSOAP toolkit is a good option. Parts of gSOAP are
also used in VirtualBox to implement the VirtualBox web
service.</para>
</listitem>
<listitem>
<para>For <emphasis role="bold">Java,</emphasis> there are
several implementations already described in this document
(see <xref linkend="glue-jax-ws" /> and <xref
linkend="webservice-java-sample" />).</para>
</listitem>
<listitem>
<para><emphasis role="bold">Perl</emphasis> supports WSDL via
the SOAP::Lite package. This in turn comes with a tool called
to turn any WSDL file into a Perl package that you can import.
(You can also import any WSDL file "live" by having it parsed
every time the script runs, but that can take a while.) You
can then code (again, assuming the above example):<screen>my $result = servicename->sayHello("Peter");</screen></para>
<para>A sample that uses SOAP::Lite was described in <xref
linkend="raw-webservice-perl" />.</para>
</listitem>
</orderedlist>
</sect4>
</sect3>
</sect2>
</sect1>
<sect1 id="api_com">
<para>If you do not require <emphasis>remote</emphasis> procedure calls
such as those offered by the VirtualBox web service, and if you know
Python or C++ as well as COM, you might find it preferable to program
VirtualBox's Main API directly via COM.</para>
<para>COM stands for "Component Object Model" and is a standard
originally introduced by Microsoft in the 1990s for Microsoft Windows.
It allows for organizing software in an object-oriented way and across
processes; code in one process may access objects that live in another
process.</para>
<para>COM has several advantages: it is language-neutral, meaning that
even though all of VirtualBox is internally written in C++, programs
written in other languages could communicate with it. COM also cleanly
separates interface from implementation, so that external programs need
not know anything about the messy and complicated details of VirtualBox
internals.</para>
<para>On a Windows host, all parts of VirtualBox will use the COM
functionality that is native to Windows. On other hosts (including
Linux), VirtualBox comes with a built-in implementation of XPCOM, as
originally created by the Mozilla project, which we have enhanced to
support interprocess communication on a level comparable to Microsoft
COM. Internally, VirtualBox has an abstraction layer that allows the
same VirtualBox code to work both with native COM as well as our XPCOM
implementation.</para>
<sect2 id="pycom">
<title>Python COM API</title>
<para>On Windows, Python scripts can use COM and VirtualBox interfaces
to control almost all aspects of virtual machine execution. As an
example, use the following commands to instantiate the VirtualBox
object and start a VM: <screen>
session = win32com.client.Dispatch("VirtualBox.Session")
mach = vbox.findMachine("uuid or name of machine to start")
progress = mach.launchVMProcess(session, "gui", "")
</screen> Also, see
for more advanced usage scenarious. However, unless you have specific
requirements, we strongly recommend to use the generic glue layer
described in the next section to access MS COM objects.</para>
</sect2>
<sect2 id="glue-python">
<title>Common Python bindings layer</title>
<para>As different wrappers ultimately provide access to the same
underlying API, and to simplify porting and development of Python
application using the VirtualBox Main API, we developed a common glue
layer that abstracts out most platform-specific details from the
application and allows the developer to focus on application logic.
The VirtualBox installer automatically sets up this glue layer for the
system default Python install. See below for details on how to set up
the glue layer if you want to use a different Python
installation.</para>
<para>In this layer, the class
<computeroutput>VirtualBoxManager</computeroutput> hides most
platform-specific details. It can be used to access both the local
(COM) and the web service based API. The following code can be used by
an application to use the glue layer.</para>
<screen># This code assumes vboxapi.py from VirtualBox distribution
# being in PYTHONPATH, or installed system-wide
from vboxapi import VirtualBoxManager
# This code initializes VirtualBox manager with default style
# and parameters
virtualBoxManager = VirtualBoxManager(None, None)
# Alternatively, one can be more verbose, and initialize
# glue with web service backend, and provide authentication
# information
virtualBoxManager = VirtualBoxManager("WEBSERVICE",
{'url':'http://myhost.com::18083/',
'user':'me',
'password':'secret'}) </screen>
<para>We supply the <computeroutput>VirtualBoxManager</computeroutput>
constructor with 2 arguments: style and parameters. Style defines
which bindings style to use (could be "MSCOM", "XPCOM" or
"WEBSERVICE"), and if set to <computeroutput>None</computeroutput>
defaults to usable platform bindings (MS COM on Windows, XPCOM on
other platforms). The second argument defines parameters, passed to
the platform-specific module, as we do in the second example, where we
pass username and password to be used to authenticate against the web
service.</para>
<para>After obtaining the
<computeroutput>VirtualBoxManager</computeroutput> instance, one can
perform operations on the IVirtualBox class. For example, the
following code will a start virtual machine by name or ID:</para>
<screen>from vboxapi import VirtualBoxManager
mgr = VirtualBoxManager(None, None)
vbox = mgr.vbox
name = "Linux"
mach = vbox.findMachine(name)
session = mgr.mgr.getSessionObject(vbox)
progress = mach.launchVMProcess(session, "gui", "")
mgr.closeMachineSession(session)
</screen>
<para>
Following code will print all registered machines and their log folders
</para>
<screen>from vboxapi import VirtualBoxManager
mgr = VirtualBoxManager(None, None)
vbox = mgr.vbox
for m in mgr.getArray(vbox, 'machines'):
print "Machine '%s' logs in '%s'" %(m.name, m.logFolder)
</screen>
<para>Code above demonstartes cross-platform access to array properties
(certain limitations prevent one from using
available virtual machines in case of XPCOM), and a mechanism of
uniform session creation and closing
<para>In case you want to use the glue layer with a different Python
installation, use these steps in a shell to add the necessary
files:</para>
# PYTHON vboxapisetup.py install</screen>
</sect2>
<sect2 id="cppcom">
<title>C++ COM API</title>
<para>C++ is the language that VirtualBox itself is written in, so C++
is the most direct way to use the Main API -- but it is not
necessarily the easiest, as using COM and XPCOM has its own set of
complications.</para>
<para>VirtualBox ships with sample programs that demonstrate how to
use the Main API to implement a number of tasks on your host platform.
These samples can be found in the
Linux, Mac OS X and Solaris and
The two samples are actually different, because the one for Windows
uses native COM, whereas the other uses our XPCOM implementation, as
described above.</para>
<para>Since COM and XPCOM are conceptually very similar but vary in
the implementation details, we have created a "glue" layer that
shields COM client code from these differences. All VirtualBox uses is
this glue layer, so the same code written once works on both Windows
hosts (with native COM) as well as on other hosts (with our XPCOM
implementation). It is recommended to always use this glue code
instead of using the COM and XPCOM APIs directly, as it is very easy
to make your code completely independent from the platform it is
running on.<!-- A third sample,
<computeroutput>tstVBoxAPIGlue.cpp</computeroutput>, illustrates how to
use the glue layer.
--></para>
<para>In order to encapsulate platform differences between Microsoft
COM and XPCOM, the following items should be kept in mind when using
the glue layer:</para>
<para><orderedlist>
<listitem>
<para><emphasis role="bold">Attribute getters and
setters.</emphasis> COM has the notion of "attributes" in
interfaces, which roughly compare to C++ member variables in
classes. The difference is that for each attribute declared in
an interface, COM automatically provides a "get" method to
return the attribute's value. Unless the attribute has been
marked as "readonly", a "set" attribute is also provided.</para>
<para>To illustrate, the IVirtualBox interface has a "version"
attribute, which is read-only and of the "wstring" type (the
standard string type in COM). As a result, you can call the
"get" method for this attribute to retrieve the version number
of VirtualBox.</para>
<para>Unfortunately, the implementation differs between COM and
XPCOM. Microsoft COM names the "get" method like this:
<computeroutput>get_Attribute()</computeroutput>, whereas XPCOM
uses this syntax:
<computeroutput>GetAttribute()</computeroutput> (and accordingly
for "set" methods). To hide these differences, the VirtualBox
glue code provides the
<computeroutput>COMGETTER(attrib)</computeroutput> and
<computeroutput>COMSETTER(attrib)</computeroutput> macros. So,
<computeroutput>COMGETTER(version)()</computeroutput> (note, two
pairs of brackets) expands to
<computeroutput>get_Version()</computeroutput> on Windows and
<computeroutput>GetVersion()</computeroutput> on other
platforms.</para>
</listitem>
<listitem>
<para><emphasis role="bold">Unicode conversions.</emphasis>
While the rest of the modern world has pretty much settled on
encoding strings in UTF-8, COM, unfortunately, uses UCS-16
encoding. This requires a lot of conversions, in particular
between the VirtualBox Main API and the Qt GUI, which, like the
rest of Qt, likes to use UTF-8.</para>
<para>To facilitate these conversions, VirtualBox provides the
<computeroutput>com::Bstr</computeroutput> and
<computeroutput>com::Utf8Str</computeroutput> classes, which
support all kinds of conversions back and forth.</para>
</listitem>
<listitem>
<para><emphasis role="bold">COM autopointers.</emphasis>
Possibly the greatest pain of using COM -- reference counting --
is alleviated by the
<computeroutput>ComPtr<></computeroutput> template
the glue layer.</para>
</listitem>
</orderedlist></para>
</sect2>
<sect2 id="event-queue">
<title>Event queue processing</title>
<para>Both VirtualBox client programs and frontends should
periodically perform processing of the main event queue, and do that
OS application this happens automatically in the GUI's dispatch loop.
However, for CLI only application, the appropriate actions have to be
taken. For C++ applications, the VirtualBox SDK provided glue method
<screen>
int EventQueue::processEventQueue(uint32_t cMsTimeout)
</screen> can be used for both blocking and non-blocking operations.
For the Python bindings, a common layer provides the method <screen>
</screen> with similar semantics.</para>
<para>Things get somewhat more complicated for situations where an
application using VirtualBox cannot directly control the main event
loop and the main event queue is separated from the event queue of the
programming librarly (for example in case of Qt on Unix platforms). In
such a case, the application developer is advised to use a
queue checks either based on periodical timer events delivered to the
main thread, or by using custom platform messages to notify the main
thread when events are available. See the VBoxSDL and Qt (VirtualBox)
frontends as examples.</para>
</sect2>
<sect2 id="vbcom">
<title>Visual Basic and Visual Basic Script (VBS) on Windows
hosts</title>
<para>On Windows hosts, one can control some of the VirtualBox Main
API functionality from VBS scripts, and pretty much everything from
Visual Basic programs.<footnote>
<para>The difference results from the way VBS treats COM
safearrays, which are used to keep lists in the Main API. VBS
expects every array element to be a
<computeroutput>VARIANT</computeroutput>, which is too strict a
limitation for any high performance API. We may lift this
restriction for interface APIs in a future version, or
alternatively provide conversion APIs.</para>
</footnote></para>
<para>VBS is scripting language available in any recent Windows
environment. As an example, the following VBS code will print
VirtualBox version: <screen>
set vb = CreateObject("VirtualBox.VirtualBox")
Wscript.Echo "VirtualBox version " & vb.version
</screen> See
for the complete sample.</para>
<para>Visual Basic is a popular high level language capable of
accessing COM objects. The following VB code will iterate over all
available virtual machines:<screen>
Dim vb As VirtualBox.IVirtualBox
vb = CreateObject("VirtualBox.VirtualBox")
machines = ""
Next
</screen> See
for the complete sample.</para>
</sect2>
<sect2 id="cbinding">
<title>C binding to XPCOM API</title>
<note>
<para>This section currently applies to Linux hosts only.</para>
</note>
<para>Starting with version 2.2, VirtualBox offers a C binding for the
XPCOM API.</para>
<para>The C binding provides a layer enabling object creation, method
invocation and attribute access from C.</para>
<sect3 id="c-gettingstarted">
<title>Getting started</title>
<para>The following sections describe how to use the C binding in a
C program.</para>
<para>For Linux, a sample program is provided which demonstrates use
of the C binding to initialize XPCOM, get handles for VirtualBox and
Session objects, make calls to list and start virtual machines, and
uninitialize resources when done. The program uses the VBoxGlue
library to open the C binding layer during runtime.</para>
<para>The sample program
<computeroutput>tstXPCOMCGlue</computeroutput> is located in the bin
directory and can be run without arguments. It lists registered
machines on the host along with some additional information and ask
for a machine to start. The source for this program is available in
directory. The source for the VBoxGlue library is available in the
directory.</para>
</sect3>
<sect3 id="c-initialization">
<title>XPCOM initialization</title>
<para>Just like in C++, XPCOM needs to be initialized before it can
provides the interface to the C binding. Here's how to initialize
XPCOM:</para>
<screen>#include "VBoxCAPI_v2_5.h"
...
PCVBOXXPCOM g_pVBoxFuncs = NULL;
IVirtualBox *vbox = NULL;
ISession *session = NULL;
/*
* VBoxGetXPCOMCFunctions() is the only function exported by
* VBoxXPCOMC.so and the only one needed to make virtualbox
* work with C. This functions gives you the pointer to the
* function table (g_pVBoxFuncs).
*
* Once you get the function table, then how and which functions
* to use is explained below.
*
* g_pVBoxFuncs->pfnComInitialize does all the necessary startup
* action and provides us with pointers to vbox and session handles.
* It should be matched by a call to g_pVBoxFuncs->pfnComUninitialize()
* when done.
*/
g_pVBoxFuncs = VBoxGetXPCOMCFunctions(VBOX_XPCOMC_VERSION);
g_pVBoxFuncs->pfnComInitialize(&vbox, &session);</screen>
<para>If either <computeroutput>vbox</computeroutput> or
<computeroutput>session</computeroutput> is still
<computeroutput>NULL</computeroutput>, initialization failed and the
XPCOM API cannot be used.</para>
</sect3>
<sect3 id="c-invocation">
<title>XPCOM method invocation</title>
<para>Method invocation is straightforward. It looks pretty much
like the C++ way, augmented with an extra indirection due to
accessing the vtable and passing a pointer to the object as the
first argument to serve as the <computeroutput>this</computeroutput>
pointer.</para>
<para>Using the C binding, all method invocations return a numeric
result code.</para>
<para>If an interface is specified as returning an object, a pointer
to a pointer to the appropriate object must be passed as the last
argument. The method will then store an object pointer in that
location.</para>
<para>In other words, to call an object's method what you need
is</para>
<screen>IObject *object;
nsresult rc;
...
/*
* Calling void IObject::method(arg, ...)
*/
rc = object->vtbl->Method(object, arg, ...);
...
IFoo *foo;
/*
* Calling IFoo IObject::method(arg, ...)
*/
rc = object->vtbl->Method(object, args, ..., &foo);</screen>
<para>As a real-world example of a method invocation, let's call
<xref linkend="IMachine__launchVMProcess"
xreflabel="IMachine::launchVMProcess" /> which returns an
IProgress object. Note again that the method name is
capitalized.</para>
<screen>IProgress *progress;
...
rc = vbox->vtbl->LaunchVMProcess(
machine, /* this */
session, /* arg 1 */
sessionType, /* arg 2 */
env, /* arg 3 */
&progress /* Out */
);
</screen>
</sect3>
<sect3 id="c-attributes">
<title>XPCOM attribute access</title>
<para>A construct similar to calling non-void methods is used to
access object attributes. For each attribute there exists a getter
method, the name of which is composed of
<computeroutput>Get</computeroutput> followed by the capitalized
attribute name. Unless the attribute is read-only, an analogous
<computeroutput>Set</computeroutput> method exists. Let's apply
these rules to read the <xref linkend="IVirtualBox__revision"
xreflabel="IVirtualBox::revision" /> attribute.</para>
<para>Using the <computeroutput>IVirtualBox</computeroutput> handle
<computeroutput>vbox</computeroutput> obtained above, calling its
<computeroutput>GetRevision</computeroutput> method looks like
this:</para>
<screen>PRUint32 rev;
rc = vbox->vtbl->GetRevision(vbox, &rev);
if (NS_SUCCEEDED(rc))
{
printf("Revision: %u\n", (unsigned)rev);
}
</screen>
<para>All objects with their methods and attributes are documented
in <xref linkend="sdkref_classes" />.</para>
</sect3>
<sect3 id="c-string-handling">
<title>String handling</title>
<para>When dealing with strings you have to be aware of a string's
encoding and ownership.</para>
<para>Internally, XPCOM uses UTF-16 encoded strings. A set of
conversion functions is provided to convert other encodings to and
from UTF-16. The type of a UTF-16 character is
<computeroutput>PRUnichar</computeroutput>. Strings of UTF-16
characters are arrays of that type. Most string handling functions
take pointers to that type. Prototypes for the following conversion
functions are declared in
<sect4>
<title>Conversion of UTF-16 to and from UTF-8</title>
<screen>int (*pfnUtf16ToUtf8)(const PRUnichar *pwszString, char **ppszString);
int (*pfnUtf8ToUtf16)(const char *pszString, PRUnichar **ppwszString);
</screen>
</sect4>
<sect4>
<title>Ownership</title>
<para>The ownership of a string determines who is responsible for
releasing resources associated with the string. Whenever XPCOM
creates a string, ownership is transferred to the caller. To avoid
resource leaks, the caller should release resources once the
string is no longer needed.</para>
</sect4>
</sect3>
<sect3 id="c-uninitialization">
<title>XPCOM uninitialization</title>
<para>Uninitialization is performed by
<computeroutput>g_pVBoxFuncs->pfnComUninitialize().</computeroutput>
If your program can exit from more than one place, it is a good idea
to install this function as an exit handler with Standard C's
<computeroutput>atexit()</computeroutput> just after calling
<computeroutput>g_pVBoxFuncs->pfnComInitialize()</computeroutput>
#include <stdio.h>
...
/*
* Make sure g_pVBoxFuncs->pfnComUninitialize() is called at exit, no
* matter if we return from the initial call to main or call exit()
* somewhere else. Note that atexit registered functions are not
* called upon abnormal termination, i.e. when calling abort() or
* signal(). Separate provisions must be taken for these cases.
*/
if (atexit(g_pVBoxFuncs->pfnComUninitialize()) != 0) {
fprintf(stderr, "failed to register g_pVBoxFuncs->pfnComUninitialize()\n");
exit(EXIT_FAILURE);
}
</screen></para>
<para>Another idea would be to write your own <computeroutput>void
myexit(int status)</computeroutput> function, calling
<computeroutput>g_pVBoxFuncs->pfnComUninitialize()</computeroutput>
followed by the real <computeroutput>exit()</computeroutput>, and
use it instead of <computeroutput>exit()</computeroutput> throughout
your program and at the end of
<computeroutput>main.</computeroutput></para>
<para>If you expect the program to be terminated by a signal (e.g.
user types CTRL-C sending SIGINT) you might want to install a signal
handler setting a flag noting that a signal was sent and then
calling
<computeroutput>g_pVBoxFuncs->pfnComUninitialize()</computeroutput>
later on (usually <emphasis>not</emphasis> from the handler itself
.)</para>
<para>That said, if a client program forgets to call
<computeroutput>g_pVBoxFuncs->pfnComUninitialize()</computeroutput>
before it terminates, there is a mechanism in place which will
eventually release references held by the client. You should not
rely on this, however.</para>
</sect3>
<sect3 id="c-linking">
<title>Compiling and linking</title>
<para>A program using the C binding has to open the library during
runtime using the help of glue code provided and as shown in the
Compilation and linking can be achieved, e.g., with a makefile
fragment similar to</para>
<screen># Where is the XPCOM include directory?
INCS_XPCOM = /include
# Where is the glue code directory?
GLUE_DIR = ..
GLUE_INC = -I..
#Compile Glue Library
VBoxXPCOMCGlue.o: $(GLUE_DIR)/VBoxXPCOMCGlue.c
$(CC) $(CFLAGS) $(INCS_XPCOM) $(GLUE_INC) -o $@ -c $<
# Compile.
$(CC) $(CFLAGS) $(INCS_XPCOM) $(GLUE_INC) -o $@ -c $<
# Link.
program: program.o VBoxXPCOMCGlue.o
$(CC) -o $@ $^ -ldl</screen>
</sect3>
</sect2>
</sect1>
</chapter>
<chapter id="concepts">
<title>Basic VirtualBox concepts; some examples</title>
<para>The following explains some basic VirtualBox concepts such as the
VirtualBox object, sessions and how virtual machines are manipulated and
launched using the Main API. The coding examples use a pseudo-code style
closely related to the object-oriented web service (OOWS) for JAX-WS.
Depending on which environment you are using, you will need to adjust the
examples.</para>
<sect1>
<title>Obtaining basic machine information. Reading attributes</title>
<para>Any program using the Main API will first need access to the
global VirtualBox object (see <xref linkend="IVirtualBox"
xreflabel="IVirtualBox" />), from which all other functionality of the
API is derived. With the OOWS for JAX-WS, this is returned from the
<xref linkend="IWebsessionManager__logon"
xreflabel="IWebsessionManager::logon()" /> call.</para>
<para>To enumerate virtual machines, one would look at the "machines"
array attribute in the VirtualBox object (see <xref
linkend="IVirtualBox__machines" xreflabel="IVirtualBox::machines" />).
This array contains all virtual machines currently registered with the
host, each of them being an instance of <xref linkend="IMachine"
xreflabel="IMachine" />. From each such instance, one can query
additional information, such as the UUID, the name, memory, operating
system and more by looking at the attributes; see the attributes list in
<xref linkend="IMachine" xreflabel="IMachine documentation" />.</para>
<para>As mentioned in the preceding chapters, depending on your
programming environment, attributes are mapped to corresponding "get"
and (if the attribute is not read-only) "set" methods. So when the
documentation says that IMachine has a "<xref linkend="IMachine__name"
xreflabel="name" />" attribute, this means you need to code something
like the following to get the machine's name:<screen>IMachine machine = ...;
String name = machine.getName();</screen>Boolean attribute getters can
sometimes be called <computeroutput>isAttribute()</computeroutput> due
to JAX-WS naming conventions.</para>
</sect1>
<sect1>
<title>Changing machine settings. Sessions</title>
<para>As said in the previous section, to read a machine's attribute,
one invokes the corresponding "get" method. One would think that to
change settings of a machine, it would suffice to call the corresponding
"set" method -- for example, to set a VM's memory to 1024 MB, one would
call <computeroutput>setMemorySize(1024)</computeroutput>. Try that, and
you will get an error: "The machine is not mutable."</para>
<para>So unfortunately, things are not that easy. VirtualBox is a
complicated environment in which multiple processes compete for possibly
the same resources, especially machine settings. As a result, machines
must be "locked" before they can either be modified or started. This is
to prevent multiple processes from making conflicting changes to a
machine: it should, for example, not be allowed to change the memory
size of a virtual machine while it is running. (You can't add more
memory to a real computer while it is running either, at least not to an
ordinary PC.) Also, two processes must not change settings at the same
time, or start a machine at the same time.</para>
<para>These requirements are implemented in the Main API by way of
"sessions", in particular, the <xref linkend="ISession"
xreflabel="ISession" /> interface. Each process which talks to
VirtualBox needs its own instance of ISession. In the web service, you
cannot create such an object, but
<computeroutput>vboxwebsrv</computeroutput> creates one for you when you
log on, which you can obtain by calling <xref
linkend="IWebsessionManager__getSessionObject"
xreflabel="IWebsessionManager::getSessionObject()" />.</para>
<para>This session object must then be used like a mutex semaphore in
common programming environments. Before you can change machine settings,
you must write-lock the machine by calling <xref
linkend="IMachine__lockMachine" xreflabel="IMachine::lockMachine()" />
with your process's session object.</para>
<para>After the machine has been locked, the <xref
linkend="ISession__machine" xreflabel="ISession::machine" /> attribute
contains a copy of the original IMachine object upon which the session
was opened, but this copy is "mutable": you can invoke "set" methods on
it.</para>
<para>When done making the changes to the machine, you must call <xref
linkend="IMachine__saveSettings"
xreflabel="IMachine::saveSettings()" />, which will copy the changes you
have made from your "mutable" machine back to the real machine and write
them out to the machine settings XML file. This will make your changes
permanent.</para>
<para>Finally, it is important to always unlock the machine again, by
calling <xref linkend="ISession__unlockMachine"
xreflabel="ISession::unlockMachine()" />. Otherwise, when the calling
process end, the machine will receive the "aborted" state, which can
lead to loss of data.</para>
<para>So, as an example, the sequence to change a machine's memory to
1024 MB is something like this:<screen>IWebsessionManager mgr ...;
IVirtualBox vbox = mgr.logon(user, pass);
...
IMachine machine = ...; // read-only machine
ISession session = mgr.getSessionObject();
machine.lockMachine(session, LockType.Write); // machine is now locked for writing
IMachine mutable = session.getMachine(); // obtain the mutable machine copy
mutable.setMemorySize(1024);
mutable.saveSettings(); // write settings to XML
</sect1>
<sect1>
<title>Launching virtual machines</title>
<para>To launch a virtual machine, you call <xref
linkend="IMachine__launchVMProcess"
xreflabel="IMachine::launchVMProcess()" />. In doing so, the caller
instructs the VirtualBox engine to start a new process with the virtual
machine in it, since to the host, each virtual machine looks like a
single process, even if it has hundreds of its own processes inside.
(This new VM process in turn obtains a write lock on the machine, as
described above, to prevent conflicting changes from other processes;
this is why opening another session will fail while the VM is
running.)</para>
<para>Starting a machine looks something like this:<screen>IWebsessionManager mgr ...;
IVirtualBox vbox = mgr.logon(user, pass);
...
IMachine machine = ...; // read-only machine
ISession session = mgr.getSessionObject();
IProgress prog = machine.launchVMProcess(session,
"gui", // session type
""); // possibly environment setting
prog.waitForCompletion(10000); // give the process 10 secs
if (prog.getResultCode() != 0) // check success
<para>The caller's session object can then be used as a sort of remote
control to the VM process that was launched. It contains a "console"
object (see <xref linkend="ISession__console"
xreflabel="ISession::console" />) with which the VM can be paused,
stopped, snapshotted or other things.</para>
</sect1>
<sect1>
<title>VirtualBox events</title>
<para>In VirtualBox, "events" provide a uniform mechanism to register
for and consume specific events. A VirtualBox client can register an
"event listener" (represented by the <xref linkend="IEventListener"
xreflabel="IEventListener" /> interface), which will then get notified
by the server when an event (represented by the <xref linkend="IEvent"
xreflabel="IEvent" /> interface) happens.</para>
<para>The IEvent interface is an abstract parent interface for all
events that can occur in VirtualBox. The actual events that the server
sends out are then of one of the specific subclasses, for example <xref
linkend="IMachineStateChangedEvent"
xreflabel="IMachineStateChangedEvent" /> or <xref
linkend="IMediumChangedEvent" xreflabel="IMediumChangedEvent" />.</para>
<para>As an example, the VirtualBox GUI waits for machine events and can
thus update its display when the machine state changes or machine
settings are modified, even if this happens in another client. This is
how the GUI can automatically refresh its display even if you manipulate
a machine from another client, for example, from VBoxManage.</para>
<para>To register an event listener to listen to events, use code like
this:<screen>EventSource es = console.getEventSource();
IEventListener listener = es.createListener();
VBoxEventType aTypes[] = (VBoxEventType.OnMachineStateChanged);
// list of event types to listen for
es.registerListener(listener, aTypes, false /* active */);
// register passive listener
IEvent ev = es.getEvent(listener, 1000);
// wait up to one second for event to happen
if (ev != null)
{
// downcast to specific event interface (in this case we have only registered
// for one type, otherwise IEvent::type would tell us)
IMachineStateChangedEvent mcse = IMachineStateChangedEvent.queryInterface(ev);
... // inspect and do something
es.eventProcessed(listener, ev);
}
...
<para>A graphical user interface would probably best start its own
thread to wait for events and then process these in a loop.</para>
<para>The events mechanism was introduced with VirtualBox 3.3 and
replaces various callback interfaces which were called for each event in
the interface. The callback mechanism was not compatible with scripting
languages, local Java bindings and remote web services as they do not
support callbacks. The new mechanism with events and event listeners
works with all of these.</para>
<para>To simplify developement of application using events, concept of
event aggregator was introduced. Essentially it's mechanism to aggregate
multiple event sources into single one, and then work with this single
aggregated event source instead of original sources. As an example, one
can evaluate demo recorder in VirtualBox Python shell, shipped with SDK
- it records mouse and keyboard events, represented as separate event
sources. Code is essentially like this:<screen>
listener = console.eventSource.createListener()
agg = console.eventSource.createAggregator([console.keyboard.eventSource, console.mouse.eventSource])
agg.registerListener(listener, [ctx['global'].constants.VBoxEventType_Any], False)
registered = True
end = time.time() + dur
while time.time() < end:
ev = agg.getEvent(listener, 1000)
processEent(ev)
agg.unregisterListener(listener)</screen> Without using aggregators
consumer have to poll on both sources, or start multiple threads to
block on those sources.</para>
</sect1>
</chapter>
<chapter id="vboxshell">
<title>The VirtualBox shell</title>
<para>VirtualBox comes with an extensible shell, which allows you to
control your virtual machines from the command line. It is also a
nontrivial example of how to use the VirtualBox APIs from Python, for all
<para>You can easily extend this shell with your own commands. Create a
below your home directory and put a Python file implementing your shell
extension commands in this directory. This file must contain an array
named <computeroutput>commands</computeroutput> containing your command
definitions: <screen>
commands = {
'cmd1': ['Command cmd1 help', cmd1],
'cmd2': ['Command cmd2 help', cmd2]
}
</screen> For example, to create a command for creating hard drive
images, the following code can be used: <screen>
def createHdd(ctx,args):
# Show some meaningful error message on wrong input
if (len(args) < 3):
print "usage: createHdd sizeM location type"
return 0
# Get arguments
size = int(args[1])
loc = args[2]
if len(args) > 3:
format = args[3]
else:
# And provide some meaningful defaults
format = "vdi"
# Call VirtualBox API, using context's fields
hdd = ctx['vb'].createHardDisk(format, loc)
# Access constants using ctx['global'].constants
progress = hdd.createBaseStorage(size, ctx['global'].constants.HardDiskVariant_Standard)
# use standard progress bar mechanism
ctx['progressBar'](progress)
# Report errors
if not hdd.id:
print "cannot create disk (file %s exist?)" %(loc)
return 0
# Give user some feedback on success too
print "created HDD with id: %s" %(hdd.id)
# 0 means continue execution, other values mean exit from the interpreter
return 0
commands = {
'myCreateHDD': ['Create virtual HDD, createHdd size location type', createHdd]
}
</screen> Just store the above text in the file
<computeroutput>createHdd</computeroutput> (or any other meaningful name)
VirtualBox shell, or just issue the
<computeroutput>reloadExts</computeroutput> command, if the shell is
already running. Your new command will now be available.</para>
</chapter>
<!--$VIRTUALBOX_MAIN_API_REFERENCE-->
<chapter id="hgcm">
<title>Host-Guest Communication Manager</title>
<para>The VirtualBox Host-Guest Communication Manager (HGCM) allows a
guest application or a guest driver to call a host shared library. The
following features of VirtualBox are implemented using HGCM: <itemizedlist>
<listitem>
<para>Shared Folders</para>
</listitem>
<listitem>
<para>Shared Clipboard</para>
</listitem>
<listitem>
<para>Guest configuration interface</para>
</listitem>
</itemizedlist></para>
<para>The shared library contains a so called HGCM service. The guest HGCM
clients establish connections to the service to call it. When calling a
HGCM service the client supplies a function code and a number of
parameters for the function.</para>
<sect1>
<title>Virtual hardware implementation</title>
<para>HGCM uses the VMM virtual PCI device to exchange data between the
guest and the host. The guest always acts as an initiator of requests. A
request is constructed in the guest physical memory, which must be
locked by the guest. The physical address is passed to the VMM device
using a 32 bit <computeroutput>out edx, eax</computeroutput>
instruction. The physical memory must be allocated below 4GB by 64 bit
guests.</para>
<para>The host parses the request header and data and queues the request
for a host HGCM service. The guest continues execution and usually waits
on a HGCM event semaphore.</para>
<para>When the request has been processed by the HGCM service, the VMM
device sets the completion flag in the request header, sets the HGCM
event and raises an IRQ for the guest. The IRQ handler signals the HGCM
event semaphore and all HGCM callers check the completion flag in the
corresponding request header. If the flag is set, the request is
considered completed.</para>
</sect1>
<sect1>
<title>Protocol specification</title>
<para>The HGCM protocol definitions are contained in the
<sect2>
<title>Request header</title>
<para>HGCM request structures contains a generic header
(VMMDevHGCMRequestHeader): <table>
<title>HGCM Request Generic Header</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>size</entry>
<entry>Size of the entire request.</entry>
</row>
<row>
<entry>version</entry>
<entry>Version of the header, must be set to
<computeroutput>0x10001</computeroutput>.</entry>
</row>
<row>
<entry>type</entry>
<entry>Type of the request.</entry>
</row>
<row>
<entry>rc</entry>
<entry>HGCM return code, which will be set by the VMM
device.</entry>
</row>
<row>
<entry>reserved1</entry>
<entry>A reserved field 1.</entry>
</row>
<row>
<entry>reserved2</entry>
<entry>A reserved field 2.</entry>
</row>
<row>
<entry>flags</entry>
<entry>HGCM flags, set by the VMM device.</entry>
</row>
<row>
<entry>result</entry>
<entry>The HGCM result code, set by the VMM device.</entry>
</row>
</tbody>
</tgroup>
</table> <note>
<itemizedlist>
<listitem>
<para>All fields are 32 bit.</para>
</listitem>
<listitem>
<para>Fields from <computeroutput>size</computeroutput> to
<computeroutput>reserved2</computeroutput> are a standard VMM
device request header, which is used for other interfaces as
well.</para>
</listitem>
</itemizedlist>
</note></para>
<para>The <emphasis role="bold">type</emphasis> field indicates the
type of the HGCM request: <table>
<title>Request Types</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name (decimal
value)</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>VMMDevReq_HGCMConnect
(<computeroutput>60</computeroutput>)</entry>
<entry>Connect to a HGCM service.</entry>
</row>
<row>
<entry>VMMDevReq_HGCMDisconnect
(<computeroutput>61</computeroutput>)</entry>
<entry>Disconnect from the service.</entry>
</row>
<row>
<entry>VMMDevReq_HGCMCall32
(<computeroutput>62</computeroutput>)</entry>
<entry>Call a HGCM function using the 32 bit
interface.</entry>
</row>
<row>
<entry>VMMDevReq_HGCMCall64
(<computeroutput>63</computeroutput>)</entry>
<entry>Call a HGCM function using the 64 bit
interface.</entry>
</row>
<row>
<entry>VMMDevReq_HGCMCancel
(<computeroutput>64</computeroutput>)</entry>
<entry>Cancel a HGCM request currently being processed by a
host HGCM service.</entry>
</row>
</tbody>
</tgroup>
</table></para>
<para>The <emphasis role="bold">flags</emphasis> field may contain:
<table>
<title>Flags</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name (hexadecimal
value)</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>VBOX_HGCM_REQ_DONE
(<computeroutput>0x00000001</computeroutput>)</entry>
<entry>The request has been processed by the host
service.</entry>
</row>
<row>
<entry>VBOX_HGCM_REQ_CANCELLED
(<computeroutput>0x00000002</computeroutput>)</entry>
<entry>This request was cancelled.</entry>
</row>
</tbody>
</tgroup>
</table></para>
</sect2>
<sect2>
<title>Connect</title>
<para>The connection request must be issued by the guest HGCM client
before it can call the HGCM service (VMMDevHGCMConnect): <table>
<title>Connect request</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>header</entry>
<entry>The generic HGCM request header with type equal to
VMMDevReq_HGCMConnect
(<computeroutput>60</computeroutput>).</entry>
</row>
<row>
<entry>type</entry>
<entry>The type of the service location information (32
bit).</entry>
</row>
<row>
<entry>location</entry>
<entry>The service location information (128 bytes).</entry>
</row>
<row>
<entry>clientId</entry>
<entry>The client identifier assigned to the connecting
client by the HGCM subsystem (32 bit).</entry>
</row>
</tbody>
</tgroup>
</table> The <emphasis role="bold">type</emphasis> field tells the
HGCM how to look for the requested service: <table>
<title>Location Information Types</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name (hexadecimal
value)</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>VMMDevHGCMLoc_LocalHost
(<computeroutput>0x1</computeroutput>)</entry>
<entry>The requested service is a shared library located on
the host and the location information contains the library
name.</entry>
</row>
<row>
<entry>VMMDevHGCMLoc_LocalHost_Existing
(<computeroutput>0x2</computeroutput>)</entry>
<entry>The requested service is a preloaded one and the
location information contains the service name.</entry>
</row>
</tbody>
</tgroup>
</table> <note>
<para>Currently preloaded HGCM services are hard-coded in
VirtualBox: <itemizedlist>
<listitem>
<para>VBoxSharedFolders</para>
</listitem>
<listitem>
<para>VBoxSharedClipboard</para>
</listitem>
<listitem>
<para>VBoxGuestPropSvc</para>
</listitem>
<listitem>
<para>VBoxSharedOpenGL</para>
</listitem>
</itemizedlist></para>
</note> There is no difference between both types of HGCM services,
only the location mechanism is different.</para>
<para>The client identifier is returned by the host and must be used
in all subsequent requests by the client.</para>
</sect2>
<sect2>
<title>Disconnect</title>
<para>This request disconnects the client and makes the client
identifier invalid (VMMDevHGCMDisconnect): <table>
<title>Disconnect request</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>header</entry>
<entry>The generic HGCM request header with type equal to
VMMDevReq_HGCMDisconnect
(<computeroutput>61</computeroutput>).</entry>
</row>
<row>
<entry>clientId</entry>
<entry>The client identifier previously returned by the
connect request (32 bit).</entry>
</row>
</tbody>
</tgroup>
</table></para>
</sect2>
<sect2>
<title>Call32 and Call64</title>
<para>Calls the HGCM service entry point (VMMDevHGCMCall) using 32 bit
or 64 bit addresses: <table>
<title>Call request</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>header</entry>
<entry>The generic HGCM request header with type equal to
either VMMDevReq_HGCMCall32
(<computeroutput>62</computeroutput>) or
VMMDevReq_HGCMCall64
(<computeroutput>63</computeroutput>).</entry>
</row>
<row>
<entry>clientId</entry>
<entry>The client identifier previously returned by the
connect request (32 bit).</entry>
</row>
<row>
<entry>function</entry>
<entry>The function code to be processed by the service (32
bit).</entry>
</row>
<row>
<entry>cParms</entry>
<entry>The number of following parameters (32 bit). This
value is 0 if the function requires no parameters.</entry>
</row>
<row>
<entry>parms</entry>
<entry>An array of parameter description structures
(HGCMFunctionParameter32 or
HGCMFunctionParameter64).</entry>
</row>
</tbody>
</tgroup>
</table></para>
<para>The 32 bit parameter description (HGCMFunctionParameter32)
consists of 32 bit type field and 8 bytes of an opaque value, so 12
bytes in total. The 64 bit variant (HGCMFunctionParameter64) consists
of the type and 12 bytes of a value, so 16 bytes in total.</para>
<para><table>
<title>Parameter types</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Type</emphasis></entry>
<entry><emphasis role="bold">Format of the
value</emphasis></entry>
</row>
<row>
<entry>VMMDevHGCMParmType_32bit (1)</entry>
<entry>A 32 bit value.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_64bit (2)</entry>
<entry>A 64 bit value.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_PhysAddr (3)</entry>
<entry>A 32 bit size followed by a 32 bit or 64 bit guest
physical address.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr (4)</entry>
<entry>A 32 bit size followed by a 32 bit or 64 bit guest
linear address. The buffer is used both for guest to host
and for host to guest data.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr_In (5)</entry>
<entry>Same as VMMDevHGCMParmType_LinAddr but the buffer is
used only for host to guest data.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr_Out (6)</entry>
<entry>Same as VMMDevHGCMParmType_LinAddr but the buffer is
used only for guest to host data.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr_Locked (7)</entry>
<entry>Same as VMMDevHGCMParmType_LinAddr but the buffer is
already locked by the guest.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr_Locked_In (1)</entry>
<entry>Same as VMMDevHGCMParmType_LinAddr_In but the buffer
is already locked by the guest.</entry>
</row>
<row>
<entry>VMMDevHGCMParmType_LinAddr_Locked_Out (1)</entry>
<entry>Same as VMMDevHGCMParmType_LinAddr_Out but the buffer
is already locked by the guest.</entry>
</row>
</tbody>
</tgroup>
</table></para>
<para>The</para>
</sect2>
<sect2>
<title>Cancel</title>
<para>This request cancels a call request (VMMDevHGCMCancel): <table>
<title>Cancel request</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Name</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>header</entry>
<entry>The generic HGCM request header with type equal to
VMMDevReq_HGCMCancel
(<computeroutput>64</computeroutput>).</entry>
</row>
</tbody>
</tgroup>
</table></para>
</sect2>
</sect1>
<sect1>
<title>Guest software interface</title>
<para>The guest HGCM clients can call HGCM services from both drivers
and applications.</para>
<sect2>
<title>The guest driver interface</title>
<para>The driver interface is implemented in the VirtualBox guest
additions driver (VBoxGuest), which works with the VMM virtual device.
Drivers must use the VBox Guest Library (VBGL), which provides an API
<para><screen>
DECLVBGL(int) VbglHGCMConnect (VBGLHGCMHANDLE *pHandle, VBoxGuestHGCMConnectInfo *pData);
</screen> Connects to the service: <screen>
VBoxGuestHGCMConnectInfo data;
memset (&data, sizeof (VBoxGuestHGCMConnectInfo));
data.result = VINF_SUCCESS;
data.Loc.type = VMMDevHGCMLoc_LocalHost_Existing;
strcpy (data.Loc.u.host.achName, "VBoxSharedFolders");
rc = VbglHGCMConnect (&handle, &data);
if (RT_SUCCESS (rc))
{
rc = data.result;
}
if (RT_SUCCESS (rc))
{
/* Get the assigned client identifier. */
ulClientID = data.u32ClientID;
}
</screen></para>
<para><screen>
DECLVBGL(int) VbglHGCMDisconnect (VBGLHGCMHANDLE handle, VBoxGuestHGCMDisconnectInfo *pData);
</screen> Disconnects from the service. <screen>
VBoxGuestHGCMDisconnectInfo data;
RtlZeroMemory (&data, sizeof (VBoxGuestHGCMDisconnectInfo));
data.result = VINF_SUCCESS;
data.u32ClientID = ulClientID;
rc = VbglHGCMDisconnect (handle, &data);
</screen></para>
<para><screen>
DECLVBGL(int) VbglHGCMCall (VBGLHGCMHANDLE handle, VBoxGuestHGCMCallInfo *pData, uint32_t cbData);
</screen> Calls a function in the service. <screen>
typedef struct _VBoxSFRead
{
VBoxGuestHGCMCallInfo callInfo;
/** pointer, in: SHFLROOT
* Root handle of the mapping which name is queried.
*/
HGCMFunctionParameter root;
/** value64, in:
* SHFLHANDLE of object to read from.
*/
HGCMFunctionParameter handle;
/** value64, in:
* Offset to read from.
*/
HGCMFunctionParameter offset;
*/
HGCMFunctionParameter cb;
/** pointer, out:
* Buffer to place data to.
*/
HGCMFunctionParameter buffer;
} VBoxSFRead;
/** Number of parameters */
#define SHFL_CPARMS_READ (5)
...
VBoxSFRead data;
/* The call information. */
data.callInfo.result = VINF_SUCCESS; /* Will be returned by HGCM. */
data.callInfo.u32ClientID = ulClientID; /* Client identifier. */
data.callInfo.u32Function = SHFL_FN_READ; /* The function code. */
data.callInfo.cParms = SHFL_CPARMS_READ; /* Number of parameters. */
/* Initialize parameters. */
data.root.type = VMMDevHGCMParmType_32bit;
data.root.u.value32 = pMap->root;
data.handle.type = VMMDevHGCMParmType_64bit;
data.handle.u.value64 = hFile;
data.offset.type = VMMDevHGCMParmType_64bit;
data.offset.u.value64 = offset;
data.cb.type = VMMDevHGCMParmType_32bit;
data.cb.u.value32 = *pcbBuffer;
data.buffer.type = VMMDevHGCMParmType_LinAddr_Out;
data.buffer.u.Pointer.size = *pcbBuffer;
data.buffer.u.Pointer.u.linearAddr = (uintptr_t)pBuffer;
rc = VbglHGCMCall (handle, &data.callInfo, sizeof (data));
if (RT_SUCCESS (rc))
{
rc = data.callInfo.result;
*pcbBuffer = data.cb.u.value32; /* This is returned by the HGCM service. */
}
</screen></para>
</sect2>
<sect2>
<title>Guest application interface</title>
<para>Applications call the VirtualBox Guest Additions driver to
utilize the HGCM interface. There are IOCTL's which correspond to the
<computeroutput>Vbgl*</computeroutput> functions: <itemizedlist>
<listitem>
<para><computeroutput>VBOXGUEST_IOCTL_HGCM_CONNECT</computeroutput></para>
</listitem>
<listitem>
<para><computeroutput>VBOXGUEST_IOCTL_HGCM_DISCONNECT</computeroutput></para>
</listitem>
<listitem>
<para><computeroutput>VBOXGUEST_IOCTL_HGCM_CALL</computeroutput></para>
</listitem>
</itemizedlist></para>
<para>These IOCTL's get the same input buffer as
<computeroutput>VbglHGCM*</computeroutput> functions and the output
buffer has the same format as the input buffer. The same address can
be used as the input and output buffers.</para>
<para>For example see the guest part of shared clipboard, which runs
as an application and uses the HGCM interface.</para>
</sect2>
</sect1>
<sect1>
<title>HGCM Service Implementation</title>
<para>The HGCM service is a shared library with a specific set of entry
points. The library must export the
<computeroutput>VBoxHGCMSvcLoad</computeroutput> entry point: <screen>
extern "C" DECLCALLBACK(DECLEXPORT(int)) VBoxHGCMSvcLoad (VBOXHGCMSVCFNTABLE *ptable)
</screen></para>
<para>The service must check the
<computeroutput>ptable->cbSize</computeroutput> and
<computeroutput>ptable->u32Version</computeroutput> fields of the
input structure and fill the remaining fields with function pointers of
entry points and the size of the required client buffer size.</para>
<para>The HGCM service gets a dedicated thread, which calls service
entry points synchronously, that is the service will be called again
only when a previous call has returned. However, the guest calls can be
processed asynchronously. The service must call a completion callback
when the operation is actually completed. The callback can be issued
from another thread as well.</para>
<para>Service entry points are listed in the
<computeroutput>VBOXHGCMSVCFNTABLE</computeroutput> structure. <table>
<title>Service entry points</title>
<tgroup cols="2">
<tbody>
<row>
<entry><emphasis role="bold">Entry</emphasis></entry>
<entry><emphasis role="bold">Description</emphasis></entry>
</row>
<row>
<entry>pfnUnload</entry>
<entry>The service is being unloaded.</entry>
</row>
<row>
<entry>pfnConnect</entry>
<entry>A client <computeroutput>u32ClientID</computeroutput>
is connected to the service. The
<computeroutput>pvClient</computeroutput> parameter points to
an allocated memory buffer which can be used by the service to
store the client information.</entry>
</row>
<row>
<entry>pfnDisconnect</entry>
<entry>A client is being disconnected.</entry>
</row>
<row>
<entry>pfnCall</entry>
<entry>A guest client calls a service function. The
<computeroutput>callHandle</computeroutput> must be used in
the VBOXHGCMSVCHELPERS::pfnCallComplete callback when the call
has been processed.</entry>
</row>
<row>
<entry>pfnHostCall</entry>
<entry>Called by the VirtualBox host components to perform
functions which should be not accessible by the guest. Usually
this entry point is used by VirtualBox to configure the
service.</entry>
</row>
<row>
<entry>pfnSaveState</entry>
<entry>The VM state is being saved and the service must save
relevant information using the SSM API
</row>
<row>
<entry>pfnLoadState</entry>
<entry>The VM is being restored from the saved state and the
service must load the saved information and be able to
continue operations from the saved state.</entry>
</row>
</tbody>
</tgroup>
</table></para>
</sect1>
</chapter>
<chapter id="rdpweb">
<title>RDP Web Control</title>
<para>The VirtualBox <emphasis>RDP Web Control</emphasis> (RDPWeb)
provides remote access to a running VM. RDPWeb is a RDP (Remote Desktop
Protocol) client based on Flash technology and can be used from a Web
browser with a Flash plugin.</para>
<sect1>
<title>RDPWeb features</title>
<para>RDPWeb is embedded into a Web page and can connect to VRDP server
in order to displays the VM screen and pass keyboard and mouse events to
the VM.</para>
</sect1>
<sect1>
<title>RDPWeb reference</title>
<para>RDPWeb consists of two required components:<itemizedlist>
<listitem>
<para>Flash movie
</listitem>
<listitem>
<para>JavaScript helpers
</listitem>
</itemizedlist></para>
<para>The VirtualBox SDK contains sample HTML code
including:<itemizedlist>
<listitem>
<para>JavaScript library for embedding Flash content
</listitem>
<listitem>
<para>Sample HTML page
</listitem>
</itemizedlist></para>
<sect2>
<title>RDPWeb functions</title>
JavaScript code is responsible for a proper SWF initialization,
delivering mouse events to the SWF and processing resize requests from
the SWF. On the other hand, the SWF contains a few JavaScript callable
methods, which are used both from
page.</para>
<sect3>
<title>JavaScript functions</title>
functions. In the following table ElementId refers to an HTML
element name or attribute, and Element to the HTML element itself.
HTML code<programlisting>
<div id="FlashRDP">
</div>
</programlisting> would have ElementId equal to FlashRDP and Element equal to
the div element.</para>
<para><itemizedlist>
<listitem>
<para>Uses SWFObject library to replace the HTML element with
the Flash movie.</para>
</listitem>
<listitem>
<para>Returns true if the given id refers to a RDPWeb Flash
element.</para>
</listitem>
<listitem>
<para>Returns true if the given element is a RDPWeb Flash
element.</para>
</listitem>
<listitem>
<para>Returns an element, which is referenced by the given id.
This function will try to resolve any element, event if it is
not a Flash movie.</para>
</listitem>
</itemizedlist></para>
</sect3>
<sect3>
<title>Flash methods callable from JavaScript</title>
be called directly from JavaScript code on a HTML page.</para>
<itemizedlist>
<listitem>
<para>getProperty(Name)</para>
</listitem>
<listitem>
<para>setProperty(Name)</para>
</listitem>
<listitem>
<para>connect()</para>
</listitem>
<listitem>
<para>disconnect()</para>
</listitem>
<listitem>
<para>keyboardSendCAD()</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Flash JavaScript callbacks</title>
JavaScript functions provided by the HTML page.</para>
</sect3>
</sect2>
<sect2>
<title>Embedding RDPWeb in an HTML page</title>
<para>It is necessary to include
SWFObject library is used, the
and RDPWeb flash content can be embedded to a Web page using dynamic
HTML. The HTML must include a "placeholder", which consists of 2
<computeroutput>div</computeroutput> elements.</para>
</sect2>
</sect1>
<sect1>
<title>RDPWeb change log</title>
<sect2>
<title>Version 1.2.28</title>
<itemizedlist>
<listitem>
<para><computeroutput>keyboardLayout</computeroutput>,
<computeroutput>keyboardLayouts</computeroutput>,
<computeroutput>UUID</computeroutput> properties.</para>
</listitem>
<listitem>
<para>Support for German keyboard layout on the client.</para>
</listitem>
<listitem>
<para>Rebranding to Oracle.</para>
</listitem>
</itemizedlist>
</sect2>
<sect2>
<title>Version 1.1.26</title>
<itemizedlist>
<listitem>
the distribution package.</para>
</listitem>
<listitem>
<para><computeroutput>lastError</computeroutput> property.</para>
</listitem>
<listitem>
<para><computeroutput>keyboardSendScancodes</computeroutput> and
<computeroutput>keyboardSendCAD</computeroutput> methods.</para>
</listitem>
</itemizedlist>
</sect2>
<sect2>
<title>Version 1.0.24</title>
<itemizedlist>
<listitem>
<para>Initial release.</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
</chapter>
<chapter id="vbox-auth">
<title>VirtualBox external authentication modules</title>
<para>VirtualBox supports arbitrary external modules to perform
authentication. The module is used when the authentication method is set
to "external" for a particular VM VRDE access and the library was
specified with <computeroutput>VBoxManage setproperty
vrdeauthlibrary</computeroutput>. Web service also use the authentication
module which was specified with <computeroutput>VBoxManage setproperty
websrvauthlibrary</computeroutput>.</para>
<para>This library will be loaded by the VM or web service process on
demand, i.e. when the first remote desktop connection is made by a client
or when a client that wants to use the web service logs on.</para>
<para>External authentication is the most flexible as the external handler
can both choose to grant access to everyone (like the "null"
authentication method would) and delegate the request to the guest
authentication component. When delegating the request to the guest
component, the handler will still be called afterwards with the option to
override the result.</para>
<para>An authentication library is required to implement exactly one entry
point:</para>
<screen>#include "VBoxAuth.h"
/**
* Authentication library entry point.
*
* Parameters:
*
* szCaller The name of the component which calls the library (UTF8).
* pUuid Pointer to the UUID of the accessed virtual machine. Can be NULL.
* guestJudgement Result of the guest authentication.
* szUser User name passed in by the client (UTF8).
* szPassword Password passed in by the client (UTF8).
* szDomain Domain passed in by the client (UTF8).
* fLogon Boolean flag. Indicates whether the entry point is called
* for a client logon or the client disconnect.
* clientId Server side unique identifier of the client.
*
* Return code:
*
* AuthResultAccessDenied Client access has been denied.
* AuthResultAccessGranted Client has the right to use the
* virtual machine.
* AuthResultDelegateToGuest Guest operating system must
* authenticate the client and the
* library must be called again with
* the result of the guest
* authentication.
*
* Note: When 'fLogon' is 0, only pszCaller, pUuid and clientId are valid and the return
* code is ignored.
*/
AuthResult AUTHCALL AuthEntry(
const char *szCaller,
PAUTHUUID pUuid,
AuthGuestJudgement guestJudgement,
const char *szUser,
const char *szPassword
const char *szDomain
int fLogon,
unsigned clientId)
{
/* Process request against your authentication source of choice. */
// if (authSucceeded(...))
// return AuthResultAccessGranted;
return AuthResultAccessDenied;
}</screen>
<para>A note regarding the UUID implementation of the
<computeroutput>pUuid</computeroutput> argument: VirtualBox uses a
consistent binary representation of UUIDs on all platforms. For this
reason the integer fields comprising the UUID are stored as little endian
values. If you want to pass such UUIDs to code which assumes that the
integer fields are big endian (often also called network byte order), you
need to adjust the contents of the UUID to e.g. achieve the same string
representation. The required changes are:<itemizedlist>
<listitem>
<para>reverse the order of byte 0, 1, 2 and 3</para>
</listitem>
<listitem>
<para>reverse the order of byte 4 and 5</para>
</listitem>
<listitem>
<para>reverse the order of byte 6 and 7.</para>
</listitem>
</itemizedlist>Using this conversion you will get identical results when
converting the binary UUID to the string representation.</para>
<para>The <computeroutput>guestJudgement</computeroutput> argument
contains information about the guest authentication status. For the first
call, it is always set to
<computeroutput>AuthGuestNotAsked</computeroutput>. In case the
<computeroutput>AuthEntry</computeroutput> function returns
<computeroutput>AuthResultDelegateToGuest</computeroutput>, a guest
authentication will be attempted and another call to the
<computeroutput>AuthEntry</computeroutput> is made with its result. This
can be either granted / denied or no judgement (the guest component chose
for whatever reason to not make a decision). In case there is a problem
with the guest authentication module (e.g. the Additions are not installed
or not running or the guest did not respond within a timeout), the "not
reacted" status will be returned.</para>
</chapter>
<chapter id="javaapi">
<title>Using Java API</title>
<sect1>
<title>Introduction</title>
<para>VirtualBox can be controlled by a Java API, both locally
a generic glue layer tries to hide all platform differences, allowing
for source and binary compatibility on different platforms.</para>
</sect1>
<sect1>
<title>Requirements</title>
<para>To use the Java bindings, there are certain requirements depending
on the platform. First of all, you need JDK 1.5 (Java 5) or later. Also
please make sure that the version of the VirtualBox API .jar file
exactly matches the version of VirtualBox you use. To avoid confusion,
the VirtualBox API provides versioning in the Java package name, e.g.
for VirtualBox version 3.2. <itemizedlist>
<listitem>
<para><emphasis role="bold">XPCOM:</emphasis> - for all platforms,
but Microsoft Windows. A Java bridge based on JavaXPCOM is shipped
with VirtualBox. The classpath must contain
location where the VirtualBox binaries are. Please make sure that
the JVM bitness matches bitness of VirtualBox you use as the XPCOM
bridge relies on native libraries.</para>
<para>Start your application like this: <programlisting>
</programlisting></para>
</listitem>
<listitem>
<para><emphasis role="bold">COM:</emphasis> - for Microsoft
Windows. We rely on <computeroutput>Jacob</computeroutput> - a
generic Java to COM bridge - which has to be installed seperately.
See <ulink
url="http://sourceforge.net/projects/jacob-project/">http://sourceforge.net/projects/jacob-project/</ulink>
for installation instructions. Also, the VirtualBox provided
class path.</para>
<para>Start your application like this: <programlisting>
</programlisting></para>
</listitem>
<listitem>
<para><emphasis role="bold">SOAP</emphasis> - all platforms. Java
6 is required, as it comes with builtin support for SOAP via the
JAX-WS library. Also, the VirtualBox provided
path. In the SOAP case it's possible to create several
VirtualBoxManager instances to communicate with multiple
VirtualBox hosts.</para>
<para>Start your application like this: <programlisting>
java -cp vboxjws.jar MyProgram
</programlisting></para>
</listitem>
</itemizedlist></para>
<para>Exception handling is also generalized by the generic glue layer,
so that all methods could throw
<computeroutput>VBoxException</computeroutput> containing human-readable
text message (see <computeroutput>getMessage()</computeroutput> method)
along with wrapped original exception (see
<computeroutput>getWrapped()</computeroutput> method).</para>
</sect1>
<sect1>
<title>Example</title>
<para>This example shows a simple use case of the Java API. Differences
for SOAP vs. local version are minimal, and limited to the connection
setup phase (see <computeroutput>ws</computeroutput> variable). In the
SOAP case it's possible to create several VirtualBoxManager instances to
communicate with multiple VirtualBox hosts. <programlisting>
import org.virtualbox_3_3.*;
....
VirtualBoxManager mgr = VirtualBoxManager.createInstance(null);
boolean ws = false; // or true, if we need the SOAP version
if (ws)
{
String url = "http://myhost:18034";
String user = "test";
String passwd = "test";
mgr.connect(url, user, passwd);
}
IVirtualBox vbox = mgr.getVBox();
System.out.println("VirtualBox version: " + vbox.getVersion() + "\n");
// get first VM name
String m = vbox.getMachines().get(0).getName();
System.out.println("\nAttempting to start VM '" + m + "'");
// start it
mgr.startVm(m, null, 7000);
if (ws)
mgr.cleanup();
</programlisting> For more a complete example, see
SDK.</para>
</sect1>
</chapter>
<chapter>
<title>License information</title>
<para>The sample code files shipped with the SDK are generally licensed
liberally to make it easy for anyone to use this code for their own
application code.</para>
<para>The Java files under
files for the object-oriented web service) are, by contrast, licensed
under the GNU Lesser General Public License (LGPL) V2.1.</para>
<para>See
for the full text of the LGPL 2.1.</para>
<para>When in doubt, please refer to the individual source code files
shipped with this SDK.</para>
</chapter>
<chapter>
<title>Main API change log</title>
<para>Generally, VirtualBox will maintain API compatibility within a major
release; a major release occurs when the first or the second of the three
version components of VirtualBox change (that is, in the x.y.z scheme, a
major release is one where x or y change, but not when only z
changes).</para>
<para>In other words, updates like those from 2.0.0 to 2.0.2 will not come
with API breakages.</para>
<para>Migration between major releases most likely will lead to API
breakage, so please make sure you updated code accordingly. The OOWS Java
wrappers enforce that mechanism by putting VirtualBox classes into
version-specific packages such as
for connecting to multiple VirtualBox versions simultaneously from the
same Java application.</para>
<para>The following sections list incompatible changes that the Main API
underwent since the original release of this SDK Reference with VirtualBox
2.0. A change is deemed "incompatible" only if it breaks existing client
code (e.g. changes in method parameter lists, renamed or removed
interfaces and similar). In other words, the list does not contain new
interfaces, methods or attributes or other changes that do not affect
existing client code.</para>
<sect1>
<title>Incompatible API changes with version 4.2</title>
<itemizedlist>
<listitem>
<para>Guest control APIs for executing guest processes, working with
guest files or directories have been moved to the newly introduced
<xref linkend="IGuestSession" xreflabel="IGuestSession" /> interface which
can be created by calling <xref linkend="IGuest__createSession"
xreflabel="IGuest::createSession()" />.</para>
<para>A guest session will act as a
guest user's impersonation so that the guest credentials only have to
be provided when creating a new guest session. There can be up to 32
guest sessions at once per VM, each session serving up to 2048 guest
processes running or files opened.</para>
<para>Instead of working with process or directory handles before
version 4.2, there now are the dedicated interfaces
<xref linkend="IGuestProcess" xreflabel="IGuestProcess" />,
<xref linkend="IGuestDirectory" xreflabel="IGuestDirectory" /> and
<xref linkend="IGuestFile" xreflabel="IGuestFile" />. To retrieve more
information of a file system object the new interface
<xref linkend="IGuestFsObjInfo" xreflabel="IGuestFsObjInfo" /> has been
introduced.</para>
<para>Even though the guest control API was changed it is backwards
compatible so that it can be used with older installed Guest
Additions. However, to use upcoming features like process termination
or waiting for input / output new Guest Additions must be installed when
these features got implemented.</para>
<para>The following limitations apply:
<itemizedlist>
<listitem><para>The <xref linkend="IGuestFile" xreflabel="IGuestFile" />
interface is not fully implemented yet.</para>
</listitem>
<listitem><para>The symbolic link APIs
<xref linkend="IGuestSession__symlinkCreate"
xreflabel="IGuestSession::symlinkCreate()" />,
<xref linkend="IGuestSession__symlinkExists"
xreflabel="IGuestSession::symlinkExists()" />,
<xref linkend="IGuestSession__symlinkRead"
xreflabel="IGuestSession::symlinkRead()" />,
<xref linkend="IGuestSession__symlinkRemoveDirectory"
xreflabel="IGuestSession::symlinkRemoveDirectory()" /> and
<xref linkend="IGuestSession__symlinkRemoveFile"
xreflabel="IGuestSession::symlinkRemoveFile()" /> are not
implemented yet.</para>
</listitem>
<listitem><para>The directory APIs
<xref linkend="IGuestSession__directoryRemove"
xreflabel="IGuestSession::directoryRemove()" />,
<xref linkend="IGuestSession__directoryRemoveRecursive"
xreflabel="IGuestSession::directoryRemoveRecursive()" />,
<xref linkend="IGuestSession__directoryRename"
xreflabel="IGuestSession::directoryRename()" /> and
<xref linkend="IGuestSession__directorySetACL"
xreflabel="IGuestSession::directorySetACL()" /> are not
implemented yet.</para>
</listitem>
<listitem><para>The temporary file creation API
<xref linkend="IGuestSession__fileCreateTemp"
xreflabel="IGuestSession::fileCreateTemp()" /> is not
implemented yet.</para>
</listitem>
<listitem><para>Guest process termination via
<xref linkend="IProcess__terminate"
xreflabel="IProcess::terminate()" /> is not
implemented yet.</para>
</listitem>
<listitem><para>Waiting for guest process output via
<xref linkend="ProcessWaitForFlag__StdOut" xreflabel="ProcessWaitForFlag::StdOut" />
and <xref linkend="ProcessWaitForFlag__StdErr" xreflabel="ProcessWaitForFlag::StdErr" />
is not implemented yet.</para><para>To wait for process output, <xref linkend="IProcess__read"
xreflabel="IProcess::read()" /> with appropriate flags still can be used to periodically
check for new output data to arrive. Note that <xref linkend="ProcessCreateFlag__WaitForStdOut"
xreflabel="ProcessCreateFlag::WaitForStdOut" /> and / or
<xref linkend="ProcessCreateFlag__WaitForStdErr" xreflabel="ProcessCreateFlag::WaitForStdErr" />
need to be specified when creating a guest process via <xref linkend="IGuestSession__processCreate"
xreflabel="IGuestSession::processCreate()" /> or <xref linkend="IGuestSession__processCreateEx"
xreflabel="IGuestSession::processCreateEx()" />.</para>
</listitem>
<listitem>
<para>ACL (Access Control List) handling in general is not implemented yet.</para>
</listitem>
</itemizedlist>
</para>
</listitem>
<listitem>
<para>The <xref linkend="LockType" xreflabel="LockType" />
enumeration now has an additional value <computeroutput>VM</computeroutput>
which tells <xref linkend="IMachine__lockMachine"
xreflabel="IMachine::lockMachine()" /> to create a full-blown
object structure for running a VM. This was the previous behavior
with <computeroutput>Write</computeroutput>, which now only creates
the minimal object structure to save time and resources (at the
moment the Console object is still created, but all sub-objects
such as Display, Keyboard, Mouse, Guest are not.</para>
</listitem>
<listitem>
<para>Machines can be put in groups (actually an array of groups).
The primary group affects the default placement of files belonging
to a VM. <xref linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine()"/> and
<xref linkend="IVirtualBox__composeMachineFilename"
xreflabel="IVirtualBox::composeMachineFilename()"/> have been
adjusted accordingly, the former taking an array of groups as an
additional parameter and the latter taking a group as an additional
parameter. The create option handling has been changed for those two
methods, too.</para>
</listitem>
<listitem>
<para>The method IVirtualBox::findMedium() has been removed, since
it provides a subset of the functionality of <xref linkend="IVirtualBox__openMedium"
xreflabel="IVirtualBox::openMedium()" />.</para>
</listitem>
<listitem>
<para>The use of acronyms in API enumeration, interface, attribute
and method names has been made much more consistent, previously they
sometimes were lowercase and sometimes mixed case. They are now
consistently all caps:<table>
<title>Renamed identifiers in VirtualBox 4.2</title>
<tgroup cols="2" style="verywide">
<tbody>
<row>
<entry><emphasis role="bold">Old name</emphasis></entry>
<entry><emphasis role="bold">New name</emphasis></entry>
</row>
<row>
<entry>PointingHidType</entry>
<entry><xref linkend="PointingHIDType" xreflabel="PointingHIDType"/></entry>
</row>
<row>
<entry>KeyboardHidType</entry>
<entry><xref linkend="KeyboardHIDType" xreflabel="KeyboardHIDType"/></entry>
</row>
<row>
<entry>IPciAddress</entry>
<entry><xref linkend="IPCIAddress" xreflabel="IPCIAddress"/></entry>
</row>
<row>
<entry>IPciDeviceAttachment</entry>
<entry><xref linkend="IPCIDeviceAttachment" xreflabel="IPCIDeviceAttachment"/></entry>
</row>
<row>
<entry>IMachine::pointingHidType</entry>
<entry><xref linkend="IMachine__pointingHIDType" xreflabel="IMachine::pointingHIDType"/></entry>
</row>
<row>
<entry>IMachine::keyboardHidType</entry>
<entry><xref linkend="IMachine__keyboardHIDType" xreflabel="IMachine::keyboardHIDType"/></entry>
</row>
<row>
<entry>IMachine::hpetEnabled</entry>
<entry><xref linkend="IMachine__HPETEnabled" xreflabel="IMachine::HPETEnabled"/></entry>
</row>
<row>
<entry>IMachine::sessionPid</entry>
<entry><xref linkend="IMachine__sessionPID" xreflabel="IMachine::sessionPID"/></entry>
</row>
<row>
<entry>IMachine::ioCacheEnabled</entry>
<entry><xref linkend="IMachine__IOCacheEnabled" xreflabel="IMachine::IOCacheEnabled"/></entry>
</row>
<row>
<entry>IMachine::ioCacheSize</entry>
<entry><xref linkend="IMachine__IOCacheSize" xreflabel="IMachine::IOCacheSize"/></entry>
</row>
<row>
<entry>IMachine::pciDeviceAssignments</entry>
<entry><xref linkend="IMachine__PCIDeviceAssignments" xreflabel="IMachine::PCIDeviceAssignments"/></entry>
</row>
<row>
<entry>IMachine::attachHostPciDevice()</entry>
<entry><xref linkend="IMachine__attachHostPCIDevice" xreflabel="IMachine::attachHostPCIDevice"/></entry>
</row>
<row>
<entry>IMachine::detachHostPciDevice()</entry>
<entry><xref linkend="IMachine__detachHostPCIDevice" xreflabel="IMachine::detachHostPCIDevice()"/></entry>
</row>
<row>
<entry>IConsole::attachedPciDevices</entry>
<entry><xref linkend="IConsole__attachedPCIDevices" xreflabel="IConsole::attachedPCIDevices"/></entry>
</row>
<row>
<entry>IHostNetworkInterface::dhcpEnabled</entry>
<entry><xref linkend="IHostNetworkInterface__DHCPEnabled" xreflabel="IHostNetworkInterface::DHCPEnabled"/></entry>
</row>
<row>
<entry>IHostNetworkInterface::enableStaticIpConfig()</entry>
<entry><xref linkend="IHostNetworkInterface__enableStaticIPConfig" xreflabel="IHostNetworkInterface::enableStaticIPConfig()"/></entry>
</row>
<row>
<entry>IHostNetworkInterface::enableStaticIpConfigV6()</entry>
<entry><xref linkend="IHostNetworkInterface__enableStaticIPConfigV6" xreflabel="IHostNetworkInterface::enableStaticIPConfigV6()"/></entry>
</row>
<row>
<entry>IHostNetworkInterface::enableDynamicIpConfig()</entry>
<entry><xref linkend="IHostNetworkInterface__enableDynamicIPConfig" xreflabel="IHostNetworkInterface::enableDynamicIPConfig()"/></entry>
</row>
<row>
<entry>IHostNetworkInterface::dhcpRediscover()</entry>
<entry><xref linkend="IHostNetworkInterface__DHCPRediscover" xreflabel="IHostNetworkInterface::DHCPRediscover()"/></entry>
</row>
<row>
<entry>IHost::Acceleration3DAvailable</entry>
<entry><xref linkend="IHost__acceleration3DAvailable" xreflabel="IHost::acceleration3DAvailable"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedPae</entry>
<entry><xref linkend="IGuestOSType__recommendedPAE" xreflabel="IGuestOSType::recommendedPAE"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedDvdStorageController</entry>
<entry><xref linkend="IGuestOSType__recommendedDVDStorageController" xreflabel="IGuestOSType::recommendedDVDStorageController"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedDvdStorageBus</entry>
<entry><xref linkend="IGuestOSType__recommendedDVDStorageBus" xreflabel="IGuestOSType::recommendedDVDStorageBus"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedHdStorageController</entry>
<entry><xref linkend="IGuestOSType__recommendedHDStorageController" xreflabel="IGuestOSType::recommendedHDStorageController"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedHdStorageBus</entry>
<entry><xref linkend="IGuestOSType__recommendedHDStorageBus" xreflabel="IGuestOSType::recommendedHDStorageBus"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedUsbHid</entry>
<entry><xref linkend="IGuestOSType__recommendedUSBHID" xreflabel="IGuestOSType::recommendedUSBHID"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedHpet</entry>
<entry><xref linkend="IGuestOSType__recommendedHPET" xreflabel="IGuestOSType::recommendedHPET"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedUsbTablet</entry>
<entry><xref linkend="IGuestOSType__recommendedUSBTablet" xreflabel="IGuestOSType::recommendedUSBTablet"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedRtcUseUtc</entry>
<entry><xref linkend="IGuestOSType__recommendedRTCUseUTC" xreflabel="IGuestOSType::recommendedRTCUseUTC"/></entry>
</row>
<row>
<entry>IGuestOSType::recommendedUsb</entry>
<entry><xref linkend="IGuestOSType__recommendedUSB" xreflabel="IGuestOSType::recommendedUSB"/></entry>
</row>
<row>
<entry>INetworkAdapter::natDriver</entry>
<entry><xref linkend="INetworkAdapter__NATEngine" xreflabel="INetworkAdapter::NATEngine"/></entry>
</row>
<row>
<entry>IUSBController::enabledEhci</entry>
<entry><xref linkend="IUSBController__enabledEHCI" xreflabel="IUSBController::enabledEHCI"/></entry>
</row>
<row>
<entry>INATEngine::tftpPrefix</entry>
<entry><xref linkend="INATEngine__TFTPPrefix" xreflabel="INATEngine::TFTPPrefix"/></entry>
</row>
<row>
<entry>INATEngine::tftpBootFile</entry>
<entry><xref linkend="INATEngine__TFTPBootFile" xreflabel="INATEngine::TFTPBootFile"/></entry>
</row>
<row>
<entry>INATEngine::tftpNextServer</entry>
<entry><xref linkend="INATEngine__TFTPNextServer" xreflabel="INATEngine::TFTPNextServer"/></entry>
</row>
<row>
<entry>INATEngine::dnsPassDomain</entry>
<entry><xref linkend="INATEngine__DNSPassDomain" xreflabel="INATEngine::DNSPassDomain"/></entry>
</row>
<row>
<entry>INATEngine::dnsProxy</entry>
<entry><xref linkend="INATEngine__DNSProxy" xreflabel="INATEngine::DNSProxy"/></entry>
</row>
<row>
<entry>INATEngine::dnsUseHostResolver</entry>
<entry><xref linkend="INATEngine__DNSUseHostResolver" xreflabel="INATEngine::DNSUseHostResolver"/></entry>
</row>
<row>
<entry>VBoxEventType::OnHostPciDevicePlug</entry>
<entry><xref linkend="VBoxEventType__OnHostPCIDevicePlug" xreflabel="VBoxEventType::OnHostPCIDevicePlug"/></entry>
</row>
<row>
<entry>ICPUChangedEvent::cpu</entry>
<entry><xref linkend="ICPUChangedEvent__CPU" xreflabel="ICPUChangedEvent::CPU"/></entry>
</row>
<row>
<entry>INATRedirectEvent::hostIp</entry>
<entry><xref linkend="INATRedirectEvent__hostIP" xreflabel="INATRedirectEvent::hostIP"/></entry>
</row>
<row>
<entry>INATRedirectEvent::guestIp</entry>
<entry><xref linkend="INATRedirectEvent__guestIP" xreflabel="INATRedirectEvent::guestIP"/></entry>
</row>
<row>
<entry>IHostPciDevicePlugEvent</entry>
<entry><xref linkend="IHostPCIDevicePlugEvent" xreflabel="IHostPCIDevicePlugEvent"/></entry>
</row>
</tbody>
</tgroup></table></para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 4.1</title>
<itemizedlist>
<listitem>
<para>The method <xref linkend="IAppliance__importMachines"
xreflabel="IAppliance::importMachines()" /> has one more parameter
now, which allows to configure the import process in more detail.
</para>
</listitem>
<listitem>
<para>The method <xref linkend="IVirtualBox__openMedium"
xreflabel="IVirtualBox::openMedium()" /> has one more parameter
now, which allows resolving duplicate medium UUIDs without the need
for external tools.</para>
</listitem>
<listitem>
<para>The <xref linkend="INetworkAdapter" xreflabel="INetworkAdapter"/>
interface has been cleaned up. The various methods to activate an
attachment type have been replaced by the
<xref linkend="INetworkAdapter__attachmentType" xreflabel="INetworkAdapter::attachmentType"/> setter.</para>
<para>Additionally each attachment mode now has its own attribute,
which means that host only networks no longer share the settings with
bridged interfaces.</para>
<para>To allow introducing new network attachment implementations
without making API changes, the concept of a generic network
attachment driver has been introduced, which is configurable through
</listitem>
<listitem>
<para>This version introduces the guest facilities concept. A guest
facility either represents a module or feature the guest is running or
offering, which is defined by <xref linkend="AdditionsFacilityType"
xreflabel="AdditionsFacilityType"/>. Each facility is member of a
<xref linkend="AdditionsFacilityClass" xreflabel="AdditionsFacilityClass"/>
and has a current status indicated by <xref linkend="AdditionsFacilityStatus"
xreflabel="AdditionsFacilityStatus"/>, together with a timestamp (in ms) of
the last status update.</para>
<para>To address the above concept, the following changes were made:
<itemizedlist>
<listitem>
<para>
In the <xref linkend="IGuest" xreflabel="IGuest"/> interface, the following were removed:
<itemizedlist>
<listitem>
<para>the <computeroutput>supportsSeamless</computeroutput> attribute;</para>
</listitem>
<listitem>
<para>the <computeroutput>supportsGraphics</computeroutput> attribute;</para>
</listitem>
</itemizedlist>
</para>
</listitem>
<listitem>
<para>
The function <xref linkend="IGuest__getFacilityStatus" xreflabel="IGuest::getFacilityStatus()"/>
was added. It quickly provides a facility's status without the need to get the facility
collection with <xref linkend="IGuest__facilities" xreflabel="IGuest::facilities"/>.
</para>
</listitem>
<listitem>
<para>
The attribute <xref linkend="IGuest__facilities" xreflabel="IGuest::facilities"/>
was added to provide an easy to access collection of all currently known guest
facilities, that is, it contains all facilies where at least one status update was
made since the guest was started.
</para>
</listitem>
<listitem>
<para>
The interface <xref linkend="IAdditionsFacility" xreflabel="IAdditionsFacility"/>
was added to represent a single facility returned by
<xref linkend="IGuest__facilities" xreflabel="IGuest::facilities"/>.
</para>
</listitem>
<listitem>
<para>
<xref linkend="AdditionsFacilityStatus" xreflabel="AdditionsFacilityStatus"/>
was added to represent a facility's overall status.
</para>
</listitem>
<listitem>
<para>
<xref linkend="AdditionsFacilityType" xreflabel="AdditionsFacilityType"/> and
<xref linkend="AdditionsFacilityClass" xreflabel="AdditionsFacilityClass"/> were
added to represent the facility's type and class.
</para>
</listitem>
</itemizedlist>
</para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 4.0</title>
<itemizedlist>
<listitem>
<para>A new Java glue layer replacing the previous OOWS JAX-WS
bindings was introduced. The new library allows for uniform code
instead of <computeroutput>IWebsessionManager</computeroutput>, the
new class <computeroutput>VirtualBoxManager</computeroutput> must be
used. See <xref linkend="javaapi" xreflabel="Java API chapter" />
for details.</para>
</listitem>
<listitem>
<para>The confusingly named and impractical session APIs were
changed. In existing client code, the following changes need to be
made:<itemizedlist>
<listitem>
<para>Replace any
<computeroutput>IVirtualBox::openSession(uuidMachine,
...)</computeroutput> API call with the machine's <xref
linkend="IMachine__lockMachine"
xreflabel="IMachine::lockMachine()" /> call and a
functionality is unchanged, but instead of "opening a direct
session on a machine" all documentation now refers to
"obtaining a write lock on a machine for the client
session".</para>
</listitem>
<listitem>
<para>Similarly, replace any
<computeroutput>IVirtualBox::openExistingSession(uuidMachine,
...)</computeroutput> call with the machine's <xref
linkend="IMachine__lockMachine"
xreflabel="IMachine::lockMachine()" /> call and a
Whereas it was previously impossible to connect a client
session to a running VM process in a race-free manner, the new
API will atomically either write-lock the machine for the
current session or establish a remote link to an existing
session. Existing client code which tried calling both
<computeroutput>openSession()</computeroutput> and
<computeroutput>openExistingSession()</computeroutput> can now
use this one call instead.</para>
</listitem>
<listitem>
<para>Third, replace any
<computeroutput>IVirtualBox::openRemoteSession(uuidMachine,
...)</computeroutput> call with the machine's <xref
linkend="IMachine__launchVMProcess"
xreflabel="IMachine::launchVMProcess()" /> call. The
functionality is unchanged.</para>
</listitem>
<listitem>
<para>The <xref linkend="SessionState"
xreflabel="SessionState" /> enum was adjusted accordingly:
"Open" is now "Locked", "Closed" is now "Unlocked", "Closing"
is now "Unlocking".</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>Virtual machines created with VirtualBox 4.0 or later no
longer register their media in the global media registry in the
machines list all their media in their own machine XML files. As a
result, a number of media-related APIs had to be modified again.
<itemizedlist>
<listitem>
<para>Neither <xref linkend="IVirtualBox__createHardDisk"
xreflabel="IVirtualBox::createHardDisk()" /> nor <xref
linkend="IVirtualBox__openMedium"
xreflabel="IVirtualBox::openMedium()" /> register media
automatically any more.</para>
</listitem>
<listitem>
<para><xref linkend="IMachine__attachDevice"
xreflabel="IMachine::attachDevice()" /> and <xref
linkend="IMachine__mountMedium"
xreflabel="IMachine::mountMedium()" /> now take an IMedium
object instead of a UUID as an argument. It is these two calls
which add media to a registry now (either a machine registry
for machines created with VirtualBox 4.0 or later or the
global registry otherwise). As a consequence, if a medium is
opened but never attached to a machine, it is no longer added
to any registry any more.</para>
</listitem>
<listitem>
<para>To reduce code duplication, the APIs
IVirtualBox::findHardDisk(), getHardDisk(), findDVDImage(),
getDVDImage(), findFloppyImage() and getFloppyImage() have all
been merged into IVirtualBox::findMedium(), and
IVirtualBox::openHardDisk(), openDVDImage() and
openFloppyImage() have all been merged into <xref
linkend="IVirtualBox__openMedium"
xreflabel="IVirtualBox::openMedium()" />.</para>
</listitem>
<listitem>
<para>The rare use case of changing the UUID and parent UUID
of a medium previously handled by
<computeroutput>openHardDisk()</computeroutput> is now in a
separate IMedium::setIDs method.</para>
</listitem>
<listitem>
have been removed since disk images are now by default placed
in each machine's folder.</para>
</listitem>
<listitem>
<para>The <xref linkend="ISystemProperties__infoVDSize"
xreflabel="ISystemProperties::infoVDSize" /> attribute
replaces the <computeroutput>getMaxVDISize()</computeroutput>
API call; this now uses bytes instead of megabytes.</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>Machine management APIs were enhanced as follows:<itemizedlist>
<listitem>
<para><xref linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine()" /> is no longer
restricted to creating machines in the default "Machines"
folder, but can now create machines at arbitrary locations.
For this to work, the parameter list had to be changed.</para>
</listitem>
<listitem>
<para>The long-deprecated
<computeroutput>IVirtualBox::createLegacyMachine()</computeroutput>
API has been removed.</para>
</listitem>
<listitem>
<para>To reduce code duplication and for consistency with the
aforementioned media APIs,
<computeroutput>IVirtualBox::getMachine()</computeroutput> has
been merged with <xref linkend="IVirtualBox__findMachine"
xreflabel="IVirtualBox::findMachine()" />, and
<computeroutput>IMachine::getSnapshot()</computeroutput> has
been merged with <xref linkend="IMachine__findSnapshot"
xreflabel="IMachine::findSnapshot()" />.</para>
</listitem>
<listitem>
<para><computeroutput>IVirtualBox::unregisterMachine()</computeroutput>
was replaced with <xref linkend="IMachine__unregister"
xreflabel="IMachine::unregister()" /> with additional
functionality for cleaning up machine files.</para>
</listitem>
<listitem>
<para><computeroutput>IConsole::forgetSavedState</computeroutput>
has been renamed to <xref
linkend="IConsole__discardSavedState"
xreflabel="IConsole::discardSavedState()" />.</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>All event callbacks APIs were replaced with a new, generic
event mechanism that can be used both locally (COM, XPCOM) and
remotely (web services). Also, the new mechanism is usable from
scripting languages and a local Java. See <xref linkend="IEvent"
xreflabel="events" /> for details. The new concept will require
changes to all clients that used event callbacks.</para>
</listitem>
<listitem>
<para><computeroutput>additionsActive()</computeroutput> was
replaced with <xref linkend="IGuest__additionsRunLevel"
xreflabel="additionsRunLevel()" /> and <xref
linkend="IGuest__getAdditionsStatus"
xreflabel="getAdditionsStatus()" /> in order to support a more
state. <xref linkend="IGuest__additionsVersion"
xreflabel="IGuest::additionsVersion()" /> no longer returns the
Guest Additions interface version but the installed Guest Additions
version and revision in form of
<computeroutput>3.3.0r12345</computeroutput>.</para>
</listitem>
<listitem>
<para>To address shared folders auto-mounting support, the following
APIs were extended to require an additional
<computeroutput>automount</computeroutput> parameter: <itemizedlist>
<listitem>
<para><xref linkend="IVirtualBox__createSharedFolder"
xreflabel="IVirtualBox::createSharedFolder()" /></para>
</listitem>
<listitem>
<para><xref linkend="IMachine__createSharedFolder"
xreflabel="IMachine::createSharedFolder()" /></para>
</listitem>
<listitem>
<para><xref linkend="IConsole__createSharedFolder"
xreflabel="IConsole::createSharedFolder()" /></para>
</listitem>
</itemizedlist> Also, a new property named
<computeroutput>autoMount</computeroutput> was added to the <xref
linkend="ISharedFolder" xreflabel="ISharedFolder" />
interface.</para>
</listitem>
<listitem>
<para>The appliance (OVF) APIs were enhanced as
follows:<itemizedlist>
<listitem>
<para><xref linkend="IMachine__export"
xreflabel="IMachine::export()" /> received an extra parameter
<computeroutput>location</computeroutput>, which is used to
decide for the disk naming.</para>
</listitem>
<listitem>
<para><xref linkend="IAppliance__write"
xreflabel="IAppliance::write()" /> received an extra parameter
<computeroutput>manifest</computeroutput>, which can suppress
creating the manifest file on export.</para>
</listitem>
<listitem>
<para><xref linkend="IVFSExplorer__entryList"
xreflabel="IVFSExplorer::entryList()" /> received two extra
parameters <computeroutput>sizes</computeroutput> and
<computeroutput>modes</computeroutput>, which contains the
sizes (in bytes) and the file access modes (in octal form) of
the returned files.</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>Support for remote desktop access to virtual machines has been
cleaned up to allow third party implementations of the remote
desktop server. This is called the VirtualBox Remote Desktop
Extension (VRDE) and can be added to VirtualBox by installing the
corresponding extension package; see the VirtualBox User Manual for
details.</para>
<para>The following API changes were made to support the VRDE
interface: <itemizedlist>
<listitem>
<para><computeroutput>IVRDPServer</computeroutput> has been
renamed to <xref linkend="IVRDEServer"
xreflabel="IVRDEServer" />.</para>
</listitem>
<listitem>
<para><computeroutput>IRemoteDisplayInfo</computeroutput> has
been renamed to <xref linkend="IVRDEServerInfo"
xreflabel="IVRDEServerInfo" />.</para>
</listitem>
<listitem>
<para><xref linkend="IMachine__VRDEServer"
xreflabel="IMachine::VRDEServer" /> replaces
<computeroutput>VRDPServer.</computeroutput></para>
</listitem>
<listitem>
<para><xref linkend="IConsole__VRDEServerInfo"
xreflabel="IConsole::VRDEServerInfo" /> replaces
<computeroutput>RemoteDisplayInfo</computeroutput>.</para>
</listitem>
<listitem>
<para><xref linkend="ISystemProperties__VRDEAuthLibrary"
xreflabel="ISystemProperties::VRDEAuthLibrary" /> replaces
<computeroutput>RemoteDisplayAuthLibrary</computeroutput>.</para>
</listitem>
<listitem>
<para>The following methods have been implemented in
<computeroutput>IVRDEServer</computeroutput> to support
generic VRDE properties: <itemizedlist>
<listitem>
<para><xref linkend="IVRDEServer__setVRDEProperty"
xreflabel="IVRDEServer::setVRDEProperty" /></para>
</listitem>
<listitem>
<para><xref linkend="IVRDEServer__getVRDEProperty"
xreflabel="IVRDEServer::getVRDEProperty" /></para>
</listitem>
<listitem>
<para><xref linkend="IVRDEServer__VRDEProperties"
xreflabel="IVRDEServer::VRDEProperties" /></para>
</listitem>
</itemizedlist></para>
<para>A few implementation-specific attributes of the old
<computeroutput>IVRDPServer</computeroutput> interface have
been removed and replaced with properties: <itemizedlist>
<listitem>
<para><computeroutput>IVRDPServer::Ports</computeroutput>
has been replaced with the
The property value is a string, which contains a
comma-separated list of ports or ranges of ports. Use a
dash between two port numbers to specify a range.
Example:
<computeroutput>"5000,5010-5012"</computeroutput></para>
</listitem>
<listitem>
<para><computeroutput>IVRDPServer::NetAddress</computeroutput>
has been replaced with the
The property value is an IP address string. Example:
<computeroutput>"127.0.0.1"</computeroutput></para>
</listitem>
<listitem>
<para><computeroutput>IVRDPServer::VideoChannel</computeroutput>
has been replaced with the
property. The property value is either
<computeroutput>"true"</computeroutput> or
<computeroutput>"false"</computeroutput></para>
</listitem>
<listitem>
<para><computeroutput>IVRDPServer::VideoChannelQuality</computeroutput>
has been replaced with the
property. The property value is a string which contain a
decimal number in range 10..100. Invalid values are
ignored and the quality is set to the default value 75.
Example: <computeroutput>"50"</computeroutput></para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>The VirtualBox external authentication module interface has
been updated and made more generic. Because of that,
<computeroutput>VRDPAuthType</computeroutput> enumeration has been
renamed to <xref linkend="AuthType" xreflabel="AuthType" />.</para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 3.2</title>
<itemizedlist>
<listitem>
<para>The following interfaces were renamed for consistency:
<itemizedlist>
<listitem>
<para>IMachine::getCpuProperty() is now <xref
linkend="IMachine__getCPUProperty"
xreflabel="IMachine::getCPUProperty()" />;</para>
</listitem>
<listitem>
<para>IMachine::setCpuProperty() is now <xref
linkend="IMachine__setCPUProperty"
xreflabel="IMachine::setCPUProperty()" />;</para>
</listitem>
<listitem>
<para>IMachine::getCpuIdLeaf() is now <xref
linkend="IMachine__getCPUIDLeaf"
xreflabel="IMachine::getCPUIDLeaf()" />;</para>
</listitem>
<listitem>
<para>IMachine::setCpuIdLeaf() is now <xref
linkend="IMachine__setCPUIDLeaf"
xreflabel="IMachine::setCPUIDLeaf()" />;</para>
</listitem>
<listitem>
<para>IMachine::removeCpuIdLeaf() is now <xref
linkend="IMachine__removeCPUIDLeaf"
xreflabel="IMachine::removeCPUIDLeaf()" />;</para>
</listitem>
<listitem>
<para>IMachine::removeAllCpuIdLeafs() is now <xref
linkend="IMachine__removeAllCPUIDLeaves"
xreflabel="IMachine::removeAllCPUIDLeaves()" />;</para>
</listitem>
<listitem>
<para>the CpuPropertyType enum is now <xref
linkend="CPUPropertyType"
xreflabel="CPUPropertyType" />.</para>
</listitem>
<listitem>
<para>IVirtualBoxCallback::onSnapshotDiscarded() is now
IVirtualBoxCallback::onSnapshotDeleted.</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>When creating a VM configuration with <xref
linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine" />) it is now possible to
ignore existing configuration files which would previously have
caused a failure. For this the
<computeroutput>override</computeroutput> parameter was
added.</para>
</listitem>
<listitem>
<para>Deleting snapshots via <xref
linkend="IConsole__deleteSnapshot"
xreflabel="IConsole::deleteSnapshot()" /> is now possible while the
associated VM is running in almost all cases. The API is unchanged,
but client code that verifies machine states to determine whether
snapshots can be deleted may need to be adjusted.</para>
</listitem>
<listitem>
<para>The IoBackendType enumeration was replaced with a boolean flag
(see <xref linkend="IStorageController__useHostIOCache"
xreflabel="IStorageController::useHostIOCache" />).</para>
</listitem>
<listitem>
<para>To address multi-monitor support, the following APIs were
extended to require an additional
<computeroutput>screenId</computeroutput> parameter: <itemizedlist>
<listitem>
<para><xref linkend="IMachine__querySavedThumbnailSize"
xreflabel="IMachine::querySavedThumbnailSize()" /></para>
</listitem>
<listitem>
<para><xref linkend="IMachine__readSavedThumbnailToArray"
xreflabel="IMachine::readSavedThumbnailToArray()" /></para>
</listitem>
<listitem>
<para><xref linkend="IMachine__querySavedScreenshotPNGSize"
xreflabel="IMachine::querySavedScreenshotPNGSize()" /></para>
</listitem>
<listitem>
<para><xref linkend="IMachine__readSavedScreenshotPNGToArray"
xreflabel="IMachine::readSavedScreenshotPNGToArray()" /></para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>The <computeroutput>shape</computeroutput> parameter of
IConsoleCallback::onMousePointerShapeChange was changed from a
implementation-specific pointer to a safearray, enabling scripting
languages to process pointer shapes.</para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 3.1</title>
<itemizedlist>
<listitem>
<para>Due to the new flexibility in medium attachments that was
introduced with version 3.1 (in particular, full flexibility with
opportunity to rework all interfaces dealing with storage media to
make the API more flexible as well as logical. The <xref
linkend="IStorageController" xreflabel="IStorageController" />,
<xref linkend="IMedium" xreflabel="IMedium" />, <xref
linkend="IMediumAttachment" xreflabel="IMediumAttachment" /> and,
<xref linkend="IMachine" xreflabel="IMachine" /> interfaces were
affected the most. Existing code using them to configure storage and
media needs to be carefully checked.</para>
uniformly handled through the <xref linkend="IMedium"
xreflabel="IMedium" /> interface. The device-specific interfaces
(<code>IHardDisk</code>, <code>IDVDImage</code>,
<code>IHostDVDDrive</code>, <code>IFloppyImage</code> and
and floppy media no longer need special treatment. The device type
of a medium determines in which context it can be used. Some
functionality was moved to the other storage-related
interfaces.</para>
<para><code>IMachine::attachHardDisk</code> and similar methods have
been renamed and generalized to deal with any type of drive and
medium. <xref linkend="IMachine__attachDevice"
xreflabel="IMachine::attachDevice()" /> is the API method for adding
no longer handled specially, and that means you can have more than
one of them. As before, drives can only be changed while the VM is
powered off. Mounting (or unmounting) removable media at runtime is
possible with <xref linkend="IMachine__mountMedium"
xreflabel="IMachine::mountMedium()" />.</para>
<para>Newly created virtual machines have no storage controllers
associated with them. Even the IDE Controller needs to be created
explicitly. The floppy controller is now visible as a separate
controller, with a new storage bus type. For each storage bus type
you can query the device types which can be attached, so that it is
not necessary to hardcode any attachment rules.</para>
<para>This required matching changes e.g. in the callback interfaces
(the medium specific change notification was replaced by a generic
medium change notification) and removing associated enums (e.g.
<code>DriveState</code>). In many places the incorrect use of the
plural form "media" was replaced by "medium", to improve
consistency.</para>
</listitem>
<listitem>
<para>Reading the <xref linkend="IMedium__state"
xreflabel="IMedium::state" xrefstyle="" /> attribute no longer
automatically performs an accessibility check; a new method <xref
linkend="IMedium__refreshState"
xreflabel="IMedium::refreshState()" /> does this. The attribute only
returns the state any more.</para>
</listitem>
<listitem>
<para>There were substantial changes related to snapshots, triggered
by the "branched snapshots" functionality introduced with version
3.1. IConsole::discardSnapshot was renamed to <xref
linkend="IConsole__deleteSnapshot"
xreflabel="IConsole::deleteSnapshot()" />.
IConsole::discardCurrentState and
IConsole::discardCurrentSnapshotAndState were removed; corresponding
new functionality is in <xref linkend="IConsole__restoreSnapshot"
xreflabel="IConsole::restoreSnapshot()" />. Also, when <xref
linkend="IConsole__takeSnapshot"
xreflabel="IConsole::takeSnapshot()" /> is called on a running
virtual machine, a live snapshot will be created. The old behavior
was to temporarily pause the virtual machine while creating an
online snapshot.</para>
</listitem>
<listitem>
<para>The <computeroutput>IVRDPServer</computeroutput>,
<computeroutput>IRemoteDisplayInfo"</computeroutput> and
<computeroutput>IConsoleCallback</computeroutput> interfaces were
changed to reflect VRDP server ability to bind to one of available
ports from a list of ports.</para>
<para>The <computeroutput>IVRDPServer::port</computeroutput>
attribute has been replaced with
<computeroutput>IVRDPServer::ports</computeroutput>, which is a
comma-separated list of ports or ranges of ports.</para>
<para>An <computeroutput>IRemoteDisplayInfo::port"</computeroutput>
attribute has been added for querying the actual port VRDP server
listens on.</para>
<para>An IConsoleCallback::onRemoteDisplayInfoChange() notification
callback has been added.</para>
</listitem>
<listitem>
<para>The parameter lists for the following functions were
modified:<itemizedlist>
<listitem>
<para><xref linkend="IHost__removeHostOnlyNetworkInterface"
xreflabel="IHost::removeHostOnlyNetworkInterface()" /></para>
</listitem>
<listitem>
<para><xref linkend="IHost__removeUSBDeviceFilter"
xreflabel="IHost::removeUSBDeviceFilter()" /></para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>In the OOWS bindings for JAX-WS, the behavior of structures
changed: for one, we implemented natural structures field access so
you can just call a "get" method to obtain a field. Secondly,
setters in structures were disabled as they have no expected effect
and were at best misleading.</para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 3.0</title>
<itemizedlist>
<listitem>
<para>In the object-oriented web service bindings for JAX-WS, proper
inheritance has been introduced for some classes, so explicit
casting is no longer needed to call methods from a parent class. In
particular, IHardDisk and other classes now properly derive from
<xref linkend="IMedium" xreflabel="IMedium" />.</para>
</listitem>
<listitem>
<para>All object identifiers (machines, snapshots, disks, etc)
switched from GUIDs to strings (now still having string
representation of GUIDs inside). As a result, no particular internal
structure can be assumed for object identifiers; instead, they
should be treated as opaque unique handles. This change mostly
affects Java and C++ programs; for other languages, GUIDs are
transparently converted to strings.</para>
</listitem>
<listitem>
<para>The uses of NULL strings have been changed greatly. All out
parameters now use empty strings to signal a null value. For in
parameters both the old NULL and empty string is allowed. This
change was necessary to support more client bindings, especially
using the web service API. Many of them either have no special NULL
value or have trouble dealing with it correctly in the respective
library code.</para>
</listitem>
<listitem>
<para>Accidentally, the <code>TSBool</code> interface still appeared
in 3.0.0, and was removed in 3.0.2. This is an SDK bug, do not use
the SDK for VirtualBox 3.0.0 for developing clients.</para>
</listitem>
<listitem>
<para>The type of <xref linkend="IVirtualBoxErrorInfo__resultCode"
xreflabel="IVirtualBoxErrorInfo::resultCode" /> changed from
<computeroutput>result</computeroutput> to
<computeroutput>long</computeroutput>.</para>
</listitem>
<listitem>
<para>The parameter list of IVirtualBox::openHardDisk was
changed.</para>
</listitem>
<listitem>
<para>The method IConsole::discardSavedState was renamed to
IConsole::forgetSavedState, and a parameter was added.</para>
</listitem>
<listitem>
<para>The method IConsole::powerDownAsync was renamed to <xref
linkend="IConsole__powerDown" xreflabel="IConsole::powerDown" />,
and the previous method with that name was deleted. So effectively a
parameter was added.</para>
</listitem>
<listitem>
<para>In the <xref linkend="IFramebuffer"
xreflabel="IFramebuffer" /> interface, the following were
removed:<itemizedlist>
<listitem>
<para>the <computeroutput>operationSupported</computeroutput>
attribute;</para>
<para>(as a result, the
<computeroutput>FramebufferAccelerationOperation</computeroutput>
enum was no longer needed and removed as well);</para>
</listitem>
<listitem>
<para>the <computeroutput>solidFill()</computeroutput>
method;</para>
</listitem>
<listitem>
<para>the <computeroutput>copyScreenBits()</computeroutput>
method.</para>
</listitem>
</itemizedlist></para>
</listitem>
<listitem>
<para>In the <xref linkend="IDisplay" xreflabel="IDisplay" />
interface, the following were removed:<itemizedlist>
<listitem>
<para>the
<computeroutput>setupInternalFramebuffer()</computeroutput>
method;</para>
</listitem>
<listitem>
<para>the <computeroutput>lockFramebuffer()</computeroutput>
method;</para>
</listitem>
<listitem>
<para>the <computeroutput>unlockFramebuffer()</computeroutput>
method;</para>
</listitem>
<listitem>
<para>the
<computeroutput>registerExternalFramebuffer()</computeroutput>
method.</para>
</listitem>
</itemizedlist></para>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 2.2</title>
<itemizedlist>
<listitem>
<para>Added explicit version number into JAX-WS Java package names,
allowing connect to multiple VirtualBox clients from single Java
application.</para>
</listitem>
<listitem>
<para>The interfaces having a "2" suffix attached to them with
version 2.1 were renamed again to have that suffix removed. This
time around, this change involves only the name, there are no
functional differences.</para>
<para>As a result, IDVDImage2 is now IDVDImage; IHardDisk2 is now
IHardDisk; IHardDisk2Attachment is now IHardDiskAttachment.</para>
<para>Consequentially, all related methods and attributes that had a
"2" suffix have been renamed; for example, IMachine::attachHardDisk2
now becomes IMachine::attachHardDisk().</para>
</listitem>
<listitem>
<para>IVirtualBox::openHardDisk has an extra parameter for opening a
</listitem>
<listitem>
<para>The remaining collections were replaced by more performant
safe-arrays. This affects the following collections:</para>
<itemizedlist>
<listitem>
<para>IGuestOSTypeCollection</para>
</listitem>
<listitem>
<para>IHostDVDDriveCollection</para>
</listitem>
<listitem>
<para>IHostFloppyDriveCollection</para>
</listitem>
<listitem>
<para>IHostUSBDeviceCollection</para>
</listitem>
<listitem>
<para>IHostUSBDeviceFilterCollection</para>
</listitem>
<listitem>
<para>IProgressCollection</para>
</listitem>
<listitem>
<para>ISharedFolderCollection</para>
</listitem>
<listitem>
<para>ISnapshotCollection</para>
</listitem>
<listitem>
<para>IUSBDeviceCollection</para>
</listitem>
<listitem>
<para>IUSBDeviceFilterCollection</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>Since "Host Interface Networking" was renamed to "bridged
networking" and host-only networking was introduced, all associated
interfaces needed renaming as well. In detail:</para>
<itemizedlist>
<listitem>
<para>The HostNetworkInterfaceType enum has been renamed to
<xref linkend="HostNetworkInterfaceMediumType"
xreflabel="HostNetworkInterfaceMediumType" /></para>
</listitem>
<listitem>
<para>The IHostNetworkInterface::type attribute has been renamed
to <xref linkend="IHostNetworkInterface__mediumType"
xreflabel="IHostNetworkInterface::mediumType" /></para>
</listitem>
<listitem>
<para>INetworkAdapter::attachToHostInterface() has been renamed
to INetworkAdapter::attachToBridgedInterface</para>
</listitem>
<listitem>
<para>In the IHost interface, createHostNetworkInterface() has
been renamed to <xref
linkend="IHost__createHostOnlyNetworkInterface"
xreflabel="createHostOnlyNetworkInterface()" /></para>
</listitem>
<listitem>
<para>Similarly, removeHostNetworkInterface() has been renamed
to <xref linkend="IHost__removeHostOnlyNetworkInterface"
xreflabel="removeHostOnlyNetworkInterface()" /></para>
</listitem>
</itemizedlist>
</listitem>
</itemizedlist>
</sect1>
<sect1>
<title>Incompatible API changes with version 2.1</title>
<itemizedlist>
<listitem>
<para>With VirtualBox 2.1, error codes were added to many error
infos that give the caller a machine-readable (numeric) feedback in
addition to the error string that has always been available. This is
an ongoing process, and future versions of this SDK reference will
document the error codes for each method call.</para>
</listitem>
<listitem>
<para>The hard disk and other media interfaces were completely
redesigned. This was necessary to account for the support of VMDK,
VHD and other image types; since backwards compatibility had to be
broken anyway, we seized the moment to redesign the interfaces in a
more logical way.</para>
<itemizedlist>
<listitem>
<para>Previously, the old IHardDisk interface had several
derivatives called IVirtualDiskImage, IVMDKImage, IVHDImage,
IISCSIHardDisk and ICustomHardDisk for the various disk formats
supported by VirtualBox. The new IHardDisk2 interface that comes
with version 2.1 now supports all hard disk image formats
itself.</para>
</listitem>
<listitem>
<para>IHardDiskFormat is a new interface to describe the
available back-ends for hard disk images (e.g. VDI, VMDK, VHD or
iSCSI). The IHardDisk2::format attribute can be used to find out
the back-end that is in use for a particular hard disk image.
ISystemProperties::hardDiskFormats[] contains a list of all
back-ends supported by the system. <xref
linkend="ISystemProperties__defaultHardDiskFormat"
xreflabel="ISystemProperties::defaultHardDiskFormat" /> contains
the default system format.</para>
</listitem>
<listitem>
<para>In addition, the new <xref linkend="IMedium"
xreflabel="IMedium" /> interface is a generic interface for hard
disk, DVD and floppy images that contains the attributes and
methods shared between them. It can be considered a parent class
of the more specific interfaces for those images, which are now
IHardDisk2, IDVDImage2 and IFloppyImage2.</para>
<para>In each case, the "2" versions of these interfaces replace
the earlier versions that did not have the "2" suffix.
Previously, the IDVDImage and IFloppyImage interfaces were
entirely unrelated to IHardDisk.</para>
</listitem>
<listitem>
<para>As a result, all parts of the API that previously
referenced IHardDisk, IDVDImage or IFloppyImage or any of the
old subclasses are gone and will have replacements that use
IHardDisk2, IDVDImage2 and IFloppyImage2; see, for example,
IMachine::attachHardDisk2.</para>
</listitem>
<listitem>
<para>In particular, the IVirtualBox::hardDisks2 array replaces
the earlier IVirtualBox::hardDisks collection.</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para><xref linkend="IGuestOSType" xreflabel="IGuestOSType" /> was
extended to group operating systems into families and for 64-bit
support.</para>
</listitem>
<listitem>
<para>The <xref linkend="IHostNetworkInterface"
xreflabel="IHostNetworkInterface" /> interface was completely
rewritten to account for the changes in how Host Interface
Networking is now implemented in VirtualBox 2.1.</para>
</listitem>
<listitem>
<para>The IVirtualBox::machines2[] array replaces the former
IVirtualBox::machines collection.</para>
</listitem>
<listitem>
<para>Added <xref linkend="IHost__getProcessorFeature"
xreflabel="IHost::getProcessorFeature()" /> and <xref
linkend="ProcessorFeature" xreflabel="ProcessorFeature" />
enumeration.</para>
</listitem>
<listitem>
<para>The parameter list for <xref
linkend="IVirtualBox__createMachine"
xreflabel="IVirtualBox::createMachine()" /> was modified.</para>
</listitem>
<listitem>
<para>Added IMachine::pushGuestProperty.</para>
</listitem>
<listitem>
<para>New attributes in IMachine: <xref
linkend="IMachine__accelerate3DEnabled"
xreflabel="accelerate3DEnabled" />, HWVirtExVPIDEnabled, <xref
linkend="IMachine__guestPropertyNotificationPatterns"
xreflabel="guestPropertyNotificationPatterns" />, <xref
linkend="IMachine__CPUCount" xreflabel="CPUCount" />.</para>
</listitem>
<listitem>
<para>Added <xref linkend="IConsole__powerUpPaused"
xreflabel="IConsole::powerUpPaused()" /> and <xref
linkend="IConsole__getGuestEnteredACPIMode"
xreflabel="IConsole::getGuestEnteredACPIMode()" />.</para>
</listitem>
<listitem>
<para>Removed ResourceUsage enumeration.</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>
</book>
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