* add vboxDriver object to serve as a singleton global object that
  holds references to IVirtualBox and ISession to be shared among
  multiple connections. The vbox_driver is instantiated only once in
  the first call vboxGetDriverConnection function that is guarded by
  a mutex.

* call vbox API initialize only when the first connection is
  established, and likewise uninitialize when last connection
  disconnects. The prevents each subsequent connection from overwriting
  IVirtualBox/ISession instances of any other active connection that
  led to libvirtd segfaults. The virConnectOpen and virConnectClose
  implementations are guarded by mutex on the global vbox_driver_lock
  where the global vbox_driver object counts connectios and decides
  when it's safe to call vbox's init/uninit routines.

* add IVirutalBoxClient to vboxDriver and use it to in tandem with newer
  pfnClientInitialize/pfnClientUninitalize APIs for vbox versions that
  support it, to avoid usage of the old pfnComInitialize/Uninitialize.

If the stars are in the right position and you're building with
VBox >= 4.2.0 it will happen that compiler thinks an array
allocated on the stack may be unbounded:

In file included from vbox/vbox_V4_2.c:13:0:
vbox/vbox_tmpl.c: In function '_virtualboxCreateMachine':
vbox/vbox_tmpl.c:2811:1: error: stack usage might be unbounded [-Werror=stack-usage=]
 _virtualboxCreateMachine(vboxGlobalData *data, virDomainDefPtr def, IMachine **machine, char *uuidstr ATTRIBUTE_UNUSED)
 ^

Well, given how the variable is declared, I had some hard time
seeing it is actually bounded. Surprisingly compiler does not
complain because of -Wframe-larger-than. This is because
variable length arrays do not count into that warning.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

While trying to build with -Os couple of compile errors showed
up.

conf/domain_conf.c: In function 'virDomainChrRemove':
conf/domain_conf.c:13666:24: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     virDomainChrDefPtr ret, **arrPtr = NULL;
                        ^
Compiler fails to see that @ret is used only if set in the loop,
but whatever, there's no harm in initializing the variable.

In vboxAttachDrivesNew and _vboxAttachDrivesOld compiler thinks
that @rc may be used uninitialized. Well, not directly, but maybe
after some optimization. Yet again, no harm in initializing a
variable.

In file included from ./util/virthread.h:26:0,
                 from ./datatypes.h:28,
                 from vbox/vbox_tmpl.c:43,
                 from vbox/vbox_V3_1.c:37:
vbox/vbox_tmpl.c: In function '_vboxAttachDrivesOld':
./util/virerror.h:181:5: error: 'rc' may be used uninitialized in this function [-Werror=maybe-uninitialized]
     virReportErrorHelper(VIR_FROM_THIS, code, __FILE__,              \
     ^
In file included from vbox/vbox_V3_1.c:37:0:
vbox/vbox_tmpl.c:1041:14: note: 'rc' was declared here
     nsresult rc;
              ^
Yet again, one uninitialized variable:

qemu/qemu_driver.c: In function 'qemuDomainBlockCommit':
qemu/qemu_driver.c:17194:9: error: 'baseSource' may be used uninitialized in this function [-Werror=maybe-uninitialized]
         qemuDomainPrepareDiskChainElement(driver, vm, baseSource,
         ^

And another one:

storage/storage_backend_logical.c: In function 'virStorageBackendLogicalMatchPoolSource.isra.2':
storage/storage_backend_logical.c:618:33: error: 'thisSource' may be used uninitialized in this function [-Werror=maybe-uninitialized]
                       thisSource->devices[j].path))
                                 ^
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Also fix the curly brace to pass sytnax-check.

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

The IKeyboard COM object is needed to implement virDomainSendKey and is
available in all supported VBOX versions.

This function returned non-inactive domains instead of active
domains.  This broke virConnectNumOfDefinedDomains() and
virConnectListDefinedDomains() functions.

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

C guarantees that static variables are zero-initialized.  Some older
compilers (and also gcc -fno-zero-initialized-in-bss) create larger
binaries if you explicitly zero-initialize a static variable.

* src/libxl/libxl_driver.c: Fix initialization.
* src/lxc/lxc_controller.c: Likewise.
* src/openvz/openvz_util.c (openvzKBPerPages): Likewise.
* src/phyp/phyp_driver.c: Likewise.
* src/remote/remote_driver.c: Likewise.
* src/test/test_driver.c: Likewise.
* src/uml/uml_driver.c: Likewise.
* src/vbox/vbox_XPCOMCGlue.c: Likewise.
* src/vbox/vbox_tmpl.c: Likewise.
* src/xen/xen_driver.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

After rewriting the whole driver, Only version specified code is
remained in vbox_tmpl.c. So, this patch removes those unused macros
header files in vbox_tmpl.c.

This patch provides the new stroage driver for vbox. The work
is similar with patch 87dea4fc and the next b4022de3.

The API on IHardDiskAttachment is merged into IMediumAttachment.
So, we don't need it anymore.

The GetMedium will always return a IHardDisk object them.
In 2.2 and 3.0, it is what GetHardDisk exactly do. In 3.1 and later,
The IMedium is same as IHardDisk.

If the <path> in target element is not given, libvirt will put the
new volume in ~/.VirtualBox by default.

The CreateHardDiskMedium only support create HardDisk for medium
type, and it only works when vbox version >= 3.1. This patch make
the function workable with all vbox versions and rename it as
CreateHardDisk.

In vbox 2.2 and 3.0 this function will create a IHardDisk object.
In vbox later than 3.0, this function will create a IMedium object.

In old version, function FindMedium in UIVirtualBox doesn't work
for vbox2.2 and 3.0. We assume it will not be used when vbox in
these versions.

But when rewriting vboxStorageVolLookupByPath, we found it was
compatibe to use FindMedium to get a IHardDisk object, even in
vbox old versions. To achieve this, first make FindMedium call
FindHardDisk when VBOX_API_VERSION < 4000000.
Then change the argument type **IMedium to **IHardDisk. (As the
rules in heriachy, we can't transfer a IHardDisk to match
IMedium in output)

In vbox 2.2 and 3.0, the caller must be aware that they will get
a IHardDisk object in return.

We use typedef IMedium IHardDisk to make IHardDisk hierachy from
IMedium (Actually it did on vbox 2.2 and 3.0's C++ API).
So when calling
    VBOX_MEDIUM_FUNC_ARG*(IHardDisk, func, args)
we can directly replace it to
    gVBoxAPI.UIMedium.func(IHardDisk, args)

When dealing with this two types, we get some rules from it's
hierachy relationship.

When using IHardDisk and IMedium as input, we can't transfer a
IMedium to IHardDisk. Like:
    gVBoxAPI.UIHardDisk.func(IHardDisk *hardDisk, args)
    Here, we can't put a *IMedium as a argument.

When using IHardDisk and IMedium as output, we can't transfer a
IHardDisk to IMedium. Like:
    gVBoxAPI.UIMachine.GetMedium(IMedium **out)
    Here, we can't put a **IHardDisk as a argument. If this case
    do happen, we either change the API to GetHardDisk or write a
    new one.

This patch rewrites the following functions
    *vboxStorageOpen
    *vboxStorageClose
    *vboxConnectNumOfStoragePools
    *vboxConnectListStoragePools
    *vboxStoragePoolLookupByName

These functions do not call any vbox API, so I directly move it
from vbox_tmpl.c to vbox_storage.c

A small improvement is made on vboxConnectListStoragePools.
The if condition nnames == 1 is modified to nnames > 0. So if the
caller put more than one slot to get active storage pools, the new
function will return exactly one, while the old one would only
return 0.

We should follow the rules that CHECK macro only do checking works.
But this VBOX_OBJECT_CHECK and VBOX_OBJECT_HOST_CHECK declared some
varibles at the same time, which broke the rule. So the patch
removed this macros and dispatched it in source code.

The storage driver is still not rewriten at this point. So, I
remains the VBOX_OBJECT_CHECK macro in vbox_tmpl.c. But this will
finally be removed in patch 'vbox: Remove unused things in vbox_tmpl.c'

To prepare for introducing a single global driver, rename the
virDriver struct to virHypervisorDriver and the registration
API to virRegisterHypervisorDriver()

This patch seperate the domain driver and the network driver.

libvirt_driver_vbox_impl.la has been linked in the network driver.
So that the version specified codes in vbox_V*.c would only be
compiled once.

The vboxGetNetworkDriver provides a simple interface to get vbox
network driver.

This patch rewrites two public APIs. They are vboxNetworkUndefine
and vboxNetworkDestroy. They use the same core function
vboxNetworkUndefineDestroy. I merged it in one patch.

This patch actually contains two public API, virNetworkDefineXML
and virNetworkCreateXML. They use the same core function
vboxNetworkDefineCreateXML. So I merged it together.