https://bugzilla.redhat.com/show_bug.cgi?id=1058839

Commit f9f56340 for CVE-2014-0028 almost had the right idea - we
need to check the ACL rules to filter which events to send.  But
it overlooked one thing: the event dispatch queue is running in
the main loop thread, and therefore does not normally have a
current virIdentityPtr.  But filter checks can be based on current
identity, so when libvirtd.conf contains access_drivers=["polkit"],
we ended up rejecting access for EVERY event due to failure to
look up the current identity, even if it should have been allowed.

Furthermore, even for events that are triggered by API calls, it
is important to remember that the point of events is that they can
be copied across multiple connections, which may have separate
identities and permissions.  So even if events were dispatched
from a context where we have an identity, we must change to the
correct identity of the connection that will be receiving the
event, rather than basing a decision on the context that triggered
the event, when deciding whether to filter an event to a
particular connection.

If there were an easy way to get from virConnectPtr to the
appropriate virIdentityPtr, then object_event.c could adjust the
identity prior to checking whether to dispatch an event.  But
setting up that back-reference is a bit invasive.  Instead, it
is easier to delay the filtering check until lower down the
stack, at the point where we have direct access to the RPC
client object that owns an identity.  As such, this patch ends
up reverting a large portion of the framework of commit f9f56340.
We also have to teach 'make check' to special-case the fact that
the event registration filtering is done at the point of dispatch,
rather than the point of registration.  Note that even though we
don't actually use virConnectDomainEventRegisterCheckACL (because
the RegisterAny variant is sufficient), we still generate the
function for the purposes of documenting that the filtering
takes place.

Also note that I did not entirely delete the notion of a filter
from object_event.c; I still plan on using that for my upcoming
patch series for qemu monitor events in libvirt-qemu.so.  In
other words, while this patch changes ACL filtering to live in
remote.c and therefore we have no current client of the filtering
in object_event.c, the notion of filtering in object_event.c is
still useful down the road.

* src/check-aclrules.pl: Exempt event registration from having to
pass checkACL filter down call stack.
* daemon/remote.c (remoteRelayDomainEventCheckACL)
(remoteRelayNetworkEventCheckACL): New functions.
(remoteRelay*Event*): Use new functions.
* src/conf/domain_event.h (virDomainEventStateRegister)
(virDomainEventStateRegisterID): Drop unused parameter.
* src/conf/network_event.h (virNetworkEventStateRegisterID):
Likewise.
* src/conf/domain_event.c (virDomainEventFilter): Delete unused
function.
* src/conf/network_event.c (virNetworkEventFilter): Likewise.
* src/libxl/libxl_driver.c: Adjust caller.
* src/lxc/lxc_driver.c: Likewise.
* src/network/bridge_driver.c: Likewise.
* src/qemu/qemu_driver.c: Likewise.
* src/remote/remote_driver.c: Likewise.
* src/test/test_driver.c: Likewise.
* src/uml/uml_driver.c: Likewise.
* src/vbox/vbox_tmpl.c: Likewise.
* src/xen/xen_driver.c: Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 11f20e43)

Conflicts:
	daemon/remote.c - not backporting network events
	src/conf/network_event.c - likewise
	src/conf/network_event.h - likewise
	src/network/bridge_driver.c - likewise
	src/conf/domain_event.c - revert back to pre-CVE state
	src/conf/domain_event.h - likewise
	src/libxl/libxl_driver.c - likewise
	src/lxc/lxc_driver.c - likewise
	src/remote/remote_driver.c - likewise
	src/test/test_driver.c - likewise
	src/uml/uml_driver.c - likewise
	src/xen/xen_driver.c - likewise

Ever since ACL filtering was added in commit 76397360 (v1.1.1), a
user could still use event registration to obtain access to a
domain that they could not normally access via virDomainLookup*
or virConnectListAllDomains and friends.  We already have the
framework in the RPC generator for creating the filter, and
previous cleanup patches got us to the point that we can now
wire the filter through the entire object event stack.

Furthermore, whether or not domain:getattr is honored, use of
global events is a form of obtaining a list of networks, which
is covered by connect:search_domains added in a93cd08f (v1.1.0).
Ideally, we'd have a way to enforce connect:search_domains when
doing global registrations while omitting that check on a
per-domain registration.  But this patch just unconditionally
requires connect:search_domains, even when no list could be
obtained, based on the following observations:
1. Administrators are unlikely to grant domain:getattr for one
or all domains while still denying connect:search_domains - a
user that is able to manage domains will want to be able to
manage them efficiently, but efficient management includes being
able to list the domains they can access.  The idea of denying
connect:search_domains while still granting access to individual
domains is therefore not adding any real security, but just
serves as a layer of obscurity to annoy the end user.
2. In the current implementation, domain events are filtered
on the client; the server has no idea if a domain filter was
requested, and must therefore assume that all domain event
requests are global.  Even if we fix the RPC protocol to
allow for server-side filtering for newer client/server combos,
making the connect:serach_domains ACL check conditional on
whether the domain argument was NULL won't benefit older clients.
Therefore, we choose to document that connect:search_domains
is a pre-requisite to any domain event management.

Network events need the same treatment, with the obvious
change of using connect:search_networks and network:getattr.

* src/access/viraccessperm.h
(VIR_ACCESS_PERM_CONNECT_SEARCH_DOMAINS)
(VIR_ACCESS_PERM_CONNECT_SEARCH_NETWORKS): Document additional
effect of the permission.
* src/conf/domain_event.h (virDomainEventStateRegister)
(virDomainEventStateRegisterID): Add new parameter.
* src/conf/network_event.h (virNetworkEventStateRegisterID):
Likewise.
* src/conf/object_event_private.h (virObjectEventStateRegisterID):
Likewise.
* src/conf/object_event.c (_virObjectEventCallback): Track a filter.
(virObjectEventDispatchMatchCallback): Use filter.
(virObjectEventCallbackListAddID): Register filter.
* src/conf/domain_event.c (virDomainEventFilter): New function.
(virDomainEventStateRegister, virDomainEventStateRegisterID):
Adjust callers.
* src/conf/network_event.c (virNetworkEventFilter): New function.
(virNetworkEventStateRegisterID): Adjust caller.
* src/remote/remote_protocol.x
(REMOTE_PROC_CONNECT_DOMAIN_EVENT_REGISTER)
(REMOTE_PROC_CONNECT_DOMAIN_EVENT_REGISTER_ANY)
(REMOTE_PROC_CONNECT_NETWORK_EVENT_REGISTER_ANY): Generate a
filter, and require connect:search_domains instead of weaker
connect:read.
* src/test/test_driver.c (testConnectDomainEventRegister)
(testConnectDomainEventRegisterAny)
(testConnectNetworkEventRegisterAny): Update callers.
* src/remote/remote_driver.c (remoteConnectDomainEventRegister)
(remoteConnectDomainEventRegisterAny): Likewise.
* src/xen/xen_driver.c (xenUnifiedConnectDomainEventRegister)
(xenUnifiedConnectDomainEventRegisterAny): Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainGetXMLDesc): Likewise.
* src/libxl/libxl_driver.c (libxlConnectDomainEventRegister)
(libxlConnectDomainEventRegisterAny): Likewise.
* src/qemu/qemu_driver.c (qemuConnectDomainEventRegister)
(qemuConnectDomainEventRegisterAny): Likewise.
* src/uml/uml_driver.c (umlConnectDomainEventRegister)
(umlConnectDomainEventRegisterAny): Likewise.
* src/network/bridge_driver.c
(networkConnectNetworkEventRegisterAny): Likewise.
* src/lxc/lxc_driver.c (lxcConnectDomainEventRegister)
(lxcConnectDomainEventRegisterAny): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit f9f56340)

Conflicts:
	src/conf/object_event.c - not backporting event refactoring
	src/conf/object_event_private.h - likewise
	src/conf/network_event.c - not backporting network events
	src/conf/network_event.h - likewise
	src/network/bridge_driver.c - likewise
	src/access/viraccessperm.h - likewise
	src/remote/remote_protocol.x - likewise
	src/conf/domain_event.c - includes code that upstream has in object_event
	src/conf/domain_event.h - context
	src/libxl/libxl_driver.c - context
	src/lxc/lxc_driver.c - context
	src/remote/remote_driver.c - context, not backporting network events
	src/test/test_driver.c - context, not backporting network events
	src/uml/uml_driver.c - context
	src/xen/xen_driver.c - context

The function doesn't check whether the request is made for active or
inactive domain.  Thus when the domain is not running it still tries
accessing non-existing cgroups (priv->cgroup, which is NULL).

I re-made the function in order for it to work the same way it's qemu
counterpart does.

Reproducer:
 1) Define an LXC domain
 2) Do 'virsh memtune <domain> --hard-limit 133T'

Backtrace:
 Thread 6 (Thread 0x7fffec8c0700 (LWP 26826)):
 #0  0x00007ffff70edcc4 in virCgroupPathOfController (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", path=0x7fffec8bf718) at util/vircgroup.c:1764
 #1  0x00007ffff70e9206 in virCgroupSetValueStr (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", value=0x7fffe409f360 "1073741824")
     at util/vircgroup.c:669
 #2  0x00007ffff70e98b4 in virCgroupSetValueU64 (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", value=1073741824) at util/vircgroup.c:740
 #3  0x00007ffff70ee518 in virCgroupSetMemory (group=0x0, kb=1048576) at util/vircgroup.c:1904
 #4  0x00007ffff70ee675 in virCgroupSetMemoryHardLimit (group=0x0, kb=1048576)
     at util/vircgroup.c:1944
 #5  0x00005555557d54c8 in lxcDomainSetMemoryParameters (dom=0x7fffe40cc420,
     params=0x7fffe409f100, nparams=1, flags=0) at lxc/lxc_driver.c:774
 #6  0x00007ffff72c20f9 in virDomainSetMemoryParameters (domain=0x7fffe40cc420,
     params=0x7fffe409f100, nparams=1, flags=0) at libvirt.c:4051
 #7  0x000055555561365f in remoteDispatchDomainSetMemoryParameters (server=0x555555eb7e00,
     client=0x555555ec4b10, msg=0x555555eb94e0, rerr=0x7fffec8bfb70, args=0x7fffe40b8510)
     at remote_dispatch.h:7621
 #8  0x00005555556133fd in remoteDispatchDomainSetMemoryParametersHelper (server=0x555555eb7e00,
     client=0x555555ec4b10, msg=0x555555eb94e0, rerr=0x7fffec8bfb70, args=0x7fffe40b8510,
     ret=0x7fffe40b84f0) at remote_dispatch.h:7591
 #9  0x00007ffff73b293f in virNetServerProgramDispatchCall (prog=0x555555ec3ae0,
     server=0x555555eb7e00, client=0x555555ec4b10, msg=0x555555eb94e0)
     at rpc/virnetserverprogram.c:435
 #10 0x00007ffff73b207f in virNetServerProgramDispatch (prog=0x555555ec3ae0,
     server=0x555555eb7e00, client=0x555555ec4b10, msg=0x555555eb94e0)
     at rpc/virnetserverprogram.c:305
 #11 0x00007ffff73a4d2c in virNetServerProcessMsg (srv=0x555555eb7e00, client=0x555555ec4b10,
     prog=0x555555ec3ae0, msg=0x555555eb94e0) at rpc/virnetserver.c:165
 #12 0x00007ffff73a4e8d in virNetServerHandleJob (jobOpaque=0x555555ec3e30, opaque=0x555555eb7e00)
     at rpc/virnetserver.c:186
 #13 0x00007ffff7187f3f in virThreadPoolWorker (opaque=0x555555eb7ac0) at util/virthreadpool.c:144
 #14 0x00007ffff718733a in virThreadHelper (data=0x555555eb7890) at util/virthreadpthread.c:161
 #15 0x00007ffff468ed89 in start_thread (arg=0x7fffec8c0700) at pthread_create.c:308
 #16 0x00007ffff3da26bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>
(cherry picked from commit 9faf3f29)

The function doesn't check whether the request is made for active or
inactive domain.  Thus when the domain is not running it still tries
accessing non-existing cgroups (priv->cgroup, which is NULL).

I re-made the function in order for it to work the same way it's qemu
counterpart does.

Reproducer:
 1) Define an LXC domain
 2) Do 'virsh memtune <domain>'

Backtrace:
 Thread 6 (Thread 0x7fffec8c0700 (LWP 13387)):
 #0  0x00007ffff70edcc4 in virCgroupPathOfController (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", path=0x7fffec8bf750) at util/vircgroup.c:1764
 #1  0x00007ffff70e958c in virCgroupGetValueStr (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", value=0x7fffec8bf7c0) at util/vircgroup.c:705
 #2  0x00007ffff70e9d29 in virCgroupGetValueU64 (group=0x0, controller=3,
     key=0x7ffff75734bd "memory.limit_in_bytes", value=0x7fffec8bf810) at util/vircgroup.c:804
 #3  0x00007ffff70ee706 in virCgroupGetMemoryHardLimit (group=0x0, kb=0x7fffec8bf8a8)
     at util/vircgroup.c:1962
 #4  0x00005555557d590f in lxcDomainGetMemoryParameters (dom=0x7fffd40024a0,
     params=0x7fffd40027a0, nparams=0x7fffec8bfa24, flags=0) at lxc/lxc_driver.c:826
 #5  0x00007ffff72c28d3 in virDomainGetMemoryParameters (domain=0x7fffd40024a0,
     params=0x7fffd40027a0, nparams=0x7fffec8bfa24, flags=0) at libvirt.c:4137
 #6  0x000055555563714d in remoteDispatchDomainGetMemoryParameters (server=0x555555eb7e00,
     client=0x555555ebaef0, msg=0x555555ebb3e0, rerr=0x7fffec8bfb70, args=0x7fffd40024e0,
     ret=0x7fffd4002420) at remote.c:1895
 #7  0x00005555556052c4 in remoteDispatchDomainGetMemoryParametersHelper (server=0x555555eb7e00,
     client=0x555555ebaef0, msg=0x555555ebb3e0, rerr=0x7fffec8bfb70, args=0x7fffd40024e0,
     ret=0x7fffd4002420) at remote_dispatch.h:4050
 #8  0x00007ffff73b293f in virNetServerProgramDispatchCall (prog=0x555555ec3ae0,
     server=0x555555eb7e00, client=0x555555ebaef0, msg=0x555555ebb3e0)
     at rpc/virnetserverprogram.c:435
 #9  0x00007ffff73b207f in virNetServerProgramDispatch (prog=0x555555ec3ae0,
     server=0x555555eb7e00, client=0x555555ebaef0, msg=0x555555ebb3e0)
     at rpc/virnetserverprogram.c:305
 #10 0x00007ffff73a4d2c in virNetServerProcessMsg (srv=0x555555eb7e00, client=0x555555ebaef0,
     prog=0x555555ec3ae0, msg=0x555555ebb3e0) at rpc/virnetserver.c:165
 #11 0x00007ffff73a4e8d in virNetServerHandleJob (jobOpaque=0x555555ebc7e0, opaque=0x555555eb7e00)
     at rpc/virnetserver.c:186
 #12 0x00007ffff7187f3f in virThreadPoolWorker (opaque=0x555555eb7ac0) at util/virthreadpool.c:144
 #13 0x00007ffff718733a in virThreadHelper (data=0x555555eb7890) at util/virthreadpthread.c:161
 #14 0x00007ffff468ed89 in start_thread (arg=0x7fffec8c0700) at pthread_create.c:308
 #15 0x00007ffff3da26bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>
(cherry picked from commit f8c1cb90)

Unconditional use of getenv is not secure in setuid env.
While not all libvirt code runs in a setuid env (since
much of it only exists inside libvirtd) this is not always
clear to developers. So make all the code paranoid, even
if it only ever runs inside libvirtd.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 1e4a02bd)

Signed-off-by: NEric Blake <eblake@redhat.com>

Adjust these drivers to handle their Autostart functionality after each
of the drivers has gone through their Initialization functions

Convert the remaining methods in vircgroup.c to report errors
instead of returning errno values.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Similarly to qemu driver, we can use a helper function to
lookup a domain instead of copying multiple lines around.

With the majority of fields in the virLXCDriverPtr struct
now immutable or self-locking, there is no need for practically
any methods to be using the LXC driver lock. Only a handful
of helper APIs now need it.

The activeUsbHostdevs item in LXCDriver are lockable, but the lock has
to be called explicitly. Call the virObject(Un)Lock() in order to
achieve mutual exclusion once lxcDriverLock is removed.

The 'driver->caps' pointer can be changed on the fly. Accessing
it currently requires the global driver lock. Isolate this
access in a single helper, so a future patch can relax the
locking constraints.

Currently the virLXCDriverPtr struct contains an wide variety
of data with varying access needs. Move all the static config
data into a dedicated virLXCDriverConfigPtr object. The only
locking requirement is to hold the driver lock, while obtaining
an instance of virLXCDriverConfigPtr. Once a reference is held
on the config object, it can be used completely lockless since
it is immutable.

NB, not all APIs correctly hold the driver lock while getting
a reference to the config object in this patch. This is safe
for now since the config is never updated on the fly. Later
patches will address this fully.

Wire up the new virDomainCreate{XML}WithFiles methods in the
LXC driver, so that FDs get passed down to the init process.

The lxc_container code needs to do a little dance in order
to renumber the file descriptors it receives into linear
order, starting from STDERR_FILENO + 1.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The owner of this host devices should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

The owner of this disk device should be the root user of container.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Create parent directroy for hostdev automatically when we
start a lxc domain or attach a hostdev to a lxc domain.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

Ensure that all APIs which list domain objects filter
them against the access control system.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Insert calls to the ACL checking APIs in all LXC driver
entrypoints.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

As a consequence of the cgroup layout changes from commit 'cfed9ad4', the
lxcDomainGetSchedulerParameters[Flags]()' and lxcGetSchedulerType() APIs
failed to return data for a non running domain.  This can be seen through
a 'virsh schedinfo <domain>' command which returns:

Scheduler      : Unknown
error: Requested operation is not valid: cgroup CPU controller is not mounted

Prior to that change a non running domain would return:

Scheduler      : posix
cpu_shares     : 0
vcpu_period    : 0
vcpu_quota     : 0
emulator_period: 0
emulator_quota : 0

This patch will restore the capability to return configuration only data
for a non running domain regardless of whether cgroups are available.

The LXC, QEMU, and LibXL drivers have all merged their handling of
the attach/update/modify device APIs into one large

  'xxxxDomainModifyDeviceFlags'

which then does a 'switch()' based on the actual API being invoked.
While this saves some lines of code, it is not really all that
significant in the context of the driver API impls as a whole.

This merger of the handling of different APIs creates pain when
wanting to automated analysis of the code and do things which
are specific to individual APIs. The slight duplication of code
from unmerged the API impls, is preferrable to allow for easier
automated analysis.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The individual hypervisor drivers were directly referencing
APIs in virnodesuspend.c in their virDriverPtr struct. Separate
these methods, so there is always a wrapper in the hypervisor
driver. This allows the unused virConnectPtr args to be removed
from the virnodesuspend.c file. Again this will ensure that
ACL checks will only be performed on invocations that are
directly associated with public API usage.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The individual hypervisor drivers were directly referencing
APIs in src/nodeinfo.c in their virDriverPtr struct. Separate
these methods, so there is always a wrapper in the hypervisor
driver. This allows the unused virConnectPtr args to be
removed from the nodeinfo.c file. Again this will ensure that
ACL checks will only be performed on invocations that are
directly associated with public API usage.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Currently the virGetHostname() API has a bogus virConnectPtr
parameter. This is because virtualization drivers directly
reference this API in their virDriverPtr tables, tieing its
API design to the public virConnectGetHostname API design.

This also causes problems for access control checks since
these must only be done for invocations from the public
API, not internal invocation.

Remove the bogus virConnectPtr parameter, and make each
hypervisor driver provide a dedicated function for the
driver API impl. This will allow access control checks
to be easily inserted later.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.

Ensure that all drivers implementing public APIs use a
naming convention for their implementation that matches
the public API name.

eg for the public API   virDomainCreate make sure QEMU
uses qemuDomainCreate and not qemuDomainStart
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Ensure that the driver struct field names match the public
API names. For an API virXXXX we must have a driver struct
field xXXXX. ie strip the leading 'vir' and lowercase any
leading uppercase letters.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of calling virCgroupForDomain every time we need
the virCgrouPtr instance, just do it once at Vm startup
and cache a reference to the object in virLXCDomainObjPrivatePtr
until shutdown of the VM. Removing the virCgroupPtr from
the LXC driver state also means we don't have stale mount
info, if someone mounts the cgroups filesystem after libvirtd
has been started
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The virCgroupMounted method is badly named, since a controller can be
mounted, but disabled in the current object. Rename the method to be
virCgroupHasController. Also make it tolerant to a  NULL virCgroupPtr
and out-of-range controller index, to avoid duplication of these
checks in all callers
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Currently when getting an instance of virCgroupPtr we will
create the path in all cgroup controllers. Only at the virt
driver layer are we attempting to filter controllers. This
is bad because the mere act of creating the dirs in the
controllers can have a functional impact on the kernel,
particularly for performance.

Update the virCgroupForDriver() method to accept a bitmask
of controllers to use. Only create dirs in the controllers
that are requested. When creating cgroups for domains,
respect the active controller list from the parent cgroup
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Move the xmlopt and caps arguments to the end of the argument list.

This patch adds instrumentation that will allow hypervisor drivers to
fill and validate domain and device definitions after parsed by the XML
parser.

With this patch, after the XML is parsed, a callback to the driver is
issued requesting to fill and validate driver specific details of the
configuration. This allows to use sensible defaults and checks on a per
driver basis at the time the XML is parsed.

Two callback pointers are stored in the new virDomainXMLConf object:
* virDomainDeviceDefPostParseCallback (devicesPostParseCallback)
  - called for a single device parsed and for every single device in a
    domain config. A virDomainDeviceDefPtr is passed along with the
    domain definition and virCaps.

* virDomainDefPostParseCallback, (domainPostParseCallback)
  - A callback that is meant to process the domain config after it's
  parsed.  A virDomainDefPtr is passed along with virCaps.

Both types of callbacks support arbitrary opaque data passed for the
callback functions.

Errors may be reported in those callbacks resulting in a XML parsing
failure.

This patch is the result of running:

for i in $(git ls-files | grep -v html | grep -v \.po$ ); do
  sed -i -e "s/virDomainXMLConf/virDomainXMLOption/g" -e "s/xmlconf/xmlopt/g" $i
done

and a few manual tweaks.

The sysinfo code used by QEMU is trivially portable to the
LXC driver