The libvirt coding standard is to use 'function(...args...)'
instead of 'function (...args...)'. A non-trivial number of
places did not follow this rule and are fixed in this patch.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

In Xen 4.2, xs.h is deprecated in favor of xenstore.h.  xs.h now
contains

#warning xs.h is deprecated use xenstore.h instead
#include <xenstore.h>

which fails compilation when warnings are treated as errors.

Introduce a configure-time check for xenstore.h and if found,
use it instead of xs.h.

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

When the XenStore tdb lives persistently and is not cleared between host
reboots, Xend (version 3.4 and 4.1) re-creates the domain information
located in XenStore below /vm/$UUID. (According to the xen-3.2-commit
hg265950e3df69 to fix a problem when locally migrating a domain to the
host itself.)

When doing so a version number is added to the UUID separated by one
dash, which confuses xenStoreDomainIntroduced(): It iterates over all
domains and tries to lookup all inactive domains using
xenStoreDomainGetUUID(), which fails if the running domain is renamed:
virUUIDParse() fails to parse the versioned UUID and the domain is
flagged as missing. When this happens the function delays .2s and
re-tries 20 times again, multiplied by the number of renamed VMs.
  14:48:38.878: 4285: debug : xenStoreDomainIntroduced:1354 : Some domains were missing, trying again

This adds a significant delay:
  # time virsh list >/dev/null
  real    0m6.529s
  # xenstore-list /vm
  00000000-0000-0000-0000-000000000000
  00000000-0000-0000-0000-000000000000-1
  00000000-0000-0000-0000-000000000000-2
  00000000-0000-0000-0000-000000000000-3
  00000000-0000-0000-0000-000000000000-4
  00000000-0000-0000-0000-000000000000-5
  7c06121e-90c3-93d4-0126-50481d485cca
  00000000-0000-0000-0000-000000000000-6
  00000000-0000-0000-0000-000000000000-7
  144ad19d-dfb4-2f80-8045-09196bb8784f
  00000000-0000-0000-0000-000000000000-8
  144ad19d-dfb4-2f80-8045-09196bb8784f-1
  00000000-0000-0000-0000-000000000000-9
  00000000-0000-0000-0000-000000000000-10
  00000000-0000-0000-0000-000000000000-11
  00000000-0000-0000-0000-000000000000-12
  00000000-0000-0000-0000-000000000000-13
  00000000-0000-0000-0000-000000000000-14
  144ad19d-dfb4-2f80-8045-09196bb8784f-2
  00000000-0000-0000-0000-000000000000-15
  144ad19d-dfb4-2f80-8045-09196bb8784f-3
  00000000-0000-0000-0000-000000000000-16

The patch adds truncation of the UUID as read from the XenStore path
before passing it to virUUIDParse().

The same issue is reported at
<http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=666135>
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

This is a follow up patch of commit f9ce7dad, it modifies all
the files which declare the copyright like "See COPYING.LIB for
the License of this software" to use the detailed/consistent one.

And deserts the outdated comments like:

 * libvirt-qemu.h:
 * Summary: qemu specific interfaces
 * Description: Provides the interfaces of the libvirt library to handle
 *              qemu specific methods
 *
 * Copy:  Copyright (C) 2010, 2012 Red Hat, Inc.

Uses the more compact style like:

 * libvirt-qemu.h: Interfaces specific for QEMU/KVM driver
 *
 * Copyright (C) 2010, 2012 Red Hat, Inc.

Update the legacy Xen drivers to use virReportError instead of
the statsError, virXenInotifyError, virXenStoreError,
virXendError, xenUnifiedError, xenXMError custom macros
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Return statements with parameter enclosed in parentheses were modified
and parentheses were removed. The whole change was scripted, here is how:

List of files was obtained using this command:
git grep -l -e '\<return\s*([^()]*\(([^()]*)[^()]*\)*)\s*;' |             \
grep -e '\.[ch]$' -e '\.py$'

Found files were modified with this command:
sed -i -e                                                                 \
's_^\(.*\<return\)\s*(\(\([^()]*([^()]*)[^()]*\)*\))\s*\(;.*$\)_\1 \2\4_' \
-e 's_^\(.*\<return\)\s*(\([^()]*\))\s*\(;.*$\)_\1 \2\3_'

Then checked for nonsense.

The whole command looks like this:
git grep -l -e '\<return\s*([^()]*\(([^()]*)[^()]*\)*)\s*;' |             \
grep -e '\.[ch]$' -e '\.py$' | xargs sed -i -e                            \
's_^\(.*\<return\)\s*(\(\([^()]*([^()]*)[^()]*\)*\))\s*\(;.*$\)_\1 \2\4_' \
-e 's_^\(.*\<return\)\s*(\([^()]*\))\s*\(;.*$\)_\1 \2\3_'

On 64-bit platforms, unsigned long and unsigned long long are
identical, so we don't have to worry about overflow checks.
On 32-bit platforms, anywhere we narrow unsigned long long back
to unsigned long, we have to worry about overflow; it's easier
to do this in one place by having most of the code use the same
or wider types, and only doing the narrowing at the last minute.
Therefore, the memory set commands remain unsigned long, and
the memory get command now centralizes the overflow check into
libvirt.c, so that drivers don't have to repeat the work.

This also fixes a bug where xen returned the wrong value on
failure (most APIs return -1 on failure, but getMaxMemory
must return 0 on failure).

* src/driver.h (virDrvDomainGetMaxMemory): Use long long.
* src/libvirt.c (virDomainGetMaxMemory): Raise overflow.
* src/test/test_driver.c (testGetMaxMemory): Fix driver.
* src/rpc/gendispatch.pl (name_to_ProcName): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorGetMaxMemory): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainGetMaxMemory): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainGetMaxMemory):
Likewise.
* src/xen/xend_internal.h (xenDaemonDomainGetMaxMemory):
Likewise.
* src/xen/xm_internal.c (xenXMDomainGetMaxMemory): Likewise.
* src/xen/xm_internal.h (xenXMDomainGetMaxMemory): Likewise.
* src/xen/xs_internal.c (xenStoreDomainGetMaxMemory): Likewise.
* src/xen/xs_internal.h (xenStoreDomainGetMaxMemory): Likewise.
* src/xenapi/xenapi_driver.c (xenapiDomainGetMaxMemory):
Likewise.
* src/esx/esx_driver.c (esxDomainGetMaxMemory): Likewise.
* src/libxl/libxl_driver.c (libxlDomainGetMaxMemory): Likewise.
* src/qemu/qemu_driver.c (qemudDomainGetMaxMemory): Likewise.
* src/lxc/lxc_driver.c (lxcDomainGetMaxMemory): Likewise.
* src/uml/uml_driver.c (umlDomainGetMaxMemory): Likewise.

The console path in xenstore is /local/domain/<id>/console/tty
for PV guests (PV console) and /local/domain/<id>/serial/0/tty
(serial console) for HVM guests.  Similar to Xen's in-tree console
client, read the correct path for PV vs HVM.

https://bugzilla.redhat.com/show_bug.cgi?id=648855 mentioned a
misuse of 'an' where 'a' is proper; that has since been fixed,
but a search found other problems (some were a spelling error for
'and', while most were fixed by 'a').

* daemon/stream.c: Fix grammar.
* src/conf/domain_conf.c: Likewise.
* src/conf/domain_event.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/esx/esx_vi.c: Likewise.
* src/rpc/virnetclient.c: Likewise.
* src/rpc/virnetserverprogram.c: Likewise.
* src/storage/storage_backend_fs.c: Likewise.
* src/util/conf.c: Likewise.
* src/util/dnsmasq.c: Likewise.
* src/util/iptables.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xend_internal.c: Likewise.
* src/xen/xs_internal.c: Likewise.
* tools/virsh.c: Likewise.

Found by:

for f in $(sed -n 's/.*Drv[^ ]* \([^;]*\);.*/\1/p' src/xen/xen_driver.h)
do
  git grep "\(\.\|->\)$f\b" src/xen
done | cat

and looking through the resulting list to see which callback struct
members are still necessary.

* src/xen/xen_driver.h (xenUnifiedDriver): Drop all callbacks that
are only used directly.
* src/xen/xen_hypervisor.c (xenHypervisorDriver): Shrink list.
* src/xen/xen_inotify.c (xenInotifyDriver): Likewise.
* src/xen/xend_internal.c (xenDaemonDriver): Likewise.
* src/xen/xm_internal.c (xenXMDriver): Likewise.
* src/xen/xs_internal.c (xenStoreDriver): Likewise.

Using C99 initializers and xen-specific prefixes will make it
so that future patches are less likely to add callback members
to the xenUnifiedDriver struct, since the goal is to get rid
of the callback struct in the first place.

* src/xen/xen_driver.h (xenUnifiedDriver): Rename all struct
members, to make it obvious which ones are still in use.
* src/xen/xen_driver.c: Update all callers.
* src/xen/xen_hypervisor.c (xenHypervisorDriver): Rewrite with C99
initializers.
* src/xen/xend_internal.c (xenDaemonDriver): Likewise.
* src/xen/xs_internal.c (xenStoreDriver): Likewise.
* src/xen/xm_internal.c (xenXMDriver): Likewise.
* src/xen/xen_inotify.c (xenInotifyDriver): Likewise.

Build failure on xenapi_driver from compiler warnings (flags was unused).

Build failure on xen (incorrect number of arguments).  And in fixing
that, I obeyed the comments of struct xenUnifiedDriver that state
that we want to minimize the number of callback functions in that
struct, not add to it.

* src/xen/xen_driver.c (xenUnifiedDomainDestroyFlags): Use correct
arguments.
(xenUnifiedDomainDestroy): Simplify.
* src/xen/xen_driver.h (xenUnifiedDriver): Remove unused callback.
* src/xen/xen_hypervisor.c (xenHypervisorDestroyDomain): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainDestroy): Likewise.
* src/xen/xend_internal.h (xenDaemonDomainDestroyFlags): Likewise.
* src/xen/xm_internal.c (xenXMDriver): Likewise.
* src/xen/xs_internal.c (xenStoreDriver): Likewise.
* src/xen/xen_inotify.c (xenInotifyDriver): Likewise.
* src/xenapi/xenapi_driver.c (xenapiDomainDestroyFlags): Reject
unknown flags.

Also fix a logic bug in xenXMDomain{Attach,Detach}DeviceFlags,
where (flags & VIR_DOMAIN_DEVICE_MODIFY_CURRENT) is always false.

* src/xen/xen_driver.c (xenUnifiedDomainXMLFromNative)
(xenUnifiedDomainXMLToNative, xenUnifiedDomainBlockPeek): Reject
unknown flags.
* src/xen/xen_hypervisor.c (xenHypervisorOpen)
(xenHypervisorGetDomainState): Likewise.
* src/xen/xen_inotify.c (xenInotifyOpen): Likewise.
* src/xen/xs_internal.c (xenStoreOpen, xenStoreDomainGetState)
(xenStoreDomainReboot): Likewise.
* src/xen/xend_internal.c (xenDaemonOpen, xenDaemonDomainReboot)
(xenDaemonDomainCoreDump, xenDaemonDomainGetState)
(xenDaemonDomainMigratePrepare, xenDaemonDomainSetVcpusFlags,
xenDaemonDomainGetVcpusFlags, xenDaemonAttachDeviceFlags,
xenDaemonDetachDeviceFlags): Likewise.
(xenDaemonDomainGetXMLDesc): Prefer unsigned flags.
* src/xen/xend_internal.h (xenDaemonDomainGetXMLDesc): Likewise.
* src/xen/xm_internal.h (xenXMDomainGetXMLDesc): Likewise.
* src/xen/xm_internal.c (xenXMDomainGetXMLDesc): Likewise.
(xenXMOpen, xenXMDomainGetState, xenXMDomainSetVcpusFlags)
(xenXMDomainGetVcpusFlags): Reject unknown flags.
(xenXMDomainAttachDeviceFlags, xenXMDomainDetachDeviceFlags):
Likewise, and avoid always-false conditional.
* src/xen/xen_driver.h (XEN_MIGRATION_FLAGS): New define.

Now that the public APIs always use unsigned flags, the internal
driver callbacks might as well do likewise.

* src/driver.h (vrDrvOpen, virDrvDomainCoreDump)
(virDrvDomainGetXMLDesc, virDrvNetworkGetXMLDesc)
(virDrvNWFilterGetXMLDesc): Update type.
* src/remote/remote_protocol.x (remote_open_args)
(remote_domain_core_dump_args, remote_domain_get_xml_desc_args)
(remote_network_get_xml_desc_args)
(remote_nwfilter_get_xml_desc_args): Likewise.
* src/test/test_driver.c: Update clients.
* src/remote/remote_driver.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xen_hypervisor.h: Likewise.
* src/xen/xen_driver.c: Likewise.
* src/xen/xend_internal.c: Likewise.
* src/xen/xend_internal.h: Likewise.
* src/xen/xm_internal.c: Likewise.
* src/xen/xm_internal.h: Likewise.
* src/xen/xs_internal.c: Likewise.
* src/xen/xs_internal.h: Likewise.
* src/xen/xen_inotify.c: Likewise.
* src/xen/xen_inotify.h: Likewise.
* src/phyp/phyp_driver.c: Likewise.
* src/openvz/openvz_driver.c: Likewise.
* src/vmware/vmware_driver.c: Likewise.
* src/vbox/vbox_driver.c: Likewise.
* src/vbox/vbox_tmpl.c: Likewise.
* src/xenapi/xenapi_driver.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/esx/esx_interface_driver.c: Likewise.
* src/esx/esx_network_driver.c: Likewise.
* src/esx/esx_storage_driver.c: Likewise.
* src/esx/esx_device_monitor.c: Likewise.
* src/esx/esx_secret_driver.c: Likewise.
* src/esx/esx_nwfilter_driver.c: Likewise.
* src/interface/netcf_driver.c: Likewise.
* src/nwfilter/nwfilter_driver.c: Likewise.
* src/libxl/libxl_driver.c: Likewise.
* src/qemu/qemu_driver.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
* src/uml/uml_driver.c: Likewise.
* src/network/bridge_driver.c: Likewise.
* src/secret/secret_driver.c: Likewise.
* src/storage/storage_driver.c: Likewise.
* src/node_device/node_device_hal.c: Likewise.
* src/node_device/node_device_udev.c: Likewise.
* src/remote_protocol-structs: Likewise.

Since we virEventRegisterDefaultImpl is now a public API, callers need
a way to invoke the default registered Handle and Timeout functions. We
already have general functions for these internally, so promote
them to the public API.

v2:
    Actually add APIs to libvirt.h

Reason is currently always set to 0 (i.e., *_UNKNOWN).

* src/driver.h: Stub code for new API
* src/esx/esx_driver.c, src/libxl/libxl_driver.c,
  src/lxc/lxc_driver.c, src/openvz/openvz_driver.c,
  src/phyp/phyp_driver.c, src/qemu/qemu_driver.c,
  rc/remote/remote_driver.c, rc/test/test_driver.c,
  src/uml/uml_driver.c, src/vbox/vbox_tmpl.c,
  src/vmware/vmware_driver.c, src/xen/xen_driver.c,
  src/xen/xen_driver.h, src/xen/xen_hypervisor.c,
  src/xen/xen_inotify.c, src/xen/xend_internal.c,
  src/xen/xm_internal.c, src/xen/xs_internal.c,
  src/xenapi/xenapi_driver.c: Add dummy entries in driver
  table for new APIs

These VIR_XXXX0 APIs make us confused, use the non-0-suffix APIs instead.

How do these coversions works? The magic is using the gcc extension of ##.
When __VA_ARGS__ is empty, "##" will swallow the "," in "fmt," to
avoid compile error.

example: origin				after CPP
	high_level_api("%d", a_int)	low_level_api("%d", a_int)
	high_level_api("a  string")	low_level_api("a  string")

About 400 conversions.

8 special conversions:
VIR_XXXX0("") -> VIR_XXXX("msg") (avoid empty format) 2 conversions
VIR_XXXX0(string_literal_with_%) -> VIR_XXXX(%->%%) 0 conversions
VIR_XXXX0(non_string_literal) -> VIR_XXXX("%s", non_string_literal)
  (for security) 6 conversions
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>

And from all related macros and functions.

Done mechanically with:
$ git grep -l '\bDEBUG0\? *(' | xargs -L1 sed -i 's/\bDEBUG0\? *(/VIR_&/'

followed by manual deletion of qemudDebug in daemon/libvirtd.c, along
with a single 'make syntax-check' fallout in the same file, and the
actual deletion in src/util/logging.h.

* src/util/logging.h (DEBUG, DEBUG0): Delete.
* daemon/libvirtd.h (qemudDebug): Likewise.
* global: Change remaining clients over to VIR_DEBUG counterpart.

Pure cosmetic change.

Suggested by danpb, as it's not up-to-date anymore and
lacks many functions that were added to libvirtd.

* src/xen/xen_driver.h (includes): Include main xen headers
here...
* src/xen/xs_internal.c (includes): ...rather than in just one of
the sub-drivers.

* src/xen/xen_driver.h (xenUnifiedDriver): Remove now-unused
domainGetMaxVcpus, domainSetVcpus.
* src/xen/proxy_internal.c (xenProxyDriver): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorDriver): Likewise.
* src/xen/xen_inotify.c (xenInotifyDriver): Likewise.
* src/xen/xend_internal.c (xenDaemonDriver)
(xenDaemonDomainSetVcpus): Likewise.
* src/xen/xm_internal.c (xenXMDriver, xenXMDomainSetVcpus):
Likewise.
* src/xen/xs_internal.c (xenStoreDriver): Likewise.

To allow the new virDomainUpdateDeviceFlags() API to be universally
used with all drivers, this patch adds an impl to all the current
drivers which support CDROM or Floppy disk media change via the
current virDomainAttachDeviceFlags API

* src/qemu/qemu_driver.c, src/vbox/vbox_tmpl.c,
  src/xen/proxy_internal.c, src/xen/xen_driver.c,
  src/xen/xend_internal.c: Implement media change via the
  virDomainUpdateDeviceFlags API
* src/xen/xen_driver.h, src/xen/xen_hypervisor.c,
  src/xen/xen_inotify.c, src/xen/xm_internal.c,
  src/xen/xs_internal.c: Stubs for Xen driver entry points

* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done

Prior to this patch, there was an inconsistent mix between GNU and C99.

For consistency, and potential portability to other compilers, stick
with the C99 vararg macro syntax.

* src/conf/cpu_conf.c (virCPUReportError): Use C99 rather than GNU
  vararg macro syntax.
* src/conf/domain_conf.c (virDomainReportError): Likewise.
* src/conf/domain_event.c (eventReportError): Likewise.
* src/conf/interface_conf.c (virInterfaceReportError): Likewise.
* src/conf/network_conf.c (virNetworkReportError): Likewise.
* src/conf/node_device_conf.h (virNodeDeviceReportError): Likewise.
* src/conf/secret_conf.h (virSecretReportError): Likewise.
* src/conf/storage_conf.h (virStorageReportError): Likewise.
* src/esx/esx_device_monitor.c (ESX_ERROR): Use C99 rather than
  GNU vararg macro syntax.
* src/esx/esx_driver.c (ESX_ERROR): Likewise.
* src/esx/esx_interface_driver.c (ESX_ERROR): Likewise.
* src/esx/esx_network_driver.c (ESX_ERROR): Likewise.
* src/esx/esx_secret_driver.c (ESX_ERROR): Likewise.
* src/esx/esx_storage_driver.c (ESX_ERROR): Likewise.
* src/esx/esx_util.c (ESX_ERROR): Likewise.
* src/esx/esx_vi.c (ESX_VI_ERROR): Likewise.
* src/esx/esx_vi_methods.c (ESX_VI_ERROR): Likewise.
* src/esx/esx_vi_types.c (ESX_VI_ERROR): Likewise.
* src/esx/esx_vmx.c (ESX_ERROR): Likewise.
* src/util/hostusb.c (usbReportError): Use C99 rather than GNU
  vararg macro syntax.
* src/util/json.c (virJSONError): Likewise.
* src/util/macvtap.c (ReportError): Likewise.
* src/util/pci.c (pciReportError): Likewise.
* src/util/stats_linux.c (virStatsError): Likewise.
* src/util/util.c (virUtilError): Likewise.
* src/util/xml.c (virXMLError): Likewise.
* src/xen/proxy_internal.c (virProxyError): Use C99 rather than
  GNU vararg macro syntax.
* src/xen/sexpr.c (virSexprError): Likewise.
* src/xen/xen_driver.c (xenUnifiedError): Likewise.
* src/xen/xen_hypervisor.c (virXenError): Likewise.
* src/xen/xen_inotify.c (virXenInotifyError): Likewise.
* src/xen/xend_internal.c (virXendError): Likewise.
* src/xen/xm_internal.c (xenXMError): Likewise.
* src/xen/xs_internal.c (virXenStoreError): Likewise.
* src/cpu/cpu.h (virCPUReportError): Use C99 rather than GNU
  vararg macro syntax.
* src/datatypes.c (virLibConnError): Likewise.
* src/interface/netcf_driver.c (interfaceReportError): Likewise.
* src/libvirt.c (virLibStreamError): Likewise.
* src/lxc/lxc_conf.h (lxcError): Likewise.
* src/network/bridge_driver.c (networkReportError): Likewise.
* src/nodeinfo.c (nodeReportError): Likewise.
* src/opennebula/one_conf.h (oneError): Likewise.
* src/openvz/openvz_conf.h (openvzError): Likewise.
* src/phyp/phyp_driver.c (PHYP_ERROR): Likewise.
* src/qemu/qemu_conf.h (qemuReportError): Likewise.
* src/remote/remote_driver.c (errorf): Likewise.
* src/security/security_driver.h (virSecurityReportError): Likewise.
* src/test/test_driver.c (testError): Likewise.
* src/uml/uml_conf.h (umlReportError): Likewise.
* src/vbox/vbox_driver.c (vboxError): Likewise.
* src/vbox/vbox_tmpl.c (vboxError): Likewise.

Implementation of domain{Attach,Detach}DeviceFlags handlers
in the drivers.

* src/xen/xs_internal.c (xenStoreDomainIntroduced): Don't use -1
as an allocation size upon xenStoreNumOfDomains failure.
(xenStoreDomainReleased): Likewise.

Signed-off-by: NChris Lalancette <clalance@redhat.com>

The Xen code for making HVM VT-d PCI passthrough attach and detach
wasn't working properly:

1)  In xenDaemonAttachDevice(), we were always trying to reconfigure
a PCI passthrough device, even the first time we added it.  This was
because the code in virDomainXMLDevID() was not checking xenstore for
the existence of the device, and always returning 0 (meaning that
the device already existed).

2)  In xenDaemonDetachDevice(), we were trying to use "device_destroy"
to detach a PCI device.  While you would think that is the right
method to call, it's actually wrong for PCI devices.  In particular,
in upstream Xen (and soon in RHEL-5 Xen), device_configure is actually
used to destroy a PCI device.

To fix the attach
problem I add a lookup into xenstore to see if the device we are
trying to attach already exists.  To fix the detach problem I change
it so that for PCI detach (only), we use device_configure with the
appropriate sxpr to do the detachment.

* src/xen/xend_internal.c: don't use device_destroy for PCI devices
  and fix the other issues.
* src/xen/xs_internal.c src/xen/xs_internal.h: add
  xenStoreDomainGetPCIID()

Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.

The xenstore database sometimes has stale domain IDs which are not
present in the hypervisor anymore. Filter these out to avoid causing
confusion

* src/xen/xs_internal.c: Filter domain IDs against HV's list
* src/xen/xen_hypervisor.h, src/xen/xen_hypervisor.c: Add new
  xenHypervisorHasDomain() method for checking ID validity