filename is not initialized to NULL while it's unconditionally freed in
the error path.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

On CentOS5:
If "virsh edit $DOM" is used and an error happens (for example changing
any live cycle action to a non-existing value), libvirt forgets that
$DOM exists, since it is already removed from the internal hash tables,
which are used for domain lookup.
In once case (unreproducible) even the persistent configuration
/etc/xen/$DOM was deleted.

Instead of using the compound function xenXMConfigSaveFile() explicitly
use xenFomatXM() and virConfWriteFile() to distinguish between a failure
in converting the libvirt definition to the xen-xm format and a problem
when writing the file.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

On CentOS5 with xen-3.0.3:

 Program received signal SIGSEGV, Segmentation fault.
 virFree (ptrptr=0x8) at util/memory.c:310
 310         free(*(void**)ptrptr);
 (gdb) bt
 #0  virFree (ptrptr=0x8) at util/memory.c:310
 #1  0x00002aaaaae167c8 in xenXMDomainDefineXML (conn=0x694e80, xml=0x6b2ce0 "P\fk") at xen/xm_internal.c:1199
 #2  0x00002aaaaae070d7 in xenUnifiedDomainDefineXML (conn=0x8,
     xml=0x6ac040 "<domain type='xen'>\n  <name>pv</name>\n  <uuid>20291bc0-453a-4d6c-c6ac-4e5af63b932c</uuid>\n  <memory>1048576</memory>\n  <currentMemory>1048576</currentMemory>\n  <vcpu>1</vcpu>\n  <os>\n    <type arch='x8"...) at xen/xen_driver.c:1524
 #3  0x00002aaaaada7803 in virDomainDefineXML (conn=0x694e80,
     xml=0x6ac040 "<domain type='xen'>\n  <name>pv</name>\n  <uuid>20291bc0-453a-4d6c-c6ac-4e5af63b932c</uuid>\n  <memory>1048576</memory>\n  <currentMemory>1048576</currentMemory>\n  <vcpu>1</vcpu>\n  <os>\n    <type arch='x8"...) at libvirt.c:7823
 #4  0x0000000000426173 in cmdEdit (ctl=0x7fffffffb8e0, cmd=<value optimized out>) at virsh.c:14882
 #5  0x000000000041c9ce in vshCommandRun (ctl=0x7fffffffb8e0, cmd=0x658c50) at virsh.c:17712
 #6  0x000000000042c3b9 in main (argc=1, argv=<value optimized out>) at virsh.c:19317
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

libvirt supports 4 different versions of the user-land XenD daemon. When
queried the daemon just returns its generation number, which is hard to
match to the version of the Xen tools.

Replace the magic generation numbers by named enum definitions to
improve code readability.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

Rename virFormatMacAddr, virGenerateMacAddr and virParseMacAddr
to virMacAddrFormat, virMacAddrGenerate and virMacAddrParse
respectively

In preparation for the patch to include Murmurhash3, which
introduces a virhashcode.h and virhashcode.c files, rename
the existing hash.h and hash.c to virhash.h and virhash.c
respectively.

Add a new API virDomainShutdownFlags and define:

    VIR_DOMAIN_SHUTDOWN_DEFAULT        = 0,
    VIR_DOMAIN_SHUTDOWN_ACPI_POWER_BTN = (1 << 0),
    VIR_DOMAIN_SHUTDOWN_GUEST_AGENT    = (1 << 1),

Also define some flags for the reboot API

    VIR_DOMAIN_REBOOT_DEFAULT        = 0,
    VIR_DOMAIN_REBOOT_ACPI_POWER_BTN = (1 << 0),
    VIR_DOMAIN_REBOOT_GUEST_AGENT    = (1 << 1),

Although these two APIs currently have the same flags, using
separate enums allows them to expand separately in the future.

Add stub impls of the new API for all existing drivers

by dereferencing a NULL pointer in the call to
virNodeSuspendGetTargetMask.

While we still don't want to enable gcc's new -Wformat-literal
warning, I found a rather easy case where the warning could be
reduced, by getting rid of obsolete error-reporting practices.
This is the last place where we were passing the (unused) net
and conn arguments for constructing an error.

* src/util/virterror_internal.h (virErrorMsg): Delete prototype.
(virReportError): Delete macro.
* src/util/virterror.c (virErrorMsg): Make static.
* src/libvirt_private.syms (virterror_internal.h): Drop export.
* src/util/conf.c (virConfError): Convert to macro.
(virConfErrorHelper): New function, and adjust error calls.
* src/xen/xen_hypervisor.c (virXenErrorFunc): Delete.
(xenHypervisorGetSchedulerType)
(xenHypervisorGetSchedulerParameters)
(xenHypervisorSetSchedulerParameters)
(xenHypervisorDomainBlockStats)
(xenHypervisorDomainInterfaceStats)
(xenHypervisorDomainGetOSType)
(xenHypervisorNodeGetCellsFreeMemory, xenHypervisorGetVcpus):
Update callers.

Reusing common code makes things smaller; it also buys us some
additional safety, such as now rejecting duplicate parameters
during a set operation.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters)
(qemuDomainSetMemoryParameters, qemuDomainSetNumaParameters)
(qemuSetSchedulerParametersFlags)
(qemuDomainSetInterfaceParameters, qemuDomainSetBlockIoTune)
(qemuDomainGetBlkioParameters, qemuDomainGetMemoryParameters)
(qemuDomainGetNumaParameters, qemuGetSchedulerParametersFlags)
(qemuDomainBlockStatsFlags, qemuDomainGetInterfaceParameters)
(qemuDomainGetBlockIoTune): Use new helpers.
* src/esx/esx_driver.c (esxDomainSetSchedulerParametersFlags)
(esxDomainSetMemoryParameters)
(esxDomainGetSchedulerParametersFlags)
(esxDomainGetMemoryParameters): Likewise.
* src/libxl/libxl_driver.c
(libxlDomainSetSchedulerParametersFlags)
(libxlDomainGetSchedulerParametersFlags): Likewise.
* src/lxc/lxc_driver.c (lxcDomainSetMemoryParameters)
(lxcSetSchedulerParametersFlags, lxcDomainSetBlkioParameters)
(lxcDomainGetMemoryParameters, lxcGetSchedulerParametersFlags)
(lxcDomainGetBlkioParameters): Likewise.
* src/test/test_driver.c (testDomainSetSchedulerParamsFlags)
(testDomainGetSchedulerParamsFlags): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorSetSchedulerParameters)
(xenHypervisorGetSchedulerParameters): Likewise.

pciTrySecondaryBusReset checks if there is active device on the
same bus, however, qemu driver doesn't maintain an effective
list for the inactive devices, and it passes meaningless argument
for parameter "inactiveDevs". e.g. (qemuPrepareHostdevPCIDevices)

if (!(pcidevs = qemuGetPciHostDeviceList(hostdevs, nhostdevs)))
    return -1;

..skipped...

if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0)
    goto reattachdevs;

NB, the "pcidevs" used above are extracted from domain def, and
thus one won't be able to attach a device of which bus has other
device even detached from host (nodedev-detach). To see more
details of the problem:

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=773667

This patch is to resolve the problem by introducing an inactive
PCI device list (just like qemu_driver->activePciHostdevs), and
the whole logic is:

  * Add the device to inactive list during nodedev-dettach
  * Remove the device from inactive list during nodedev-reattach
  * Remove the device from inactive list during attach-device
    (for non-managed device)
  * Add the device to inactive list after detach-device, only
    if the device is not managed

With the above, we have a sufficient inactive PCI device list, and thus
we can use it for pciResetDevice. e.g.(qemuPrepareHostdevPCIDevices)

if (pciResetDevice(dev, driver->activePciHostdevs,
                   driver->inactivePciHostdevs) < 0)
    goto reattachdevs;

xen-unstable c/s 23874:651aed73b39c added another member to
xen_domctl_getdomaininfo struct and bumped domctl version to 8.
Add a corresponding domctl v8 struct in xen hypervisor sub-driver
and detect domctl v8 during initialization.

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.

The lifetime of the virDomainEventState object is tied to
the lifetime of the driver, which in stateless drivers is
tied to the lifetime of the virConnectPtr.

If we add & remove a timer when allocating/freeing the
virDomainEventState object, we can get a situation where
the timer still triggers once after virDomainEventState
has been freed. The timeout callback can't keep a ref
on the event state though, since that would be a circular
reference.

The trick is to only register the timer when a callback
is registered with the event state & remove the timer
when the callback is unregistered.

The demo for the bug is to run

  while true ; do date ; ../tools/virsh -q -c test:///default 'shutdown test; undefine test; dominfo test' ; done

prior to this fix, it will frequently hang and / or
crash, or corrupt memory

Currently all drivers using domain events need to provide a callback
for handling a timer to dispatch events in a clean stack. There is
no technical reason for dispatch to go via driver specific code. It
could trivially be dispatched directly from the domain event code,
thus removing tedious boilerplate code from all drivers

Also fix the libxl & xen drivers to pass 'true' when creating the
virDomainEventState, since they run inside the daemon & thus always
expect events to be present.

* src/conf/domain_event.c, src/conf/domain_event.h: Internalize
  dispatch of events from timer callback
* src/libxl/libxl_driver.c, src/lxc/lxc_driver.c,
  src/qemu/qemu_domain.c, src/qemu/qemu_driver.c,
  src/remote/remote_driver.c, src/test/test_driver.c,
  src/uml/uml_driver.c, src/vbox/vbox_tmpl.c,
  src/xen/xen_driver.c: Remove all timer dispatch functions

* src/libxl/libxl_driver.c, src/lxc/lxc_driver.c,
  src/qemu/qemu_driver.c, src/remote/remote_driver.c,
  src/test/test_driver.c, src/uml/uml_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Convert
  to threadsafe APIs

When registering a callback for a particular event some callers
need to know how many callbacks already exist for that event.
While it is possible to ask for a count, this is not free from
race conditions when threaded. Thus the API for registering
callbacks should return the count of callbacks. Also rename
virDomainEventStateDeregisterAny to virDomainEventStateDeregisterID

* src/conf/domain_event.c, src/conf/domain_event.h,
  src/libvirt_private.syms: Return count of callbacks when
  registering callbacks
* src/libxl/libxl_driver.c, src/libxl/libxl_driver.c,
  src/qemu/qemu_driver.c, src/remote/remote_driver.c,
  src/remote/remote_driver.c, src/uml/uml_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Update
  for change in APIs

The Xen & VBox drivers deal with callbacks & dispatching of
events directly. All the other drivers use a timer to dispatch
events from a clean stack state, rather than deep inside the
drivers. Convert Xen & VBox over to virDomainEventState so
that they match behaviour of other drivers

* src/conf/domain_event.c: Return count of remaining
  callbacks when unregistering event callback
* src/vbox/vbox_tmpl.c, src/xen/xen_driver.c,
  src/xen/xen_driver.h: Convert to virDomainEventState

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.

Many of these were mentioned by Yuri Chornoivan in:
https://bugzilla.redhat.com/show_bug.cgi?id=669506

* src/esx/esx_vi.c (esxVI_WaitForTaskCompletion): Fix spelling.
* src/conf/netdev_vport_profile_conf.c
(virNetDevVPortProfileParse): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainSetVcpusFlags):
Likewise.
* src/xen/xm_internal.c (xenXMDomainSetVcpusFlags): Likewise.
* src/esx/esx_util.c (esxUtil_ResolveHostname): Likewise.
* src/storage/storage_backend_fs.c
(virStorageBackendFileSystemBuild): Likewise.
* daemon/libvirtd.conf: Likewise.
* src/util/logging.c (virLogMessage): Likewise.
* src/uml/uml_conf.c (umlBuildCommandLineNet): Likewise.
* src/vmx/vmx.c (virVMXFormatEthernet): Likewise.

* src/lxc/lxc_conf.c, src/uml/uml_conf.c,
  src/xen/xen_hypervisor.c: Initialize suspend capabilities
* tests/xencapsdata/*xml: Add empty powermgmt capabilities

Add the core functions that implement the functionality of the API.
Suspend is done by using an asynchronous mechanism so that we can return
the status to the caller before the host gets suspended. This asynchronous
operation is achieved by suspending the host in a separate thread of
execution. However, returning the status to the caller is only best-effort,
but not guaranteed.

To resume the host, an RTC alarm is set up (based on how long we want to
suspend) before suspending the host. When this alarm fires, the host
gets woken up.

Suspend-to-RAM operation on a host running Linux can take upto more than 20
seconds, depending on the load of the system. (Freezing of tasks, an operation
preceding any suspend operation, is given up after a 20 second timeout).
And Suspend-to-Disk can take even more time, considering the time required
for compaction, creating the memory image and writing it to disk etc.
So, we do not allow the user to specify a suspend duration of less than 60
seconds, to be on the safer side, since we don't want to prematurely declare
failure when we only had to wait for some more time.

None of the callers cared if str was updated to point to the next
byte after the parsed cpuset; simplifying this results in quite
a few code simplifications.  Additionally, virCPUDefParseXML was
strdup()'ing a malloc()'d string; avoiding a memory copy resulted
in less code.

* src/conf/domain_conf.h (virDomainCpuSetParse): Alter signature.
* src/conf/domain_conf.c (virDomainCpuSetParse): Don't modify str.
(virDomainVcpuPinDefParseXML, virDomainDefParseXML): Adjust
callers.
* src/conf/cpu_conf.c (virCPUDefParseXML): Likewise.
* src/xen/xend_internal.c (sexpr_to_xend_topology): Likewise.
* src/xen/xm_internal.c (xenXMDomainPinVcpu): Likewise.
* src/xenxs/xen_sxpr.c (xenParseSxpr): Likewise.
* src/xenxs/xen_xm.c (xenParseXM): Likewise.

The default console type may vary based on the OS type. ie a Xen
paravirt guests wants a 'xen' console, while a fullvirt guests
wants a 'serial' console.

A plain integer default console type in the capabilities does
not suffice. Instead introduce a callback that is passed the
OS type.

* src/conf/capabilities.h: Use a callback for default console
  type
* src/conf/domain_conf.c, src/conf/domain_conf.h: Use callback
  for default console type. Add missing LXC/OpenVZ console types.
* src/esx/esx_driver.c, src/libxl/libxl_conf.c,
  src/lxc/lxc_conf.c, src/openvz/openvz_conf.c,
  src/phyp/phyp_driver.c, src/qemu/qemu_capabilities.c,
  src/uml/uml_conf.c, src/vbox/vbox_tmpl.c,
  src/vmware/vmware_conf.c, src/xen/xen_hypervisor.c,
  src/xenapi/xenapi_driver.c: Set default console type callback

While Xen only has a single paravirt console, UML, and
QEMU both support multiple paravirt consoles. The LXC
driver can also be trivially made to support multiple
consoles. This patch extends the XML to allow multiple
<console> elements in the XML. It also makes the UML
and QEMU drivers support this config.

* src/conf/domain_conf.c, src/conf/domain_conf.h: Allow
  multiple <console> devices
* src/lxc/lxc_driver.c, src/xen/xen_driver.c,
  src/xenxs/xen_sxpr.c, src/xenxs/xen_xm.c: Update for
  internal API changes
* src/security/security_selinux.c, src/security/virt-aa-helper.c:
  Only label consoles that aren't a copy of the serial device
* src/qemu/qemu_command.c, src/qemu/qemu_driver.c,
  src/qemu/qemu_process.c, src/uml/uml_conf.c,
  src/uml/uml_driver.c: Support multiple console devices
* tests/qemuxml2xmltest.c, tests/qemuxml2argvtest.c: Extra
  tests for multiple virtio consoles. Set QEMU_CAPS_CHARDEV
  for all console /channel tests
* tests/qemuxml2argvdata/qemuxml2argv-channel-virtio-auto.args,
  tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.args
  tests/qemuxml2argvdata/qemuxml2argv-console-virtio.args: Update
  for correct chardev syntax
* tests/qemuxml2argvdata/qemuxml2argv-console-virtio-many.args,
  tests/qemuxml2argvdata/qemuxml2argv-console-virtio-many.xml: New
  test file

Allow the user to call with nparams too small, per API documentation.

* src/xen/xen_hypervisor.c (xenHypervisorGetSchedulerParameters):
Allow fewer than max.
* src/xen/xend_internal.c (xenDaemonGetSchedulerParameters):
Likewise.

Document the parameter names that will be used by
virDomain{Get,Set}SchedulerParameters{,Flags}, rather than
hard-coding those names in each driver, to match what is
done with memory, blkio, and blockstats parameters.

* include/libvirt/libvirt.h.in (VIR_DOMAIN_SCHEDULER_CPU_SHARES)
(VIR_DOMAIN_SCHEDULER_VCPU_PERIOD)
(VIR_DOMAIN_SCHEDULER_VCPU_QUOTA, VIR_DOMAIN_SCHEDULER_WEIGHT)
(VIR_DOMAIN_SCHEDULER_CAP, VIR_DOMAIN_SCHEDULER_RESERVATION)
(VIR_DOMAIN_SCHEDULER_LIMIT, VIR_DOMAIN_SCHEDULER_SHARES): New
field name macros.
* src/qemu/qemu_driver.c (qemuSetSchedulerParametersFlags)
(qemuGetSchedulerParametersFlags): Use new defines.
* src/test/test_driver.c (testDomainGetSchedulerParamsFlags)
(testDomainSetSchedulerParamsFlags): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorGetSchedulerParameters)
(xenHypervisorSetSchedulerParameters): Likewise.
* src/xen/xend_internal.c (xenDaemonGetSchedulerParameters)
(xenDaemonSetSchedulerParameters): Likewise.
* src/lxc/lxc_driver.c (lxcSetSchedulerParametersFlags)
(lxcGetSchedulerParametersFlags): Likewise.
* src/esx/esx_driver.c (esxDomainGetSchedulerParametersFlags)
(esxDomainSetSchedulerParametersFlags): Likewise.
* src/libxl/libxl_driver.c (libxlDomainGetSchedulerParametersFlags)
(libxlDomainSetSchedulerParametersFlags): Likewise.

This adds support for a libvirt client configuration file
either /etc/libvirt/libvirt.conf for privileged clients,
or $HOME/.libvirt/libvirt.conf for unprivileged clients.

It allows one parameter

 uri_aliases = [
   "hail=qemu+ssh://root@hail.cloud.example.com/system",
   "sleet=qemu+ssh://root@sleet.cloud.example.com/system",
 ]

Any call to virConnectOpen with a non-NULL URI will first
attempt to match against the uri_aliases list. An application
can disable this by using VIR_CONNECT_NO_ALIASES

* docs/uri.html.in: Document URI aliases
* include/libvirt/libvirt.h.in: Add VIR_CONNECT_NO_ALIASES
* libvirt.spec.in, mingw32-libvirt.spec.in: Add /etc/libvirt/libvirt.conf
* src/Makefile.am: Install default config file
* src/libvirt.c: Add support for URI aliases
* src/remote/remote_driver.c: Don't try to handle URIs
  with no scheme and which clearly are not paths
* src/util/conf.c: Don't raise error on virConfFree(NULL)
* src/xen/xen_driver.c: Don't raise error on URIs
  with no scheme

virInitialize() → xenRegister() → xenhypervisorInit() determines the
version of the Hypervisor. This breaks xencapstest when building as root
on a dom0 system, since xenHypervisorBuildCapabilities() adds the "hap"
and "viridian" features based on the detected version.

Add an optional parameter to xenhypervisorInit() to disable automatic
detection of the Hypervisor version. The passed in arguments are used
instead.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

Calling virInitialize() → xenRegister() → xenhypervisorInit() directly
opens a connection to the Xen Hypervisor, which breaks some unit tests.

Move all static variables into a struct to make it easier to override
them when testing.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

The next patch will add a syntax check that flags this usage in xen
as awkward - while it was valid memory management, it was very hard
to maintain.  Swapping to a more traditional allocation may be a bit
slower, but easier to understand.

* src/xen/xend_internal.c (xenDaemonListDomainsOld): Use two-level
allocation, rather than abusing allocation function.
(xenDaemonLookupByUUID): Update caller.

/usr/lib/stdlib.h in Mac OS X and probably also in BSD's
exports this symbol :(

'+' in strings get translated to ' ' when editing domains.
While xenDaemonDomainCreateXML() did URL-escape the sexpr,
xenDaemonDomainDefineXML() did not.

Remove the explicit urlencode() in xenDaemonDomainCreateXML() and add
the direct encoding calls to xend_op_ext() because it calls xend_post()
which uses "Content-Type: application/x-www-form-urlencoded". According
to <http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.1> this
requires all parameters to be url-encoded as specified in rfc1738.

Notice: virBufferAsprintf(..., "%s=%s", ...) is again replaced by three
calls to virBufferURIEncodeString() and virBufferAddChar() because '='
is a "reserved" character, which would get escaped by
virBufferURIEncodeString(), which - by the way - escapes anything not
c_isalnum().
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

I got confused when 'virsh domblkinfo dom disk' required the
path to a disk (which can be ambiguous, since a single file
can back multiple disks), rather than the unambiguous target
device name that I was using in disk snapshots.  So, in true
developer fashion, I went for the best of both worlds - all
interfaces that operate on a disk (aka block) now accept
either the target name or the unambiguous path to the backing
file used by the disk.

* src/conf/domain_conf.h (virDomainDiskIndexByName): Add
parameter.
(virDomainDiskPathByName): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainDiskIndexByName): Also allow
searching by path, and decide whether ambiguity is okay.
(virDomainDiskPathByName): New function.
(virDomainDiskRemoveByName, virDomainSnapshotAlignDisks): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainBlockPeek)
(qemuDomainAttachDeviceConfig, qemuDomainUpdateDeviceConfig)
(qemuDomainGetBlockInfo, qemuDiskPathToAlias): Likewise.
* src/qemu/qemu_process.c (qemuProcessFindDomainDiskByPath):
Likewise.
* src/libxl/libxl_driver.c (libxlDomainAttachDeviceDiskLive)
(libxlDomainDetachDeviceDiskLive, libxlDomainAttachDeviceConfig)
(libxlDomainUpdateDeviceConfig): Likewise.
* src/uml/uml_driver.c (umlDomainBlockPeek): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainBlockPeek): Likewise.
* docs/formatsnapshot.html.in: Update documentation.
* tools/virsh.pod (domblkstat, domblkinfo): Likewise.
* docs/schemas/domaincommon.rng (diskTarget): Tighten pattern on
disk targets.
* docs/schemas/domainsnapshot.rng (disksnapshot): Update to match.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: Update test.

On systems with many pcpus, the sexpr returned by xend can be quite
large for dom0 when it is configured to have #vcpus = #pcpus (default).
E.g. on a 80 pcpu system, where dom0 had 80 vcpus, the sexpr details
for dom0 was 73817 bytes!  Increase maximum buffer size to 256k.

xenDaemonDomainFetch() was overwriting errors reported by
xend_get() and xend_req().  E.g. without patch

error: failed Xen syscall xenDaemonDomainFetch failed to find this domain

with patch

error: internal error Xend returned HTTP Content-Length of 73817, which exceeds
maximum of 65536