When a domain is defined on host1, migrated to host2 and then migrated
back to host1, its current configuration would overwrite the libvirtd's
in-memory copy of persistent configuration of that domain. This is not
desired as we want to preserve the persistent configuration untouched.

This patch introduces new 'live' parameter to virDomainAssignDef.
Passing 'true' for 'live' means the configuration passed to
virDomainAssignDef describes a configuration of live instance of the
domain. This applies for saved domains which are being restored or for
incoming domains during migration.

All callers have been changed to pass the appropriate value.

The current virDomainAttachDevice API can be (ab)used to change
the media of an existing CDROM/Floppy device. Going forward there
will be more devices that can be configured on the fly and overloading
virDomainAttachDevice for this is not too pleasant. This patch adds
a new virDomainUpdateDeviceFlags() explicitly just for modifying
existing devices.

* include/libvirt/libvirt.h.in: Add virDomainUpdateDeviceFlags
* src/driver.h: Internal API for virDomainUpdateDeviceFlags
* src/libvirt.c, src/libvirt_public.syms: Glue public API to
  driver API
* src/esx/esx_driver.c, src/lxc/lxc_driver.c, src/opennebula/one_driver.c,
  src/openvz/openvz_driver.c, src/phyp/phyp_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, src/xenapi/xenapi_driver.c: Add
  stubs for new driver entry point

The libvirtd daemon impl will need to switch over to using the
new event APIs. To make this simpler, ensure all drivers currently
providing events support both the new APIs and old APIs.

* src/lxc/lxc_driver.c, src/qemu/qemu_driver.c, src/test/test_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Implement the new
  virConnectDomainEvent(Dereg|Reg)isterAny driver entry points

The internal domain events APIs are designed to handle the lifecycle
events. This needs to be refactored to allow arbitrary new event
types to be handled.

 * The signature of virDomainEventDispatchFunc changes to use
   virConnectDomainEventGenericCallback instead of the lifecycle
   event specific virConnectDomainEventCallback
 * Every registered callback gains a unique ID to allow its
   removal based on ID, instead of function pointer
 * Every registered callback gains an 'eventID' to allow callbacks
   for different types of events to be distinguished
 * virDomainEventDispatch is adapted to filter out callbacks
   whose eventID does not match the eventID of the event being
   dispatched
 * virDomainEventDispatch is adapted to filter based on the
   domain name and uuid, if this filter is set for a callback.
 * virDomainEvent type/detail fields are moved into a union to
   allow different data fields for other types of events to be
   added later

* src/conf/domain_event.h, src/conf/domain_event.c: Refactor
  to allow handling of different types of events
* src/lxc/lxc_driver.c, src/qemu/qemu_driver.c,
  src/remote/remote_driver.c, src/test/test_driver.c,
  src/xen/xen_driver.c: Change dispatch function signature
  to use virConnectDomainEventGenericCallback

The current API for domain events has a number of problems

 - Only allows for domain lifecycle change events
 - Does not allow the same callback to be registered multiple times
 - Does not allow filtering of events to a specific domain

This introduces a new more general purpose domain events API

  typedef enum {
     VIR_DOMAIN_EVENT_ID_LIFECYCLE = 0,       /* virConnectDomainEventCallback */
      ...more events later..
  }

  int virConnectDomainEventRegisterAny(virConnectPtr conn,
                                       virDomainPtr dom, /* Optional, to filter */
                                       int eventID,
                                       virConnectDomainEventGenericCallback cb,
                                       void *opaque,
                                       virFreeCallback freecb);

  int virConnectDomainEventDeregisterAny(virConnectPtr conn,
                                         int callbackID);

Since different event types can received different data in the callback,
the API is defined with a generic callback. Specific events will each
have a custom signature for their callback. Thus when registering an
event it is neccessary to cast the callback to the generic signature

eg

  int myDomainEventCallback(virConnectPtr conn,
                            virDomainPtr dom,
                            int event,
                            int detail,
                            void *opaque)
  {
    ...
  }

  virConnectDomainEventRegisterAny(conn, NULL,
                                   VIR_DOMAIN_EVENT_ID_LIFECYCLE,
                                   VIR_DOMAIN_EVENT_CALLBACK(myDomainEventCallback)
                                   NULL, NULL);

The VIR_DOMAIN_EVENT_CALLBACK() macro simply does a "bad" cast
to the generic signature

* include/libvirt/libvirt.h.in: Define new APIs for registering
  domain events
* src/driver.h: Internal driver entry points for new events APIs
* src/libvirt.c: Wire up public API to driver API for events APIs
* src/libvirt_public.syms: Export new APIs
* src/esx/esx_driver.c, src/lxc/lxc_driver.c, src/opennebula/one_driver.c,
  src/openvz/openvz_driver.c, src/phyp/phyp_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,
  src/xenapi/xenapi_driver.c: Stub out new API entries

* cfg.mk (useless_free_options): Add virDomainDefFree to the list
of free-like functions.
* src/test/test_driver.c (testDomainCreateXML): Remove useless-if-
before-virDomainDefFree.
* src/conf/domain_conf.c (virDomainAssignDef): Likewise

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.

This provides the internal glue for the driver API

* src/driver.h: Internal API contract
* src/libvirt.c, src/libvirt_public.syms: Connect public API
  to driver API
* src/esx/esx_driver.c, src/lxc/lxc_driver.c, src/opennebula/one_driver.c,
  src/openvz/openvz_driver.c, src/phyp/phyp_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: Stub out entry points

The internal glue layer for the new pubic API

* src/driver.h: Define internal driver API contract
* src/libvirt.c, src/libvirt_public.syms: Wire up public
  API to internal driver API
* src/esx/esx_driver.c, src/lxc/lxc_driver.c, src/opennebula/one_driver.c,
  src/openvz/openvz_driver.c, src/phyp/phyp_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: Stub new entry point

* src/conf/storage_conf.c (virStoragePoolDefParseSourceString):
* src/storage/storage_backend_fs.c:
(virStorageBackendFileSystemNetFindPoolSourcesFunc):
(virStorageBackendFileSystemNetFindPoolSources):
* src/test/test_driver.c (testStorageFindPoolSources):

Having some value in capabilities helps testing this stuff in
virt-manager.

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in interface_conf.{h,c} and update all callers to
match

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in storage_conf.{h,c} and storage_encryption_conf.{h,c}
and update all callers to match

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in node_device_conf.{h,c} and update all callers to
match

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in network_conf.{h,c} and update all callers to
match

It was used for error reporting only.

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

Set up the types for the domainMemoryStats function and insert it into the
virDriver structure definition.  Because of static initializers, update
every driver and set the new field to NULL.

* include/libvirt/libvirt.h.in: new API
* src/driver.h src/*/*_driver.c src/vbox/vbox_tmpl.c: add the new
  entry to the driver structure
* python/generator.py: fix compiler errors, the actual python binding is
  implemented later

* src/driver.h: add an extra entry point in the structure
* src/esx/esx_driver.c src/lxc/lxc_driver.c src/opennebula/one_driver.c
  src/openvz/openvz_driver.c src/phyp/phyp_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: add NULL entry points for
  all drivers

This patch adds the --crash option (already present in "xm dump-core")
to "virsh dump".  virDomainCoreDump already has a flags argument, so
the API/ABI is untouched.

* include/libvirt/libvirt.h.in (virDomainCoreDumpFlags): New flag for
  CoreDump
* src/test/test_driver.c (testDomainCoreDump): Do not crash
  after dump unless VIR_DUMP_CRASH is given.
* src/qemu/qemu_driver.c (qemudDomainCoreDump): Shutdown the domain
  instead of restarting it if --crash is passed.
* src/xen/xend_internal.c (xenDaemonDomainCoreDump): Support --crash.
* tools/virsh.c (opts_dump): Add --crash.
  (cmdDump): Map it to flags for virDomainCoreDump and pass them.

* src/test/test_driver.c: Fix leak of vcpu info, and nodedevice
  info

There is currently no way to determine the libvirt version of a remote
libvirtd we are connected to. This is a useful piece of data to enable
feature detection.

This implements the virConnectIsSecure, virConnectIsEncrypted,
virDomainIsPersistent, virDomainIsActive, virNetworkIsActive,
virNetworkIsPersistent, virStoragePoolIsActive,
virStoragePoolIsPersistent, virInterfaceIsActive APIs in
(nearly) all drivers. Exceptions are:

 phyp: missing domainIsActive/Persistent
 esx: missing domainIsPersistent
 opennebula: missing domainIsActive/Persistent

* src/remote/remote_protocol.x: Define remote wire ABI for newly
  added APIs.
* daemon/remote_dispatch*.h: Re-generated from remote_protocol.x
* src/esx/esx_driver.c, src/lxc/lxc_driver.c, src/network/bridge_driver.c,
  src/opennebula/one_driver.c, src/openvz/openvz_conf.c,
  src/openvz/openvz_driver.c, src/phyp/phyp_driver.c,
  src/remote/remote_driver.c, src/storage/storage_driver.c,
  src/test/test_driver.c, src/uml/uml_driver.c, src/vbox/vbox_tmpl.c,
  src/xen/xen_driver.c, src/xen/xen_driver.h, src/xen/xen_inotify.c,
  src/xen/xen_inotify.h: Implement all the new APIs where possible

Introduce a number of new APIs to  expose some boolean properties
of objects, which cannot otherwise reliably determined, nor are
aspects of the XML configuration.

 * virDomainIsActive: Checking virDomainGetID is not reliable
   since it is not possible to distinguish between error condition
   and inactive domain for ID of -1.
 * virDomainIsPersistent: Check whether a persistent config exists
   for the domain

 * virNetworkIsActive: Check whether the network is active
 * virNetworkIsPersistent: Check whether a persistent config exists
   for the network

 * virStoragePoolIsActive: Check whether the storage pool is active
 * virStoragePoolIsPersistent: Check whether a persistent config exists
   for the storage pool

 * virInterfaceIsActive: Check whether the host interface is active

 * virConnectIsSecure: whether the communication channel to the
   hypervisor is secure
 * virConnectIsEncrypted: whether any network based commnunication
   channels are encrypted

NB, a channel can be secure, even if not encrypted, eg if it does
not involve the network, like a UNIX socket, or pipe.

 * include/libvirt/libvirt.h.in: Define public API
 * src/driver.h: Define internal driver API
 * src/libvirt.c: Implement public API entry point
 * src/libvirt_public.syms: Export API symbols
 * src/esx/esx_driver.c, src/lxc/lxc_driver.c,
   src/interface/netcf_driver.c, src/network/bridge_driver.c,
   src/opennebula/one_driver.c, src/openvz/openvz_driver.c,
   src/phyp/phyp_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: Stub out driver tables

Use this function in the qemu, uml, lxc, and test drivers.

This matches the expected behavior of state drivers such as QEMU.

Performs changes needed when stopping a VM (which are currently duplicated
in several places, and forgotten in others).

This should be a no op for now, but we will use this function to set up
transient state in the future.

- Implement DomainGetMaxVCPUs
- Use GetMaxVCPUs to validate requested CPU amount
- Deny the 'hotplug' for a running domain.

All drivers have copy + pasted inadequate error reporting which wraps
util.c:virGetHostname. Move all error reporting to this function, and improve
what we report.

Changes from v1:
  Drop the driver wrappers around virGetHostname. This means we still need
  to keep the new conn argument to virGetHostname, but I think it's worth
  it.