When libxl registers an FD with the libxl driver, the refcnt of the
associated libxlDomainObjPrivate object is incremented. The refcnt
is decremented when libxl deregisters the FD.  But some FDs are only
deregistered when their libxl ctx is freed, which unfortunately is
done in the libxlDomainObjPrivate dispose function.  With references
held by the FDs, libxlDomainObjPrivate is never disposed.

I added the ref/unref in FD registration/deregistration when adding
the same in timer registration/deregistration.  For timers, this
is a simple approach to ensuring the libxlDomainObjPrivate is not
disposed prior to their expirtation, which libxl guarantees will
occur.  It is not needed for FDs, and only causes
libxlDomainObjPrivate to leak.

This patch removes the reference on libxlDomainObjPrivate for FD
registrations, but retains them for timer registrations.  Tested on
the latest releases of Xen supported by the libxl driver:  4.2.3,
4.3.1, and 4.4.0 RC3.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

there is a segfault in libxl logging in libxl_ctx_free when domain
create fail. because the log output handler vmessage is freed by
xtl_logger_destroy before libxl_ctx_free in virDomainObjListRemove.
move xtl_logger_destroy after libxl_ctx_free could fix this bug.
Signed-off-by: NBamvor Jian Zhang <bjzhang@suse.com>

'const fooPtr' is the same as 'foo * const' (the pointer won't
change, but it's contents can).  But in general, if an interface
is trying to be const-correct, it should be using 'const foo *'
(the pointer is to data that can't be changed).

Fix up offenders in src/conf/domain_conf, and their fallout.

Several things to note: virObjectLock() requires a non-const
argument; if this were C++, we could treat the locking field
as 'mutable' and allow locking an otherwise 'const' object, but
that is a more invasive change, so I instead dropped attempts
to be const-correct on domain lookup.  virXMLPropString and
friends require a non-const xmlNodePtr - this is because libxml2
is not a const-correct library.  We could make the src/util/virxml
wrappers cast away const, but I figured it was easier to not
try to mark xmlNodePtr as const.  Finally, virDomainDeviceDefCopy
was a rather hard conversion - it calls virDomainDeviceDefPostParse,
which in turn in the xen driver was actually modifying the domain
outside of the current device being visited.  We should not be
adding a device on the first per-device callback, but waiting until
after all per-device callbacks are complete.

* src/conf/domain_conf.h (virDomainObjListFindByID)
(virDomainObjListFindByUUID, virDomainObjListFindByName)
(virDomainObjAssignDef, virDomainObjListAdd): Drop attempt at
const.
(virDomainDeviceDefCopy): Use intended type.
(virDomainDeviceDefParse, virDomainDeviceDefPostParseCallback)
(virDomainVideoDefaultType, virDomainVideoDefaultRAM)
(virDomainChrGetDomainPtrs): Make const-correct.
* src/conf/domain_conf.c (virDomainObjListFindByID)
(virDomainObjListFindByUUID, virDomainObjListFindByName)
(virDomainDeviceDefCopy, virDomainObjListAdd)
(virDomainObjAssignDef, virDomainHostdevSubsysUsbDefParseXML)
(virDomainHostdevSubsysPciOrigStatesDefParseXML)
(virDomainHostdevSubsysPciDefParseXML)
(virDomainHostdevSubsysScsiDefParseXML)
(virDomainControllerModelTypeFromString)
(virDomainTPMDefParseXML, virDomainTimerDefParseXML)
(virDomainSoundCodecDefParseXML, virDomainSoundDefParseXML)
(virDomainWatchdogDefParseXML, virDomainRNGDefParseXML)
(virDomainMemballoonDefParseXML, virDomainNVRAMDefParseXML)
(virSysinfoParseXML, virDomainVideoAccelDefParseXML)
(virDomainVideoDefParseXML, virDomainHostdevDefParseXML)
(virDomainRedirdevDefParseXML)
(virDomainRedirFilterUsbDevDefParseXML)
(virDomainRedirFilterDefParseXML, virDomainIdMapEntrySort)
(virDomainIdmapDefParseXML, virDomainVcpuPinDefParseXML)
(virDiskNameToBusDeviceIndex, virDomainDeviceDefCopy)
(virDomainVideoDefaultType, virDomainHostdevAssignAddress)
(virDomainDeviceDefPostParseInternal, virDomainDeviceDefPostParse)
(virDomainChrGetDomainPtrs, virDomainControllerSCSINextUnit)
(virDomainSCSIDriveAddressIsUsed)
(virDomainDriveAddressIsUsedByDisk)
(virDomainDriveAddressIsUsedByHostdev): Fix fallout.
* src/openvz/openvz_driver.c (openvzDomainDeviceDefPostParse):
Likewise.
* src/libxl/libxl_domain.c (libxlDomainDeviceDefPostParse):
Likewise.
* src/qemu/qemu_domain.c (qemuDomainDeviceDefPostParse)
(qemuDomainDefaultNetModel): Likewise.
* src/lxc/lxc_domain.c (virLXCDomainDeviceDefPostParse):
Likewise.
* src/uml/uml_driver.c (umlDomainDeviceDefPostParse): Likewise.
* src/xen/xen_driver.c (xenDomainDeviceDefPostParse): Split...
(xenDomainDefPostParse): ...since per-device callback is not the
time to be adding a device.
Signed-off-by: NEric Blake <eblake@redhat.com>

Create libxl_domain.[ch] and move all functions operating on
libxlDomainObjPrivate to these files.  This will be useful for
future patches that e.g. add job support for libxlDomainObjPrivate.