Implementation of Domain{Attach,Detach}DeviceFlags in remote driver.

Definition of wire protocol format for
virDomain{Attach,Detach}DeviceFlags.

Implementation of public API for virDomain{Attach,Detach}DeviceFlags.

V2: Don't break remote compatibility with older libvirtd

Definition of internal API for virDomain{Attach,Detach}DeviceFlags.

Definition of public API for virDomain{Attach,Detach}DeviceFlags.

V2: Adjust libvrt_public.syms to anticipated 0.7.7 release.

virDomain{Attach,Detach}Device is now only permitted on active
domains.  Explicitly state this restriction in the API
documentation.

V2: Only change doc, dropping the hunk that forced the restriction
    in libvirt frontend.

When configured with --enable-gcc-warnings, it didn't even compile.
* src/util/storage_file.c: Include <assert.h>.
(absolutePathFromBaseFile): Assert that converting size_t to int is valid.
Reverse length/string args to match "%.*s".
Explicitly ignore the return value of virAsprintf.

* src/util/storage_file.c: Include "dirname.h".
(absolutePathFromBaseFile): Rewrite not to leak, and to require
fewer allocations.
* bootstrap (modules): Add dirname-lgpl.
* .gnulib: Update submodule to the latest.

* src/xen/sexpr.c (sexpr_string): Free sexpr buffer upon allocation
failure.

* src/conf/domain_conf.c (virDomainChrDefParseXML): Don't leak a
virDomainChrDef buffer upon "unknown target type for char device" error.

* src/util/util.c (virExecWithHook): Free argv_str string before
returning upon failure to allocate space for environment.

* src/util/cgroup.c (virCgroupDetectPlacement): Close the mapping
FILE* also upon error.

* src/util/cgroup.c (virCgroupCpuSetInherit) [HAVE_MNTENT_H]:
Don't leak CPU-set inheritance value strings.

When restoring from a saved guest image, the XML would already
contain the PCI slot ID of the IDE controller & video card.
The attempt to explicitly reserve this upfront would thus fail
everytime.

* src/qemu/qemu_conf.c: Reserve IDE controller / video card
  slot at time of need, rather than upfront

Similar fix as previous one but for fork() usage when creating
a file or directory

* src/util/util.c: virLogLock() and virLogUnlock() around fork()
  in virFileCreate() and virDirCreateSimple()

Ad pointed out by Dan Berrange:
So if some thread in libvirtd is currently executing a logging call,
while another thread calls virExec(), that other thread no longer
exists in the child, but its lock is never released. So when the
child then does virLogReset() it deadlocks.

The only way I see to address this, is for the parent process to call
virLogLock(), immediately before fork(), and then virLogUnlock()
afterwards in both parent & child. This will ensure that no other
thread
can be holding the lock across fork().

* src/util/logging.[ch] src/libvirt_private.syms: export virLogLock() and
  virLogUnlock()
* src/util/util.c: lock just before forking and unlock just after - in
  both parent and child.

The original udev node device backend neglected to lock the driverState
struct containing the device list when adding and removing devices
* src/node_device/node_device_udev.c: add necessary locks in
  udevRemoveOneDevice() and udevAddOneDevice()

* src/conf/interface_conf.c (virInterfaceDefParseProtoIPv4): If
virXPathNodeSet returns -1, indicate failure by returning -1 right away.
(virInterfaceDefParseProtoIPv6): Likewise.

* src/conf/storage_conf.c (virStoragePoolSourceListNewSource):
Remove an unused (and leaked) allocation.

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

If the primary security driver (SELinux/AppArmour) was disabled
then the secondary QEMU DAC security driver was also disabled.
This is mistaken, because the latter must be active at all times

* src/qemu/qemu_driver.c: Ensure DAC driver is always active

* src/xen/xen_hypervisor.c: Remove all "domain == NULL" tests.
* src/xen/xen_hypervisor.h: Instead, use ATTRIBUTE_NONNULL to
mark each "domain" parameter as "known always to be non-NULL".

* src/xen/xen_hypervisor.c (xenHypervisorGetVcpus): Don't attempt
to diagnose an unlikely NULL-domain or NULL-domain->conn error.

When attaching a USB host device based on vendor/product, libvirt
will resolve the vendor/product into a device/bus pair. This means
that when printing XML we should allow device/bus info to be printed
at any time if present

* src/conf/domain_conf.c, docs/schemas/domain.rng: Allow USB device
  bus info alongside vendor/product

To allow devices to be hot(un-)plugged it is neccessary to ensure
they all have a unique device aliases. This fixes the hotplug
methods to assign device aliases before invoking the monitor
commands which need them

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Expose methods
  for assigning device aliases for disks, host devices and
  controllers
* src/qemu/qemu_driver.c: Assign device aliases when hotplugging
  all types of device
* tests/qemuxml2argvdata/qemuxml2argv-hostdev-pci-address-device.args,
  tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-address-device.args:
  Update for changed hostdev naming scheme

This patch re-arranges the QEMU device alias assignment code to
make it easier to call into the same codeblock when performing
device hotplug. The new code has the ability to skip over already
assigned names to facilitate hotplug

* src/qemu/qemu_driver.c: Call qemuAssignDeviceNetAlias()
  instead of qemuAssignNetNames
* src/qemu/qemu_conf.h: Export qemuAssignDeviceNetAlias()
  instead of qemuAssignNetNames
* src/qemu/qemu_driver.c: Merge the legacy disk/network alias
  assignment code into the main methods

The current way of assigning names to the host network backend and
NIC device in QEMU was over complicated, by varying naming scheme
based on the NIC model and backend type. This simplifies the naming
to simply be 'net0' and 'hostnet0', allowing code to easily determine
the host network name and vlan based off the primary device alias
name 'net0'. This in turn allows removal of alot of QEMU specific
code from the XML parser, and makes it easier to assign new unique
names for NICs that are hotplugged

* src/conf/domain_conf.c, src/conf/domain_conf.h: Remove hostnet_name
  and vlan fields from virNetworkDefPtr
* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h, src/qemu/qemu_driver.c:
  Use a single network alias naming scheme regardless of NIC type
  or backend type. Determine VLANs from the alias name.
* tests/qemuxml2argvdata/qemuxml2argv-net-eth-names.args,
  tests/qemuxml2argvdata/qemuxml2argv-net-virtio-device.args,
  tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.args: Update
  for new simpler naming scheme

The QEMU 0.12.x tree has the -netdev command line argument, but not
corresponding monitor command. We can't enable the former, without
the latter since it will break hotplug/unplug.

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Disable -netdev usage
  until 0.13 at earliest
* tests/qemuxml2argvtest.c: Add test for -netdev syntax
* tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.args,
  tests/qemuxml2argvdata/qemuxml2argv-net-virtio-netdev.xml: Test
  data files for -netdev syntax

PCI disk, disk controllers, net devices and host devices need to
have PCI addresses assigned before they are hot-plugged

* src/qemu/qemu_conf.c: Add APIs for ensuring a device has an
  address and releasing unused addresses
* src/qemu/qemu_driver.c: Ensure all devices have addresses
  when hotplugging.

The current QEMU code allocates PCI addresses incrementally starting
at 4. This is not satisfactory because the user may have given some
addresses in their XML config, which need to be skipped over when
allocating addresses to remaining devices.

It is thus neccessary to maintain a list of already allocated PCI
addresses and then only allocate ones that remain unused. This is
also required for domain device hotplug to work properly later.

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Add APIs for creating
  list of existing PCI addresses, and allocating new addresses.
  Refactor address assignment to use this code
* src/qemu/qemu_driver.c: Pull PCI address assignment up into the
  qemuStartVMDaemon() method, as a prelude to moving it into the
  'define' method. Update list of allocated addresses when connecting
  to a running VM at daemon startup.
* tests/qemuxml2argvtest.c, tests/qemuargv2xmltest.c,
  tests/qemuxml2xmltest.c: Remove USB product test since all
  passthrough is done based on address
* tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-product.args,
  tests/qemuxml2argvdata/qemuxml2argv-hostdev-usb-product.xml: Kil
  unused data files

The virDomainDeviceInfoIterate() function will provide a
convenient way to iterate over all devices in a domain.

* src/conf/domain_conf.c, src/conf/domain_conf.h,
  src/libvirt_private.syms: Add virDomainDeviceInfoIterate()
  function.

Since QEMU startup uses the new -device argument, the hotplug
code needs todo the same. This converts disk, network and
host device hotplug to use the device_add command

* src/qemu/qemu_driver.c: Use new device_add monitor APIs
  whereever possible

The way QEMU is started has been changed to use '-device' and
the new style '-drive' syntax. This needs to be mirrored in
the hotplug code, requiring addition of two new APIs.

* src/qemu/qemu_monitor.h, src/qemu/qemu_monitor.c: Define APIs
  qemuMonitorAddDevice() and qemuMonitorAddDrive()
* src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h:
  Implement the new monitor APIs

To allow for better code reuse from hotplug methods, the code for
generating PCI/USB hostdev arg values is split out into separate
methods

* qemu/qemu_conf.h, qemu/qemu_conf.c: Introduce new APis for
  qemuBuildPCIHostdevPCIDevStr, qemuBuildUSBHostdevUsbDevStr
  and qemuBuildUSBHostdevDevStr