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

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.

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

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>

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

Revert 6a1f5f56.  Now that libvirt_iohelper takes fds by
inheritance rather than by open() (commit 1eb66479), there is
no longer a race where the parent can unlink() a file prior to
the iohelper open()ing the same file.  From there, it makes
more sense to have the callers both create and unlink, rather
than the caller create and the stream unlink, since the latter
was only needed when iohelper had to do the unlink.

* src/fdstream.h (virFDStreamOpenFile, virFDStreamCreateFile):
Callers are responsible for deletion.
* src/fdstream.c (virFDStreamOpenFileInternal): Don't leak created
file on failure.
(virFDStreamOpenFile, virFDStreamCreateFile): Drop parameter.
* src/lxc/lxc_driver.c (lxcDomainOpenConsole): Update callers.
* src/qemu/qemu_driver.c (qemuDomainScreenshot)
(qemuDomainOpenConsole): Likewise.
* src/storage/storage_driver.c (storageVolumeDownload)
(storageVolumeUpload): Likewise.
* src/uml/uml_driver.c (umlDomainOpenConsole): Likewise.
* src/vbox/vbox_tmpl.c (vboxDomainScreenshot): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainOpenConsole): Likewise.

No need to use a for loop if we know there is exactly one client.
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 used exactly once.  The next patch will ensure that we
don't reintroduce uses of these callbacks.

* src/xen/xen_driver.c (xenUnifiedClose): Call close
unconditionally, to match xenUnifiedOpen.
(xenUnifiedNodeGetInfo, xenUnifiedDomainCreateXML)
(xenUnifiedDomainSave, xenUnifiedDomainRestore)
(xenUnifiedDomainCoreDump, xenUnifiedDomainUpdateDeviceFlags):
Make direct call to lone implementation.
* src/xen/xend_internal.h (xenDaemonDomainCoreDump)
(xenDaemonUpdateDeviceFlags, xenDaemonCreateXML): Add prototypes.
* src/xen/xend_internal.c (xenDaemonDomainCoreDump)
(xenDaemonUpdateDeviceFlags, xenDaemonCreateXML): Export.

The callback struct is great when iterating through several
possibilities, but when calling a known callback, it's just
overhead.  We can make the direct call in those cases.

* src/xen/xen_driver.c (xenUnifiedOpen, xenUnifiedDomainSuspend)
(xenUnifiedDomainResume, xenUnifiedDomainDestroyFlags): Make
direct calls instead of going through callback.

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.

Now that virDomainSetVcpusFlags knows about VIR_DOMAIN_AFFECT_CURRENT,
so should virDomainGetVcpusFlags.

Unfortunately, the virsh counterpart 'virsh vcpucount' has already
commandeered --current for a different meaning, so teaching virsh
to expose this in the next patch will require a bit of care.

* src/libvirt.c (virDomainGetVcpusFlags): Allow
VIR_DOMAIN_AFFECT_CURRENT.
* src/libxl/libxl_driver.c (libxlDomainGetVcpusFlags): Likewise.
* src/qemu/qemu_driver.c (qemudDomainGetVcpusFlags): Likewise.
* src/test/test_driver.c (testDomainGetVcpusFlags): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainGetVcpusFlags): Likewise.

For all hypervisors that support save and restore, the new API
now performs the same functions as the old.

VBox is excluded from this list, because its existing domainsave
is broken (there is no corresponding domainrestore, and there
is no control over the filename used in the save).  A later
patch should change vbox to use its implementation for
managedsave, and teach start to use managedsave results.

* src/libxl/libxl_driver.c (libxlDomainSave): Move guts...
(libxlDomainSaveFlags): ...to new function.
(libxlDomainRestore): Move guts...
(libxlDomainRestoreFlags): ...to new function.
* src/test/test_driver.c (testDomainSave, testDomainSaveFlags)
(testDomainRestore, testDomainRestoreFlags): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainSave)
(xenUnifiedDomainSaveFlags, xenUnifiedDomainRestore)
(xenUnifiedDomainRestoreFlags): Likewise.
* src/qemu/qemu_driver.c (qemudDomainSave, qemudDomainRestore):
Rename and move guts.
(qemuDomainSave, qemuDomainSaveFlags, qemuDomainRestore)
(qemuDomainRestoreFlags): ...here.
(qemudDomainSaveFlag): Rename...
(qemuDomainSaveInternal): ...to this, and update callers.

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.

In preparation for a future patch adding new virFile APIs.

* src/util/files.h, src/util/files.c: Move...
* src/util/virfile.h, src/util/virfile.c: ...here, and rename
functions to virFile prefix.  Macro names are intentionally
left alone.
* *.c: All '#include "files.h"' uses changed.
* src/Makefile.am (UTIL_SOURCES): Reflect rename.
* cfg.mk (exclude_file_name_regexp--sc_prohibit_close): Likewise.
* src/libvirt_private.syms: Likewise.
* docs/hacking.html.in: Likewise.
* HACKING: Regenerate.

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.

The drivers were accepting domain configs without checking if those
were actually meant for them. For example the LXC driver happily
accepts configs with type QEMU.

Add a check for the expected domain types to the virDomainDefParse*
functions.

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.

Well, the remaining drivers that already had the get/set
scheduler parameter functionality to begin with.

For now, this blindly treats VIR_DOMAIN_SCHEDINFO_CURRENT as
the only supported operation for these 5 domains; it will
take domain-specific patches if more specific behavior is
preferred.

* src/esx/esx_driver.c (esxDomainGetSchedulerParameters)
(esxDomainSetSchedulerParameters): Move guts...
(esxDomainGetSchedulerParametersFlags)
(esxDomainSetSchedulerParametersFlags): ...to new functions.
* src/libxl/libxl_driver.c (libxlDomainGetSchedulerParameters)
(libxlDomainSetSchedulerParameters)
(libxlDomainGetSchedulerParametersFlags)
(libxlDomainSetSchedulerParametersFlags): Likewise.
* src/lxc/lxc_driver.c (lxcGetSchedulerParameters)
(lxcSetSchedulerParameters, lxcGetSchedulerParametersFlags)
(lxcSetSchedulerParametersFlags): Likewise.
* src/test/test_driver.c (testDomainGetSchedulerParams)
(testDomainSetSchedulerParams, testDomainGetSchedulerParamsFlags)
(testDomainSetSchedulerParamsFlags): Likewise.
* src/xen/xen_driver.c (xenUnifiedDomainGetSchedulerParameters)
(xenUnifiedDomainSetSchedulerParameters)
(xenUnifiedDomainGetSchedulerParametersFlags)
(xenUnifiedDomainSetSchedulerParametersFlags): Likewise.

Rather mechanical in nature.

* src/driver.h: Use newer virTypedParameter API names.
* src/libvirt.c: Likewise.
* daemon/remote.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/libxl/libxl_driver.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
* src/qemu/qemu_driver.c: Likewise.
* src/remote/remote_driver.c: Likewise.
* src/test/test_driver.c: Likewise.
* src/xen/xen_driver.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xen_hypervisor.h: Likewise.
* src/xen/xend_internal.c: Likewise.
* tools/virsh.c: Likewise.

Add many version number annotations to the internal driver
tables, to allow hvsupport.html to display more accurate
information

Change all the driver struct initializers to use the
C99 style, leaving out unused fields. This will make
it possible to add new APIs without changing every
driver. eg change:

    qemudDomainResume, /* domainResume */
    qemudDomainShutdown, /* domainShutdown */
    NULL, /* domainReboot */
    qemudDomainDestroy, /* domainDestroy */

to

    .domainResume = qemudDomainResume,
    .domainShutdown = qemudDomainShutdown,
    .domainDestroy = qemudDomainDestroy,

And get rid of any existing C99 style initializersr which
set NULL, eg change

     .listPools          = vboxStorageListPools,
     .numOfDefinedPools  = NULL,
     .listDefinedPools   = NULL,
     .findPoolSources    = NULL,
     .poolLookupByName   = vboxStoragePoolLookupByName,

to

     .listPools          = vboxStorageListPools,
     .poolLookupByName   = vboxStoragePoolLookupByName,

Fix some driver names:

  s/virDrvCPUCompare/virDrvCompareCPU/
  s/virDrvCPUBaseline/virDrvBaselineCPU/
  s/virDrvQemuDomainMonitorCommand/virDrvDomainQemuMonitorCommand/
  s/virDrvSecretNumOfSecrets/virDrvNumOfSecrets/
  s/virDrvSecretListSecrets/virDrvListSecrets/

And some driver struct field names:

  s/getFreeMemory/nodeGetFreeMemory/

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

This is needed if we want to transfer a temporary file. If the
transfer is done with iohelper, we might run into a race condition,
where we unlink() file before iohelper is executed.

* src/fdstream.c, src/fdstream.h,
  src/util/iohelper.c: Add new option
* src/lxc/lxc_driver.c, src/qemu/qemu_driver.c,
  src/storage/storage_driver.c, src/uml/uml_driver.c,
  src/xen/xen_driver.c: Expand existing function calls

* 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>

This matches the public API and helps to get rid of some special
case code in the remote generator.

Rename driver API functions and XDR protocol structs.

No functional change included outside of the remote generator.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=664059

Reattaching pci device back to host without destroying guest or
detaching device from guest would cause host to crash. This patch adds
a check before doing device reattach. If the device is being assigned
to guest, libvirt refuses to reattach device to host. The patch only
works for Xen, for it just checks xenstore to get pci device
information.
Signed-off-by: NYufang Zhang <yuzhang@redhat.com>

And from all related macros and functions.

The O_NONBLOCK flag doesn't work as desired on plain files
or block devices. Introduce an I/O helper program that does
the blocking I/O operations, communicating over a pipe that
can support O_NONBLOCK

* src/fdstream.c, src/fdstream.h: Add non-blocking I/O
  on plain files/block devices
* src/Makefile.am, src/util/iohelper.c: I/O helper program
* src/qemu/qemu_driver.c, src/lxc/lxc_driver.c,
  src/uml/uml_driver.c, src/xen/xen_driver.c: Update for
  streams API change