A character device's target (it's interface in the guest) had only a
single property: port. This patch is in preparation for adding targets
which require other properties.
Since this changes the conf type for character devices this affects
a number of drivers:

* src/conf/domain_conf.[ch] src/esx/esx_vmx.c src/qemu/qemu_conf.c
  src/qemu/qemu_driver.c src/uml/uml_conf.c src/uml/uml_driver.c
  src/vbox/vbox_tmpl.c src/xen/xend_internal.c src/xen/xm_internal.c:
  target properties are moved into a union in virDomainChrDef, and a
  targetType field is added to identify which union member should be
  used. All current code which touches a virDomainChrDef is updated both
  to use the new union field, and to populate targetType if necessary.

- Don't duplicate SystemError
- Use proper error code in domain_conf
- Fix a broken error call in qemu_conf
- Don't use VIR_ERR_ERROR in security driver (isn't a valid code in this case)

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.

The LXC driver was mistakenly returning -1 for lxcStartup()
in scenarios that are not an error. This caused the libvirtd
to quit for unprivileged users. This fixes the return code
of LXC driver, and also adds a "name" field to the virStateDriver
struct and logging to make it easier to find these problems
in the future

* src/driver.h: Add a 'name' field to state driver to allow
  easy identification during failures
* src/libvirt.c: Log name of failed driver for virStateInit
  failures
* src/lxc/lxc_driver.c: Don't return a failure code for
  lxcStartup() if LXC is not available on this host, simply
  disable the driver.
* src/network/bridge_driver.c, src/node_device/node_device_devkit.c,
  src/node_device/node_device_hal.c, src/opennebula/one_driver.c,
  src/qemu/qemu_driver.c, src/remote/remote_driver.c,
  src/secret/secret_driver.c, src/storage/storage_driver.c,
  src/uml/uml_driver.c, src/xen/xen_driver.c: Fill in name
  field in virStateDriver struct

Nearly all of the methods in src/util/util.h have error codes that
must be checked by the caller to correct detect & report failure.
Add ATTRIBUTE_RETURN_CHECK to ensure compile time validation of
this

* daemon/libvirtd.c: Add explicit check on return value of virAsprintf
* src/conf/domain_conf.c: Add missing check on virParseMacAddr return
  value status & report error
* src/network/bridge_driver.c: Add missing OOM check on virAsprintf
  and report error
* src/qemu/qemu_conf.c: Add missing check on virParseMacAddr return
  value status & report error
* src/security/security_selinux.c: Remove call to virRandomInitialize
  that's done in libvirt.c already
* src/storage/storage_backend_logical.c: Add check & log on virRun
  return status
* src/util/util.c: Add missing checks on virAsprintf/Run status
* src/util/util.h: Annotate all methods with ATTRIBUTE_RETURN_CHECK
  if they return an error status code
* src/vbox/vbox_tmpl.c: Add missing check on virParseMacAddr
* src/xen/xm_internal.c: Add missing checks on virAsprintf
* tests/qemuargv2xmltest.c: Remove bogus call to virRandomInitialize()

In xenInotifyXendDomainsDirLookup() the wrong UUID variable is used
to search in the config info list.

In xenInotifyEvent() the event is dispatched if it's NULL.

Both were introduced in bc898df2.

xenUnifiedDomainEventRegister() calls out to
virDomainEventCallbackListAdd(), which increments the reference
count on the connection.  That is fine, but then
xenUnifiedDomainEventRegister() increments the usage count again,
leading to a usage count leak.  Remove the increment in the xen
register, and the UnrefConnect in the xen unregister.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Most of the hash iterators need to modify either payload of
data args. The const annotation prevents this.

* src/util/hash.h, src/util/hash.c: Remove const-ness from
  virHashForEach/Iterator
* src/xen/xm_internal.c: Remove bogus casts

If one has e.g.

  <guest>
    <os_type>hvm</os_type>
    <arch name='x86_64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-x86_64</emulator>
      <machine>pc-0.11</machine>
      <machine canonical='pc-0.11'>pc</machine>
      <machine>pc-0.10</machine>
      <machine>isapc</machine>
      <domain type='qemu'>
      </domain>
      <domain type='kvm'>
        <emulator>/usr/bin/kvm</emulator>
        <machine>pc</machine>
        <machine>isapc</machine>
      </domain>
    </arch>
  </guest>

and start a guest with:

  <domain type='kvm'>
    ...
    <os>
      <type arch='x86_64'>hvm</type>
      ...
    </os>
  </domain>

then the default machine type should be 'pc' and not 'pc-0.11'

Issue was reported by Anton Protopopov.

* src/capabilities.[ch]: pass the domain type to
  virCapabilitiesDefaultGuestArch() and use it to look up the default
  machine type from a specific guest domain if needed.

* src/conf/domain_conf.c, src/xen/xm_internal.c: update

* tests/qemuxml2argvdata/qemuxml2argv-machine-aliases2.xml: update
  the domain type to 'kvm' and remove the machine type to check
  that the default gets looked up correctly

Introduces several new public API options for migration

 - VIR_MIGRATE_PEER2PEER: With this flag the client only
   invokes the virDomainMigratePerform method, expecting
   the source host driver to do whatever is required to
   complete the entire migration process.
 - VIR_MIGRATE_TUNNELLED: With this flag the actual data
   for migration will be tunnelled over the libvirtd RPC
   channel. This requires that VIR_MIGRATE_PEER2PEER is
   also set.
 - virDomainMigrateToURI: This is variant of the existing
   virDomainMigrate method which does not require any
   virConnectPtr for the destination host. Given suitable
   driver support, this allows for all the same modes as
   virDomainMigrate()

The URI for VIR_MIGRATE_PEER2PEER must be a valid libvirt
URI. For non-p2p migration a hypervisor specific migration
URI is used.

virDomainMigrateToURI without a PEER2PEER flag is only
support for Xen currently, and it involves XenD talking
directly to XenD, no libvirtd involved at all.

* include/libvirt/libvirt.h.in: Add VIR_MIGRATE_PEER2PEER
  flag for migration
* src/libvirt_internal.h: Add feature flags for peer to
  peer migration (VIR_FEATURE_MIGRATE_P2P) and direct
  migration (VIR_MIGRATE_PEER2PEER mode)
* src/libvirt.c: Implement support for VIR_MIGRATE_PEER2PEER
  and virDomainMigrateToURI APIs.
* src/xen/xen_driver.c: Advertise support for DIRECT migration
* src/xen/xend_internal.c: Add TODO item for p2p migration
* src/libvirt_public.syms: Export virDomainMigrateToURI
  method
* src/qemu/qemu_driver.c: Add support for PEER2PEER and
  migration, and adapt TUNNELLED migration.
* tools/virsh.c: Add --p2p and --direct args and use the
  new virDomainMigrateToURI method where possible.

Implementation of tunnelled migration, using a Unix Domain Socket
on the qemu backend.  Note that this requires very new versions of
qemu (0.10.7 at least) in order to get the appropriate bugfixes.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Add the virStrncpy function, which takes a dst string, source string,
the number of bytes to copy and the number of bytes available in the
dest string.  If the source string is too large to fit into the
destination string, including the \0 byte, then no data is copied and
the function returns NULL.  Otherwise, this function copies n bytes
from source into dst, including the \0, and returns a pointer to the
dst string.  This function is intended to replace all unsafe uses
of strncpy in the code base, since strncpy does *not* guarantee that
the buffer terminates with a \0.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

The commit cb51aa48 "Fix up connection
reference counting." changed the driver closing and virConnectPtr
unref-logic in virConnectClose().

Before this commit virConnectClose() closed all drivers of the given
virConnectPtr and virUnrefConnect()'ed it afterwards. After this
commit the driver-closing is done in virUnrefConnect() if and only if
the ref-count of the virConnectPtr dropped to zero.

This change in execution order leads to a virConnectPtr leak, at least
for connections to Xen.

The relevant call sequences:

virConnectOpen() -> xenUnifiedOpen() ...

... xenInotifyOpen() -> virConnectRef(conn)

... xenStoreOpen() -> xenStoreAddWatch() -> conn->refs++

virConnectClose() -> xenUnifiedClose() ...

... xenInotifyClose() -> virUnrefConnect(conn)

... xenStoreClose() -> xenStoreRemoveWatch() -> virUnrefConnect(conn)

Before the commit this additional virConnectRef/virUnrefConnect calls
where no problem, because virConnectClose() closed the drivers
explicitly and the additional refs added by the Xen subdrivers were
removed properly. After the commit this additional refs result in a
virConnectPtr leak (including a leak of the hypercall file handle;
that's how I noticed this problem), because now the drivers are only
close if and only if the ref-count drops to zero, but this cannot
happen anymore, because the additional refs from the Xen subdrivers
would only be removed if the drivers get closed, but that doesn't
happen because the ref-count cannot drop to zero.

The fix for this problem is simple: remove the
virConnectRef/virUnrefConnect calls from the Xen subdrivers (see
attached patch). Maybe someone could explain why the Xen Inotify and
Xen Store driver do this extra ref-counting, but none of the other Xen
subdrivers. It seems unnecessary to me and can be removed without
problems.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Signed-off-by: NChris Lalancette <clalance@redhat.com>

* src/bridge.c, src/bridge.h, src/buf.c, src/buf.h, src/cgroup.c,
  src/cgroup.h, src/conf.c, src/conf.h, src/event.c, src/event.h,
  src/hash.c, src/hash.h, src/hostusb.c, src/hostusb.h,
  src/iptables.c, src/iptables.h, src/logging.c, src/logging.h,
  src/memory.c, src/memory.h, src/pci.c, src/pci.h, src/qparams.c,
  src/qparams.h, src/stats_linux.c, src/stats_linux.h,
  src/threads-pthread.c, src/threads-pthread.h, src/threads-win32.c,
  src/threads-win32.h, src/threads.c, src/threads.h, src/util.c,
  src/util.h, src/uuid.c, src/uuid.h, src/virterror.c,
  src/virterror_internal.h, src/xml.c, src/xml.h: Move all files
  into src/util/
* daemon/Makefile.am: Add -Isrc/util/ to build flags
* src/Makefile.am: Add -Isrc/util/ to build flags and update for
  moved files
* src/libvirt_private.syms: Export cgroup APIs since they're now
  in util rather than linking directly to drivers
* src/xen/xs_internal.c: Disable bogus virEventRemoveHandle call
  when built under PROXY
* proxy/Makefile.am: Update for changed file locations. Remove
  bogus build of event.c
* tools/Makefile.am, tests/Makefile.am: Add -Isrc/util/ to build flags

* src/Makefile.am, src/proxy_internal.c, src/proxy_internal.h
  src/sexpr.c, src/sexpr.h, src/xen_unified.c, src/xen_unified.h,
  src/xen_internal.c, src/xen_internal.h, src/xen_inotify.c,
  src/xen_inotify.h, src/xend_internal.c, src/xend_internal.h,
  src/xm_internal.c, src/xm_internal.h, src/xs_internal.c,
  src/xs_internal.h: Move to src/xen/ directory
* proxy/Makefile.am, proxy/libvirt_proxy.c, src/Makefile.am,
  src/libvirt.c, tests/sexpr2xmltest.c, tests/statstest.c,
  tests/xencapstest.c, tests/xmconfigtest.c, tests/xml2sexprtest.c:
  Adapt to changed xen location
* src/stats_linux.h, src/stats_linux.c: Remove xen specific block
  stats APIs
* src/qemu_driver.c, src/uml_driver.c: Add missing sys/un.h include
  uncovered after change to stats_linux.h
* src/xen/block_stats.h, src/xen/block_stats.c: Add xen specific
  block stats APIs