Merge the doNonTunnelMigrate2 and doTunnelMigrate2 methods
into one doPeer2PeerMigrate2 method, since they are substantially
the same. With the introduction of v3 migration, this will be
even more important, to avoid massive code duplication.

* src/qemu/qemu_migration.c: Merge tunnel & non-tunnel migration

To facilitate the introduction of the v3 migration protocol,
the doTunnelMigrate method is refactored into two pieces. One
piece is intended to mirror the flow of virDomainMigrateVersion2,
while the other is the helper for setting up sockets and processing
the data.

Previously socket setup would be done before the 'prepare' step,
so errors could be dealt with immediately, avoiding need to shut
off the destination QEMU. In the new split, socket setup is done
after the 'prepare' step. This is not a serious problem, since
the control flow already requires calling 'finish' to tear down
the destination QEMU upon several errors.

* src/qemu/qemu_migration.c:

Use the graphics information from the QEMU migration cookie to
issue a 'client_migrate_info' monitor command to QEMU. This causes
the SPICE client to automatically reconnect to the target host
when migration completes

* src/qemu/qemu_migration.c: Set data for SPICE client relocation
  before starting migration on src
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c, src/qemu/qemu_monitor_json.h,
  src/qemu/qemu_monitor_text.c, src/qemu/qemu_monitor_text.h: Add
  new qemuMonitorGraphicsRelocate() command

Extend the QEMU migration cookie structure to allow information
about the destination host graphics setup to be passed by to
the source host. This will enable seamless migration of any
connected graphics clients

* src/qemu/qemu_migration.c: Add graphics info to migration
  cookies
* daemon/libvirtd.c: Always initialize gnutls to enable
  x509 cert parsing in QEMU

The migration protocol has support for a 'cookie' parameter which
is an opaque array of bytes as far as libvirt is concerned. Drivers
may use this for passing around arbitrary extra data they might
need during migration. The QEMU driver needs to do a few things:

 - Pass hostname/uuid to allow strict protection against localhost
   migration attempts
 - Pass SPICE/VNC server port from the target back to the source to
   allow seamless relocation of client sessions
 - Pass lock driver state from source to destination

This patch introduces the basic glue for handling cookies
but only includes the host/guest UUID & name.

* src/libvirt_private.syms: Export virXMLParseStrHelper
* src/qemu/qemu_migration.c, src/qemu/qemu_migration.h: Parsing
  and formatting of migration cookies
* src/qemu/qemu_driver.c: Pass in cookie parameters where possible
* src/remote/remote_protocol.h, src/remote/remote_protocol.x: Change
  cookie max length to 16384 bytes

The qemuMigrationPrepareTunnel method should not unlock the
qemu driver, since that is the caller's job.

* src/qemu/qemu_migration.c: Fix qemuMigrationPrepareTunnel
  unlocking of QEMU driver

Only in drivers which use virDomainObj, drivers that query hypervisor
for domain status need to be updated separately in case their hypervisor
supports this functionality.

The reason is also saved into domain state XML so if a domain is not
running (i.e., no state XML exists) the reason will be lost by libvirtd
restart. I think this is an acceptable limitation.

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>

* src/qemu/qemu_migration.c, src/qemu/qemu_migration.h: Remove
  qemuCaps parameters & use cached data
* src/qemu/qemu_driver.c: Don't create & pass qemuCaps to
  migration methods

Detected by clang.

* src/qemu/qemu_migration.c (qemuMigrationToFile): Nothing later
uses is_reg.

The two ends of the pipe used for feeding QEMU tunnelled
migration data were interchanged, so QEMU got given the
"write" end instead of the "read" end.

The qemuMigrationPrepareTunnel method was also immediately
closing the "write" end of the pipe, so the stream failed
to actually write anything.

* src/qemu/qemu_migration.c: Swap tunnelled migration
  pipe FDs & don't close pipe given to stream

If the migrateFrom is "stdio" not "stdin", qemuBuildCommandLine()
will convert it to exec:cat or fd:n.

My earlier testing for commit 34fa0de0 was done while starting
just-built libvirt from an unconfined_t shell, where the fds happened
to work when transferring to qemu.  But when installed and run under
virtd_t, failure to label the raw file (with no compression) or the
pipe (with compression) triggers SELinux failures when passing fds
over SCM_RIGHTS to svirt_t qemu.

* src/qemu/qemu_migration.c (qemuMigrationToFile): When passing
FDs, make sure they are labeled.

Spawn the compressor ourselves, instead of requiring the shell.

* src/qemu/qemu_migration.c (qemuMigrationToFile): Spawn
compression helper process when needed.

SELinux labeling and cgroup ACLs aren't required if we hand a
pre-opened fd to qemu.  All the more reason to love fd: migration.

* src/qemu/qemu_migration.c (qemuMigrationToFile): Skip steps
that are irrelevant in fd migration.

This points out that core dumps (still) don't work for root-squash
NFS, since the fd is not opened correctly.  This patch should not
introduce any functionality change, it is just a refactoring to
avoid duplicated code.

* src/qemu/qemu_migration.h (qemuMigrationToFile): New prototype.
* src/qemu/qemu_migration.c (qemuMigrationToFile): New function.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag, doCoreDump): Use
it.

Enhance the QEMU migration monitoring loop, so that it can get
a signal to change migration speed on the fly

* src/qemu/qemu_domain.h: Add signal for changing speed on the fly
* src/qemu/qemu_driver.c: Wire up virDomainMigrateSetSpeed driver
* src/qemu/qemu_migration.c: Support signal for changing speed

Outgoing migration still uses a Unix socket and or exec netcat until
the next patch.

* src/qemu/qemu_migration.c (qemuMigrationPrepareTunnel):
Replace Unix socket with simpler pipe.
Suggested by Paolo Bonzini.

Also add ATTRIBUTE_NONNULL markers.

* src/qemu/qemu_audit.h: The pattern qemuDomainXXXAudit is
inconsistent; prefer qemuAuditXXX instead.
* src/qemu/qemu_audit.c: Reflect the renames.
* src/qemu/qemu_driver.c: Likewise.
* src/qemu/qemu_hotplug.c: Likewise.
* src/qemu/qemu_migration.c: Likewise.
* src/qemu/qemu_process.c: Likewise.

This is done for two reasons:
- we are getting very close to 64 flags which is the maximum we can use
  with unsigned long long
- by using LL constants in enum we already violates C99 constraint that
  enum values have to fit into int

The new name complies more with the fact that it contains a set of
qemuCapsFlags.

Three new functions (qemuCapsSet, qemuCapsClear, and qemuCapsGet) were
introduced replacing direct bit operations.

The new names comply more with the fact that they are all members of
enum qemuCapsFlags.

The introduction of the v3 migration protocol, along with
support for migration cookies, will significantly expand
the size of the migration code. Move it all to a separate
file to make it more manageable

The functions are not moved 100%. The API entry points
remain in the main QEMU driver, but once the public
virDomainPtr is resolved to the internal virDomainObjPtr,
all following code is moved.

This will allow the new v3 API entry points to call into the
same shared internal migration functions

* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
  qemuDomainFormatXML helper method
* src/qemu/qemu_driver.c: Remove all migration code
* src/qemu/qemu_migration.c, src/qemu/qemu_migration.h: Add
  all migration code.