The code is splattered with a mix of

  sizeof foo
  sizeof (foo)
  sizeof(foo)

Standardize on sizeof(foo) and add a syntax check rule to
enforce it
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

After cleanup introduced with previous commit, there is a need for
syntax-check rule taking care of return(). Regexp used in 'prohibit'
parameter is taken from the cleanup commit and modified so it fits
'grep -E' format. Semicolon at the end is needed, otherwise the regexp
could match return with cast.

Exception is created for python source files because we don't have any
documentation restricting the use of return that matches this case.

No thanks to 64-bit windows, with 64-bit pid_t, we have to avoid
constructs like 'int pid'.  Our API in libvirt-qemu cannot be
changed without breaking ABI; but then again, libvirt-qemu can
only be used on systems that support UNIX sockets, which rules
out Windows (even if qemu could be compiled there) - so for all
points on the call chain that interact with this API decision,
we require a different variable name to make it clear that we
audited the use for safety.

Adding a syntax-check rule only solves half the battle; anywhere
that uses printf on a pid_t still needs to be converted, but that
will be a separate patch.

* cfg.mk (sc_correct_id_types): New syntax check.
* src/libvirt-qemu.c (virDomainQemuAttach): Document why we didn't
use pid_t for pid, and validate for overflow.
* include/libvirt/libvirt-qemu.h (virDomainQemuAttach): Tweak name
for syntax check.
* src/vmware/vmware_conf.c (vmwareExtractPid): Likewise.
* src/driver.h (virDrvDomainQemuAttach): Likewise.
* tools/virsh.c (cmdQemuAttach): Likewise.
* src/remote/qemu_protocol.x (qemu_domain_attach_args): Likewise.
* src/qemu_protocol-structs (qemu_domain_attach_args): Likewise.
* src/util/cgroup.c (virCgroupPidCode, virCgroupKillInternal):
Likewise.
* src/qemu/qemu_command.c(qemuParseProcFileStrings): Likewise.
(qemuParseCommandLinePid): Use pid_t for pid.
* daemon/libvirtd.c (daemonForkIntoBackground): Likewise.
* src/conf/domain_conf.h (_virDomainObj): Likewise.
* src/probes.d (rpc_socket_new): Likewise.
* src/qemu/qemu_command.h (qemuParseCommandLinePid): Likewise.
* src/qemu/qemu_driver.c (qemudGetProcessInfo, qemuDomainAttach):
Likewise.
* src/qemu/qemu_process.c (qemuProcessAttach): Likewise.
* src/qemu/qemu_process.h (qemuProcessAttach): Likewise.
* src/uml/uml_driver.c (umlGetProcessInfo): Likewise.
* src/util/virnetdev.h (virNetDevSetNamespace): Likewise.
* src/util/virnetdev.c (virNetDevSetNamespace): Likewise.
* tests/testutils.c (virtTestCaptureProgramOutput): Likewise.
* src/conf/storage_conf.h (_virStoragePerms): Use mode_t, uid_t,
and gid_t rather than int.
* src/security/security_dac.c (virSecurityDACSetOwnership): Likewise.
* src/conf/storage_conf.c (virStorageDefParsePerms): Avoid
compiler warning.

Make it easier to detect invalid cross-directory includes, by
adding a syntax check.  The check is designed to be extensible:
the default case lists only the non-driver directories, and
specific directories can list a different set (for example,
util/ can only use itself, network/ can only use itself, util/,
or conf/).

* .gnulib: Update to latest, for syntax check improvment.
* cfg.mk (sc_prohibit_cross_inclusion): New check.
(sc_prohibit_strncmp, sc_libvirt_unmarked_diagnostics): Simplify.

It's been a while, and we're between releases, so now's as good
a time as any to resync.  This also fixes a build-breaker on
cygwin, where cygwin 1.7.11 introduced a header bug in <termios.h>.

* .gnulib: Update to latest.
* bootstrap: Resync.
* cfg.mk (sc_prohibit_strncmp): Copy upstream changes to
sc_prohibit_strcmp.

Function xmlParseURI does not remove square brackets around IPv6
address when parsing. One of the solutions is making wrappers around
functions working with xmlURI*. This assures that uri->server will be
always properly assigned and it doesn't have to be changed when used
on some new place in the code.
For this purpose, functions virParseURI and virSaveURI were
added. These function are wrappers around xmlParseURI and xmlSaveUri
respectively.
Also there is one new syntax check function to prohibit these functions
anywhere else.

File changes:
 - src/util/viruri.h        -- declaration
 - src/util/viruri.c        -- definition
 - src/libvirt_private.syms -- symbol export
 - src/Makefile.am          -- added source and header files
 - cfg.mk                   -- added sc_prohibit_xmlURI
 - all others               -- ID name and include fixes

This patch starts the process of elevating the python binding code
to be on the same level as the rest of libvirt when it comes to
requiring good coding styles.  Statically linking against the
libvirt_util library makes it much easier to write good code,
rather than having to open-code and reinvent things locally.

Done by global search and replace of s/free(/VIR_FREE(/, followed
by hand-inspection of remaining malloc and redundant memset.

* cfg.mk (exclude_file_name_regexp--sc_prohibit_raw_allocation):
Remove python from exemption.
* python/Makefile.am (INCLUDES): Add gnulib and src/util.  Drop
$(top_builddir)/$(subdir), as automake already guarantees that.
(mylibs, myqemulibs): Pull in libvirt_util and gnulib.
(libvirtmod_la_CFLAGS): Catch compiler warnings if configured to
use -Werror.
* python/typewrappers.c (libvirt_charPtrSizeWrap)
(libvirt_charPtrWrap): Convert free to VIR_FREE.
* python/generator.py (print_function_wrapper): Likewise.
* python/libvirt-override.c: Likewise.

The bulk of this patch was done with:

sed -i 's/\(\bfree *(/VIR_FREE(/g' tests/*.c

followed by fixing the few compile errors that resulted.

* cfg.mk (exclude_file_name_regexp--sc_prohibit_raw_allocation):
Remove tests from exemption.
* tests/testutils.h: Add common header.
* tests/commandhelper.c: Fix offenders.
* tests/cputest.c: Likewise.
* tests/domainsnapshotxml2xmltest.c: Likewise.
* tests/interfacexml2xmltest.c: Likewise.
* tests/networkxml2argvtest.c: Likewise.
* tests/networkxml2xmltest.c: Likewise.
* tests/nodedevxml2xmltest.c: Likewise.
* tests/nodeinfotest.c: Likewise.
* tests/nwfilterxml2xmltest.c: Likewise.
* tests/qemuargv2xmltest.c: Likewise.
* tests/qemuxml2argvtest.c: Likewise.
* tests/qemuxml2xmltest.c: Likewise.
* tests/qemuxmlnstest.c: Likewise.
* tests/qparamtest.c: Likewise.
* tests/sexpr2xmltest.c: Likewise.
* tests/storagepoolxml2xmltest.c: Likewise.
* tests/storagevolxml2xmltest.c: Likewise.
* tests/testutils.c: Likewise.
* tests/virshtest.c: Likewise.
* tests/xencapstest.c: Likewise.
* tests/xmconfigtest.c: Likewise.
* tests/xml2sexprtest.c: Likewise.

Our HACKING discourages use of malloc and free, for at least
a couple of years now.  But we weren't enforcing it, until now :)

For now, I've exempted python and tests, and will clean those up
in subsequent patches.  Examples should be permanently exempt,
since anyone copying our examples won't have use of our
internal-only memory.h via libvirt_util.la.

* cfg.mk (sc_prohibit_raw_allocation): New rule.
(exclude_file_name_regexp--sc_prohibit_raw_allocation): and
exemptions.
* src/cpu/cpu.c (cpuDataFree): Avoid false positive.
* src/conf/network_conf.c (virNetworkDNSSrvDefParseXML): Fix
offenders.
* src/libxl/libxl_conf.c (libxlMakeDomBuildInfo, libxlMakeVfb)
(libxlMakeDeviceModelInfo): Likewise.
* src/rpc/virnetmessage.c (virNetMessageSaveError): Likewise.
* tools/virsh.c (_vshMalloc, _vshCalloc): Likewise.

* src/libvirt_public.syms: Death to tabs
* cfg.mk: Check .syms files for tabs

Noticed while reviewing the previous patch; thankfully, there
are no violations.

* cfg.mk (useless_free_options): Add xmlFreeNode.

When converting a linear enum to a string, we have checks in
place in the VIR_ENUM_IMPL macro to ensure that there is one
string for every value, which lets us quickly flag if a user
added a value but forgot to add a counterpart string.  However,
this only works if we use the _LAST marker.

* cfg.mk (sc_require_enum_last_marker): New syntax check.
* src/conf/domain_conf.h (virDomainSnapshotState): Add new marker.
* src/conf/domain_conf.c (virDomainSnapshotState): Fix offender.
* src/qemu/qemu_monitor_json.c (qemuMonitorWatchdogAction)
(qemuMonitorIOErrorAction, qemuMonitorGraphicsAddressFamily):
Likewise.
* src/util/virtypedparam.c (virTypedParameter): Likewise.

* .gnulib: Update to latest, for improved 'make syntax-check' and
compiler warnings.
* m4/virt-compile-warnings.m4 (LIBVIRT_COMPILE_WARNINGS):
Re-silence -Wformat-nonliteral.
* cfg.mk (_test_script_regex): Recognize our test scripts.
* gnulib/local/lib/*.diff: Drop, now that gnulib has this.
* tests/virsh-optparse: Fix use of compare.
* tests/virsh-schedinfo: Likewise.

Commit f7bd00c1 pulled in a gnulib module that fails to compile
on mingw.  While it would be nice to pull in a newer version of
.gnulib that fixes this, it is difficult to backport any .gnulib
update to older releases.  So, it makes sense to take advantage
of gnulib-tool's ability to support local diffs, where we can
apply specific diffs in our use of gnulib without waiting for
upstream gnulib to pick up those changes, as well as avoiding
a wholesale .gnulib update.  The existence of local diffs will
also make it easier to backport fixes against a tarball (as long
as a tarball and libvirt.git share the same .gnulib commit, then
the tarball can be patched by applying the same local diffs as
a post-release libvirt.git commit, without having to rerun an
entire gnulib-tool bootstrap).

This patch introduces the framework for supporting local diffs,
without actually introducing any.

* bootstrap.conf (local_gl_dir): New variable.
* autogen.sh (bootstrap_hash): Hash any local diffs, to force a
re-bootstrap if just diffs change.
* cfg.mk (_update_required): Likewise.

The current I/O code for LXC uses a hand crafted event loop
to forward I/O between the container & host app, based on
epoll to handle EOF on PTYs. This event loop is not easily
extensible to add more consoles, or monitor other types of
file descriptors.

Remove the custom event loop and replace it with a normal
libvirt event loop. When detecting EOF on a PTY, disable
the event watch on that FD, and fork off a background thread
that does a edge-triggered epoll() on the FD. When the FD
finally shows new incoming data, the thread re-enables the
watch on the FD and exits.

When getting EOF from a read() on the PTY, the existing code
would do waitpid(WNOHANG) to see if the container had exited.
Unfortunately there is a race condition, because even though
the process has closed its stdio handles, it might still
exist.

To deal with this the new event loop uses a SIG_CHILD handler
to perform the waitpid only when the container is known to
have actually exited.

* src/lxc/lxc_controller.c: Rewrite the event loop to use
  the standard APIs.

This removes the old example for legacy probes and adds two
new scripts demonstrating many of the new probe point facilities.

The rpc-monitor.stp script will print out friendly details of all
RPC traffic between a libvirt client/server. This is incredibly
useful in seeing what RPC calls are being made, and also debugging
problems in the RPC protocol code

The events.stp script will print out lots of info about the poll
event loop, which is useful for debugging event handling problems

* examples/systemtap/events.stp, examples/systemtap/rpc-monitor.stp:
  New examples
* examples/systemtap/client.stp: Remove obsolete example

The libvirtd daemon had a few crude system tap probes. Some of
these were broken during the RPC rewrite. The new modular RPC
code is structured in a way that allows much more effective
tracing. Instead of trying to hook up the original probes,
define a new set of probes for the RPC and event code.

The master probes file is now src/probes.d.  This contains
probes for virNetServerClientPtr, virNetClientPtr, virSocketPtr
virNetTLSContextPtr and virNetTLSSessionPtr modules. Also add
probes for the poll event loop.

The src/dtrace2systemtap.pl script can convert the probes.d
file into a libvirt_probes.stp file to make use from systemtap
much simpler.

The src/rpc/gensystemtap.pl script can generate a set of
systemtap functions for translating RPC enum values into
printable strings. This works for all RPC header enums (program,
type, status, procedure) and also the authentication enum

The PROBE macro will automatically generate a VIR_DEBUG
statement, so any place with a PROBE can remove any existing
manual DEBUG statements.

* daemon/libvirtd.stp, daemon/probes.d: Remove obsolete probing
* daemon/libvirtd.h: Remove probe macros
* daemon/Makefile.am: Remove all probe buildings/install
* daemon/remote.c: Update authentication probes
* src/dtrace2systemtap.pl, src/rpc/gensystemtap.pl: Scripts
  to generate STP files
* src/internal.h: Add probe macros
* src/probes.d: Master list of probes
* src/rpc/virnetclient.c, src/rpc/virnetserverclient.c,
  src/rpc/virnetsocket.c, src/rpc/virnettlscontext.c,
  src/util/event_poll.c: Insert probe points, removing any
  DEBUG statements that duplicate the info

Bug introduced in commit 675464b1.  On an OOM, this would try to
dereference a char* and free the contents as a pointer, which is
doomed to failure.

Adding a syntax check will prevent mistakes like this in the future.

* cfg.mk (sc_prohibit_internal_functions): New syntax check.
(exclude_file_name_regexp--sc_prohibit_internal_functions): Add
exemptions.
* daemon/remote.c (remoteRelayDomainEventIOError)
(remoteRelayDomainEventIOErrorReason)
(remoteRelayDomainEventGraphics, remoteRelayDomainEventBlockJob):
Use correct free function.

When libvirt calls virInitialize it creates a thread local
for the virErrorPtr storage, and registers a callback to
cleanup memory when a thread exits. When libvirt is dlclose()d
or otherwise made non-resident, the callback function is
removed from memory, but the thread local may still exist
and if a thread later exists, it will invoke the callback
and SEGV. There may also be other thread locals with callbacks
pointing to libvirt code, so it is in general never safe to
unload libvirt.so from memory once initialized.

To allow dlclose() to succeed, but keep libvirt.so resident
in memory, link with '-z nodelete'. This issue was first
found with the libvirt CIM provider, but can potentially
hit many of the dynamic language bindings which all ultimately
involve dlopen() in some way, either on libvirt.so itself,
or on the glue code for the binding which in turns links
to libvirt

* configure.ac, src/Makefile.am: Ensure libvirt.so is linked
  with -z nodelete
* cfg.mk, .gitignore, tests/Makefile.am, tests/shunloadhelper.c,
  tests/shunloadtest.c: A test case to unload libvirt while
  a thread is still running.

Commit 2a0d75e5 added file python/libvirt-qemu-override.c that contains
code that does not pass "make syntax-check". This patch adds an
exception for this file and the check.

prohibit_always_true_header_tests
python/libvirt-qemu-override.c:17:#undef HAVE_PTHREAD_H
maint.mk: do not test the above HAVE_<header>_H symbol(s);
  with the corresponding gnulib module, they are always true
make: *** [sc_prohibit_always_true_header_tests] Error 1

* cfg.mk (useless_free_options): Add xmlFreeDoc, xmlBufferFree.
* src/esx/esx_vi.c (ESX_VI__TEMPLATE__FREE): Fix offenders.
* tools/virsh.c (cmdFreecell, cmdVNCDisplay, cmdTTYConsole)
(cmdDetachInterface, cmdDetachDisk, cmdSnapshotCreate)
(cmdSnapshotCreateAs, cmdSnapshotList, cmdSnapshotParent):
Likewise.

These functions parse given XML node and return pointer to the
output. Unknown elements are silently ignored. Attributes must
be integer and must fit in unsigned long long.

Free function frees elements of virBandwidth structure.

This test case checks certification validation rules for

 - Basic constraints
 - Key purpose
 - Key usage
 - Start/expiry times

It checks initial context creation sanity checks, and live
session validation

O_DIRECT has stringent requirements.  Rather than make lots of changes
at each site that wants to use O_DIRECT, it is easier to offload
the work through a helper process that mirrors the I/O between a
pipe and the actual direct fd, so that the other end of the pipe
no longer has to worry about constraints.

Plus, if the kernel ever gains better posix_fadvise support, then we
only have to touch a single file to let all callers benefit from a
more efficient way to avoid file system caching.

* src/util/virfile.h (virFileDirectFdFlag, virFileDirectFdNew)
(virFileDirectFdClose, virFileDirectFdFree): New prototypes.
* src/util/virdirect.c: Implement new wrapper object.
* src/libvirt_private.syms (virfile.h): Export new symbols.
* cfg.mk (useless_free_options): Add to list.
* po/POTFILES.in: Add new translations.

the domain XML <interface> element is updated in the following ways:

1) <virtualportprofile> can be specified when source type='network'
(previously it was only valid for source type='direct')

2) A new attribute "portgroup" has been added to the <source>
element. When source type='network' (the only time portgroup is
recognized), extra configuration information will be taken from the
<portgroup> element of the given name in the network definition.

3) Each virDomainNetDef now also potentially has a
virDomainActualNetDef which is a private object (never
exported/imported via the public API, and not defined in the RNG) that
is used to maintain information about the physical device that was
actually used for a NetDef of type VIR_DOMAIN_NET_TYPE_NETWORK.

The virDomainActualNetDef will only be parsed/formatted if the
parse/format function is called with the
VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET flag set (which is only needed when
saving/loading a running domain's state info to the stateDir).

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.

* cfg.mk (sc_copyright_format): Add to rule.
* src/util/files.h: Fix offenders.
* src/util/files.c: Likewise.

Enforce the recent flags cleanups - we want to use 'unsigned int flags'
in any of our APIs (except where backwards compatibility is important,
in the public migration APIs), and that all flags are checked for
validity (except when there are stub functions that completely
ignore the flags argument).

There are a few minor tweaks done here to avoid false positives:
signed arguments passed to open() are renamed oflags, and flags
arguments that are legitimately ignored are renamed flags_unused.

* cfg.mk (sc_flags_usage): New rule.
(exclude_file_name_regexp--sc_flags_usage): And a few exemptions.
(sc_flags_debug): Tweak wording.
* src/util/iohelper.c (runIO, main): Rename variable.
* src/util/util.c (virSetInherit): Likewise.
* src/fdstream.h (virFDStreamOpenFile, virFDStreamCreateFile):
Likewise.
* src/fdstream.c (virFDStreamOpenFileInternal)
(virFDStreamOpenFile, virFDStreamCreateFile): Likewise.
* src/util/command.c (virExecWithHook) [WIN32]: Likewise.
* src/util/util.c (virFileOpenAs, virDirCreate) [WIN32]: Likewise.
* src/locking/lock_manager.c (virLockManagerPluginNew)
[!HAVE_DLFCN_H]: Likewise.
* src/locking/lock_driver_nop.c (virLockManagerNopNew)
(virLockManagerNopAddResource, virLockManagerNopAcquire)
(virLockManagerNopRelease, virLockManagerNopInquire): Likewise.

Getting metadata on storage allocates a memory (path) which need to
be freed after use otherwise it gets leaked. This means after use of
virStorageFileGetMetadataFromFD or virStorageFileGetMetadata one
must call virStorageFileFreeMetadata to free it. This function frees
structure internals and structure itself.

The compiler might optimize based on our declaration that something
is unused.  Putting that declaration in the header risks getting
out of sync with the actual implementation, so it belongs better
only in the .c files.  We were mostly compliant, and a new syntax
check will help us in the future.

* cfg.mk (sc_avoid_attribute_unused_in_header): New syntax check.
* src/nodeinfo.h (nodeGetCPUStats, nodeGetMemoryStats): Delete
attribute already present in .c file.
* src/qemu/qemu_domain.h (qemuDomainEventFlush): Likewise.
* src/util/virterror_internal.h (virReportErrorHelper): Parameters
are actually used by .c file.
* src/xenxs/xen_sxpr.h (xenFormatSxprDisk): Adjust prototype.
* src/xenxs/xen_sxpr.c (xenFormatSxprDisk): Delete unused argument.
(xenFormatSxpr): Adjust caller.
* src/xen/xend_internal.c (xenDaemonAttachDeviceFlags)
(xenDaemonUpdateDeviceFlags): Likewise.
Suggested by Daniel Veillard.

Continuation of commit 313ac7fd, and enforce things with a syntax
check.

Technically, virNetServerClientCalculateHandleMode is not printing
a mode_t, but rather a collection of VIR_EVENT_HANDLE_* bits;
however, these bits are < 8, so there is no different in the
output, and that was the easiest way to silence the new syntax check.

* cfg.mk (sc_flags_debug): New syntax check.
(exclude_file_name_regexp--sc_flags_debug): Add exemptions.
* src/fdstream.c (virFDStreamOpenFileInternal): Print flags in
hex, mode_t in octal.
* src/libvirt-qemu.c (virDomainQemuMonitorCommand)
(virDomainQemuAttach): Likewise.
* src/locking/lock_driver_nop.c (virLockManagerNopInit): Likewise.
* src/locking/lock_driver_sanlock.c (virLockManagerSanlockInit):
Likewise.
* src/locking/lock_manager.c: Likewise.
* src/qemu/qemu_migration.c: Likewise.
* src/qemu/qemu_monitor.c: Likewise.
* src/rpc/virnetserverclient.c
(virNetServerClientCalculateHandleMode): Print mode with %o.

* cfg.mk (VC_LIST_ALWAYS_EXCLUDE_REGEX): Exempt
docs/api_extension/*.patch.
(exclude_file_name_regexp--sc_prohibit_always_true_header_tests)
(exclude_file_name_regexp--sc_prohibit_empty_lines_at_EOF)
(exclude_file_name_regexp--sc_prohibit_fork_wrappers)
(exclude_file_name_regexp--sc_trailing_blank): Simplify.
(exclude_file_name_regexp--sc_prohibit_gettext_noop): Delete.
(exclude_file_name_regexp--sc_prohibit_close)
(exclude_file_name_regexp--sc_prohibit_nonreentrant)
(exclude_file_name_regexp--sc_prohibit_sprintf): Tighten.

Incrementally running 'make syntax-check' on a tree previously
built after commit 62dee6fa but before 44036460 fails sc_po_check
(because the generated qemu_dispatch.h gained translatable strings).
This is a followup to commit addaa537 for that scenario.

* cfg.mk (sc_po_check): Add another prereq.
($(srcdir)/daemon/qemu_dispatch.h): Add rule.

For good or for bad, I did a fresh checkout, ./autogen.sh, then
'configure', then 'make syntax-check', and was surprised that it
failed.  Running 'make' before 'make syntax-check' cleaned up the
issue, but this patch makes it work up front.

* cfg.mk (sc_po_check): Add prerequisites.

The last patch was incomplete.  The translated strings merely
moved between generated file names, rather than disappearing.

* cfg.mk (generated_files): Update generated file names.
* po/POTFILES.in: Add remote_dispatch.h

Move the daemon/remote_generator.pl to src/rpc/gendispatch.pl
and move the src/remote/rpcgen_fix.pl to src/rpc/genprotocol.pl

* daemon/Makefile.am: Update for new name/location of generator
* src/Makefile.am: Update for new name/location of generator

To facilitate creation of new clients using XDR RPC services,
pull alot of the remote driver code into a set of reusable
objects.

 - virNetClient: Encapsulates a socket connection to a
   remote RPC server. Handles all the network I/O for
   reading/writing RPC messages. Delegates RPC encoding
   and decoding to the registered programs

 - virNetClientProgram: Handles processing and dispatch
   of RPC messages for a single RPC (program,version).
   A program can register to receive async events
   from a client

 - virNetClientStream: Handles generic I/O stream
   integration to RPC layer

Each new client program now merely needs to define the list of
RPC procedures & events it wants and their handlers. It does
not need to deal with any of the network I/O functionality at
all.

Allow RPC servers to advertise themselves using MDNS,
via Avahi

* src/rpc/virnetserver.c, src/rpc/virnetserver.h: Allow
  registration of MDNS services via avahi
* src/rpc/virnetserverservice.c, src/rpc/virnetserverservice.h: Add
  API to fetch the listen port number
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Add API to
  fetch the local port number
* src/rpc/virnetservermdns.c, src/rpc/virnetservermdns.h: Represent
  an MDNS advertisement

To facilitate creation of new daemons providing XDR RPC services,
pull a lot of the libvirtd daemon code into a set of reusable
objects.

 * virNetServer: A server contains one or more services which
   accept incoming clients. It maintains the list of active
   clients. It has a list of RPC programs which can be used
   by clients. When clients produce a complete RPC message,
   the server passes this onto the corresponding program for
   handling, and queues any response back with the client.

 * virNetServerClient: Encapsulates a single client connection.
   All I/O for the client is handled, reading & writing RPC
   messages.

 * virNetServerProgram: Handles processing and dispatch of
   RPC method calls for a single RPC (program,version).
   Multiple programs can be registered with the server.

 * virNetServerService: Encapsulates socket(s) listening for
   new connections. Each service listens on a single host/port,
   but may have multiple sockets if on a dual IPv4/6 host.

Each new daemon now merely has to define the list of RPC procedures
& their handlers. It does not need to deal with any network related
functionality at all.