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

Systemtap 1.2 <sys/sdt.h> tried to expand STAP_PROBE3 into an
initialization:
  volatile __typeof__(arg) foo = arg;
but that fails if arg was declared as 'char arg[100]'.
Rather than make all callers to PROBE deal with the stupidity
of <sys/sdt.h>, we instead make PROBE cast away the problem.
Some of this preprocessor abuse copies ideas in src/libvirt.c.

* daemon/libvirtd.h (PROBE): Add casts to all arguments, using...
(VIR_ADD_CASTS, VIR_ADD_CAST, VIR_ADD_CAST2, VIR_ADD_CAST3)
(VIR_ADD_CAST_EXPAND, VIR_ADD_CAST_PASTE, VIR_COUNT_ARGS)
(VIR_ARG5, PROBE_EXPAND): New macros.
Reported by Wen Congyang.

This patch adds #if HAVE_SASL where needed in libvirtd.h

This guts the libvirtd daemon, removing all its networking and
RPC handling code. Instead it calls out to the new virServerPtr
APIs for all its RPC & networking work

As a fallout all libvirtd daemon error reporting now takes place
via the normal internal error reporting APIs. There is no need
to call separate error reporting APIs in RPC code, nor should
code use VIR_WARN/VIR_ERROR for reporting fatal problems anymore.

* daemon/qemu_dispatch_*.h, daemon/remote_dispatch_*.h: Remove
  old generated dispatcher code
* daemon/qemu_dispatch.h, daemon/remote_dispatch.h: New dispatch
  code
* daemon/dispatch.c, daemon/dispatch.h: Remove obsoleted code
* daemon/remote.c, daemon/remote.h: Rewrite for new dispatch
  APIs
* daemon/libvirtd.c, daemon/libvirtd.h: Remove all networking
  code
* daemon/stream.c, daemon/stream.h: Update for new APIs
* daemon/Makefile.am: Link to libvirt-net-rpc-server.la

<sys/syslimits.h> is not standardized, so portable programs should
not need to rely on it.  If there really is something that we need
where <sys/syslimits.h> provided the limit but <limits.h> did not,
then that would be a candidate for fixing in gnulib.  But this patch
did not turn up any compilation failures on Linux.

* src/internal.h (includes): Drop unused header.
* daemon/libvirtd.h (includes): Likewise.
* configure.ac (AC_CHECK_HEADERS): Likewise.
Based on a report by Matthias Bolte.

Move the buffers to the heap allocated client/private data structs.

Done mechanically with:
$ git grep -l '\bDEBUG0\? *(' | xargs -L1 sed -i 's/\bDEBUG0\? *(/VIR_&/'

followed by manual deletion of qemudDebug in daemon/libvirtd.c, along
with a single 'make syntax-check' fallout in the same file, and the
actual deletion in src/util/logging.h.

* src/util/logging.h (DEBUG, DEBUG0): Delete.
* daemon/libvirtd.h (qemudDebug): Likewise.
* global: Change remaining clients over to VIR_DEBUG counterpart.

* daemon/libvirtd.h (qemud_server): Change types of members
tracking array sizes, and add allocation trackers.
* daemon/event.c (virEventLoop): Likewise.
(virEventAddHandleImpl, virEventAddTimeoutImpl)
(virEventCleanupTimeouts, virEventCleanupHandles): Use
VIR_RESIZE_N instead of VIR_REALLOC_N.  Tweak debug messages to
match type changes.
* daemon/libvirtd.c (qemudDispatchServer, qemudRunLoop): Likewise.

It is useful to know where the client is connecting from,
so include the socket address in probe data.

* daemon/libvirtd.h: Use virSocketAddr for storing client
  address and keep printable address handy for logging
* daemon/libvirtd.c: Include socket address in client
  connect/disconnect probes
* daemon/probes.d: Add socket address to probes
* examples/systemtap/client.stp: Print socket address
* src/util/network.h: Add sockaddr_un to virSocketAddr union

Adds initial support for dtrace static probes in libvirtd
daemon, assuming use of systemtap dtrace compat shim on
Linux. The probes are inserted for network client connect,
disconnect, TLS handshake states and authentication protocol
states.

This can be tested by running the xample program and then
attempting to connect with any libvirt client (virsh,
virt-manager, etc).

 # stap examples/systemtap/client.stp
  Client fd=44 connected readonly=0
  Client fd=44 auth polkit deny pid:24997,uid:500
  Client fd=44 disconnected
  Client fd=46 connected readonly=1
  Client fd=46 auth sasl allow test
  Client fd=46 disconnected

The libvirtd.stp file should also really not be required,
since it is duplicated info that is already available in
the main probes.d definition file. A script to autogenerate
the .stp file is needed, either in libvirtd tree, or better
as part of systemtap itself.

* Makefile.am: Add examples/systemtap subdir
* autobuild.sh: Disable dtrace for mingw32
* configure.ac: Add check for dtrace
* daemon/.gitignore: Ignore generated dtrace probe file
* daemon/Makefile.am: Build dtrace probe header & object
  files
* daemon/libvirtd.stp: SystemTAP convenience probeset
* daemon/libvirtd.c: Add connect/disconnect & TLS probes
* daemon/remote.c: Add SASL and PolicyKit auth probes
* daemon/probes.d: Master probe definition
* daemon/libvirtd.h: Add convenience macro for probes
  so that compilation is a no-op when dtrace is not available
* examples/systemtap/Makefile.am, examples/systemtap/client.stp
  Example systemtap script using dtrace probe markers
* libvirt.spec.in: Enable dtrace on F13/RHEL6
* mingw32-libvirt.spec.in: Force disable dtrace

Since we are adding a new "per-hypervisor" protocol, we
make it so that the qemu remote protocol uses a new
PROTOCOL and PROGRAM number.  This allows us to easily
distinguish it from the normal REMOTE protocol.

This necessitates changing the proc in remote_message_header
from a "remote_procedure" to an "unsigned", which should
be the same size (and thus preserve the on-wire protocol).

Changes since v1:
 - Fixed up a couple of script problems in remote_generate_stubs.pl
 - Switch an int flag to a bool in dispatch.c

Changes since v2:
 - None

Changes since v3:
 - Change unsigned proc to signed proc, to conform to spec
Signed-off-by: NChris Lalancette <clalance@redhat.com>

When libvirtd exits it is leaving UNIX domain sockets on
the filesystem. These need to be removed.

The qemudInitPaths() method has signficant code churn to
switch from using a pre-allocated buffer on the stack, to
dynamically allocating on the heap.

* daemon/libvirtd.c, daemon/libvirtd.h: Store a reference
  to the UNIX domain socket path and unlink it on shutdown

This wires up the remote driver to handle the new events APIs.
The public API allows an application to request a callback filters
events to a specific domain object, and register multiple callbacks
for the same event type. On the wire there are two strategies for
this

 - Register multiple callbacks with the remote daemon, each
   with filtering as needed
 - Register only one callback per event type, with no filtering

Both approaches have potential inefficiency. In the first scheme,
the same event gets sent over the wire many times if multiple
callbacks are registered. With the second scheme, unneccessary
events get sent over the wire if a per-domain filter is set on
the client. The second scheme is far easier to implement though,
so this patch takes that approach.

* daemon/dispatch.h: Don't export remoteRelayDomainEvent since it
  is no longer needed for unregistering callbacks, instead the
  unique callback ID is used
* daemon/libvirtd.c, daemon/libvirtd.h: Track and unregister
  callbacks based on callback ID, instead of function pointer
* daemon/remote.c: Switch over to using virConnectDomainEventRegisterAny
  instead of legacy virConnectDomainEventRegister function. Refactor
  remoteDispatchDomainEventSend() to cope with arbitrary event types
* src/driver.h, src/driver.c: Move verify() call into source file
  instead of header, to avoid polluting the global namespace with
  the verify function name
* src/remote/remote_driver.c: Implement new APIs for event
  registration. Refactor processCallDispatchMessage() to cope
  with arbitrary incoming event types. Merge remoteDomainQueueEvent()
  into processCallDispatchMessage() to avoid duplication of code.
  Rename remoteDomainReadEvent() to remoteDomainReadEventLifecycle()
* src/remote/remote_protocol.x: Define wire format for the new
  virConnectDomainEventRegisterAny and virConnectDomainEventDeregisterAny
  functions

* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done

The 'int virInterfaceIsActive()' method was directly returning the
value of the 'int active:1' bitfield in virIntefaceDefPtr. A bitfield
with a signed integer, will hold the values 0 and -1, not 0 and +1
as might be expected. This meant that virInterfaceIsActive() was
always returning -1 when the interface was active, not +1 & thus all
callers thought an error had occurred. To protect against this kind
of mistake again, change all bitfields to be unsigned ints

* daemon/libvirtd.h, src/conf/domain_conf.h, src/conf/interface_conf.h,
  src/conf/network_conf.h: Change bitfields to unsigned int.

The daemon will attempt to unregister domain events on client disconnect,
even if no events were ever registered. This raises an unneeded error.

Track in the qemu_client structure if events have been registered, and
check this when performing cleanup.

The virStateInitialize() call for starting up stateful drivers
may require that the event loop is running already. This it is
neccessary to start the event loop before this call. At the
same time, network clients must not be processed until afte
virStateInitialize has completed.

The qemudListenUnix() and remoteListenTCP() methods must
therefore not register file handle watches, merely open the
network sockets & listen() on them. This means clients can
connected and are queued, pending completion of initialization

The qemudRunLoop() method is moved into a background thread
that is started early to allow access to the event loop during
driver initialization. The main process thread leader pretty
much does nothing once the daemon is running, merely waits
for the event loop thread to quit

* daemon/libvirtd.c, daemon/libvirtd.h: Move event loop into
  a background thread
* daemon/THREADING.txt: Rewrite docs to better reflect reality

* daemon/libvirtd.c: Introduce a daemonSetupSignals() method
  and put all signal handling code there
* daemon/libvirtd.h: Add sigread/sigwrite to qemud_server type

* daemon/dispatch.c: Set streamTX flag on outgoing data packets
* daemon/qemud.h: Add streamTX flag to track outgoing data
* daemon/qemud.c: Re-enable further TX when outgoing data packet
  has been fully sent.
* daemon/stream.h, daemon/stream.c: Add method for enabling TX.
  Support reading from streams and transmitting data out to client

Defines the extensions to the remote protocol for generic
data streams. Adds a bunch of helper code to the libvirtd
daemon for working with data streams.

* daemon/Makefile.am: Add stream.c/stream.h to build
* daemon/stream.c, qemud/stream.h: Generic helper functions for
  creating new streams, associating streams with clients, finding
  existing streams for a client and removing/deleting streams.
* src/remote/remote_protocol.x: Add a new 'REMOTE_STREAM' constant
  for the 'enum remote_message_type' for encoding stream data
  in wire messages. Add a new 'REMOTE_CONTINUE' constant to
  'enum remote_message_status' to indicate further data stream
  messsages are expected to follow.  Document how the
  remote_message_header is used to encode data streams
* src/remote/remote_protocol.h: Regenerate
* daemon/dispatch.c: Remove assumption that a error message
  sent to client is always type=REMOTE_REPLY. It may now
  also be type=REMOTE_STREAM. Add convenient method for
  sending outgoing stream data packets. Log and ignore
  non-filtered incoming stream packets. Add a method for
  serializing a stream error message
* daemon/dispatch.h:  Add API for serializing stream errors
  and sending stream data packets
* daemon/qemud.h: Add struct qemud_client_stream for tracking
  active data streams for clients. Tweak filter function
  operation so that it accepts a client object too.
* daemon/qemud.c: Refactor code for free'ing message objects
  which have been fully transmitted into separate method.
  Release all active streams when client shuts down. Change
  filter function to be responsible for queueing the message

* daemon/qemud.c: Rename to daemon/libvirtd.c
* daemon/qemud.h: Rename to daemon/libvirtd.h
* daemon/Makefile.am, daemon/dispatch.h, daemon/mdns.c,
  daemon/remote.h: Update for renamed libvirtd.h file

* qemud/: Rename to daemon/
* Makefile.am, configure.in, src/Makefile.am, src/remote_internal.c,
  tests/Makefile.am, tests/eventtest.c: s/qemud/daemon/ where needed

* configure.in: Check for pkcheck which indicates new policykit
* qemud/Makefile.am: Install different versions of policy
* qemud/libvirtd.policy: Rename to libvirtd.policy-0
* qemud/libvirtd.policy-1: new style policy
* qemud/qemud.c, qemud/qemud.h, qemud/remote.c: Support new
  policykit API via external pkcheck helper
* src/remote_internal.c: Don't prompt for polkit auth with new
  policykit API
* libvirt.spec.in: deal with new policy install locations & deps

GCC >= 4.4 assumes the 'printf' attribute refers to the native
runtime libraries format specifiers. Thanks to gnulib, libvirt
has GNU format specifiers everywhere.  This means we need to
use 'gnu_printf' with GCC >= 4.4 to get correct compiler
checking of printf format specifiers.

* HACKING: Document new rules for ATTRIBUTE_FMT_PRINTF
* autobuild.sh, mingw32-libvirt.spec.in: Disable OpenNebula
  driver on mingw32 builds
* qemud/dispatch.h, qemud/qemu.h, src/buf.h src/internal.h,
  src/logging.h, src/security.h, src/sexpr.h, src/util.h,
  src/virterror_internal.h, src/xend_internal.c: Change
  over to ATTRIBUTE_FMT_PRINTF.
* src/virsh.c: Disable 'cd' and 'pwd' commands on Win32
  since they don't compile
* src/threads-win32.c: Add missing return value check

All incoming messages currently get routed to the generic method
remoteDispatchClientRequest() for processing. To allow incoming
data stream messages to bypass this and be routed to a specific
location, a concept of dispatch filters is introduced.

* qemud/qemud.h: Add a qemud_client_filter struct and a callback
  qemud_client_filter_func. Maintain a list of filters on every
  struct qemud_client
* qemud/qemud.c: Move remoteDecodeClientMessageHeader() out of
  qemudWorker() into qemudDispatchClientRead(). Check registered
  message filters in qemudDispatchClientRead() to decide where
  to send incoming messages for dispatch.

The current qemudRegisterClientEvent() code is used both for
registering the initial socket watch, and updating the already
registered watch. This causes unneccessary complexity in alot
of code which only cares about updating existing watches. The
updating of a watch cannot ever fail, nor is a reference to the
'qemud_server' object required.

This introduces a new qemudUpdateClientEvent() method for that
case, allowing the elimination of unneccessary error checking
and removal of the server back-reference in struct qemud_client.

* qemud/qemud.h: Remove 'server' field from struct qemud_client.
  Add qemudUpdateClientEvent() method. Remove 'update' param
  from qemudRegisterClientEvent method
* qemud/dispatch.c, qemud/qemud.c, qemud/remote.c: Update alot
  of code to use qemudUpdateClientEvent() instead of
  qemudRegisterClientEvent(). Move more logic from remoteRelayDomainEvent
  into remoteDispatchDomainEventSend.

Separate the decoding of incoming request header out from the
dispatch code. This will allow later code to making dispatcher
routing decisions based on the header field data.

* qemud/dispatch.c, qemud/dispatch.h: Add remoteDecodeClientMessageHeader
  API for decoding the header of a client message. Update the
  remoteDispatchClientRequest method to assume a pre-decoded
  header.
* qemud/qemud.h: Include a 'remote_message_header' field in
  'struct qemud_client_message' for pre-decoded header data
* qemud/qemud.c: Decode the incoming client message header before
  invoking remoteDispatchClientRequest

* po/POTFILES.in: Add qemud/dispatch.c
* qemud/dispatch.c, qemud/dispatch.h: Generic code handling dispatch of
  RPC messages.
* qemud/Makefile.am: Add dispatch.c to build
* qemud/qemud.c: Include dispatch.h
* qemud/qemud.h: Remove remoteDispatchClientRequest, remoteRelayDomainEvent
  now in dispatch.h
* qemud/remote.c: Remove remoteDispatchClientRequest, remoteRelayDomainEvent
  now in dispatch.c, and dispatch_args, dispatch_ret, dispatch_fn & dispatch_data
  now in remote.h
* qemud/remote.h: Add typedefs for dispatch_args, dispatch_ret,
  dispatch_fn, dispath_data. Add remoteGetDispatchData() API

Before this change, the unix socket directory was hard-coded
to be e.g., /var/run/libvirt for euid==0 and ~/.libvirt otherwise.
With this change, you may now specify that directory in libvirtd's
config file via a line like this: unix_sock_dir = "/var/run/libvirt".
This is essential for running tests that do not impinge on any
existing libvirtd process, and in running tests in parallel.
* qemud/libvirtd.conf (unix_sock_dir): Add comment and example.
* qemud/qemud.h (struct qemud_server) [logDir]: Change type
from char[PATH_MAX] to char*.
* qemud/qemud.c (unix_sock_dir): New global
(remoteReadConfigFile): Set the global.
(qemudInitPaths): Use the global, unix_sock_dir, if non-NULL.
One minor improvement: unlink both sockets or none, never
just one of them.
(qemudCleanup): Free logDir.
(main): Use the new global rather than hard-coding "/run/libvirt".
* qemud/libvirtd.aug (sock_acl_entry): Add "unix_sock_dir".

* qemud/qemud.c qemud/qemud.h: replace the daemon old logging
  infrastructure with the new one and parse configuration options
daniel