Switch from using write() to using sendmsg() on QEMU's monitor socket
so that we can add support for SCM_RIGHTS.

* src/qemu_driver.c: add sendmsg() based qemudMonitorSendUnix() and use
  it when the monitor fd is a unix socket

Add a little helper function to write the monitor command followed by
carriage return in a single write.

This doesn't make any real difference, but allows us to more easily
switch to using sendmsg() when using the monitor over a unix socket.

* src/qemu_conf.c: split qemudMonitorSend() out

In subsequent patches we're going to have a file descriptor to close
too, so centralize the error handling cleanups to make things easier.

* src/qemu_conf.c: in qemudDomainAttachNetDevice() consolidate the
  error handling cleanups together

With hotplug, we're going to want to pass a tapfd name rather than an
actual file descriptor, so prepare the way by passing a string tapfd to
qemuBuildHostNetStr().

* src/qemu_conf.h: qemuBuildHostNetStr() takes a string tapfd now

* src/qemu_conf.c: pass qemuBuildHostNetStr() a string rather than an
  actual file descriptor

* src/qemu_driver.c: update qemudDomainAttachNetDevice() for change

By probing for qemu machine types, we increased the time of a
GetCapabilities call from 100us to a whopping 60ms.

This patch takes the approach of only probing for machine types
when the mtime of the emulator binary changed since the last time
the capabilities were generated.

* src/capabilities.h: cache the emulator binary mtime

* src/qemu_conf.c: add qemudGetOldMachines() to copy the machine
  types from the old caps struct if the mtime for the binary hasn't
  changed

* src/qemu_conf.h, src/qemu_driver.c: pass the old caps pointer to
  qemudCapsInit()

Not all possible emulators are actually in the capabilities, so if we
don't find the supplied emulator we should probe it directly for machine
types.

* src/qemu_driver.c: add qemudCanonicalizeMachineDirect() to directly
  probe an emulator for the canonical machine type

In qemu-0.11 there is a 'pc-0.10' machine type which allows you to run
guests with a machine which is compatible with the pc machine in
qemu-0.10 - e.g. using the original PCI class for virtio-blk and
virtio-console and disabling MSI support in virtio-net. The idea here
is that we don't want to suprise guests by changing the hardware when
qemu is updated.

I've just posted some patches for qemu-0.11 which allows libvirt to
canonicalize the 'pc' machine alias to the latest machine version.

This patches makes us use that so that when a guest is configured to
use the 'pc' machine type, we resolve that to 'pc-0.11' machine and
save that in the guest XML.

See also:

  https://fedoraproject.org/wiki/Features/KVM_Stable_Guest_ABI

* src/qemu_conf.c: add qemudCanonicalizeMachine() to canonicalize
  the machine type according to the machine aliases in capabilities

* src/qemu_driver.c: parse aliases in qemudParseMachineTypesStr()

Do the check in libvirt.c, to save drivers from the burden. This changes
behavior slightly in the qemu driver: we no longer explictly error if
passed an empty string. An error will still be thrown when the device
lookup fails.

 * qemud/libvirtd_qemu.aug, qemud/test_libvirtd_qemu.aug,
   src/qemu.conf: Add 'cgroups_controllers' and 'cgroups_device_acl'
   parameters
 * src/qemu_conf.h, src/qemu_conf.c: Load & parse configuration params
   for cgroups
 * src/qemu_driver.c: Only use cgroups controllers that are activated,
   and use configured device whitelist instead of default, if set.

* src/qemu_driver.c: Set a restrictive block device whitelist for
  all QEMU guests. Update whitelist when hotplugging disks.
* src/cgroup.h, src/cgroup.c: Add some more convenience methods
  for dealing with block device whitelists.

* src/qemu_driver.c:  Add driver methods qemuGetSchedulerType,
  qemuGetSchedulerParameters, qemuSetSchedulerParameters
* src/lxc_driver.c: Fix to use unsigned long long consistently
  for schedular parameters
* src/cgroup.h, src/cgroup.c: Fix cpu_shares to take unsigned
  long long
* src/util.c, src/util.h, src/libvirt_private.syms: Add a
  virStrToDouble helper
* src/virsh.c: Fix handling of --set arg to schedinfo command
  to honour the designated data type of each schedular tunable
  as declared by the driver

* src/qemu_driver.c: Place guest in cgroup upon startup. Remove
  cgroup upon shutdown

* src/datatypes.c src/domain_conf.c src/interface_conf.c
  src/lxc_driver.c src/qemu_driver.c src/storage_backend.c src/virsh.c:
  add bare %s format string to printf-derivatives called with no format
  string

* include/libvirt/libvirt.h include/libvirt/libvirt.h.in: adds the new
  flag VIR_MEMORY_PHYSICAL for virDomainMemoryPeek
* src/libvirt.c: update the front-end checking
* src/qemu_driver.c: extend the QEmu driver

qemu network devices are hot-unplugged in two stages - first the PCI NIC
is removed using 'pci_del <pci_addr>' and then the backend is removed
using 'host_net_remove <vlan> <name>'.

In order to perform these operations we need to have retained the
PCI address, backend name and vlan number.

* src/qemu_driver.c: add qemudDomainDetachNetDevice()

When we pci_add a NIC, we need to retain the PCI address assigned by
qemu for using during detach.

* src/qemu_driver.c: use qemudParsePciAddReply() to pull the PCI
  address from the pci_add reply

* src/domain_conf.c: handle storing and parsing the PCI address in the
  domain state XML file

The current code for parsing pci_add replies ignores the the domain and
bus numbers. Re-write the code to rectify that.

Also, since pci_add is used for NIC hotplug as well ask disk hotplug,
re-factor the code into a separate function.

* src/qemu_driver.c: add qemudParsePciAddReply() function which can
  handle parsing domain and bus numbers

If we fail to pci_add a NIC, we should remove the network backend and
leave things the way we found them. To do that, we pre-allocate a
host_net_remove monitor command and issue that if the pci_add fails.
If the remove fails, we just log a warning.

We can only do this if we have a name for the network backend and
we know the vlan number its associated with.

* src/qemu_driver.c: host_net_remove the network backend if the
  pci_add fails

Implement basic NIC hotplug support using the 'host_net_add' and
'pci_add' qemu monitor commands.

For now, we don't support 'bridge' or 'network' types.

Also, if pci_add fails, we currently fail to remove the backend
which we added.

Finally, NIC hot-unplug support is missing.

* src/qemu_driver.c: add qemudDomainAttachNetDevice()

* src/qemu_conf.[ch]: export qemuBuildNicStr(), qemuBuildHostNetStr()
  and qemuAssignNames()

* src/libvirt_private.syms: export virDomainNetTypeToString()

qemudDomainChangeEjectableMedia() currently extracts the qemu command
line flags, but other device attaching code might need it, so move
the qemudExtractVersionInfo() call up a frame.

* src/qemu_driver.c: move the qemudExtractVersionInfo() call from
  qemudDomainChangeEjectableMedia() to qemudDomainAttachDevice()

When we hot-plug a disk device into a qemu guest, we need to retain its
PCI address so that it can be removed again later. Currently, we do
retain the slot number, but not across libvirtd restarts.

Add <state devaddr="xxxx:xx:xx"/> to the disk device XML config when the
VIR_DOMAIN_XML_INTERNAL_STATUS flag is used. We still don't parse the
domain and bus number, but the format allows us to do that in future.

* src/domain_conf.h: replace slotnum with pci_addr struct, add helper
  for testing whether the address is valid

* src/domain_conf.c: handle formatting and parsing the address

* src/qemu_driver.c: store the parsed slot number as a full PCI address,
  and use this address with the pci_del monitor command

* src/vbox/vbox_tmpl.c: we're debug printing slotnum here even though
  it can never be set, just delete it

* src/qemu_driver.c: qemudOpenMonitorUnix() had an uninitialized loop
  counter

Unlike the pty monitor (which we know exists since we scrape its path from
stdout), we have no way of knowing that the unix monitor socket should exist/
be initialized. As a result, some of my KVM guests randomly fail to start on
F10 host.

Try to open the unix socket in a 3 second timeout loop. Ignore EACCES (path
does not exist if a first time run) and ECONNREFUSED (leftover socket from
a previous run hasn't been removed yet). Fixes things for me.

* configure.in: Add --with-qemu-user and --with-qemu-group args
* libvirt.spec.in: use 'qemu' for user/group for Fedora >= 12
* qemud/libvirtd_qemu.arg, qemud/test_libvirtd_qemu.aug,
  src/qemu.conf: Add 'user' and 'group' args for configuration
* src/Makefile.am: Create %localstatedir/cache/libvirt/qemu
* src/qemu_conf.c, src/qemu_conf.h: Load user/group from config
* src/qemu_driver.c: Change user ID/group ID when launching QEMU
  guests. Change user/group ownership on disks/usb/pci devs.
  Put memory dumps in %localstatedir/cache/libvirt/qemu
* src/util.c, src/util.h: Add convenient APIs for converting
  username/groupname to user ID / group ID

* src/qemu_driver.c (qemudDomainCoreDump): New
  (qemuDriver): Add core dump function. The behaviour is similar
  as the current Xen dump

* src/qemu_driver.c: Relabel disk images *before* running QEMU
hotplug monitor commands

* src/qemu_driver.c: Try new monitor syntax for hotplug first. If
  that fails fallback to old KVM specific syntax

after a libvirtd daemon restart with active guests

* src/qemu_driver: Read and dicard pending monitor data
  before issuing new monitor commands.

If the qemu_driver was not initialized (possibly due to an error on driver
startup), we can segfault if attempting to connect to the URI.

We keep support for the pty based monitor so that we can re-connect
to VMs started by older versions of libvirtd.

* src/domain_conf.c: handle formatting and parsing unix monitors

* src/qemu_driver.c: add qemudOpenMonitorUnix(), remove the monitor
  pty path searching from qemudFindCharDevicePTYs(), switch
  qemudStartVMDaemon() and qemuDomainXMLToNative() to using a unix
  monitor

* tests/qemuxml2argvtest.c: switch to using a unix monitor

* tests/qemuxml2argvdata/qemuxml2argv-*.args: update test data

There are no functional changes in this patch apart from adding the
monitor type to the state XML.

The patch mostly consists of switching to use virDomainChrDef every
where to describe the monitor.

* src/domain_conf.h: replace monitorpath with monitor_chr

* src/domain_conf.c: handle parsing the monitor type and initializing
  monitor chr

* src/qemu_conf.[ch]: make qemudBuildCommandLine take a
  virDomainChrDefPtr and use that to build the -monitor parameter

* src/qemu_driver.c: split pty specific and common code from
  qemudOpenMonitor, have qemudStartVMDaemon() initialize monitor_chr

* tests/qemuxml2argvtest.c: update for qemudBuildCommandLine() change

* src/qemu_driver.c: use a consistent coding style for function
  definitions

* src/qemu_driver.c: vm->monitorpath is already initialized in the case
  of re-connect, so move the initialization for the normal startup case
  out of the common code

* src/qemu_driver.c: fix a domain state problem after
  migration, patch  by Federico Simoncelli, fixes #507537
* src/domain_conf.c:  fix a transcient domain state problem after
  destroy, patch  by Federico Simoncelli, fixes #507304
* AUTHORS: add Federico Simoncelli and Javier Fontan
daniel

Currently, 'info' will always report that mem = max mem. Make sure we
actually return the correct mem value.

Rather than numerous instances of:

emulator = vm->def->emulator;
if (!emulator)
    emulator = virDomainDefDefaultEmulator(conn, vm->def, driver->caps);
if (!emulator)
    return -1;

Set this value at XML parse time in the domain config, so we can depend on
it for all future emulator accesses. There were unchecked accesses in the
qemu driver that were tripping up on this if no emulator was specified in
the XML, see:

http://www.redhat.com/archives/libvir-list/2008-October/msg00602.html