Introduce virDomainPMWakeup API

This API allows a domain which previously called
virDomainPMSuspendForDuration() to be woken up.
virsh: Expose virDomainPMWakeup
qemu: Implement virDomainPMWakeup API

using 'system-wakeup' monitor command. It is supported only in JSON,
as we are enabling it if possible. Moreover, this command is available
in qemu-1.1+ which definitely has JSON.
pidfile: Make checking binary path in virPidFileRead optional

This patch changes behavior of virPidFileRead to enable passing NULL as
path to the binary the pid file should be checked against to skip this
check. This enables using this function for reading files that have same
semantics as pid files, but belong to unknown processes.
Add flags for virDomainOpenConsole

This patch adds a set of flags to be used with the virDomainOpenConsole
API call to specify if the user wishes to interrupt an existing console
session or just to try open a new one.

VIR_DOMAIN_CONSOLE_SAFE - specifies that the console connection should
                          be opened only if the hypervisor supports
                          mutually exclusive access to console devices

VIR_DOMAIN_CONSOLE_FORCE - specifies that the caller wishes to interrupt
                           existing session and force a creation of a
                           new one.
virsh: add support for VIR_DOMAIN_CONSOLE_* flags

This patch adds support for the newly introduced
VIR_DOMAIN_CONSOLE_FORCE and VIR_DOMAIN_CONSOLE_SAFE flags. The console
command now has an optional parameter --force that specifies that the
user wants to forcibly interrupt an ongoing console session and create
a new one. Flag --safe requests that the console should be opened only
if the hypervisor driver supports safe console handling.

The behaviour to this point was that the daemon opened two streams to
the console, that competed for data from the pipe, and the result was
that both of the consoles ended up scrambled.

This patch doesn't modify operation of other commands dealing with
console connections (start, create) as those open connections to newly
started domains making it virtually impossible for another client to race
for the console and steal it.

* tools/console.c:
        - add support for flag passthrough
* tools/console.h:
        - modify function prototypes to match impl.
* tools/virsh.c:
        - add flag --force for the console command
fdstream: Emit stream abort callback even if poll() doesnt.

This patch causes the fdstream driver to call the stream event callback
if virStreamAbort() is called on a stream using this driver.

A remote handler for a stream can only detect changes via stream events,
so this event callback is necessary in order to enable a daemon to abort
a stream in such a way that the client will see the change.

* src/fdstream.c:
        - modify close function to call stream event callback
fdstream: Add internal callback on stream close

This patch adds another callback to a FDstream object. The original
callback is used by the daemon stream driver to handle events.

This callback is called if and only if the stream is about to be closed.
This might be used to handle cleanup steps after a fdstream exits. This
will be used later on in ensuring mutually exclusive access to consoles.

* src/fdstream.c:
        - emit the callback, when stream is being closed
        - add data structures needed to handle the callback
        - add function to register callback
* src/fdstream.h:
        - define function prototypes for the callback
util: Add helpers for safe domain console operations

This patch adds a set of functions used in creating console streams for
domains using PTYs and ensures mutually exclusive access to the PTYs.

If mutually exclusive access is not used, two clients may open the same
console, which results in corruption on both clients as both of them
race to read data from the PTY.

Two approaches are used to ensure this:
1) Internal data structure holding open PTYs.
        This is used internally and enables the user to forcibly
        terminate another console connection eg. when somebody leaves
        the console open on another host.

2) UUCP style lock files:
        This uses UUCP lock files according to the  FHS
        ( http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLOCKLOCKFILES )
        to check if other programs (like minicom) are not using the pty
        device of the console.

        This feature is disabled by default and may be enabled using
        configure parameter
        --with-console-lock-files=/path/to/lock/file/directory
        or --with-console-lock-files=auto (which tries to infer the
        location from OS used (currently only linux).

        On usual linux systems, normal users may not write to the
        /var/lock directory containing the locks. This poses problems
        while in session mode. If the current user has no access to the
        lockfile directory, check for presence of the file is still
        done, but no lock file is created. This does NOT result in an
        error.
qemu: Add ability to abort existing console while creating new one

This patch fixes console corruption, that happens if two concurrent
sessions are opened for a single console on a domain. Result of this
corruption was that each of the console streams recieved just a part
of the data written to the pipe so every console rendered unusable.

New helper function for safe console handling is used to establish the
console stream connection. This function ensures that no other libvirt
client is using the console (with the ability to disconnect consoles of
libvirt clients) and that no UUCP style lockfile is placed on the PTY
device.

* src/qemu/qemu_domain.h
        - add data structure to domain's private data dealing with
          console connections
* src/qemu/qemu_domain.c:
        - allocate/free domain's console data structure
* src/qemu/qemu_driver.c
        - use the new helper function for console handling
qemu: unescape HMP commands before converting them to json

QMP commands don't need to be escaped since converting them to json
also escapes special characters. When a QMP command fails, however,
libvirt falls back to HMP commands. These fallback functions
(qemuMonitorText*) do their own escaping, and pass the result directly
to qemuMonitorHMPCommandWithFd. If the monitor is in json mode, these
pre-escaped commands will be escaped again when converted to json,
which can result in the wrong arguments being sent.

For example, a filename test\file would be sent in json as
test\\file.

This prevented attaching an image file with a " or \ in its name in
qemu 1.0.50, and also broke rbd attachment (which uses backslashes to
escape some internal arguments.)

Reported-by: Masuko Tomoya <tomoya.masuko@gmail.com>
Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
qemu: fix cleanup of bridge during failure of qemuDomainAttachNetDevice

In qemuDomainAttachNetDevice, the guest's tap interface has only been
attached to the bridge if iface_connected is true. It's possible for
an error to occur prior to that happening, and previously we would
attempt to remove the tap interface from the bridge even if it hadn't
been attached.
qemu: add ibmvscsi controller model

KVM will be able to use a PCI SCSI controller even on POWER.  Let
the user specify the vSCSI controller by other means than a default.

After this patch, the QEMU driver will actually look at the model
and reject anything but auto, lsilogic and ibmvscsi.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Osier Yang <jyang@redhat.com>
qemu: add virtio-scsi controller model

Adding a new model for virtio-scsi roughly follows the same scheme
as the previous patch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
conf: Add helper function to look up disk controller model
conf: Introduce new attribute for device address format

* src/conf/domain_conf.h: Add new member "target" to struct
  _virDomainDeviceDriveAddress.

* src/conf/domain_conf.c: Parse and format "target"

* Lots of tests (.xml) in tests/domainsnapshotxml2xmlout,
  tests/qemuxml2argvdata, tests/qemuxml2xmloutdata, and
  tests/vmx2xmldata/ are modified for newly introduced
  attribute "target" for address of "drive" type.
qemu: New cap flag to indicate if channel is supported by scsi-disk
qemu: Build command line for the new address format

For any disk controller model which is not "lsilogic", the command
line will be like:

  -drive file=/dev/sda,if=none,id=drive-scsi0-0-3-0,format=raw \
  -device scsi-disk,bus=scsi0.0,channel=0,scsi-id=3,lun=0,i\
  drive=drive-scsi0-0-3-0,id=scsi0-0-3-0

The relationship between the libvirt address attrs and the qdev
properties are (controller model is not "lsilogic"; strings
inside <> represent libvirt adress attrs):
  bus=scsi<controller>.0
  channel=<bus>
  scsi-id=<target>
  lun=<unit>

* src/qemu/qemu_command.h: (New param "virDomainDefPtr def"
  for function qemuBuildDriveDevStr; new param "virDomainDefPtr
  vmdef" for function qemuAssignDeviceDiskAlias. Both for
  virDomainDiskFindControllerModel's use).

* src/qemu/qemu_command.c:
  - New param "virDomainDefPtr def" for qemuAssignDeviceDiskAliasCustom.
    For virDomainDiskFindControllerModel's use, if the disk bus is "scsi"
    and the controller model is not "lsilogic", "target" is one part of
    the alias name.
  - According change on qemuAssignDeviceDiskAlias and qemuBuildDriveDevStr

* src/qemu/qemu_hotplug.c:
  - Changes to be consistent with declarations of qemuAssignDeviceDiskAlias
    qemuBuildDriveDevStr, and qemuBuildControllerDevStr.

* tests/qemuxml2argvdata/qemuxml2argv-pseries-vio-user-assigned.args,
  tests/qemuxml2argvdata/qemuxml2argv-pseries-vio.args: Update the
  generated command line.
tests: Add tests for virtio-scsi and ibmvscsi controllers
virsh: Two new helper functions for disk device changes

vshFindDisk is to find the disk node in xml doc with given source
path or target of disk device, and type (indicates disk type,
normal disk or changeable disk).

vshPrepareDiskXML is to make changes on the disk node (e.g. create
and insert the new <source> node for inserting media of CDROM drive).

They are marked as unused temporarily.