virFileOpenAs previously would only try opening a file as the current
user, or as a different user, but wouldn't try both methods in a
single call. This made it cumbersome to use as a replacement for
open(2). Additionally, it had a lot of historical baggage that led to
it being difficult to understand.

This patch refactors virFileOpenAs in the following ways:

* reorganize the code so that everything dealing with both the parent
  and child sides of the "fork+setuid+setgid+open" method are in a
  separate function. This makes the public function easier to understand.

* Allow a single call to virFileOpenAs() to first attempt the open as
  the current user, and if that fails to automatically re-try after
  doing fork+setuid (if deemed appropriate, i.e. errno indicates it
  would now be successful, and the file is on a networkFS). This makes
  it possible (in many, but possibly not all, cases) to drop-in
  virFileOpenAs() as a replacement for open(2).

  (NB: currently qemuOpenFile() calls virFileOpenAs() twice, once
  without forking, then again with forking. That unfortunately can't
  be changed without at least some discussion of the ramifications,
  because the requested file permissions are different in each case,
  which is something that a single call to virFileOpenAs() can't deal
  with.)

* Add a flag so that any fchown() of the file to a different uid:gid
  is explicitly requested when the function is called, rather than it
  being implied by the presence of the O_CREAT flag. This just makes
  for less subtle surprises to consumers. (Commit
  b1643dc1 added the check for O_CREAT
  before forcing ownership. This patch just makes that restriction
  more explicit.)

* If either the uid or gid is specified as "-1", virFileOpenAs will
  interpret this to mean "the current [gu]id".

All current consumers of virFileOpenAs should retain their present
behavior (after a few minor changes to their setup code and
arguments).

When libvirt's virDomainDestroy API is shutting down the qemu process,
it first sends SIGTERM, then waits for 1.6 seconds and, if it sees the
process still there, sends a SIGKILL.

There have been reports that this behavior can lead to data loss
because the guest running in qemu doesn't have time to flush its disk
cache buffers before it's unceremoniously whacked.

This patch maintains that default behavior, but provides a new flag
VIR_DOMAIN_DESTROY_GRACEFUL to alter the behavior. If this flag is set
in the call to virDomainDestroyFlags, SIGKILL will never be sent to
the qemu process; instead, if the timeout is reached and the qemu
process still exists, virDomainDestroy will return an error.

Once this patch is in, the recommended method for applications to call
virDomainDestroyFlags will be with VIR_DOMAIN_DESTROY_GRACEFUL
included. If that fails, then the application can decide if and when
to call virDomainDestroyFlags again without
VIR_DOMAIN_DESTROY_GRACEFUL (to force the issue with SIGKILL).

(Note that this does not address the issue of existing applications
that have not yet been modified to use VIR_DOMAIN_DESTROY_GRACEFUL.
That is a separate patch.)

Added RSS information gathering into qemuMemoryStats into qemu driver
and the reporting into virsh dommemstat.

One more parameter added into the function parsing /proc/<pid>/stat
and the call of the function is fixed as well.

Curently security labels can be of type 'dynamic' or 'static'.
If no security label is given, then 'dynamic' is assumed. The
current code takes advantage of this default, and avoids even
saving <seclabel> elements with type='dynamic' to disk. This
means if you temporarily change security driver, the guests
can all still start.

With the introduction of sVirt to LXC though, there needs to be
a new default of 'none' to allow unconfined LXC containers.

This patch introduces two new security label types

 - default:  the host configuration decides whether to run the
             guest with type 'none' or 'dynamic' at guest start
 - none:     the guest will run unconfined by security policy

The 'none' label type will obviously be undesirable for some
deployments, so a new qemu.conf option allows a host admin to
mandate confined guests. It is also possible to turn off default
confinement

  security_default_confined = 1|0  (default == 1)
  security_require_confined = 1|0  (default == 0)

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add new
  seclabel types
* src/security/security_manager.c, src/security/security_manager.h:
  Set default sec label types
* src/security/security_selinux.c: Handle 'none' seclabel type
* src/qemu/qemu.conf, src/qemu/qemu_conf.c, src/qemu/qemu_conf.h,
  src/qemu/libvirtd_qemu.aug: New security config options
* src/qemu/qemu_driver.c: Tell security driver about default
  config

This is a trivial implementation, which works with the current
released qemu 1.0 with backports of preliminary block pull but
no partial rebase.  Future patches will update the monitor handling
to support an optional parameter for partial rebase; but as qemu
1.1 is unreleased, it can be in later patches, designed to be
backported on top of the supported API.

* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Add parameter,
and adjust callers.  Drop redundant check.
(qemuDomainBlockPull): Move guts...
(qemuDomainBlockRebase): ...to new function.

This patch adds support for the new api into the qemu driver to support
modification and retrieval of domain description and title. This patch
does not add support for modifying the <metadata> element.

which contained some useless lines, copied code, NULL
dereference.

In qemuDomainShutdownFlags if we try to use guest agent,
which has error or is not configured, we jump go endjob
label even if we haven't started any job yet. This may
lead to the daemon crash:
1) virsh shutdown --mode agent on a domain without agent configured
2) wait until domain quits
3) virsh edit

To help consolidate the commonality between virDomainHostdevDef and
virDomainNetDef into as few members as possible (and because I
think it makes sense), this patch moves the rombar and bootIndex
members into the "info" member that is common to both (and to all the
other structs that use them).

It's a bit problematic that this gives rombar and bootIndex to many
device types that don't use them, but this is already the case for the
master and mastertype members of virDomainDeviceInfo, and is properly
commented as such in the definition.

Note that this opens the door to supporting rombar for other devices
that are attached to the guest PCI bus - virtio-blk-pci,
virtio-net-pci, various other network adapters - which which have that
capability in qemu, but previously had no support in libvirt.

Rename virFormatMacAddr, virGenerateMacAddr and virParseMacAddr
to virMacAddrFormat, virMacAddrGenerate and virMacAddrParse
respectively

With this flag, virDomainSnapshotCreate will use fs-freeze and
fs-thaw guest agent commands to quiesce guest's disks.

This makes use of the QEMU guest agent to implement the
virDomainShutdownFlags and virDomainReboot APIs. With
no flags specified, it will prefer to use the agent, but
fallback to ACPI. Explicit choice can be made by using
a suitable flag

* src/qemu/qemu_driver.c: Wire up use of agent

Reusing common code makes things smaller; it also buys us some
additional safety, such as now rejecting duplicate parameters
during a set operation.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters)
(qemuDomainSetMemoryParameters, qemuDomainSetNumaParameters)
(qemuSetSchedulerParametersFlags)
(qemuDomainSetInterfaceParameters, qemuDomainSetBlockIoTune)
(qemuDomainGetBlkioParameters, qemuDomainGetMemoryParameters)
(qemuDomainGetNumaParameters, qemuGetSchedulerParametersFlags)
(qemuDomainBlockStatsFlags, qemuDomainGetInterfaceParameters)
(qemuDomainGetBlockIoTune): Use new helpers.
* src/esx/esx_driver.c (esxDomainSetSchedulerParametersFlags)
(esxDomainSetMemoryParameters)
(esxDomainGetSchedulerParametersFlags)
(esxDomainGetMemoryParameters): Likewise.
* src/libxl/libxl_driver.c
(libxlDomainSetSchedulerParametersFlags)
(libxlDomainGetSchedulerParametersFlags): Likewise.
* src/lxc/lxc_driver.c (lxcDomainSetMemoryParameters)
(lxcSetSchedulerParametersFlags, lxcDomainSetBlkioParameters)
(lxcDomainGetMemoryParameters, lxcGetSchedulerParametersFlags)
(lxcDomainGetBlkioParameters): Likewise.
* src/test/test_driver.c (testDomainSetSchedulerParamsFlags)
(testDomainGetSchedulerParamsFlags): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorSetSchedulerParameters)
(xenHypervisorGetSchedulerParameters): Likewise.

It doesn't make sense to reattach a device to host while it's
still in use, e.g, by a domain.

pciTrySecondaryBusReset checks if there is active device on the
same bus, however, qemu driver doesn't maintain an effective
list for the inactive devices, and it passes meaningless argument
for parameter "inactiveDevs". e.g. (qemuPrepareHostdevPCIDevices)

if (!(pcidevs = qemuGetPciHostDeviceList(hostdevs, nhostdevs)))
    return -1;

..skipped...

if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0)
    goto reattachdevs;

NB, the "pcidevs" used above are extracted from domain def, and
thus one won't be able to attach a device of which bus has other
device even detached from host (nodedev-detach). To see more
details of the problem:

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=773667

This patch is to resolve the problem by introducing an inactive
PCI device list (just like qemu_driver->activePciHostdevs), and
the whole logic is:

  * Add the device to inactive list during nodedev-dettach
  * Remove the device from inactive list during nodedev-reattach
  * Remove the device from inactive list during attach-device
    (for non-managed device)
  * Add the device to inactive list after detach-device, only
    if the device is not managed

With the above, we have a sufficient inactive PCI device list, and thus
we can use it for pciResetDevice. e.g.(qemuPrepareHostdevPCIDevices)

if (pciResetDevice(dev, driver->activePciHostdevs,
                   driver->inactivePciHostdevs) < 0)
    goto reattachdevs;

When sVirt is integrated with the LXC driver, it will be neccessary
to invoke the security driver APIs using only a virDomainDefPtr
since the lxc_container.c code has no virDomainObjPtr available.
Aside from two functions which want obj->pid, every bit of the
security driver code only touches obj->def. So we don't need to
pass a virDomainObjPtr into the security drivers, a virDomainDefPtr
is sufficient. Two functions also gain a 'pid_t pid' argument.

* src/qemu/qemu_driver.c, src/qemu/qemu_hotplug.c,
  src/qemu/qemu_migration.c, src/qemu/qemu_process.c,
  src/security/security_apparmor.c,
  src/security/security_dac.c,
  src/security/security_driver.h,
  src/security/security_manager.c,
  src/security/security_manager.h,
  src/security/security_nop.c,
  src/security/security_selinux.c,
  src/security/security_stack.c: Change all security APIs to use a
  virDomainDefPtr instead of virDomainObjPtr

When disk snapshots were first implemented, libvirt blindly refused
to allow an external snapshot destination that already exists, since
qemu will blindly overwrite the contents of that file during the
snapshot_blkdev monitor command, and we don't like a default of
data loss by default.  But VDSM has a scenario where NFS permissions
are intentionally set so that the destination file can only be
created by the management machine, and not the machine where the
guest is running, so that libvirt will necessarily see the destination
file already existing; adding a flag will allow VDSM to force the file
reuse without libvirt complaining of possible data loss.

https://bugzilla.redhat.com/show_bug.cgi?id=767104

* include/libvirt/libvirt.h.in (virDomainSnapshotCreateFlags): Add
VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.  Add
note about partial failure.
* tools/virsh.c (cmdSnapshotCreate, cmdSnapshotCreateAs): Add new
flag.
* tools/virsh.pod (snapshot-create, snapshot-create-as): Document
it.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiskPrepare)
(qemuDomainSnapshotCreateXML): Implement the new flag.

It should be a copy-paste error, the result is programming will result in an
infinite loop again due to without iterating 'j' variable.

* src/qemu/qemu_driver.c: fix a typo on qemuDomainSetBlkioParameters.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=770520Signed-off-by: NAlex Jia <ajia@redhat.com>

In the past, generic SCSI commands issued from a guest to a virtio
disk were always passed through to the underlying disk by qemu, and
the kernel would also pass them on.

As a result of CVE-2011-4127 (see:
http://seclists.org/oss-sec/2011/q4/536), qemu now honors its
scsi=on|off device option for virtio-blk-pci (which enables/disables
passthrough of generic SCSI commands), and the kernel will only allow
the commands for physical devices (not for partitions or logical
volumes). The default behavior of qemu is still to allow sending
generic SCSI commands to physical disks that are presented to a guest
as virtio-blk-pci devices, but libvirt prefers to disable those
commands in the standard virtio block devices, enabling it only when
specifically requested (hopefully indicating that the requester
understands what they're asking for). For this purpose, a new libvirt
disk device type (device='lun') has been created.

device='lun' is identical to the default device='disk', except that:

1) It is only allowed if bus='virtio', type='block', and the qemu
   version is "new enough" to support it ("new enough" == qemu 0.11 or
   better), otherwise the domain will fail to start and a
   CONFIG_UNSUPPORTED error will be logged).

2) The option "scsi=on" will be added to the -device arg to allow
   SG_IO commands (if device !='lun', "scsi=off" will be added to the
   -device arg so that SG_IO commands are specifically forbidden).

Guests which continue to use disk device='disk' (the default) will no
longer be able to use SG_IO commands on the disk; those that have
their disk device changed to device='lun' will still be able to use SG_IO
commands.

*docs/formatdomain.html.in - document the new device attribute value.
*docs/schemas/domaincommon.rng - allow it in the RNG
*tests/* - update the args of several existing tests to add scsi=off, and
 add one new test that will test scsi=on.
*src/conf/domain_conf.c - update domain XML parser and formatter

*src/qemu/qemu_(command|driver|hotplug).c - treat
 VIR_DOMAIN_DISK_DEVICE_LUN *almost* identically to
 VIR_DOMAIN_DISK_DEVICE_DISK, except as indicated above.

Note that no support for this new device value was added to any
hypervisor drivers other than qemu, because it's unclear what it might
mean (if anything) to those drivers.

This fixes https://bugzilla.redhat.com/show_bug.cgi?id=638633

Although scripts are not used by interfaces of type other than
"ethernet" in qemu, due to the fact that the parser stores the script
name in a union that is only valid when type is ethernet or bridge,
there is no way for anyone except the parser itself to catch the
problem of specifying an interface script for an inappropriate
interface type (by the time the parsed data gets back to the code that
called the parser, all evidence that a script was specified is
forgotten).

Since the parser itself should be agnostic to which type of interface
allows scripts (an example of why: a script specified for an interface
of type bridge is valid for xen domains, but not for qemu domains),
the solution here is to move the script out of the union(s) in the
DomainNetDef, always populate it when specified (regardless of
interface type), and let the driver decide whether or not it is
appropriate.

Currently the qemu, xen, libxml, and uml drivers recognize the script
parameter and do something with it (the uml driver only to report that
it isn't supported). Those drivers have been updated to log a
CONFIG_UNSUPPORTED error when a script is specified for an interface
type that's inappropriate for that particular hypervisor.

(NB: There was earlier discussion of solving this problem by adding a
VALIDATE flag to all libvirt APIs that accept XML, which would cause
the XML to be validated against the RNG files. One statement during
that discussion was that the RNG shouldn't contain hypervisor-specific
things, though, and a proper solution to this problem would require
that (again, because a script for an interface of type "bridge" is
accepted by xen, but not by qemu).

Commit ae523427 missed one pair of functions that could use
the helper routine.

* src/qemu/qemu_driver.c (qemuSetSchedulerParametersFlags)
(qemuGetSchedulerParametersFlags): Simplify.

When setting numa nodeset for a domain which has no nodeset set
before, libvirtd crashes by dereferencing the pointer to the old
nodemask which is null in that case.

Commit baade4d fixed a memory leak on failure, but in the process,
introduced a use-after-free on success, which can be triggered with:

1. set bandwidth with --live
2. query bandwidth
3. set bandwidth with --live

* src/qemu/qemu_driver.c (qemuDomainSetInterfaceParameters): Don't
free newBandwidth on success.
Reported by Hu Tao.

Typo has existed since API introduction in commit ee0d8c3b.

* src/qemu/qemu_driver.c (qemuDomainBlockStatsFlags): Use correct
name.

Most severe here is a latent (but currently untriggered) memory leak
if any hypervisor ever adds a string interface property; the
remainder are mainly cosmetic.

* include/libvirt/libvirt.h.in (VIR_DOMAIN_BANDWIDTH_*): Move
macros closer to interface that uses them, and document type.
* src/libvirt.c (virDomainSetInterfaceParameters)
(virDomainGetInterfaceParameters): Formatting tweaks.
* daemon/remote.c (remoteDispatchDomainGetInterfaceParameters):
Avoid memory leak.
* src/libvirt_public.syms (LIBVIRT_0.9.9): Sort lines.
* src/libvirt_private.syms (domain_conf.h): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSetInterfaceParameters): Fix
comments, break long lines.

Detected by Coverity. Leaks introduced in commit e8d6b293.
Signed-off-by: NAlex Jia <ajia@redhat.com>

Leak detected by Coverity, and introduced in commit 93ab5859.
Reported by Alex Jia.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters): Free
devices array on error.

* src/qemu/qemu_driver.c: implement the qemu driver support

https://bugzilla.redhat.com/show_bug.cgi?id=770520

We had two nested loops both trying to use 'i' as the iteration
variable, which can result in an infinite loop when the inner
loop interferes with the outer loop.  Introduced in commit 93ab5859.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters): Don't
reuse iteration variable across two loops.

In order to avoid situation where a USB device is
in use by two domains, we must keep a list of already
attached devices like we do for PCI.

The lifetime of the virDomainEventState object is tied to
the lifetime of the driver, which in stateless drivers is
tied to the lifetime of the virConnectPtr.

If we add & remove a timer when allocating/freeing the
virDomainEventState object, we can get a situation where
the timer still triggers once after virDomainEventState
has been freed. The timeout callback can't keep a ref
on the event state though, since that would be a circular
reference.

The trick is to only register the timer when a callback
is registered with the event state & remove the timer
when the callback is unregistered.

The demo for the bug is to run

  while true ; do date ; ../tools/virsh -q -c test:///default 'shutdown test; undefine test; dominfo test' ; done

prior to this fix, it will frequently hang and / or
crash, or corrupt memory

Currently all drivers using domain events need to provide a callback
for handling a timer to dispatch events in a clean stack. There is
no technical reason for dispatch to go via driver specific code. It
could trivially be dispatched directly from the domain event code,
thus removing tedious boilerplate code from all drivers

Also fix the libxl & xen drivers to pass 'true' when creating the
virDomainEventState, since they run inside the daemon & thus always
expect events to be present.

* src/conf/domain_event.c, src/conf/domain_event.h: Internalize
  dispatch of events from timer callback
* src/libxl/libxl_driver.c, src/lxc/lxc_driver.c,
  src/qemu/qemu_domain.c, src/qemu/qemu_driver.c,
  src/remote/remote_driver.c, src/test/test_driver.c,
  src/uml/uml_driver.c, src/vbox/vbox_tmpl.c,
  src/xen/xen_driver.c: Remove all timer dispatch functions

* src/libxl/libxl_driver.c, src/lxc/lxc_driver.c,
  src/qemu/qemu_driver.c, src/remote/remote_driver.c,
  src/test/test_driver.c, src/uml/uml_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Convert
  to threadsafe APIs

When registering a callback for a particular event some callers
need to know how many callbacks already exist for that event.
While it is possible to ask for a count, this is not free from
race conditions when threaded. Thus the API for registering
callbacks should return the count of callbacks. Also rename
virDomainEventStateDeregisterAny to virDomainEventStateDeregisterID

* src/conf/domain_event.c, src/conf/domain_event.h,
  src/libvirt_private.syms: Return count of callbacks when
  registering callbacks
* src/libxl/libxl_driver.c, src/libxl/libxl_driver.c,
  src/qemu/qemu_driver.c, src/remote/remote_driver.c,
  src/remote/remote_driver.c, src/uml/uml_driver.c,
  src/vbox/vbox_tmpl.c, src/xen/xen_driver.c: Update
  for change in APIs

If managed save fails at the right point in time, then the save
image can end up with 0 bytes in length (no valid header), and
our attempts in commit 55d88def to detect and skip invalid save
files missed this case.

* src/qemu/qemu_driver.c (qemuDomainSaveImageOpen): Also unlink
empty file as corrupt.  Reported by Dennis Householder.

This chunk of code below repeated in several functions, factor it into
a helper method virDomainLiveConfigHelperMethod to eliminate duplicated code
based on Eric and Adam's suggestion. I have tested it for all the
relevant APIs changed.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NLei Li <lilei@linux.vnet.ibm.com>