This patch adds support for the QEMU vhost-user feature to libvirt.
vhost-user enables the communication between a QEMU virtual machine
and other userspace process using the Virtio transport protocol.
It uses a char dev (e.g. Unix socket) for the control plane,
while the data plane based on shared memory.

The XML looks like:

<interface type='vhostuser'>
    <mac address='52:54:00:3b:83:1a'/>
    <source type='unix' path='/tmp/vhost.sock' mode='server'/>
    <model type='virtio'/>
</interface>
Signed-off-by: NMichele Paolino <m.paolino@virtualopensystems.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1119173 documents that
commit eaba79d2 was flawed in the implementation of the
VIR_DOMAIN_BLOCK_JOB_ABORT_ASYNC flag when it comes to completing
a blockcopy.  Basically, the qemu pivot action is async (the QMP
command returns immediately, but the user must wait for the
BLOCK_JOB_COMPLETE event to know that all I/O related to the job
has finally been flushed), but the libvirt command was documented
as synchronous by default.  As active block commit will also be
using this code, it is worth fixing now.

* src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Don't skip wait
loop after pivot.
Signed-off-by: NEric Blake <eblake@redhat.com>

Now that we've finally fixed all the violators, it's time to
enforce that any pointer to a const object is never freed (it
is aliasing some other memory, where the non-const original
should be freed instead).  Alas, the code still needs a normal
vs. Coverity version, but at least we are still guaranteeing
that the macro call evaluates its argument exactly once.

I verified that we still get the following compiler warnings,
which in turn halts the build thanks to -Werror on gcc (hmm,
gcc 4.8.3's placement of the ^ for ?: type mismatch is a bit
off, but that's not our problem):

    int oops1 = 0;
    VIR_FREE(oops1);
    const char *oops2 = NULL;
    VIR_FREE(oops2);
    struct blah { int dummy; } oops3;
    VIR_FREE(oops3);

util/virauthconfig.c:159:35: error: pointer/integer type mismatch in conditional expression [-Werror]
     VIR_FREE(oops1);
                                   ^
util/virauthconfig.c:161:5: error: passing argument 1 of 'virFree' discards 'const' qualifier from pointer target type [-Werror]
     VIR_FREE(oops2);
     ^
In file included from util/virauthconfig.c:28:0:
util/viralloc.h:79:6: note: expected 'void *' but argument is of type 'const void *'
 void virFree(void *ptrptr) ATTRIBUTE_NONNULL(1);
      ^
util/virauthconfig.c:163:35: error: type mismatch in conditional expression
     VIR_FREE(oops3);
                                   ^

* src/util/viralloc.h (VIR_FREE): No longer cast away const.
* src/xenapi/xenapi_utils.c (xenSessionFree): Work around bogus
header.
Signed-off-by: NEric Blake <eblake@redhat.com>

Add file in storagevolxml2xmlin and storagevolxml2xmlout, let
storagevolxml2xmltest and storagevolschematest cover 'nocow'.
Add test case to storagevolxml2argvtest to cover 'nocow'.
Signed-off-by: NChunyan Liu <cyliu@suse.com>

Add 'nocow' to storage volume xml so that user can have an option
to set NOCOW flag to the newly created volume. It's useful on btrfs
file system to enhance performance.

Btrfs has low performance when hosting VM images, even more when the guest
in those VM are also using btrfs as file system. One way to mitigate this
bad performance is to turn off COW attributes on VM files. Generally, there
are two ways to turn off COW on btrfs: a) by mounting fs with nodatacow,
then all newly created files will be NOCOW. b) per file. Add the NOCOW file
attribute. It could only be done to empty or new files.

This patch tries the second way, according to 'nocow' option, it could set
NOCOW flag per file:
for raw file images, handle 'nocow' in libvirt code; for non-raw file images,
pass 'nocow=on' option to qemu-img, and let qemu-img to handle that (requires
qemu-img version >= 2.1).
Signed-off-by: NChunyan Liu <cyliu@suse.com>

In many places we define a variable as a 'const char *' when in fact
we modify it just a few lines below. Or even free it. We should not do
that.

There's one exception though, in xenSessionFree() xenapi_utils.c. We
are freeing the xen_session structure which is defined in
xen/api/xen_common.h public header. The structure contains session_id
which is type of 'const char *' when in fact it should have been just
'char *'. So I'm leaving this unmodified, just noticing the fact in
comment.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

When the backing store of a volume wasn't accessible while updating the
volume definition the call would fail altogether. In cases where we
currently (incorrectly) treat remote backing stores as local one this
might lead to strange errors.

Ignore the opening errors until we figure out how to track proper volume
metadata.

Use the backing store parser to properly create the information about a
volume's backing store. Unfortunately as the storage driver isn't
prepared to allow volumes backed by networked filesystems add a
workaround that will avoid changing the XML output.

Move the processing of the backend metadata directly to the helper
instead of passing it through arguments to the function.

virStorageBackendFileSystemRefresh() used "cleanup" label just for error
exits and didn't meet libvirt's standard for braces in one case.

As we have a nested pointer for storing the backing store of a volume
there's no need to store it in a separate struct.

Assign the value we're comparing:
(val = func()) < 0
instead of assigning the comparison value:
(val = func() < 0)

Both were introduced along with the code,
the TLS tests by commit bd789dff in 0.9.4
net events by commit de87691f in 1.2.2.

Note that the event id type fix is a no-op:
vshNetworkEventIdTypeFromString can only return
-1 (failure) and the event is never used or
0 (the only possible event) and the value of 0 < 0 is still 0.

https://bugzilla.redhat.com/show_bug.cgi?id=1119592

Introduced by commit 62927dd8 v0.7.6.

Commit 20e01504 broke 'make rpm':

error: line 540: Unknown tag:     %elif 020 >= 12 || 0 >= 6

Apparently, even though shell has elif so that you can do a chain
of conditionals, the rpm spec file does not, and you have to nest
things instead.

* libvirt.spec.in: Convert %elif to proper nested %if.
Signed-off-by: NEric Blake <eblake@redhat.com>

Rework the apparmor lxc profile abstraction to mimic ubuntu's container-default.
This profile allows quite a lot, but strives to restrict access to
dangerous resources.

Removing the explicit authorizations to bash, systemd and cron files,
forces them to keep the lxc profile for all applications inside the
container. PUx permissions where leading to running systemd (and others
tasks) unconfined.

Put the generic files, network and capabilities restrictions directly
in the TEMPLATE.lxc: this way, users can restrict them on a per
container basis.

Rename linuxDomainInterfaceStats to virNetInterfaceStats in order
to allow adding platform specific implementations without
making consumer worrying about specific implementation to be used.

Also, rename util/virstatslinux.c to util/virstats.c so placing
other platform specific implementations into this file don't
look unexpected from the file name.

Code logic in libxlDomainAttachDeviceFlags and libxlDomainDetachDeviceFlags
is wrong with return value in error cases.

'ret' was being set to 0 if 'flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG' was
false. Then if something like virDomainDeviceDefParse() failed in the
VIR_DOMAIN_DEVICE_MODIFY_LIVE logic, the error would be reported but the
function would return success.
Signed-off-by: NChunyan Liu <cyliu@suse.com>

Add code to support attach/detaching a network device.
Signed-off-by: NChunyan Liu <cyliu@suse.com>

Missing HOSTDEV type in libxlDomainDetachDeviceConfig. Add it.
Signed-off-by: NChunyan Liu <cyliu@suse.com>

Use secured polkit on distros which provide it. However, RHEL-6 will
still allow for older polkit-0.93 rather than forcing polkit-0.96-5
which is not available in all RHEL-6 releases.

4cc1f1a0 introduced a crash when doing a
block copy as virStorageSourceInitChainElement was called on
"disk->mirror" that is still NULL at that point instead of "mirror"
which temporarily holds the mirror source struct until it's fully
initialized. This resulted into a crash as a NULL was dereferenced.

Reported by: Shanzi Yu <shyu@redhat.com>

Commit id '3ea661de' refactored the code to use the 'disk->src->path'
instead of getting the path from virDomainDiskGetSource().  The one
call to qemuOpenFile() didn't use the disk source path, rather it used
the path as passed from the caller (in this case 'vda') - this caused
a failure with the virt-test/tp-libvirt as follows:

$ virsh domblkinfo virt-tests-vm1 vda
error: cannot stat file '/home/virt-test/shared/data/images/jeos-20-64.qcow2': Bad file descriptor

$

While preparing to add a capability for active commit, I noticed
that the existing code was abusing int for boolean values.

* src/conf/capabilities.h (_virCapsGuestFeature, _virCapsHost)
(virCapabilitiesNew, virCapabilitiesAddGuestFeature): Improve
types.
* src/conf/capabilities.c (virCapabilitiesNew)
(virCapabilitiesAddGuestFeature): Adjust signature.
* src/bhyve/bhyve_capabilities.c (virBhyveCapsBuild): Update
clients.
* src/esx/esx_driver.c (esxCapsInit): Likewise.
* src/libxl/libxl_conf.c (libxlMakeCapabilities): Likewise.
* src/lxc/lxc_conf.c (virLXCDriverCapsInit): Likewise.
* src/openvz/openvz_conf.c (openvzCapsInit): Likewise.
* src/parallels/parallels_driver.c (parallelsBuildCapabilities):
Likewise.
* src/phyp/phyp_driver.c (phypCapsInit): Likewise.
* src/qemu/qemu_capabilities.c (virQEMUCapsInit)
(virQEMUCapsInitGuestFromBinary): Likewise.
* src/security/virt-aa-helper.c (get_definition): Likewise.
* src/test/test_driver.c (testBuildCapabilities): Likewise.
* src/uml/uml_conf.c (umlCapsInit): Likewise.
* src/vbox/vbox_tmpl.c (vboxCapsInit): Likewise.
* src/vmware/vmware_conf.c (vmwareCapsInit): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorBuildCapabilities):
Likewise.
* src/xenapi/xenapi_driver.c (getCapsObject): Likewise.
* tests/qemucaps2xmltest.c (testGetCaps): Likewise.
* tests/testutils.c (virTestGenericCapsInit): Likewise.
* tests/testutilslxc.c (testLXCCapsInit): Likewise.
* tests/testutilsqemu.c (testQemuCapsInit): Likewise.
* tests/testutilsxen.c (testXenCapsInit): Likewise.
* tests/vircaps2xmltest.c (buildVirCapabilities): Likewise.
* tests/vircapstest.c (buildNUMATopology): Likewise.
* tests/vmx2xmltest.c (testCapsInit): Likewise.
* tests/xml2vmxtest.c (testCapsInit): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Our documentation for features was rather sparse; this fleshes out
more of the details for other existing capabilities (and cost me
some time trawling git history).

* docs/formatcaps.html.in: Document it feature bits.
Signed-off-by: NEric Blake <eblake@redhat.com>

If the openvswitch service is stopped, and is followed by destroying a
VM, the openvswitch bridge translates into a state where it doesn't
recover the port configuration. While it successfully fetches data
from the internal DB, since the corresponding virtual interface does
not exists anymore the whole recovery process fails leaving restarted
VM with inability to connect to the bridge. The following set of
commands will trigger the problem:

virsh start vm
service openvswitch-switch stop
virsh destroy vm
service openvswitch-switch start
virsh start vm
Signed-off-by: NChunhe Li <lichunhe@huawei.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Resolve issue introduced by commit id '13adf1b2'

Instead of allocating the virSecurityLabelDef structure ourselves, we
can utilize virSecurityLabelDefNew which even sets the default values
for us.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1113860

We've always done that. Well, until 990e46c4. Point is, if we don't
format model, we may lose a domain on libvirtd restart. If the
seclabel is implicit however, we should skip it's formatting.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Snapshots and block-copy have a flag that forces qemu to re-use existing
file. Our docs weren't exactly clear on what the existing file should
contain for this to actually work.

Re-word the docs a bit to state that the file needs to be pre-created in
the desired format and the backing chain metadata needs to be set prior
to handing it over to qemu.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1084360

Libvirt generates external snapshot target file names for file backed
storage but not for block backed storage. Document the limitation.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1032363

Commit dae1568c converted the perms
member of the virStorageVolTarget struct into a pointer to make it
optional. But virStorageVolTargetDefFormat did not check perms for
NULL before dereferencing it.

Don't fail when there is nothing to do, as a tweak to the previous
patch regarding output of libvirt-UUID.files for LXC apparmor profiles
Signed-off-by: NEric Blake <eblake@redhat.com>

This was converted to a typedef in 5a2bd4c9 "conf: more enum
cleanups in "src/conf/domain_conf.h"" causing:
    libxl/libxl_conf.c: In function 'libxlDiskSetDiscard':
    libxl/libxl_conf.c:724:19: error: conversion to incomplete type
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>

In lxc, we could not use setmem command
with --config options.
This patch will add support for this.
Signed-off-by: NChen Hanxiao <chenhanxiao@cn.fujitsu.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1066894

With current code it's possible to have for instance:

virsh dumpxml mydomain | grep seclabel
  <seclabel type='dynamic' model='selinux' relabel='yes'/>
  <seclabel type='dynamic' model='selinux' relabel='yes'/>
  <seclabel type='dynamic' model='selinux' relabel='yes'/>
  <seclabel type='dynamic' model='selinux' relabel='yes'/>
  <seclabel type='dynamic' model='selinux' relabel='yes'/>

what doesn't make any sense. We should reject the XML in the config
parsing phase.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Similarly to the previous commit, boolean variables should not start
with 'no-' prefix.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

This negation in names of boolean variables is driving me insane. The
code is much more readable if we drop the 'no-' prefix. Well, at least
for me.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>