Since virDomainFree will call virObjectUnref anyway, let's just use that
directly so as to avoid the possibility that we inadvertently clear out
a pending error message when using the public API.
On some places in the libvirt code we have:
f(a,z)
instead of
f(a, z)
This trivial patch fixes couple of such occurrences.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Since not only systemd can do this (we'll be doing it as well few
patches later), change 'systemd' to 'caller' and fix LISTEN_FDS to
LISTEN_PID where applicable.
Signed-off-by: Martin Kletzander <mkletzan@redhat.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: Michal Privoznik <mprivozn@redhat.com>
In the future we might need to track state of individual images. Move
the readonly and shared flags to the virStorageSource struct so that we
can keep them in a per-image basis.
Replace:
if (virBufferError(&buf)) {
virBufferFreeAndReset(&buf);
virReportOOMError();
...
}
with:
if (virBufferCheckError(&buf) < 0)
...
This should not be a functional change (unless some callers
misused the virBuffer APIs - a different error would be reported
then)
When a domain was started without registration in sanlock, but libvirt
was restarted after that, most of the operations failed due to
contacting sanlock about that process. E.g. migration could not be
performed because the locks couldn't be released (or inquired before a
release).
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1088034
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Just move some code around for future patches to ease the review.
With this patch there is no need for drastic cleanup path later.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
The virnetsocket.c API is hardcoded to pass --timeout=30 to
any daemon it auto-starts. For inexplicable reasons the virtlockd
daemon did not implement the --timeout option, so it would
immediately exit on autostart with an error.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Make the lock plugin use virFileFindResource to find the
virtlockd daemon path, so that it executes the in-builddir
daemon if run from source tree.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=905282https://bugzilla.redhat.com/show_bug.cgi?id=967494
When lock failure is detected by sanlock, our sanlock_helper kill script
will try to restart (shutdown followed by start) the affected domain
when RESTART action is configured for it. While shutting down kills QEMU
and removes all its leases (which is what sanlock wants to happen),
trying to start it again just hangs because libvirt tries reacquire the
locks in the failed lock space. Hence, this action cannot be supported
by sanlock driver.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=905280https://bugzilla.redhat.com/show_bug.cgi?id=967493
Sanlock expects that the configured kill script either kills the PID on
lock failure or removes all locks the PID owns. If none of the two
options happen, sanlock will reboot the host. Although IGNORE action is
supposed to ignore the request to kill the PID or remove all leases,
it's certainly not designed to cause the host to be rebooted. That said,
IGNORE action is incompatible with sanlock and should be forbidden by
libvirt.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Part of a series of cleanups to use new accessor methods.
* src/locking/domain_lock.c (virDomainLockManagerAddDisk): Use
accessors.
Signed-off-by: Eric Blake <eblake@redhat.com>
A earlier commit changed the global log buffer so that it only
records messages that are explicitly requested via the log
filters setting. This removes the performance burden, and
improves the signal/noise ratio for messages in the global
buffer. At the same time though, it is somewhat pointless, since
all the recorded log messages are already going to be sent to an
explicit log output like syslog, stderr or the journal. The
global log buffer is thus just duplicating this data on stderr
upon crash.
The log_buffer_size config parameter is left in the augeas
lens to prevent breakage for users on upgrade. It is however
completely ignored hereafter.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit a1cbe4b5 added a check for spaces around assignments and this
patch extends it to checks for spaces around '=='. One exception is
virAssertCmpInt where comma after '==' is acceptable (since it is a
macro and '==' is its argument).
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=992980
This config tunable allows users to determine the maximum number of
accepted but yet not authenticated users.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Our current pidfile acquire APis (virPidFileAcquire) simply return -1 upon
failure to acquire a lock. This patch adds a parameter 'bool waitForLock'
which instructs the APIs if we want to make it block and wait for the lock
or not.
Convert the sanlock and lockd lock driver plugins over to use
the new virCryptoHashString APIs instead of having their own
duplicated code.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Libvirt uses a domain name to fill in owner_name in sanlock_options in
virLockManagerSanlockAcquire. Unfortunately, owner_name is limited to
SANLK_NAME_LEN characters (including trailing '\0'), which means domains
with longer names fail to start when sanlock is enabled. However, we can
truncate the name when setting owner_name as explained by sanlock's
author:
Setting sanlk_options or the owner_name is unnecessary, and has very
little to no benefit. If you do provide something in owner_name, it can
be anything, sanlock doesn't care or use it.
If you run the command "sanlock status", the output will display a list
of clients connected to the sanlock daemon. This client list is
displayed as "pid owner_name" if the client has provided an owner_name
via sanlk_options. This debugging output is the only usage of
owner_name, so its only benefit is to potentially provide a more human
friendly output for debugging purposes.
- Use $XDG_RUNTIME_DIR for re-exec state file when running unprivileged.
- argv[0] may not contain a full path to the binary, however it should
contain something that can be looked up in the PATH. Use execvp() to
do path lookup on re-exec.
- As per list discussion [1], ignore --daemon on re-exec.
[1] https://www.redhat.com/archives/libvir-list/2013-December/msg00514.html
Signed-off-by: Michael Chapman <mike@very.puzzling.org>
Some of our operation denied messages are outright stupid; for
example, if virIdentitySetAttr fails:
error: operation Identity attribute is already set forbidden for read only access
This patch fixes things to a saner:
error: operation forbidden: Identity attribute is already set
It also consolidates the most common usage pattern for operation
denied errors: read-only connections preventing a public API. In
this case, 'virsh -r -c test:///default destroy test' changes from:
error: operation virDomainDestroy forbidden for read only access
to:
error: operation forbidden: read only access prevents virDomainDestroy
Note that we were previously inconsistent on which APIs used
VIR_FROM_DOM (such as virDomainDestroy) vs. VIR_FROM_NONE (such as
virDomainPMSuspendForDuration). After this patch, all uses
consistently use VIR_FROM_NONE, on the grounds that it is unlikely
that a caller learning that a call is denied can do anything in
particular with extra knowledge which error domain the call belongs
to (similar to what we did in commit baa7244).
* src/util/virerror.c (virErrorMsg): Rework OPERATION_DENIED error
message.
* src/internal.h (virCheckReadOnlyGoto): New macro.
* src/util/virerror.h (virReportRestrictedError): New macro.
* src/libvirt-lxc.c: Use new macros.
* src/libvirt-qemu.c: Likewise.
* src/libvirt.c: Likewise.
* src/locking/lock_daemon.c (virLockDaemonClientNew): Likewise.
Signed-off-by: Eric Blake <eblake@redhat.com>
SIGHUP is commonly used to instruct a daemon to reload its config. For
now we should handle it in virtlockd just like SIGUSR1, rather than
having it kill the process.
Signed-off-by: Michael Chapman <mike@very.puzzling.org>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
- Use SIGUSR1, not SIGHUP, on reload. At present, virtlockd only
responds to the former.
- Fix PID file for virtlockd.
- Do not start virtlockd in any runlevels by default. It needs to be
explicitly selected in libvirt's qemu.conf anyway, so there is no
need to have it running on all systems regardless.
- Fix chkconfig priorities to ensure virtlockd is started before
libvirtd is started, and stopped after libvirtd is stopped.
- Add "Should-Start: virtlockd" to the libvirtd initscript's LSB header,
for the same reason.
- Add "Default-Stop" to both libvirtd and virtlockd initscripts. LSB
does not guarantee that this defaults to the inverse of
"Default-Start".
Signed-off-by: Michael Chapman <mike@very.puzzling.org>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
- Pass VIRTLOCKD_ARGS through to virtlockd.
- Use SIGUSR1, not SIGHUP, in ExecReload. At present, virtlockd only
responds to the former.
- Have "systemctl enable virtlockd.service" enable virtlockd.socket,
rather than throw an error.
- Make virtlockd.socket wanted by sockets.target, rather than
multi-user.target. This is consistent with other socket units in
Fedora, and it ensures that the socket is available before libvirtd is
started.
Signed-off-by: Michael Chapman <mike@very.puzzling.org>
Most of the usage of getuid()/getgid() is in cases where we are
considering what privileges we have. As such the code should be
using the effective IDs, not real IDs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Unconditional use of getenv is not secure in setuid env.
While not all libvirt code runs in a setuid env (since
much of it only exists inside libvirtd) this is not always
clear to developers. So make all the code paranoid, even
if it only ever runs inside libvirtd.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Each new VM requires a new connection from libvirtd to virtlockd.
The default max clients limit in virtlockd of 20 is thus woefully
insufficient. virtlockd sockets are only accessible to matching
users, so there is no security need for such a tight limit. Make
it configurable and default to 1024.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virtlockd/libvirtd daemons had listed '?' as the short option
for --help. getopt_long uses '?' for any unknown option. We want
to be able to distinguish unknown options (which use EXIT_FAILURE)
from correct usage of help (which should use EXIT_SUCCESS). Thus
we should use 'h' as a short option for --help. Also add this to
the man page docs
The virtlockd/libvirtd daemons did not list any short option
for the --version arg. Add -V as a valid short option, since
-v is already used for --verbose.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virtlockd daemon supports an /etc/libvirt/virtlockd.conf
config file, but we never installed a default config, nor
created any augeas scripts. This change addresses that omission.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This configuration knob lets user to set the length of queue of
connection requests waiting to be accept()-ed by the daemon. IOW, it
just controls the @backlog passed to listen:
int listen(int sockfd, int backlog);
Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce annotations to all RPC messages to declare what
access control checks are required. There are two new
annotations defined:
@acl: <object>:<permission>
@acl: <object>:<permission>:<flagname>
Declare the access control requirements for the API. May be repeated
multiple times, if multiple rules are required.
<object> is one of 'connect', 'domain', 'network', 'storagepool',
'interface', 'nodedev', 'secret'.
<permission> is one of the permissions in access/viraccessperm.h
<flagname> indicates the rule only applies if the named flag
is set in the API call
@aclfilter: <object>:<permission>
Declare an access control filter that will be applied to a list
of objects being returned by an API. This allows the returned
list to be filtered to only show those the user has permissions
against
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Since PIDs can be reused, polkit prefers to be given
a (PID,start time) pair. If given a PID on its own,
it will attempt to lookup the start time in /proc/pid/stat,
though this is subject to races.
It is safer if the client app resolves the PID start
time itself, because as long as the app has the client
socket open, the client PID won't be reused.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
A 'uri' parameter was added for the benefit of sanlock. This
causes a warning in the lockd driver though
2013-05-03 13:20:35.347+0000: 28403: error : virLockManagerLockDaemonNew:482 : internal error Unexpected parameter uri for object
Ignore this parameter, since lockd does not require it and it
is harmless if not used.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The lockd plugin for the lock manager was not correctly
handling the release of resource locks. This meant that
during migration, or when pausing a VM, the locks would
not get released. This in turn made it impossible to
resume the domain, or finish migration
The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.
Currently the RPC protocol files can contain annotations after
the protocol enum eg
REMOTE_PROC_DOMAIN_SNAPSHOT_LIST_CHILDREN_NAMES = 247, /* autogen autogen priority:high */
This is not very extensible as the number of annotations grows.
Change it to use
/**
* @generate: both
* @priority: high
*/
REMOTE_PROC_DOMAIN_SNAPSHOT_LIST_CHILDREN_NAMES = 247,
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
In virLockSpaceProtocolDispatchNew() the returned value of lockspace from
virLockDaemonFindLockSpace() is overwritten by the virLockSpaceNew() return.
Coverity complains that it's unused.
In virLockSpaceProtocolDispatchCreateLockSpace() lockspace is also overwritten
in a similar manner resulting in the same Coverity message.
POSIX does not guarantee whether uid_t and gid_t are signed or
unsigned, nor does it guarantee whether they are smaller, same
size, or larger than int (or even the same size as one another).
Therefore, it is possible to have platforms where '(uid_t)-1==-1'
is false or where 'uid = gid = -1' sets uid to the wrong value,
thanks to integer promotion rules. The only portable way to use
the placeholder value of these two types is to always use a cast.
Thankfully, the issue is mostly theoretical - sanlock only
compiles on Linux for now, and on Linux, these types do not
suffer from strange promotion problems.
* src/locking/lock_driver_sanlock.c
(virLockManagerSanlockSetupLockspace, virLockManagerSanlockInit)
(virLockManagerSanlockCreateLease): Cast -1 to proper type before
comparing with uid_t or gid_t.
virtlockd.service could be installed to a configurable root,
but virtlockd.socket was hardcoded to installation into a
distro.
* src/Makefile.am (virtlockd.service, virtlockd.socket): Drop
unused substitutions.
* src/locking/virtlockd.socket.in (ListenStream): Don't hard-code
/var.
We had several different styles of .in conversion in our Makefiles:
ALLCAPS, @ALLCAPS@, @lower@, ::lower::
Canonicalize on one form, to make it easier to copy and paste
between .in files.
Also, we were using some non-portable sed constructs: \@ is an
undefined escape sequence (it happens to be @ itself in GNU sed,
but POSIX allows it to mean something else), as well as risky
behavior (failure to consistently quote things means a space
in $(sysconfdir) could throw things off; also, Autoconf recommends
using | rather than , or ! in the s||| operator, because | has to
be quoted in shell and is therefore less likely to appear in file
names than , or !).
Fix all of these uses to follow the same syntax.
* daemon/libvirtd.8.in: Switch to @var@.
* tools/virt-xml-validate.in: Likewise.
* tools/virt-pki-validate.in: Likewise.
* src/locking/virtlockd.init.in: Likewise.
* daemon/Makefile.am: Prefer | over ! in sed.
(libvirtd.8): Prefer consistent substitution.
(libvirtd.init, libvirtd.service): Avoid non-portable sed.
* tools/Makefile.am (libvirt-guests.sh, libvirt-guests.init)
(libvirt-guests.service): Likewise.
(virt-xml-validate, virt-pki-validate, virt-sanlock-cleanup):
Prefer consistent capitalization.
* src/Makefile.am (virtlockd.init, virtlockd.service)
(virtlockd.socket): Prefer consistent substitution.
Since sanlock doesn't run under root:root, we have chown()'ed the
__LIBVIRT__DISKS__ lease file to the user:group defined in the
sanlock config. However, when writing the patch I've forgot about
lease files for each disk (this is the
/var/lib/libvirt/sanlock/<md5>) file.
Currently, if sanlock is already registering a lockspace other
libvirtd instances (from other hosts) obtain -EINPROGRESS. On
sufficiently new sanlock, sanlock_inq_lockspace() is called,
which suspend execution until lockspace state is changed. With
current libvirt implementation, we fail to retry adding the
lockspace again but continue in error path. Therefore we produce
meaningless error message:
virLockManagerSanlockSetupLockspace:363 : Unable to add lockspace
/var/lib/libvirt/sanlock/__LIBVIRT__DISKS__: Success
qemudLoadDriverConfig:558 : Failed to load lock manager sanlock
We should try to re-add the lockspace after its state change to
be sure it was added successfully. In fact, with sufficiently new
sanlock we can just avoid dummy usleep() which is used if there's
no inquire API.
The default lockd driver behavour is to acquire leases
directly on the disk files. This introduces an alternative
mode, where leases are acquire indirectly on a file that
is based on a SHA256 hash of the disk filename.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This adds a 'lockd' lock driver which is just a client which
talks to the lockd daemon to perform all locking. This will
be the default lock driver for any hypervisor which needs one.
* src/Makefile.am: Add lockd.so plugin
* src/locking/lock_driver_lockd.c: Lockd driver impl
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virtlockd daemon maintains file locks on behalf of libvirtd
and any VMs it is running. These file locks must be held for as
long as any VM is running. If virtlockd itself ever quits, then
it is expected that a node would be fenced/rebooted. Thus to
allow for software upgrads on live systemd, virtlockd needs the
ability to re-exec() itself.
Upon receipt of SIGUSR1, virtlockd will save its current live
state out to a file /var/run/virtlockd-restart-exec.json
It then re-exec()'s itself with exactly the same argv as it
originally had, and loads the state file, reconstructing any
objects as appropriate.
The state file contains information about all locks held and
all network services and clients currently active. An example
state document is
{
"server": {
"min_workers": 1,
"max_workers": 20,
"priority_workers": 0,
"max_clients": 20,
"keepaliveInterval": 4294967295,
"keepaliveCount": 0,
"keepaliveRequired": false,
"services": [
{
"auth": 0,
"readonly": false,
"nrequests_client_max": 1,
"socks": [
{
"fd": 6,
"errfd": -1,
"pid": 0,
"isClient": false
}
]
}
],
"clients": [
{
"auth": 0,
"readonly": false,
"nrequests_max": 1,
"sock": {
"fd": 9,
"errfd": -1,
"pid": 0,
"isClient": true
},
"privateData": {
"restricted": true,
"ownerPid": 1722,
"ownerId": 6,
"ownerName": "f18x86_64",
"ownerUUID": "97586ba9-df27-9459-c806-f016c8bbd224"
}
},
{
"auth": 0,
"readonly": false,
"nrequests_max": 1,
"sock": {
"fd": 10,
"errfd": -1,
"pid": 0,
"isClient": true
},
"privateData": {
"restricted": true,
"ownerPid": 1784,
"ownerId": 7,
"ownerName": "f16x86_64",
"ownerUUID": "7b8e5e42-b875-61e9-b981-91ad8fa46979"
}
}
]
},
"defaultLockspace": {
"resources": [
{
"name": "/var/lib/libvirt/images/f16x86_64.raw",
"path": "/var/lib/libvirt/images/f16x86_64.raw",
"fd": 14,
"lockHeld": true,
"flags": 0,
"owners": [
1784
]
},
{
"name": "/var/lib/libvirt/images/shared.img",
"path": "/var/lib/libvirt/images/shared.img",
"fd": 12,
"lockHeld": true,
"flags": 1,
"owners": [
1722,
1784
]
},
{
"name": "/var/lib/libvirt/images/f18x86_64.img",
"path": "/var/lib/libvirt/images/f18x86_64.img",
"fd": 11,
"lockHeld": true,
"flags": 0,
"owners": [
1722
]
}
]
},
"lockspaces": [
],
"magic": "30199"
}
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This enhancement virtlockd so that it can receive a pre-opened
UNIX domain socket from systemd at launch time, and adds the
systemd service/socket unit files
* daemon/libvirtd.service.in: Require virtlockd to be running
* libvirt.spec.in: Add virtlockd systemd files
* src/Makefile.am: Install systemd files
* src/locking/lock_daemon.c: Support socket activation
* src/locking/virtlockd.service.in, src/locking/virtlockd.socket.in:
systemd unit files
* src/rpc/virnetserverservice.c, src/rpc/virnetserverservice.h:
Add virNetServerServiceNewFD() method
* src/rpc/virnetsocket.c, src/rpc/virnetsocket.h: Add virNetSocketNewListenFD
method
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce a lock_daemon_dispatch.c file which implements the
server side dispatcher the RPC APIs previously defined in the
lock protocol.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virtlockd daemon will be responsible for managing locks
on virtual machines. Communication will be via the standard
RPC infrastructure. This provides the XDR protocol definition
* src/locking/lock_protocol.x: Wire protocol for virtlockd
* src/Makefile.am: Include lock_protocol.[ch] in virtlockd
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virtlockd daemon will maintain locks on behalf of libvirtd.
There are two reasons for it to be separate
- Avoid risk of other libvirtd threads accidentally
releasing fcntl() locks by opening + closing a file
that is locked
- Ensure locks can be preserved across libvirtd restarts.
virtlockd will need to be able to re-exec itself while
maintaining locks. This is simpler to achieve if its
sole job is maintaining locks
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Refactor virLockManagerPluginNew() so that the caller does
not need to pass in the config file path itself - just the
config directory and driver name.
Fix QEMU to actually pass in a config file when creating the
default lock manager plugin, rather than NULL.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
It may take some time for sanlock to add a lockspace. And if user
restart libvirtd service meanwhile, the fresh daemon can fail adding
the same lockspace with EINPROGRESS. Recent sanlock has
sanlock_inq_lockspace() function which should block until lockspace
changes state. If we are building against older sanlock we should
retry a few times before claiming an error. This issue can be easily
reproduced:
for i in {1..1000} ; do echo $i; service libvirtd restart; sleep 2; done
20
Stopping libvirtd daemon: [FAILED]
Starting libvirtd daemon: [ OK ]
21
Stopping libvirtd daemon: [ OK ]
Starting libvirtd daemon: [ OK ]
22
Stopping libvirtd daemon: [ OK ]
Starting libvirtd daemon: [ OK ]
error : virLockManagerSanlockSetupLockspace:334 : Unable to add
lockspace /var/lib/libvirt/sanlock/__LIBVIRT__DISKS__: Operation now in
progress
The libvirt coding standard is to use 'function(...args...)'
instead of 'function (...args...)'. A non-trivial number of
places did not follow this rule and are fixed in this patch.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
libvirt started using sanlock_killpath to implement on_lockfailure
action. Since sanlock_killpath was introduced in sanlock 2.4, libvirt
fails to build with older sanlock.
While the changes to sanlock driver should be stable, the actual
implementation of sanlock_helper is supposed to be replaced in the
future. However, before we can implement a better sanlock_helper, we
need an administrative interface to libvirtd so that the helper can just
pass a "leases lost" event to the particular libvirt driver and
everything else will be taken care of internally. This approach will
also allow libvirt to pass such event to applications and use
appropriate reasons when changing domain states.
The temporary implementation handles all actions directly by calling
appropriate libvirt APIs (which among other things means that it needs
to know the credentials required to connect to libvirtd).
