Busy enterprise workloads hosted on large sized VM's tend to dirty
memory faster than the transfer rate achieved via live guest migration.
Despite some good recent improvements (& using dedicated 10Gig NICs
between hosts) the live migration may NOT converge.

Recently support was added in qemu (version 1.6) to allow a user to
choose if they wish to force convergence of their migration via a
new migration capability : "auto-converge". This feature allows for qemu
to auto-detect lack of convergence and trigger a throttle-down of the
VCPUs.

This patch includes the libvirt support needed to trigger this
feature. (Testing is in progress)
Signed-off-by: NChegu Vinod <chegu_vinod@hp.com>
Signed-off-by: NJiri Denemark <jdenemar@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: NDaniel 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: NMartin Kletzander <mkletzan@redhat.com>

Auditing all callers of virCommandRun and virCommandWait that
passed a non-NULL pointer for exit status turned up some
interesting observations.  Many callers were merely passing
a pointer to avoid the overall command dying, but without
caring what the exit status was - but these callers would
be better off treating a child death by signal as an abnormal
exit.  Other callers were actually acting on the status, but
not all of them remembered to filter by WIFEXITED and convert
with WEXITSTATUS; depending on the platform, this can result
in a status being reported as 256 times too big.  And among
those that correctly parse the output, it gets rather verbose.
Finally, there were the callers that explicitly checked that
the status was 0, and gave their own message, but with fewer
details than what virCommand gives for free.

So the best idea is to move the complexity out of callers and
into virCommand - by default, we return the actual exit status
already cleaned through WEXITSTATUS and treat signals as a
failed command; but the few callers that care can ask for raw
status and act on it themselves.

* src/util/vircommand.h (virCommandRawStatus): New prototype.
* src/libvirt_private.syms (util/command.h): Export it.
* docs/internals/command.html.in: Document it.
* src/util/vircommand.c (virCommandRawStatus): New function.
(virCommandWait): Adjust semantics.
* tests/commandtest.c (test1): Test it.
* daemon/remote.c (remoteDispatchAuthPolkit): Adjust callers.
* src/access/viraccessdriverpolkit.c (virAccessDriverPolkitCheck):
Likewise.
* src/fdstream.c (virFDStreamCloseInt): Likewise.
* src/lxc/lxc_process.c (virLXCProcessStart): Likewise.
* src/qemu/qemu_command.c (qemuCreateInBridgePortWithHelper):
Likewise.
* src/xen/xen_driver.c (xenUnifiedXendProbe): Simplify.
* tests/reconnect.c (mymain): Likewise.
* tests/statstest.c (mymain): Likewise.
* src/bhyve/bhyve_process.c (virBhyveProcessStart)
(virBhyveProcessStop): Don't overwrite virCommand error.
* src/libvirt.c (virConnectAuthGainPolkit): Likewise.
* src/openvz/openvz_driver.c (openvzDomainGetBarrierLimit)
(openvzDomainSetBarrierLimit): Likewise.
* src/util/virebtables.c (virEbTablesOnceInit): Likewise.
* src/util/viriptables.c (virIpTablesOnceInit): Likewise.
* src/util/virnetdevveth.c (virNetDevVethCreate): Fix debug
message.
* src/qemu/qemu_capabilities.c (virQEMUCapsInitQMP): Add comment.
* src/storage/storage_backend_iscsi.c
(virStorageBackendISCSINodeUpdate): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

And provide domain summary stat in that case, for lxc backend.
Use case is a container inheriting all devices from the host,
e.g. when doing application containerization.

At this point it has a limited functionality and is highly
experimental. Supported domain operations are:

  * define
  * start
  * destroy
  * dumpxml
  * dominfo

It's only possible to have only one disk device and only one
network, which should be of type bridge.

Remove double "is".
Consistent spelling of all-uppercase I/O.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

Currently the qemuDomainGetBlockInfo will return allocation == physical
for most backing stores. For a qcow2 block backed device it's possible
to return the highest lv extent allocated from qemu for an active guest.
That is a value where allocation != physical and one would hope be less.
However, if the guest is not running, then the code falls back to returning
allocation == physical. This turns out to be problematic for rhev which
monitors the size of the backing store. During a migration, before the
VM has been started on the target and while it is deemed inactive on the
source, there's a small window of time where the allocation is returned
as physical triggering the code to extend the file unnecessarily.

Since rhev uses transient domains and this is edge condition for a transient
domain, rather than returning good status and allocation == physical when
this "window of opportunity" exists, this patch will check for a transient
(or non persistent) domain and return a failure to the caller rather than
returning the defaults. For a persistent domain, the defaults will be
returned. The description for the virDomainGetBlockInfo has been updated
to describe the phenomena.

I noticed that we allow virDomainGetVcpusFlags even for read-only
connections, but that with a flag, it can require guest agent
interaction.  It is feasible that a malicious guest could
intentionally abuse the replies it sends over the guest agent
connection to possibly trigger a bug in libvirt's JSON parser,
or withhold an answer so as to prevent the use of the agent
in a later command such as a shutdown request.  Although we
don't know of any such exploits now (and therefore don't mind
posting this patch publicly without trying to get a CVE assigned),
it is better to err on the side of caution and explicitly require
full access to any domain where the API requires guest interaction
to operate correctly.

I audited all commands that are marked as conditionally using a
guest agent.  Note that at least virDomainFSTrim is documented
as needing a guest agent, but that such use is unconditional
depending on the hypervisor (so the existing domain:fs_trim ACL
should be sufficient there, rather than also requirng domain:write).
But when designing future APIs, such as the plans for obtaining
a domain's IP addresses, we should copy the approach of this patch
in making interaction with the guest be specified via a flag, and
use that flag to also require stricter access checks.

* src/libvirt.c (virDomainGetVcpusFlags): Forbid guest interaction
on read-only connection.
(virDomainShutdownFlags, virDomainReboot): Improve docs on agent
interaction.
* src/remote/remote_protocol.x
(REMOTE_PROC_DOMAIN_SNAPSHOT_CREATE_XML)
(REMOTE_PROC_DOMAIN_SET_VCPUS_FLAGS)
(REMOTE_PROC_DOMAIN_GET_VCPUS_FLAGS, REMOTE_PROC_DOMAIN_REBOOT)
(REMOTE_PROC_DOMAIN_SHUTDOWN_FLAGS): Require domain:write for any
conditional use of a guest agent.
* src/xen/xen_driver.c: Fix clients.
* src/libxl/libxl_driver.c: Likewise.
* src/uml/uml_driver.c: Likewise.
* src/qemu/qemu_driver.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Finish the cleanup of libvirt.c; all uses of virLib*Error have
now been converted to more canonical conventions.

* src/libvirt.c: Use virReportError in remaining errors.
(virLibConnError, virLibDomainError): Delete unused macros.
* cfg.mk (msg_gen_function): Drop unused names.
Signed-off-by: NEric Blake <eblake@redhat.com>

We had a lot of repetition of errors that would occur if we
ever register too many drivers; this is unlikely to occur
unless we start adding a lot of new hypervisor modules, but
if it does occur, it's better to have uniform handling of the
situation, so that a one-line change is all that would be
needed if we decide that an internal error is not the best.

* src/libvirt.c (virDriverCheckTabMaxReturn): New define.
(virRegister*Driver): Use it for less code duplication.
Signed-off-by: NEric Blake <eblake@redhat.com>

The choice of error message and category was not consistent
in the migration code; furthermore, the use of virLibConnError
is no longer necessary now that we have a generic virReportError.

* src/qemu/qemu_migration.c (virDomainMigrate*): Prefer
virReportError over virLibConnError.
Signed-off-by: NEric Blake <eblake@redhat.com>

While auditing the error reporting, I noticed that migration
had some issues.  Some of the static helper functions tried
to call virDispatchError(), even though their caller will also
report the error.  Also, if a migration is cancelled early
because a uri was not set, we did not guarantee that the finish
stage would not overwrite the first error message.

* src/qemu/qemu_migration.c (doPeer2PeerMigrate2)
(doPeer2PeerMigrate3): Preserve first error when cancelling.
* src/libvirt.c (virDomainMigrateVersion3Full): Likewise.
(virDomainMigrateVersion1, virDomainMigrateVersion2)
(virDomainMigrateDirect): Avoid redundant error dispatch.
(virDomainMigrateFinish2, virDomainMigrateFinish3)
(virDomainMigrateFinish3Params): Don't report error on cleanup
path.
Signed-off-by: NEric Blake <eblake@redhat.com>

Several APIs clear out a user input buffer before attempting to
populate it; but in a few cases we missed this memset if we
detect a reason for an early exit.  Note that these APIs
check for non-NULL arguments, and exit early with an error
message when NULL is passed in; which means that we must be
careful to avoid a NULL deref in order to get to that error
message.  Also, we were inconsistent on the use of
sizeof(virType) vs. sizeof(expression); the latter is more
robust if we ever change the type of the expression (although
such action is unlikely since these types are part of our
public API).

* src/libvirt.c (virDomainGetInfo, virDomainGetBlockInfo)
(virStoragePoolGetInfo, virStorageVolGetInfo)
(virDomainGetJobInfo, virDomainGetBlockJobInfo): Move memset
before any returns.
Signed-off-by: NEric Blake <eblake@redhat.com>

Our fixes for CVE-2013-4400 were so effective at "fixing" bugs
in virt-login-shell that we ended up fixing it into a useless
do-nothing program.

Commit 3e2f27e1 picked the name LIBVIRT_SETUID_RPC_CLIENT for
the witness macro when we are doing secure compilation.  But
commit 9cd6a57d checked whether the name IN_VIRT_LOGIN_SHELL,
from an earlier version of the patch series, was defined; with
the net result that virt-login-shell invariably detected that
it was setuid and failed virInitialize.

Commit b7fcc799 closed all fds larger than stderr, but in the
wrong place.  Looking at the larger context, we mistakenly did
the close in between obtaining the set of namespace fds, then
actually using those fds to switch namespace, which means that
virt-login-shell will ALWAYS fail.

This is the minimal patch to fix the regressions, although
further patches are also worth having to clean up poor
semantics of the resulting program (for example, it is rude to
not pass on the exit status of the wrapped program back to the
invoking shell).

* tools/virt-login-shell.c (main): Don't close fds until after
namespace swap.
* src/libvirt.c (virGlobalInit): Use correct macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

The existing check of domain snapshots validated that they
point to a domain, but did not validate that the domain
points to a connection, even though any errors blindly assume
the connection is valid.  On the other hand, as mentioned in
commit 6e130ddc, any valid domain is already tied to a valid
connection, and VIR_IS_SNAPSHOT vs. VIR_IS_DOMAIN_SNAPSHOT
makes no real difference; it's best to just validate the chain
of all three.  For consistency with previous patches, continue
the trend of using a common macro.  For now, we don't need
virCheckDomainSnapshotGoto().

* src/datatypes.h (virCheckDomainSnapshotReturn): New macro.
(VIR_IS_SNAPSHOT, VIR_IS_DOMAIN_SNAPSHOT):
Drop unused macros.
* src/libvirt.c: Use macro throughout.
(virLibDomainSnapshotError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

While all errors related to invalid nwfilters appeared to be
consistent, we might as well continue the trend of using a
common macro.  As in commit 6e130ddc, the difference between
VIR_IS_NWFILTER and VIR_IS_CONNECTED_NWFILTER is moot, since
reference counting means any valid nwfilter is also tied to
a valid connection.  For now, we don't need virCheckNWFilterGoto().

* src/datatypes.h (virCheckNWFilterReturn): New macro.
(VIR_IS_NWFILTER, VIR_IS_CONNECTED_NWFILTER): Drop unused macros.
* src/libvirt.c: Use macro throughout.
(virLibNWFilterError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

For streams validation, we weren't consistent on whether to
use VIR_FROM_NONE or VIR_FROM_STREAMS.  Furthermore, in many
API, we want to ensure that a stream is tied to the same
connection as the other object we are operating on; while
other API failed to validate the stream at all.  And the
difference between VIR_IS_STREAM and VIR_IS_CONNECTED_STREAM
is moot; as in commit 6e130ddc, we know that reference
counting means a valid stream will always be tied to a valid
connection.  Similar to previous patches, use a common macro
to make it nicer.

* src/datatypes.h (virCheckStreamReturn, virCheckStreamGoto):
New macros.
(VIR_IS_STREAM, VIR_IS_CONNECTED_STREAM): Drop unused macros.
* src/libvirt.c: Use macro throughout.
(virLibStreamError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

While all errors related to invalid secrets appeared to be
consistent, we might as well continue the trend of using a
common macro.  Just as in commit 6e130ddc, the difference
between VIR_IS_SECRET and VIR_IS_CONNECTED_SECRET is moot
(due to reference counting, any valid secret must be tied to
a valid domain).  For now, we don't need virCheckSecretGoto().

* src/datatypes.h (virCheckSecretReturn): New macro.
(VIR_IS_SECRET, VIR_IS_CONNECTED_SECRET): Drop unused macros.
* src/libvirt.c: Use macro throughout.
(virLibSecretError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

While all errors related to invalid node device appeared to be
consistent, we might as well continue the trend of using a
common macro.  For now, we don't need virCheckNodeDeviceGoto().

* src/datatypes.h (virCheckNodeDeviceReturn): New macro.
(VIR_IS_NODE_DEVICE, VIR_IS_CONNECTED_NODE_DEVICE): Drop
unused macros.
* src/libvirt.c: Use macro throughout.
(virLibNodeDeviceError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

For storage volume validation, we weren't consistent on
whether to use VIR_FROM_NONE or VIR_FROM_STORAGE.  Similar
to previous patches, use a common macro to make it nicer.
Furthermore, just as in commit 6e130ddc, the difference
between VIR_IS_STORAGE_VOL and VIR_IS_CONNECTED_STORAGE_VOL
is moot (due to reference counting, any valid volume must
be tied to a valid connection).

virStorageVolCreateXMLFrom allows cross-connection cloning,
where the error is reported against the connection of the
destination pool.

* src/datatypes.h (virCheckStorageVolReturn)
(virCheckStorageVolGoto): New macros.
(VIR_IS_STORAGE_VOL, VIR_IS_CONNECTED_STORAGE_VOL): Drop
unused macros.
* src/libvirt.c: Use macro throughout.
(virLibStorageVolError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

virStoragePoolBuild reported an invalid pool as if it were an
invalid network.  Likewise, we weren't consistent on whether to
use VIR_FROM_NONE or VIR_FROM_STORAGE.  Similar to previous
patches, use a common macro to make it nicer.  Furthermore, just
as in commit 6e130ddc, the difference between VIR_IS_STORAGE_POOL
and VIR_IS_CONNECTED_STORAGE_POOL is moot (due to reference
counting, any valid pool must be tied to a valid connection).
For now, we don't need virCheckStoragePoolGoto().

* src/datatypes.h (virCheckStoragePoolReturn): New macro.
(VIR_IS_STORAGE_POOL, VIR_IS_CONNECTED_STORAGE_POOL): Drop
unused macros.
* src/libvirt.c: Use macro throughout.
(virLibStoragePoolError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

When checking for a valid interface, we weren't consistent on
whether we reported as VIR_FROM_NONE or VIR_FROM_INTERFACE.
Similar to previous patches, use a common macro to make it nicer.
Furthermore, just as in commit 6e130ddc, the difference between
VIR_IS_INTERFACE and VIR_IS_CONNECTED_INTERFACE is moot (due to
reference counting, any valid interface must be tied to a valid
connection).  For now, we don't need virCheckInterfaceGoto().

* src/datatypes.h (virCheckInterfaceReturn): New macro.
(VIR_IS_INTERFACE, VIR_IS_CONNECTED_INTERFACE): Drop unused
macros.
* src/libvirt.c: Use macro throughout.
(virLibInterfaceError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

When checking for a valid network, we weren't consistent on
whether we reported an invalid network or a connection.  Similar
to previous patches such as commit 6e130ddc, the difference
between VIR_IS_NETWORK and VIR_IS_CONNECTED_NETWORK is moot (due
to reference counting, any valid network must be tied to a valid
connection).  Use a common macro to make the error reporting
for invalid networks nicer.

* src/datatypes.h (virCheckNetworkReturn, virCheckNetworkGoto): New
macros.
(VIR_IS_NETWORK, VIR_IS_CONNECTED_NETWORK): Drop unused macros.
* src/libvirt.c: Use macro throughout.
(virLibNetworkError): Drop unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

The function checks for @conn to be valid and locks its mutex. Then, it
checks if callee is unregistering the same callback that he registered
previously. If this fails an error is reported and  the control jumps to
'error' label. Here, if @conn has some errors (and it certainly does -
the one that's been just reported) the conn->mutex is locked again -
without any previous unlock:

  Thread 1 (Thread 0x7fb500ef1800 (LWP 18982)):
  #0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
  #1  0x00007fb4fd99ce56 in _L_lock_918 () from /lib64/libpthread.so.0
  #2  0x00007fb4fd99ccaa in __GI___pthread_mutex_lock (mutex=0x7fb50153b670) at pthread_mutex_lock.c:64
  #3  0x00007fb5007e574d in virMutexLock (m=m@entry=0x7fb50153b670) at util/virthreadpthread.c:85
  #4  0x00007fb5007b198e in virDispatchError (conn=conn@entry=0x7fb50153b5e0) at util/virerror.c:594
  #5  0x00007fb5008a3735 in virConnectUnregisterCloseCallback (conn=0x7fb50153b5e0, cb=cb@entry=0x7fb500f588e0 <vshCatchDisconnect>) at libvirt.c:21025
  #6  0x00007fb500f5d690 in vshReconnect (ctl=ctl@entry=0x7fffff60e710) at virsh.c:328
  #7  0x00007fb500f5dc50 in vshCommandRun (ctl=ctl@entry=0x7fffff60e710, cmd=0x7fb50152ca80) at virsh.c:1755
  #8  0x00007fb500f5861b in main (argc=<optimized out>, argv=<optimized out>) at virsh.c:3393

And since the conn's mutex is not recursive, the virDispatchError will
never ever lock it successfully.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

In datatype.c, virGetDomainSnapshot could result in the message:

error: invalid domain pointer in bad domain

Furthermore, while there are a few functions in libvirt.c that
only care about a virDomainPtr without regards to the connection
(such as virDomainGetName), most functions also require a valid
connection.  Yet several functions were blindly dereferencing
the conn member without checking it for validity first (such as
virDomainOpenConsole).  Rather than try and correct all usage
of VIR_IS_DOMAIN vs. VIR_IS_CONNECTED_DOMAIN, it is easier to
just blindly require that a valid domain object always has a
valid connection object (which should be true anyways, since
every domain object holds a reference to its connection, so the
connection will not be closed until all domain objects have
also been closed to release their reference).

After this patch, all places that validate a domain consistently
report:

error: invalid domain pointer in someFunc

* src/datatypes.h (virCheckDomainReturn, virCheckDomainGoto): New
macros.
* src/datatypes.c (virGetDomainSnapshot): Use new macro.
(virLibConnError): Delete unused macro.
Signed-off-by: NEric Blake <eblake@redhat.com>

Ever since their introduction (commit 1509b802 in v0.5.0 for
virConnectDomainEventRegister, commit 44457238 in v0.8.0 for
virConnectDomainEventDeregisterAny), the event deregistration
functions have been documented as returning 0 on success;
likewise for older registration (only the newer RegisterAny
must return a non-zero callbackID).  And now that we are
adding virConnectNetworkEventDeregisterAny for v1.2.1, it
should have the same semantics.

Fortunately, all of the stateful drivers have been obeying
the docs and returning 0, thanks to the way the remote_driver
tracks things (in fact, the RPC wire protocol is unable to
send a return value for DomainEventRegisterAny, at least not
without adding a new RPC number).  Well, except for vbox,
which was always failing deregistration, due to failure to
set the return value to anything besides its initial -1.

But for local drivers, such as test:///default, we've been
returning non-zero numbers; worse, the non-zero numbers have
differed over time.  For example, in Fedora 12 (libvirt 0.8.2),
calling Register twice would return 0 and 1 [the callbackID
generated under the hood]; while in Fedora 20 (libvirt 1.1.3),
it returns 1 and 2 [the number of callbacks registered for
that event type].  Since we have changed the behavior over
time, and since it differs by local vs. remote, we can safely
argue that no one could have been reasonably relying on any
particular behavior, so we might as well obey the docs, as well
as prepare callers that might deal with older clients to not be
surprised if the docs are not strictly followed.

For consistency, this patch fixes the code for all drivers,
even though it only makes an impact for vbox and for local
drivers.  By fixing all drivers, future copy and paste from
a remote driver to a local driver is less likely to
reintroduce the bug.

Finally, update the testsuite to gain some coverage of the
issue for local drivers, including the first test of old-style
domain event registration via function pointer instead of
event id.

* src/libvirt.c (virConnectDomainEventRegister)
(virConnectDomainEventDeregister)
(virConnectDomainEventDeregisterAny): Clarify docs.
* src/libxl/libxl_driver.c (libxlConnectDomainEventRegister)
(libxlConnectDomainEventDeregister)
(libxlConnectDomainEventDeregisterAny): Match documentation.
* src/lxc/lxc_driver.c (lxcConnectDomainEventRegister)
(lxcConnectDomainEventDeregister)
(lxcConnectDomainEventDeregisterAny): Likewise.
* src/test/test_driver.c (testConnectDomainEventRegister)
(testConnectDomainEventDeregister)
(testConnectDomainEventDeregisterAny)
(testConnectNetworkEventDeregisterAny): Likewise.
* src/uml/uml_driver.c (umlConnectDomainEventRegister)
(umlConnectDomainEventDeregister)
(umlConnectDomainEventDeregisterAny): Likewise.
* src/vbox/vbox_tmpl.c (vboxConnectDomainEventRegister)
(vboxConnectDomainEventDeregister)
(vboxConnectDomainEventDeregisterAny): Likewise.
* src/xen/xen_driver.c (xenUnifiedConnectDomainEventRegister)
(xenUnifiedConnectDomainEventDeregister)
(xenUnifiedConnectDomainEventDeregisterAny): Likewise.
* src/network/bridge_driver.c
(networkConnectNetworkEventDeregisterAny): Likewise.
* tests/objecteventtest.c (testDomainCreateXMLOld): New test.
(mymain): Run it.
(testDomainCreateXML): Check return values.
Signed-off-by: NEric Blake <eblake@redhat.com>

The datatype.c object checks could result in a message like:

error: invalid connection pointer in no connection

This consolidates all clients of this message to have uniform contents:

error: invalid connection pointer in someFunc

Note that virCheckConnectReturn raises an error immediately; in
datatypes.c, where we don't need to raise the error (but instead
just leave it in the thread-local setting), we use
virCheckConnectGoto and the cleanup label instead.  Then, for
consistency in that file, all subsequent error messages are
touched to also use the cleanup error label.

* src/datatypes.h (virCheckConnectReturn)
(virCheckConnectGoto): New macros.
* src/datatypes.c: Use new macro.
* src/libvirt-qemu.c (virDomainQemuAttach): Likewise.
(virLibConnError): Delete unused macro.
* src/libvirt-lxc.c (virLibConnError): Likewise.
* src/libvirt.c: Use new macro throughout.
* docs/api_extension.html.in: Modernize documentation.
Signed-off-by: NEric Blake <eblake@redhat.com>

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 baa72449).

* 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: NEric Blake <eblake@redhat.com>

We weren't very consistent in our use of VIR_ERR_NO_SUPPORT; many
users just passed __FUNCTION__ on, while others passed "%s" to
silence over-eager compilers that warn about __FUNCTION__ not
containing any %.  It's nicer to route all these uses through
a single macro, so that if we ever need to change the reporting,
we can do it in one place.

I verified that 'virsh -c test:///default qemu-monitor-command test foo'
gives the same error message before and after this patch:
error: this function is not supported by the connection driver: virDomainQemuMonitorCommand

Note that in libvirt.c, we were inconsistent on whether virDomain*
API used virLibConnError() (with VIR_FROM_NONE) or virLibDomainError()
(with VIR_FROM_DOMAIN); this patch unifies these errors to all use
VIR_FROM_NONE, on the grounds that it is unlikely that a caller
learning that a call is unimplemented can do anything in particular
with extra knowledge of which error domain it belongs to.

One particular change to note is virDomainOpenGraphics which was
trying to fail with VIR_ERR_NO_SUPPORT after a failed
VIR_DRV_SUPPORTS_FEATURE check; all other places that fail a
feature check report VIR_ERR_ARGUMENT_UNSUPPORTED.

* src/util/virerror.h (virReportUnsupportedError): New macro.
* src/libvirt-qemu.c: Use new macro.
* src/libvirt-lxc.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
* src/security/security_manager.c: Likewise.
* src/util/virinitctl.c: Likewise.
* src/libvirt.c: Likewise.
(virDomainOpenGraphics): Use correct error for unsupported feature.
Signed-off-by: NEric Blake <eblake@redhat.com>

Having one API call into another is generally not good; among
other issues, it gives confusing logs, and is not quite as
efficient.

This fixes several instances, but not all: we still have instances
in both libvirt.c and in backend hypervisors (lxc and qemu) calling
the public virTypedParamsGetString and friends, which dispatch
errors immediately.  I'm not sure if it is worth trying to clean
that up in a separate patch (such a cleanup may be easiest by
separating the public function into a wrapper around the internal,
then tweaking internal.h so that internal users directly use the
internal function).

* src/libvirt.c (virDomainGetUUIDString, virNetworkGetUUIDString)
(virStoragePoolGetUUIDString, virSecretGetUUIDString)
(virNWFilterGetUUIDString): Avoid nested public API call.
* src/util/virtypedparam.c (virTypedParamsReplaceString): Don't
dispatch errors here.
(virTypedParamsGet): No need to reset errors.
(virTypedParamsGetBoolean): Use consistent ordering.
Signed-off-by: NEric Blake <eblake@redhat.com>

We document that calling any public API wipes out all prior
libvirt errors in the same thread; but weren't obeying this
style in a few functions.

There are a couple of nested uses of virConnectRef (in lxc
and qemu reboot paths), but they should not be affected by
this change in semantics since there should not be any
previous error getting nuked (a later patch will clean up
the nested calls, along with abuse of virConnectClose on
cleanup paths which DOES nuke errors).

* src/libvirt.c (virGetVersion, virConnectRef, virDomainRef)
(virDomainGetSecurityLabel, virDomainGetSecurityLabelList)
(virDomainSetMetadata, virDomainGetMetadata)
(virNodeGetSecurityModel, virNetworkRef, virInterfaceRef)
(virStoragePoolRef, virStorageVolRef, virNodeDeviceGetName)
(virNodeDeviceRef, virSecretRef, virStreamRef, virNWFilterRef)
(virDomainSnapshotRef): Reset error on entrance.
(do_open): Drop redundant error reset.
* src/libvirt-qemu.c (virDomainQemuAgentCommand): Likewise.
* src/libvirt-lxc.c (virDomainLxcEnterNamespace)
(virDomainLxcEnterSecurityLabel): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

While auditing error messages in libvirt.c, I found a couple
instances that had not been converted to modern error styles,
and a few places that failed to dispatch the error through
the known-good connection.

* src/libvirt.c (virDomainPinEmulator, virDomainGetDiskErrors)
(virDomainSendKey, virDomainGetSecurityLabelList)
(virDomainGetEmulatorPinInfo): Use typical error reporting.
(virConnectGetCPUModelNames, virConnectRegisterCloseCallback)
(virConnectUnregisterCloseCallback, virDomainGetUUID): Report
error through connection.
Signed-off-by: NEric Blake <eblake@redhat.com>

Style only.  In particular, the message on "flags 'affect live'
and 'affect config'" being mutually exclusive was already split
in some instances.

* src/libvirt.c: Wrap some long error messages to fit in 80 columns.
Signed-off-by: NEric Blake <eblake@redhat.com>

Most of our public APIs emit a debug log on entry, prior to anything
else.  There were a few exceptions where obvious failures were not
logged, so fix those.  When moving a debug earlier, this patch also
makes sure to avoid any NULL dereference during the log (the APIs
are supposed to gracefully fail if the user passes NULL for the object).

However, do NOT use VIR_DEBUG prior to virInitialize, since setting
up the error reporting can change where VIR_DEBUG output would be
routed.  Instead add documentation to virGlobalInit, virInitialize,
and virGetVersion that better explains initialization.

* src/libvirt.c (virGetVersion, virConnectRef, virDomainRef)
(virNetworkRef, virInterfaceRef, virStoragePoolRef)
(virStorageVolRef, virNodeDeviceRef, virSecretRef, virStreamRef)
(virNWFilterRef, virDomainSnapshotRef): Debug on function entry.
* src/libvirt-lxc.c (virDomainLxcEnterNamespace)
(virDomainLxcEnterSecurityLabel): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

I noticed that the virDomainQemuMonitorCommand debug output wasn't
telling me the name of the domain it was working on.  While it was
easy enough to determine which pointer matches the domain based on
other log messages, it is nicer to be consistent.

* src/util/viruuid.h (VIR_UUID_DEBUG): Moved here from...
* src/libvirt.c (VIR_UUID_DEBUG): ...here.
(VIR_ARG15, VIR_HAS_COMMA, VIR_DOMAIN_DEBUG_EXPAND)
(VIR_DOMAIN_DEBUG_PASTE, VIR_DOMAIN_DEBUG_0, VIR_DOMAIN_DEBUG_1)
(VIR_DOMAIN_DEBUG_2, VIR_DOMAIN_DEBUG): Move...
* src/datatypes.h: ...here.
* src/libvirt-qemu.c (virDomainQemuMonitorCommand)
(virDomainQemuAgentCommand): Better debug messages.
* src/libvirt-lxc.c (virDomainLxcOpenNamespace): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Preliminary cleanups to make search-and-replace easier in later
patches.  Many of these were done by grepping for (multiline)
pattern violations, then bundled all into one patch.

* src/libvirt.c: Uniform two spaces between functions, return
type and open brace on separate line, avoid blank lines around
open brace, label in column 1, drop redundant (), consistent
indentation for function headers split across lines.
Signed-off-by: NEric Blake <eblake@redhat.com>

Since libvirt 0.9.3, the entire virevent.c file has been a public
API, so improve the documentation in this file.  Also, fix a
potential core dump - it could only be triggered by bogus use of
the API and would only affect the caller (not libvirtd), but we
might as well be nice.

* src/libvirt.c (virConnectSetKeepAlive)
(virConnectDomainEventRegister, virConnectDomainEventRegisterAny)
(virConnectNetworkEventRegisterAny): Document event loop requirement.
* src/util/virevent.c (virEventAddHandle, virEventRemoveHandle)
(virEventAddTimeout, virEventRemoveTimeout): Likewise.
(virEventUpdateHandle, virEventUpdateTimeout): Likewise, and avoid
core dump if caller didn't register handler.
(virEventRunDefaultImpl): Expand example, and set up code block in
html docs.
(virEventRegisterImpl, virEventRegisterDefaultImpl): Document more
on the use of the event loop.
Signed-off-by: NEric Blake <eblake@redhat.com>