virDomainMigrateFinish* APIs were unfortunately designed to return the
pointer to the domain on destination and NULL on error. This looks OK in
normal cases but the same API is also called when we know migration
failed and thus we expect Finish to return NULL even if it actually did
all it was supposed to do without any error. The call is defined to
return nonnull domain pointer over RPC, which means returning NULL will
always result in an error being send. If this was not in fact an error,
the API itself wouldn't set anything to the thread local virError, which
makes the RPC layer come up with it's own "Library function returned
error but did not set virError" error.

This is quite confusing and also hard to detect by the caller. This
patch adds a special error code which can be used to check that Finish
successfully aborted migration.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

A helper function for copying error objects.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Just the addition of VIR_FROM_ADMIN to the enum of error domains.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

It already had a virMutex inside, so this is just a cleanup.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

When acquiring resource via sanlock fails, we would report it as
VIR_ERR_INTERNAL_ERROR, which is not very friendly to applications using
libvirt. Moreover, the lockd driver would report the same failure as
VIR_ERR_RESOURCE_BUSY, which looks better.

Unfortunately, in sanlock driver we don't really know if acquiring the
resource failed because it was already locked or there was another
reason behind. But the end result is the same and I think using
VIR_ERR_RESOURCE_BUSY reason for all acquire failures is still better
than what we have now.

https://bugzilla.redhat.com/show_bug.cgi?id=1165119Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Each thread can use a thread local variable to keep the name of a job
which is currently running in the job.

The virThreadJobSetWorker API is supposed to be called once by any
thread which is used as a worker, i.e., it is waiting in a pool, woken
up to do a job, and returned back to the pool.

The virThreadJobSet/virThreadJobClear APIs are to be called at the
beginning/end of each job.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

The virDBusMethodCall method has a DBusError as one of its
parameters. If the caller wants to pass a non-NULL value
for this, it immediately makes the calling code require
DBus at build time. This has led to breakage of non-DBus
builds several times. It is desirable that only the virdbus.c
file should need WITH_DBUS conditionals, so we must ideally
remove the DBusError parameter from the method.

We can't simply raise a libvirt error, since the whole point
of this parameter is to give the callers a way to check if
the error is one they want to ignore, without having the logs
polluted with an error message. So, we add a virErrorPtr
parameter which the caller can then either ignore or raise
using the new virReportErrorObject method.

This new method is distinct from virSetError in that it
ensures the logging hooks are run.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add a helper method that can validate an XML document against
an RNG schema

There are now two places in libvirt which use polkit. Currently
they use pkexec, which is set to be replaced by direct DBus API
calls. Add a common API which they will both be able to use for
this purpose.

No tests are added at this time, since the impl will be gutted
in favour of a DBus API call shortly.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When CPU comparison APIs return VIR_CPU_COMPARE_INCOMPATIBLE, the caller
has no clue why the CPU is considered incompatible with host CPU. And in
some cases, it would be nice to be able to get such info in a client
rather than having to look in logs.

To achieve this, the APIs can be told to return VIR_ERR_CPU_INCOMPATIBLE
error for incompatible CPUs and the reason will be described in the
associated error message.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

The network and nwfilter drivers both have a need to update
firewall rules. The currently share no code for interacting
with iptables / firewalld. The nwfilter driver is fairly
tied to the concept of creating shell scripts to execute
which makes it very hard to port to talk to firewalld via
DBus APIs.

This patch introduces a virFirewallPtr object which is able
to represent a complete sequence of rule changes, with the
ability to have multiple transactional checkpoints with
rollbacks. By formally separating the definition of the rules
to be applied from the mechanism used to apply them, it is
also possible to write a firewall engine that uses firewalld
DBus APIs natively instead of via the slow firewalld-cmd.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Signed-off-by: NMartin Kletzander <mkletzan@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>

As part of the goal to get away from doing string matching on
filenames when deciding whether to emit a log message, turn
the virLogSource enum into a struct which contains a log
"name". There will eventually be one virLogSource instance
statically declared per source file. To minimise churn in this
commit though, a single global instance is used.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The error reporting code will invoke a callback when any error
is raised and the default callback will print to stderr. The
virRaiseErrorFull method also sends all error messages on to the
logging code, which also prints to stderr by default. To avoid
duplicated data on stderr, the logging code has some logic to
skip emission when no log outputs are configured, which checks
whether the virLogSource == VIR_LOG_FROM_ERROR.

Meanwhile the libvirtd daemon can register another callback which
is used to reduce log message priority from error to a lower level.
When this is used we do want messages to end up on stderr, so the
error code will conditionally use either VIR_LOG_FROM_FILE or
VIR_LOG_FROM_ERROR depending on whether such a callback is provided.

This will all complicate later refactoring. By pushing the checks
for whether a log output is present up a level into the error code,
the special cases can be isolated in one place.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

GNULIB provides APIs for calculating md5 and sha256 hashes,
but these APIs only return you raw byte arrays. Most users
in libvirt want the hash in printable string format. Add
some helper APIs in util/vircrypto.{c,h} for doing this.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When a virError is raised, pass the error domain and code
onto the systemd journald using metadata fields.

This allows error messages to be queried by code eg

  $ journalctl LIBVIRT_CODE=43
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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.

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 currently have other error codes in singular form, e.g.
VIR_ERR_NETWORK_EXIST. Cleanup the previous patch to match the form.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

I created a storage volume(eg: test) from a storage pool(eg:vg10) using
the following command:"virsh vol-create-as --pool vg10 --name test --capacity 300M."
When I re-executed the above command, the output was as the following:
"error: Failed to create vol test
 error: Storage volume not found: storage vol 'test' already exists"

I think the output "Storage volume not found" is not appropriate. Because in fact storage
vol test has been found at this time. And then I think virErrorNumber should includes
VIR_ERR_STORAGE_EXIST which can also be used elsewhere. So I make this patch. The result
is as following:
"error: Failed to create vol test
 error: storage volume 'test' exists already"

As we do for other errors with an extra string.

Add virErrorSetErrnoFromLastError and virLastErrorIsSystemErrno
to simplify code which wants to handle system errors in a more
graceful fashion.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

To register virtual machines and containers with systemd-machined,
and thus have cgroups auto-created, we need to talk over DBus.
This is somewhat tedious code, so introduce a dedicated function
to isolate the DBus call in one place.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Doing DBus method calls using libdbus.so is tedious in the
extreme. systemd developers came up with a nice high level
API for DBus method calls (sd_bus_call_method). While
systemd doesn't use libdbus.so, their API design can easily
be ported to libdbus.so.

This patch thus introduces methods virDBusCallMethod &
virDBusMessageRead, which are based on the code used for
sd_bus_call_method and sd_bus_message_read. This code in
systemd is under the LGPLv2+, so we're license compatible.

This code is probably pretty unintelligible unless you are
familiar with the DBus type system. So I added some API
docs trying to explain how to use them, as well as test
cases to validate that I didn't screw up the adaptation
from the original systemd code.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Actually, I'm turning this function into a macro as filename,
function name and line number needs to be passed. The new
function virAsprintfInternal is introduced with the extended set
of arguments.

Similarly to VIR_STRDUP, we want the OOM error to be reported in
VIR_ALLOC and friends.

This patch introduces the virAccessManagerPtr class as the
interface between virtualization drivers and the access
control drivers. The viraccessperm.h file defines the
various permissions that will be used for each type of object
libvirt manages
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Apps using libvirt will often have code like

   if (virXXXX() < 0) {
      virErrorPtr err = virGetLastError();
      fprintf(stderr, "Something failed: %s\n",
              err && err->message ? err->message :
              "unknown error");
      return -1;
   }

Checking for a NULL error object or message leads to very
verbose code. A virGetLastErrorMessage() helper from libvirt
can simplify this to

   if (virXXXX() < 0) {
      fprintf(stderr, "Something failed: %s\n",
              virGetLastErrorMessage());
      return -1;
   }
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

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.

Add a virCgroupIsolateMount method which looks at where the
current process is place in the cgroups (eg /system/demo.lxc.libvirt)
and then remounts the cgroups such that this sub-directory
becomes the root directory from the current process' POV.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Introduce a local object virIdentity for managing security
attributes used to form a client application's identity.
Instances of this object are intended to be used as if they
were immutable, once created & populated with attributes
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

BZ:https://bugzilla.redhat.com/show_bug.cgi?id=912021
Without error handler set, virDefaultErrorFunc will be called, the
error message is prefixed with "libvir:". It become a little better
by using prefix "libvirt:" when working with upper application.

For example:
1, stop libvirtd daemon
2, run virt-top.
libvir: XML-RPC error : Failed to connect \
        socket to '/var/run/libvirt/libvirt-sock-ro': \
        No such file or directory
libvirt: VIR_ERR_SYSTEM_ERROR: VIR_FROM_RPC: \
        Failed to connect socket to '/var/run/libvirt/libvirt-sock-ro': \
        No such file or directory

Way back when I started making changes for Coverity messages my first set
were to a bunch of CHECKED_RETURN errors.  In particular virAsprintf() had
a few callers that Coverity noted didn't check their return (although some
did check if the buffer being printed to was NULL or not).

It was suggested at the time as a further patch an ATTRIBUTE_RETURN_CHECK
should be added to virAsprintf(), see:

https://www.redhat.com/archives/libvir-list/2013-January/msg00120.html

This patch does that and fixes a few more instances not found by Coverity
that failed the check.