Some cleanup paths overwrite a usefull error message with a less useful
one and we then try to preserve the original message. The handlers added
in this patch will simplify the operations since they are designed right
for the purpose.

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

The helper makes sure that strings passed to APIs are non-NULL and
non-empty. This allows to drop some inlined checks where it does not
make sense.

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>

This is the only callsite.

We drop use of localerror.name here, because it's not actually useful
to us: rather than the parameter name which received an invalid value
(which was assumed), it's actually the the dbus errno equivalent.
Just use the error string.
Acked-by: NEric Blake <eblake@redhat.com>

Some of these are leftovers from renaming the files, others
are just typos.

Also introduce an ugly awk script to enforce this.

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>

* src/util/virerror.h (virReportInvalidZeroArg): Fix double space.
Signed-off-by: NEric Blake <eblake@redhat.com>

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>

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>

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c

Nearly every source file does something like

  #define VIR_FROM_THIS VIR_FROM_FOO
  #define virFooReportErorr(code, ...) \
     virReportErrorHelper(VIR_FROM_THIS, code,  __FILE__,    \
                          __FUNCTION__, __LINE__, \
                          __VA_ARGS__)

This creates needless duplication and inconsistent error
reporting function names in each file. It is trivial to
just have virterror_internal.h provide a virReportError
macro that is equivalent

* src/util/virterror_internal.h: Define virReportError(code, ...)
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

To ensure consistent error reporting of invalid arguments,
provide a number of predefined helper methods & macros.

 - An arg which must not be NULL:

   virCheckNonNullArgReturn(argname, retvalue)
   virCheckNonNullArgGoto(argname, label)

 - An arg which must be NULL

   virCheckNullArgGoto(argname, label)

 - An arg which must be positive (ie 1 or greater)

   virCheckPositiveArgGoto(argname, label)

 - An arg which must not be 0

   virCheckNonZeroArgGoto(argname, label)

 - An arg which must be zero

   virCheckZeroArgGoto(argname, label)

 - An arg which must not be negative (ie 0 or greater)

   virCheckNonNegativeArgGoto(argname, label)

* src/libvirt.c, src/libvirt-qemu.c,
  src/nodeinfo.c, src/datatypes.c: Update to use
  virCheckXXXX macros
* po/POTFILES.in: Add libvirt-qemu.c and virterror_internal.h
* src/internal.h: Define macros for checking invalid args
* src/util/virterror_internal.h: Define macros for reporting
  invalid args
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

While we still don't want to enable gcc's new -Wformat-literal
warning, I found a rather easy case where the warning could be
reduced, by getting rid of obsolete error-reporting practices.
This is the last place where we were passing the (unused) net
and conn arguments for constructing an error.

* src/util/virterror_internal.h (virErrorMsg): Delete prototype.
(virReportError): Delete macro.
* src/util/virterror.c (virErrorMsg): Make static.
* src/libvirt_private.syms (virterror_internal.h): Drop export.
* src/util/conf.c (virConfError): Convert to macro.
(virConfErrorHelper): New function, and adjust error calls.
* src/xen/xen_hypervisor.c (virXenErrorFunc): Delete.
(xenHypervisorGetSchedulerType)
(xenHypervisorGetSchedulerParameters)
(xenHypervisorSetSchedulerParameters)
(xenHypervisorDomainBlockStats)
(xenHypervisorDomainInterfaceStats)
(xenHypervisorDomainGetOSType)
(xenHypervisorNodeGetCellsFreeMemory, xenHypervisorGetVcpus):
Update callers.

The compiler might optimize based on our declaration that something
is unused.  Putting that declaration in the header risks getting
out of sync with the actual implementation, so it belongs better
only in the .c files.  We were mostly compliant, and a new syntax
check will help us in the future.

* cfg.mk (sc_avoid_attribute_unused_in_header): New syntax check.
* src/nodeinfo.h (nodeGetCPUStats, nodeGetMemoryStats): Delete
attribute already present in .c file.
* src/qemu/qemu_domain.h (qemuDomainEventFlush): Likewise.
* src/util/virterror_internal.h (virReportErrorHelper): Parameters
are actually used by .c file.
* src/xenxs/xen_sxpr.h (xenFormatSxprDisk): Adjust prototype.
* src/xenxs/xen_sxpr.c (xenFormatSxprDisk): Delete unused argument.
(xenFormatSxpr): Adjust caller.
* src/xen/xend_internal.c (xenDaemonAttachDeviceFlags)
(xenDaemonUpdateDeviceFlags): Likewise.
Suggested by Daniel Veillard.

And from all related macros and functions.

Add a hook to the error reporting APIs to allow specific
error messages to be filtered out. Wire up libvirtd to
remove VIR_ERR_NO_DOMAIN & similar error codes from the
logs. They are still logged at DEBUG level.

* daemon/libvirtd.c: Filter VIR_ERR_NO_DOMAIN and friends
* src/libvirt_private.syms, src/util/virterror.c,
  src/util/virterror_internal.h: Hook for changing error
  reporting level

This reverts the additions in commit

  abff683f

taking us back to state where all errors are fully logged
in both libvirtd and normal clients.

THe intent was to stop VIR_ERR_NO_DOMAIN (No such domain
with UUID XXXX) messages from client apps polluting syslog
The change affected all error codes, but more seriously,
it also impacted errors from internal libvirtd infrastructure
For example guest autostart no longer logged errors. The
libvirtd network code no longer logged some errors. This
makes debugging incredibly hard

* daemon/libvirtd.c: Remove error log priority filter
* src/util/virterror.c, src/util/virterror_internal.h: Remove
  callback for overriding log priority

This reverts commit

 Log all errors at level INFO to stop polluting syslog
 04bd0360.

and makes virRaiseErrorFull() log errors at debug priority
when called from inside libvirtd. This stops libvirtd from
polluting it's own log with client errors at error priority
that'll be reported and logged on the client side anyway.

* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done

Can be used to re-set an old error, which may have been squashed by
other functions (like cleanup routines). Will be used in subsequent patches

The virRaiseErrorFull() may invoke the error handler callback
functions an application has registered. This is not good
because the connection object may not be available at this
point, and the caller may be holding locks. This creates a
problem if the error handler calls back into libvirt.

The solutuon is to move invocation of the handler into the
final cleanup code in the public API entry points, where it
is guarenteed to have safe state.

* src/libvirt.c: Invoke virDispatchError() in all error paths
* src/util/virterror.c: Remove virSetConnError/virSetGlobalError,
  replacing with virDispatchError(). Move invocation of the
  error callbacks into virDispatchError() instead of the
  virRaiseErrorFull function which is not in a safe context

* src/bridge.c, src/bridge.h, src/buf.c, src/buf.h, src/cgroup.c,
  src/cgroup.h, src/conf.c, src/conf.h, src/event.c, src/event.h,
  src/hash.c, src/hash.h, src/hostusb.c, src/hostusb.h,
  src/iptables.c, src/iptables.h, src/logging.c, src/logging.h,
  src/memory.c, src/memory.h, src/pci.c, src/pci.h, src/qparams.c,
  src/qparams.h, src/stats_linux.c, src/stats_linux.h,
  src/threads-pthread.c, src/threads-pthread.h, src/threads-win32.c,
  src/threads-win32.h, src/threads.c, src/threads.h, src/util.c,
  src/util.h, src/uuid.c, src/uuid.h, src/virterror.c,
  src/virterror_internal.h, src/xml.c, src/xml.h: Move all files
  into src/util/
* daemon/Makefile.am: Add -Isrc/util/ to build flags
* src/Makefile.am: Add -Isrc/util/ to build flags and update for
  moved files
* src/libvirt_private.syms: Export cgroup APIs since they're now
  in util rather than linking directly to drivers
* src/xen/xs_internal.c: Disable bogus virEventRemoveHandle call
  when built under PROXY
* proxy/Makefile.am: Update for changed file locations. Remove
  bogus build of event.c
* tools/Makefile.am, tests/Makefile.am: Add -Isrc/util/ to build flags

GCC >= 4.4 assumes the 'printf' attribute refers to the native
runtime libraries format specifiers. Thanks to gnulib, libvirt
has GNU format specifiers everywhere.  This means we need to
use 'gnu_printf' with GCC >= 4.4 to get correct compiler
checking of printf format specifiers.

* HACKING: Document new rules for ATTRIBUTE_FMT_PRINTF
* autobuild.sh, mingw32-libvirt.spec.in: Disable OpenNebula
  driver on mingw32 builds
* qemud/dispatch.h, qemud/qemu.h, src/buf.h src/internal.h,
  src/logging.h, src/security.h, src/sexpr.h, src/util.h,
  src/virterror_internal.h, src/xend_internal.c: Change
  over to ATTRIBUTE_FMT_PRINTF.
* src/virsh.c: Disable 'cd' and 'pwd' commands on Win32
  since they don't compile
* src/threads-win32.c: Add missing return value check

* src/virterror.c (virStrerror): Remove "static".
* src/virterror_internal.h (virStrerror): Declare it.
* src/libvirt_private.syms: Add virStrerror;