qemu: snapshot: Convert if-else switch to switch statement

Convert the target snapshot state selector to a switch statement
enumerating all possible values. This points out a few mistakes in the
original selector.

The logic of the code is preserved until later patches.
qemu: snapshot: Reject revertion from clearly bad states

Report errors on some states snapshots done by qemu should never reach
examples: domtop: Fix uninitialized variable use

max_id could be used uninitialized in the cleanup section after the
domain wasn't found.

Discovered by Coverity.
examples: domtop: Avoid leaking memory

Use the virTypedParamsFree unconditionally as it handles NULL well and
has the benefit of freeing a typed parameter array even if it wasn't yet
assigned, but only allocated.
util: Check return value from virStrToLong* functions

We do so in the vast majority of places, so there's no problem of adding
the attribute to enforce it by the complier and fix a few leftover
places.

This was originally pointed out by Coverity as a recent change triggered
it's warning that our code checked the vast majority of returns from
virStrToLong_ui.
node_device: HAL: Ignore return value of virStrToLong_ui

Commit 5df813177c3b609a8cf5db26ae94b26d4a40063d forgot to adjust a few
callers of virStrToLong_ui to ignore the returned value in some ancient
parts of the code.
doc: Explicitly specify how to override spice channel mode

Be more clear that the "<channel mode=" attribute overrides the default
set by "defaultMode".

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1033704
schema: pool: netfs: Don't enforce slash in glusterfs pool source

Gluster volumes don't start with a leading slash. Our schema for netfs
gluster pools enforces it though. Luckily mount.glusterfs skips it.
Allow a slashless volume name for glusterfs netfs mounts in the schema.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1101999
getAdapterName: check for SCSI_HOST

Rather than assume that NOT FC_HOST is SCSI_HOST, let's call them out
specifically. Makes it easier to find SCSI_HOST code/structs and ensures
something isn't missed in the future
virStoragePoolSourceAdapter: Refine the SCSI_HOST adapter name

Preparation for future patches by creating a scsi_host union. For now,
just the 'name' will be present.
storage: Introduce parentaddr into virStoragePoolSourceAdapter

Between reboots and kernel reloads, the SCSI host number used for SCSI
storage pools may change requiring modification to the storage pool XML
in order to use a specific SCSI host adapter.

This patch introduces the "parentaddr" element and "unique_id" attribute
for the SCSI host adapter in order to uniquely identify the adapter
between reboots and kernel reloads. For now the goal is to only parse
and format the XML. Both will be required to be provided in order to
uniquely identify the desired SCSI host.

The new XML is expected to be as follows:

  <adapter type='scsi_host'>
    <parentaddr unique_id='3'>
      <address domain='0x0000' bus='0x00' slot='0x1f' func='0x2'/>
    </parentaddr>
  </adapter>

where "parentaddr" is the parent device of the SCSI host using the PCI
address on which the device resides and the value from the unique_id file
for the device. Both the PCI address and unique_id values will be used
to traverse the /sys/class/scsi_host/ directories looking at each link
to match the PCI address reformatted to the directory link format where
"domain:bus:slot:function" is found.  Then for each matching directory
the unique_id file for the scsi_host will be used to match the unique_id
value in the xml.

For a PCI address listed above, this will be formatted to "0000:00:1f.2"
and the links in /sys/class/scsi_host will be used to find the host#
to be used for the 'scsi_host' device. Each entry is a link to the
/sys/bus/pci/devices directories, e.g.:

%  ls -al /sys/class/scsi_host/host2
lrwxrwxrwx. 1 root root 0 Jun  1 00:22 /sys/class/scsi_host/host2 -> ../../devices/pci0000:00/0000:00:1f.2/ata3/host2/scsi_host/host2

% cat /sys/class/scsi_host/host2/unique_id
3

The "parentaddr" and "name" attributes are mutually exclusive to identify
the SCSI host number. Use of the "parentaddr" element will be the preferred
mechanism.

This patch only supports to parse and format the XMLs. Later patches will
add code to find out the scsi host number.
scsi_backend: Use existing LINUX_SYSFS_SCSI_HOST_PREFIX definition

Rather than supplying the path again in the formatting of the sysfs
scsi_host directory.
virutil: Introduce virReadSCSIUniqueId

Introduce a new function to read the current scsi_host entry and return
the value found in the 'unique_id' file.

Add a 'scsihosttest' test (similar to the fchosttest, but incorporating some
of the concepts of the mocked pci test library) in order to read the
unique_id file like would be found in the /sys/class/scsi_host tree.
Add unique_id to nodedev output

Add an optional unique_id parameter to nodedev.  Allows for easier lookup
and display of the unique_id value in order to document for use with
scsi_host code.
scsi_host: Introduce virFindSCSIHostByPCI

Introduce a new function to parse the provided scsi_host parent address
and unique_id value in order to find the /sys/class/scsi_host directory
which will allow a stable SCSI host address

Add a test to scsihosttest to lookup the host# name by using the PCI address
and unique_id value
getAdapterName: Lookup stable scsi_host

If a parentaddr was provided in the XML, have getAdapterName lookup
the stable address.  This allows virStorageBackendSCSICheckPool() and
virStorageBackendSCSIRefreshPool() to automagically find the scsi_host
by its PCI address and unique_id
Fix build on non-Linux platforms

Commit ef48a1b introduced virFindSCSIHostByPCI for Linux and
a stub for other platforms that returns -1 while the function
should return 'char *', so use 'return NULL' instead.

Commit fbd91d4 introduced virReadSCSIUniqueId with the third
argument 'int *result', however the stub for non-Linux patform
uses 'unsigned int *result', so change it to 'int *result'.

Pushed under the build breaker rule.
storage: logical: drop useless if

virStorageBackendLogicalCreateVol contains a piece like:

    if (vol->target.path != NULL) {
        /* A target path passed to CreateVol has no meaning */
        VIR_FREE(vol->target.path);
    }

The 'if' is useless here, but 'syntax-check' doesn't catch that
because of the comment, so drop the 'if'.
build: fix build without numactl

Under ./configure --without-numactl but with numactl-devel installed,
the build fails with:

../../src/util/virnuma.c: In function 'virNumaNodeIsAvailable':
../../src/util/virnuma.c:407:5: error: implicit declaration of function 'numa_bitmask_isbitset' [-Werror=implicit-function-declaration]
     return numa_bitmask_isbitset(numa_nodes_ptr, node);
     ^

and other failures, all because the configure results for particular
functions were used without regard to whether libnuma was even being
linked in.

* src/util/virnuma.c (virNumaGetPages): Fix message typo.
(virNumaNodeIsAvailable): Correct build when not using numactl.

Signed-off-by: Eric Blake <eblake@redhat.com>
domtop: Fix build on mingw

Firstly, there's no sigaction() nor struct sigaction on mingw. We have
to use the one implemented by gnulib (and hence link with gnulib).
Then, for some reason one header file from windows defines ERROR
symbol. Yes it does. Sigh.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>