This patch simplifies the creation of XML, some error paths and adds
correct approach to check for virBuffer errors.

The query didn't match the external state correctly for offline internal
snapshots.

also avoids potential NULL pointer dereference:

$ virsh snapshot-current asdf ""
error: invalid snapshotname argument '(null)'

by removing the error message in favor of vshCommandOptStringReq

This patch simplifies error paths and switches to use
vshCommandOptStringReq for argument retrieval in cmdSnapshotDumpXML

buffer won't be NULL in any case when reaching the check and the first
block of the if statement was lacking parentheses

Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When the value of memspec was empty taking of a snapshot failed without
reporting an error.

Now that we can filter on this information, we should also make
it easy to get at.

* tools/virsh-snapshot.c (cmdSnapshotInfo): Add another output
row, and switch to XPath queries rather than strstr.

Snapshot filtering based on types is useful enough to add
back-compat support into virsh.  It is also rather easy - all
versions of libvirt that don't understand the new filter flags
already gave us sufficient information in a single XML field
to reconstruct all the information we need (that is, it isn't
until libvirt 1.0.1 that we have more interesting types of
snapshots, such as offline external).

* tools/virsh-snapshot.c (vshSnapshotFilter): New function.
(vshSnapshotListCollect): Add fallback support.

As we enable more modes of snapshot creation, it becomes more important
to be able to quickly filter based on snapshot properties.  This patch
introduces new filter flags; subsequent patches will introduce virsh
back-compat filtering, as well as actual libvirt filtering.

* include/libvirt/libvirt.h.in (virDomainSnapshotListFlags): Add
five new flags in two new groups.
* src/libvirt.c (virDomainSnapshotNum, virDomainSnapshotListNames)
(virDomainListAllSnapshots, virDomainSnapshotNumChildren)
(virDomainSnapshotListChildrenNames)
(virDomainSnapshotListAllChildren): Document them.
* src/conf/snapshot_conf.h (VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS)
(VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION): Add new convenience filter
collection macros.
* tools/virsh-snapshot.c (cmdSnapshotList): Add 5 new flags.
* tools/virsh.pod (snapshot-list): Document them.

If the domain can't be looked up, name is used unitialized after the
cleanup label.

Found by coverity.

External checkpoints could be created with snapshot-create, but
without libvirt supplying a default name for the memory file,
it is essential to add a new argument to snapshot-create-as to
allow the user to choose the memory file name.  This adds the
option --memspec [file=]name[,snapshot=type], where type can
be none, internal, or external.  For an example,

virsh snapshot-create-as $dom --memspec /path/to/file

is the shortest possible command line for creating an external
checkpoint, named after the current timestamp.

* tools/virsh-snapshot.c (vshParseSnapshotMemspec): New function.
(cmdSnapshotCreateAs): Use it.
* tests/virsh-optparse (test_url): Test it.
* tools/virsh.pod (snapshot-create-as): Document it.

So far, none of the existing callers of vshStringToArray expected
the user to ever pass a literal comma; meanwhile, snapshot parsing
had rolled its own array parser.  Moving the comma escaping into
the common function won't affect any existing callers, and will make
this function reusable for adding memory handling to snapshot parsing.

As a bonus, the testsuite was already testing snapshot parsing, so
the fact that the test still passes means that we are now giving
testsuite exposure to vshStringToArray.

* tools/virsh-snapshot.c (vshParseSnapshotDiskspec): Move ,,
parsing...
* tools/virsh.c (vshStringToArray): ...into common function.
Also, vshStrdup can't fail.

The default behavior while creating external checkpoints is to pause the
guest while the memory state is captured. We want the users to sacrifice
space saving for creating the memory save image while the guest is live
to minimize downtime.

This patch adds a flag that causes the guest not to be paused before
taking the snapshot.
 *include/libvirt/libvirt.h.in:
    - add new paused reason: VIR_DOMAIN_PAUSED_SNAPSHOT
    - add new flag for taking snapshot: VIR_DOMAIN_SNAPSHOT_CREATE_LIVE
 *tools/virsh-domain-monitor.c:
    - add string representation for VIR_DOMAIN_PAUSED_SNAPSHOT
 *tools/virsh-snapshot.c:
    - add support for VIR_DOMAIN_SNAPSHOT_CREATE_LIVE
 *tools/virsh.pod:
    - add docs for --live option added to use
    VIR_DOMAIN_SNAPSHOT_CREATE_LIVE flag

https://bugzilla.redhat.com/show_bug.cgi?id=869100 mentioned some
confusion about 'virsh snapshot-list' errors.  Clean up a
misleading error message, and add some documentation.

* tools/virsh-snapshot.c (cmdSnapshotList): Mention --current
rather than --from when appropriate.
* tools/virsh.pod (snapshot-list): Mention that the named starting
point is NOT part of the list except under --tree.

'snaps' is used after free()'ed.

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/

Now that vshCommandRun() checks for the connection automaticaly, remove
all of the redundant checks in the code.

vshConnectionUsability() no longer needs to be exported and this patch
marks it static.

If xml is not changed, error message is printed.
So check ret value instead of edit variable for error message.

Almost done with the splits.

* tools/virsh-snapshot.h: New file.
* tools/Makefile.am (virsh_SOURCES): Build it.
* tools/virsh.c: Use new header.
* tools/virsh-snapshot.c: Likewise.

Convert the exported items in virsh.h to use a common 'vsh' prefix.

* tools/virsh.h (VIRSH_MAX_XML_FILE): Rename...
(VSH_MAX_XML_FILE): ...and parenthesize.
(DIFF_MSEC, CTRL_CLOSE_BRACKET): Delete.
(vshUsage, vshInit, vshDeinit, vshParseArgv): Remove prototype.
(editWriteToTempFile, editFile, editReadBackFile, prettyCapacity)
(virshReportError): Rename...
(vshEditWriteToTempFile, vshEditFile, vshEditReadBackFile)
(vshPrettyCapacity, vshReportError): ...into vsh namespace.
(jobWatchTimeoutFunc): Move to virsh-domain.c.
* tools/virsh.c (vshCommandRun): Inline former DIFF_MSEC.
(main): Inline former CTRL_CLOSE_BRACKET.
(vshUsage, vshInit, vshDeinit, vshParseArgv): Make static.
(prettyCapacity, virshReportError, editWriteToTempFile, editFile):
Fix naming, and adjust usage.
(vshAskReedit, vshCommandRun, vshEventLoop, vshInit): Adjust
usage.
* tools/virsh-domain.c (cmdAttachDevice, cmdCPUCompare)
(cmdCPUBaseline, cmdCreate, cmdDefine, cmdDetachDevice)
(cmdUpdateDevice, cmdDesc, cmdUndefine, cmdStart, cmdVcpucount)
(cmdAttachDevice, cmdDomjobinfo): Likewise.
* tools/virsh-edit.c (do): Likewise.
* tools/virsh-interface.c (cmdInterfaceDefine): Likewise.
* tools/virsh-network.c (cmdNetworkCreate, cmdNetworkDefine):
Likewise.
* tools/virsh-nodedev.c (cmdNodeDeviceCreate): Likewise.
* tools/virsh-nwfilter.c (cmdNWFilterDefine): Likewise.
* tools/virsh-pool.c (cmdPoolCreate, cmdPoolDefine)
(cmdPoolDiscoverSources, cmdPoolList): Likewise.
* tools/virsh-secret.c (cmdSecretDefine): Likewise.
* tools/virsh-snapshot.c (cmdSnapshotCreate, vshSnapshotCreate)
(vshLookupSnapshot, cmdSnapshotEdit, cmdSnapshotCurrent)
(vshGetSnapshotParent): Likewise.
* tools/virsh-volume.c (cmdVolCreate, cmdVolCreateFrom)
(cmdVolInfo, cmdVolList): Likewise.

* tools/virsh.c: New macro vshStrcasecmp
* tools/virsh-domain-monitor.c: Use vshStrcasecmp instead of
                                strcasecmp
* tools/virsh-snapshot.c: Likewise
* cfg.mk: Only avoid doing strcase checking for virsh.c

On some fallback paths in virsh, error reported by the previously failed
API is cleared by virResetLastError() that doesn't free error stored by
virsh. This patch changes this to clear it using vshResetLibvirtError().

Virsh uses an error handler to save errors from libvirt. On some code
paths it's needed to clear libvirt errors and continue on fallback code
paths without reporting failure.

This patch adds function vshResetLibvirtError() that clears error
returned by libvirt and updates all places where the old two-line method
was used.

* virsh-domain-monitor.c: Add domMonitoringCmds
* virsh-domain.c: Add domManagementCmds
* virsh-host.c: Add hostAndHypervisorCmds
* virsh-interface.c: Add ifaceCmds
* virsh-network.c: Add networkCmds
* virsh-nodedev.c: Add nodedevCmds
* virsh-nwfilter.c: Add nwfilterCmds
* virsh-pool.c: Add storagePoolCmds
* virsh-secret.c: Add secretCmds
* virsh-snapshot.c: Add snapshotCmds
* virsh-volume.c: Add storageVolCmds
* virsh.c: Remove all the above *Cmds.

Commands to manage domain snapshot are moved from virsh.c to
virsh-snapshot.c.

* virsh.c: Remove domain snapshot commands.
* virsh-snapshot.c: New file, filled with domain snapshot commands.
* po/POTFILES.in: Add virsh-snapshot.c
* cfg.mk: Skip strcase and config.h including checking for
          virsh-snapshot.c