readline-devel is an optional build dependency; when it is not
present, the output of 'virsh <<EOF ... EOF' is different in that the
input provided by the user is not echoed, and prompts become
interleaved on the same line as actual output, which in turn causes
the sed doing prompt filtering to mess up:

| ./virsh-snapshot
| --- exp	2019-07-31 18:42:31.107399428 -0300
| +++ out.cooked	2019-07-31 18:42:31.108399437 -0300
| @@ -1,8 +1,3 @@
| -
| -
| -Domain snapshot s3 created from 's3.xml'
| -Domain snapshot s2 created from 's2.xml'
| -Name:           s2
|  Domain:         test
|  Current:        yes
|  State:          running

Maybe we should fix virsh in interactive mode to echo regardless of
whether readline-devel was used, but the quicker fix is to make the
test use 'virsh "..."' rather than reading its input from stdin.
Reported-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: NEric Blake <eblake@redhat.com>
Tested-by: NDaniel Henrique Barboza <danielhb413@gmail.com>

Earlier patches mentioned that the initial implementation will prevent
snapshots and checkpoints from being used on the same domain at once.
However, the actual restriction is done in this separate patch to make
it easier to lift that restriction via a revert, when we are finally
ready to tackle that integration in the future.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

Creating an 'exp' output file, but never comparing it against the
actual output, does not actually constitute testing the output. :)

Fixes: 280a2b41Signed-off-by: NEric Blake <eblake@redhat.com>

Changes noticed while copying to similar aspects of checkpoints.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

Any message that is easy to trigger (as evidenced by the testsuite
update) should not use 'internal error' as its category.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

The code to check whether a redefined snapshot/checkpoint XML is
attempting to create a cycle in the list of moments is lengthy, and
common between the two types of list. Therefore, it belongs in the
shared base file.
Signed-off-by: NEric Blake <eblake@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

We've been doing a terrible job of performing XML validation in our
various API that parse XML with a corresponding schema (we started
with domains back in commit dd69a14f, v1.2.12, but didn't catch all
domain-related APIs, didn't document the use of the flag, and didn't
cover other XML). New APIs (like checkpoints) should do the validation
unconditionally, but it doesn't hurt to continue retrofitting existing
APIs to at least allow the option.

While there are many APIs that could be improved, this patch focuses
on wiring up a new snapshot XML creation flag through all the
hypervisors that support snapshots, as well as exposing it in 'virsh
snapshot-create'.  For 'virsh snapshot-create-as', we blindly set the
flag without a command-line option, since the XML we create from the
command line should generally always comply (note that validation
might cause failures where it used to succeed, such as if we tighten
the RNG to reject a name of '../\n'); but blindly passing the flag
means we also have to add in fallback code to disable validation if
the server is too old to understand the flag.
Signed-off-by: NEric Blake <eblake@redhat.com>
Acked-by: NPeter Krempa <pkrempa@redhat.com>

In a constrained CI environment, where it is intentional that attempts
to write outside the current directory will fail, virsh-snapshot was
failing:

@@ -1,2 +1,3 @@
 error: invalid argument: parent s3 for snapshot s2 not found
 error: marker
+error: Failed to create '/home/travis/.cache/libvirt/virsh': Permission denied
FAIL virsh-snapshot (exit status: 1)

But we've already solved the problem in virsh-uriprecedence: tell
virsh to use XDG locations pointing to somewhere we can write rather
than its default of falling back to $HOME with the test being at risk
of breaking due to the user's environment and/or unacceptably altering
the user's normal cache.  Hoist that solution into test-lib.sh, so
that all scripts can use it as needed. While at it, fix a latent typo
where XDG_RUNTIME_HOME was set to a literal relative directory name
"XDG_CACHE_HOME" (the typo did not affect virsh-uriprecedence, but
could matter to other clients).

Fixes: 280a2b41
Fixes: 398de147Reported-by: NDaniel P. Berrangé <berrange@redhat.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Had this been in place earlier, I would have avoided the bugs in
commit 0baf6945 and 55c2ab3e. Writing the test required me to extend
the power of virsh - creating enough snapshots to cause fanout
requires enough input in a single session that adding comments and
markers makes it easier to check that output is correct. It's still a
bit odd that with test:///default, reverting to a snapshot changes the
domain from running to paused (possibly a bug in how the test driver
copied from the qemu driver) - but the important part is that the test
is reproducible, and any future tweaks we make to snapshot code have
less chance of breaking successful command sequences.
Signed-off-by: NEric Blake <eblake@redhat.com>
Acked-by: NMichal Privoznik <mprivozn@redhat.com>