virDomainSnapshotFindByName(list, NULL) should return NULL, rather
than the internal-use-only metaroot. Most existing callers pass in a
non-NULL name; the few external callers that don't are immediately
calling virDomainMomentSetParent (which indeed needs the metaroot
rather than NULL if the parent name is NULL); but as the leaky
abstraction is ugly, it is worth instead making
virDomainMomentSetParent static and adding a new function for
resolving the parent link of a brand new moment within its list. The
existing external uses of virDomainMomentSetParent always succeed
(either the new moment has parent_name of NULL to become a new root,
or has parent_name set to a strdup of the previous current moment);
hence, our new function does not need a return value (but it still has
a VIR_WARN in case future uses break our assumptions about failure
being impossible).
Missed when commit 02c4e24d refactored things to attempt to remove
direct metaroot manipulations out of the qemu and test drivers into
internal-only details, and made more obvious when commit dc8d3dc6
factored it out into a separate file.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel 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: Eric Blake <eblake@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
This brings about a couple of benefits:
- use of VIR_AUTOUNREF() simplifies several callers
- Fixes a todo about virDomainMomentObjList not being polymorphic enough
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
VIR_CLASS_NEW insists that descendents of virObject have 'parent' as
the name of their inherited base class member at offset 0. While it
would be possible to write a new class-creation macro that takes the
actual field name, and rewrite VIR_CLASS_NEW to call the new macro
with the hard-coded name 'parent', so that we could make
virDomainMomentDef use a custom name for its base class, it seems less
confusing if all object code uses similar naming. Thus, this is a
mechanical rename in preparation of making virDomainSnapshotDef a
descendent of virObject, when we can no longer use 'parent' for a
different purpose than the base class.
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Peter Krempa <pkrempa@redhat.com>
'viralloc.h' does not provide any type or macro which would be necessary
in headers. Prevent leakage of the inclusion.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Commit b647d2195 introduced a use-after-free situation when the caller
is trying to delete a snapshot and its children: if the callback
function deletes the parent, it is no longer safe to query the parent
to learn which children also need to be deleted (where we previously
saved deleting the parent for last). To fix the problem, while still
maintaining support for topological visits of callback functions, we
have to stash off any information needed for later traversal prior to
using a callback function (virDomainMomentForEachChild already does
this, it is only virDomainMomentActOnDescendant that was running into
problems).
Sadly, the testsuite did not cover the problem at the time. Worse,
even though I later added commit 280a2b41e to catch problems like
this, and even though that test is indeed sufficient to detect the
problem when run under valgrind or suitable MALLOC_PERTURB_ settings,
I'm guilty of not running the test in such an environment. Thus,
v5.2.0 has a regression that could have been prevented had we used the
testsuite to its full power. On the bright side, deleting snapshots
requires ACL domain:snapshot, which is arguably as powerful as
domain:write, so I don't think this use-after-free forms a security
hole.
At some point, it would be nice to convert virDomainMomentObj into a
virObject, at which point, the solution is even simpler: add
virObjectRef/Unref around the callback. But as that will require
auditing even more places in the code, I went with the simplest patch
for the regression fix.
Fixes: b647d2195
Reported-by: Roman Bogorodskiy <bogorodskiy@gmail.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Tested-by: Roman Bogorodskiy <bogorodskiy@gmail.com>
Even though Coverity can prove that 'last' is always set if the prior
loop executed, gcc 8.0.1 cannot:
CC conf/libvirt_conf_la-virdomainmomentobjlist.lo
../../src/conf/virdomainmomentobjlist.c: In function 'virDomainMomentMoveChildren':
../../src/conf/virdomainmomentobjlist.c:178:19: error: 'last' may be used uninitialized in this function [-Werror=maybe-uninitialized]
last->sibling = to->first_child;
~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
Rewrite the loop to a form that should be easier for static analysis
to work with.
Fixes: ced0898f86
Reported-by: Bjoern Walk <bwalk@linux.ibm.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The qemu driver already had a full-blown virDomainMomentObjPtr to
check against, and the test driver ought to have one since we get
better error checking that the user passed in a valid object. Removes
the need for a helper function added in commit commit 4819f54b.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Rather than hard-coding the snapshot filter bit values into the
generic code, add another layer of indirection: callers must map which
of their public filter bits correspond to supported moment bits, then
pass two separate flags (the ones translated for moment code to
operate on, and the remaining ones for the filter callback to operate
on).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This functions tries to add a domain moment (love the name!) onto
a list of domain moments. Firstly, it checks if another moment
with the same name already exists. Then, it creates an empty
moment (without initializing its definition) and tries to add the
moment onto the list dereferencing moment definition in that
process. If it succeeds (which it never can), only after that it
sets moment->def.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The new code here very heavily resembles the code in
virDomainSnapshotObjList. There are still a couple of spots that are
tied a little too heavily to snapshots (the free function lacks a
polymorphic cleanup until we refactor code to use virObject; and an
upcoming patch will add internal VIR_DOMAIN_MOMENT_LIST flags to
replace the snapshot flag bits), but in general this is fairly close
to the state needed to add checkpoint lists.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Now that we have made virDomainMomentObj sufficiently generic to
support both snapshots and checkpoints, it is time to rename the file
that it lives in. The split between a generic object and a list of the
generic objects doesn't buy us as much, so it will be easier to stick
all the moment list code in one file, with more code moving in the
next patch. The changes during the move are fairly minor, although it
is worth pointing out that the log/error messages for the new file
report that they are from "domain", since the file will eventually be
shared by both "domain snapshot" and "domain checkpoint".
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
