/*
* virdomainsnapshotobjlist.c: handle a tree of snapshot objects
* (derived from snapshot_conf.c)
*
* Copyright (C) 2006-2019 Red Hat, Inc.
* Copyright (C) 2006-2008 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* .
*/
#include
#include "internal.h"
#include "virdomainsnapshotobjlist.h"
#include "snapshot_conf.h"
#include "virlog.h"
#include "virerror.h"
#include "datatypes.h"
#include "virstring.h"
#define VIR_FROM_THIS VIR_FROM_DOMAIN_SNAPSHOT
VIR_LOG_INIT("conf.virdomainsnapshotobjlist");
struct _virDomainSnapshotObjList {
/* name string -> virDomainMomentObj mapping
* for O(1), lockless lookup-by-name */
virHashTable *objs;
virDomainMomentObj metaroot; /* Special parent of all root snapshots */
virDomainMomentObjPtr current; /* The current snapshot, if any */
};
/* Parse a XML entry into snapshots, which must start
* empty. Any sub-elements of a must match
* domain_uuid. @flags is virDomainSnapshotParseFlags. Return the
* number of snapshots parsed, or -1 on error.
*/
int
virDomainSnapshotObjListParse(const char *xmlStr,
const unsigned char *domain_uuid,
virDomainSnapshotObjListPtr snapshots,
virCapsPtr caps,
virDomainXMLOptionPtr xmlopt,
unsigned int flags)
{
int ret = -1;
xmlDocPtr xml;
xmlNodePtr root;
xmlXPathContextPtr ctxt = NULL;
int n;
size_t i;
int keepBlanksDefault = xmlKeepBlanksDefault(0);
virDomainMomentObjPtr snap;
VIR_AUTOFREE(xmlNodePtr *) nodes = NULL;
VIR_AUTOFREE(char *) current = NULL;
if (!(flags & VIR_DOMAIN_SNAPSHOT_PARSE_REDEFINE) ||
(flags & VIR_DOMAIN_SNAPSHOT_PARSE_INTERNAL)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("incorrect flags for bulk parse"));
return -1;
}
if (virDomainSnapshotObjListSize(snapshots) != 0) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("bulk define of snapshots only possible with "
"no existing snapshot"));
return -1;
}
if (!(xml = virXMLParse(NULL, xmlStr, _("(domain_snapshot)"))))
return -1;
root = xmlDocGetRootElement(xml);
if (!virXMLNodeNameEqual(root, "snapshots")) {
virReportError(VIR_ERR_XML_ERROR,
_("unexpected root element <%s>, "
"expecting "), root->name);
goto cleanup;
}
ctxt = xmlXPathNewContext(xml);
if (ctxt == NULL) {
virReportOOMError();
goto cleanup;
}
ctxt->node = root;
current = virXMLPropString(root, "current");
if ((n = virXPathNodeSet("./domainsnapshot", ctxt, &nodes)) < 0)
goto cleanup;
for (i = 0; i < n; i++) {
virDomainSnapshotDefPtr def;
def = virDomainSnapshotDefParseNode(xml, nodes[i], caps, xmlopt, NULL,
flags);
if (!def)
goto cleanup;
if (!(snap = virDomainSnapshotAssignDef(snapshots, def))) {
virDomainSnapshotDefFree(def);
goto cleanup;
}
if (virDomainSnapshotRedefineValidate(def, domain_uuid, NULL, NULL,
flags) < 0)
goto cleanup;
}
if (virDomainSnapshotUpdateRelations(snapshots) < 0) {
virReportError(VIR_ERR_XML_ERROR, "%s",
_(" contains inconsistent parent-child "
"relationships"));
goto cleanup;
}
if (current) {
snap = virDomainSnapshotFindByName(snapshots, current);
if (!snap) {
virReportError(VIR_ERR_NO_DOMAIN_SNAPSHOT,
_("no snapshot matching current='%s'"), current);
goto cleanup;
}
virDomainSnapshotSetCurrent(snapshots, snap);
}
ret = n;
cleanup:
if (ret < 0) {
/* There were no snapshots before this call; so on error, just
* blindly delete anything created before the failure. */
virDomainSnapshotObjListRemoveAll(snapshots);
}
xmlXPathFreeContext(ctxt);
xmlFreeDoc(xml);
xmlKeepBlanksDefault(keepBlanksDefault);
return ret;
}
/* Struct and callback function used as a hash table callback; each call
* appends another snapshot XML to buf, with the caller clearing the
* buffer if any callback fails. */
struct virDomainSnapshotFormatData {
virBufferPtr buf;
const char *uuidstr;
virCapsPtr caps;
virDomainXMLOptionPtr xmlopt;
unsigned int flags;
};
static int
virDomainSnapshotFormatOne(void *payload,
const void *name ATTRIBUTE_UNUSED,
void *opaque)
{
virDomainMomentObjPtr snap = payload;
struct virDomainSnapshotFormatData *data = opaque;
return virDomainSnapshotDefFormatInternal(data->buf, data->uuidstr,
virDomainSnapshotObjGetDef(snap),
data->caps, data->xmlopt,
data->flags);
}
/* Format the XML for all snapshots in the list into buf. @flags is
* virDomainSnapshotFormatFlags. On error, clear the buffer and return
* -1. */
int
virDomainSnapshotObjListFormat(virBufferPtr buf,
const char *uuidstr,
virDomainSnapshotObjListPtr snapshots,
virCapsPtr caps,
virDomainXMLOptionPtr xmlopt,
unsigned int flags)
{
struct virDomainSnapshotFormatData data = {
.buf = buf,
.uuidstr = uuidstr,
.caps = caps,
.xmlopt = xmlopt,
.flags = flags,
};
virCheckFlags(VIR_DOMAIN_SNAPSHOT_FORMAT_SECURE, -1);
virBufferAddLit(buf, "\n");
virBufferAdjustIndent(buf, 2);
if (virDomainSnapshotForEach(snapshots, virDomainSnapshotFormatOne,
&data) < 0) {
virBufferFreeAndReset(buf);
return -1;
}
virBufferAdjustIndent(buf, -2);
virBufferAddLit(buf, "\n");
return 0;
}
/* Snapshot Obj functions */
static virDomainMomentObjPtr virDomainMomentObjNew(void)
{
virDomainMomentObjPtr snapshot;
if (VIR_ALLOC(snapshot) < 0)
return NULL;
VIR_DEBUG("obj=%p", snapshot);
return snapshot;
}
static void virDomainMomentObjFree(virDomainMomentObjPtr snapshot)
{
if (!snapshot)
return;
VIR_DEBUG("obj=%p", snapshot);
virDomainSnapshotDefFree(virDomainSnapshotObjGetDef(snapshot));
VIR_FREE(snapshot);
}
virDomainMomentObjPtr virDomainSnapshotAssignDef(virDomainSnapshotObjListPtr snapshots,
virDomainSnapshotDefPtr def)
{
virDomainMomentObjPtr snap;
if (virHashLookup(snapshots->objs, def->common.name) != NULL) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("unexpected domain snapshot %s already exists"),
def->common.name);
return NULL;
}
if (!(snap = virDomainMomentObjNew()))
return NULL;
if (virHashAddEntry(snapshots->objs, snap->def->name, snap) < 0) {
VIR_FREE(snap);
return NULL;
}
snap->def = &def->common;
return snap;
}
/* Snapshot Obj List functions */
static bool
virDomainSnapshotFilter(virDomainMomentObjPtr obj,
unsigned int flags)
{
virDomainSnapshotDefPtr def = virDomainSnapshotObjGetDef(obj);
/* Caller has already sanitized flags and performed filtering on
* DESCENDANTS and LEAVES. */
if (flags & VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS) {
if (!(flags & VIR_DOMAIN_SNAPSHOT_LIST_INACTIVE) &&
def->state == VIR_DOMAIN_SNAPSHOT_SHUTOFF)
return false;
if (!(flags & VIR_DOMAIN_SNAPSHOT_LIST_DISK_ONLY) &&
def->state == VIR_DOMAIN_SNAPSHOT_DISK_SNAPSHOT)
return false;
if (!(flags & VIR_DOMAIN_SNAPSHOT_LIST_ACTIVE) &&
def->state != VIR_DOMAIN_SNAPSHOT_SHUTOFF &&
def->state != VIR_DOMAIN_SNAPSHOT_DISK_SNAPSHOT)
return false;
}
if ((flags & VIR_DOMAIN_SNAPSHOT_LIST_INTERNAL) &&
virDomainSnapshotIsExternal(obj))
return false;
if ((flags & VIR_DOMAIN_SNAPSHOT_LIST_EXTERNAL) &&
!virDomainSnapshotIsExternal(obj))
return false;
return true;
}
static void
virDomainSnapshotObjListDataFree(void *payload,
const void *name ATTRIBUTE_UNUSED)
{
virDomainMomentObjPtr obj = payload;
virDomainMomentObjFree(obj);
}
virDomainSnapshotObjListPtr
virDomainSnapshotObjListNew(void)
{
virDomainSnapshotObjListPtr snapshots;
if (VIR_ALLOC(snapshots) < 0)
return NULL;
snapshots->objs = virHashCreate(50, virDomainSnapshotObjListDataFree);
if (!snapshots->objs) {
VIR_FREE(snapshots);
return NULL;
}
return snapshots;
}
void
virDomainSnapshotObjListFree(virDomainSnapshotObjListPtr snapshots)
{
if (!snapshots)
return;
virHashFree(snapshots->objs);
VIR_FREE(snapshots);
}
struct virDomainMomentNameData {
char **const names;
int maxnames;
unsigned int flags;
int count;
bool error;
virDomainMomentObjListFilter filter;
};
static int virDomainMomentObjListCopyNames(void *payload,
const void *name ATTRIBUTE_UNUSED,
void *opaque)
{
virDomainMomentObjPtr obj = payload;
struct virDomainMomentNameData *data = opaque;
if (data->error)
return 0;
/* Caller already sanitized flags. Filtering on DESCENDANTS was
* done by choice of iteration in the caller. */
if ((data->flags & VIR_DOMAIN_SNAPSHOT_LIST_LEAVES) && obj->nchildren)
return 0;
if ((data->flags & VIR_DOMAIN_SNAPSHOT_LIST_NO_LEAVES) && !obj->nchildren)
return 0;
if (data->filter(obj, data->flags))
return 0;
if (data->names && data->count < data->maxnames &&
VIR_STRDUP(data->names[data->count], obj->def->name) < 0) {
data->error = true;
return 0;
}
data->count++;
return 0;
}
int
virDomainSnapshotObjListGetNames(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr from,
char **const names,
int maxnames,
unsigned int flags)
{
struct virDomainMomentNameData data = { names, maxnames, flags, 0,
false, virDomainSnapshotFilter };
size_t i;
if (!from) {
/* LIST_ROOTS and LIST_DESCENDANTS have the same bit value,
* but opposite semantics. Toggle here to get the correct
* traversal on the metaroot. */
flags ^= VIR_DOMAIN_SNAPSHOT_LIST_ROOTS;
from = &snapshots->metaroot;
}
/* We handle LIST_ROOT/LIST_DESCENDANTS and LIST_TOPOLOGICAL directly,
* mask those bits out to determine when we must use the filter callback. */
data.flags &= ~(VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS |
VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL);
/* If this common code is being used, we assume that all snapshots
* have metadata, and thus can handle METADATA up front as an
* all-or-none filter. XXX This might not always be true, if we
* add the ability to track qcow2 internal snapshots without the
* use of metadata. */
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_METADATA) ==
VIR_DOMAIN_SNAPSHOT_LIST_NO_METADATA)
return 0;
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_METADATA;
/* For ease of coding the visitor, it is easier to zero each group
* where all of the bits are set. */
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LEAVES;
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_STATUS;
if ((data.flags & VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION) ==
VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION)
data.flags &= ~VIR_DOMAIN_SNAPSHOT_FILTERS_LOCATION;
if (flags & VIR_DOMAIN_SNAPSHOT_LIST_DESCENDANTS) {
/* We could just always do a topological visit; but it is
* possible to optimize for less stack usage and time when a
* simpler full hashtable visit or counter will do. */
if (from->def || (names &&
(flags & VIR_DOMAIN_SNAPSHOT_LIST_TOPOLOGICAL)))
virDomainMomentForEachDescendant(from,
virDomainMomentObjListCopyNames,
&data);
else if (names || data.flags)
virHashForEach(snapshots->objs, virDomainMomentObjListCopyNames,
&data);
else
data.count = virHashSize(snapshots->objs);
} else if (names || data.flags) {
virDomainMomentForEachChild(from,
virDomainMomentObjListCopyNames, &data);
} else {
data.count = from->nchildren;
}
if (data.error) {
for (i = 0; i < data.count; i++)
VIR_FREE(names[i]);
return -1;
}
return data.count;
}
int
virDomainSnapshotObjListNum(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr from,
unsigned int flags)
{
return virDomainSnapshotObjListGetNames(snapshots, from, NULL, 0, flags);
}
virDomainMomentObjPtr
virDomainSnapshotFindByName(virDomainSnapshotObjListPtr snapshots,
const char *name)
{
return name ? virHashLookup(snapshots->objs, name) : &snapshots->metaroot;
}
/* Return the number of objects currently in the list */
int
virDomainSnapshotObjListSize(virDomainSnapshotObjListPtr snapshots)
{
return virHashSize(snapshots->objs);
}
/* Return the current snapshot, or NULL */
virDomainMomentObjPtr
virDomainSnapshotGetCurrent(virDomainSnapshotObjListPtr snapshots)
{
return snapshots->current;
}
/* Return the current snapshot's name, or NULL */
const char *
virDomainSnapshotGetCurrentName(virDomainSnapshotObjListPtr snapshots)
{
if (snapshots->current)
return snapshots->current->def->name;
return NULL;
}
/* Return true if name matches the current snapshot */
bool
virDomainSnapshotIsCurrentName(virDomainSnapshotObjListPtr snapshots,
const char *name)
{
return snapshots->current && STREQ(snapshots->current->def->name, name);
}
/* Update the current snapshot, using NULL if no current remains */
void
virDomainSnapshotSetCurrent(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr snapshot)
{
snapshots->current = snapshot;
}
/* Remove snapshot from the list; return true if it was current */
bool
virDomainSnapshotObjListRemove(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr snapshot)
{
bool ret = snapshots->current == snapshot;
virHashRemoveEntry(snapshots->objs, snapshot->def->name);
if (ret)
snapshots->current = NULL;
return ret;
}
/* Remove all snapshots tracked in the list */
void
virDomainSnapshotObjListRemoveAll(virDomainSnapshotObjListPtr snapshots)
{
virHashRemoveAll(snapshots->objs);
virDomainMomentDropChildren(&snapshots->metaroot);
}
int
virDomainSnapshotForEach(virDomainSnapshotObjListPtr snapshots,
virHashIterator iter,
void *data)
{
return virHashForEach(snapshots->objs, iter, data);
}
/* Struct and callback function used as a hash table callback; each call
* inspects the pre-existing snapshot->def->parent field, and adjusts
* the snapshot->parent field as well as the parent's child fields to
* wire up the hierarchical relations for the given snapshot. The error
* indicator gets set if a parent is missing or a requested parent would
* cause a circular parent chain. */
struct moment_set_relation {
virDomainSnapshotObjListPtr snapshots;
int err;
};
static int
virDomainMomentSetRelations(void *payload,
const void *name ATTRIBUTE_UNUSED,
void *data)
{
virDomainMomentObjPtr obj = payload;
struct moment_set_relation *curr = data;
virDomainMomentObjPtr tmp;
virDomainMomentObjPtr parent;
parent = virDomainSnapshotFindByName(curr->snapshots, obj->def->parent);
if (!parent) {
curr->err = -1;
parent = &curr->snapshots->metaroot;
VIR_WARN("snapshot %s lacks parent", obj->def->name);
} else {
tmp = parent;
while (tmp && tmp->def) {
if (tmp == obj) {
curr->err = -1;
parent = &curr->snapshots->metaroot;
VIR_WARN("snapshot %s in circular chain", obj->def->name);
break;
}
tmp = tmp->parent;
}
}
virDomainMomentSetParent(obj, parent);
return 0;
}
/* Populate parent link and child count of all snapshots, with all
* assigned defs having relations starting as 0/NULL. Return 0 on
* success, -1 if a parent is missing or if a circular relationship
* was requested. */
int
virDomainSnapshotUpdateRelations(virDomainSnapshotObjListPtr snapshots)
{
struct moment_set_relation act = { snapshots, 0 };
virDomainMomentDropChildren(&snapshots->metaroot);
virHashForEach(snapshots->objs, virDomainMomentSetRelations, &act);
if (act.err)
snapshots->current = NULL;
return act.err;
}
int
virDomainListSnapshots(virDomainSnapshotObjListPtr snapshots,
virDomainMomentObjPtr from,
virDomainPtr dom,
virDomainSnapshotPtr **snaps,
unsigned int flags)
{
int count = virDomainSnapshotObjListNum(snapshots, from, flags);
virDomainSnapshotPtr *list = NULL;
char **names;
int ret = -1;
size_t i;
if (!snaps || count < 0)
return count;
if (VIR_ALLOC_N(names, count) < 0 ||
VIR_ALLOC_N(list, count + 1) < 0)
goto cleanup;
if (virDomainSnapshotObjListGetNames(snapshots, from, names, count,
flags) < 0)
goto cleanup;
for (i = 0; i < count; i++)
if ((list[i] = virGetDomainSnapshot(dom, names[i])) == NULL)
goto cleanup;
ret = count;
*snaps = list;
cleanup:
for (i = 0; i < count; i++)
VIR_FREE(names[i]);
VIR_FREE(names);
if (ret < 0 && list) {
for (i = 0; i < count; i++)
virObjectUnref(list[i]);
VIR_FREE(list);
}
return ret;
}