Re: [libvirt] [PATCH v9 04/13] backup: Parse and output checkpoint XML

Add a new file checkpoint_conf.c that performs the translation to and from new XML describing a checkpoint. The code shares a common base class with snapshots, since a checkpoint similarly represents the domain state at a moment in time. Add some basic testing of round trip XML handling through the new code. Of note - this code intentionally differs from snapshots in that XML schema validation is unconditional, rather than based on a public API flag. Also, the redefine flag requires the <domain> sub-element to be present, rather than catering to historical back-compat to older versions. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; ---

diff --git a/src/conf/checkpoint_conf.c b/src/conf/checkpoint_conf.c new file mode 100644 index 0000000000..d50d63ac0e --- /dev/null +++ b/src/conf/checkpoint_conf.c @@ -0,0 +1,576 @@

+static int +virDomainCheckpointDiskDefParseXML(xmlNodePtr node, + xmlXPathContextPtr ctxt, + virDomainCheckpointDiskDefPtr def) +{ + int ret = -1; + char *checkpoint = NULL; + char *bitmap = NULL; + xmlNodePtr saved = ctxt->node; + + ctxt->node = node; + + def->name = virXMLPropString(node, "name"); + if (!def->name) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing name from disk checkpoint element"));

+ goto cleanup; + } + + checkpoint = virXMLPropString(node, "checkpoint");

+ if (checkpoint) { + def->type = virDomainCheckpointTypeFromString(checkpoint); + if (def->type <= 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("unknown disk checkpoint setting '%s'"), + checkpoint);

+ goto cleanup; + } + } else { + def->type = VIR_DOMAIN_CHECKPOINT_TYPE_BITMAP;

+ } + + bitmap = virXMLPropString(node, "bitmap"); + if (bitmap) { + if (def->type != VIR_DOMAIN_CHECKPOINT_TYPE_BITMAP) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("disk checkpoint bitmap '%s' requires " + "type='bitmap'"), + bitmap);

+ goto cleanup; + } + VIR_STEAL_PTR(def->bitmap, bitmap); + } + + ret = 0; + cleanup: + ctxt->node = saved; + + VIR_FREE(checkpoint); + VIR_FREE(bitmap); + if (ret < 0) + virDomainCheckpointDiskDefClear(def); + return ret; +} + +/* flags is bitwise-or of virDomainCheckpointParseFlags. If flags + * does not include VIR_DOMAIN_CHECKPOINT_PARSE_REDEFINE, then caps + * and current are ignored. + */ +static virDomainCheckpointDefPtr +virDomainCheckpointDefParse(xmlXPathContextPtr ctxt, + virCapsPtr caps, + virDomainXMLOptionPtr xmlopt, + bool *current, + unsigned int flags) +{ + virDomainCheckpointDefPtr def = NULL; + virDomainCheckpointDefPtr ret = NULL; + xmlNodePtr *nodes = NULL; + size_t i; + int n; + char *creation = NULL; + int active; + char *tmp; + + if (!(def = virDomainCheckpointDefNew())) + return NULL; + + def->parent.name = virXPathString("string(./name)", ctxt); + if (def->parent.name == NULL) { + if (flags & VIR_DOMAIN_CHECKPOINT_PARSE_REDEFINE) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("a redefined checkpoint must have a name")); + goto cleanup; + } + } + + def->parent.description = virXPathString("string(./description)", ctxt); + + if (flags & VIR_DOMAIN_CHECKPOINT_PARSE_REDEFINE) { + if (virXPathLongLong("string(./creationTime)", ctxt, + &def->parent.creationTime) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing creationTime from existing checkpoint")); + goto cleanup;

+ } + + def->parent.parent_name = virXPathString("string(./parent/name)", ctxt); + + if (virXPathInt("string(./current)", ctxt, &active) < 0 || !current) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing current from existing checkpoint")); + goto cleanup; + } + *current = !!active; + + if ((tmp = virXPathString("string(./domain/@type)", ctxt))) { + int domainflags = VIR_DOMAIN_DEF_PARSE_INACTIVE | + VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE; + xmlNodePtr domainNode = virXPathNode("./domain", ctxt); + + VIR_FREE(tmp); + if (!domainNode) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing domain in checkpoint")); + goto cleanup; + } + def->parent.dom = virDomainDefParseNode(ctxt->node->doc, domainNode, + caps, xmlopt, NULL, + domainflags); + if (!def->parent.dom) + goto cleanup; + } else { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing domain in checkpoint redefine")); + goto cleanup; + } + } else if (virDomainXMLOptionRunMomentPostParse(xmlopt, &def->parent) < 0) { + goto cleanup; + } + + if ((n = virXPathNodeSet("./disks/*", ctxt, &nodes)) < 0) + goto cleanup; + if (n && VIR_ALLOC_N(def->disks, n) < 0) + goto cleanup; + def->ndisks = n; + for (i = 0; i < def->ndisks; i++) { + if (virDomainCheckpointDiskDefParseXML(nodes[i], ctxt, + &def->disks[i]) < 0) + goto cleanup; + } + + VIR_STEAL_PTR(ret, def); + + cleanup: + VIR_FREE(creation); + VIR_FREE(nodes); + virObjectUnref(def); + + return ret; +} + +static virDomainCheckpointDefPtr +virDomainCheckpointDefParseNode(xmlDocPtr xml, + xmlNodePtr root, + virCapsPtr caps, + virDomainXMLOptionPtr xmlopt, + bool *current, + unsigned int flags) +{ + xmlXPathContextPtr ctxt = NULL; + virDomainCheckpointDefPtr def = NULL; + VIR_AUTOFREE(char *) schema = NULL; + + if (!virXMLNodeNameEqual(root, "domaincheckpoint")) { + virReportError(VIR_ERR_XML_ERROR, "%s", _("domaincheckpoint")); + goto cleanup;

+ } + + /* This is a new enough API to make schema validation unconditional */ + schema = virFileFindResource("domaincheckpoint.rng", + abs_top_srcdir "/docs/schemas", + PKGDATADIR "/schemas"); + if (!schema) + return NULL; + if (virXMLValidateAgainstSchema(schema, xml) < 0) + return NULL; + + ctxt = xmlXPathNewContext(xml); + if (ctxt == NULL) { + virReportOOMError(); + goto cleanup; + } + + ctxt->node = root; + def = virDomainCheckpointDefParse(ctxt, caps, xmlopt, current, flags); + cleanup: + xmlXPathFreeContext(ctxt); + return def; +}

+int +virDomainCheckpointAlignDisks(virDomainCheckpointDefPtr def) +{ + int ret = -1; + virBitmapPtr map = NULL; + size_t i; + int ndisks; + int checkpoint_default = VIR_DOMAIN_CHECKPOINT_TYPE_NONE; + + if (!def->parent.dom) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("missing domain in checkpoint")); + goto cleanup;

+ } + + if (def->ndisks > def->parent.dom->ndisks) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("too many disk checkpoint requests for domain")); + goto cleanup; + } + + /* Unlikely to have a guest without disks but technically possible. */ + if (!def->parent.dom->ndisks) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("domain must have at least one disk to perform " + "checkpoints")); + goto cleanup; + } + + /* If <disks> omitted, do bitmap on all disks; otherwise, do nothing + * for omitted disks */ + if (!def->ndisks) + checkpoint_default = VIR_DOMAIN_CHECKPOINT_TYPE_BITMAP; + + if (!(map = virBitmapNew(def->parent.dom->ndisks))) + goto cleanup; + + /* Double check requested disks. */ + for (i = 0; i < def->ndisks; i++) { + virDomainCheckpointDiskDefPtr disk = &def->disks[i]; + int idx = virDomainDiskIndexByName(def->parent.dom, disk->name, false); + + if (idx < 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("no disk named '%s'"), disk->name); + goto cleanup; + } + + if (virBitmapIsBitSet(map, idx)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("disk '%s' specified twice"), + disk->name); + goto cleanup; + } + ignore_value(virBitmapSetBit(map, idx)); + disk->idx = idx; + + if (STRNEQ(disk->name, def->parent.dom->disks[idx]->dst)) { + VIR_FREE(disk->name); + if (VIR_STRDUP(disk->name, def->parent.dom->disks[idx]->dst) < 0) + goto cleanup; + } + } + + /* Provide defaults for all remaining disks. */ + ndisks = def->ndisks; + if (VIR_EXPAND_N(def->disks, def->ndisks, + def->parent.dom->ndisks - def->ndisks) < 0) + goto cleanup; + + for (i = 0; i < def->parent.dom->ndisks; i++) { + virDomainCheckpointDiskDefPtr disk; + + if (virBitmapIsBitSet(map, i)) + continue; + disk = &def->disks[ndisks++]; + if (VIR_STRDUP(disk->name, def->parent.dom->disks[i]->dst) < 0) + goto cleanup; + disk->idx = i; + + /* Don't checkpoint empty drives */

+ if (virStorageSourceIsEmpty(def->parent.dom->disks[i]->src)) + disk->type = VIR_DOMAIN_CHECKPOINT_TYPE_NONE; + else + disk->type = checkpoint_default; + } + + qsort(&def->disks[0], def->ndisks, sizeof(def->disks[0]), + virDomainCheckpointCompareDiskIndex); + + /* Generate default bitmap names for checkpoint */ + if (virDomainCheckpointDefAssignBitmapNames(def) < 0) + goto cleanup; + + ret = 0; + + cleanup: + virBitmapFree(map); + return ret; +}

+static int +virDomainCheckpointDiskDefFormat(virBufferPtr buf, + virDomainCheckpointDiskDefPtr disk, + unsigned int flags) +{ + if (!disk->name) + return 0; + + virBufferEscapeString(buf, "<disk name='%s'", disk->name); + if (disk->type) + virBufferAsprintf(buf, " checkpoint='%s'", + virDomainCheckpointTypeToString(disk->type)); + if (disk->bitmap) { + virBufferEscapeString(buf, " bitmap='%s'", disk->bitmap); + if (flags & VIR_DOMAIN_CHECKPOINT_FORMAT_SIZE) + virBufferAsprintf(buf, " size='%llu'", disk->size);

+ } + virBufferAddLit(buf, "/>\n"); + return 0; +}