+static int lv_init_instance(size_t i, plugin_read_cb callback) {
+ struct lv_user_data *lv_ud = &(lv_read_user_data[i]);
+ struct lv_read_instance *inst = &(lv_ud->inst);
+
+ memset(lv_ud, 0, sizeof(*lv_ud));
+
+ ssnprintf(inst->tag, sizeof(inst->tag), "%s-%zu", PLUGIN_NAME, i);
+ inst->id = i;
+
+ user_data_t *ud = &(lv_ud->ud);
+ ud->data = inst;
+ ud->free_func = NULL;
+
+ INFO(PLUGIN_NAME " plugin: reader %s initialized", inst->tag);
+ return plugin_register_complex_read(NULL, inst->tag, callback, 0, ud);
+}
+
+static void lv_clean_read_state(struct lv_read_state *state) {
+ free_block_devices(state);
+ free_interface_devices(state);
+ free_domains(state);
+}
+
+static void lv_fini_instance(size_t i) {
+ struct lv_read_instance *inst = &(lv_read_user_data[i].inst);
+ struct lv_read_state *state = &(inst->read_state);
+
+ lv_clean_read_state(state);
+ INFO(PLUGIN_NAME " plugin: reader %s finalized", inst->tag);
+}
+
+static int lv_init(void) {
+ if (virInitialize() != 0)
+ return -1;
+
+ if (lv_connect() != 0)
+ return -1;
+
+ DEBUG(PLUGIN_NAME " plugin: starting %i instances", nr_instances);
+
+ for (int i = 0; i < nr_instances; ++i)
+ lv_init_instance(i, lv_read);
+
+ return 0;
+}
+
+/*
+ * returns 0 on success and <0 on error
+ */
+static int lv_domain_get_tag(xmlXPathContextPtr xpath_ctx, const char *dom_name,
+ char *dom_tag) {
+ char xpath_str[BUFFER_MAX_LEN] = {'\0'};
+ xmlXPathObjectPtr xpath_obj = NULL;
+ xmlNodePtr xml_node = NULL;
+ int ret = -1;
+ int err;
+
+ err = xmlXPathRegisterNs(xpath_ctx,
+ (const xmlChar *)METADATA_VM_PARTITION_PREFIX,
+ (const xmlChar *)METADATA_VM_PARTITION_URI);
+ if (err) {
+ ERROR(PLUGIN_NAME " plugin: xmlXpathRegisterNs(%s, %s) failed on domain %s",
+ METADATA_VM_PARTITION_PREFIX, METADATA_VM_PARTITION_URI, dom_name);
+ goto done;
+ }
+
+ ssnprintf(xpath_str, sizeof(xpath_str), "/domain/metadata/%s:%s/text()",
+ METADATA_VM_PARTITION_PREFIX, METADATA_VM_PARTITION_ELEMENT);
+ xpath_obj = xmlXPathEvalExpression((xmlChar *)xpath_str, xpath_ctx);
+ if (xpath_obj == NULL) {
+ ERROR(PLUGIN_NAME " plugin: xmlXPathEval(%s) failed on domain %s",
+ xpath_str, dom_name);
+ goto done;
+ }
+
+ if (xpath_obj->type != XPATH_NODESET) {
+ ERROR(PLUGIN_NAME " plugin: xmlXPathEval(%s) unexpected return type %d "
+ "(wanted %d) on domain %s",
+ xpath_str, xpath_obj->type, XPATH_NODESET, dom_name);
+ goto done;
+ }
+
+ /*
+ * from now on there is no real error, it's ok if a domain
+ * doesn't have the metadata partition tag.
+ */
+ ret = 0;
+ if (xpath_obj->nodesetval == NULL || xpath_obj->nodesetval->nodeNr != 1) {
+ DEBUG(PLUGIN_NAME " plugin: xmlXPathEval(%s) return nodeset size=%i "
+ "expected=1 on domain %s",
+ xpath_str,
+ (xpath_obj->nodesetval == NULL) ? 0 : xpath_obj->nodesetval->nodeNr,
+ dom_name);
+ } else {
+ xml_node = xpath_obj->nodesetval->nodeTab[0];
+ sstrncpy(dom_tag, (const char *)xml_node->content, PARTITION_TAG_MAX_LEN);
+ }
+
+done:
+ /* deregister to clean up */
+ err = xmlXPathRegisterNs(xpath_ctx,
+ (const xmlChar *)METADATA_VM_PARTITION_PREFIX, NULL);
+ if (err) {
+ /* we can't really recover here */
+ ERROR(PLUGIN_NAME
+ " plugin: deregistration of namespace %s failed for domain %s",
+ METADATA_VM_PARTITION_PREFIX, dom_name);
+ }
+ if (xpath_obj)
+ xmlXPathFreeObject(xpath_obj);
+
+ return ret;
+}
+
+static int is_known_tag(const char *dom_tag) {
+ for (int i = 0; i < nr_instances; ++i)
+ if (!strcmp(dom_tag, lv_read_user_data[i].inst.tag))
+ return 1;
+ return 0;
+}
+
+static int lv_instance_include_domain(struct lv_read_instance *inst,
+ const char *dom_name,
+ const char *dom_tag) {
+ if ((dom_tag[0] != '\0') && (strcmp(dom_tag, inst->tag) == 0))
+ return 1;
+
+ /* instance#0 will always be there, so it is in charge of extra duties */
+ if (inst->id == 0) {
+ if (dom_tag[0] == '\0' || !is_known_tag(dom_tag)) {
+ DEBUG(PLUGIN_NAME " plugin#%s: refreshing domain %s "
+ "with unknown tag '%s'",
+ inst->tag, dom_name, dom_tag);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+static int refresh_lists(struct lv_read_instance *inst) {
+ struct lv_read_state *state = &inst->read_state;