fix memory issues

Author: Frefreak

plugins/out_opentelemetry/opentelemetry.c

@@ -709,11 +709,11 @@ static int flush_to_otel(struct opentelemetry_context *ctx,
     Opentelemetry__Proto__Logs__V1__ScopeLogs *scope_logs[1];
     Opentelemetry__Proto__Common__V1__KeyValue **attributes_list;
     Opentelemetry__Proto__Common__V1__KeyValue *attributes;
-    size_t kv_size;
+    size_t kv_size = 0;
     size_t kv_index;
+    size_t index;
     struct mk_list *kv_head;
     struct flb_kv *kv;
-    int index;
 
     void *body;
     unsigned len;
@@ -732,36 +732,48 @@ static int flush_to_otel(struct opentelemetry_context *ctx,
     resource_logs[0] = &resource_log;
 
     kv_size = mk_list_size(&(ctx->kv_labels));
-    attributes_list = flb_calloc(kv_size, sizeof(Opentelemetry__Proto__Common__V1__KeyValue *));
-    if (attributes_list == NULL) {
+    if (kv_size > 0) {
+        attributes_list = flb_calloc(kv_size, sizeof(Opentelemetry__Proto__Common__V1__KeyValue *));
+        if (attributes_list == NULL) {
             flb_errno();
             return -1;
-    }
-    attributes = flb_calloc(kv_size, sizeof(Opentelemetry__Proto__Common__V1__KeyValue));
-    if (attributes == NULL) {
+        }
+        attributes = flb_calloc(kv_size, sizeof(Opentelemetry__Proto__Common__V1__KeyValue));
+        if (attributes == NULL) {
             flb_errno();
+            flb_free(attributes_list);
             return -1;
+        }
+        kv_index = 0;
+        mk_list_foreach(kv_head, &ctx->kv_labels) {
+            kv = mk_list_entry(kv_head, struct flb_kv, _head);
+            opentelemetry__proto__common__v1__key_value__init(&attributes[kv_index]);
+            attributes[kv_index].key = kv->key;
+            attributes[kv_index].value = otlp_any_value_initialize(MSGPACK_OBJECT_STR, 0);
+            if (attributes[kv_index].value == NULL) {
+                flb_errno();
+                // cleanup previous allocated values
+                for (index = 0; index < kv_index; index++) {
+                    flb_free(attributes[index].value);
+                }
+                flb_free(attributes);
+                flb_free(attributes_list);
+                return -1;
+            }
+            attributes[kv_index].value->string_value = kv->val;
+            attributes_list[kv_index] = &attributes[kv_index];
+            kv_index++;
+        }
+        resource_log.resource = flb_calloc(1, sizeof(Opentelemetry__Proto__Resource__V1__Resource));
+        if (resource_log.resource == NULL) {
+            flb_errno();
+            res = -1;
+            goto calloc_resource_fail;
+        }
+        opentelemetry__proto__resource__v1__resource__init(resource_log.resource);
+        resource_log.resource->n_attributes = kv_size;
+        resource_log.resource->attributes = attributes_list;
     }
-    for(index = 0; index < kv_size; index++) {
-            attributes_list[index] = &attributes[index];
-    }
-
-
-    kv_index = 0;
-    mk_list_foreach(kv_head, &ctx->kv_labels) {
-        kv = mk_list_entry(kv_head, struct flb_kv, _head);
-        opentelemetry__proto__common__v1__key_value__init(&attributes[kv_index]);
-        attributes[kv_index].key = kv->key;
-        attributes[kv_index].value = otlp_any_value_initialize(MSGPACK_OBJECT_STR, 0);
-	attributes[kv_index].value->string_value = kv->val;
-        kv_index++;
-    }
-
-    resource_log.resource = flb_calloc(1, sizeof(Opentelemetry__Proto__Resource__V1__Resource));
-    opentelemetry__proto__resource__v1__resource__init(resource_log.resource);
-    resource_log.resource->n_attributes = kv_size;
-    resource_log.resource->attributes = attributes_list;
-
     export_logs.resource_logs = resource_logs;
     export_logs.n_resource_logs = 1;
 
@@ -781,12 +793,15 @@ static int flush_to_otel(struct opentelemetry_context *ctx,
                     ctx->logs_uri);
 
     flb_free(body);
-    flb_free(resource_log.resource);
+calloc_resource_fail:
     for (index = 0; index < kv_size; index++) {
         flb_free(attributes[index].value);
     }
-    flb_free(attributes);
-    flb_free(attributes_list);
+    if (kv_size > 0) {
+        flb_free(resource_log.resource);
+        flb_free(attributes);
+        flb_free(attributes_list);
+    }
 
     return res;
 }