Fix: liblttng-ctl comm: lttng_event_field is not packed
[lttng-tools.git] / src / common / event.cpp
index 502ccdcf27423c0467750d0bb26b72ea70df9b64..c3a2c0eb7203566924b0240559f3fe4bbc46a272 100644 (file)
@@ -1278,6 +1278,192 @@ void lttng_event_context_destroy(struct lttng_event_context *context)
        free(context);
 }
 
+/*
+ * This is a specialized populate for lttng_event_field since it ignores
+ * the extension field of the lttng_event struct and simply copies what it can
+ * to the internal struct lttng_event of a lttng_event_field.
+ */
+static void lttng_event_field_populate_lttng_event_from_event(
+               const struct lttng_event *src, struct lttng_event *destination)
+{
+       memcpy(destination, src, sizeof(*destination));
+
+       /* Remove all possible dynamic data from the destination event rule. */
+       destination->extended.ptr = NULL;
+}
+
+ssize_t lttng_event_field_create_from_payload(
+               struct lttng_payload_view *view,
+               struct lttng_event_field **field)
+{
+       ssize_t ret, offset = 0;
+       struct lttng_event_field *local_event_field = NULL;
+       struct lttng_event *event = NULL;
+       const struct lttng_event_field_comm *comm;
+       const char* name = NULL;
+
+       assert(field);
+       assert(view);
+
+       {
+               const struct lttng_buffer_view comm_view =
+                               lttng_buffer_view_from_view(
+                                               &view->buffer, offset,
+                                               sizeof(*comm));
+
+               if (!lttng_buffer_view_is_valid(&comm_view)) {
+                       ret = -1;
+                       goto end;
+               }
+
+               /* lttng_event_field_comm header */
+               comm = (const lttng_event_field_comm *) comm_view.data;
+               offset += sizeof(*comm);
+       }
+
+       local_event_field = (struct lttng_event_field *)
+                       zmalloc(sizeof(*local_event_field));
+       if (!local_event_field) {
+               ret = -1;
+               goto end;
+       }
+
+       local_event_field->type = (lttng_event_field_type) comm->type;
+       local_event_field->nowrite = comm->nowrite;
+
+       /* Field name */
+       {
+               const struct lttng_buffer_view name_view =
+                               lttng_buffer_view_from_view(
+                                               &view->buffer, offset,
+                                               comm->name_len);
+
+               if (!lttng_buffer_view_is_valid(&name_view)) {
+                       ret = -1;
+                       goto end;
+               }
+
+               name = name_view.data;
+
+               if (!lttng_buffer_view_contains_string(&name_view,
+                               name_view.data, comm->name_len)) {
+                       ret = -1;
+                       goto end;
+               }
+
+               if (comm->name_len > LTTNG_SYMBOL_NAME_LEN - 1) {
+                       /* Name is too long.*/
+                       ret = -1;
+                       goto end;
+               }
+
+               offset += comm->name_len;
+       }
+
+       /* Event */
+       {
+               struct lttng_payload_view event_view =
+                               lttng_payload_view_from_view(
+                                               view, offset,
+                                               comm->event_len);
+
+               if (!lttng_payload_view_is_valid(&event_view)) {
+                       ret = -1;
+                       goto end;
+               }
+
+               ret = lttng_event_create_from_payload(&event_view, &event, NULL,
+                               NULL, NULL);
+               if (ret != comm->event_len) {
+                       ret = -1;
+                       goto end;
+               }
+
+               offset += ret;
+       }
+
+       assert(name);
+       assert(event);
+
+       if (lttng_strncpy(local_event_field->field_name, name , LTTNG_SYMBOL_NAME_LEN)) {
+               ret = -1;
+               goto end;
+       }
+
+       lttng_event_field_populate_lttng_event_from_event(
+                       event, &local_event_field->event);
+
+       *field = local_event_field;
+       local_event_field = NULL;
+       ret = offset;
+end:
+       lttng_event_destroy(event);
+       free(local_event_field);
+       return ret;
+}
+
+int lttng_event_field_serialize(const struct lttng_event_field *field,
+               struct lttng_payload *payload)
+{
+       int ret;
+       size_t header_offset, size_before_event;
+       size_t name_len;
+       struct lttng_event_field_comm event_field_comm = { 0 };
+       struct lttng_event_field_comm *header;
+
+       assert(field);
+       assert(payload);
+
+       /* Save the header location for later in-place header update. */
+       header_offset = payload->buffer.size;
+
+       name_len = strnlen(field->field_name, LTTNG_SYMBOL_NAME_LEN);
+       if (name_len == LTTNG_SYMBOL_NAME_LEN) {
+               /* Event name is not NULL-terminated. */
+               ret = -1;
+               goto end;
+       }
+
+       /* Add null termination. */
+       name_len += 1;
+
+       event_field_comm.type = field->type;
+       event_field_comm.nowrite = (uint8_t)field->nowrite;
+       event_field_comm.name_len = name_len;
+
+       /* Header */
+       ret = lttng_dynamic_buffer_append(
+                       &payload->buffer, &event_field_comm,
+                       sizeof(event_field_comm));
+       if (ret) {
+               goto end;
+       }
+
+       /* Field name */
+       ret = lttng_dynamic_buffer_append(&payload->buffer, field->field_name,
+                       name_len);
+       if (ret) {
+               goto end;
+       }
+
+       size_before_event = payload->buffer.size;
+       ret = lttng_event_serialize(
+                       &field->event, 0, NULL, NULL, 0, 0, payload);
+       if (ret) {
+               ret = -1;
+               goto end;
+       }
+
+       /* Update the event len. */
+       header = (struct lttng_event_field_comm *)
+                       ((char *) payload->buffer.data +
+                               header_offset);
+       header->event_len = payload->buffer.size - size_before_event;
+
+end:
+       return ret;
+}
+
 static enum lttng_error_code compute_flattened_size(
                struct lttng_dynamic_pointer_array *events, size_t *size)
 {
@@ -1595,3 +1781,158 @@ end:
        lttng_dynamic_pointer_array_reset(&local_events);
        return ret;
 }
+
+static enum lttng_error_code flatten_lttng_event_fields(
+               struct lttng_dynamic_pointer_array *event_fields,
+               struct lttng_event_field **flattened_event_fields)
+{
+       int ret, i;
+       enum lttng_error_code ret_code;
+       size_t storage_req = 0;
+       struct lttng_dynamic_buffer local_flattened_event_fields;
+       int nb_event_field;
+
+       assert(event_fields);
+       assert(flattened_event_fields);
+
+       lttng_dynamic_buffer_init(&local_flattened_event_fields);
+       nb_event_field = lttng_dynamic_pointer_array_get_count(event_fields);
+
+       /*
+        * Here even if the event field contains a `struct lttng_event` that
+        * could contain dynamic data, in reality it is not the case.
+        * Dynamic data is not present. Here the flattening is mostly a direct
+        * memcpy. This is less than ideal but this code is still better than
+        * direct usage of an unpacked lttng_event_field array.
+        */
+       storage_req += sizeof(struct lttng_event_field) * nb_event_field;
+
+       lttng_dynamic_buffer_init(&local_flattened_event_fields);
+
+       /*
+        * We must ensure that "local_flattened_event_fields" is never resized
+        * so as to preserve the validity of the flattened objects.
+        */
+       ret = lttng_dynamic_buffer_set_capacity(
+                       &local_flattened_event_fields, storage_req);
+       if (ret) {
+               ret_code = LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       for (i = 0; i < nb_event_field; i++) {
+               const struct lttng_event_field *element =
+                               (const struct lttng_event_field *)
+                                       lttng_dynamic_pointer_array_get_pointer(
+                                               event_fields, i);
+
+               if (!element) {
+                       ret_code = LTTNG_ERR_FATAL;
+                       goto end;
+               }
+               ret = lttng_dynamic_buffer_append(&local_flattened_event_fields,
+                               element, sizeof(struct lttng_event_field));
+               if (ret) {
+                       ret_code = LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+       }
+
+       /* Don't reset local_flattened_channels buffer as we return its content. */
+       *flattened_event_fields = (struct lttng_event_field *) local_flattened_event_fields.data;
+       lttng_dynamic_buffer_init(&local_flattened_event_fields);
+       ret_code = LTTNG_OK;
+end:
+       lttng_dynamic_buffer_reset(&local_flattened_event_fields);
+       return ret_code;
+}
+
+static enum lttng_error_code event_field_list_create_from_payload(
+               struct lttng_payload_view *view,
+               unsigned int count,
+               struct lttng_dynamic_pointer_array **event_field_list)
+{
+       enum lttng_error_code ret_code;
+       int ret, offset = 0;
+       unsigned int i;
+       struct lttng_dynamic_pointer_array *list = NULL;
+
+       assert(view);
+       assert(event_field_list);
+
+       list = (struct lttng_dynamic_pointer_array *) zmalloc(sizeof(*list));
+       if (!list) {
+               ret_code = LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       lttng_dynamic_pointer_array_init(list, free);
+
+       for (i = 0; i < count; i++) {
+               ssize_t event_field_size;
+               struct lttng_event_field *field = NULL;
+               struct lttng_payload_view event_field_view =
+                               lttng_payload_view_from_view(view, offset, -1);
+
+               event_field_size = lttng_event_field_create_from_payload(
+                               &event_field_view, &field);
+               if (event_field_size < 0) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+
+               /* Lifetime and management of the object is now bound to the array. */
+               ret = lttng_dynamic_pointer_array_add_pointer(list, field);
+               if (ret) {
+                       free(field);
+                       ret_code = LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               offset += event_field_size;
+       }
+
+       if (view->buffer.size != offset) {
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
+       }
+
+       *event_field_list = list;
+       list = NULL;
+       ret_code = LTTNG_OK;
+
+end:
+       if (list) {
+               lttng_dynamic_pointer_array_reset(list);
+               free(list);
+       }
+
+       return ret_code;
+}
+
+enum lttng_error_code lttng_event_fields_create_and_flatten_from_payload(
+               struct lttng_payload_view *view,
+               unsigned int count,
+               struct lttng_event_field **fields)
+{
+       enum lttng_error_code ret_code;
+       struct lttng_dynamic_pointer_array *local_event_fields = NULL;
+
+       ret_code = event_field_list_create_from_payload(
+                       view, count, &local_event_fields);
+       if (ret_code != LTTNG_OK) {
+               goto end;
+       }
+
+       ret_code = flatten_lttng_event_fields(local_event_fields, fields);
+       if (ret_code != LTTNG_OK) {
+               goto end;
+       }
+end:
+       if (local_event_fields) {
+               lttng_dynamic_pointer_array_reset(local_event_fields);
+               free(local_event_fields);
+       }
+
+       return ret_code;
+}
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