+ /* Set number of events and free command header */
+ nb_events = cmd_header->nb_events;
+ if (nb_events > INT_MAX) {
+ ret = -EOVERFLOW;
+ goto end;
+ }
+ free(cmd_header);
+ cmd_header = NULL;
+
+ /*
+ * The buffer that is returned must contain a "flat" version of
+ * the events that are returned. In other words, all pointers
+ * within an lttng_event must point to a location within the returned
+ * buffer so that the user may free everything by simply calling free()
+ * on the returned buffer. This is needed in order to maintain API
+ * compatibility.
+ *
+ * A first pass is performed to compute the size of the buffer that
+ * must be allocated. A second pass is then performed to setup
+ * the returned events so that their members always point within the
+ * buffer.
+ *
+ * The layout of the returned buffer is as follows:
+ * - struct lttng_event[nb_events],
+ * - nb_events times the following:
+ * - struct lttng_event_extended,
+ * - flattened version of userspace_probe_location
+ * - filter_expression
+ * - exclusions
+ * - padding to align to 64-bits
+ */
+ comm_ext_at = reception_buffer +
+ (nb_events * sizeof(struct lttng_event));
+ storage_req = nb_events * sizeof(struct lttng_event);
+
+ for (i = 0; i < nb_events; i++) {
+ struct lttcomm_event_extended_header *ext_comm =
+ (struct lttcomm_event_extended_header *) comm_ext_at;
+ int probe_storage_req = 0;
+
+ comm_ext_at += sizeof(*ext_comm);
+ comm_ext_at += ext_comm->filter_len;
+ comm_ext_at +=
+ ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+
+ if (ext_comm->userspace_probe_location_len) {
+ struct lttng_userspace_probe_location *probe_location = NULL;
+ struct lttng_buffer_view probe_location_view;
+
+ probe_location_view = lttng_buffer_view_init(
+ comm_ext_at, 0,
+ ext_comm->userspace_probe_location_len);
+
+ /*
+ * Create a temporary userspace probe location to
+ * determine the size needed by a "flattened" version
+ * of that same probe location.
+ */
+ ret = lttng_userspace_probe_location_create_from_buffer(
+ &probe_location_view, &probe_location);
+ if (ret < 0) {
+ ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto end;
+ }
+
+ ret = lttng_userspace_probe_location_flatten(
+ probe_location, NULL);
+ lttng_userspace_probe_location_destroy(probe_location);
+ if (ret < 0) {
+ ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto end;
+ }
+
+ probe_storage_req = ret;
+ comm_ext_at += ext_comm->userspace_probe_location_len;
+ ret = 0;
+ }
+
+ storage_req += sizeof(struct lttng_event_extended);
+ storage_req += ext_comm->filter_len;
+ storage_req += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+ /* Padding to ensure the flat probe is aligned. */
+ storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
+ storage_req += probe_storage_req;
+ }
+
+ lttng_dynamic_buffer_init(&listing);
+ /*
+ * We must ensure that "listing" is never resized so as to preserve
+ * the validity of the flattened objects.
+ */
+ ret = lttng_dynamic_buffer_set_capacity(&listing, storage_req);
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ goto end;
+ }
+
+ ret = lttng_dynamic_buffer_append(&listing, reception_buffer,
+ nb_events * sizeof(struct lttng_event));
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ goto free_dynamic_buffer;
+ }
+
+ comm_ext_at = reception_buffer +
+ (nb_events * sizeof(struct lttng_event));
+ for (i = 0; i < nb_events; i++) {
+ struct lttng_event *event = (struct lttng_event *)
+ (listing.data + (sizeof(struct lttng_event) * i));
+ struct lttcomm_event_extended_header *ext_comm =
+ (struct lttcomm_event_extended_header *) comm_ext_at;
+ struct lttng_event_extended *event_extended =
+ (struct lttng_event_extended *)
+ (listing.data + listing.size);
+
+ /* Insert struct lttng_event_extended. */
+ ret = lttng_dynamic_buffer_set_size(&listing,
+ listing.size + sizeof(*event_extended));
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ goto free_dynamic_buffer;
+ }
+ event->extended.ptr = event_extended;
+
+ comm_ext_at += sizeof(*ext_comm);
+
+ /* Insert filter expression. */
+ if (ext_comm->filter_len) {
+ event_extended->filter_expression = listing.data +
+ listing.size;
+ ret = lttng_dynamic_buffer_append(&listing, comm_ext_at,
+ ext_comm->filter_len);
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ goto free_dynamic_buffer;
+ }
+ comm_ext_at += ext_comm->filter_len;
+ }
+
+ /* Insert exclusions. */
+ if (ext_comm->nb_exclusions) {
+ event_extended->exclusions.count =
+ ext_comm->nb_exclusions;
+ event_extended->exclusions.strings =
+ listing.data + listing.size;
+
+ ret = lttng_dynamic_buffer_append(&listing,
+ comm_ext_at,
+ ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ }
+ comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+ }
+
+ /* Insert padding to align to 64-bits. */
+ ret = lttng_dynamic_buffer_set_size(&listing,
+ ALIGN_TO(listing.size, sizeof(uint64_t)));
+ if (ret) {
+ ret = -LTTNG_ERR_NOMEM;
+ goto free_dynamic_buffer;
+ }
+
+ /* Insert flattened userspace probe location. */
+ if (ext_comm->userspace_probe_location_len) {
+ struct lttng_userspace_probe_location *probe_location = NULL;
+ struct lttng_buffer_view probe_location_view;
+
+ probe_location_view = lttng_buffer_view_init(
+ comm_ext_at, 0,
+ ext_comm->userspace_probe_location_len);
+
+ ret = lttng_userspace_probe_location_create_from_buffer(
+ &probe_location_view, &probe_location);
+ if (ret < 0) {
+ ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto free_dynamic_buffer;
+ }
+
+ event_extended->probe_location = (struct lttng_userspace_probe_location *)
+ (listing.data + listing.size);
+ ret = lttng_userspace_probe_location_flatten(
+ probe_location, &listing);
+ lttng_userspace_probe_location_destroy(probe_location);
+ if (ret < 0) {
+ ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto free_dynamic_buffer;
+ }
+
+ comm_ext_at += ext_comm->userspace_probe_location_len;
+ }
+ }
+
+ /* Don't reset listing buffer as we return its content. */
+ *events = (struct lttng_event *) listing.data;
+ lttng_dynamic_buffer_init(&listing);
+ ret = (int) nb_events;
+free_dynamic_buffer:
+ lttng_dynamic_buffer_reset(&listing);
+end:
+ free(cmd_header);
+ free(reception_buffer);
+ return ret;