+ /*
+ * Setup lttng message with payload size set to the event list size in
+ * bytes and then copy list into the llm payload.
+ */
+ ret = setup_lttng_msg(cmd_ctx, size);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ /* Copy event list into message payload */
+ memcpy(cmd_ctx->llm->payload, event_list, size);
+
+ free(event_list);
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case LTTNG_START_TRACE:
+ {
+ struct ltt_kernel_channel *chan;
+
+ /* Setup lttng message with no payload */
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ /* Kernel tracing */
+ if (cmd_ctx->session->kernel_session != NULL) {
+ if (cmd_ctx->session->kernel_session->metadata == NULL) {
+ DBG("Open kernel metadata");
+ ret = kernel_open_metadata(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_META_FAIL;
+ goto error;
+ }
+ }
+
+ if (cmd_ctx->session->kernel_session->metadata_stream_fd == 0) {
+ DBG("Opening kernel metadata stream");
+ if (cmd_ctx->session->kernel_session->metadata_stream_fd == 0) {
+ ret = kernel_open_metadata_stream(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ERR("Kernel create metadata stream failed");
+ ret = LTTCOMM_KERN_STREAM_FAIL;
+ goto error;
+ }
+ }
+ }
+
+ /* For each channel */
+ cds_list_for_each_entry(chan, &cmd_ctx->session->kernel_session->channel_list.head, list) {
+ if (chan->stream_count == 0) {
+ ret = kernel_open_channel_stream(chan);
+ if (ret < 0) {
+ ERR("Kernel create channel stream failed");
+ ret = LTTCOMM_KERN_STREAM_FAIL;
+ goto error;
+ }
+ /* Update the stream global counter */
+ cmd_ctx->session->kernel_session->stream_count_global += ret;
+ }
+ }
+
+ DBG("Start kernel tracing");
+ ret = kernel_start_session(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ERR("Kernel start session failed");
+ ret = LTTCOMM_KERN_START_FAIL;
+ goto error;
+ }
+
+ ret = start_kernel_trace(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ret = LTTCOMM_KERN_START_FAIL;
+ goto error;
+ }
+
+ /* Quiescent wait after starting trace */
+ kernel_wait_quiescent(kernel_tracer_fd);
+ }
+
+ /* TODO: Start all UST traces */
+
+ ret = LTTCOMM_OK;
+ break;
+ }
+ case LTTNG_STOP_TRACE:
+ {
+ struct ltt_kernel_channel *chan;
+ /* Setup lttng message with no payload */
+ ret = setup_lttng_msg(cmd_ctx, 0);
+ if (ret < 0) {
+ goto setup_error;
+ }
+
+ /* Kernel tracer */
+ if (cmd_ctx->session->kernel_session != NULL) {
+ DBG("Stop kernel tracing");
+
+ ret = kernel_metadata_flush_buffer(cmd_ctx->session->kernel_session->metadata_stream_fd);
+ if (ret < 0) {
+ ERR("Kernel metadata flush failed");
+ }
+
+ cds_list_for_each_entry(chan, &cmd_ctx->session->kernel_session->channel_list.head, list) {
+ ret = kernel_flush_buffer(chan);
+ if (ret < 0) {
+ ERR("Kernel flush buffer error");
+ }
+ }
+
+ ret = kernel_stop_session(cmd_ctx->session->kernel_session);
+ if (ret < 0) {
+ ERR("Kernel stop session failed");
+ ret = LTTCOMM_KERN_STOP_FAIL;
+ goto error;
+ }
+
+ /* Quiescent wait after stopping trace */
+ kernel_wait_quiescent(kernel_tracer_fd);
+ }
+
+ /* TODO : User-space tracer */