+ lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+ sizeof(lsm.session.name));
+
+ return lttng_ctl_ask_sessiond(&lsm, NULL);
+}
+
+/*
+ * Create or enable an event with a filter expression.
+ *
+ * Return negative error value on error.
+ * Return size of returned session payload data if OK.
+ */
+int lttng_enable_event_with_filter(struct lttng_handle *handle,
+ struct lttng_event *event, const char *channel_name,
+ const char *filter_expression)
+{
+ struct lttcomm_session_msg lsm;
+ struct filter_parser_ctx *ctx;
+ FILE *fmem;
+ int ret = 0;
+
+ if (!filter_expression) {
+ /*
+ * Fall back to normal event enabling if no filter
+ * specified.
+ */
+ return lttng_enable_event(handle, event, channel_name);
+ }
+
+ /*
+ * Empty filter string will always be rejected by the parser
+ * anyway, so treat this corner-case early to eliminate
+ * lttng_fmemopen error for 0-byte allocation.
+ */
+ if (handle == NULL || filter_expression[0] == '\0') {
+ return -LTTNG_ERR_INVALID;
+ }
+
+ /*
+ * casting const to non-const, as the underlying function will
+ * use it in read-only mode.
+ */
+ fmem = lttng_fmemopen((void *) filter_expression,
+ strlen(filter_expression), "r");
+ if (!fmem) {
+ fprintf(stderr, "Error opening memory as stream\n");
+ return -LTTNG_ERR_FILTER_NOMEM;
+ }
+ ctx = filter_parser_ctx_alloc(fmem);
+ if (!ctx) {
+ fprintf(stderr, "Error allocating parser\n");
+ ret = -LTTNG_ERR_FILTER_NOMEM;
+ goto alloc_error;
+ }
+ ret = filter_parser_ctx_append_ast(ctx);
+ if (ret) {
+ fprintf(stderr, "Parse error\n");
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ ret = filter_visitor_set_parent(ctx);
+ if (ret) {
+ fprintf(stderr, "Set parent error\n");
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ if (print_xml) {
+ ret = filter_visitor_print_xml(ctx, stdout, 0);
+ if (ret) {
+ fflush(stdout);
+ fprintf(stderr, "XML print error\n");
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ }
+
+ dbg_printf("Generating IR... ");
+ fflush(stdout);
+ ret = filter_visitor_ir_generate(ctx);
+ if (ret) {
+ fprintf(stderr, "Generate IR error\n");
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ dbg_printf("done\n");
+
+ dbg_printf("Validating IR... ");
+ fflush(stdout);
+ ret = filter_visitor_ir_check_binary_op_nesting(ctx);
+ if (ret) {
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ dbg_printf("done\n");
+
+ dbg_printf("Generating bytecode... ");
+ fflush(stdout);
+ ret = filter_visitor_bytecode_generate(ctx);
+ if (ret) {
+ fprintf(stderr, "Generate bytecode error\n");
+ ret = -LTTNG_ERR_FILTER_INVAL;
+ goto parse_error;
+ }
+ dbg_printf("done\n");
+ dbg_printf("Size of bytecode generated: %u bytes.\n",
+ bytecode_get_len(&ctx->bytecode->b));
+
+ memset(&lsm, 0, sizeof(lsm));
+
+ lsm.cmd_type = LTTNG_ENABLE_EVENT_WITH_FILTER;
+
+ /* Copy channel name */
+ lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
+ sizeof(lsm.u.enable.channel_name));
+ /* Copy event name */
+ if (event) {
+ memcpy(&lsm.u.enable.event, event, sizeof(lsm.u.enable.event));
+ }
+
+ lsm.u.enable.bytecode_len = sizeof(ctx->bytecode->b)
+ + bytecode_get_len(&ctx->bytecode->b);
+
+ lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+
+ lttng_ctl_copy_string(lsm.session.name, handle->session_name,