+/*
+ * Enable event(s) for a channel, possibly with exclusions and a filter.
+ * If no event name is specified, all events are enabled.
+ * If no channel name is specified, the default name is used.
+ * If filter expression is not NULL, the filter is set for the event.
+ * If exclusion count is not zero, the exclusions are set for the event.
+ * Returns size of returned session payload data or a negative error code.
+ */
+int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
+ struct lttng_event *ev, const char *channel_name,
+ const char *original_filter_expression,
+ int exclusion_count, char **exclusion_list)
+{
+ struct lttcomm_session_msg lsm;
+ char *varlen_data;
+ int ret = 0;
+ unsigned int free_filter_expression = 0;
+ struct filter_parser_ctx *ctx = NULL;
+ /*
+ * Cast as non-const since we may replace the filter expression
+ * by a dynamically allocated string. Otherwise, the original
+ * string is not modified.
+ */
+ char *filter_expression = (char *) original_filter_expression;
+
+ if (handle == NULL || ev == NULL) {
+ ret = -LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ /* 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 (filter_expression && filter_expression[0] == '\0') {
+ ret = -LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ memset(&lsm, 0, sizeof(lsm));
+
+ /* If no channel name, send empty string. */
+ if (channel_name == NULL) {
+ lttng_ctl_copy_string(lsm.u.enable.channel_name, "",
+ sizeof(lsm.u.enable.channel_name));
+ } else {
+ lttng_ctl_copy_string(lsm.u.enable.channel_name, channel_name,
+ sizeof(lsm.u.enable.channel_name));
+ }
+
+ if (ev->name[0] != '\0') {
+ lsm.cmd_type = LTTNG_ENABLE_EVENT;
+ } else {
+ lsm.cmd_type = LTTNG_ENABLE_ALL_EVENT;
+ }
+
+ lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
+ memcpy(&lsm.u.enable.event, ev, sizeof(lsm.u.enable.event));
+
+ lttng_ctl_copy_string(lsm.session.name, handle->session_name,
+ sizeof(lsm.session.name));
+ lsm.u.enable.exclusion_count = exclusion_count;
+ lsm.u.enable.bytecode_len = 0;
+
+ /*
+ * For the JUL domain, a filter is enforced except for the enable all
+ * event. This is done to avoid having the event in all sessions thus
+ * filtering by logger name.
+ */
+ if (exclusion_count == 0 && filter_expression == NULL &&
+ (handle->domain.type != LTTNG_DOMAIN_JUL &&
+ handle->domain.type != LTTNG_DOMAIN_LOG4J)) {
+ goto ask_sessiond;
+ }
+
+ /*
+ * We have either a filter or some exclusions, so we need to set up
+ * a variable-length memory block from where to send the data
+ */
+
+ /* Parse filter expression */
+ if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
+ || handle->domain.type == LTTNG_DOMAIN_LOG4J) {
+ if (handle->domain.type == LTTNG_DOMAIN_JUL ||
+ handle->domain.type == LTTNG_DOMAIN_LOG4J) {
+ char *jul_filter;
+
+ /* Setup JUL filter if needed. */
+ jul_filter = set_jul_filter(filter_expression, ev);
+ if (!jul_filter) {
+ if (!filter_expression) {
+ /* No JUL and no filter, just skip everything below. */
+ goto ask_sessiond;
+ }
+ } else {
+ /*
+ * With a JUL filter, the original filter has been added to it
+ * thus replace the filter expression.
+ */
+ filter_expression = jul_filter;
+ free_filter_expression = 1;
+ }
+ }
+
+ ret = generate_filter(filter_expression, &lsm, &ctx);
+ if (ret) {
+ goto filter_error;
+ }