+ } else {
+ /*
+ * HACK: Set the channel's subdomain (JUL, Log4j, Python, etc.)
+ * based on the default name.
+ */
+ if (!strcmp(attr->name, DEFAULT_JUL_CHANNEL_NAME)) {
+ domain = LTTNG_DOMAIN_JUL;
+ } else if (!strcmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME)) {
+ domain = LTTNG_DOMAIN_LOG4J;
+ } else if (!strcmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME)) {
+ domain = LTTNG_DOMAIN_PYTHON;
+ }
+ }
+
+ /*
+ * Set the overwrite mode for this channel based on the session
+ * type unless the client explicitly overrides the channel mode.
+ */
+ if (attr->attr.overwrite == DEFAULT_CHANNEL_OVERWRITE) {
+ attr->attr.overwrite = !!usess->snapshot_mode;
+ }
+
+ /* Enforce mmap output for snapshot sessions. */
+ if (usess->snapshot_mode) {
+ attr->attr.output = LTTNG_EVENT_MMAP;
+ }
+
+ /* Validate common channel properties. */
+ if (channel_validate(attr) < 0) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ /*
+ * Validate UST buffer size and number of buffers: must both be power of 2
+ * and nonzero. We validate right here for UST, because applications will
+ * not report the error to the user (unlike kernel tracing).
+ */
+ if (!attr->attr.subbuf_size ||
+ (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;