+static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
+ int *sock_error, struct lttng_event *event)
+{
+ int fd, ret;
+ struct lttng_userspace_probe_location *probe_location;
+ struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+ struct lttng_dynamic_buffer probe_location_buffer;
+ struct lttng_buffer_view buffer_view;
+
+ /*
+ * Create a buffer to store the serialized version of the probe
+ * location.
+ */
+ lttng_dynamic_buffer_init(&probe_location_buffer);
+ ret = lttng_dynamic_buffer_set_size(&probe_location_buffer,
+ cmd_ctx->lsm->u.enable.userspace_probe_location_len);
+ if (ret) {
+ ret = LTTNG_ERR_NOMEM;
+ goto error;
+ }
+
+ /*
+ * Receive the probe location.
+ */
+ ret = lttcomm_recv_unix_sock(sock, probe_location_buffer.data,
+ probe_location_buffer.size);
+ if (ret <= 0) {
+ DBG("Nothing recv() from client var len data... continuing");
+ *sock_error = 1;
+ lttng_dynamic_buffer_reset(&probe_location_buffer);
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ buffer_view = lttng_buffer_view_from_dynamic_buffer(
+ &probe_location_buffer, 0, probe_location_buffer.size);
+
+ /*
+ * Extract the probe location from the serialized version.
+ */
+ ret = lttng_userspace_probe_location_create_from_buffer(
+ &buffer_view, &probe_location);
+ if (ret < 0) {
+ WARN("Failed to create a userspace probe location from the received buffer");
+ lttng_dynamic_buffer_reset( &probe_location_buffer);
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ /*
+ * Receive the file descriptor to the target binary from the client.
+ */
+ DBG("Receiving userspace probe target FD from client ...");
+ ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
+ if (ret <= 0) {
+ DBG("Nothing recv() from client userspace probe fd... continuing");
+ *sock_error = 1;
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ /*
+ * Set the file descriptor received from the client through the unix
+ * socket in the probe location.
+ */
+ lookup = lttng_userspace_probe_location_get_lookup_method(probe_location);
+ if (!lookup) {
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ /*
+ * From the kernel tracer's perspective, all userspace probe event types
+ * are all the same: a file and an offset.
+ */
+ switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+ case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+ ret = lttng_userspace_probe_location_function_set_binary_fd(
+ probe_location, fd);
+ break;
+ case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+ ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
+ probe_location, fd);
+ break;
+ default:
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ if (ret) {
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ /* Attach the probe location to the event. */
+ ret = lttng_event_set_userspace_probe_location(event, probe_location);
+ if (ret) {
+ ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+ goto error;
+ }
+
+ lttng_dynamic_buffer_reset(&probe_location_buffer);
+error:
+ return ret;
+}
+
+/*
+ * Check if the current kernel tracer supports the session rotation feature.
+ * Return 1 if it does, 0 otherwise.
+ */
+static int check_rotate_compatible(void)
+{
+ int ret = 1;
+
+ if (kernel_tracer_version.major != 2 || kernel_tracer_version.minor < 11) {
+ DBG("Kernel tracer version is not compatible with the rotation feature");
+ ret = 0;
+ }
+
+ return ret;
+}
+