status != LTTNG_LIVE_ITERATOR_STATUS_END) {
goto end;
}
- for (trace_idx = 0; trace_idx < session->traces->len; trace_idx++) {
+ trace_idx = 0;
+ while (trace_idx < session->traces->len) {
struct lttng_live_trace *trace =
g_ptr_array_index(session->traces, trace_idx);
status = lttng_live_metadata_update(trace);
- if (status != LTTNG_LIVE_ITERATOR_STATUS_OK &&
- status != LTTNG_LIVE_ITERATOR_STATUS_END) {
+ switch (status) {
+ case LTTNG_LIVE_ITERATOR_STATUS_OK:
+ trace_idx++;
+ break;
+ case LTTNG_LIVE_ITERATOR_STATUS_END:
+ /*
+ * The trace has ended. Remove it of the array an
+ * continue the iteration.
+ * We can remove the trace safely when using the
+ * g_ptr_array_remove_index_fast because it replaces
+ * the element at trace_idx with the array's last
+ * element. trace_idx is not incremented because of
+ * that.
+ */
+ (void) g_ptr_array_remove_index_fast(session->traces,
+ trace_idx);
+ break;
+ default:
goto end;
}
}
uint64_t stream_id;
/* Weak reference. */
struct ctf_metadata_decoder *decoder;
-
- bool closed;
};
struct lttng_live_trace {
const char *hostname,
const char *session_name);
-ssize_t lttng_live_get_one_metadata_packet(struct lttng_live_trace *trace,
- FILE *fp);
+enum lttng_live_get_one_metadata_status {
+ /* The end of the metadata stream was reached. */
+ LTTNG_LIVE_GET_ONE_METADATA_STATUS_END = 1,
+ /* One metadata packet was received and written to file. */
+ LTTNG_LIVE_GET_ONE_METADATA_STATUS_OK = 0,
+ /* The metadata stream was not found on the relay. */
+ LTTNG_LIVE_GET_ONE_METADATA_STATUS_CLOSED = -1,
+ /*
+ * A critical error occurred when contacting the relay or while
+ * handling its response.
+ */
+ LTTNG_LIVE_GET_ONE_METADATA_STATUS_ERROR = -2,
+};
+
+/*
+ * lttng_live_get_one_metadata_packet() asks the Relay Daemon for new metadata.
+ * If new metadata is received, the function writes it to the provided file
+ * handle and updates the reply_len output parameter. This function should be
+ * called in loop until _END status is received to ensure all metadata is
+ * written to the file.
+ */
+enum lttng_live_get_one_metadata_status lttng_live_get_one_metadata_packet(
+ struct lttng_live_trace *trace, FILE *fp, size_t *reply_len);
+
enum lttng_live_iterator_status lttng_live_get_next_index(
struct lttng_live_msg_iter *lttng_live_msg_iter,
struct lttng_live_stream_iterator *stream,
{
struct lttng_live_session *session = trace->session;
struct lttng_live_metadata *metadata = trace->metadata;
- ssize_t ret = 0;
size_t size, len_read = 0;
char *metadata_buf = NULL;
+ bool keep_receiving;
FILE *fp = NULL;
enum ctf_metadata_decoder_status decoder_status;
enum lttng_live_iterator_status status =
LTTNG_LIVE_ITERATOR_STATUS_OK;
bt_logging_level log_level = trace->log_level;
bt_self_component *self_comp = trace->self_comp;
+ enum lttng_live_get_one_metadata_status metadata_status;
/* No metadata stream yet. */
if (!metadata) {
goto error;
}
+ keep_receiving = true;
/* Grab all available metadata. */
- do {
+ while (keep_receiving) {
+ size_t reply_len = 0;
/*
- * get_one_metadata_packet returns the number of bytes
- * received, 0 when we have received everything, a
- * negative value on error.
+ * lttng_live_get_one_metadata_packet() asks the Relay Daemon
+ * for new metadata. If new metadata is received, the function
+ * writes it to the provided file handle and updates the
+ * reply_len output parameter. We call this function in loop
+ * until it returns _END meaning that no new metadata is
+ * available.
+ * We may receive a _CLOSED status if the metadata stream we
+ * are requesting is no longer available on the relay.
+ * If we receive an _ERROR status, it means there was a
+ * networking, allocating, or some other unrecoverable error.
*/
- ret = lttng_live_get_one_metadata_packet(trace, fp);
- if (ret > 0) {
- len_read += ret;
+ metadata_status = lttng_live_get_one_metadata_packet(trace, fp,
+ &reply_len);
+
+ switch (metadata_status) {
+ case LTTNG_LIVE_GET_ONE_METADATA_STATUS_OK:
+ len_read += reply_len;
+ break;
+ case LTTNG_LIVE_GET_ONE_METADATA_STATUS_END:
+ keep_receiving = false;
+ break;
+ case LTTNG_LIVE_GET_ONE_METADATA_STATUS_CLOSED:
+ keep_receiving = false;
+ break;
+ case LTTNG_LIVE_GET_ONE_METADATA_STATUS_ERROR:
+ goto error;
+ default:
+ abort();
}
- } while (ret > 0);
+ }
/*
- * Consider metadata closed as soon as we get an error reading
- * it (e.g. cannot be found).
+ * A closed metadata stream means the trace is no longer active. Return
+ * _END so that the caller can remove the trace from its list.
*/
- if (ret < 0) {
- if (!metadata->closed) {
- metadata->closed = true;
- /*
- * Release our reference on the trace as soon as
- * we know the metadata stream is not available
- * anymore. This won't necessarily teardown the
- * metadata objects immediately, but only when
- * the data streams are done.
- */
- metadata->trace = NULL;
- }
- if (errno == EINTR) {
- if (lttng_live_graph_is_canceled(
- session->lttng_live_msg_iter)) {
- status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
- goto end;
- }
- }
+ if (metadata_status == LTTNG_LIVE_GET_ONE_METADATA_STATUS_CLOSED) {
+ status = LTTNG_LIVE_ITERATOR_STATUS_END;
+ goto end;
}
if (bt_close_memstream(&metadata_buf, &size, fp)) {
}
goto end;
+
error:
- status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+ if (errno == EINTR) {
+ if (lttng_live_graph_is_canceled(session->lttng_live_msg_iter)) {
+ status = LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
+ }
+ } else {
+ status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+ }
end:
if (fp) {
int closeret;
}
BT_HIDDEN
-ssize_t lttng_live_get_one_metadata_packet(struct lttng_live_trace *trace,
- FILE *fp)
+enum lttng_live_get_one_metadata_status lttng_live_get_one_metadata_packet(
+ struct lttng_live_trace *trace, FILE *fp, size_t *reply_len)
{
uint64_t len = 0;
- int ret;
+ enum lttng_live_get_one_metadata_status metadata_status;
struct lttng_viewer_cmd cmd;
struct lttng_viewer_get_metadata rq;
struct lttng_viewer_metadata_packet rp;
switch (be32toh(rp.status)) {
case LTTNG_VIEWER_METADATA_OK:
- BT_COMP_LOGD("get_metadata : OK");
+ BT_COMP_LOGD("Received get_metadata response : OK");
break;
case LTTNG_VIEWER_NO_NEW_METADATA:
- BT_COMP_LOGD("get_metadata : NO NEW");
- ret = 0;
+ BT_COMP_LOGD("Received get_metadata response: no new");
+ metadata_status = LTTNG_LIVE_GET_ONE_METADATA_STATUS_END;
goto end;
case LTTNG_VIEWER_METADATA_ERR:
- BT_COMP_LOGD("get_metadata : ERR");
- goto error;
+ /*
+ * The Relayd cannot find this stream id. Maybe its
+ * gone already. This can happen in short lived UST app
+ * in a per-pid session.
+ */
+ BT_COMP_LOGD("Received get_metadata response: error");
+ metadata_status = LTTNG_LIVE_GET_ONE_METADATA_STATUS_CLOSED;
+ goto end;
default:
BT_COMP_LOGD("get_metadata : UNKNOWN");
goto error;
}
BT_ASSERT(ret_len == len);
free(data);
- ret = len;
-end:
- return ret;
+ *reply_len = len;
+ metadata_status = LTTNG_LIVE_GET_ONE_METADATA_STATUS_OK;
+
+ goto end;
error_free_data:
free(data);
error:
- return -1;
+ metadata_status = LTTNG_LIVE_GET_ONE_METADATA_STATUS_ERROR;
+
+end:
+ return metadata_status;
}
/*
projects / babeltrace.git / commitdiff
