uint64_t session_id, unsigned int ignore_sent_flag)
{
ssize_t ret;
- struct lttng_viewer_stream send_stream;
struct lttng_ht_iter iter;
struct relay_viewer_stream *vstream;
cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
stream_n.node) {
struct ctf_trace *ctf_trace;
+ struct lttng_viewer_stream send_stream = {};
health_code_update();
*
* Return 0 on success or else a negative value.
*/
-static int make_viewer_streams(struct relay_session *session,
- struct lttng_trace_chunk *viewer_trace_chunk,
+static int make_viewer_streams(struct relay_session *relay_session,
+ struct relay_viewer_session *viewer_session,
enum lttng_viewer_seek seek_t,
uint32_t *nb_total,
uint32_t *nb_unsent,
int ret;
struct lttng_ht_iter iter;
struct ctf_trace *ctf_trace;
+ struct relay_stream *relay_stream = NULL;
- assert(session);
- ASSERT_LOCKED(session->lock);
+ assert(relay_session);
+ ASSERT_LOCKED(relay_session->lock);
- if (!viewer_trace_chunk) {
- ERR("Internal error: viewer session associated with session \"%s\" has a NULL trace chunk",
- session->session_name);
- ret = -1;
- goto error;
- }
-
- if (session->connection_closed) {
+ if (relay_session->connection_closed) {
*closed = true;
}
* used for a the given session id only.
*/
rcu_read_lock();
- cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
- node.node) {
+ cds_lfht_for_each_entry (relay_session->ctf_traces_ht->ht, &iter.iter,
+ ctf_trace, node.node) {
bool trace_has_metadata_stream = false;
- struct relay_stream *stream;
health_code_update();
* Iterate over all the streams of the trace to see if we have a
* metadata stream.
*/
- cds_list_for_each_entry_rcu(
- stream, &ctf_trace->stream_list, stream_node)
+ cds_list_for_each_entry_rcu(relay_stream,
+ &ctf_trace->stream_list, stream_node)
{
- if (stream->is_metadata) {
+ bool is_metadata_stream;
+
+ pthread_mutex_lock(&relay_stream->lock);
+ is_metadata_stream = relay_stream->is_metadata;
+ pthread_mutex_unlock(&relay_stream->lock);
+
+ if (is_metadata_stream) {
trace_has_metadata_stream = true;
break;
}
}
+ relay_stream = NULL;
+
/*
* If there is no metadata stream in this trace at the moment
* and we never sent one to the viewer, skip the trace. We
continue;
}
- cds_list_for_each_entry_rcu(stream, &ctf_trace->stream_list, stream_node) {
- struct relay_viewer_stream *vstream;
+ cds_list_for_each_entry_rcu(relay_stream,
+ &ctf_trace->stream_list, stream_node)
+ {
+ struct relay_viewer_stream *viewer_stream;
- if (!stream_get(stream)) {
+ if (!stream_get(relay_stream)) {
continue;
}
+
+ pthread_mutex_lock(&relay_stream->lock);
/*
* stream published is protected by the session lock.
*/
- if (!stream->published) {
+ if (!relay_stream->published) {
goto next;
}
- vstream = viewer_stream_get_by_id(stream->stream_handle);
- if (!vstream) {
+ viewer_stream = viewer_stream_get_by_id(
+ relay_stream->stream_handle);
+ if (!viewer_stream) {
+ struct lttng_trace_chunk *viewer_stream_trace_chunk = NULL;
+
/*
* Save that we sent the metadata stream to the
* viewer. So that we know what trace the viewer
* is aware of.
*/
- if (stream->is_metadata) {
- ctf_trace->metadata_stream_sent_to_viewer =
- true;
+ if (relay_stream->is_metadata) {
+ ctf_trace->metadata_stream_sent_to_viewer = true;
+ }
+
+ /*
+ * If a rotation is ongoing, use a copy of the
+ * relay stream's chunk to ensure the stream
+ * files exist.
+ *
+ * Otherwise, the viewer session's current trace
+ * chunk can be used safely.
+ */
+ if ((relay_stream->ongoing_rotation.is_set ||
+ session_has_ongoing_rotation(relay_session)) &&
+ relay_stream->trace_chunk) {
+ viewer_stream_trace_chunk = lttng_trace_chunk_copy(
+ relay_stream->trace_chunk);
+ if (!viewer_stream_trace_chunk) {
+ ret = -1;
+ ctf_trace_put(ctf_trace);
+ goto error_unlock;
+ }
+ } else {
+ /*
+ * Transition the viewer session into the newest trace chunk available.
+ */
+ if (!lttng_trace_chunk_ids_equal(viewer_session->current_trace_chunk,
+ relay_stream->trace_chunk)) {
+
+ ret = viewer_session_set_trace_chunk_copy(
+ viewer_session,
+ relay_stream->trace_chunk);
+ if (ret) {
+ ret = -1;
+ ctf_trace_put(ctf_trace);
+ goto error_unlock;
+ }
+ }
+
+ if (relay_stream->trace_chunk) {
+ /*
+ * If the corresponding relay
+ * stream's trace chunk is set,
+ * the viewer stream will be
+ * created under it.
+ *
+ * Note that a relay stream can
+ * have a NULL output trace
+ * chunk (for instance, after a
+ * clear against a stopped
+ * session).
+ */
+ const bool reference_acquired = lttng_trace_chunk_get(
+ viewer_session->current_trace_chunk);
+
+ assert(reference_acquired);
+ viewer_stream_trace_chunk =
+ viewer_session->current_trace_chunk;
+ }
}
- vstream = viewer_stream_create(stream,
- viewer_trace_chunk, seek_t);
- if (!vstream) {
+
+ viewer_stream = viewer_stream_create(
+ relay_stream,
+ viewer_stream_trace_chunk,
+ seek_t);
+ lttng_trace_chunk_put(viewer_stream_trace_chunk);
+ viewer_stream_trace_chunk = NULL;
+ if (!viewer_stream) {
ret = -1;
ctf_trace_put(ctf_trace);
- stream_put(stream);
goto error_unlock;
}
* Ensure a self-reference is preserved even
* after we have put our local reference.
*/
- if (!viewer_stream_get(vstream)) {
+ if (!viewer_stream_get(viewer_stream)) {
ERR("Unable to get self-reference on viewer stream, logic error.");
abort();
}
} else {
- if (!vstream->sent_flag && nb_unsent) {
+ if (!viewer_stream->sent_flag && nb_unsent) {
/* Update number of unsent stream counter. */
(*nb_unsent)++;
}
}
/* Update number of total stream counter. */
if (nb_total) {
- if (stream->is_metadata) {
- if (!stream->closed ||
- stream->metadata_received > vstream->metadata_sent) {
+ if (relay_stream->is_metadata) {
+ if (!relay_stream->closed ||
+ relay_stream->metadata_received >
+ viewer_stream->metadata_sent) {
(*nb_total)++;
}
} else {
- if (!stream->closed ||
- !(((int64_t) (stream->prev_data_seq - stream->last_net_seq_num)) >= 0)) {
-
+ if (!relay_stream->closed ||
+ !(((int64_t)(relay_stream->prev_data_seq -
+ relay_stream->last_net_seq_num)) >=
+ 0)) {
(*nb_total)++;
}
}
}
/* Put local reference. */
- viewer_stream_put(vstream);
+ viewer_stream_put(viewer_stream);
next:
- stream_put(stream);
+ pthread_mutex_unlock(&relay_stream->lock);
+ stream_put(relay_stream);
}
+ relay_stream = NULL;
ctf_trace_put(ctf_trace);
}
error_unlock:
rcu_read_unlock();
-error:
+
+ if (relay_stream) {
+ pthread_mutex_unlock(&relay_stream->lock);
+ stream_put(relay_stream);
+ }
+
return ret;
}
/* Skip closed session */
goto next_session;
}
- if (!session->current_trace_chunk) {
- /*
- * Skip un-attachable session. It is either
- * being destroyed or has not had a trace
- * chunk created against it yet.
- */
- goto next_session;
- }
if (count >= buf_count) {
struct lttng_viewer_session *newbuf;
goto send_reply;
}
+ /*
+ * For any new stream, create it with LTTNG_VIEWER_SEEK_BEGINNING since
+ * that at this point the client is already attached to the session.Aany
+ * initial stream will have been created with the seek type at attach
+ * time (for now most readers use the LTTNG_VIEWER_SEEK_LAST on attach).
+ * Otherwise any event happening in a new stream between the attach and
+ * a call to viewer_get_new_streams will be "lost" (never received) from
+ * the viewer's point of view.
+ */
pthread_mutex_lock(&session->lock);
+ /*
+ * If a session rotation is ongoing, do not attempt to open any
+ * stream, because the chunk can be in an intermediate state
+ * due to directory renaming.
+ */
+ if (session_has_ongoing_rotation(session)) {
+ DBG("Relay session %" PRIu64 " rotation ongoing", session_id);
+ response.status = htobe32(LTTNG_VIEWER_NEW_STREAMS_NO_NEW);
+ goto send_reply_unlock;
+ }
ret = make_viewer_streams(session,
- conn->viewer_session->current_trace_chunk,
- LTTNG_VIEWER_SEEK_LAST, &nb_total, &nb_unsent,
+ conn->viewer_session,
+ LTTNG_VIEWER_SEEK_BEGINNING, &nb_total, &nb_unsent,
&nb_created, &closed);
if (ret < 0) {
goto error_unlock_session;
DBG("Attach session ID %" PRIu64 " received", session_id);
pthread_mutex_lock(&session->lock);
- if (!session->current_trace_chunk) {
- /*
- * Session is either being destroyed or it never had a trace
- * chunk created against it.
- */
- DBG("Session requested by live client has no current trace chunk, returning unknown session");
- response.status = htobe32(LTTNG_VIEWER_ATTACH_UNK);
- goto send_reply;
- }
if (session->live_timer == 0) {
DBG("Not live session");
response.status = htobe32(LTTNG_VIEWER_ATTACH_NOT_LIVE);
goto send_reply;
}
+ /*
+ * If a session rotation is ongoing, do not attempt to open any
+ * stream, because the chunk can be in an intermediate state
+ * due to directory renaming.
+ */
+ if (session_has_ongoing_rotation(session)) {
+ DBG("Relay session %" PRIu64 " rotation ongoing", session_id);
+ send_streams = 0;
+ goto send_reply;
+ }
+
ret = make_viewer_streams(session,
- conn->viewer_session->current_trace_chunk, seek_type,
+ conn->viewer_session, seek_type,
&nb_streams, NULL, NULL, &closed);
if (ret < 0) {
goto end_put_session;
/*
* First time, we open the index file and at least one index is ready.
*/
- if (rstream->index_received_seqcount == 0) {
+ if (rstream->index_received_seqcount == 0 ||
+ !vstream->stream_file.trace_chunk) {
ret = -ENOENT;
goto end;
}
+
chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
vstream->stream_file.trace_chunk, rstream->path_name,
rstream->channel_name, rstream->tracefile_size,
return 1;
}
+static
+void viewer_stream_rotate_to_trace_chunk(struct relay_viewer_stream *vstream,
+ struct lttng_trace_chunk *new_trace_chunk)
+{
+ lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
+
+ if (new_trace_chunk) {
+ const bool acquired_reference = lttng_trace_chunk_get(
+ new_trace_chunk);
+
+ assert(acquired_reference);
+ }
+
+ vstream->stream_file.trace_chunk = new_trace_chunk;
+ viewer_stream_sync_tracefile_array_tail(vstream);
+ viewer_stream_close_files(vstream);
+}
+
/*
* Send the next index for a stream.
*
metadata_viewer_stream =
ctf_trace_get_viewer_metadata_stream(ctf_trace);
+ /*
+ * Hold the session lock to protect against concurrent changes
+ * to the chunk files (e.g. rename done by clear), which are
+ * protected by the session ongoing rotation state. Those are
+ * synchronized with the session lock.
+ */
+ pthread_mutex_lock(&rstream->trace->session->lock);
pthread_mutex_lock(&rstream->lock);
/*
goto send_reply;
}
- if (rstream->trace->session->ongoing_rotation) {
+ if (session_has_ongoing_rotation(rstream->trace->session)) {
/* Rotation is ongoing, try again later. */
viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_RETRY);
goto send_reply;
}
- if (rstream->trace_chunk) {
- uint64_t rchunk_id, vchunk_id;
+ /*
+ * Transition the viewer session into the newest trace chunk available.
+ */
+ if (!lttng_trace_chunk_ids_equal(
+ conn->viewer_session->current_trace_chunk,
+ rstream->trace_chunk)) {
+ DBG("Relay stream and viewer chunk ids differ");
- /*
- * If the relay stream is not yet closed, ensure the viewer
- * chunk matches the relay chunk after clear.
- */
- if (lttng_trace_chunk_get_id(rstream->trace_chunk,
- &rchunk_id) != LTTNG_TRACE_CHUNK_STATUS_OK) {
- viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
- goto send_reply;
- }
- if (lttng_trace_chunk_get_id(
- conn->viewer_session->current_trace_chunk,
- &vchunk_id) != LTTNG_TRACE_CHUNK_STATUS_OK) {
+ ret = viewer_session_set_trace_chunk_copy(
+ conn->viewer_session,
+ rstream->trace_chunk);
+ if (ret) {
viewer_index.status = htobe32(LTTNG_VIEWER_INDEX_ERR);
goto send_reply;
}
-
- if (rchunk_id != vchunk_id) {
- DBG("Relay and viewer chunk ids differ: "
- "rchunk_id %" PRIu64 " vchunk_id %" PRIu64,
- rchunk_id, vchunk_id);
-
- lttng_trace_chunk_put(
- conn->viewer_session->current_trace_chunk);
- conn->viewer_session->current_trace_chunk = NULL;
- ret = viewer_session_set_trace_chunk_copy(
- conn->viewer_session,
- rstream->trace_chunk);
- if (ret) {
- viewer_index.status =
- htobe32(LTTNG_VIEWER_INDEX_ERR);
- goto send_reply;
- }
- }
}
- if (conn->viewer_session->current_trace_chunk !=
- vstream->stream_file.trace_chunk) {
- bool acquired_reference;
- DBG("Viewer session and viewer stream chunk differ: "
+ /*
+ * Transition the viewer stream into the latest trace chunk available.
+ *
+ * Note that the stream must _not_ rotate in one precise condition:
+ * the relay stream has rotated to a NULL trace chunk and the viewer
+ * stream is consuming the trace chunk that was active just before
+ * that rotation to NULL.
+ *
+ * This allows clients to consume all the packets of a trace chunk
+ * after a session's destruction.
+ */
+ if (!lttng_trace_chunk_ids_equal(conn->viewer_session->current_trace_chunk, vstream->stream_file.trace_chunk) &&
+ !(rstream->completed_rotation_count == vstream->last_seen_rotation_count + 1 && !rstream->trace_chunk)) {
+ DBG("Viewer session and viewer stream chunk IDs differ: "
"vsession chunk %p vstream chunk %p",
conn->viewer_session->current_trace_chunk,
vstream->stream_file.trace_chunk);
- lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
- acquired_reference = lttng_trace_chunk_get(conn->viewer_session->current_trace_chunk);
- assert(acquired_reference);
- vstream->stream_file.trace_chunk =
- conn->viewer_session->current_trace_chunk;
- viewer_stream_sync_tracefile_array_tail(vstream);
- viewer_stream_close_files(vstream);
+ viewer_stream_rotate_to_trace_chunk(vstream,
+ conn->viewer_session->current_trace_chunk);
+ vstream->last_seen_rotation_count =
+ rstream->completed_rotation_count;
}
ret = check_index_status(vstream, rstream, ctf_trace, &viewer_index);
send_reply:
if (rstream) {
pthread_mutex_unlock(&rstream->lock);
+ pthread_mutex_unlock(&rstream->trace->session->lock);
}
if (metadata_viewer_stream) {
error_put:
pthread_mutex_unlock(&rstream->lock);
+ pthread_mutex_unlock(&rstream->trace->session->lock);
if (metadata_viewer_stream) {
viewer_stream_put(metadata_viewer_stream);
}
goto send_reply;
error:
+ /* No payload to send on error. */
+ reply_size = sizeof(reply_header);
reply_header.status = htobe32(LTTNG_VIEWER_GET_PACKET_ERR);
send_reply:
* an error.
*/
if (vstream->metadata_sent > 0) {
- vstream->stream->no_new_metadata_notified = true;
- if (vstream->stream->closed) {
+ if (vstream->stream->closed && vstream->stream->no_new_metadata_notified) {
/* Release ownership for the viewer metadata stream. */
viewer_stream_put(vstream);
}
+ vstream->stream->no_new_metadata_notified = true;
}
goto send_reply;
}
+ if (vstream->stream->trace_chunk &&
+ !lttng_trace_chunk_ids_equal(
+ conn->viewer_session->current_trace_chunk,
+ vstream->stream->trace_chunk)) {
+ /* A rotation has occurred on the relay stream. */
+ DBG("Metadata relay stream and viewer chunk ids differ");
+
+ ret = viewer_session_set_trace_chunk_copy(
+ conn->viewer_session,
+ vstream->stream->trace_chunk);
+ if (ret) {
+ reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
+ goto send_reply;
+ }
+ }
+
+ if (conn->viewer_session->current_trace_chunk &&
+ !lttng_trace_chunk_ids_equal(conn->viewer_session->current_trace_chunk,
+ vstream->stream_file.trace_chunk)) {
+ bool acquired_reference;
+
+ DBG("Viewer session and viewer stream chunk differ: "
+ "vsession chunk %p vstream chunk %p",
+ conn->viewer_session->current_trace_chunk,
+ vstream->stream_file.trace_chunk);
+ lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
+ acquired_reference = lttng_trace_chunk_get(conn->viewer_session->current_trace_chunk);
+ assert(acquired_reference);
+ vstream->stream_file.trace_chunk =
+ conn->viewer_session->current_trace_chunk;
+ viewer_stream_close_files(vstream);
+ }
+
len = vstream->stream->metadata_received - vstream->metadata_sent;
- /* first time, we open the metadata file */
- if (!vstream->stream_file.handle) {
+ if (!vstream->stream_file.trace_chunk) {
+ reply.status = htobe32(LTTNG_VIEWER_NO_NEW_METADATA);
+ len = 0;
+ goto send_reply;
+ } else if (vstream->stream_file.trace_chunk &&
+ !vstream->stream_file.handle && len > 0) {
+ /*
+ * Either this is the first time the metadata file is read, or a
+ * rotation of the corresponding relay stream has occurred.
+ */
struct fs_handle *fs_handle;
char file_path[LTTNG_PATH_MAX];
enum lttng_trace_chunk_status status;
goto error;
}
vstream->stream_file.handle = fs_handle;
+
+ if (vstream->metadata_sent != 0) {
+ /*
+ * The client does not expect to receive any metadata
+ * it has received and metadata files in successive
+ * chunks must be a strict superset of one another.
+ *
+ * Skip the first `metadata_sent` bytes to ensure
+ * they are not sent a second time to the client.
+ *
+ * Baring a block layer error or an internal error,
+ * this seek should not fail as
+ * `vstream->stream->metadata_received` is reset when
+ * a relay stream is rotated. If this is reached, it is
+ * safe to assume that
+ * `metadata_received` > `metadata_sent`.
+ */
+ const off_t seek_ret = fs_handle_seek(fs_handle,
+ vstream->metadata_sent, SEEK_SET);
+
+ if (seek_ret < 0) {
+ PERROR("Failed to seek metadata viewer stream file to `sent` position: pos = %" PRId64,
+ vstream->metadata_sent);
+ reply.status = htobe32(LTTNG_VIEWER_METADATA_ERR);
+ goto send_reply;
+ }
+ }
}
reply.len = htobe64(len);
fs_handle_put_fd(vstream->stream_file.handle);
fd = -1;
if (read_len < len) {
- PERROR("Relay reading metadata file");
- goto error;
+ if (read_len < 0) {
+ PERROR("Failed to read metadata file");
+ goto error;
+ } else {
+ /*
+ * A clear has been performed which prevents the relay
+ * from sending `len` bytes of metadata.
+ *
+ * It is important not to send any metadata if we
+ * couldn't read all the available metadata in one shot:
+ * sending partial metadata can cause the client to
+ * attempt to parse an incomplete (incoherent) metadata
+ * stream, which would result in an error.
+ */
+ const off_t seek_ret = fs_handle_seek(
+ vstream->stream_file.handle, -read_len,
+ SEEK_CUR);
+
+ DBG("Failed to read metadata: requested = %" PRIu64 ", got = %zd",
+ len, read_len);
+ read_len = 0;
+ len = 0;
+ if (seek_ret < 0) {
+ PERROR("Failed to restore metadata file position after partial read");
+ ret = -1;
+ goto error;
+ }
+ }
}
vstream->metadata_sent += read_len;
reply.status = htobe32(LTTNG_VIEWER_METADATA_OK);