Fix: Relay daemon ownership and reference counting

[lttng-tools.git] / src / bin / lttng-relayd / viewer-stream.h

diff --git a/src/bin/lttng-relayd/viewer-stream.h b/src/bin/lttng-relayd/viewer-stream.h
index 003b1197cfd2807aed54c73fd6e25393d0f58a31..cc46db4e2a3545cb283ddb5c3260001bcf82d320 100644 (file)
--- a/src/bin/lttng-relayd/viewer-stream.h
+++ b/src/bin/lttng-relayd/viewer-stream.h
@@ -1,6 +1,10 @@
+#ifndef _VIEWER_STREAM_H
+#define _VIEWER_STREAM_H
+
 /*
  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
  *                      David Goulet <dgoulet@efficios.com>
+ *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License, version 2 only, as
@@ -16,9 +20,6 @@
  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef _VIEWER_STREAM_H
-#define _VIEWER_STREAM_H
-
 #include <limits.h>
 #include <inttypes.h>
 #include <pthread.h>
@@ -29,61 +30,58 @@
 #include "lttng-viewer-abi.h"
 #include "stream.h"
 
-/* Stub */
 struct relay_stream;
 
 /*
- * Shadow copy of the relay_stream structure for the viewer side.  The only
- * fields updated by the writer (streaming side) after allocation are :
- * total_index_received and close_flag. Everything else is updated by the
- * reader (viewer side).
+ * The viewer stream's lifetime is the intersection of their viewer connection's
+ * lifetime and the duration during which at least:
+ * a) their input source is still active
+ * b) they still have data left to send to the client.
+ *
+ * This means that both the sessiond/consumerd connection or the viewer
+ * connection may tear down (and unpublish) a relay_viewer_stream.
+ *
+ * Viewer stream updates are protected by their associated stream's lock.
  */
 struct relay_viewer_stream {
-       uint64_t stream_handle;
-       uint64_t session_id;
-       int read_fd;
-       int index_read_fd;
+       struct urcu_ref ref;
+       pthread_mutex_t reflock;
+
+       /* Back ref to stream. */
+       struct relay_stream *stream;
+
+       /* FD from which to read the stream data. */
+       struct stream_fd *stream_fd;
+       /* FD from which to read the index data. */
+       struct stream_fd *index_fd;
+
        char *path_name;
        char *channel_name;
+
+       uint64_t current_tracefile_id;
+       /* Free-running counter. */
+       uint64_t current_tracefile_seq;
+
        uint64_t last_sent_index;
-       uint64_t total_index_received;
-       uint64_t tracefile_count;
-       uint64_t tracefile_count_current;
-       /* Stop after reading this tracefile. */
-       uint64_t tracefile_count_last;
+
+       /* Indicates if this stream has been sent to a viewer client. */
+       bool sent_flag;
+       /* For metadata stream, how much metadata has been sent. */
+       uint64_t metadata_sent;
+
        struct lttng_ht_node_u64 stream_n;
        struct rcu_head rcu_node;
-       struct ctf_trace *ctf_trace;
-       /*
-        * This lock blocks only when the writer is about to start overwriting
-        * a file currently read by the reader.
-        *
-        * This is nested INSIDE the viewer_stream_rotation_lock.
-        */
-       pthread_mutex_t overwrite_lock;
-       /* Information telling us if the stream is a metadata stream. */
-       unsigned int metadata_flag:1;
-       /*
-        * Information telling us that the stream is closed in write, so
-        * we don't expect new indexes and we can read up to EOF.
-        */
-       unsigned int close_write_flag:1;
-       /*
-        * If the streaming side closes a FD in use in the viewer side,
-        * it sets this flag to inform that it is a normal error.
-        */
-       unsigned int abort_flag:1;
-       /* Indicates if this stream has been sent to a viewer client. */
-       unsigned int sent_flag:1;
 };
 
 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
-               enum lttng_viewer_seek seek_t, struct ctf_trace *ctf_trace);
-struct relay_viewer_stream *viewer_stream_find_by_id(uint64_t id);
-void viewer_stream_destroy(struct ctf_trace *ctf_trace,
-               struct relay_viewer_stream *stream);
-void viewer_stream_delete(struct relay_viewer_stream *stream);
-int viewer_stream_rotate(struct relay_viewer_stream *vstream,
-               struct relay_stream *stream);
+               enum lttng_viewer_seek seek_t);
+
+struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id);
+bool viewer_stream_get(struct relay_viewer_stream *vstream);
+void viewer_stream_put(struct relay_viewer_stream *vstream);
+int viewer_stream_rotate(struct relay_viewer_stream *vstream);
+bool viewer_stream_is_tracefile_seq_readable(struct relay_viewer_stream *vstream,
+               uint64_t seq);
+void print_viewer_streams(void);
 
 #endif /* _VIEWER_STREAM_H */