relay: use urcu_ref_get_unless_zero

[lttng-tools.git] / src / bin / lttng-relayd / ctf-trace.h

#ifndef _CTF_TRACE_H
#define _CTF_TRACE_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
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <inttypes.h>
#include <urcu/ref.h>

#include <common/hashtable/hashtable.h>

#include "session.h"
#include "stream.h"
#include "viewer-stream.h"

struct ctf_trace {
	struct urcu_ref ref;		/* Every stream has a ref on the trace. */
	struct relay_session *session;	/* Back ref to trace session */

	/*
	 * The ctf_trace lock nests inside the session lock.
	 */
	pthread_mutex_t lock;
	uint64_t id;
	struct relay_viewer_stream *viewer_metadata_stream;	/* RCU protected */

	/*
	 * Relay streams associated with this ctf trace.
	 * Updates are protected by the stream_list lock.
	 * Traversals are protected by RCU.
	 */
	struct cds_list_head stream_list;
	pthread_mutex_t stream_list_lock;

	/*
	 * Node within session trace hash table. Node is indexed by
	 * stream path name.
	 */
	struct lttng_ht_node_str node;
	struct rcu_head rcu_node;	/* For call_rcu teardown. */
};

struct ctf_trace *ctf_trace_get_by_path_or_create(struct relay_session *session,
		char *path_name);
bool ctf_trace_get(struct ctf_trace *trace);
void ctf_trace_put(struct ctf_trace *trace);

int ctf_trace_close(struct ctf_trace *trace);

struct relay_viewer_stream *ctf_trace_get_viewer_metadata_stream(struct ctf_trace *trace);

#endif /* _CTF_TRACE_H */