[lttng-tools.git] / src / bin / lttng-relayd / session.c

/*
 * 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.
 */

#define _LGPL_SOURCE
#include <common/common.h>
#include <common/utils.h>
#include <common/compat/uuid.h>
#include <urcu/rculist.h>

#include "ctf-trace.h"
#include "lttng-relayd.h"
#include "session.h"
#include "sessiond-trace-chunks.h"
#include "stream.h"

/* Global session id used in the session creation. */
static uint64_t last_relay_session_id;
static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;

static int session_set_anonymous_chunk(struct relay_session *session)
{
	int ret = 0;
	struct lttng_trace_chunk *chunk = NULL;
	enum lttng_trace_chunk_status status;
	struct lttng_directory_handle output_directory;
	const char *base_path = opt_output_path;

	if (base_path == NULL) {
		/* No output path defined */
		base_path = utils_get_home_dir();
		if (base_path == NULL) {
			ERR("Home path not found.\n \
					Please specify an output path using -o, --output PATH");
			ret = -1;
			goto end;
		}
	}

	ret = lttng_directory_handle_init(&output_directory, base_path);
	if (ret) {
		goto end;
	}

	chunk = lttng_trace_chunk_create_anonymous();
	if (!chunk) {
		goto end;
	}

	status = lttng_trace_chunk_set_credentials_current_user(chunk);
	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
		ret = -1;
		goto end;
	}

	status = lttng_trace_chunk_set_as_owner(chunk, &output_directory);
	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
		ret = -1;
		goto end;
	}
	session->current_trace_chunk = chunk;
	chunk = NULL;
end:
	lttng_trace_chunk_put(chunk);
	lttng_directory_handle_fini(&output_directory);
	return ret;
}

/*
 * Create a new session by assigning a new session ID.
 *
 * Return allocated session or else NULL.
 */
struct relay_session *session_create(const char *session_name,
		const char *hostname, const char *base_path,
		uint32_t live_timer,
		bool snapshot,
		const lttng_uuid sessiond_uuid,
		const uint64_t *id_sessiond,
		const uint64_t *current_chunk_id,
		const time_t *creation_time,
		uint32_t major,
		uint32_t minor)
{
	int ret;
	struct relay_session *session;

	session = zmalloc(sizeof(*session));
	if (!session) {
		PERROR("Failed to allocate session");
		goto error;
	}
	if (lttng_strncpy(session->session_name, session_name,
			sizeof(session->session_name))) {
	        WARN("Session name exceeds maximal allowed length");
		goto error;
	}
	if (lttng_strncpy(session->hostname, hostname,
			sizeof(session->hostname))) {
		WARN("Hostname exceeds maximal allowed length");
		goto error;
	}
	if (lttng_strncpy(session->base_path, base_path,
			sizeof(session->base_path))) {
		WARN("Base path exceeds maximal allowed length");
		goto error;
	}

	session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
	if (!session->ctf_traces_ht) {
		goto error;
	}

	pthread_mutex_lock(&last_relay_session_id_lock);
	session->id = ++last_relay_session_id;
	pthread_mutex_unlock(&last_relay_session_id_lock);

	session->major = major;
	session->minor = minor;
	lttng_ht_node_init_u64(&session->session_n, session->id);
	urcu_ref_init(&session->ref);
	CDS_INIT_LIST_HEAD(&session->recv_list);
	pthread_mutex_init(&session->lock, NULL);
	pthread_mutex_init(&session->recv_list_lock, NULL);

	session->live_timer = live_timer;
	session->snapshot = snapshot;
	lttng_uuid_copy(session->sessiond_uuid, sessiond_uuid);

	if (id_sessiond) {
		LTTNG_OPTIONAL_SET(&session->id_sessiond, *id_sessiond);
	}

	ret = sessiond_trace_chunk_registry_session_created(
			sessiond_trace_chunk_registry, sessiond_uuid);
	if (ret) {
		goto error;
	}

	if (id_sessiond && current_chunk_id) {
		session->current_trace_chunk =
				sessiond_trace_chunk_registry_get_chunk(
					sessiond_trace_chunk_registry,
					session->sessiond_uuid,
					session->id_sessiond.value,
					*current_chunk_id);
		if (!session->current_trace_chunk) {
		        char uuid_str[UUID_STR_LEN];

			lttng_uuid_to_str(sessiond_uuid, uuid_str);
			ERR("Could not find trace chunk: sessiond = {%s}, sessiond session id = %" PRIu64 ", trace chunk id = %" PRIu64,
					uuid_str, *id_sessiond,
					*current_chunk_id);
                }
	} else if (!id_sessiond) {
		/*
		 * Pre-2.11 peers will not announce trace chunks. An
		 * anonymous trace chunk which will remain set for the
		 * duration of the session is created.
		 */
		ret = session_set_anonymous_chunk(session);
		if (ret) {
			goto error;
		}
	}

	lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
	if (creation_time) {
		LTTNG_OPTIONAL_SET(&session->creation_time, *creation_time);
	}
	return session;

error:
	session_put(session);
	return NULL;
}

/* Should be called with RCU read-side lock held. */
bool session_get(struct relay_session *session)
{
	return urcu_ref_get_unless_zero(&session->ref);
}

/*
 * Lookup a session within the session hash table using the session id
 * as key. A session reference is taken when a session is returned.
 * session_put() must be called on that session.
 *
 * Return session or NULL if not found.
 */
struct relay_session *session_get_by_id(uint64_t id)
{
	struct relay_session *session = NULL;
	struct lttng_ht_node_u64 *node;
	struct lttng_ht_iter iter;

	rcu_read_lock();
	lttng_ht_lookup(sessions_ht, &id, &iter);
	node = lttng_ht_iter_get_node_u64(&iter);
	if (!node) {
		DBG("Session find by ID %" PRIu64 " id NOT found", id);
		goto end;
	}
	session = caa_container_of(node, struct relay_session, session_n);
	DBG("Session find by ID %" PRIu64 " id found", id);
	if (!session_get(session)) {
		session = NULL;
	}
end:
	rcu_read_unlock();
	return session;
}

static void rcu_destroy_session(struct rcu_head *rcu_head)
{
	struct relay_session *session =
			caa_container_of(rcu_head, struct relay_session,
				rcu_node);
	/*
	 * Since each trace has a reference on the session, it means
	 * that if we are at the point where we teardown the session, no
	 * trace belonging to that session exist at this point.
	 * Calling lttng_ht_destroy in call_rcu worker thread so we
	 * don't hold the RCU read-side lock while calling it.
	 */
	lttng_ht_destroy(session->ctf_traces_ht);
	free(session);
}

/*
 * Delete session from the given hash table.
 *
 * Return lttng ht del error code being 0 on success and 1 on failure.
 */
static int session_delete(struct relay_session *session)
{
	struct lttng_ht_iter iter;

	iter.iter.node = &session->session_n.node;
	return lttng_ht_del(sessions_ht, &iter);
}


static void destroy_session(struct relay_session *session)
{
	int ret;

	ret = session_delete(session);
	assert(!ret);
	lttng_trace_chunk_put(session->current_trace_chunk);
	session->current_trace_chunk = NULL;
	lttng_trace_chunk_put(session->pending_closure_trace_chunk);
	session->pending_closure_trace_chunk = NULL;
	ret = sessiond_trace_chunk_registry_session_destroyed(
			sessiond_trace_chunk_registry, session->sessiond_uuid);
	assert(!ret);
	call_rcu(&session->rcu_node, rcu_destroy_session);
}

void session_release(struct urcu_ref *ref)
{
	struct relay_session *session =
			caa_container_of(ref, struct relay_session, ref);

	destroy_session(session);
}

void session_put(struct relay_session *session)
{
	rcu_read_lock();
	urcu_ref_put(&session->ref, session_release);
	rcu_read_unlock();
}

int session_close(struct relay_session *session)
{
	int ret = 0;
	struct ctf_trace *trace;
	struct lttng_ht_iter iter;
	struct relay_stream *stream;

	pthread_mutex_lock(&session->lock);
	DBG("closing session %" PRIu64 ": is conn already closed %d",
			session->id, session->connection_closed);
	session->connection_closed = true;
	pthread_mutex_unlock(&session->lock);

	rcu_read_lock();
	cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
			&iter.iter, trace, node.node) {
		ret = ctf_trace_close(trace);
		if (ret) {
			goto rcu_unlock;
		}
	}
	cds_list_for_each_entry_rcu(stream, &session->recv_list,
			recv_node) {
		/* Close streams which have not been published yet. */
		try_stream_close(stream);
	}
rcu_unlock:
	rcu_read_unlock();
	if (ret) {
		return ret;
	}
	/* Put self-reference from create. */
	session_put(session);
	return ret;
}

int session_abort(struct relay_session *session)
{
	int ret = 0;

	if (!session) {
		return 0;
	}

	pthread_mutex_lock(&session->lock);
	DBG("aborting session %" PRIu64, session->id);
	session->aborted = true;
	pthread_mutex_unlock(&session->lock);
	return ret;
}

void print_sessions(void)
{
	struct lttng_ht_iter iter;
	struct relay_session *session;

	if (!sessions_ht) {
		return;
	}

	rcu_read_lock();
	cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
			session_n.node) {
		if (!session_get(session)) {
			continue;
		}
		DBG("session %p refcount %ld session %" PRIu64,
			session,
			session->ref.refcount,
			session->id);
		session_put(session);
	}
	rcu_read_unlock();
}
Commit	Line	Data
2f8f53af DG	1	/*
	2	* Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
	3	* David Goulet <dgoulet@efficios.com>
7591bab1	4	* 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2f8f53af DG	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License, version 2 only, as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 51
	17	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	18	*/
	19
6c1c0768	20	#define _LGPL_SOURCE
2a174661	21	#include <common/common.h>
a620c891	22	#include <common/utils.h>
1e791a74	23	#include <common/compat/uuid.h>
7591bab1	24	#include <urcu/rculist.h>
2a174661 DG	25
2a174661 DG	26	#include "ctf-trace.h"
a620c891	27	#include "lttng-relayd.h"
2f8f53af	28	#include "session.h"
23c8ff50	29	#include "sessiond-trace-chunks.h"
a620c891	30	#include "stream.h"
2a174661 DG	31
	32	/* Global session id used in the session creation. */
	33	static uint64_t last_relay_session_id;
7591bab1	34	static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
2a174661	35
1e791a74 JG	36	static int session_set_anonymous_chunk(struct relay_session *session)
	37	{
	38	int ret = 0;
	39	struct lttng_trace_chunk *chunk = NULL;
	40	enum lttng_trace_chunk_status status;
	41	struct lttng_directory_handle output_directory;
4f00620d	42	const char *base_path = opt_output_path;
a620c891 JR	43
	44	if (base_path == NULL) {
	45	/* No output path defined */
	46	base_path = utils_get_home_dir();
	47	if (base_path == NULL) {
	48	ERR("Home path not found.\n \
	49	Please specify an output path using -o, --output PATH");
	50	ret = -1;
	51	goto end;
	52	}
	53	}
1e791a74	54
a620c891	55	ret = lttng_directory_handle_init(&output_directory, base_path);
1e791a74 JG	56	if (ret) {
	57	goto end;
	58	}
	59
	60	chunk = lttng_trace_chunk_create_anonymous();
	61	if (!chunk) {
	62	goto end;
	63	}
	64
	65	status = lttng_trace_chunk_set_credentials_current_user(chunk);
	66	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	67	ret = -1;
	68	goto end;
	69	}
	70
	71	status = lttng_trace_chunk_set_as_owner(chunk, &output_directory);
	72	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	73	ret = -1;
	74	goto end;
	75	}
	76	session->current_trace_chunk = chunk;
	77	chunk = NULL;
	78	end:
	79	lttng_trace_chunk_put(chunk);
	80	lttng_directory_handle_fini(&output_directory);
	81	return ret;
	82	}
	83
2a174661 DG	84	/*
	85	* Create a new session by assigning a new session ID.
	86	*
	87	* Return allocated session or else NULL.
	88	*/
7591bab1	89	struct relay_session session_create(const char session_name,
6fa5fe7c	90	const char hostname, const char base_path,
db1da059 JG	91	uint32_t live_timer,
	92	bool snapshot,
	93	const lttng_uuid sessiond_uuid,
	94	const uint64_t *id_sessiond,
	95	const uint64_t *current_chunk_id,
	96	const time_t *creation_time,
	97	uint32_t major,
	98	uint32_t minor)
2a174661	99	{
23c8ff50	100	int ret;
2a174661 DG	101	struct relay_session *session;
	102
	103	session = zmalloc(sizeof(*session));
	104	if (!session) {
1e791a74	105	PERROR("Failed to allocate session");
2a174661 DG	106	goto error;
2a174661 DG	107	}
bb5d54e7 MD	108	if (lttng_strncpy(session->session_name, session_name,
bb5d54e7 MD	109	sizeof(session->session_name))) {
1e791a74	110	WARN("Session name exceeds maximal allowed length");
bb5d54e7 MD	111	goto error;
	112	}
	113	if (lttng_strncpy(session->hostname, hostname,
	114	sizeof(session->hostname))) {
1e791a74	115	WARN("Hostname exceeds maximal allowed length");
bb5d54e7 MD	116	goto error;
bb5d54e7 MD	117	}
6fa5fe7c MD	118	if (lttng_strncpy(session->base_path, base_path,
	119	sizeof(session->base_path))) {
	120	WARN("Base path exceeds maximal allowed length");
	121	goto error;
	122	}
	123
2a174661 DG	124	session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
2a174661 DG	125	if (!session->ctf_traces_ht) {
2a174661 DG	126	goto error;
	127	}
	128
7591bab1	129	pthread_mutex_lock(&last_relay_session_id_lock);
2a174661	130	session->id = ++last_relay_session_id;
7591bab1 MD	131	pthread_mutex_unlock(&last_relay_session_id_lock);
	132
	133	session->major = major;
	134	session->minor = minor;
2a174661	135	lttng_ht_node_init_u64(&session->session_n, session->id);
7591bab1 MD	136	urcu_ref_init(&session->ref);
	137	CDS_INIT_LIST_HEAD(&session->recv_list);
	138	pthread_mutex_init(&session->lock, NULL);
7591bab1 MD	139	pthread_mutex_init(&session->recv_list_lock, NULL);
7591bab1 MD	140
7591bab1 MD	141	session->live_timer = live_timer;
7591bab1 MD	142	session->snapshot = snapshot;
23c8ff50 JG	143	lttng_uuid_copy(session->sessiond_uuid, sessiond_uuid);
23c8ff50 JG	144
1e791a74 JG	145	if (id_sessiond) {
	146	LTTNG_OPTIONAL_SET(&session->id_sessiond, *id_sessiond);
	147	}
	148
23c8ff50 JG	149	ret = sessiond_trace_chunk_registry_session_created(
	150	sessiond_trace_chunk_registry, sessiond_uuid);
	151	if (ret) {
	152	goto error;
	153	}
7591bab1	154
1e791a74 JG	155	if (id_sessiond && current_chunk_id) {
	156	session->current_trace_chunk =
	157	sessiond_trace_chunk_registry_get_chunk(
	158	sessiond_trace_chunk_registry,
	159	session->sessiond_uuid,
	160	session->id_sessiond.value,
	161	*current_chunk_id);
	162	if (!session->current_trace_chunk) {
	163	char uuid_str[UUID_STR_LEN];
	164
	165	lttng_uuid_to_str(sessiond_uuid, uuid_str);
	166	ERR("Could not find trace chunk: sessiond = {%s}, sessiond session id = %" PRIu64 ", trace chunk id = %" PRIu64,
	167	uuid_str, *id_sessiond,
	168	*current_chunk_id);
	169	}
	170	} else if (!id_sessiond) {
	171	/*
	172	* Pre-2.11 peers will not announce trace chunks. An
	173	* anonymous trace chunk which will remain set for the
	174	* duration of the session is created.
	175	*/
	176	ret = session_set_anonymous_chunk(session);
	177	if (ret) {
	178	goto error;
	179	}
	180	}
	181
7591bab1	182	lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
db1da059 JG	183	if (creation_time) {
	184	LTTNG_OPTIONAL_SET(&session->creation_time, *creation_time);
	185	}
bb5d54e7	186	return session;
2a174661 DG	187
2a174661 DG	188	error:
1e791a74	189	session_put(session);
bb5d54e7	190	return NULL;
2a174661	191	}
2f8f53af	192
7591bab1 MD	193	/* Should be called with RCU read-side lock held. */
	194	bool session_get(struct relay_session *session)
	195	{
ce4d4083	196	return urcu_ref_get_unless_zero(&session->ref);
7591bab1 MD	197	}
7591bab1 MD	198
2f8f53af	199	/*
7591bab1 MD	200	* Lookup a session within the session hash table using the session id
	201	* as key. A session reference is taken when a session is returned.
	202	* session_put() must be called on that session.
2f8f53af DG	203	*
	204	* Return session or NULL if not found.
	205	*/
7591bab1	206	struct relay_session *session_get_by_id(uint64_t id)
2f8f53af DG	207	{
2f8f53af DG	208	struct relay_session *session = NULL;
2a174661	209	struct lttng_ht_node_u64 *node;
2f8f53af DG	210	struct lttng_ht_iter iter;
2f8f53af DG	211
7591bab1 MD	212	rcu_read_lock();
7591bab1 MD	213	lttng_ht_lookup(sessions_ht, &id, &iter);
2a174661	214	node = lttng_ht_iter_get_node_u64(&iter);
2f8f53af	215	if (!node) {
2a174661	216	DBG("Session find by ID %" PRIu64 " id NOT found", id);
2f8f53af DG	217	goto end;
	218	}
	219	session = caa_container_of(node, struct relay_session, session_n);
2a174661	220	DBG("Session find by ID %" PRIu64 " id found", id);
7591bab1 MD	221	if (!session_get(session)) {
	222	session = NULL;
	223	}
2f8f53af	224	end:
7591bab1	225	rcu_read_unlock();
2f8f53af DG	226	return session;
2f8f53af DG	227	}
2a174661	228
7591bab1 MD	229	static void rcu_destroy_session(struct rcu_head *rcu_head)
	230	{
	231	struct relay_session *session =
	232	caa_container_of(rcu_head, struct relay_session,
	233	rcu_node);
49e614cb MD	234	/*
	235	* Since each trace has a reference on the session, it means
	236	* that if we are at the point where we teardown the session, no
	237	* trace belonging to that session exist at this point.
	238	* Calling lttng_ht_destroy in call_rcu worker thread so we
	239	* don't hold the RCU read-side lock while calling it.
	240	*/
	241	lttng_ht_destroy(session->ctf_traces_ht);
7591bab1 MD	242	free(session);
	243	}
	244
2a174661 DG	245	/*
	246	* Delete session from the given hash table.
	247	*
	248	* Return lttng ht del error code being 0 on success and 1 on failure.
	249	*/
7591bab1	250	static int session_delete(struct relay_session *session)
2a174661 DG	251	{
	252	struct lttng_ht_iter iter;
	253
2a174661	254	iter.iter.node = &session->session_n.node;
7591bab1	255	return lttng_ht_del(sessions_ht, &iter);
2a174661 DG	256	}
2a174661 DG	257
7591bab1 MD	258
	259	static void destroy_session(struct relay_session *session)
	260	{
	261	int ret;
	262
	263	ret = session_delete(session);
	264	assert(!ret);
639ddf68	265	lttng_trace_chunk_put(session->current_trace_chunk);
c35f9726	266	session->current_trace_chunk = NULL;
62bad3bf JG	267	lttng_trace_chunk_put(session->pending_closure_trace_chunk);
62bad3bf JG	268	session->pending_closure_trace_chunk = NULL;
23c8ff50 JG	269	ret = sessiond_trace_chunk_registry_session_destroyed(
	270	sessiond_trace_chunk_registry, session->sessiond_uuid);
	271	assert(!ret);
7591bab1 MD	272	call_rcu(&session->rcu_node, rcu_destroy_session);
	273	}
	274
	275	void session_release(struct urcu_ref *ref)
2a174661	276	{
7591bab1 MD	277	struct relay_session *session =
7591bab1 MD	278	caa_container_of(ref, struct relay_session, ref);
2a174661	279
7591bab1 MD	280	destroy_session(session);
7591bab1 MD	281	}
2a174661	282
7591bab1 MD	283	void session_put(struct relay_session *session)
	284	{
	285	rcu_read_lock();
7591bab1	286	urcu_ref_put(&session->ref, session_release);
7591bab1	287	rcu_read_unlock();
2a174661 DG	288	}
2a174661 DG	289
7591bab1	290	int session_close(struct relay_session *session)
2a174661 DG	291	{
2a174661 DG	292	int ret = 0;
7591bab1 MD	293	struct ctf_trace *trace;
	294	struct lttng_ht_iter iter;
	295	struct relay_stream *stream;
	296
	297	pthread_mutex_lock(&session->lock);
	298	DBG("closing session %" PRIu64 ": is conn already closed %d",
	299	session->id, session->connection_closed);
7591bab1	300	session->connection_closed = true;
7591bab1	301	pthread_mutex_unlock(&session->lock);
2a174661	302
7591bab1 MD	303	rcu_read_lock();
	304	cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
	305	&iter.iter, trace, node.node) {
	306	ret = ctf_trace_close(trace);
	307	if (ret) {
	308	goto rcu_unlock;
2a174661 DG	309	}
2a174661 DG	310	}
7591bab1 MD	311	cds_list_for_each_entry_rcu(stream, &session->recv_list,
7591bab1 MD	312	recv_node) {
bda7c7b9 JG	313	/* Close streams which have not been published yet. */
bda7c7b9 JG	314	try_stream_close(stream);
7591bab1 MD	315	}
	316	rcu_unlock:
	317	rcu_read_unlock();
	318	if (ret) {
	319	return ret;
	320	}
	321	/* Put self-reference from create. */
	322	session_put(session);
	323	return ret;
2a174661 DG	324	}
2a174661 DG	325
98ba050e JR	326	int session_abort(struct relay_session *session)
	327	{
	328	int ret = 0;
	329
	330	if (!session) {
	331	return 0;
	332	}
	333
	334	pthread_mutex_lock(&session->lock);
	335	DBG("aborting session %" PRIu64, session->id);
98ba050e	336	session->aborted = true;
98ba050e JR	337	pthread_mutex_unlock(&session->lock);
	338	return ret;
	339	}
	340
7591bab1	341	void print_sessions(void)
2a174661	342	{
2a174661	343	struct lttng_ht_iter iter;
7591bab1	344	struct relay_session *session;
2a174661	345
ce3f3ba3 JG	346	if (!sessions_ht) {
	347	return;
	348	}
	349
2a174661	350	rcu_read_lock();
7591bab1 MD	351	cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
	352	session_n.node) {
	353	if (!session_get(session)) {
	354	continue;
	355	}
	356	DBG("session %p refcount %ld session %" PRIu64,
	357	session,
	358	session->ref.refcount,
	359	session->id);
	360	session_put(session);
2a174661	361	}
2a174661	362	rcu_read_unlock();
2a174661	363	}