[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 _GNU_SOURCE
#define _LGPL_SOURCE
#include <common/common.h>
#include <urcu/rculist.h>

#include "lttng-relayd.h"
#include "ctf-trace.h"
#include "session.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;

/*
 * 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, uint32_t live_timer,
		bool snapshot, uint32_t major, uint32_t minor)
{
	struct relay_session *session;

	session = zmalloc(sizeof(*session));
	if (!session) {
		PERROR("relay session zmalloc");
		goto error;
	}
	if (lttng_strncpy(session->session_name, session_name,
			sizeof(session->session_name))) {
		goto error;
	}
	if (lttng_strncpy(session->hostname, hostname,
			sizeof(session->hostname))) {
		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->reflock, NULL);
	pthread_mutex_init(&session->recv_list_lock, NULL);

	session->live_timer = live_timer;
	session->snapshot = snapshot;

	lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
	return session;

error:
	free(session);
	return NULL;
}

/* Should be called with RCU read-side lock held. */
bool session_get(struct relay_session *session)
{
	bool has_ref = false;

	pthread_mutex_lock(&session->reflock);
	if (session->ref.refcount != 0) {
		has_ref = true;
		urcu_ref_get(&session->ref);
	}
	pthread_mutex_unlock(&session->reflock);

	return has_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);
	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();
	pthread_mutex_lock(&session->reflock);
	urcu_ref_put(&session->ref, session_release);
	pthread_mutex_unlock(&session->reflock);
	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);
	if (session->connection_closed) {
		ret = -1;
		goto unlock;
	}
	session->connection_closed = true;
unlock:
	pthread_mutex_unlock(&session->lock);
	if (ret) {
		return ret;
	}

	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;
}

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>
5a693d30	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
2a174661	20	#define _GNU_SOURCE
6c1c0768	21	#define _LGPL_SOURCE
2a174661	22	#include <common/common.h>
5a693d30	23	#include <urcu/rculist.h>
2a174661	24
5a693d30	25	#include "lttng-relayd.h"
2a174661	26	#include "ctf-trace.h"
2f8f53af	27	#include "session.h"
2a174661 DG	28	#include "stream.h"
	29
	30	/* Global session id used in the session creation. */
	31	static uint64_t last_relay_session_id;
5a693d30	32	static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
2a174661 DG	33
	34	/*
	35	* Create a new session by assigning a new session ID.
	36	*
	37	* Return allocated session or else NULL.
	38	*/
5a693d30 MD	39	struct relay_session session_create(const char session_name,
	40	const char *hostname, uint32_t live_timer,
	41	bool snapshot, uint32_t major, uint32_t minor)
2a174661 DG	42	{
	43	struct relay_session *session;
	44
	45	session = zmalloc(sizeof(*session));
	46	if (!session) {
	47	PERROR("relay session zmalloc");
	48	goto error;
	49	}
2e8d52df MD	50	if (lttng_strncpy(session->session_name, session_name,
	51	sizeof(session->session_name))) {
	52	goto error;
	53	}
	54	if (lttng_strncpy(session->hostname, hostname,
	55	sizeof(session->hostname))) {
	56	goto error;
	57	}
2a174661 DG	58	session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
2a174661 DG	59	if (!session->ctf_traces_ht) {
2a174661 DG	60	goto error;
	61	}
	62
5a693d30	63	pthread_mutex_lock(&last_relay_session_id_lock);
2a174661	64	session->id = ++last_relay_session_id;
5a693d30 MD	65	pthread_mutex_unlock(&last_relay_session_id_lock);
	66
	67	session->major = major;
	68	session->minor = minor;
2a174661	69	lttng_ht_node_init_u64(&session->session_n, session->id);
5a693d30 MD	70	urcu_ref_init(&session->ref);
	71	CDS_INIT_LIST_HEAD(&session->recv_list);
	72	pthread_mutex_init(&session->lock, NULL);
	73	pthread_mutex_init(&session->reflock, NULL);
	74	pthread_mutex_init(&session->recv_list_lock, NULL);
	75
5a693d30 MD	76	session->live_timer = live_timer;
	77	session->snapshot = snapshot;
	78
	79	lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
2e8d52df	80	return session;
2a174661 DG	81
2a174661 DG	82	error:
2e8d52df MD	83	free(session);
2e8d52df MD	84	return NULL;
2a174661	85	}
2f8f53af	86
5a693d30 MD	87	/* Should be called with RCU read-side lock held. */
	88	bool session_get(struct relay_session *session)
	89	{
	90	bool has_ref = false;
	91
	92	pthread_mutex_lock(&session->reflock);
	93	if (session->ref.refcount != 0) {
	94	has_ref = true;
	95	urcu_ref_get(&session->ref);
	96	}
	97	pthread_mutex_unlock(&session->reflock);
	98
	99	return has_ref;
	100	}
	101
2f8f53af	102	/*
5a693d30 MD	103	* Lookup a session within the session hash table using the session id
	104	* as key. A session reference is taken when a session is returned.
	105	* session_put() must be called on that session.
2f8f53af DG	106	*
	107	* Return session or NULL if not found.
	108	*/
5a693d30	109	struct relay_session *session_get_by_id(uint64_t id)
2f8f53af DG	110	{
2f8f53af DG	111	struct relay_session *session = NULL;
2a174661	112	struct lttng_ht_node_u64 *node;
2f8f53af DG	113	struct lttng_ht_iter iter;
2f8f53af DG	114
5a693d30 MD	115	rcu_read_lock();
5a693d30 MD	116	lttng_ht_lookup(sessions_ht, &id, &iter);
2a174661	117	node = lttng_ht_iter_get_node_u64(&iter);
2f8f53af	118	if (!node) {
2a174661	119	DBG("Session find by ID %" PRIu64 " id NOT found", id);
2f8f53af DG	120	goto end;
	121	}
	122	session = caa_container_of(node, struct relay_session, session_n);
2a174661	123	DBG("Session find by ID %" PRIu64 " id found", id);
5a693d30 MD	124	if (!session_get(session)) {
	125	session = NULL;
	126	}
2f8f53af	127	end:
5a693d30	128	rcu_read_unlock();
2f8f53af DG	129	return session;
2f8f53af DG	130	}
2a174661	131
5a693d30 MD	132	static void rcu_destroy_session(struct rcu_head *rcu_head)
	133	{
	134	struct relay_session *session =
	135	caa_container_of(rcu_head, struct relay_session,
	136	rcu_node);
c65ce455 MD	137	/*
	138	* Since each trace has a reference on the session, it means
	139	* that if we are at the point where we teardown the session, no
	140	* trace belonging to that session exist at this point.
	141	* Calling lttng_ht_destroy in call_rcu worker thread so we
	142	* don't hold the RCU read-side lock while calling it.
	143	*/
	144	lttng_ht_destroy(session->ctf_traces_ht);
5a693d30 MD	145	free(session);
	146	}
	147
2a174661 DG	148	/*
	149	* Delete session from the given hash table.
	150	*
	151	* Return lttng ht del error code being 0 on success and 1 on failure.
	152	*/
5a693d30	153	static int session_delete(struct relay_session *session)
2a174661 DG	154	{
	155	struct lttng_ht_iter iter;
	156
2a174661	157	iter.iter.node = &session->session_n.node;
5a693d30	158	return lttng_ht_del(sessions_ht, &iter);
2a174661 DG	159	}
2a174661 DG	160
5a693d30 MD	161
	162	static void destroy_session(struct relay_session *session)
	163	{
	164	int ret;
	165
	166	ret = session_delete(session);
	167	assert(!ret);
5a693d30 MD	168	call_rcu(&session->rcu_node, rcu_destroy_session);
	169	}
	170
	171	void session_release(struct urcu_ref *ref)
2a174661	172	{
5a693d30 MD	173	struct relay_session *session =
5a693d30 MD	174	caa_container_of(ref, struct relay_session, ref);
2a174661	175
5a693d30 MD	176	destroy_session(session);
5a693d30 MD	177	}
2a174661	178
5a693d30 MD	179	void session_put(struct relay_session *session)
	180	{
	181	rcu_read_lock();
	182	pthread_mutex_lock(&session->reflock);
	183	urcu_ref_put(&session->ref, session_release);
	184	pthread_mutex_unlock(&session->reflock);
	185	rcu_read_unlock();
2a174661 DG	186	}
2a174661 DG	187
5a693d30	188	int session_close(struct relay_session *session)
2a174661 DG	189	{
2a174661 DG	190	int ret = 0;
5a693d30 MD	191	struct ctf_trace *trace;
	192	struct lttng_ht_iter iter;
	193	struct relay_stream *stream;
	194
	195	pthread_mutex_lock(&session->lock);
	196	DBG("closing session %" PRIu64 ": is conn already closed %d",
	197	session->id, session->connection_closed);
	198	if (session->connection_closed) {
	199	ret = -1;
	200	goto unlock;
	201	}
	202	session->connection_closed = true;
	203	unlock:
	204	pthread_mutex_unlock(&session->lock);
	205	if (ret) {
	206	return ret;
	207	}
2a174661	208
5a693d30 MD	209	rcu_read_lock();
	210	cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
	211	&iter.iter, trace, node.node) {
	212	ret = ctf_trace_close(trace);
	213	if (ret) {
	214	goto rcu_unlock;
2a174661 DG	215	}
2a174661 DG	216	}
5a693d30 MD	217	cds_list_for_each_entry_rcu(stream, &session->recv_list,
5a693d30 MD	218	recv_node) {
a08107cc JG	219	/* Close streams which have not been published yet. */
a08107cc JG	220	try_stream_close(stream);
5a693d30 MD	221	}
	222	rcu_unlock:
	223	rcu_read_unlock();
	224	if (ret) {
	225	return ret;
	226	}
	227	/* Put self-reference from create. */
	228	session_put(session);
	229	return ret;
2a174661 DG	230	}
2a174661 DG	231
5a693d30	232	void print_sessions(void)
2a174661	233	{
2a174661	234	struct lttng_ht_iter iter;
5a693d30	235	struct relay_session *session;
2a174661	236
d71e55a5 JG	237	if (!sessions_ht) {
	238	return;
	239	}
	240
2a174661	241	rcu_read_lock();
5a693d30 MD	242	cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
	243	session_n.node) {
	244	if (!session_get(session)) {
	245	continue;
	246	}
	247	DBG("session %p refcount %ld session %" PRIu64,
	248	session,
	249	session->ref.refcount,
	250	session->id);
	251	session_put(session);
2a174661	252	}
2a174661	253	rcu_read_unlock();
2a174661	254	}