[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 <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>
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>
7591bab1	22	#include <urcu/rculist.h>
2a174661	23
7591bab1	24	#include "lttng-relayd.h"
2a174661	25	#include "ctf-trace.h"
2f8f53af	26	#include "session.h"
2a174661 DG	27	#include "stream.h"
	28
	29	/* Global session id used in the session creation. */
	30	static uint64_t last_relay_session_id;
7591bab1	31	static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
2a174661 DG	32
	33	/*
	34	* Create a new session by assigning a new session ID.
	35	*
	36	* Return allocated session or else NULL.
	37	*/
7591bab1 MD	38	struct relay_session session_create(const char session_name,
	39	const char *hostname, uint32_t live_timer,
	40	bool snapshot, uint32_t major, uint32_t minor)
2a174661 DG	41	{
	42	struct relay_session *session;
	43
	44	session = zmalloc(sizeof(*session));
	45	if (!session) {
	46	PERROR("relay session zmalloc");
	47	goto error;
	48	}
bb5d54e7 MD	49	if (lttng_strncpy(session->session_name, session_name,
	50	sizeof(session->session_name))) {
	51	goto error;
	52	}
	53	if (lttng_strncpy(session->hostname, hostname,
	54	sizeof(session->hostname))) {
	55	goto error;
	56	}
2a174661 DG	57	session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
2a174661 DG	58	if (!session->ctf_traces_ht) {
2a174661 DG	59	goto error;
	60	}
	61
7591bab1	62	pthread_mutex_lock(&last_relay_session_id_lock);
2a174661	63	session->id = ++last_relay_session_id;
7591bab1 MD	64	pthread_mutex_unlock(&last_relay_session_id_lock);
	65
	66	session->major = major;
	67	session->minor = minor;
2a174661	68	lttng_ht_node_init_u64(&session->session_n, session->id);
7591bab1 MD	69	urcu_ref_init(&session->ref);
	70	CDS_INIT_LIST_HEAD(&session->recv_list);
	71	pthread_mutex_init(&session->lock, NULL);
	72	pthread_mutex_init(&session->reflock, NULL);
	73	pthread_mutex_init(&session->recv_list_lock, NULL);
	74
7591bab1 MD	75	session->live_timer = live_timer;
	76	session->snapshot = snapshot;
	77
	78	lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
bb5d54e7	79	return session;
2a174661 DG	80
2a174661 DG	81	error:
bb5d54e7 MD	82	free(session);
bb5d54e7 MD	83	return NULL;
2a174661	84	}
2f8f53af	85
7591bab1 MD	86	/* Should be called with RCU read-side lock held. */
	87	bool session_get(struct relay_session *session)
	88	{
	89	bool has_ref = false;
	90
	91	pthread_mutex_lock(&session->reflock);
	92	if (session->ref.refcount != 0) {
	93	has_ref = true;
	94	urcu_ref_get(&session->ref);
	95	}
	96	pthread_mutex_unlock(&session->reflock);
	97
	98	return has_ref;
	99	}
	100
2f8f53af	101	/*
7591bab1 MD	102	* Lookup a session within the session hash table using the session id
	103	* as key. A session reference is taken when a session is returned.
	104	* session_put() must be called on that session.
2f8f53af DG	105	*
	106	* Return session or NULL if not found.
	107	*/
7591bab1	108	struct relay_session *session_get_by_id(uint64_t id)
2f8f53af DG	109	{
2f8f53af DG	110	struct relay_session *session = NULL;
2a174661	111	struct lttng_ht_node_u64 *node;
2f8f53af DG	112	struct lttng_ht_iter iter;
2f8f53af DG	113
7591bab1 MD	114	rcu_read_lock();
7591bab1 MD	115	lttng_ht_lookup(sessions_ht, &id, &iter);
2a174661	116	node = lttng_ht_iter_get_node_u64(&iter);
2f8f53af	117	if (!node) {
2a174661	118	DBG("Session find by ID %" PRIu64 " id NOT found", id);
2f8f53af DG	119	goto end;
	120	}
	121	session = caa_container_of(node, struct relay_session, session_n);
2a174661	122	DBG("Session find by ID %" PRIu64 " id found", id);
7591bab1 MD	123	if (!session_get(session)) {
	124	session = NULL;
	125	}
2f8f53af	126	end:
7591bab1	127	rcu_read_unlock();
2f8f53af DG	128	return session;
2f8f53af DG	129	}
2a174661	130
7591bab1 MD	131	static void rcu_destroy_session(struct rcu_head *rcu_head)
	132	{
	133	struct relay_session *session =
	134	caa_container_of(rcu_head, struct relay_session,
	135	rcu_node);
49e614cb MD	136	/*
	137	* Since each trace has a reference on the session, it means
	138	* that if we are at the point where we teardown the session, no
	139	* trace belonging to that session exist at this point.
	140	* Calling lttng_ht_destroy in call_rcu worker thread so we
	141	* don't hold the RCU read-side lock while calling it.
	142	*/
	143	lttng_ht_destroy(session->ctf_traces_ht);
7591bab1 MD	144	free(session);
	145	}
	146
2a174661 DG	147	/*
	148	* Delete session from the given hash table.
	149	*
	150	* Return lttng ht del error code being 0 on success and 1 on failure.
	151	*/
7591bab1	152	static int session_delete(struct relay_session *session)
2a174661 DG	153	{
	154	struct lttng_ht_iter iter;
	155
2a174661	156	iter.iter.node = &session->session_n.node;
7591bab1	157	return lttng_ht_del(sessions_ht, &iter);
2a174661 DG	158	}
2a174661 DG	159
7591bab1 MD	160
	161	static void destroy_session(struct relay_session *session)
	162	{
	163	int ret;
	164
	165	ret = session_delete(session);
	166	assert(!ret);
7591bab1 MD	167	call_rcu(&session->rcu_node, rcu_destroy_session);
	168	}
	169
	170	void session_release(struct urcu_ref *ref)
2a174661	171	{
7591bab1 MD	172	struct relay_session *session =
7591bab1 MD	173	caa_container_of(ref, struct relay_session, ref);
2a174661	174
7591bab1 MD	175	destroy_session(session);
7591bab1 MD	176	}
2a174661	177
7591bab1 MD	178	void session_put(struct relay_session *session)
	179	{
	180	rcu_read_lock();
	181	pthread_mutex_lock(&session->reflock);
	182	urcu_ref_put(&session->ref, session_release);
	183	pthread_mutex_unlock(&session->reflock);
	184	rcu_read_unlock();
2a174661 DG	185	}
2a174661 DG	186
7591bab1	187	int session_close(struct relay_session *session)
2a174661 DG	188	{
2a174661 DG	189	int ret = 0;
7591bab1 MD	190	struct ctf_trace *trace;
	191	struct lttng_ht_iter iter;
	192	struct relay_stream *stream;
	193
	194	pthread_mutex_lock(&session->lock);
	195	DBG("closing session %" PRIu64 ": is conn already closed %d",
	196	session->id, session->connection_closed);
	197	if (session->connection_closed) {
	198	ret = -1;
	199	goto unlock;
	200	}
	201	session->connection_closed = true;
	202	unlock:
	203	pthread_mutex_unlock(&session->lock);
	204	if (ret) {
	205	return ret;
	206	}
2a174661	207
7591bab1 MD	208	rcu_read_lock();
	209	cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
	210	&iter.iter, trace, node.node) {
	211	ret = ctf_trace_close(trace);
	212	if (ret) {
	213	goto rcu_unlock;
2a174661 DG	214	}
2a174661 DG	215	}
7591bab1 MD	216	cds_list_for_each_entry_rcu(stream, &session->recv_list,
7591bab1 MD	217	recv_node) {
bda7c7b9 JG	218	/* Close streams which have not been published yet. */
bda7c7b9 JG	219	try_stream_close(stream);
7591bab1 MD	220	}
	221	rcu_unlock:
	222	rcu_read_unlock();
	223	if (ret) {
	224	return ret;
	225	}
	226	/* Put self-reference from create. */
	227	session_put(session);
	228	return ret;
2a174661 DG	229	}
2a174661 DG	230
7591bab1	231	void print_sessions(void)
2a174661	232	{
2a174661	233	struct lttng_ht_iter iter;
7591bab1	234	struct relay_session *session;
2a174661	235
ce3f3ba3 JG	236	if (!sessions_ht) {
	237	return;
	238	}
	239
2a174661	240	rcu_read_lock();
7591bab1 MD	241	cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
	242	session_n.node) {
	243	if (!session_get(session)) {
	244	continue;
	245	}
	246	DBG("session %p refcount %ld session %" PRIu64,
	247	session,
	248	session->ref.refcount,
	249	session->id);
	250	session_put(session);
2a174661	251	}
2a174661	252	rcu_read_unlock();
2a174661	253	}