[lttng-tools.git] / src / bin / lttng-relayd / viewer-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 "viewer-session.h"
#include "viewer-stream.h"
#include "stream.h"

struct relay_viewer_session *viewer_session_create(void)
{
	struct relay_viewer_session *vsession;

	vsession = zmalloc(sizeof(*vsession));
	if (!vsession) {
		goto end;
	}
	CDS_INIT_LIST_HEAD(&vsession->session_list);
end:
	return vsession;
}

/* The existence of session must be guaranteed by the caller. */
enum lttng_viewer_attach_return_code viewer_session_attach(
		struct relay_viewer_session *vsession,
		struct relay_session *session)
{
	enum lttng_viewer_attach_return_code viewer_attach_status =
			LTTNG_VIEWER_ATTACH_OK;

	ASSERT_LOCKED(session->lock);

	/* Will not fail, as per the ownership guarantee. */
	if (!session_get(session)) {
		viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
		goto end;
	}
	if (session->viewer_attached) {
		viewer_attach_status = LTTNG_VIEWER_ATTACH_ALREADY;
	} else {
		int ret;

		assert(session->current_trace_chunk);
		assert(!vsession->current_trace_chunk);
		session->viewer_attached = true;

		ret = viewer_session_set_trace_chunk(vsession,
				session->current_trace_chunk);
		if (ret) {
			/*
			 * The live protocol does not define a generic error
			 * value for the "attach" command. The "unknown"
			 * status is used so that the viewer may handle this
			 * failure as if the session didn't exist anymore.
			 */
			DBG("Failed to create a viewer trace chunk from the current trace chunk of session \"%s\", returning LTTNG_VIEWER_ATTACH_UNK",
					session->session_name);
			viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
		}
	}

	if (viewer_attach_status == LTTNG_VIEWER_ATTACH_OK) {
		pthread_mutex_lock(&vsession->session_list_lock);
		/* Ownership is transfered to the list. */
		cds_list_add_rcu(&session->viewer_session_node,
				&vsession->session_list);
		pthread_mutex_unlock(&vsession->session_list_lock);
	} else {
		/* Put our local ref. */
		session_put(session);
	}
end:
	return viewer_attach_status;
}

/* The existence of session must be guaranteed by the caller. */
static int viewer_session_detach(struct relay_viewer_session *vsession,
		struct relay_session *session)
{
	int ret = 0;

	pthread_mutex_lock(&session->lock);
	if (!session->viewer_attached) {
		ret = -1;
	} else {
		session->viewer_attached = false;
	}

	if (!ret) {
		pthread_mutex_lock(&vsession->session_list_lock);
		cds_list_del_rcu(&session->viewer_session_node);
		pthread_mutex_unlock(&vsession->session_list_lock);
		/* Release reference held by the list. */
		session_put(session);
	}
	/* Safe since we know the session exists. */
	pthread_mutex_unlock(&session->lock);
	return ret;
}

void viewer_session_destroy(struct relay_viewer_session *vsession)
{
	lttng_trace_chunk_put(vsession->current_trace_chunk);
	free(vsession);
}

/*
 * Release ownership of all the streams of one session and detach the viewer.
 */
void viewer_session_close_one_session(struct relay_viewer_session *vsession,
		struct relay_session *session)
{
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream;

	/*
	 * TODO: improvement: create more efficient list of
	 * vstream per session.
	 */
	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter,
			vstream, stream_n.node) {
		if (!viewer_stream_get(vstream)) {
			continue;
		}
		if (vstream->stream->trace->session != session) {
			viewer_stream_put(vstream);
			continue;
		}
		/* Put local reference. */
		viewer_stream_put(vstream);
		/*
		 * We have reached one of the viewer stream's lifetime
		 * end condition. This "put" will cause the proper
		 * teardown of the viewer stream.
		 */
		viewer_stream_put(vstream);
	}

	viewer_session_detach(vsession, session);
}

void viewer_session_close(struct relay_viewer_session *vsession)
{
	struct relay_session *session;

	rcu_read_lock();
	cds_list_for_each_entry_rcu(session,
			&vsession->session_list, viewer_session_node) {
		viewer_session_close_one_session(vsession, session);
	}
	rcu_read_unlock();
}

/*
 * Check if a connection is attached to a session.
 * Return 1 if attached, 0 if not attached, a negative value on error.
 */
int viewer_session_is_attached(struct relay_viewer_session *vsession,
		struct relay_session *session)
{
	struct relay_session *iter;
	int found = 0;

	pthread_mutex_lock(&session->lock);
	if (!vsession) {
		goto end;
	}
	if (!session->viewer_attached) {
		goto end;
	}
	rcu_read_lock();
	cds_list_for_each_entry_rcu(iter,
			&vsession->session_list,
			viewer_session_node) {
		if (session == iter) {
			found = 1;
			goto end_rcu_unlock;
		}
	}
end_rcu_unlock:
	rcu_read_unlock();
end:
	pthread_mutex_unlock(&session->lock);
	return found;
}

int viewer_session_set_trace_chunk(struct relay_viewer_session *vsession,
		struct lttng_trace_chunk *relay_session_trace_chunk)
{
	int ret = 0;
	struct lttng_trace_chunk *viewer_chunk;

	assert(relay_session_trace_chunk);
	assert(!vsession->current_trace_chunk);

	DBG("Copying relay session's current trace chunk to the viewer session");
	viewer_chunk = lttng_trace_chunk_copy(relay_session_trace_chunk);
	if (!viewer_chunk) {
		ERR("Failed to create a viewer trace chunk from the relay session's current chunk");
		ret = -1;
		goto end;
	}

	vsession->current_trace_chunk = viewer_chunk;
end:
	return ret;
}
Commit	Line	Data
7591bab1 MD	1	/*
	2	* Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
	3	* David Goulet <dgoulet@efficios.com>
	4	* 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	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
7591bab1 MD	20	#define _LGPL_SOURCE
	21	#include <common/common.h>
	22	#include <urcu/rculist.h>
	23
	24	#include "lttng-relayd.h"
	25	#include "ctf-trace.h"
	26	#include "session.h"
	27	#include "viewer-session.h"
	28	#include "viewer-stream.h"
	29	#include "stream.h"
	30
	31	struct relay_viewer_session *viewer_session_create(void)
	32	{
	33	struct relay_viewer_session *vsession;
	34
	35	vsession = zmalloc(sizeof(*vsession));
	36	if (!vsession) {
	37	goto end;
	38	}
	39	CDS_INIT_LIST_HEAD(&vsession->session_list);
	40	end:
	41	return vsession;
	42	}
	43
	44	/* The existence of session must be guaranteed by the caller. */
dbd6665b JG	45	enum lttng_viewer_attach_return_code viewer_session_attach(
dbd6665b JG	46	struct relay_viewer_session *vsession,
7591bab1 MD	47	struct relay_session *session)
7591bab1 MD	48	{
dbd6665b JG	49	enum lttng_viewer_attach_return_code viewer_attach_status =
dbd6665b JG	50	LTTNG_VIEWER_ATTACH_OK;
7591bab1	51
c06fdd95 JG	52	ASSERT_LOCKED(session->lock);
c06fdd95 JG	53
7591bab1 MD	54	/* Will not fail, as per the ownership guarantee. */
7591bab1 MD	55	if (!session_get(session)) {
dbd6665b	56	viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
7591bab1 MD	57	goto end;
7591bab1 MD	58	}
7591bab1	59	if (session->viewer_attached) {
dbd6665b	60	viewer_attach_status = LTTNG_VIEWER_ATTACH_ALREADY;
7591bab1	61	} else {
dbd6665b JG	62	int ret;
	63
	64	assert(session->current_trace_chunk);
	65	assert(!vsession->current_trace_chunk);
7591bab1	66	session->viewer_attached = true;
dbd6665b JG	67
	68	ret = viewer_session_set_trace_chunk(vsession,
	69	session->current_trace_chunk);
	70	if (ret) {
	71	/*
	72	* The live protocol does not define a generic error
	73	* value for the "attach" command. The "unknown"
	74	* status is used so that the viewer may handle this
	75	* failure as if the session didn't exist anymore.
	76	*/
	77	DBG("Failed to create a viewer trace chunk from the current trace chunk of session \"%s\", returning LTTNG_VIEWER_ATTACH_UNK",
	78	session->session_name);
	79	viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK;
	80	}
7591bab1 MD	81	}
7591bab1 MD	82
dbd6665b	83	if (viewer_attach_status == LTTNG_VIEWER_ATTACH_OK) {
7591bab1 MD	84	pthread_mutex_lock(&vsession->session_list_lock);
	85	/* Ownership is transfered to the list. */
	86	cds_list_add_rcu(&session->viewer_session_node,
	87	&vsession->session_list);
	88	pthread_mutex_unlock(&vsession->session_list_lock);
	89	} else {
	90	/* Put our local ref. */
	91	session_put(session);
	92	}
7591bab1	93	end:
dbd6665b	94	return viewer_attach_status;
7591bab1 MD	95	}
	96
	97	/* The existence of session must be guaranteed by the caller. */
	98	static int viewer_session_detach(struct relay_viewer_session *vsession,
	99	struct relay_session *session)
	100	{
	101	int ret = 0;
	102
	103	pthread_mutex_lock(&session->lock);
	104	if (!session->viewer_attached) {
	105	ret = -1;
	106	} else {
	107	session->viewer_attached = false;
	108	}
	109
	110	if (!ret) {
	111	pthread_mutex_lock(&vsession->session_list_lock);
	112	cds_list_del_rcu(&session->viewer_session_node);
	113	pthread_mutex_unlock(&vsession->session_list_lock);
	114	/* Release reference held by the list. */
	115	session_put(session);
	116	}
	117	/* Safe since we know the session exists. */
	118	pthread_mutex_unlock(&session->lock);
	119	return ret;
	120	}
	121
	122	void viewer_session_destroy(struct relay_viewer_session *vsession)
	123	{
b66a15d1	124	lttng_trace_chunk_put(vsession->current_trace_chunk);
7591bab1 MD	125	free(vsession);
	126	}
	127
d62023be JD	128	/*
	129	* Release ownership of all the streams of one session and detach the viewer.
	130	*/
	131	void viewer_session_close_one_session(struct relay_viewer_session *vsession,
	132	struct relay_session *session)
	133	{
	134	struct lttng_ht_iter iter;
	135	struct relay_viewer_stream *vstream;
	136
	137	/*
	138	* TODO: improvement: create more efficient list of
	139	* vstream per session.
	140	*/
	141	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter,
	142	vstream, stream_n.node) {
	143	if (!viewer_stream_get(vstream)) {
	144	continue;
	145	}
	146	if (vstream->stream->trace->session != session) {
	147	viewer_stream_put(vstream);
	148	continue;
	149	}
	150	/* Put local reference. */
	151	viewer_stream_put(vstream);
	152	/*
	153	* We have reached one of the viewer stream's lifetime
	154	* end condition. This "put" will cause the proper
	155	* teardown of the viewer stream.
	156	*/
	157	viewer_stream_put(vstream);
	158	}
	159
	160	viewer_session_detach(vsession, session);
	161	}
	162
7591bab1 MD	163	void viewer_session_close(struct relay_viewer_session *vsession)
	164	{
	165	struct relay_session *session;
	166
	167	rcu_read_lock();
	168	cds_list_for_each_entry_rcu(session,
	169	&vsession->session_list, viewer_session_node) {
d62023be	170	viewer_session_close_one_session(vsession, session);
7591bab1 MD	171	}
	172	rcu_read_unlock();
	173	}
	174
	175	/*
	176	* Check if a connection is attached to a session.
	177	* Return 1 if attached, 0 if not attached, a negative value on error.
	178	*/
	179	int viewer_session_is_attached(struct relay_viewer_session *vsession,
	180	struct relay_session *session)
	181	{
	182	struct relay_session *iter;
	183	int found = 0;
	184
	185	pthread_mutex_lock(&session->lock);
	186	if (!vsession) {
	187	goto end;
	188	}
	189	if (!session->viewer_attached) {
	190	goto end;
	191	}
	192	rcu_read_lock();
	193	cds_list_for_each_entry_rcu(iter,
	194	&vsession->session_list,
	195	viewer_session_node) {
	196	if (session == iter) {
	197	found = 1;
	198	goto end_rcu_unlock;
	199	}
	200	}
	201	end_rcu_unlock:
	202	rcu_read_unlock();
	203	end:
	204	pthread_mutex_unlock(&session->lock);
	205	return found;
	206	}
b66a15d1 JG	207
	208	int viewer_session_set_trace_chunk(struct relay_viewer_session *vsession,
	209	struct lttng_trace_chunk *relay_session_trace_chunk)
	210	{
	211	int ret = 0;
	212	struct lttng_trace_chunk *viewer_chunk;
	213
	214	assert(relay_session_trace_chunk);
	215	assert(!vsession->current_trace_chunk);
	216
	217	DBG("Copying relay session's current trace chunk to the viewer session");
	218	viewer_chunk = lttng_trace_chunk_copy(relay_session_trace_chunk);
	219	if (!viewer_chunk) {
	220	ERR("Failed to create a viewer trace chunk from the relay session's current chunk");
	221	ret = -1;
	222	goto end;
	223	}
	224
	225	vsession->current_trace_chunk = viewer_chunk;
	226	end:
	227	return ret;
	228	}