[lttng-tools.git] / src / bin / lttng-relayd / viewer-stream.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/index/index.h>
#include <common/compat/string.h>
#include <common/utils.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "lttng-relayd.h"
#include "viewer-stream.h"

static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
{
	free(vstream->path_name);
	free(vstream->channel_name);
	free(vstream);
}

static void viewer_stream_destroy_rcu(struct rcu_head *head)
{
	struct relay_viewer_stream *vstream =
		caa_container_of(head, struct relay_viewer_stream, rcu_node);

	viewer_stream_destroy(vstream);
}

struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
		struct lttng_trace_chunk *viewer_trace_chunk,
		enum lttng_viewer_seek seek_t)
{
	struct relay_viewer_stream *vstream = NULL;
	const bool acquired_reference = lttng_trace_chunk_get(
			viewer_trace_chunk);

	if (!acquired_reference) {
		goto error;
	}

	vstream = zmalloc(sizeof(*vstream));
	if (!vstream) {
		PERROR("relay viewer stream zmalloc");
		goto error;
	}

	vstream->stream_file.trace_chunk = viewer_trace_chunk;
	viewer_trace_chunk = NULL;
	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
	if (vstream->path_name == NULL) {
		PERROR("relay viewer path_name alloc");
		goto error;
	}
	vstream->channel_name = lttng_strndup(stream->channel_name,
			LTTNG_VIEWER_NAME_MAX);
	if (vstream->channel_name == NULL) {
		PERROR("relay viewer channel_name alloc");
		goto error;
	}

	if (!stream_get(stream)) {
		ERR("Cannot get stream");
		goto error;
	}
	vstream->stream = stream;

	pthread_mutex_lock(&stream->lock);

	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
		ERR("Cannot attach viewer metadata stream to trace (busy).");
		goto error_unlock;
	}

	switch (seek_t) {
	case LTTNG_VIEWER_SEEK_BEGINNING:
	{
		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);

		if (seq_tail == -1ULL) {
			/*
			 * Tail may not be initialized yet. Nonetheless, we know
			 * we want to send the first index once it becomes
			 * available.
			 */
			seq_tail = 0;
		}
		vstream->current_tracefile_id =
			tracefile_array_get_file_index_tail(stream->tfa);
		vstream->index_sent_seqcount = seq_tail;
		break;
	}
	case LTTNG_VIEWER_SEEK_LAST:
		vstream->current_tracefile_id =
			tracefile_array_get_read_file_index_head(stream->tfa);
		/*
		 * We seek at the very end of each stream, awaiting for
		 * a future packet to eventually come in.
		 *
		 * We don't need to check the head position for -1ULL since the
		 * increment will set it to 0.
		 */
		vstream->index_sent_seqcount =
				tracefile_array_get_seq_head(stream->tfa) + 1;
		break;
	default:
		goto error_unlock;
	}

	/*
	 * If we never received an index for the current stream, delay
	 * the opening of the index, otherwise open it right now.
	 */
	if (stream->index_file == NULL) {
		vstream->index_file = NULL;
	} else {
		const uint32_t connection_major = stream->trace->session->major;
		const uint32_t connection_minor = stream->trace->session->minor;
		enum lttng_trace_chunk_status chunk_status;

		chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
				vstream->stream_file.trace_chunk,
				stream->path_name,
				stream->channel_name, stream->tracefile_size,
				vstream->current_tracefile_id,
				lttng_to_index_major(connection_major,
						connection_minor),
				lttng_to_index_minor(connection_major,
						connection_minor),
				true, &vstream->index_file);
		if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
			if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
				vstream->index_file = NULL;
			} else {
				goto error_unlock;
			}
		}
	}

	/*
	 * If we never received a data file for the current stream, delay the
	 * opening, otherwise open it right now.
	 */
	if (stream->stream_fd) {
		int fd, ret;
		char file_path[LTTNG_PATH_MAX];
		enum lttng_trace_chunk_status status;

		ret = utils_stream_file_path(stream->path_name,
				stream->channel_name, stream->tracefile_size,
				vstream->current_tracefile_id, NULL, file_path,
				sizeof(file_path));
		if (ret < 0) {
			goto error_unlock;
		}

		status = lttng_trace_chunk_open_file(
				vstream->stream_file.trace_chunk,
				file_path, O_RDONLY, 0, &fd, true);
		if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
			goto error_unlock;
		}
		vstream->stream_file.fd = stream_fd_create(fd);
		if (!vstream->stream_file.fd) {
			if (close(fd)) {
				PERROR("Failed to close viewer %sfile",
					stream->is_metadata ? "metadata " : "");
			}
			goto error_unlock;
		}
	}

	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
		off_t lseek_ret;

		lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
		if (lseek_ret < 0) {
			goto error_unlock;
		}
	}
	if (stream->is_metadata) {
		rcu_assign_pointer(stream->trace->viewer_metadata_stream,
				vstream);
	}
	pthread_mutex_unlock(&stream->lock);

	/* Globally visible after the add unique. */
	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
	urcu_ref_init(&vstream->ref);
	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);

	return vstream;

error_unlock:
	pthread_mutex_unlock(&stream->lock);
error:
	if (vstream) {
		viewer_stream_destroy(vstream);
	}
	if (viewer_trace_chunk && acquired_reference) {
		lttng_trace_chunk_put(viewer_trace_chunk);
	}
	return NULL;
}

static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
{
	int ret;
	struct lttng_ht_iter iter;

	iter.iter.node = &vstream->stream_n.node;
	ret = lttng_ht_del(viewer_streams_ht, &iter);
	assert(!ret);
}

static void viewer_stream_release(struct urcu_ref *ref)
{
	struct relay_viewer_stream *vstream = caa_container_of(ref,
			struct relay_viewer_stream, ref);

	if (vstream->stream->is_metadata) {
		rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
	}

	viewer_stream_unpublish(vstream);

	if (vstream->stream_file.fd) {
		stream_fd_put(vstream->stream_file.fd);
		vstream->stream_file.fd = NULL;
	}
	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = NULL;
	}
	if (vstream->stream) {
		stream_put(vstream->stream);
		vstream->stream = NULL;
	}
	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
	vstream->stream_file.trace_chunk = NULL;
	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
}

/* Must be called with RCU read-side lock held. */
bool viewer_stream_get(struct relay_viewer_stream *vstream)
{
	return urcu_ref_get_unless_zero(&vstream->ref);
}

/*
 * Get viewer stream by id.
 *
 * Return viewer stream if found else NULL.
 */
struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
{
	struct lttng_ht_node_u64 *node;
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream = NULL;

	rcu_read_lock();
	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	node = lttng_ht_iter_get_node_u64(&iter);
	if (!node) {
		DBG("Relay viewer stream %" PRIu64 " not found", id);
		goto end;
	}
	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	if (!viewer_stream_get(vstream)) {
		vstream = NULL;
	}
end:
	rcu_read_unlock();
	return vstream;
}

void viewer_stream_put(struct relay_viewer_stream *vstream)
{
	rcu_read_lock();
	urcu_ref_put(&vstream->ref, viewer_stream_release);
	rcu_read_unlock();
}

void viewer_stream_close_files(struct relay_viewer_stream *vstream)
{
	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = NULL;
	}
	if (vstream->stream_file.fd) {
		stream_fd_put(vstream->stream_file.fd);
		vstream->stream_file.fd = NULL;
	}
}

void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
{
	const struct relay_stream *stream = vstream->stream;
	uint64_t seq_tail;

	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
	seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	if (seq_tail == -1ULL) {
		seq_tail = 0;
	}
	vstream->index_sent_seqcount = seq_tail;
}

/*
 * Rotate a stream to the next tracefile.
 *
 * Must be called with the rstream lock held.
 * Returns 0 on success, 1 on EOF.
 */
int viewer_stream_rotate(struct relay_viewer_stream *vstream)
{
	int ret;
	uint64_t new_id;
	const struct relay_stream *stream = vstream->stream;

	/* Detect the last tracefile to open. */
	if (stream->index_received_seqcount
			== vstream->index_sent_seqcount
			&& stream->trace->session->connection_closed) {
		ret = 1;
		goto end;
	}

	if (stream->tracefile_count == 0) {
		/* Ignore rotation, there is none to do. */
		ret = 0;
		goto end;
	}

	/*
	 * Try to move to the next file.
	 */
	new_id = (vstream->current_tracefile_id + 1)
			% stream->tracefile_count;
	if (tracefile_array_seq_in_file(stream->tfa, new_id,
			vstream->index_sent_seqcount)) {
		vstream->current_tracefile_id = new_id;
	} else {
		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);

		/*
		 * This can only be reached on overwrite, which implies there
		 * has been data written at some point, which will have set the
		 * tail.
		 */
		assert(seq_tail != -1ULL);
		/*
		 * We need to resync because we lag behind tail.
		 */
		vstream->current_tracefile_id =
			tracefile_array_get_file_index_tail(stream->tfa);
		vstream->index_sent_seqcount = seq_tail;
	}
	viewer_stream_close_files(vstream);
	ret = 0;
end:
	return ret;
}

void print_viewer_streams(void)
{
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream;

	if (!viewer_streams_ht) {
		return;
	}

	rcu_read_lock();
	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
			stream_n.node) {
		if (!viewer_stream_get(vstream)) {
			continue;
		}
		DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
			" session %" PRIu64,
			vstream,
			vstream->ref.refcount,
			vstream->stream->stream_handle,
			vstream->stream->trace->id,
			vstream->stream->trace->session->id);
		viewer_stream_put(vstream);
	}
	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
2f8f53af DG	21	#include <common/common.h>
2f8f53af DG	22	#include <common/index/index.h>
f5436bfc	23	#include <common/compat/string.h>
b0d240a2 MD	24	#include <common/utils.h>
	25	#include <sys/types.h>
	26	#include <sys/stat.h>
	27	#include <fcntl.h>
2f8f53af DG	28
	29	#include "lttng-relayd.h"
	30	#include "viewer-stream.h"
	31
7591bab1	32	static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
2f8f53af	33	{
7591bab1 MD	34	free(vstream->path_name);
	35	free(vstream->channel_name);
	36	free(vstream);
2f8f53af DG	37	}
2f8f53af DG	38
7591bab1	39	static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af	40	{
7591bab1	41	struct relay_viewer_stream *vstream =
2f8f53af DG	42	caa_container_of(head, struct relay_viewer_stream, rcu_node);
2f8f53af DG	43
7591bab1	44	viewer_stream_destroy(vstream);
2f8f53af DG	45	}
	46
	47	struct relay_viewer_stream viewer_stream_create(struct relay_stream stream,
b66a15d1	48	struct lttng_trace_chunk *viewer_trace_chunk,
7591bab1	49	enum lttng_viewer_seek seek_t)
2f8f53af	50	{
ebb29c10 JG	51	struct relay_viewer_stream *vstream = NULL;
ebb29c10 JG	52	const bool acquired_reference = lttng_trace_chunk_get(
b66a15d1	53	viewer_trace_chunk);
ebb29c10 JG	54
	55	if (!acquired_reference) {
	56	goto error;
	57	}
2f8f53af	58
2f8f53af DG	59	vstream = zmalloc(sizeof(*vstream));
	60	if (!vstream) {
	61	PERROR("relay viewer stream zmalloc");
	62	goto error;
	63	}
	64
b66a15d1 JG	65	vstream->stream_file.trace_chunk = viewer_trace_chunk;
b66a15d1 JG	66	viewer_trace_chunk = NULL;
f5436bfc	67	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
b272577e MD	68	if (vstream->path_name == NULL) {
	69	PERROR("relay viewer path_name alloc");
	70	goto error;
	71	}
f5436bfc	72	vstream->channel_name = lttng_strndup(stream->channel_name,
2f8f53af	73	LTTNG_VIEWER_NAME_MAX);
b272577e MD	74	if (vstream->channel_name == NULL) {
	75	PERROR("relay viewer channel_name alloc");
	76	goto error;
	77	}
2f8f53af	78
a44ca2ca MD	79	if (!stream_get(stream)) {
	80	ERR("Cannot get stream");
	81	goto error;
	82	}
	83	vstream->stream = stream;
	84
	85	pthread_mutex_lock(&stream->lock);
	86
	87	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
	88	ERR("Cannot attach viewer metadata stream to trace (busy).");
	89	goto error_unlock;
	90	}
	91
2f8f53af	92	switch (seek_t) {
c4e361a4	93	case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca MD	94	{
	95	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	96
	97	if (seq_tail == -1ULL) {
	98	/*
	99	* Tail may not be initialized yet. Nonetheless, we know
	100	* we want to send the first index once it becomes
	101	* available.
	102	*/
	103	seq_tail = 0;
	104	}
	105	vstream->current_tracefile_id =
	106	tracefile_array_get_file_index_tail(stream->tfa);
	107	vstream->index_sent_seqcount = seq_tail;
2f8f53af	108	break;
a44ca2ca	109	}
c4e361a4	110	case LTTNG_VIEWER_SEEK_LAST:
a44ca2ca	111	vstream->current_tracefile_id =
78118e3b	112	tracefile_array_get_read_file_index_head(stream->tfa);
a44ca2ca MD	113	/*
	114	* We seek at the very end of each stream, awaiting for
	115	* a future packet to eventually come in.
	116	*
	117	* We don't need to check the head position for -1ULL since the
	118	* increment will set it to 0.
	119	*/
	120	vstream->index_sent_seqcount =
	121	tracefile_array_get_seq_head(stream->tfa) + 1;
2f8f53af DG	122	break;
2f8f53af DG	123	default:
a44ca2ca	124	goto error_unlock;
2f8f53af	125	}
2f8f53af	126
2f8f53af	127	/*
a44ca2ca MD	128	* If we never received an index for the current stream, delay
a44ca2ca MD	129	* the opening of the index, otherwise open it right now.
2f8f53af	130	*/
b0d240a2	131	if (stream->index_file == NULL) {
f8f3885c	132	vstream->index_file = NULL;
2f8f53af	133	} else {
ebb29c10 JG	134	const uint32_t connection_major = stream->trace->session->major;
ebb29c10 JG	135	const uint32_t connection_minor = stream->trace->session->minor;
3ff5c5db	136	enum lttng_trace_chunk_status chunk_status;
ebb29c10	137
3ff5c5db	138	chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
b66a15d1 JG	139	vstream->stream_file.trace_chunk,
b66a15d1 JG	140	stream->path_name,
ebb29c10 JG	141	stream->channel_name, stream->tracefile_size,
	142	vstream->current_tracefile_id,
	143	lttng_to_index_major(connection_major,
	144	connection_minor),
	145	lttng_to_index_minor(connection_major,
3ff5c5db MD	146	connection_minor),
	147	true, &vstream->index_file);
	148	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	149	if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
	150	vstream->index_file = NULL;
	151	} else {
	152	goto error_unlock;
	153	}
2f8f53af	154	}
2f8f53af DG	155	}
2f8f53af DG	156
b0d240a2 MD	157	/*
	158	* If we never received a data file for the current stream, delay the
	159	* opening, otherwise open it right now.
	160	*/
	161	if (stream->stream_fd) {
	162	int fd, ret;
	163	char file_path[LTTNG_PATH_MAX];
	164	enum lttng_trace_chunk_status status;
	165
	166	ret = utils_stream_file_path(stream->path_name,
	167	stream->channel_name, stream->tracefile_size,
	168	vstream->current_tracefile_id, NULL, file_path,
	169	sizeof(file_path));
	170	if (ret < 0) {
	171	goto error_unlock;
	172	}
	173
	174	status = lttng_trace_chunk_open_file(
	175	vstream->stream_file.trace_chunk,
	176	file_path, O_RDONLY, 0, &fd, true);
	177	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	178	goto error_unlock;
	179	}
	180	vstream->stream_file.fd = stream_fd_create(fd);
	181	if (!vstream->stream_file.fd) {
	182	if (close(fd)) {
	183	PERROR("Failed to close viewer %sfile",
	184	stream->is_metadata ? "metadata " : "");
	185	}
	186	goto error_unlock;
	187	}
	188	}
	189
f8f3885c	190	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
2f8f53af DG	191	off_t lseek_ret;
2f8f53af DG	192
f8f3885c	193	lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
2f8f53af	194	if (lseek_ret < 0) {
7591bab1	195	goto error_unlock;
2f8f53af	196	}
7591bab1	197	}
7591bab1 MD	198	if (stream->is_metadata) {
	199	rcu_assign_pointer(stream->trace->viewer_metadata_stream,
	200	vstream);
2f8f53af	201	}
a44ca2ca	202	pthread_mutex_unlock(&stream->lock);
2f8f53af	203
7591bab1 MD	204	/* Globally visible after the add unique. */
7591bab1 MD	205	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
7591bab1	206	urcu_ref_init(&vstream->ref);
c51b2177	207	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
7591bab1	208
2f8f53af DG	209	return vstream;
2f8f53af DG	210
7591bab1 MD	211	error_unlock:
7591bab1 MD	212	pthread_mutex_unlock(&stream->lock);
2f8f53af DG	213	error:
2f8f53af DG	214	if (vstream) {
7591bab1	215	viewer_stream_destroy(vstream);
2f8f53af	216	}
e4650a96	217	if (viewer_trace_chunk && acquired_reference) {
b66a15d1 JG	218	lttng_trace_chunk_put(viewer_trace_chunk);
b66a15d1 JG	219	}
2f8f53af DG	220	return NULL;
	221	}
	222
7591bab1	223	static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
2f8f53af DG	224	{
	225	int ret;
	226	struct lttng_ht_iter iter;
	227
7591bab1	228	iter.iter.node = &vstream->stream_n.node;
2f8f53af DG	229	ret = lttng_ht_del(viewer_streams_ht, &iter);
	230	assert(!ret);
	231	}
	232
7591bab1	233	static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af	234	{
7591bab1 MD	235	struct relay_viewer_stream *vstream = caa_container_of(ref,
7591bab1 MD	236	struct relay_viewer_stream, ref);
2a174661	237
7591bab1 MD	238	if (vstream->stream->is_metadata) {
7591bab1 MD	239	rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661	240	}
2f8f53af	241
7591bab1 MD	242	viewer_stream_unpublish(vstream);
7591bab1 MD	243
ebb29c10 JG	244	if (vstream->stream_file.fd) {
	245	stream_fd_put(vstream->stream_file.fd);
	246	vstream->stream_file.fd = NULL;
2f8f53af	247	}
f8f3885c MD	248	if (vstream->index_file) {
	249	lttng_index_file_put(vstream->index_file);
	250	vstream->index_file = NULL;
7591bab1 MD	251	}
	252	if (vstream->stream) {
	253	stream_put(vstream->stream);
	254	vstream->stream = NULL;
	255	}
4c2717fc JG	256	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
4c2717fc JG	257	vstream->stream_file.trace_chunk = NULL;
7591bab1 MD	258	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
	259	}
	260
	261	/* Must be called with RCU read-side lock held. */
	262	bool viewer_stream_get(struct relay_viewer_stream *vstream)
	263	{
ce4d4083	264	return urcu_ref_get_unless_zero(&vstream->ref);
2f8f53af DG	265	}
	266
	267	/*
7591bab1	268	* Get viewer stream by id.
2f8f53af	269	*
7591bab1	270	* Return viewer stream if found else NULL.
2f8f53af	271	*/
7591bab1	272	struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
2f8f53af DG	273	{
	274	struct lttng_ht_node_u64 *node;
	275	struct lttng_ht_iter iter;
7591bab1	276	struct relay_viewer_stream *vstream = NULL;
2f8f53af	277
7591bab1	278	rcu_read_lock();
2f8f53af DG	279	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	280	node = lttng_ht_iter_get_node_u64(&iter);
	281	if (!node) {
	282	DBG("Relay viewer stream %" PRIu64 " not found", id);
	283	goto end;
	284	}
7591bab1 MD	285	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	286	if (!viewer_stream_get(vstream)) {
	287	vstream = NULL;
	288	}
2f8f53af	289	end:
7591bab1 MD	290	rcu_read_unlock();
	291	return vstream;
	292	}
	293
	294	void viewer_stream_put(struct relay_viewer_stream *vstream)
	295	{
	296	rcu_read_lock();
7591bab1	297	urcu_ref_put(&vstream->ref, viewer_stream_release);
7591bab1 MD	298	rcu_read_unlock();
	299	}
	300
3087b021 MD	301	void viewer_stream_close_files(struct relay_viewer_stream *vstream)
	302	{
	303	if (vstream->index_file) {
	304	lttng_index_file_put(vstream->index_file);
	305	vstream->index_file = NULL;
	306	}
	307	if (vstream->stream_file.fd) {
	308	stream_fd_put(vstream->stream_file.fd);
	309	vstream->stream_file.fd = NULL;
	310	}
	311	}
	312
	313	void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
	314	{
	315	const struct relay_stream *stream = vstream->stream;
	316	uint64_t seq_tail;
	317
	318	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
	319	seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	320	if (seq_tail == -1ULL) {
	321	seq_tail = 0;
	322	}
	323	vstream->index_sent_seqcount = seq_tail;
	324	}
	325
2f8f53af DG	326	/*
	327	* Rotate a stream to the next tracefile.
	328	*
7591bab1	329	* Must be called with the rstream lock held.
b0d240a2	330	* Returns 0 on success, 1 on EOF.
2f8f53af	331	*/
7591bab1	332	int viewer_stream_rotate(struct relay_viewer_stream *vstream)
2f8f53af DG	333	{
2f8f53af DG	334	int ret;
a44ca2ca	335	uint64_t new_id;
ebb29c10	336	const struct relay_stream *stream = vstream->stream;
2f8f53af	337
7591bab1	338	/* Detect the last tracefile to open. */
a44ca2ca MD	339	if (stream->index_received_seqcount
a44ca2ca MD	340	== vstream->index_sent_seqcount
7591bab1 MD	341	&& stream->trace->session->connection_closed) {
7591bab1 MD	342	ret = 1;
2a174661 DG	343	goto end;
2a174661 DG	344	}
2f8f53af	345
7591bab1 MD	346	if (stream->tracefile_count == 0) {
	347	/* Ignore rotation, there is none to do. */
	348	ret = 0;
2f8f53af DG	349	goto end;
	350	}
	351
a44ca2ca MD	352	/*
	353	* Try to move to the next file.
	354	*/
	355	new_id = (vstream->current_tracefile_id + 1)
	356	% stream->tracefile_count;
	357	if (tracefile_array_seq_in_file(stream->tfa, new_id,
	358	vstream->index_sent_seqcount)) {
	359	vstream->current_tracefile_id = new_id;
2f8f53af	360	} else {
a44ca2ca MD	361	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	362
	363	/*
	364	* This can only be reached on overwrite, which implies there
	365	* has been data written at some point, which will have set the
	366	* tail.
	367	*/
	368	assert(seq_tail != -1ULL);
	369	/*
	370	* We need to resync because we lag behind tail.
	371	*/
7591bab1	372	vstream->current_tracefile_id =
a44ca2ca MD	373	tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca MD	374	vstream->index_sent_seqcount = seq_tail;
2f8f53af	375	}
b0d240a2 MD	376	viewer_stream_close_files(vstream);
b0d240a2 MD	377	ret = 0;
2f8f53af	378	end:
2f8f53af DG	379	return ret;
2f8f53af DG	380	}
7591bab1 MD	381
	382	void print_viewer_streams(void)
	383	{
	384	struct lttng_ht_iter iter;
	385	struct relay_viewer_stream *vstream;
	386
ce3f3ba3 JG	387	if (!viewer_streams_ht) {
	388	return;
	389	}
	390
7591bab1 MD	391	rcu_read_lock();
	392	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
	393	stream_n.node) {
	394	if (!viewer_stream_get(vstream)) {
	395	continue;
	396	}
	397	DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
	398	" session %" PRIu64,
	399	vstream,
	400	vstream->ref.refcount,
	401	vstream->stream->stream_handle,
	402	vstream->stream->trace->id,
	403	vstream->stream->trace->session->id);
	404	viewer_stream_put(vstream);
	405	}
	406	rcu_read_unlock();
	407	}