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

/*
 * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
 * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#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_release_composite_objects(struct relay_viewer_stream *vstream)
{
	if (vstream->stream_file.handle) {
		fs_handle_close(vstream->stream_file.handle);
		vstream->stream_file.handle = 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;
}

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);
}

/* Relay stream's lock must be held by the caller. */
struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
		struct lttng_trace_chunk *trace_chunk,
		enum lttng_viewer_seek seek_t)
{
	struct relay_viewer_stream *vstream = NULL;

	ASSERT_LOCKED(stream->lock);

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

	if (trace_chunk) {
		const bool acquired_reference = lttng_trace_chunk_get(
				trace_chunk);

		assert(acquired_reference);
	}

	vstream->stream_file.trace_chunk = trace_chunk;
	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;

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

	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;
	}

	/*
	 * 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;
			}
		}
	}

	/*
	 * If we never received a data file for the current stream, delay the
	 * opening, otherwise open it right now.
	 */
	if (stream->file) {
		int 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;
		}

		status = lttng_trace_chunk_open_fs_handle(
				vstream->stream_file.trace_chunk, file_path,
				O_RDONLY, 0, &vstream->stream_file.handle,
				true);
		if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
			goto error;
		}
	}

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

		lseek_ret = fs_handle_seek(
				vstream->index_file->file, 0, SEEK_END);
		if (lseek_ret < 0) {
			goto error;
		}
	}
	if (stream->is_metadata) {
		rcu_assign_pointer(stream->trace->viewer_metadata_stream,
				vstream);
	}

	vstream->last_seen_rotation_count = stream->completed_rotation_count;

	/* 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:
	if (vstream) {
		/* Not using `put` since vstream is assumed to be published. */
		viewer_stream_release_composite_objects(vstream);
		viewer_stream_destroy(vstream);
	}
	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);
	viewer_stream_release_composite_objects(vstream);
	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.handle) {
	        fs_handle_close(vstream->stream_file.handle);
		vstream->stream_file.handle = 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;
	}

	/*
	 * Move the index sent seqcount forward if it was lagging behind
	 * the new tail of the tracefile array. If the current
	 * index_sent_seqcount is already further than the tracefile
	 * array tail position, keep its current position.
	 */
	vstream->index_sent_seqcount = seq_tail > vstream->index_sent_seqcount ?
			seq_tail : vstream->index_sent_seqcount;
}

/*
 * 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	1	/*
ab5be9fa MJ	2	* Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
	3	* Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
	4	* Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2f8f53af	5	*
ab5be9fa	6	* SPDX-License-Identifier: GPL-2.0-only
2f8f53af	7	*
2f8f53af DG	8	*/
2f8f53af DG	9
6c1c0768	10	#define _LGPL_SOURCE
2f8f53af DG	11	#include <common/common.h>
2f8f53af DG	12	#include <common/index/index.h>
f5436bfc	13	#include <common/compat/string.h>
b0d240a2 MD	14	#include <common/utils.h>
	15	#include <sys/types.h>
	16	#include <sys/stat.h>
	17	#include <fcntl.h>
2f8f53af DG	18
	19	#include "lttng-relayd.h"
	20	#include "viewer-stream.h"
	21
0f31e182	22	static void viewer_stream_release_composite_objects(struct relay_viewer_stream *vstream)
2f8f53af	23	{
0f31e182 MD	24	if (vstream->stream_file.handle) {
	25	fs_handle_close(vstream->stream_file.handle);
	26	vstream->stream_file.handle = NULL;
	27	}
	28	if (vstream->index_file) {
	29	lttng_index_file_put(vstream->index_file);
	30	vstream->index_file = NULL;
	31	}
	32	if (vstream->stream) {
	33	stream_put(vstream->stream);
	34	vstream->stream = NULL;
	35	}
eca8e6d9	36	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
0f31e182 MD	37	vstream->stream_file.trace_chunk = NULL;
	38	}
	39
	40	static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
	41	{
7591bab1 MD	42	free(vstream->path_name);
	43	free(vstream->channel_name);
	44	free(vstream);
2f8f53af DG	45	}
2f8f53af DG	46
7591bab1	47	static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af	48	{
7591bab1	49	struct relay_viewer_stream *vstream =
2f8f53af DG	50	caa_container_of(head, struct relay_viewer_stream, rcu_node);
2f8f53af DG	51
7591bab1	52	viewer_stream_destroy(vstream);
2f8f53af DG	53	}
2f8f53af DG	54
e69067f2	55	/* Relay stream's lock must be held by the caller. */
2f8f53af	56	struct relay_viewer_stream viewer_stream_create(struct relay_stream stream,
e69067f2	57	struct lttng_trace_chunk *trace_chunk,
7591bab1	58	enum lttng_viewer_seek seek_t)
2f8f53af	59	{
ebb29c10	60	struct relay_viewer_stream *vstream = NULL;
ebb29c10	61
e69067f2	62	ASSERT_LOCKED(stream->lock);
2f8f53af	63
2f8f53af DG	64	vstream = zmalloc(sizeof(*vstream));
	65	if (!vstream) {
	66	PERROR("relay viewer stream zmalloc");
	67	goto error;
	68	}
	69
eca8e6d9 JG	70	if (trace_chunk) {
	71	const bool acquired_reference = lttng_trace_chunk_get(
	72	trace_chunk);
	73
	74	assert(acquired_reference);
	75	}
	76
e69067f2	77	vstream->stream_file.trace_chunk = trace_chunk;
f5436bfc	78	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
b272577e MD	79	if (vstream->path_name == NULL) {
	80	PERROR("relay viewer path_name alloc");
	81	goto error;
	82	}
f5436bfc	83	vstream->channel_name = lttng_strndup(stream->channel_name,
2f8f53af	84	LTTNG_VIEWER_NAME_MAX);
b272577e MD	85	if (vstream->channel_name == NULL) {
	86	PERROR("relay viewer channel_name alloc");
	87	goto error;
	88	}
2f8f53af	89
a44ca2ca MD	90	if (!stream_get(stream)) {
	91	ERR("Cannot get stream");
	92	goto error;
	93	}
	94	vstream->stream = stream;
	95
a44ca2ca MD	96	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
a44ca2ca MD	97	ERR("Cannot attach viewer metadata stream to trace (busy).");
a1c672ba	98	goto error;
a44ca2ca MD	99	}
a44ca2ca MD	100
2f8f53af	101	switch (seek_t) {
c4e361a4	102	case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca MD	103	{
	104	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	105
	106	if (seq_tail == -1ULL) {
	107	/*
	108	* Tail may not be initialized yet. Nonetheless, we know
	109	* we want to send the first index once it becomes
	110	* available.
	111	*/
	112	seq_tail = 0;
	113	}
	114	vstream->current_tracefile_id =
	115	tracefile_array_get_file_index_tail(stream->tfa);
	116	vstream->index_sent_seqcount = seq_tail;
2f8f53af	117	break;
a44ca2ca	118	}
c4e361a4	119	case LTTNG_VIEWER_SEEK_LAST:
a44ca2ca	120	vstream->current_tracefile_id =
78118e3b	121	tracefile_array_get_read_file_index_head(stream->tfa);
a44ca2ca MD	122	/*
	123	* We seek at the very end of each stream, awaiting for
	124	* a future packet to eventually come in.
	125	*
	126	* We don't need to check the head position for -1ULL since the
	127	* increment will set it to 0.
	128	*/
	129	vstream->index_sent_seqcount =
	130	tracefile_array_get_seq_head(stream->tfa) + 1;
2f8f53af DG	131	break;
2f8f53af DG	132	default:
a1c672ba	133	goto error;
2f8f53af	134	}
2f8f53af	135
2f8f53af	136	/*
a44ca2ca MD	137	* If we never received an index for the current stream, delay
a44ca2ca MD	138	* the opening of the index, otherwise open it right now.
2f8f53af	139	*/
b0d240a2	140	if (stream->index_file == NULL) {
f8f3885c	141	vstream->index_file = NULL;
2f8f53af	142	} else {
ebb29c10 JG	143	const uint32_t connection_major = stream->trace->session->major;
ebb29c10 JG	144	const uint32_t connection_minor = stream->trace->session->minor;
3ff5c5db	145	enum lttng_trace_chunk_status chunk_status;
ebb29c10	146
3ff5c5db	147	chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
b66a15d1 JG	148	vstream->stream_file.trace_chunk,
b66a15d1 JG	149	stream->path_name,
ebb29c10 JG	150	stream->channel_name, stream->tracefile_size,
	151	vstream->current_tracefile_id,
	152	lttng_to_index_major(connection_major,
	153	connection_minor),
	154	lttng_to_index_minor(connection_major,
3ff5c5db MD	155	connection_minor),
	156	true, &vstream->index_file);
	157	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	158	if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
	159	vstream->index_file = NULL;
	160	} else {
a1c672ba	161	goto error;
3ff5c5db	162	}
2f8f53af	163	}
2f8f53af DG	164	}
2f8f53af DG	165
b0d240a2 MD	166	/*
	167	* If we never received a data file for the current stream, delay the
	168	* opening, otherwise open it right now.
	169	*/
8bb66c3c JG	170	if (stream->file) {
8bb66c3c JG	171	int ret;
b0d240a2 MD	172	char file_path[LTTNG_PATH_MAX];
	173	enum lttng_trace_chunk_status status;
	174
	175	ret = utils_stream_file_path(stream->path_name,
	176	stream->channel_name, stream->tracefile_size,
	177	vstream->current_tracefile_id, NULL, file_path,
	178	sizeof(file_path));
	179	if (ret < 0) {
a1c672ba	180	goto error;
b0d240a2 MD	181	}
b0d240a2 MD	182
8bb66c3c JG	183	status = lttng_trace_chunk_open_fs_handle(
	184	vstream->stream_file.trace_chunk, file_path,
	185	O_RDONLY, 0, &vstream->stream_file.handle,
	186	true);
b0d240a2	187	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
a1c672ba	188	goto error;
b0d240a2	189	}
b0d240a2 MD	190	}
b0d240a2 MD	191
f8f3885c	192	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
2f8f53af DG	193	off_t lseek_ret;
2f8f53af DG	194
8bb66c3c JG	195	lseek_ret = fs_handle_seek(
8bb66c3c JG	196	vstream->index_file->file, 0, SEEK_END);
2f8f53af	197	if (lseek_ret < 0) {
a1c672ba	198	goto error;
2f8f53af	199	}
7591bab1	200	}
7591bab1 MD	201	if (stream->is_metadata) {
	202	rcu_assign_pointer(stream->trace->viewer_metadata_stream,
	203	vstream);
2f8f53af DG	204	}
2f8f53af DG	205
eca8e6d9 JG	206	vstream->last_seen_rotation_count = stream->completed_rotation_count;
eca8e6d9 JG	207
7591bab1 MD	208	/* Globally visible after the add unique. */
7591bab1 MD	209	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
7591bab1	210	urcu_ref_init(&vstream->ref);
c51b2177	211	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
7591bab1	212
2f8f53af DG	213	return vstream;
	214
	215	error:
	216	if (vstream) {
0f31e182 MD	217	/* Not using `put` since vstream is assumed to be published. */
0f31e182 MD	218	viewer_stream_release_composite_objects(vstream);
7591bab1	219	viewer_stream_destroy(vstream);
2f8f53af DG	220	}
	221	return NULL;
	222	}
	223
7591bab1	224	static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
2f8f53af DG	225	{
	226	int ret;
	227	struct lttng_ht_iter iter;
	228
7591bab1	229	iter.iter.node = &vstream->stream_n.node;
2f8f53af DG	230	ret = lttng_ht_del(viewer_streams_ht, &iter);
	231	assert(!ret);
	232	}
	233
7591bab1	234	static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af	235	{
7591bab1 MD	236	struct relay_viewer_stream *vstream = caa_container_of(ref,
7591bab1 MD	237	struct relay_viewer_stream, ref);
2a174661	238
7591bab1 MD	239	if (vstream->stream->is_metadata) {
7591bab1 MD	240	rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661	241	}
7591bab1	242	viewer_stream_unpublish(vstream);
0f31e182	243	viewer_stream_release_composite_objects(vstream);
7591bab1 MD	244	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
	245	}
	246
	247	/* Must be called with RCU read-side lock held. */
	248	bool viewer_stream_get(struct relay_viewer_stream *vstream)
	249	{
ce4d4083	250	return urcu_ref_get_unless_zero(&vstream->ref);
2f8f53af DG	251	}
	252
	253	/*
7591bab1	254	* Get viewer stream by id.
2f8f53af	255	*
7591bab1	256	* Return viewer stream if found else NULL.
2f8f53af	257	*/
7591bab1	258	struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
2f8f53af DG	259	{
	260	struct lttng_ht_node_u64 *node;
	261	struct lttng_ht_iter iter;
7591bab1	262	struct relay_viewer_stream *vstream = NULL;
2f8f53af	263
7591bab1	264	rcu_read_lock();
2f8f53af DG	265	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	266	node = lttng_ht_iter_get_node_u64(&iter);
	267	if (!node) {
	268	DBG("Relay viewer stream %" PRIu64 " not found", id);
	269	goto end;
	270	}
7591bab1 MD	271	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	272	if (!viewer_stream_get(vstream)) {
	273	vstream = NULL;
	274	}
2f8f53af	275	end:
7591bab1 MD	276	rcu_read_unlock();
	277	return vstream;
	278	}
	279
	280	void viewer_stream_put(struct relay_viewer_stream *vstream)
	281	{
	282	rcu_read_lock();
7591bab1	283	urcu_ref_put(&vstream->ref, viewer_stream_release);
7591bab1 MD	284	rcu_read_unlock();
	285	}
	286
3087b021 MD	287	void viewer_stream_close_files(struct relay_viewer_stream *vstream)
	288	{
	289	if (vstream->index_file) {
	290	lttng_index_file_put(vstream->index_file);
	291	vstream->index_file = NULL;
	292	}
8bb66c3c JG	293	if (vstream->stream_file.handle) {
	294	fs_handle_close(vstream->stream_file.handle);
	295	vstream->stream_file.handle = NULL;
3087b021 MD	296	}
	297	}
	298
	299	void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
	300	{
	301	const struct relay_stream *stream = vstream->stream;
	302	uint64_t seq_tail;
	303
	304	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
	305	seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	306	if (seq_tail == -1ULL) {
	307	seq_tail = 0;
	308	}
90faeb9e MD	309
	310	/*
	311	* Move the index sent seqcount forward if it was lagging behind
	312	* the new tail of the tracefile array. If the current
	313	* index_sent_seqcount is already further than the tracefile
	314	* array tail position, keep its current position.
	315	*/
	316	vstream->index_sent_seqcount = seq_tail > vstream->index_sent_seqcount ?
	317	seq_tail : vstream->index_sent_seqcount;
3087b021 MD	318	}
3087b021 MD	319
2f8f53af DG	320	/*
	321	* Rotate a stream to the next tracefile.
	322	*
7591bab1	323	* Must be called with the rstream lock held.
b0d240a2	324	* Returns 0 on success, 1 on EOF.
2f8f53af	325	*/
7591bab1	326	int viewer_stream_rotate(struct relay_viewer_stream *vstream)
2f8f53af DG	327	{
2f8f53af DG	328	int ret;
a44ca2ca	329	uint64_t new_id;
ebb29c10	330	const struct relay_stream *stream = vstream->stream;
2f8f53af	331
7591bab1	332	/* Detect the last tracefile to open. */
a44ca2ca MD	333	if (stream->index_received_seqcount
a44ca2ca MD	334	== vstream->index_sent_seqcount
7591bab1 MD	335	&& stream->trace->session->connection_closed) {
7591bab1 MD	336	ret = 1;
2a174661 DG	337	goto end;
2a174661 DG	338	}
2f8f53af	339
7591bab1 MD	340	if (stream->tracefile_count == 0) {
	341	/* Ignore rotation, there is none to do. */
	342	ret = 0;
2f8f53af DG	343	goto end;
	344	}
	345
a44ca2ca MD	346	/*
	347	* Try to move to the next file.
	348	*/
	349	new_id = (vstream->current_tracefile_id + 1)
	350	% stream->tracefile_count;
	351	if (tracefile_array_seq_in_file(stream->tfa, new_id,
	352	vstream->index_sent_seqcount)) {
	353	vstream->current_tracefile_id = new_id;
2f8f53af	354	} else {
a44ca2ca MD	355	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	356
	357	/*
	358	* This can only be reached on overwrite, which implies there
	359	* has been data written at some point, which will have set the
	360	* tail.
	361	*/
	362	assert(seq_tail != -1ULL);
	363	/*
	364	* We need to resync because we lag behind tail.
	365	*/
7591bab1	366	vstream->current_tracefile_id =
a44ca2ca MD	367	tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca MD	368	vstream->index_sent_seqcount = seq_tail;
2f8f53af	369	}
b0d240a2 MD	370	viewer_stream_close_files(vstream);
b0d240a2 MD	371	ret = 0;
2f8f53af	372	end:
2f8f53af DG	373	return ret;
2f8f53af DG	374	}
7591bab1 MD	375
	376	void print_viewer_streams(void)
	377	{
	378	struct lttng_ht_iter iter;
	379	struct relay_viewer_stream *vstream;
	380
ce3f3ba3 JG	381	if (!viewer_streams_ht) {
	382	return;
	383	}
	384
7591bab1 MD	385	rcu_read_lock();
	386	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
	387	stream_n.node) {
	388	if (!viewer_stream_get(vstream)) {
	389	continue;
	390	}
	391	DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
	392	" session %" PRIu64,
	393	vstream,
	394	vstream->ref.refcount,
	395	vstream->stream->stream_handle,
	396	vstream->stream->trace->id,
	397	vstream->stream->trace->session->id);
	398	viewer_stream_put(vstream);
	399	}
	400	rcu_read_unlock();
	401	}