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

/*
 * 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 "lttng-relayd.hpp"
#include "viewer-stream.hpp"

#include <common/common.hpp>
#include <common/compat/string.hpp>
#include <common/index/index.hpp>
#include <common/urcu.hpp>
#include <common/utils.hpp>

#include <algorithm>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.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 = nullptr;
	}
	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = nullptr;
	}
	if (vstream->stream) {
		stream_put(vstream->stream);
		vstream->stream = nullptr;
	}
	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
	vstream->stream_file.trace_chunk = nullptr;
}

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 =
		lttng::utils::container_of(head, &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 = nullptr;

	ASSERT_LOCKED(stream->lock);

	vstream = zmalloc<relay_viewer_stream>();
	if (!vstream) {
		PERROR("relay viewer stream zmalloc");
		goto error;
	}

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

		LTTNG_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 == nullptr) {
		PERROR("relay viewer path_name alloc");
		goto error;
	}
	vstream->channel_name = lttng_strndup(stream->channel_name, LTTNG_VIEWER_NAME_MAX);
	if (vstream->channel_name == nullptr) {
		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 == nullptr) {
		vstream->index_file = nullptr;
	} else if (vstream->stream_file.trace_chunk) {
		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 = nullptr;
			} 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 && vstream->stream_file.trace_chunk) {
		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,
					     nullptr,
					     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 nullptr;
}

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);
	LTTNG_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 = nullptr;

	lttng::urcu::read_lock_guard 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 = lttng::utils::container_of(node, &relay_viewer_stream::stream_n);
	if (!viewer_stream_get(vstream)) {
		vstream = nullptr;
	}
end:
	return vstream;
}

void viewer_stream_put(struct relay_viewer_stream *vstream)
{
	lttng::urcu::read_lock_guard read_lock;
	urcu_ref_put(&vstream->ref, viewer_stream_release);
}

void viewer_stream_close_files(struct relay_viewer_stream *vstream)
{
	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = nullptr;
	}
	if (vstream->stream_file.handle) {
		fs_handle_close(vstream->stream_file.handle);
		vstream->stream_file.handle = nullptr;
	}
}

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 = std::max(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.
		 */
		LTTNG_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()
{
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream;

	if (!viewer_streams_ht) {
		return;
	}

	{
		lttng::urcu::read_lock_guard 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);
		}
	}
}
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
28ab034a JG	11	#include "lttng-relayd.hpp"
	12	#include "viewer-stream.hpp"
	13
c9e313bc	14	#include <common/common.hpp>
c9e313bc	15	#include <common/compat/string.hpp>
28ab034a	16	#include <common/index/index.hpp>
56047f5a	17	#include <common/urcu.hpp>
c9e313bc	18	#include <common/utils.hpp>
2f8f53af	19
28ab034a JG	20	#include <algorithm>
	21	#include <fcntl.h>
	22	#include <sys/stat.h>
	23	#include <sys/types.h>
2f8f53af	24
b9973dea	25	static void viewer_stream_release_composite_objects(struct relay_viewer_stream *vstream)
2f8f53af	26	{
b9973dea MD	27	if (vstream->stream_file.handle) {
b9973dea MD	28	fs_handle_close(vstream->stream_file.handle);
cd9adb8b	29	vstream->stream_file.handle = nullptr;
b9973dea MD	30	}
	31	if (vstream->index_file) {
	32	lttng_index_file_put(vstream->index_file);
cd9adb8b	33	vstream->index_file = nullptr;
b9973dea MD	34	}
	35	if (vstream->stream) {
	36	stream_put(vstream->stream);
cd9adb8b	37	vstream->stream = nullptr;
b9973dea	38	}
80516611	39	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
cd9adb8b	40	vstream->stream_file.trace_chunk = nullptr;
b9973dea MD	41	}
	42
	43	static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
	44	{
7591bab1 MD	45	free(vstream->path_name);
	46	free(vstream->channel_name);
	47	free(vstream);
2f8f53af DG	48	}
2f8f53af DG	49
7591bab1	50	static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af	51	{
7591bab1	52	struct relay_viewer_stream *vstream =
0114db0e	53	lttng::utils::container_of(head, &relay_viewer_stream::rcu_node);
2f8f53af	54
7591bab1	55	viewer_stream_destroy(vstream);
2f8f53af DG	56	}
2f8f53af DG	57
9edaf114	58	/* Relay stream's lock must be held by the caller. */
2f8f53af	59	struct relay_viewer_stream viewer_stream_create(struct relay_stream stream,
28ab034a JG	60	struct lttng_trace_chunk *trace_chunk,
28ab034a JG	61	enum lttng_viewer_seek seek_t)
2f8f53af	62	{
cd9adb8b	63	struct relay_viewer_stream *vstream = nullptr;
ebb29c10	64
9edaf114	65	ASSERT_LOCKED(stream->lock);
2f8f53af	66
64803277	67	vstream = zmalloc<relay_viewer_stream>();
2f8f53af DG	68	if (!vstream) {
	69	PERROR("relay viewer stream zmalloc");
	70	goto error;
	71	}
	72
80516611	73	if (trace_chunk) {
28ab034a	74	const bool acquired_reference = lttng_trace_chunk_get(trace_chunk);
80516611	75
a0377dfe	76	LTTNG_ASSERT(acquired_reference);
80516611 JG	77	}
80516611 JG	78
9edaf114	79	vstream->stream_file.trace_chunk = trace_chunk;
f5436bfc	80	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
cd9adb8b	81	if (vstream->path_name == nullptr) {
b272577e MD	82	PERROR("relay viewer path_name alloc");
	83	goto error;
	84	}
28ab034a	85	vstream->channel_name = lttng_strndup(stream->channel_name, LTTNG_VIEWER_NAME_MAX);
cd9adb8b	86	if (vstream->channel_name == nullptr) {
b272577e MD	87	PERROR("relay viewer channel_name alloc");
	88	goto error;
	89	}
2f8f53af	90
a44ca2ca MD	91	if (!stream_get(stream)) {
	92	ERR("Cannot get stream");
	93	goto error;
	94	}
	95	vstream->stream = stream;
	96
a44ca2ca MD	97	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
a44ca2ca MD	98	ERR("Cannot attach viewer metadata stream to trace (busy).");
71381736	99	goto error;
a44ca2ca MD	100	}
a44ca2ca MD	101
2f8f53af	102	switch (seek_t) {
c4e361a4	103	case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca MD	104	{
	105	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	106
	107	if (seq_tail == -1ULL) {
	108	/*
	109	* Tail may not be initialized yet. Nonetheless, we know
	110	* we want to send the first index once it becomes
	111	* available.
	112	*/
	113	seq_tail = 0;
	114	}
28ab034a	115	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca	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	*/
28ab034a	129	vstream->index_sent_seqcount = tracefile_array_get_seq_head(stream->tfa) + 1;
2f8f53af DG	130	break;
2f8f53af DG	131	default:
71381736	132	goto error;
2f8f53af	133	}
2f8f53af	134
2f8f53af	135	/*
a44ca2ca MD	136	* If we never received an index for the current stream, delay
a44ca2ca MD	137	* the opening of the index, otherwise open it right now.
2f8f53af	138	*/
cd9adb8b JG	139	if (stream->index_file == nullptr) {
cd9adb8b JG	140	vstream->index_file = nullptr;
0eafad74	141	} else if (vstream->stream_file.trace_chunk) {
ebb29c10 JG	142	const uint32_t connection_major = stream->trace->session->major;
ebb29c10 JG	143	const uint32_t connection_minor = stream->trace->session->minor;
3ff5c5db	144	enum lttng_trace_chunk_status chunk_status;
ebb29c10	145
3ff5c5db	146	chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
28ab034a JG	147	vstream->stream_file.trace_chunk,
	148	stream->path_name,
	149	stream->channel_name,
	150	stream->tracefile_size,
	151	vstream->current_tracefile_id,
	152	lttng_to_index_major(connection_major, connection_minor),
	153	lttng_to_index_minor(connection_major, connection_minor),
	154	true,
	155	&vstream->index_file);
3ff5c5db MD	156	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
3ff5c5db MD	157	if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
cd9adb8b	158	vstream->index_file = nullptr;
3ff5c5db	159	} else {
71381736	160	goto error;
3ff5c5db	161	}
2f8f53af	162	}
2f8f53af DG	163	}
2f8f53af DG	164
b0d240a2 MD	165	/*
	166	* If we never received a data file for the current stream, delay the
	167	* opening, otherwise open it right now.
	168	*/
0eafad74	169	if (stream->file && vstream->stream_file.trace_chunk) {
8bb66c3c	170	int ret;
b0d240a2 MD	171	char file_path[LTTNG_PATH_MAX];
	172	enum lttng_trace_chunk_status status;
	173
	174	ret = utils_stream_file_path(stream->path_name,
28ab034a JG	175	stream->channel_name,
	176	stream->tracefile_size,
	177	vstream->current_tracefile_id,
cd9adb8b	178	nullptr,
28ab034a JG	179	file_path,
28ab034a JG	180	sizeof(file_path));
b0d240a2	181	if (ret < 0) {
71381736	182	goto error;
b0d240a2 MD	183	}
b0d240a2 MD	184
28ab034a JG	185	status = lttng_trace_chunk_open_fs_handle(vstream->stream_file.trace_chunk,
	186	file_path,
	187	O_RDONLY,
	188	0,
	189	&vstream->stream_file.handle,
	190	true);
b0d240a2	191	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
71381736	192	goto error;
b0d240a2	193	}
b0d240a2 MD	194	}
b0d240a2 MD	195
f8f3885c	196	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
2f8f53af DG	197	off_t lseek_ret;
2f8f53af DG	198
28ab034a	199	lseek_ret = fs_handle_seek(vstream->index_file->file, 0, SEEK_END);
2f8f53af	200	if (lseek_ret < 0) {
71381736	201	goto error;
2f8f53af	202	}
7591bab1	203	}
7591bab1	204	if (stream->is_metadata) {
28ab034a	205	rcu_assign_pointer(stream->trace->viewer_metadata_stream, vstream);
2f8f53af DG	206	}
2f8f53af DG	207
80516611 JG	208	vstream->last_seen_rotation_count = stream->completed_rotation_count;
80516611 JG	209
7591bab1 MD	210	/* Globally visible after the add unique. */
7591bab1 MD	211	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
7591bab1	212	urcu_ref_init(&vstream->ref);
c51b2177	213	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
7591bab1	214
2f8f53af DG	215	return vstream;
	216
	217	error:
	218	if (vstream) {
b9973dea MD	219	/* Not using `put` since vstream is assumed to be published. */
b9973dea MD	220	viewer_stream_release_composite_objects(vstream);
7591bab1	221	viewer_stream_destroy(vstream);
2f8f53af	222	}
cd9adb8b	223	return nullptr;
2f8f53af DG	224	}
2f8f53af DG	225
7591bab1	226	static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
2f8f53af DG	227	{
	228	int ret;
	229	struct lttng_ht_iter iter;
	230
7591bab1	231	iter.iter.node = &vstream->stream_n.node;
2f8f53af	232	ret = lttng_ht_del(viewer_streams_ht, &iter);
a0377dfe	233	LTTNG_ASSERT(!ret);
2f8f53af DG	234	}
2f8f53af DG	235
7591bab1	236	static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af	237	{
28ab034a JG	238	struct relay_viewer_stream *vstream =
28ab034a JG	239	caa_container_of(ref, struct relay_viewer_stream, ref);
2a174661	240
7591bab1 MD	241	if (vstream->stream->is_metadata) {
7591bab1 MD	242	rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661	243	}
7591bab1	244	viewer_stream_unpublish(vstream);
b9973dea	245	viewer_stream_release_composite_objects(vstream);
7591bab1 MD	246	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
	247	}
	248
	249	/* Must be called with RCU read-side lock held. */
	250	bool viewer_stream_get(struct relay_viewer_stream *vstream)
	251	{
ce4d4083	252	return urcu_ref_get_unless_zero(&vstream->ref);
2f8f53af DG	253	}
	254
	255	/*
7591bab1	256	* Get viewer stream by id.
2f8f53af	257	*
7591bab1	258	* Return viewer stream if found else NULL.
2f8f53af	259	*/
7591bab1	260	struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
2f8f53af DG	261	{
	262	struct lttng_ht_node_u64 *node;
	263	struct lttng_ht_iter iter;
cd9adb8b	264	struct relay_viewer_stream *vstream = nullptr;
2f8f53af	265
56047f5a	266	lttng::urcu::read_lock_guard read_lock;
2f8f53af DG	267	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	268	node = lttng_ht_iter_get_node_u64(&iter);
	269	if (!node) {
	270	DBG("Relay viewer stream %" PRIu64 " not found", id);
	271	goto end;
	272	}
0114db0e	273	vstream = lttng::utils::container_of(node, &relay_viewer_stream::stream_n);
7591bab1	274	if (!viewer_stream_get(vstream)) {
cd9adb8b	275	vstream = nullptr;
7591bab1	276	}
2f8f53af	277	end:
7591bab1 MD	278	return vstream;
	279	}
	280
	281	void viewer_stream_put(struct relay_viewer_stream *vstream)
	282	{
56047f5a	283	lttng::urcu::read_lock_guard read_lock;
7591bab1	284	urcu_ref_put(&vstream->ref, viewer_stream_release);
7591bab1 MD	285	}
7591bab1 MD	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);
cd9adb8b	291	vstream->index_file = nullptr;
3087b021	292	}
8bb66c3c	293	if (vstream->stream_file.handle) {
28ab034a	294	fs_handle_close(vstream->stream_file.handle);
cd9adb8b	295	vstream->stream_file.handle = nullptr;
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	}
7fb6d478 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	*/
28ab034a	316	vstream->index_sent_seqcount = std::max(seq_tail, vstream->index_sent_seqcount);
3087b021 MD	317	}
3087b021 MD	318
2f8f53af DG	319	/*
	320	* Rotate a stream to the next tracefile.
	321	*
7591bab1	322	* Must be called with the rstream lock held.
b0d240a2	323	* Returns 0 on success, 1 on EOF.
2f8f53af	324	*/
7591bab1	325	int viewer_stream_rotate(struct relay_viewer_stream *vstream)
2f8f53af DG	326	{
2f8f53af DG	327	int ret;
a44ca2ca	328	uint64_t new_id;
ebb29c10	329	const struct relay_stream *stream = vstream->stream;
2f8f53af	330
7591bab1	331	/* Detect the last tracefile to open. */
28ab034a JG	332	if (stream->index_received_seqcount == vstream->index_sent_seqcount &&
28ab034a JG	333	stream->trace->session->connection_closed) {
7591bab1	334	ret = 1;
2a174661 DG	335	goto end;
2a174661 DG	336	}
2f8f53af	337
7591bab1 MD	338	if (stream->tracefile_count == 0) {
	339	/* Ignore rotation, there is none to do. */
	340	ret = 0;
2f8f53af DG	341	goto end;
	342	}
	343
a44ca2ca MD	344	/*
	345	* Try to move to the next file.
	346	*/
28ab034a JG	347	new_id = (vstream->current_tracefile_id + 1) % stream->tracefile_count;
28ab034a JG	348	if (tracefile_array_seq_in_file(stream->tfa, new_id, vstream->index_sent_seqcount)) {
a44ca2ca	349	vstream->current_tracefile_id = new_id;
2f8f53af	350	} else {
a44ca2ca MD	351	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	352
	353	/*
	354	* This can only be reached on overwrite, which implies there
	355	* has been data written at some point, which will have set the
	356	* tail.
	357	*/
a0377dfe	358	LTTNG_ASSERT(seq_tail != -1ULL);
a44ca2ca MD	359	/*
	360	* We need to resync because we lag behind tail.
	361	*/
28ab034a	362	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca	363	vstream->index_sent_seqcount = seq_tail;
2f8f53af	364	}
b0d240a2 MD	365	viewer_stream_close_files(vstream);
b0d240a2 MD	366	ret = 0;
2f8f53af	367	end:
2f8f53af DG	368	return ret;
2f8f53af DG	369	}
7591bab1	370
cd9adb8b	371	void print_viewer_streams()
7591bab1 MD	372	{
	373	struct lttng_ht_iter iter;
	374	struct relay_viewer_stream *vstream;
	375
ce3f3ba3 JG	376	if (!viewer_streams_ht) {
	377	return;
	378	}
	379
56047f5a JG	380	{
	381	lttng::urcu::read_lock_guard read_lock;
	382
	383	cds_lfht_for_each_entry (
	384	viewer_streams_ht->ht, &iter.iter, vstream, stream_n.node) {
	385	if (!viewer_stream_get(vstream)) {
	386	continue;
	387	}
	388	DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
	389	" session %" PRIu64,
	390	vstream,
	391	vstream->ref.refcount,
	392	vstream->stream->stream_handle,
	393	vstream->stream->trace->id,
	394	vstream->stream->trace->session->id);
	395	viewer_stream_put(vstream);
7591bab1	396	}
7591bab1	397	}
7591bab1	398	}