[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 <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 <algorithm>

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

static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
{
	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
	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 = (relay_viewer_stream *) 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);

		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 == 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 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 = 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 && 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, 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) {
		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);
	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);

	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;
	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 =
			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(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>
7fb6d478	18	#include <algorithm>
2f8f53af DG	19
	20	#include "lttng-relayd.h"
	21	#include "viewer-stream.h"
	22
7591bab1	23	static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
2f8f53af	24	{
80516611	25	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
7591bab1 MD	26	free(vstream->path_name);
	27	free(vstream->channel_name);
	28	free(vstream);
2f8f53af DG	29	}
2f8f53af DG	30
7591bab1	31	static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af	32	{
7591bab1	33	struct relay_viewer_stream *vstream =
2f8f53af DG	34	caa_container_of(head, struct relay_viewer_stream, rcu_node);
2f8f53af DG	35
7591bab1	36	viewer_stream_destroy(vstream);
2f8f53af DG	37	}
2f8f53af DG	38
9edaf114	39	/* Relay stream's lock must be held by the caller. */
2f8f53af	40	struct relay_viewer_stream viewer_stream_create(struct relay_stream stream,
9edaf114	41	struct lttng_trace_chunk *trace_chunk,
7591bab1	42	enum lttng_viewer_seek seek_t)
2f8f53af	43	{
ebb29c10	44	struct relay_viewer_stream *vstream = NULL;
ebb29c10	45
9edaf114	46	ASSERT_LOCKED(stream->lock);
2f8f53af	47
ac497a37	48	vstream = (relay_viewer_stream ) zmalloc(sizeof(vstream));
2f8f53af DG	49	if (!vstream) {
	50	PERROR("relay viewer stream zmalloc");
	51	goto error;
	52	}
	53
80516611 JG	54	if (trace_chunk) {
	55	const bool acquired_reference = lttng_trace_chunk_get(
	56	trace_chunk);
	57
a0377dfe	58	LTTNG_ASSERT(acquired_reference);
80516611 JG	59	}
80516611 JG	60
9edaf114	61	vstream->stream_file.trace_chunk = trace_chunk;
f5436bfc	62	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
b272577e MD	63	if (vstream->path_name == NULL) {
	64	PERROR("relay viewer path_name alloc");
	65	goto error;
	66	}
f5436bfc	67	vstream->channel_name = lttng_strndup(stream->channel_name,
2f8f53af	68	LTTNG_VIEWER_NAME_MAX);
b272577e MD	69	if (vstream->channel_name == NULL) {
	70	PERROR("relay viewer channel_name alloc");
	71	goto error;
	72	}
2f8f53af	73
a44ca2ca MD	74	if (!stream_get(stream)) {
	75	ERR("Cannot get stream");
	76	goto error;
	77	}
	78	vstream->stream = stream;
	79
a44ca2ca MD	80	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
a44ca2ca MD	81	ERR("Cannot attach viewer metadata stream to trace (busy).");
71381736	82	goto error;
a44ca2ca MD	83	}
a44ca2ca MD	84
2f8f53af	85	switch (seek_t) {
c4e361a4	86	case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca MD	87	{
	88	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	89
	90	if (seq_tail == -1ULL) {
	91	/*
	92	* Tail may not be initialized yet. Nonetheless, we know
	93	* we want to send the first index once it becomes
	94	* available.
	95	*/
	96	seq_tail = 0;
	97	}
	98	vstream->current_tracefile_id =
	99	tracefile_array_get_file_index_tail(stream->tfa);
	100	vstream->index_sent_seqcount = seq_tail;
2f8f53af	101	break;
a44ca2ca	102	}
c4e361a4	103	case LTTNG_VIEWER_SEEK_LAST:
a44ca2ca	104	vstream->current_tracefile_id =
78118e3b	105	tracefile_array_get_read_file_index_head(stream->tfa);
a44ca2ca MD	106	/*
	107	* We seek at the very end of each stream, awaiting for
	108	* a future packet to eventually come in.
	109	*
	110	* We don't need to check the head position for -1ULL since the
	111	* increment will set it to 0.
	112	*/
	113	vstream->index_sent_seqcount =
	114	tracefile_array_get_seq_head(stream->tfa) + 1;
2f8f53af DG	115	break;
2f8f53af DG	116	default:
71381736	117	goto error;
2f8f53af	118	}
2f8f53af	119
2f8f53af	120	/*
a44ca2ca MD	121	* If we never received an index for the current stream, delay
a44ca2ca MD	122	* the opening of the index, otherwise open it right now.
2f8f53af	123	*/
b0d240a2	124	if (stream->index_file == NULL) {
f8f3885c	125	vstream->index_file = NULL;
0eafad74	126	} else if (vstream->stream_file.trace_chunk) {
ebb29c10 JG	127	const uint32_t connection_major = stream->trace->session->major;
ebb29c10 JG	128	const uint32_t connection_minor = stream->trace->session->minor;
3ff5c5db	129	enum lttng_trace_chunk_status chunk_status;
ebb29c10	130
3ff5c5db	131	chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
b66a15d1 JG	132	vstream->stream_file.trace_chunk,
b66a15d1 JG	133	stream->path_name,
ebb29c10 JG	134	stream->channel_name, stream->tracefile_size,
	135	vstream->current_tracefile_id,
	136	lttng_to_index_major(connection_major,
	137	connection_minor),
	138	lttng_to_index_minor(connection_major,
3ff5c5db MD	139	connection_minor),
	140	true, &vstream->index_file);
	141	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
	142	if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
	143	vstream->index_file = NULL;
	144	} else {
71381736	145	goto error;
3ff5c5db	146	}
2f8f53af	147	}
2f8f53af DG	148	}
2f8f53af DG	149
b0d240a2 MD	150	/*
	151	* If we never received a data file for the current stream, delay the
	152	* opening, otherwise open it right now.
	153	*/
0eafad74	154	if (stream->file && vstream->stream_file.trace_chunk) {
8bb66c3c	155	int ret;
b0d240a2 MD	156	char file_path[LTTNG_PATH_MAX];
	157	enum lttng_trace_chunk_status status;
	158
	159	ret = utils_stream_file_path(stream->path_name,
	160	stream->channel_name, stream->tracefile_size,
	161	vstream->current_tracefile_id, NULL, file_path,
	162	sizeof(file_path));
	163	if (ret < 0) {
71381736	164	goto error;
b0d240a2 MD	165	}
b0d240a2 MD	166
8bb66c3c JG	167	status = lttng_trace_chunk_open_fs_handle(
	168	vstream->stream_file.trace_chunk, file_path,
	169	O_RDONLY, 0, &vstream->stream_file.handle,
	170	true);
b0d240a2	171	if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
71381736	172	goto error;
b0d240a2	173	}
b0d240a2 MD	174	}
b0d240a2 MD	175
f8f3885c	176	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
2f8f53af DG	177	off_t lseek_ret;
2f8f53af DG	178
8bb66c3c JG	179	lseek_ret = fs_handle_seek(
8bb66c3c JG	180	vstream->index_file->file, 0, SEEK_END);
2f8f53af	181	if (lseek_ret < 0) {
71381736	182	goto error;
2f8f53af	183	}
7591bab1	184	}
7591bab1 MD	185	if (stream->is_metadata) {
	186	rcu_assign_pointer(stream->trace->viewer_metadata_stream,
	187	vstream);
2f8f53af DG	188	}
2f8f53af DG	189
80516611 JG	190	vstream->last_seen_rotation_count = stream->completed_rotation_count;
80516611 JG	191
7591bab1 MD	192	/* Globally visible after the add unique. */
7591bab1 MD	193	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
7591bab1	194	urcu_ref_init(&vstream->ref);
c51b2177	195	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
7591bab1	196
2f8f53af DG	197	return vstream;
	198
	199	error:
	200	if (vstream) {
7591bab1	201	viewer_stream_destroy(vstream);
2f8f53af DG	202	}
	203	return NULL;
	204	}
	205
7591bab1	206	static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
2f8f53af DG	207	{
	208	int ret;
	209	struct lttng_ht_iter iter;
	210
7591bab1	211	iter.iter.node = &vstream->stream_n.node;
2f8f53af	212	ret = lttng_ht_del(viewer_streams_ht, &iter);
a0377dfe	213	LTTNG_ASSERT(!ret);
2f8f53af DG	214	}
2f8f53af DG	215
7591bab1	216	static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af	217	{
7591bab1 MD	218	struct relay_viewer_stream *vstream = caa_container_of(ref,
7591bab1 MD	219	struct relay_viewer_stream, ref);
2a174661	220
7591bab1 MD	221	if (vstream->stream->is_metadata) {
7591bab1 MD	222	rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661	223	}
2f8f53af	224
7591bab1 MD	225	viewer_stream_unpublish(vstream);
7591bab1 MD	226
8bb66c3c JG	227	if (vstream->stream_file.handle) {
	228	fs_handle_close(vstream->stream_file.handle);
	229	vstream->stream_file.handle = NULL;
2f8f53af	230	}
f8f3885c MD	231	if (vstream->index_file) {
	232	lttng_index_file_put(vstream->index_file);
	233	vstream->index_file = NULL;
7591bab1 MD	234	}
	235	if (vstream->stream) {
	236	stream_put(vstream->stream);
	237	vstream->stream = NULL;
	238	}
4c2717fc JG	239	lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
4c2717fc JG	240	vstream->stream_file.trace_chunk = NULL;
7591bab1 MD	241	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
	242	}
	243
	244	/* Must be called with RCU read-side lock held. */
	245	bool viewer_stream_get(struct relay_viewer_stream *vstream)
	246	{
ce4d4083	247	return urcu_ref_get_unless_zero(&vstream->ref);
2f8f53af DG	248	}
	249
	250	/*
7591bab1	251	* Get viewer stream by id.
2f8f53af	252	*
7591bab1	253	* Return viewer stream if found else NULL.
2f8f53af	254	*/
7591bab1	255	struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
2f8f53af DG	256	{
	257	struct lttng_ht_node_u64 *node;
	258	struct lttng_ht_iter iter;
7591bab1	259	struct relay_viewer_stream *vstream = NULL;
2f8f53af	260
7591bab1	261	rcu_read_lock();
2f8f53af DG	262	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	263	node = lttng_ht_iter_get_node_u64(&iter);
	264	if (!node) {
	265	DBG("Relay viewer stream %" PRIu64 " not found", id);
	266	goto end;
	267	}
7591bab1 MD	268	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	269	if (!viewer_stream_get(vstream)) {
	270	vstream = NULL;
	271	}
2f8f53af	272	end:
7591bab1 MD	273	rcu_read_unlock();
	274	return vstream;
	275	}
	276
	277	void viewer_stream_put(struct relay_viewer_stream *vstream)
	278	{
	279	rcu_read_lock();
7591bab1	280	urcu_ref_put(&vstream->ref, viewer_stream_release);
7591bab1 MD	281	rcu_read_unlock();
	282	}
	283
3087b021 MD	284	void viewer_stream_close_files(struct relay_viewer_stream *vstream)
	285	{
	286	if (vstream->index_file) {
	287	lttng_index_file_put(vstream->index_file);
	288	vstream->index_file = NULL;
	289	}
8bb66c3c JG	290	if (vstream->stream_file.handle) {
	291	fs_handle_close(vstream->stream_file.handle);
	292	vstream->stream_file.handle = NULL;
3087b021 MD	293	}
	294	}
	295
	296	void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
	297	{
	298	const struct relay_stream *stream = vstream->stream;
	299	uint64_t seq_tail;
	300
	301	vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
	302	seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	303	if (seq_tail == -1ULL) {
	304	seq_tail = 0;
	305	}
7fb6d478 MD	306
	307	/*
	308	* Move the index sent seqcount forward if it was lagging behind
	309	* the new tail of the tracefile array. If the current
	310	* index_sent_seqcount is already further than the tracefile
	311	* array tail position, keep its current position.
	312	*/
	313	vstream->index_sent_seqcount =
	314	std::max(seq_tail, vstream->index_sent_seqcount);
3087b021 MD	315	}
3087b021 MD	316
2f8f53af DG	317	/*
	318	* Rotate a stream to the next tracefile.
	319	*
7591bab1	320	* Must be called with the rstream lock held.
b0d240a2	321	* Returns 0 on success, 1 on EOF.
2f8f53af	322	*/
7591bab1	323	int viewer_stream_rotate(struct relay_viewer_stream *vstream)
2f8f53af DG	324	{
2f8f53af DG	325	int ret;
a44ca2ca	326	uint64_t new_id;
ebb29c10	327	const struct relay_stream *stream = vstream->stream;
2f8f53af	328
7591bab1	329	/* Detect the last tracefile to open. */
a44ca2ca MD	330	if (stream->index_received_seqcount
a44ca2ca MD	331	== vstream->index_sent_seqcount
7591bab1 MD	332	&& stream->trace->session->connection_closed) {
7591bab1 MD	333	ret = 1;
2a174661 DG	334	goto end;
2a174661 DG	335	}
2f8f53af	336
7591bab1 MD	337	if (stream->tracefile_count == 0) {
	338	/* Ignore rotation, there is none to do. */
	339	ret = 0;
2f8f53af DG	340	goto end;
	341	}
	342
a44ca2ca MD	343	/*
	344	* Try to move to the next file.
	345	*/
	346	new_id = (vstream->current_tracefile_id + 1)
	347	% stream->tracefile_count;
	348	if (tracefile_array_seq_in_file(stream->tfa, new_id,
	349	vstream->index_sent_seqcount)) {
	350	vstream->current_tracefile_id = new_id;
2f8f53af	351	} else {
a44ca2ca MD	352	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	353
	354	/*
	355	* This can only be reached on overwrite, which implies there
	356	* has been data written at some point, which will have set the
	357	* tail.
	358	*/
a0377dfe	359	LTTNG_ASSERT(seq_tail != -1ULL);
a44ca2ca MD	360	/*
	361	* We need to resync because we lag behind tail.
	362	*/
7591bab1	363	vstream->current_tracefile_id =
a44ca2ca MD	364	tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca MD	365	vstream->index_sent_seqcount = seq_tail;
2f8f53af	366	}
b0d240a2 MD	367	viewer_stream_close_files(vstream);
b0d240a2 MD	368	ret = 0;
2f8f53af	369	end:
2f8f53af DG	370	return ret;
2f8f53af DG	371	}
7591bab1 MD	372
	373	void print_viewer_streams(void)
	374	{
	375	struct lttng_ht_iter iter;
	376	struct relay_viewer_stream *vstream;
	377
ce3f3ba3 JG	378	if (!viewer_streams_ht) {
	379	return;
	380	}
	381
7591bab1 MD	382	rcu_read_lock();
	383	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
	384	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);
	396	}
	397	rcu_read_unlock();
	398	}