X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libust%2Fltt-events.c;fp=libust%2Fltt-events.c;h=0000000000000000000000000000000000000000;hb=69400ac4a4e6575f749c6326df7c2a2c8ac3bdc5;hp=68531bcd628e435e62805d52b5f593054ec5089b;hpb=f3049ad9e7b72287888452b9ed542c0f36e6eefe;p=ust.git

diff --git a/libust/ltt-events.c b/libust/ltt-events.c
deleted file mode 100644
index 68531bc..0000000
--- a/libust/ltt-events.c
+++ /dev/null
@@ -1,1010 +0,0 @@
-/*
- * ltt-events.c
- *
- * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Holds LTTng per-session event registry.
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#define _GNU_SOURCE
-#include <stdio.h>
-#include <endian.h>
-#include <urcu/list.h>
-#include <urcu/hlist.h>
-#include <pthread.h>
-#include <urcu-bp.h>
-#include <urcu/compiler.h>
-#include <urcu/uatomic.h>
-#include <uuid/uuid.h>
-#include <lttng/tracepoint.h>
-#include <errno.h>
-#include <sys/shm.h>
-#include <sys/ipc.h>
-#include <lttng/ust-events.h>
-#include <lttng/usterr-signal-safe.h>
-#include "lttng/core.h"
-#include "ltt-tracer.h"
-#include "ltt-tracer-core.h"
-#include "lttng/wait.h"
-#include "../libringbuffer/shm.h"
-
-typedef u32 uint32_t;
-#include <lttng/kcompat/jhash.h>
-
-/*
- * The sessions mutex is the centralized mutex across UST tracing
- * control and probe registration. All operations within this file are
- * called by the communication thread, under ust_lock protection.
- */
-static DEFINE_MUTEX(sessions_mutex);
-
-void ust_lock(void)
-{
-	pthread_mutex_lock(&sessions_mutex);
-}
-
-void ust_unlock(void)
-{
-	pthread_mutex_unlock(&sessions_mutex);
-}
-
-static CDS_LIST_HEAD(sessions);
-static CDS_LIST_HEAD(ltt_transport_list);
-
-/*
- * Pending probes hash table, containing the registered ltt events for
- * which tracepoint probes are still missing. Protected by the sessions
- * mutex.
- */
-#define PENDING_PROBE_HASH_BITS		6
-#define PENDING_PROBE_HASH_SIZE		(1 << PENDING_PROBE_HASH_BITS)
-static struct cds_hlist_head pending_probe_table[PENDING_PROBE_HASH_SIZE];
-
-struct ust_pending_probe {
-	struct ltt_event *event;
-	struct cds_hlist_node node;
-	char name[];
-};
-
-static void _ltt_event_destroy(struct ltt_event *event);
-static void _ltt_channel_destroy(struct ltt_channel *chan);
-static int _ltt_event_unregister(struct ltt_event *event);
-static
-int _ltt_event_metadata_statedump(struct ltt_session *session,
-				  struct ltt_channel *chan,
-				  struct ltt_event *event);
-static
-int _ltt_session_metadata_statedump(struct ltt_session *session);
-
-/*
- * called at event creation if probe is missing.
- * called with session mutex held.
- */
-static
-int add_pending_probe(struct ltt_event *event, const char *name)
-{
-	struct cds_hlist_head *head;
-	struct ust_pending_probe *e;
-	size_t name_len = strlen(name) + 1;
-	u32 hash = jhash(name, name_len - 1, 0);
-
-	head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
-	e = zmalloc(sizeof(struct ust_pending_probe) + name_len);
-	if (!e)
-		return -ENOMEM;
-	memcpy(&e->name[0], name, name_len);
-	cds_hlist_add_head(&e->node, head);
-	e->event = event;
-	event->pending_probe = e;
-	return 0;
-}
-
-/*
- * remove a pending probe. called when at event teardown and when an
- * event is fixed (probe is loaded).
- * called with session mutex held.
- */
-static
-void remove_pending_probe(struct ust_pending_probe *e)
-{
-	if (!e)
-		return;
-	cds_hlist_del(&e->node);
-	free(e);
-}
-
-/*
- * Called at library load: connect the probe on the events pending on
- * probe load.
- * called with session mutex held.
- */
-int pending_probe_fix_events(const struct lttng_event_desc *desc)
-{
-	struct cds_hlist_head *head;
-	struct cds_hlist_node *node, *p;
-	struct ust_pending_probe *e;
-	const char *name = desc->name;
-	size_t name_len = strlen(name) + 1;
-	u32 hash = jhash(name, name_len - 1, 0);
-	int ret = 0;
-
-	head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
-	cds_hlist_for_each_entry_safe(e, node, p, head, node) {
-		struct ltt_event *event;
-		struct ltt_channel *chan;
-
-		if (strcmp(name, e->name))
-			continue;
-		event = e->event;
-		chan = event->chan;
-		assert(!event->desc);
-		event->desc = desc;
-		event->pending_probe = NULL;
-		remove_pending_probe(e);
-		ret |= __tracepoint_probe_register(name,
-				event->desc->probe_callback,
-				event);
-		if (ret)
-			continue;
-		event->id = chan->free_event_id++;
-		ret |= _ltt_event_metadata_statedump(chan->session, chan,
-				event);
-	}
-	return ret;
-}
-
-void synchronize_trace(void)
-{
-	synchronize_rcu();
-}
-
-struct ltt_session *ltt_session_create(void)
-{
-	struct ltt_session *session;
-
-	session = zmalloc(sizeof(struct ltt_session));
-	if (!session)
-		return NULL;
-	CDS_INIT_LIST_HEAD(&session->chan);
-	CDS_INIT_LIST_HEAD(&session->events);
-	uuid_generate(session->uuid);
-	cds_list_add(&session->list, &sessions);
-	return session;
-}
-
-void ltt_session_destroy(struct ltt_session *session)
-{
-	struct ltt_channel *chan, *tmpchan;
-	struct ltt_event *event, *tmpevent;
-	int ret;
-
-	CMM_ACCESS_ONCE(session->active) = 0;
-	cds_list_for_each_entry(event, &session->events, list) {
-		ret = _ltt_event_unregister(event);
-		WARN_ON(ret);
-	}
-	synchronize_trace();	/* Wait for in-flight events to complete */
-	cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
-		_ltt_event_destroy(event);
-	cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
-		_ltt_channel_destroy(chan);
-	cds_list_del(&session->list);
-	free(session);
-}
-
-int ltt_session_enable(struct ltt_session *session)
-{
-	int ret = 0;
-	struct ltt_channel *chan;
-
-	if (session->active) {
-		ret = -EBUSY;
-		goto end;
-	}
-
-	/*
-	 * Snapshot the number of events per channel to know the type of header
-	 * we need to use.
-	 */
-	cds_list_for_each_entry(chan, &session->chan, list) {
-		if (chan->header_type)
-			continue;		/* don't change it if session stop/restart */
-		if (chan->free_event_id < 31)
-			chan->header_type = 1;	/* compact */
-		else
-			chan->header_type = 2;	/* large */
-	}
-
-	CMM_ACCESS_ONCE(session->active) = 1;
-	CMM_ACCESS_ONCE(session->been_active) = 1;
-	ret = _ltt_session_metadata_statedump(session);
-	if (ret)
-		CMM_ACCESS_ONCE(session->active) = 0;
-end:
-	return ret;
-}
-
-int ltt_session_disable(struct ltt_session *session)
-{
-	int ret = 0;
-
-	if (!session->active) {
-		ret = -EBUSY;
-		goto end;
-	}
-	CMM_ACCESS_ONCE(session->active) = 0;
-end:
-	return ret;
-}
-
-int ltt_channel_enable(struct ltt_channel *channel)
-{
-	int old;
-
-	if (channel == channel->session->metadata)
-		return -EPERM;
-	old = uatomic_xchg(&channel->enabled, 1);
-	if (old)
-		return -EEXIST;
-	return 0;
-}
-
-int ltt_channel_disable(struct ltt_channel *channel)
-{
-	int old;
-
-	if (channel == channel->session->metadata)
-		return -EPERM;
-	old = uatomic_xchg(&channel->enabled, 0);
-	if (!old)
-		return -EEXIST;
-	return 0;
-}
-
-int ltt_event_enable(struct ltt_event *event)
-{
-	int old;
-
-	if (event->chan == event->chan->session->metadata)
-		return -EPERM;
-	old = uatomic_xchg(&event->enabled, 1);
-	if (old)
-		return -EEXIST;
-	return 0;
-}
-
-int ltt_event_disable(struct ltt_event *event)
-{
-	int old;
-
-	if (event->chan == event->chan->session->metadata)
-		return -EPERM;
-	old = uatomic_xchg(&event->enabled, 0);
-	if (!old)
-		return -EEXIST;
-	return 0;
-}
-
-static struct ltt_transport *ltt_transport_find(const char *name)
-{
-	struct ltt_transport *transport;
-
-	cds_list_for_each_entry(transport, &ltt_transport_list, node) {
-		if (!strcmp(transport->name, name))
-			return transport;
-	}
-	return NULL;
-}
-
-struct ltt_channel *ltt_channel_create(struct ltt_session *session,
-				       const char *transport_name,
-				       void *buf_addr,
-				       size_t subbuf_size, size_t num_subbuf,
-				       unsigned int switch_timer_interval,
-				       unsigned int read_timer_interval,
-				       int *shm_fd, int *wait_fd,
-				       uint64_t *memory_map_size)
-{
-	struct ltt_channel *chan;
-	struct ltt_transport *transport;
-
-	if (session->been_active)
-		goto active;	/* Refuse to add channel to active session */
-	transport = ltt_transport_find(transport_name);
-	if (!transport) {
-		DBG("LTTng transport %s not found\n",
-		       transport_name);
-		goto notransport;
-	}
-	chan = zmalloc(sizeof(struct ltt_channel));
-	if (!chan)
-		goto nomem;
-	chan->session = session;
-	chan->id = session->free_chan_id++;
-	/*
-	 * Note: the channel creation op already writes into the packet
-	 * headers. Therefore the "chan" information used as input
-	 * should be already accessible.
-	 */
-	transport->ops.channel_create("[lttng]", chan, buf_addr,
-			subbuf_size, num_subbuf, switch_timer_interval,
-			read_timer_interval, shm_fd, wait_fd,
-			memory_map_size);
-	if (!chan->chan)
-		goto create_error;
-	chan->enabled = 1;
-	chan->ops = &transport->ops;
-	cds_list_add(&chan->list, &session->chan);
-	return chan;
-
-create_error:
-	free(chan);
-nomem:
-notransport:
-active:
-	return NULL;
-}
-
-/*
- * Only used internally at session destruction.
- */
-static
-void _ltt_channel_destroy(struct ltt_channel *chan)
-{
-	chan->ops->channel_destroy(chan);
-	cds_list_del(&chan->list);
-	lttng_destroy_context(chan->ctx);
-	free(chan);
-}
-
-/*
- * Supports event creation while tracing session is active.
- */
-struct ltt_event *ltt_event_create(struct ltt_channel *chan,
-				   struct lttng_ust_event *event_param,
-				   void *filter)
-{
-	struct ltt_event *event;
-	int ret;
-
-	if (chan->used_event_id == -1UL)
-		goto full;
-	/*
-	 * This is O(n^2) (for each event, the loop is called at event
-	 * creation). Might require a hash if we have lots of events.
-	 */
-	cds_list_for_each_entry(event, &chan->session->events, list)
-		if (event->desc && !strcmp(event->desc->name, event_param->name))
-			goto exist;
-	event = zmalloc(sizeof(struct ltt_event));
-	if (!event)
-		goto cache_error;
-	event->chan = chan;
-	event->filter = filter;
-	/*
-	 * used_event_id counts the maximum number of event IDs that can
-	 * register if all probes register.
-	 */
-	chan->used_event_id++;
-	event->enabled = 1;
-	event->instrumentation = event_param->instrumentation;
-	/* Populate ltt_event structure before tracepoint registration. */
-	cmm_smp_wmb();
-	switch (event_param->instrumentation) {
-	case LTTNG_UST_TRACEPOINT:
-		event->desc = ltt_event_get(event_param->name);
-		if (event->desc) {
-			ret = __tracepoint_probe_register(event_param->name,
-					event->desc->probe_callback,
-					event);
-			if (ret)
-				goto register_error;
-			event->id = chan->free_event_id++;
-		} else {
-			/*
-			 * If the probe is not present, event->desc stays NULL,
-			 * waiting for the probe to register, and the event->id
-			 * stays unallocated.
-			 */
-			ret = add_pending_probe(event, event_param->name);
-			if (ret)
-				goto add_pending_error;
-		}
-		break;
-	default:
-		WARN_ON_ONCE(1);
-	}
-	if (event->desc) {
-		ret = _ltt_event_metadata_statedump(chan->session, chan, event);
-		if (ret)
-			goto statedump_error;
-	}
-	cds_list_add(&event->list, &chan->session->events);
-	return event;
-
-statedump_error:
-	if (event->desc) {
-		WARN_ON_ONCE(__tracepoint_probe_unregister(event_param->name,
-					event->desc->probe_callback,
-					event));
-		ltt_event_put(event->desc);
-	}
-add_pending_error:
-register_error:
-	free(event);
-cache_error:
-exist:
-full:
-	return NULL;
-}
-
-/*
- * Only used internally at session destruction.
- */
-int _ltt_event_unregister(struct ltt_event *event)
-{
-	int ret = -EINVAL;
-
-	switch (event->instrumentation) {
-	case LTTNG_UST_TRACEPOINT:
-		if (event->desc) {
-			ret = __tracepoint_probe_unregister(event->desc->name,
-							  event->desc->probe_callback,
-							  event);
-			if (ret)
-				return ret;
-		} else {
-			remove_pending_probe(event->pending_probe);
-			ret = 0;
-		}
-		break;
-	default:
-		WARN_ON_ONCE(1);
-	}
-	return ret;
-}
-
-/*
- * Only used internally at session destruction.
- */
-static
-void _ltt_event_destroy(struct ltt_event *event)
-{
-	switch (event->instrumentation) {
-	case LTTNG_UST_TRACEPOINT:
-		if (event->desc) {
-			ltt_event_put(event->desc);
-		}
-		break;
-	default:
-		WARN_ON_ONCE(1);
-	}
-	cds_list_del(&event->list);
-	lttng_destroy_context(event->ctx);
-	free(event);
-}
-
-/*
- * We have exclusive access to our metadata buffer (protected by the
- * ust_lock), so we can do racy operations such as looking for
- * remaining space left in packet and write, since mutual exclusion
- * protects us from concurrent writes.
- */
-int lttng_metadata_printf(struct ltt_session *session,
-			  const char *fmt, ...)
-{
-	struct lttng_ust_lib_ring_buffer_ctx ctx;
-	struct ltt_channel *chan = session->metadata;
-	char *str = NULL;
-	int ret = 0, waitret;
-	size_t len, reserve_len, pos;
-	va_list ap;
-
-	WARN_ON_ONCE(!CMM_ACCESS_ONCE(session->active));
-
-	va_start(ap, fmt);
-	ret = vasprintf(&str, fmt, ap);
-	va_end(ap);
-	if (ret < 0)
-		return -ENOMEM;
-
-	len = strlen(str);
-	pos = 0;
-
-	for (pos = 0; pos < len; pos += reserve_len) {
-		reserve_len = min_t(size_t,
-				chan->ops->packet_avail_size(chan->chan, chan->handle),
-				len - pos);
-		lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
-					 sizeof(char), -1, chan->handle);
-		/*
-		 * We don't care about metadata buffer's records lost
-		 * count, because we always retry here. Report error if
-		 * we need to bail out after timeout or being
-		 * interrupted.
-		 */
-		waitret = wait_cond_interruptible_timeout(
-			({
-				ret = chan->ops->event_reserve(&ctx, 0);
-				ret != -ENOBUFS || !ret;
-			}),
-			LTTNG_METADATA_TIMEOUT_MSEC);
-		if (waitret == -ETIMEDOUT || waitret == -EINTR || ret) {
-			DBG("LTTng: Failure to write metadata to buffers (%s)\n",
-				waitret == -EINTR ? "interrupted" :
-					(ret == -ENOBUFS ? "timeout" : "I/O error"));
-			if (waitret == -EINTR)
-				ret = waitret;
-			goto end;
-		}
-		chan->ops->event_write(&ctx, &str[pos], reserve_len);
-		chan->ops->event_commit(&ctx);
-	}
-end:
-	free(str);
-	return ret;
-}
-
-static
-int _ltt_field_statedump(struct ltt_session *session,
-			 const struct lttng_event_field *field)
-{
-	int ret = 0;
-
-	switch (field->type.atype) {
-	case atype_integer:
-		ret = lttng_metadata_printf(session,
-			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
-			field->type.u.basic.integer.size,
-			field->type.u.basic.integer.alignment,
-			field->type.u.basic.integer.signedness,
-			(field->type.u.basic.integer.encoding == lttng_encode_none)
-				? "none"
-				: (field->type.u.basic.integer.encoding == lttng_encode_UTF8)
-					? "UTF8"
-					: "ASCII",
-			field->type.u.basic.integer.base,
-#if (BYTE_ORDER == BIG_ENDIAN)
-			field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
-#else
-			field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
-#endif
-			field->name);
-		break;
-	case atype_float:
-		ret = lttng_metadata_printf(session,
-			"		floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
-			field->type.u.basic._float.exp_dig,
-			field->type.u.basic._float.mant_dig,
-			field->type.u.basic._float.alignment,
-#if (BYTE_ORDER == BIG_ENDIAN)
-			field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
-#else
-			field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
-#endif
-			field->name);
-		break;
-	case atype_enum:
-		ret = lttng_metadata_printf(session,
-			"		%s %s;\n",
-			field->type.u.basic.enumeration.name,
-			field->name);
-		break;
-	case atype_array:
-	{
-		const struct lttng_basic_type *elem_type;
-
-		elem_type = &field->type.u.array.elem_type;
-		ret = lttng_metadata_printf(session,
-			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
-			elem_type->u.basic.integer.size,
-			elem_type->u.basic.integer.alignment,
-			elem_type->u.basic.integer.signedness,
-			(elem_type->u.basic.integer.encoding == lttng_encode_none)
-				? "none"
-				: (elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
-					? "UTF8"
-					: "ASCII",
-			elem_type->u.basic.integer.base,
-#if (BYTE_ORDER == BIG_ENDIAN)
-			elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
-#else
-			elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
-#endif
-			field->name, field->type.u.array.length);
-		break;
-	}
-	case atype_sequence:
-	{
-		const struct lttng_basic_type *elem_type;
-		const struct lttng_basic_type *length_type;
-
-		elem_type = &field->type.u.sequence.elem_type;
-		length_type = &field->type.u.sequence.length_type;
-		ret = lttng_metadata_printf(session,
-			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
-			length_type->u.basic.integer.size,
-			(unsigned int) length_type->u.basic.integer.alignment,
-			length_type->u.basic.integer.signedness,
-			(length_type->u.basic.integer.encoding == lttng_encode_none)
-				? "none"
-				: ((length_type->u.basic.integer.encoding == lttng_encode_UTF8)
-					? "UTF8"
-					: "ASCII"),
-			length_type->u.basic.integer.base,
-#if (BYTE_ORDER == BIG_ENDIAN)
-			length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
-#else
-			length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
-#endif
-			field->name);
-		if (ret)
-			return ret;
-
-		ret = lttng_metadata_printf(session,
-			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
-			elem_type->u.basic.integer.size,
-			(unsigned int) elem_type->u.basic.integer.alignment,
-			elem_type->u.basic.integer.signedness,
-			(elem_type->u.basic.integer.encoding == lttng_encode_none)
-				? "none"
-				: ((elem_type->u.basic.integer.encoding == lttng_encode_UTF8)
-					? "UTF8"
-					: "ASCII"),
-			elem_type->u.basic.integer.base,
-#if (BYTE_ORDER == BIG_ENDIAN)
-			elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
-#else
-			elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
-#endif
-			field->name,
-			field->name);
-		break;
-	}
-
-	case atype_string:
-		/* Default encoding is UTF8 */
-		ret = lttng_metadata_printf(session,
-			"		string%s _%s;\n",
-			field->type.u.basic.string.encoding == lttng_encode_ASCII ?
-				" { encoding = ASCII; }" : "",
-			field->name);
-		break;
-	default:
-		WARN_ON_ONCE(1);
-		return -EINVAL;
-	}
-	return ret;
-}
-
-static
-int _ltt_context_metadata_statedump(struct ltt_session *session,
-				    struct lttng_ctx *ctx)
-{
-	int ret = 0;
-	int i;
-
-	if (!ctx)
-		return 0;
-	for (i = 0; i < ctx->nr_fields; i++) {
-		const struct lttng_ctx_field *field = &ctx->fields[i];
-
-		ret = _ltt_field_statedump(session, &field->event_field);
-		if (ret)
-			return ret;
-	}
-	return ret;
-}
-
-static
-int _ltt_fields_metadata_statedump(struct ltt_session *session,
-				   struct ltt_event *event)
-{
-	const struct lttng_event_desc *desc = event->desc;
-	int ret = 0;
-	int i;
-
-	for (i = 0; i < desc->nr_fields; i++) {
-		const struct lttng_event_field *field = &desc->fields[i];
-
-		ret = _ltt_field_statedump(session, field);
-		if (ret)
-			return ret;
-	}
-	return ret;
-}
-
-static
-int _ltt_event_metadata_statedump(struct ltt_session *session,
-				  struct ltt_channel *chan,
-				  struct ltt_event *event)
-{
-	int ret = 0;
-
-	if (event->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
-		return 0;
-	if (chan == session->metadata)
-		return 0;
-	/*
-	 * Don't print events for which probe load is pending.
-	 */
-	if (!event->desc)
-		return 0;
-
-	ret = lttng_metadata_printf(session,
-		"event {\n"
-		"	name = %s;\n"
-		"	id = %u;\n"
-		"	stream_id = %u;\n",
-		event->desc->name,
-		event->id,
-		event->chan->id);
-	if (ret)
-		goto end;
-
-	if (event->ctx) {
-		ret = lttng_metadata_printf(session,
-			"	context := struct {\n");
-		if (ret)
-			goto end;
-	}
-	ret = _ltt_context_metadata_statedump(session, event->ctx);
-	if (ret)
-		goto end;
-	if (event->ctx) {
-		ret = lttng_metadata_printf(session,
-			"	};\n");
-		if (ret)
-			goto end;
-	}
-
-	ret = lttng_metadata_printf(session,
-		"	fields := struct {\n"
-		);
-	if (ret)
-		goto end;
-
-	ret = _ltt_fields_metadata_statedump(session, event);
-	if (ret)
-		goto end;
-
-	/*
-	 * LTTng space reservation can only reserve multiples of the
-	 * byte size.
-	 */
-	ret = lttng_metadata_printf(session,
-		"	};\n"
-		"};\n\n");
-	if (ret)
-		goto end;
-
-	event->metadata_dumped = 1;
-end:
-	return ret;
-
-}
-
-static
-int _ltt_channel_metadata_statedump(struct ltt_session *session,
-				    struct ltt_channel *chan)
-{
-	int ret = 0;
-
-	if (chan->metadata_dumped || !CMM_ACCESS_ONCE(session->active))
-		return 0;
-	if (chan == session->metadata)
-		return 0;
-
-	WARN_ON_ONCE(!chan->header_type);
-	ret = lttng_metadata_printf(session,
-		"stream {\n"
-		"	id = %u;\n"
-		"	event.header := %s;\n"
-		"	packet.context := struct packet_context;\n",
-		chan->id,
-		chan->header_type == 1 ? "struct event_header_compact" :
-			"struct event_header_large");
-	if (ret)
-		goto end;
-
-	if (chan->ctx) {
-		ret = lttng_metadata_printf(session,
-			"	event.context := struct {\n");
-		if (ret)
-			goto end;
-	}
-	ret = _ltt_context_metadata_statedump(session, chan->ctx);
-	if (ret)
-		goto end;
-	if (chan->ctx) {
-		ret = lttng_metadata_printf(session,
-			"	};\n");
-		if (ret)
-			goto end;
-	}
-
-	ret = lttng_metadata_printf(session,
-		"};\n\n");
-
-	chan->metadata_dumped = 1;
-end:
-	return ret;
-}
-
-static
-int _ltt_stream_packet_context_declare(struct ltt_session *session)
-{
-	return lttng_metadata_printf(session,
-		"struct packet_context {\n"
-		"	uint64_t timestamp_begin;\n"
-		"	uint64_t timestamp_end;\n"
-		"	uint32_t events_discarded;\n"
-		"	uint32_t content_size;\n"
-		"	uint32_t packet_size;\n"
-		"	uint32_t cpu_id;\n"
-		"};\n\n"
-		);
-}
-
-/*
- * Compact header:
- * id: range: 0 - 30.
- * id 31 is reserved to indicate an extended header.
- *
- * Large header:
- * id: range: 0 - 65534.
- * id 65535 is reserved to indicate an extended header.
- */
-static
-int _ltt_event_header_declare(struct ltt_session *session)
-{
-	return lttng_metadata_printf(session,
-	"struct event_header_compact {\n"
-	"	enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
-	"	variant <id> {\n"
-	"		struct {\n"
-	"			uint27_t timestamp;\n"
-	"		} compact;\n"
-	"		struct {\n"
-	"			uint32_t id;\n"
-	"			uint64_t timestamp;\n"
-	"		} extended;\n"
-	"	} v;\n"
-	"} align(%u);\n"
-	"\n"
-	"struct event_header_large {\n"
-	"	enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
-	"	variant <id> {\n"
-	"		struct {\n"
-	"			uint32_t timestamp;\n"
-	"		} compact;\n"
-	"		struct {\n"
-	"			uint32_t id;\n"
-	"			uint64_t timestamp;\n"
-	"		} extended;\n"
-	"	} v;\n"
-	"} align(%u);\n\n",
-	lttng_alignof(uint32_t) * CHAR_BIT,
-	lttng_alignof(uint16_t) * CHAR_BIT
-	);
-}
-
-/*
- * Output metadata into this session's metadata buffers.
- */
-static
-int _ltt_session_metadata_statedump(struct ltt_session *session)
-{
-	unsigned char *uuid_c = session->uuid;
-	char uuid_s[37];
-	struct ltt_channel *chan;
-	struct ltt_event *event;
-	int ret = 0;
-
-	if (!CMM_ACCESS_ONCE(session->active))
-		return 0;
-	if (session->metadata_dumped)
-		goto skip_session;
-	if (!session->metadata) {
-		DBG("LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
-		return -EPERM;
-	}
-
-	snprintf(uuid_s, sizeof(uuid_s),
-		"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
-		uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
-		uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
-		uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
-		uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
-
-	ret = lttng_metadata_printf(session,
-		"typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
-		"typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
-		"typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
-		"typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
-		"typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
-		"typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
-		"\n"
-		"trace {\n"
-		"	major = %u;\n"
-		"	minor = %u;\n"
-		"	uuid = \"%s\";\n"
-		"	byte_order = %s;\n"
-		"	packet.header := struct {\n"
-		"		uint32_t magic;\n"
-		"		uint8_t  uuid[16];\n"
-		"		uint32_t stream_id;\n"
-		"	};\n"
-		"};\n\n",
-		lttng_alignof(uint8_t) * CHAR_BIT,
-		lttng_alignof(uint16_t) * CHAR_BIT,
-		lttng_alignof(uint32_t) * CHAR_BIT,
-		lttng_alignof(uint64_t) * CHAR_BIT,
-		CTF_VERSION_MAJOR,
-		CTF_VERSION_MINOR,
-		uuid_s,
-#if (BYTE_ORDER == BIG_ENDIAN)
-		"be"
-#else
-		"le"
-#endif
-		);
-	if (ret)
-		goto end;
-
-	ret = _ltt_stream_packet_context_declare(session);
-	if (ret)
-		goto end;
-
-	ret = _ltt_event_header_declare(session);
-	if (ret)
-		goto end;
-
-skip_session:
-	cds_list_for_each_entry(chan, &session->chan, list) {
-		ret = _ltt_channel_metadata_statedump(session, chan);
-		if (ret)
-			goto end;
-	}
-
-	cds_list_for_each_entry(event, &session->events, list) {
-		ret = _ltt_event_metadata_statedump(session, event->chan, event);
-		if (ret)
-			goto end;
-	}
-	session->metadata_dumped = 1;
-end:
-	return ret;
-}
-
-/**
- * ltt_transport_register - LTT transport registration
- * @transport: transport structure
- *
- * Registers a transport which can be used as output to extract the data out of
- * LTTng. Called with ust_lock held.
- */
-void ltt_transport_register(struct ltt_transport *transport)
-{
-	cds_list_add_tail(&transport->node, &ltt_transport_list);
-}
-
-/**
- * ltt_transport_unregister - LTT transport unregistration
- * @transport: transport structure
- * Called with ust_lock held.
- */
-void ltt_transport_unregister(struct ltt_transport *transport)
-{
-	cds_list_del(&transport->node);
-}
-
-void lttng_ust_events_exit(void)
-{
-	struct ltt_session *session, *tmpsession;
-
-	cds_list_for_each_entry_safe(session, tmpsession, &sessions, list)
-		ltt_session_destroy(session);
-}