X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Ftrace-kernel.c;h=a453fd8b705537ba8908e729517c20b408ef2951;hp=8e074fd91b0dcbe829f8c053d32ac6e92766d32c;hb=7c1f6da21f4d46d9c834820a2b26f0634c7365a9;hpb=645328ae989e5f50a3a49c1ac34b2fee287a3d7b

diff --git a/src/bin/lttng-sessiond/trace-kernel.c b/src/bin/lttng-sessiond/trace-kernel.c
index 8e074fd91..a453fd8b7 100644
--- a/src/bin/lttng-sessiond/trace-kernel.c
+++ b/src/bin/lttng-sessiond/trace-kernel.c
@@ -1,37 +1,45 @@
 /*
- * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
+#include <lttng/event.h>
+#include <lttng/lttng-error.h>
+#include <lttng/kernel-probe.h>
+#include <lttng/userspace-probe.h>
+#include <lttng/userspace-probe-internal.h>
+#include <lttng/event-rule/event-rule.h>
+#include <lttng/event-rule/event-rule-internal.h>
+#include <lttng/event-rule/kernel-probe.h>
+#include <lttng/event-rule/kernel-probe-internal.h>
+#include <lttng/event-rule/syscall.h>
+#include <lttng/event-rule/syscall-internal.h>
+#include <lttng/event-rule/tracepoint.h>
+#include <lttng/event-rule/tracepoint-internal.h>
+#include <lttng/event-rule/userspace-probe-internal.h>
 #include <common/common.h>
 #include <common/defaults.h>
+#include <common/trace-chunk.h>
+#include <common/macros.h>
 
 #include "consumer.h"
 #include "trace-kernel.h"
+#include "lttng-sessiond.h"
+#include "notification-thread-commands.h"
 
 /*
  * Find the channel name for the given kernel session.
  */
 struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
-		char *name, struct ltt_kernel_session *session)
+		const char *name, struct ltt_kernel_session *session)
 {
 	struct ltt_kernel_channel *chan;
 
@@ -57,26 +65,79 @@ struct ltt_kernel_channel *trace_kernel_get_channel_by_name(
 	return NULL;
 }
 
+/*
+ * Find the event for the given channel.
+ */
+struct ltt_kernel_event *trace_kernel_find_event(
+		char *name, struct ltt_kernel_channel *channel,
+		enum lttng_event_type type,
+		struct lttng_bytecode *filter)
+{
+	struct ltt_kernel_event *ev;
+	int found = 0;
+
+	assert(name);
+	assert(channel);
+
+	cds_list_for_each_entry(ev, &channel->events_list.head, list) {
+		if (type != LTTNG_EVENT_ALL && ev->type != type) {
+			continue;
+		}
+		if (strcmp(name, ev->event->name)) {
+			continue;
+		}
+		if ((ev->filter && !filter) || (!ev->filter && filter)) {
+			continue;
+		}
+		if (ev->filter && filter) {
+			if (ev->filter->len != filter->len ||
+					memcmp(ev->filter->data, filter->data,
+						filter->len) != 0) {
+				continue;
+			}
+		}
+		found = 1;
+		break;
+	}
+	if (found) {
+		DBG("Found event %s for channel %s", name,
+			channel->channel->name);
+		return ev;
+	} else {
+		return NULL;
+	}
+}
+
 /*
  * Find the event name for the given channel.
  */
 struct ltt_kernel_event *trace_kernel_get_event_by_name(
-		char *name, struct ltt_kernel_channel *channel)
+		char *name, struct ltt_kernel_channel *channel,
+		enum lttng_event_type type)
 {
 	struct ltt_kernel_event *ev;
+	int found = 0;
 
 	assert(name);
 	assert(channel);
 
 	cds_list_for_each_entry(ev, &channel->events_list.head, list) {
-		if (strcmp(name, ev->event->name) == 0) {
-			DBG("Found event by name %s for channel %s", name,
-					channel->channel->name);
-			return ev;
+		if (type != LTTNG_EVENT_ALL && ev->type != type) {
+			continue;
+		}
+		if (strcmp(name, ev->event->name)) {
+			continue;
 		}
+		found = 1;
+		break;
+	}
+	if (found) {
+		DBG("Found event %s for channel %s", name,
+			channel->channel->name);
+		return ev;
+	} else {
+		return NULL;
 	}
-
-	return NULL;
 }
 
 /*
@@ -103,22 +164,44 @@ struct ltt_kernel_session *trace_kernel_create_session(void)
 	lks->metadata = NULL;
 	CDS_INIT_LIST_HEAD(&lks->channel_list.head);
 
+	lks->tracker_pid = process_attr_tracker_create();
+	if (!lks->tracker_pid) {
+		goto error;
+	}
+	lks->tracker_vpid = process_attr_tracker_create();
+	if (!lks->tracker_vpid) {
+		goto error;
+	}
+	lks->tracker_uid = process_attr_tracker_create();
+	if (!lks->tracker_uid) {
+		goto error;
+	}
+	lks->tracker_vuid = process_attr_tracker_create();
+	if (!lks->tracker_vuid) {
+		goto error;
+	}
+	lks->tracker_gid = process_attr_tracker_create();
+	if (!lks->tracker_gid) {
+		goto error;
+	}
+	lks->tracker_vgid = process_attr_tracker_create();
+	if (!lks->tracker_vgid) {
+		goto error;
+	}
 	lks->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 	if (lks->consumer == NULL) {
 		goto error;
 	}
 
-	/*
-	 * The tmp_consumer stays NULL until a set_consumer_uri command is
-	 * executed. At this point, the consumer should be nullify until an
-	 * enable_consumer command. This assignment is symbolic since we've zmalloc
-	 * the struct.
-	 */
-	lks->tmp_consumer = NULL;
-
 	return lks;
 
 error:
+	process_attr_tracker_destroy(lks->tracker_pid);
+	process_attr_tracker_destroy(lks->tracker_vpid);
+	process_attr_tracker_destroy(lks->tracker_uid);
+	process_attr_tracker_destroy(lks->tracker_vuid);
+	process_attr_tracker_destroy(lks->tracker_gid);
+	process_attr_tracker_destroy(lks->tracker_vgid);
 	free(lks);
 
 alloc_error:
@@ -134,6 +217,7 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
 		struct lttng_channel *chan)
 {
 	struct ltt_kernel_channel *lkc;
+	struct lttng_channel_extended *extended = NULL;
 
 	assert(chan);
 
@@ -146,10 +230,18 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
 	lkc->channel = zmalloc(sizeof(struct lttng_channel));
 	if (lkc->channel == NULL) {
 		PERROR("lttng_channel zmalloc");
-		free(lkc);
+		goto error;
+	}
+
+	extended = zmalloc(sizeof(struct lttng_channel_extended));
+	if (!extended) {
+		PERROR("lttng_channel_channel zmalloc");
 		goto error;
 	}
 	memcpy(lkc->channel, chan, sizeof(struct lttng_channel));
+	memcpy(extended, chan->attr.extended.ptr, sizeof(struct lttng_channel_extended));
+	lkc->channel->attr.extended.ptr = extended;
+	extended = NULL;
 
 	/*
 	 * If we receive an empty string for channel name, it means the
@@ -165,6 +257,7 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
 	lkc->stream_count = 0;
 	lkc->event_count = 0;
 	lkc->enabled = 1;
+	lkc->published_to_notification_thread = false;
 	/* Init linked list */
 	CDS_INIT_LIST_HEAD(&lkc->events_list.head);
 	CDS_INIT_LIST_HEAD(&lkc->stream_list.head);
@@ -173,6 +266,11 @@ struct ltt_kernel_channel *trace_kernel_create_channel(
 	return lkc;
 
 error:
+	if (lkc) {
+		free(lkc->channel);
+	}
+	free(extended);
+	free(lkc);
 	return NULL;
 }
 
@@ -195,27 +293,58 @@ struct ltt_kernel_context *trace_kernel_create_context(
 	if (ctx) {
 		memcpy(&kctx->ctx, ctx, sizeof(kctx->ctx));
 	}
-
 error:
 	return kctx;
 }
 
+/*
+ * Allocate and init a kernel context object from an existing kernel context
+ * object.
+ *
+ * Return the allocated object or NULL on error.
+ */
+struct ltt_kernel_context *trace_kernel_copy_context(
+		struct ltt_kernel_context *kctx)
+{
+	struct ltt_kernel_context *kctx_copy;
+
+	assert(kctx);
+	kctx_copy = zmalloc(sizeof(*kctx_copy));
+	if (!kctx_copy) {
+		PERROR("zmalloc ltt_kernel_context");
+		goto error;
+	}
+
+	memcpy(kctx_copy, kctx, sizeof(*kctx_copy));
+	memset(&kctx_copy->list, 0, sizeof(kctx_copy->list));
+
+error:
+	return kctx_copy;
+}
+
 /*
  * Allocate and initialize a kernel event. Set name and event type.
+ * We own filter_expression, and filter.
  *
  * Return pointer to structure or NULL.
  */
-struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
+enum lttng_error_code trace_kernel_create_event(
+		struct lttng_event *ev, char *filter_expression,
+		struct lttng_bytecode *filter,
+		struct ltt_kernel_event **kernel_event)
 {
-	struct ltt_kernel_event *lke;
+	enum lttng_error_code ret;
 	struct lttng_kernel_event *attr;
+	struct ltt_kernel_event *local_kernel_event;
+	struct lttng_userspace_probe_location *userspace_probe_location = NULL;
 
 	assert(ev);
 
-	lke = zmalloc(sizeof(struct ltt_kernel_event));
+	local_kernel_event = zmalloc(sizeof(struct ltt_kernel_event));
 	attr = zmalloc(sizeof(struct lttng_kernel_event));
-	if (lke == NULL || attr == NULL) {
+	if (local_kernel_event == NULL || attr == NULL) {
 		PERROR("kernel event zmalloc");
+		ret = LTTNG_ERR_NOMEM;
 		goto error;
 	}
 
@@ -228,6 +357,70 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 				ev->attr.probe.symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
 		attr->u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 		break;
+	case LTTNG_EVENT_USERSPACE_PROBE:
+	{
+		const struct lttng_userspace_probe_location* location = NULL;
+		const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+
+		location = lttng_event_get_userspace_probe_location(ev);
+		if (!location) {
+			ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+
+		/*
+		 * From this point on, the specific term 'uprobe' is used
+		 * instead of the generic 'userspace probe' because it's the
+		 * technology used at the moment for this instrumentation.
+		 * LTTng currently implements userspace probes using uprobes.
+		 * In the interactions with the kernel tracer, we use the
+		 * uprobe term.
+		 */
+		attr->instrumentation = LTTNG_KERNEL_UPROBE;
+
+		lookup = lttng_userspace_probe_location_get_lookup_method(
+				location);
+		if (!lookup) {
+			ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+
+		/*
+		 * From the kernel tracer's perspective, all userspace probe
+		 * event types are all the same: a file and an offset.
+		 */
+		switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+		case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+			/* Get the file descriptor on the target binary. */
+			attr->u.uprobe.fd =
+					lttng_userspace_probe_location_function_get_binary_fd(location);
+
+			/*
+			 * Save a reference to the probe location used during
+			 * the listing of events.
+			 */
+			userspace_probe_location =
+					lttng_userspace_probe_location_copy(location);
+			break;
+		case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+			/* Get the file descriptor on the target binary. */
+			attr->u.uprobe.fd =
+					lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
+
+			/*
+			 * Save a reference to the probe location used during the listing of
+			 * events.
+			 */
+			userspace_probe_location =
+					lttng_userspace_probe_location_copy(location);
+			break;
+		default:
+			DBG("Unsupported lookup method type");
+			ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+		break;
+	}
 	case LTTNG_EVENT_FUNCTION:
 		attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
 		attr->u.kretprobe.addr = ev->attr.probe.addr;
@@ -247,12 +440,16 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 		break;
 	case LTTNG_EVENT_SYSCALL:
 		attr->instrumentation = LTTNG_KERNEL_SYSCALL;
+		attr->u.syscall.abi = LTTNG_KERNEL_SYSCALL_ABI_ALL;
+		attr->u.syscall.entryexit = LTTNG_KERNEL_SYSCALL_ENTRYEXIT;
+		attr->u.syscall.match = LTTNG_KERNEL_SYSCALL_MATCH_NAME;
 		break;
 	case LTTNG_EVENT_ALL:
 		attr->instrumentation = LTTNG_KERNEL_ALL;
 		break;
 	default:
 		ERR("Unknown kernel instrumentation type (%d)", ev->type);
+		ret = LTTNG_ERR_INVALID;
 		goto error;
 	}
 
@@ -261,18 +458,252 @@ struct ltt_kernel_event *trace_kernel_create_event(struct lttng_event *ev)
 	attr->name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
 
 	/* Setting up a kernel event */
-	lke->fd = -1;
-	lke->event = attr;
-	lke->enabled = 1;
+	local_kernel_event->fd = -1;
+	local_kernel_event->event = attr;
+	local_kernel_event->enabled = 1;
+	local_kernel_event->filter_expression = filter_expression;
+	local_kernel_event->filter = filter;
+	local_kernel_event->userspace_probe_location = userspace_probe_location;
 
-	return lke;
+	*kernel_event = local_kernel_event;
+
+	return LTTNG_OK;
 
 error:
-	free(lke);
+	free(filter_expression);
+	free(filter);
+	free(local_kernel_event);
 	free(attr);
-	return NULL;
+	return ret;
 }
 
+/*
+ * Allocate and initialize a kernel token event rule.
+ *
+ * Return pointer to structure or NULL.
+ */
+enum lttng_error_code trace_kernel_create_event_notifier_rule(
+		struct lttng_trigger *trigger,
+		uint64_t token,
+		struct ltt_kernel_event_notifier_rule **event_notifier_rule)
+{
+	enum lttng_error_code ret = LTTNG_OK;
+	enum lttng_condition_type condition_type;
+	enum lttng_event_rule_type event_rule_type;
+	enum lttng_condition_status condition_status;
+	struct ltt_kernel_event_notifier_rule *local_kernel_token_event_rule;
+	const struct lttng_condition *condition = NULL;
+	const struct lttng_event_rule *event_rule = NULL;
+
+	assert(event_notifier_rule);
+
+	condition = lttng_trigger_get_const_condition(trigger);
+	assert(condition);
+
+	condition_type = lttng_condition_get_type(condition);
+	assert(condition_type == LTTNG_CONDITION_TYPE_ON_EVENT);
+
+	condition_status = lttng_condition_on_event_get_rule(
+			condition, &event_rule);
+	assert(condition_status == LTTNG_CONDITION_STATUS_OK);
+	assert(event_rule);
+
+	event_rule_type = lttng_event_rule_get_type(event_rule);
+	assert(event_rule_type != LTTNG_EVENT_RULE_TYPE_UNKNOWN);
+
+	local_kernel_token_event_rule =
+			zmalloc(sizeof(struct ltt_kernel_event_notifier_rule));
+	if (local_kernel_token_event_rule == NULL) {
+		PERROR("Failed to allocate ltt_kernel_token_event_rule structure");
+		ret = LTTNG_ERR_NOMEM;
+		goto error;
+	}
+
+	local_kernel_token_event_rule->fd = -1;
+	local_kernel_token_event_rule->enabled = 1;
+	local_kernel_token_event_rule->token = token;
+
+	/* Get the reference of the event rule. */
+	lttng_trigger_get(trigger);
+
+	local_kernel_token_event_rule->trigger = trigger;
+	/* The event rule still owns the filter and bytecode. */
+	local_kernel_token_event_rule->filter =
+			lttng_event_rule_get_filter_bytecode(event_rule);
+
+	DBG3("Created kernel event notifier rule: token =  %" PRIu64,
+			local_kernel_token_event_rule->token);
+error:
+	*event_notifier_rule = local_kernel_token_event_rule;
+	return ret;
+}
+
+/*
+ * Initialize a kernel trigger from an event rule.
+ */
+enum lttng_error_code trace_kernel_init_event_notifier_from_event_rule(
+		const struct lttng_event_rule *rule,
+		struct lttng_kernel_event_notifier *kernel_event_notifier)
+{
+	enum lttng_error_code ret_code;
+	const char *name;
+	int strncpy_ret;
+
+	switch (lttng_event_rule_get_type(rule)) {
+	case LTTNG_EVENT_RULE_TYPE_KERNEL_PROBE:
+	{
+		uint64_t address = 0, offset = 0;
+		const char *symbol_name = NULL;
+		const struct lttng_kernel_probe_location *location = NULL;
+		enum lttng_kernel_probe_location_status k_status;
+		enum lttng_event_rule_status status;
+
+		status = lttng_event_rule_kernel_probe_get_location(rule, &location);
+		if (status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+
+		switch (lttng_kernel_probe_location_get_type(location)) {
+		case LTTNG_KERNEL_PROBE_LOCATION_TYPE_ADDRESS:
+		{
+			k_status = lttng_kernel_probe_location_address_get_address(
+					location, &address);
+			assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
+			break;
+		}
+		case LTTNG_KERNEL_PROBE_LOCATION_TYPE_SYMBOL_OFFSET:
+		{
+			k_status = lttng_kernel_probe_location_symbol_get_offset(
+					location, &offset);
+			assert(k_status == LTTNG_KERNEL_PROBE_LOCATION_STATUS_OK);
+			symbol_name = lttng_kernel_probe_location_symbol_get_name(
+					location);
+			break;
+		}
+		default:
+			abort();
+		}
+
+		kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_KPROBE;
+		kernel_event_notifier->event.u.kprobe.addr = address;
+		kernel_event_notifier->event.u.kprobe.offset = offset;
+		if (symbol_name) {
+			strncpy_ret = lttng_strncpy(
+					kernel_event_notifier->event.u.kprobe.symbol_name,
+					symbol_name, LTTNG_KERNEL_SYM_NAME_LEN);
+
+			if (strncpy_ret) {
+				ret_code = LTTNG_ERR_INVALID;
+				goto error;
+			}
+		}
+
+		kernel_event_notifier->event.u.kprobe.symbol_name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
+
+		status = lttng_event_rule_kernel_probe_get_event_name(rule, &name);
+		assert(status == LTTNG_EVENT_RULE_STATUS_OK);
+		ret_code = LTTNG_OK;
+		break;
+	}
+	case LTTNG_EVENT_RULE_TYPE_USERSPACE_PROBE:
+	{
+		const struct lttng_userspace_probe_location* location = NULL;
+		const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+		enum lttng_event_rule_status status;
+
+		status = lttng_event_rule_userspace_probe_get_location(rule, &location);
+		if (status != LTTNG_EVENT_RULE_STATUS_OK) {
+			ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+
+		kernel_event_notifier->event.instrumentation = LTTNG_KERNEL_UPROBE;
+
+		lookup = lttng_userspace_probe_location_get_lookup_method(
+				location);
+		if (!lookup) {
+			ret_code = LTTNG_ERR_PROBE_LOCATION_INVAL;
+			goto error;
+		}
+
+		/*
+		 * From the kernel tracer's perspective, all userspace probe
+		 * event types are all the same: a file and an offset.
+		 */
+		switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+		case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+			/* Get the file descriptor on the target binary. */
+			kernel_event_notifier->event.u.uprobe.fd =
+					lttng_userspace_probe_location_function_get_binary_fd(location);
+
+			break;
+		case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+			/* Get the file descriptor on the target binary. */
+			kernel_event_notifier->event.u.uprobe.fd =
+					lttng_userspace_probe_location_tracepoint_get_binary_fd(location);
+			break;
+		default:
+			abort();
+		}
+
+		status = lttng_event_rule_userspace_probe_get_event_name(
+				rule, &name);
+		assert(status == LTTNG_EVENT_RULE_STATUS_OK);
+		ret_code = LTTNG_OK;
+		break;
+	}
+	case LTTNG_EVENT_RULE_TYPE_TRACEPOINT:
+	{
+		const enum lttng_domain_type domain =
+				lttng_event_rule_get_domain_type(rule);
+		const enum lttng_event_rule_status status =
+				lttng_event_rule_tracepoint_get_pattern(
+						rule, &name);
+
+		assert(domain == LTTNG_DOMAIN_KERNEL);
+		assert(status == LTTNG_EVENT_RULE_STATUS_OK);
+		kernel_event_notifier->event.instrumentation =
+				LTTNG_KERNEL_TRACEPOINT;
+
+		ret_code = LTTNG_OK;
+		break;
+	}
+	case LTTNG_EVENT_RULE_TYPE_SYSCALL:
+	{
+		const enum lttng_event_rule_status status =
+				lttng_event_rule_syscall_get_pattern(
+						rule, &name);
+
+		assert(status == LTTNG_EVENT_RULE_STATUS_OK);
+
+		kernel_event_notifier->event.instrumentation =
+				LTTNG_KERNEL_SYSCALL;
+		kernel_event_notifier->event.u.syscall.abi =
+				LTTNG_KERNEL_SYSCALL_ABI_ALL;
+		kernel_event_notifier->event.u.syscall.entryexit =
+				LTTNG_KERNEL_SYSCALL_ENTRY;
+		kernel_event_notifier->event.u.syscall.match =
+				LTTNG_KERNEL_SYSCALL_MATCH_NAME;
+		ret_code = LTTNG_OK;
+		break;
+	}
+	case LTTNG_EVENT_RULE_TYPE_KERNEL_FUNCTION:
+	default:
+		abort();
+		break;
+	}
+
+	strncpy_ret = lttng_strncpy(kernel_event_notifier->event.name, name,
+			LTTNG_KERNEL_SYM_NAME_LEN);
+	if (strncpy_ret) {
+		ret_code = LTTNG_ERR_INVALID;
+		goto error;
+	}
+
+error:
+	return ret_code;
+}
 /*
  * Allocate and initialize a kernel metadata.
  *
@@ -280,6 +711,7 @@ error:
  */
 struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 {
+	int ret;
 	struct ltt_kernel_metadata *lkm;
 	struct lttng_channel *chan;
 
@@ -290,13 +722,38 @@ struct ltt_kernel_metadata *trace_kernel_create_metadata(void)
 		goto error;
 	}
 
+	ret = lttng_strncpy(
+			chan->name, DEFAULT_METADATA_NAME, sizeof(chan->name));
+	if (ret) {
+		ERR("Failed to initialize metadata channel name to `%s`",
+				DEFAULT_METADATA_NAME);
+		goto error;
+	}
+
 	/* Set default attributes */
-	chan->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
+	chan->attr.overwrite = DEFAULT_METADATA_OVERWRITE;
 	chan->attr.subbuf_size = default_get_metadata_subbuf_size();
 	chan->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
-	chan->attr.switch_timer_interval = DEFAULT_KERNEL_CHANNEL_SWITCH_TIMER;
-	chan->attr.read_timer_interval = DEFAULT_KERNEL_CHANNEL_READ_TIMER;
-	chan->attr.output = DEFAULT_KERNEL_CHANNEL_OUTPUT;
+	chan->attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
+	chan->attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;;
+
+
+	/*
+	 * The metadata channel of kernel sessions must use the "mmap"
+	 * back-end since the consumer daemon accumulates complete
+	 * metadata units before sending them to the relay daemon in
+	 * live mode. The consumer daemon also needs to extract the contents
+	 * of the metadata cache when computing a rotation position.
+	 *
+	 * In both cases, it is not possible to rely on the splice
+	 * back-end as the consumer daemon may need to accumulate more
+	 * content than can be backed by the ring buffer's underlying
+	 * pages.
+	 */
+	chan->attr.output = LTTNG_EVENT_MMAP;
+	chan->attr.tracefile_size = 0;
+	chan->attr.tracefile_count = 0;
+	chan->attr.live_timer_interval = 0;
 
 	/* Init metadata */
 	lkm->fd = -1;
@@ -389,16 +846,51 @@ void trace_kernel_destroy_event(struct ltt_kernel_event *event)
 			PERROR("close");
 		}
 	} else {
-		DBG("[trace] Tearing down event (no associated fd)");
+		DBG("[trace] Tearing down event (no associated file descriptor)");
 	}
 
 	/* Remove from event list */
 	cds_list_del(&event->list);
 
+	free(event->filter_expression);
+	free(event->filter);
+
 	free(event->event);
 	free(event);
 }
 
+/*
+ * Cleanup kernel event structure.
+ */
+static void free_token_event_rule_rcu(struct rcu_head *rcu_node)
+{
+	struct ltt_kernel_event_notifier_rule *rule = caa_container_of(rcu_node,
+			struct ltt_kernel_event_notifier_rule, rcu_node);
+
+	free(rule);
+}
+
+void trace_kernel_destroy_event_notifier_rule(
+		struct ltt_kernel_event_notifier_rule *event)
+{
+	assert(event);
+
+	if (event->fd >= 0) {
+		const int ret = close(event->fd);
+
+		DBG("Closing kernel event notifier rule file descriptor: fd = %d",
+				event->fd);
+		if (ret) {
+			PERROR("Failed to close kernel event notifier file descriptor: fd = %d",
+					event->fd);
+		}
+	} else {
+		DBG("Destroying kernel event notifier rule (no associated file descriptor)");
+	}
+
+	lttng_trigger_put(event->trigger);
+	call_rcu(&event->rcu_node, free_token_event_rule_rcu);
+}
 /*
  * Cleanup kernel context structure.
  */
@@ -406,7 +898,9 @@ void trace_kernel_destroy_context(struct ltt_kernel_context *ctx)
 {
 	assert(ctx);
 
-	cds_list_del(&ctx->list);
+	if (ctx->in_list) {
+		cds_list_del(&ctx->list);
+	}
 	free(ctx);
 }
 
@@ -419,6 +913,7 @@ void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 	struct ltt_kernel_event *event, *etmp;
 	struct ltt_kernel_context *ctx, *ctmp;
 	int ret;
+	enum lttng_error_code status;
 
 	assert(channel);
 
@@ -449,6 +944,14 @@ void trace_kernel_destroy_channel(struct ltt_kernel_channel *channel)
 	/* Remove from channel list */
 	cds_list_del(&channel->list);
 
+	if (notification_thread_handle
+			&& channel->published_to_notification_thread) {
+		status = notification_thread_command_remove_channel(
+				notification_thread_handle,
+				channel->key, LTTNG_DOMAIN_KERNEL);
+		assert(status == LTTNG_OK);
+	}
+	free(channel->channel->attr.extended.ptr);
 	free(channel->channel);
 	free(channel);
 }
@@ -511,10 +1014,20 @@ void trace_kernel_destroy_session(struct ltt_kernel_session *session)
 	cds_list_for_each_entry_safe(channel, ctmp, &session->channel_list.head, list) {
 		trace_kernel_destroy_channel(channel);
 	}
+}
 
+/* Free elements needed by destroy notifiers. */
+void trace_kernel_free_session(struct ltt_kernel_session *session)
+{
 	/* Wipe consumer output object */
-	consumer_destroy_output(session->consumer);
-	consumer_destroy_output(session->tmp_consumer);
+	consumer_output_put(session->consumer);
+
+	process_attr_tracker_destroy(session->tracker_pid);
+	process_attr_tracker_destroy(session->tracker_vpid);
+	process_attr_tracker_destroy(session->tracker_uid);
+	process_attr_tracker_destroy(session->tracker_vuid);
+	process_attr_tracker_destroy(session->tracker_gid);
+	process_attr_tracker_destroy(session->tracker_vgid);
 
 	free(session);
 }