X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Faction-executor.c;fp=src%2Fbin%2Flttng-sessiond%2Faction-executor.c;h=40686eb7b0b77aea4636ad003bf3fb9ccbd08174;hp=0000000000000000000000000000000000000000;hb=1831ae68b70dece8e9b847081526495adbbf05e5;hpb=25357057de5ae4dd2a572e8f9b893c1b90cbd60a

diff --git a/src/bin/lttng-sessiond/action-executor.c b/src/bin/lttng-sessiond/action-executor.c
new file mode 100644
index 000000000..40686eb7b
--- /dev/null
+++ b/src/bin/lttng-sessiond/action-executor.c
@@ -0,0 +1,654 @@
+/*
+ * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include "action-executor.h"
+#include "cmd.h"
+#include "health-sessiond.h"
+#include "lttng-sessiond.h"
+#include "notification-thread-internal.h"
+#include "session.h"
+#include "thread.h"
+#include <common/macros.h>
+#include <lttng/action/group.h>
+#include <lttng/action/notify.h>
+#include <lttng/action/rotate-session.h>
+#include <lttng/action/snapshot-session.h>
+#include <lttng/action/start-session.h>
+#include <lttng/action/stop-session.h>
+#include <lttng/condition/evaluation.h>
+#include <lttng/condition/event-rule-internal.h>
+#include <lttng/lttng-error.h>
+#include <lttng/trigger/trigger-internal.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <urcu/list.h>
+
+#define THREAD_NAME "Action Executor"
+#define MAX_QUEUED_WORK_COUNT 8192
+
+struct action_work_item {
+	uint64_t id;
+	struct lttng_trigger *trigger;
+	struct notification_client_list *client_list;
+	struct cds_list_head list_node;
+};
+
+struct action_executor {
+	struct lttng_thread *thread;
+	struct notification_thread_handle *notification_thread_handle;
+	struct {
+		uint64_t pending_count;
+		struct cds_list_head list;
+		pthread_cond_t cond;
+		pthread_mutex_t lock;
+	} work;
+	bool should_quit;
+	uint64_t next_work_item_id;
+};
+
+typedef int (*action_executor_handler)(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *action);
+
+static int action_executor_notify_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_start_session_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_stop_session_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_rotate_session_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_snapshot_session_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_group_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+static int action_executor_generic_handler(struct action_executor *executor,
+		const struct action_work_item *,
+		const struct lttng_action *);
+
+static const action_executor_handler action_executors[] = {
+	[LTTNG_ACTION_TYPE_NOTIFY] = action_executor_notify_handler,
+	[LTTNG_ACTION_TYPE_START_SESSION] = action_executor_start_session_handler,
+	[LTTNG_ACTION_TYPE_STOP_SESSION] = action_executor_stop_session_handler,
+	[LTTNG_ACTION_TYPE_ROTATE_SESSION] = action_executor_rotate_session_handler,
+	[LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = action_executor_snapshot_session_handler,
+	[LTTNG_ACTION_TYPE_GROUP] = action_executor_group_handler,
+};
+
+static const char *get_action_name(const struct lttng_action *action)
+{
+	const char *action_type_names[] = {
+		[LTTNG_ACTION_TYPE_NOTIFY] = "Notify",
+		[LTTNG_ACTION_TYPE_START_SESSION] = "Start session",
+		[LTTNG_ACTION_TYPE_STOP_SESSION] = "Stop session",
+		[LTTNG_ACTION_TYPE_ROTATE_SESSION] = "Rotate session",
+		[LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = "Snapshot session",
+		[LTTNG_ACTION_TYPE_GROUP] = "Group",
+	};
+
+	return action_type_names[lttng_action_get_type(action)];
+}
+
+static const char *get_trigger_name(const struct lttng_trigger *trigger)
+{
+	const char *trigger_name;
+	enum lttng_trigger_status trigger_status;
+
+	trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+	assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+	return trigger_name;
+}
+
+static int client_handle_transmission_status(
+		struct notification_client *client,
+		enum client_transmission_status status,
+		void *user_data)
+{
+	struct action_executor *executor = user_data;
+
+	switch (status) {
+	case CLIENT_TRANSMISSION_STATUS_COMPLETE:
+		DBG("Sent notification to client");
+		break;
+	default:
+		ERR("Could not send notification to client");
+	}
+
+	return 0;
+}
+
+static int action_executor_notify_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	int ret = 0;
+	struct lttng_evaluation *evaluation = NULL;
+
+	assert(work_item->client_list);
+
+	evaluation = lttng_evaluation_event_rule_create(
+			get_trigger_name(work_item->trigger));
+	if (!evaluation) {
+		ERR("Failed to create event rule hit evaluation");
+		ret = -1;
+		goto end;
+	}
+
+	ret = notification_client_list_send_evaluation(work_item->client_list,
+			lttng_trigger_get_const_condition(work_item->trigger),
+			evaluation,
+			lttng_trigger_get_credentials(work_item->trigger), NULL,
+			client_handle_transmission_status, executor);
+end:
+	lttng_evaluation_destroy(evaluation);
+	return ret;
+}
+
+static int action_executor_start_session_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	int ret = 0;
+	const char *session_name;
+	enum lttng_action_status action_status;
+	struct ltt_session *session;
+
+	action_status = lttng_action_start_session_get_session_name(
+			action, &session_name);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR("Failed to get session name from \"%s\" action",
+				get_action_name(action));
+		ret = -1;
+		goto end;
+	}
+
+	session_lock_list();
+	session = session_find_by_name(session_name);
+	if (session) {
+		enum lttng_error_code cmd_ret;
+
+		session_lock(session);
+		cmd_ret = cmd_start_trace(session);
+		session_unlock(session);
+
+		switch (cmd_ret) {
+		case LTTNG_OK:
+			DBG("Successfully started session \"%s\" on behalf of trigger \"%s\"",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		case LTTNG_ERR_TRACE_ALREADY_STARTED:
+			DBG("Attempted to start session \"%s\" on behalf of trigger \"%s\" but it was already started",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		default:
+			WARN("Failed to start session \"%s\" on behalf of trigger \"%s\": %s",
+					session_name,
+					get_trigger_name(work_item->trigger),
+					lttng_strerror(-cmd_ret));
+			break;
+		}
+		session_put(session);
+	} else {
+		DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
+				session_name, get_action_name(action),
+				get_trigger_name(work_item->trigger));
+	}
+	session_unlock_list();
+end:
+	return ret;
+}
+
+static int action_executor_stop_session_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	int ret = 0;
+	const char *session_name;
+	enum lttng_action_status action_status;
+	struct ltt_session *session;
+
+	action_status = lttng_action_stop_session_get_session_name(
+			action, &session_name);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR("Failed to get session name from \"%s\" action",
+				get_action_name(action));
+		ret = -1;
+		goto end;
+	}
+
+	session_lock_list();
+	session = session_find_by_name(session_name);
+	if (session) {
+		enum lttng_error_code cmd_ret;
+
+		session_lock(session);
+		cmd_ret = cmd_stop_trace(session);
+		session_unlock(session);
+
+		switch (cmd_ret) {
+		case LTTNG_OK:
+			DBG("Successfully stopped session \"%s\" on behalf of trigger \"%s\"",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		case LTTNG_ERR_TRACE_ALREADY_STOPPED:
+			DBG("Attempted to stop session \"%s\" on behalf of trigger \"%s\" but it was already stopped",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		default:
+			WARN("Failed to stop session \"%s\" on behalf of trigger \"%s\": %s",
+					session_name,
+					get_trigger_name(work_item->trigger),
+					lttng_strerror(-cmd_ret));
+			break;
+		}
+		session_put(session);
+	} else {
+		DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
+				session_name, get_action_name(action),
+				get_trigger_name(work_item->trigger));
+	}
+	session_unlock_list();
+end:
+	return ret;
+}
+
+static int action_executor_rotate_session_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	int ret = 0;
+	const char *session_name;
+	enum lttng_action_status action_status;
+	struct ltt_session *session;
+
+	action_status = lttng_action_rotate_session_get_session_name(
+			action, &session_name);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR("Failed to get session name from \"%s\" action",
+				get_action_name(action));
+		ret = -1;
+		goto end;
+	}
+
+	session_lock_list();
+	session = session_find_by_name(session_name);
+	if (session) {
+		enum lttng_error_code cmd_ret;
+
+		session_lock(session);
+		cmd_ret = cmd_rotate_session(session, NULL, false,
+				LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
+		session_unlock(session);
+
+		switch (cmd_ret) {
+		case LTTNG_OK:
+			DBG("Successfully started rotation of session \"%s\" on behalf of trigger \"%s\"",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		case LTTNG_ERR_ROTATION_PENDING:
+			DBG("Attempted to start a rotation of session \"%s\" on behalf of trigger \"%s\" but a rotation is already ongoing",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		case LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP:
+		case LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR:
+			DBG("Attempted to start a rotation of session \"%s\" on behalf of trigger \"%s\" but a rotation has already been completed since the last stop or clear",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		default:
+			WARN("Failed to start a rotation of session \"%s\" on behalf of trigger \"%s\": %s",
+					session_name,
+					get_trigger_name(work_item->trigger),
+					lttng_strerror(-cmd_ret));
+			break;
+		}
+		session_put(session);
+	} else {
+		DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
+				session_name, get_action_name(action),
+				get_trigger_name(work_item->trigger));
+	}
+	session_unlock_list();
+end:
+	return ret;
+}
+
+static int action_executor_snapshot_session_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	int ret = 0;
+	const char *session_name;
+	enum lttng_action_status action_status;
+	struct ltt_session *session;
+	const struct lttng_snapshot_output default_snapshot_output = {
+		.max_size = UINT64_MAX,
+	};
+	const struct lttng_snapshot_output *snapshot_output =
+			&default_snapshot_output;
+
+	action_status = lttng_action_snapshot_session_get_session_name(
+			action, &session_name);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		ERR("Failed to get session name from \"%s\" action",
+				get_action_name(action));
+		ret = -1;
+		goto end;
+	}
+
+	action_status = lttng_action_snapshot_session_get_output_const(
+			action, &snapshot_output);
+	if (action_status != LTTNG_ACTION_STATUS_OK &&
+			action_status != LTTNG_ACTION_STATUS_UNSET) {
+		ERR("Failed to get output from \"%s\" action",
+				get_action_name(action));
+		ret = -1;
+		goto end;
+	}
+
+	session_lock_list();
+	session = session_find_by_name(session_name);
+	if (session) {
+		enum lttng_error_code cmd_ret;
+
+		session_lock(session);
+		cmd_ret = cmd_snapshot_record(session, snapshot_output, 0);
+		session_unlock(session);
+
+		switch (cmd_ret) {
+		case LTTNG_OK:
+			DBG("Successfully recorded snapshot of session \"%s\" on behalf of trigger \"%s\"",
+					session_name,
+					get_trigger_name(work_item->trigger));
+			break;
+		default:
+			WARN("Failed to record snapshot of session \"%s\" on behalf of trigger \"%s\": %s",
+					session_name,
+					get_trigger_name(work_item->trigger),
+					lttng_strerror(-cmd_ret));
+			break;
+		}
+		session_put(session);
+	} else {
+		DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
+				session_name, get_action_name(action),
+				get_trigger_name(work_item->trigger));
+	}
+	session_unlock_list();
+end:
+	return ret;
+}
+
+static int action_executor_group_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action_group)
+{
+	int ret = 0;
+	unsigned int i, count;
+	enum lttng_action_status action_status;
+
+	action_status = lttng_action_group_get_count(action_group, &count);
+	if (action_status != LTTNG_ACTION_STATUS_OK) {
+		/* Fatal error. */
+		ERR("Failed to get count of action in action group");
+		ret = -1;
+		goto end;
+	}
+
+	DBG("Action group has %u action%s", count, count != 1 ? "s" : "");
+	for (i = 0; i < count; i++) {
+		const struct lttng_action *action =
+				lttng_action_group_get_at_index_const(
+						action_group, i);
+
+		ret = action_executor_generic_handler(
+				executor, work_item, action);
+		if (ret) {
+			ERR("Stopping the execution of the action group of trigger \"%s\" following a fatal error",
+					get_trigger_name(work_item->trigger));
+			goto end;
+		}
+	}
+end:
+	return ret;
+}
+
+static int action_executor_generic_handler(struct action_executor *executor,
+		const struct action_work_item *work_item,
+		const struct lttng_action *action)
+{
+	DBG("Executing action \"%s\" of trigger \"%s\" action work item %" PRIu64,
+			get_action_name(action),
+			get_trigger_name(work_item->trigger),
+			work_item->id);
+
+	return action_executors[lttng_action_get_type(action)](
+			executor, work_item, action);
+}
+
+static int action_work_item_execute(struct action_executor *executor,
+		struct action_work_item *work_item)
+{
+	int ret;
+	const struct lttng_action *action =
+			lttng_trigger_get_const_action(work_item->trigger);
+
+	DBG("Starting execution of action work item %" PRIu64 " of trigger \"%s\"",
+			work_item->id, get_trigger_name(work_item->trigger));
+	ret = action_executor_generic_handler(executor, work_item, action);
+	DBG("Completed execution of action work item %" PRIu64 " of trigger \"%s\"",
+			work_item->id, get_trigger_name(work_item->trigger));
+	return ret;
+}
+
+static void action_work_item_destroy(struct action_work_item *work_item)
+{
+	lttng_trigger_put(work_item->trigger);
+	notification_client_list_put(work_item->client_list);
+	free(work_item);
+}
+
+static void *action_executor_thread(void *_data)
+{
+	struct action_executor *executor = _data;
+
+	assert(executor);
+
+	health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ACTION_EXECUTOR);
+
+	rcu_register_thread();
+	rcu_thread_online();
+
+	DBG("Entering work execution loop");
+	pthread_mutex_lock(&executor->work.lock);
+	while (!executor->should_quit) {
+		int ret;
+		struct action_work_item *work_item;
+
+		health_code_update();
+		if (executor->work.pending_count == 0) {
+			health_poll_entry();
+			DBG("No work items enqueued, entering wait");
+			pthread_cond_wait(&executor->work.cond,
+					&executor->work.lock);
+			DBG("Woke-up from wait");
+			health_poll_exit();
+			continue;
+		}
+
+		/* Pop item from front of the listwith work lock held. */
+		work_item = cds_list_first_entry(&executor->work.list,
+				struct action_work_item, list_node);
+		cds_list_del(&work_item->list_node);
+		executor->work.pending_count--;
+
+		/*
+		 * Work can be performed without holding the work lock,
+		 * allowing new items to be queued.
+		 */
+		pthread_mutex_unlock(&executor->work.lock);
+		ret = action_work_item_execute(executor, work_item);
+		action_work_item_destroy(work_item);
+		if (ret) {
+			/* Fatal error. */
+			break;
+		}
+		health_code_update();
+		pthread_mutex_lock(&executor->work.lock);
+	}
+	pthread_mutex_unlock(&executor->work.lock);
+	DBG("Left work execution loop");
+
+	health_code_update();
+
+	rcu_thread_offline();
+	rcu_unregister_thread();
+	health_unregister(health_sessiond);
+
+	return NULL;
+}
+
+static bool shutdown_action_executor_thread(void *_data)
+{
+	struct action_executor *executor = _data;
+
+	/* TODO. */
+	executor->should_quit = true;
+	pthread_cond_signal(&executor->work.cond);
+	return true;
+}
+
+static void clean_up_action_executor_thread(void *_data)
+{
+	struct action_executor *executor = _data;
+
+	assert(cds_list_empty(&executor->work.list));
+
+	pthread_mutex_destroy(&executor->work.lock);
+	pthread_cond_destroy(&executor->work.cond);
+	free(executor);
+}
+
+struct action_executor *action_executor_create(
+		struct notification_thread_handle *handle)
+{
+	struct action_executor *executor = zmalloc(sizeof(*executor));
+
+	if (!executor) {
+		goto end;
+	}
+
+	CDS_INIT_LIST_HEAD(&executor->work.list);
+	pthread_cond_init(&executor->work.cond, NULL);
+	pthread_mutex_init(&executor->work.lock, NULL);
+	executor->notification_thread_handle = handle;
+
+	executor->thread = lttng_thread_create(THREAD_NAME,
+			action_executor_thread, shutdown_action_executor_thread,
+			clean_up_action_executor_thread, executor);
+end:
+	return executor;
+}
+
+void action_executor_destroy(struct action_executor *executor)
+{
+	struct action_work_item *work_item, *tmp;
+
+	/* TODO Wait for work list to drain? */
+	lttng_thread_shutdown(executor->thread);
+	pthread_mutex_lock(&executor->work.lock);
+	if (executor->work.pending_count != 0) {
+		WARN("%" PRIu64
+			" trigger action%s still queued for execution and will be discarded",
+				executor->work.pending_count,
+				executor->work.pending_count == 1 ? " is" :
+								    "s are");
+	}
+
+	cds_list_for_each_entry_safe (
+			work_item, tmp, &executor->work.list, list_node) {
+		WARN("Discarding action work item %" PRIu64
+				" associated to trigger \"%s\"",
+				work_item->id, get_trigger_name(work_item->trigger));
+		cds_list_del(&work_item->list_node);
+		action_work_item_destroy(work_item);
+	}
+	pthread_mutex_unlock(&executor->work.lock);
+	lttng_thread_put(executor->thread);
+}
+
+/* RCU read-lock must be held by the caller. */
+enum action_executor_status action_executor_enqueue(
+		struct action_executor *executor,
+		struct lttng_trigger *trigger,
+		struct notification_client_list *client_list)
+{
+	enum action_executor_status executor_status = ACTION_EXECUTOR_STATUS_OK;
+	const uint64_t work_item_id = executor->next_work_item_id++;
+	struct action_work_item *work_item;
+	bool signal = false;
+
+	pthread_mutex_lock(&executor->work.lock);
+	/* Check for queue overflow. */
+	if (executor->work.pending_count >= MAX_QUEUED_WORK_COUNT) {
+		/* Most likely spammy, remove if it is the case. */
+		DBG("Refusing to enqueue action for trigger \"%s\" as work item %" PRIu64
+		    " (overflow)",
+				get_trigger_name(trigger), work_item_id);
+		executor_status = ACTION_EXECUTOR_STATUS_OVERFLOW;
+		goto error_unlock;
+	}
+
+	work_item = zmalloc(sizeof(*work_item));
+	if (!work_item) {
+		PERROR("Failed to allocate action executor work item on behalf of trigger \"%s\"",
+				get_trigger_name(trigger));
+		executor_status = ACTION_EXECUTOR_STATUS_ERROR;
+		goto error_unlock;
+	}
+
+	lttng_trigger_get(trigger);
+	if (client_list) {
+		const bool reference_acquired =
+				notification_client_list_get(client_list);
+
+		assert(reference_acquired);
+	}
+
+	*work_item = (typeof(*work_item)){
+			.id = work_item_id,
+			.trigger = trigger,
+			.client_list = client_list,
+			.list_node = CDS_LIST_HEAD_INIT(work_item->list_node),
+	};
+	cds_list_add_tail(&work_item->list_node, &executor->work.list);
+	executor->work.pending_count++;
+	DBG("Enqueued action for trigger \"%s\" as work item %" PRIu64,
+			get_trigger_name(trigger), work_item_id);
+	signal = true;
+
+error_unlock:
+	pthread_mutex_unlock(&executor->work.lock);
+	if (signal) {
+		pthread_cond_signal(&executor->work.cond);
+	}
+	return executor_status;
+}