+/*
+ * 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 <common/optional.h>
+#include <lttng/action/action-internal.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/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 lttng_evaluation *evaluation;
+ struct notification_client_list *client_list;
+ LTTNG_OPTIONAL(struct lttng_credentials) object_creds;
+ 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;
+};
+
+/*
+ * Only return non-zero on a fatal error that should shut down the action
+ * executor.
+ */
+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 *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",
+};
+
+static const char *get_action_name(const struct lttng_action *action)
+{
+ return action_type_names[lttng_action_get_type_const(action)];
+}
+
+/* Check if this trigger allowed to interect with a given session. */
+static bool is_trigger_allowed_for_session(const struct lttng_trigger *trigger,
+ struct ltt_session *session)
+{
+ bool is_allowed = false;
+ const struct lttng_credentials session_creds = {
+ .uid = session->uid,
+ .gid = session->gid,
+ };
+ /* Can never be NULL. */
+ const struct lttng_credentials *trigger_creds =
+ lttng_trigger_get_credentials(trigger);
+
+ is_allowed = (trigger_creds->uid == session_creds.uid) ||
+ (trigger_creds->uid == 0);
+ if (!is_allowed) {
+ WARN("Trigger is not allowed to interact with session `%s`: session uid = %ld, session gid = %ld, trigger uid = %ld, trigger gid = %ld",
+ session->name,
+ (long int) session->uid,
+ (long int) session->gid,
+ (long int) trigger_creds->uid,
+ (long int) trigger_creds->gid);
+ }
+
+ return is_allowed;
+}
+
+static int client_handle_transmission_status(
+ struct notification_client *client,
+ enum client_transmission_status status,
+ void *user_data)
+{
+ int ret = 0;
+ struct action_executor *executor = user_data;
+ bool update_communication = true;
+
+ ASSERT_LOCKED(client->lock);
+
+ switch (status) {
+ case CLIENT_TRANSMISSION_STATUS_COMPLETE:
+ DBG("Successfully sent full notification to client, client_id = %" PRIu64,
+ client->id);
+ update_communication = false;
+ break;
+ case CLIENT_TRANSMISSION_STATUS_QUEUED:
+ DBG("Queued notification in client outgoing buffer, client_id = %" PRIu64,
+ client->id);
+ break;
+ case CLIENT_TRANSMISSION_STATUS_FAIL:
+ DBG("Communication error occurred while sending notification to client, client_id = %" PRIu64,
+ client->id);
+ client->communication.active = false;
+ break;
+ default:
+ ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64,
+ client->id);
+ client->communication.active = false;
+ ret = -1;
+ goto end;
+ }
+
+ if (!update_communication) {
+ goto end;
+ }
+
+ ret = notification_thread_client_communication_update(
+ executor->notification_thread_handle, client->id,
+ status);
+end:
+ return ret;
+}
+
+static int action_executor_notify_handler(struct action_executor *executor,
+ const struct action_work_item *work_item,
+ const struct lttng_action *action)
+{
+ return notification_client_list_send_evaluation(work_item->client_list,
+ lttng_trigger_get_const_condition(work_item->trigger),
+ work_item->evaluation,
+ lttng_trigger_get_credentials(work_item->trigger),
+ LTTNG_OPTIONAL_GET_PTR(work_item->object_creds),
+ client_handle_transmission_status,
+ executor);
+}
+
+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;
+ enum lttng_error_code cmd_ret;
+
+ 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) {
+ DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
+ session_name, get_action_name(action),
+ work_item->trigger);
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = cmd_start_trace(session);
+ switch (cmd_ret) {
+ case LTTNG_OK:
+ DBG("Successfully started session `%s` on behalf of trigger `%p`",
+ session_name, work_item->trigger);
+ break;
+ case LTTNG_ERR_TRACE_ALREADY_STARTED:
+ DBG("Attempted to start session `%s` on behalf of trigger `%p` but it was already started",
+ session_name, work_item->trigger);
+ break;
+ default:
+ WARN("Failed to start session `%s` on behalf of trigger `%p`: %s",
+ session_name, work_item->trigger,
+ lttng_strerror(-cmd_ret));
+ break;
+ }
+
+error_dispose_session:
+ session_unlock(session);
+ session_put(session);
+error_unlock_list:
+ 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;
+ enum lttng_error_code cmd_ret;
+
+ 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) {
+ DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
+ session_name, get_action_name(action),
+ work_item->trigger);
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = cmd_stop_trace(session);
+ switch (cmd_ret) {
+ case LTTNG_OK:
+ DBG("Successfully stopped session `%s` on behalf of trigger `%p`",
+ session_name, work_item->trigger);
+ break;
+ case LTTNG_ERR_TRACE_ALREADY_STOPPED:
+ DBG("Attempted to stop session `%s` on behalf of trigger `%p` but it was already stopped",
+ session_name, work_item->trigger);
+ break;
+ default:
+ WARN("Failed to stop session `%s` on behalf of trigger `%p`: %s",
+ session_name, work_item->trigger,
+ lttng_strerror(-cmd_ret));
+ break;
+ }
+
+error_dispose_session:
+ session_unlock(session);
+ session_put(session);
+error_unlock_list:
+ 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;
+ enum lttng_error_code cmd_ret;
+
+ 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) {
+ DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
+ session_name, get_action_name(action),
+ work_item->trigger);
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = cmd_rotate_session(session, NULL, false,
+ LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
+ switch (cmd_ret) {
+ case LTTNG_OK:
+ DBG("Successfully started rotation of session `%s` on behalf of trigger `%p`",
+ session_name, work_item->trigger);
+ break;
+ case LTTNG_ERR_ROTATION_PENDING:
+ DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%p` but a rotation is already ongoing",
+ session_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 `%p` but a rotation has already been completed since the last stop or clear",
+ session_name, work_item->trigger);
+ break;
+ default:
+ WARN("Failed to start a rotation of session `%s` on behalf of trigger `%p`: %s",
+ session_name, work_item->trigger,
+ lttng_strerror(-cmd_ret));
+ break;
+ }
+
+error_dispose_session:
+ session_unlock(session);
+ session_put(session);
+error_unlock_list:
+ 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;
+ enum lttng_error_code cmd_ret;
+
+ 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(
+ 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) {
+ DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
+ session_name, get_action_name(action),
+ work_item->trigger);
+ goto error_unlock_list;
+ }
+
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = cmd_snapshot_record(session, snapshot_output, 0);
+ switch (cmd_ret) {
+ case LTTNG_OK:
+ DBG("Successfully recorded snapshot of session `%s` on behalf of trigger `%p`",
+ session_name, work_item->trigger);
+ break;
+ default:
+ WARN("Failed to record snapshot of session `%s` on behalf of trigger `%p`: %s",
+ session_name, work_item->trigger,
+ lttng_strerror(-cmd_ret));
+ break;
+ }
+
+error_dispose_session:
+ session_unlock(session);
+ session_put(session);
+error_unlock_list:
+ 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(
+ action_group, i);
+
+ ret = action_executor_generic_handler(
+ executor, work_item, action);
+ if (ret) {
+ ERR("Stopping the execution of the action group of trigger `%p` following a fatal error",
+ 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 `%p` action work item %" PRIu64,
+ get_action_name(action),
+ work_item->trigger,
+ work_item->id);
+
+ return action_executors[lttng_action_get_type_const(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 `%p`",
+ work_item->id, work_item->trigger);
+ ret = action_executor_generic_handler(executor, work_item, action);
+ DBG("Completed execution of action work item %" PRIu64 " of trigger `%p`",
+ work_item->id, work_item->trigger);
+ return ret;
+}
+
+static void action_work_item_destroy(struct action_work_item *work_item)
+{
+ lttng_trigger_put(work_item->trigger);
+ lttng_evaluation_destroy(work_item->evaluation);
+ 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;
+
+ 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 `%p`",
+ work_item->id, 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 lttng_evaluation *evaluation,
+ const struct lttng_credentials *object_creds,
+ 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 `%p` as work item %" PRIu64
+ " (overflow)",
+ 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 `%p`",
+ 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,
+ /* Ownership transferred to the work item. */
+ .evaluation = evaluation,
+ .object_creds = {
+ .is_set = !!object_creds,
+ .value = object_creds ? *object_creds :
+ (typeof(work_item->object_creds.value)) {},
+ },
+ .client_list = client_list,
+ .list_node = CDS_LIST_HEAD_INIT(work_item->list_node),
+ };
+
+ evaluation = NULL;
+ cds_list_add_tail(&work_item->list_node, &executor->work.list);
+ executor->work.pending_count++;
+ DBG("Enqueued action for trigger `%p` as work item %" PRIu64,
+ trigger, work_item_id);
+ signal = true;
+
+error_unlock:
+ pthread_mutex_unlock(&executor->work.lock);
+ if (signal) {
+ pthread_cond_signal(&executor->work.cond);
+ }
+
+ lttng_evaluation_destroy(evaluation);
+ return executor_status;
+}
projects / lttng-tools.git / commitdiff
