--- /dev/null
+/*
+ * 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/dynamic-array.h>
+#include <common/macros.h>
+#include <common/optional.h>
+#include <lttng/action/action-internal.h>
+#include <lttng/action/list-internal.h>
+#include <lttng/action/list.h>
+#include <lttng/action/notify-internal.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-matches-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
+
+/*
+ * A work item is composed of a dynamic array of sub-items which
+ * represent a flattened, and augmented, version of a trigger's actions.
+ *
+ * We cannot rely solely on the trigger's actions since each action can have an
+ * execution context we need to comply with.
+ *
+ * The notion of execution context is required since for some actions the
+ * associated object are referenced by name and not by id. This can lead to
+ * a number of ambiguities when executing an action work item.
+ *
+ * For example, let's take a simple trigger such as:
+ * - condition: ust event a
+ * - action: start session S
+ *
+ * At time T, session S exists.
+ * At T + 1, the event A is hit.
+ * At T + 2, the tracer event notification is received and the work item is
+ * queued. Here session S have an id of 1.
+ * At T + 3, the session S is destroyed and a new session S is created, with a
+ * resulting id of 200.
+ * At T +4, the work item is popped from the queue and begin execution and will
+ * start session S with an id of 200 instead of the session S id 1 that was
+ * present at the queuing phase.
+ *
+ * The context to be respected is the one when the work item is queued. If the
+ * execution context is not the same at the moment of execution, we skip the
+ * execution of that sub-item.
+ *
+ * It is the same policy in regards to the validity of the associated
+ * trigger object at the moment of execution, if the trigger is found to be
+ * unregistered, the execution is skipped.
+ */
+
+struct action_work_item {
+ uint64_t id;
+
+ /*
+ * The actions to be executed with their respective execution context.
+ * See struct `action_work_subitem`.
+ */
+ struct lttng_dynamic_array subitems;
+
+ /* Execution context data */
+ 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_work_subitem {
+ struct lttng_action *action;
+ struct {
+ /* Used by actions targeting a session. */
+ LTTNG_OPTIONAL(uint64_t) session_id;
+ } context;
+};
+
+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 *,
+ struct action_work_subitem *item);
+
+static int action_executor_notify_handler(struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_start_session_handler(
+ struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_stop_session_handler(
+ struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_rotate_session_handler(
+ struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_snapshot_session_handler(
+ struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_list_handler(struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+static int action_executor_generic_handler(struct action_executor *executor,
+ const struct action_work_item *,
+ struct action_work_subitem *);
+
+static const action_executor_handler action_executors[] = {
+ action_executor_notify_handler,
+ action_executor_start_session_handler,
+ action_executor_stop_session_handler,
+ action_executor_rotate_session_handler,
+ action_executor_snapshot_session_handler,
+ action_executor_list_handler,
+};
+
+/* Forward declaration */
+static int add_action_to_subitem_array(struct lttng_action *action,
+ struct lttng_dynamic_array *subitems);
+
+static int populate_subitem_array_from_trigger(struct lttng_trigger *trigger,
+ struct lttng_dynamic_array *subitems);
+
+static void action_work_subitem_destructor(void *element)
+{
+ struct action_work_subitem *subitem = (action_work_subitem *) element;
+
+ lttng_action_put(subitem->action);
+}
+
+static const char *get_action_name(const struct lttng_action *action)
+{
+ const enum lttng_action_type action_type = lttng_action_get_type(action);
+
+ LTTNG_ASSERT(action_type != LTTNG_ACTION_TYPE_UNKNOWN);
+
+ return lttng_action_type_string(action_type);
+}
+
+/* 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 = LTTNG_OPTIONAL_INIT_VALUE(session->uid),
+ .gid = LTTNG_OPTIONAL_INIT_VALUE(session->gid),
+ };
+ /* Can never be NULL. */
+ const struct lttng_credentials *trigger_creds =
+ lttng_trigger_get_credentials(trigger);
+
+ is_allowed = (lttng_credentials_is_equal_uid(trigger_creds, &session_creds)) ||
+ (lttng_credentials_get_uid(trigger_creds) == 0);
+ if (!is_allowed) {
+ WARN("Trigger is not allowed to interact with session `%s`: session uid = %ld, session gid = %ld, trigger uid = %ld",
+ session->name,
+ (long int) session->uid,
+ (long int) session->gid,
+ (long int) lttng_credentials_get_uid(trigger_creds));
+ }
+
+ return is_allowed;
+}
+
+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);
+ switch (trigger_status) {
+ case LTTNG_TRIGGER_STATUS_OK:
+ break;
+ case LTTNG_TRIGGER_STATUS_UNSET:
+ trigger_name = "(anonymous)";
+ break;
+ default:
+ trigger_name = "(failed to get name)";
+ break;
+ }
+
+ return trigger_name;
+}
+
+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 = (action_executor *) user_data;
+ bool update_communication = true;
+
+ 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);
+ break;
+ default:
+ ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64,
+ client->id);
+ ret = -1;
+ goto end;
+ }
+
+ if (!update_communication) {
+ goto end;
+ }
+
+ /* Safe to read client's id without locking as it is immutable. */
+ 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,
+ struct action_work_subitem *item)
+{
+ return notification_client_list_send_evaluation(work_item->client_list,
+ work_item->trigger,
+ work_item->evaluation,
+ work_item->object_creds.is_set ?
+ &(work_item->object_creds.value) :
+ NULL,
+ client_handle_transmission_status, executor);
+}
+
+static int action_executor_start_session_handler(
+ struct action_executor *executor,
+ const struct action_work_item *work_item,
+ struct action_work_subitem *item)
+{
+ int ret = 0;
+ const char *session_name;
+ enum lttng_action_status action_status;
+ struct ltt_session *session;
+ enum lttng_error_code cmd_ret;
+ struct lttng_action *action = item->action;
+
+ 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;
+ }
+
+ /*
+ * Validate if at the moment of the action was queued the session
+ * existed. If not skip the action altogether.
+ */
+ if (!item->context.session_id.is_set) {
+ DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ ret = 0;
+ 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 `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ goto error_unlock_list;
+ }
+
+ /*
+ * Check if the session id is the same as when the work item was
+ * enqueued.
+ */
+ if (session->id != LTTNG_OPTIONAL_GET(item->context.session_id)) {
+ DBG("Session id for session `%s` (id: %" PRIu64
+ " is not the same that was sampled (id: %" PRIu64
+ " at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, session->id,
+ LTTNG_OPTIONAL_GET(item->context.session_id),
+ get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ ret = 0;
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = (lttng_error_code) cmd_start_trace(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));
+ lttng_action_increase_execution_failure_count(action);
+ 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,
+ struct action_work_subitem *item)
+{
+ int ret = 0;
+ const char *session_name;
+ enum lttng_action_status action_status;
+ struct ltt_session *session;
+ enum lttng_error_code cmd_ret;
+ struct lttng_action *action = item->action;
+
+ 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;
+ }
+
+ /*
+ * Validate if, at the moment the action was queued, the target session
+ * existed. If not, skip the action altogether.
+ */
+ if (!item->context.session_id.is_set) {
+ DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ ret = 0;
+ 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 `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ goto error_unlock_list;
+ }
+
+ /*
+ * Check if the session id is the same as when the work item was
+ * enqueued
+ */
+ if (session->id != LTTNG_OPTIONAL_GET(item->context.session_id)) {
+ DBG("Session id for session `%s` (id: %" PRIu64
+ " is not the same that was sampled (id: %" PRIu64
+ " at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, session->id,
+ LTTNG_OPTIONAL_GET(item->context.session_id),
+ get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ ret = 0;
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = (lttng_error_code) cmd_stop_trace(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));
+ lttng_action_increase_execution_failure_count(action);
+ 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,
+ struct action_work_subitem *item)
+{
+ int ret = 0;
+ const char *session_name;
+ enum lttng_action_status action_status;
+ struct ltt_session *session;
+ enum lttng_error_code cmd_ret;
+ struct lttng_action *action = item->action;
+
+ 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;
+ }
+
+ /*
+ * Validate if, at the moment the action was queued, the target session
+ * existed. If not, skip the action altogether.
+ */
+ if (!item->context.session_id.is_set) {
+ DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ ret = 0;
+ 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 `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ goto error_unlock_list;
+ }
+
+ /*
+ * Check if the session id is the same as when the work item was
+ * enqueued.
+ */
+ if (session->id != LTTNG_OPTIONAL_GET(item->context.session_id)) {
+ DBG("Session id for session `%s` (id: %" PRIu64
+ " is not the same that was sampled (id: %" PRIu64
+ " at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, session->id,
+ LTTNG_OPTIONAL_GET(item->context.session_id),
+ get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ ret = 0;
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = (lttng_error_code) 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 `%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));
+ lttng_action_increase_execution_failure_count(action);
+ 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));
+ lttng_action_increase_execution_failure_count(action);
+ 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,
+ struct action_work_subitem *item)
+{
+ int ret = 0;
+ const char *session_name;
+ enum lttng_action_status action_status;
+ struct ltt_session *session;
+ lttng_snapshot_output default_snapshot_output;
+ const struct lttng_snapshot_output *snapshot_output =
+ &default_snapshot_output;
+ enum lttng_error_code cmd_ret;
+ struct lttng_action *action = item->action;
+
+ default_snapshot_output.max_size = UINT64_MAX;
+
+ /*
+ * Validate if, at the moment the action was queued, the target session
+ * existed. If not, skip the action altogether.
+ */
+ if (!item->context.session_id.is_set) {
+ DBG("Session was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
+ get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ ret = 0;
+ goto end;
+ }
+
+ 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 `%s`",
+ session_name, get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ lttng_action_increase_execution_failure_count(action);
+ goto error_unlock_list;
+ }
+
+ /*
+ * Check if the session id is the same as when the work item was
+ * enqueued.
+ */
+ if (session->id != LTTNG_OPTIONAL_GET(item->context.session_id)) {
+ DBG("Session id for session `%s` (id: %" PRIu64
+ " is not the same that was sampled (id: %" PRIu64
+ " at the moment the work item was enqueued for %s` action of trigger `%s`",
+ session_name, session->id,
+ LTTNG_OPTIONAL_GET(item->context.session_id),
+ get_action_name(action),
+ get_trigger_name(work_item->trigger));
+ ret = 0;
+ goto error_unlock_list;
+ }
+
+ session_lock(session);
+ if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
+ goto error_dispose_session;
+ }
+
+ cmd_ret = (lttng_error_code) cmd_snapshot_record(session, snapshot_output, 0);
+ 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));
+ lttng_action_increase_execution_failure_count(action);
+ break;
+ }
+
+error_dispose_session:
+ session_unlock(session);
+ session_put(session);
+error_unlock_list:
+ session_unlock_list();
+end:
+ return ret;
+}
+
+static int action_executor_list_handler(struct action_executor *executor,
+ const struct action_work_item *work_item,
+ struct action_work_subitem *item)
+{
+ ERR("Execution of a list action by the action executor should never occur");
+ abort();
+}
+
+static int action_executor_generic_handler(struct action_executor *executor,
+ const struct action_work_item *work_item,
+ struct action_work_subitem *item)
+{
+ int ret;
+ struct lttng_action *action = item->action;
+ const enum lttng_action_type action_type = lttng_action_get_type(action);
+
+ LTTNG_ASSERT(action_type != LTTNG_ACTION_TYPE_UNKNOWN);
+
+ lttng_action_increase_execution_request_count(action);
+ if (!lttng_action_should_execute(action)) {
+ DBG("Policy prevented execution of action `%s` of trigger `%s` action work item %" PRIu64,
+ get_action_name(action),
+ get_trigger_name(work_item->trigger),
+ work_item->id);
+ ret = 0;
+ goto end;
+ }
+
+ lttng_action_increase_execution_count(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);
+ ret = action_executors[action_type](executor, work_item, item);
+end:
+ return ret;
+}
+
+static int action_work_item_execute(struct action_executor *executor,
+ struct action_work_item *work_item)
+{
+ int ret;
+ size_t count, i;
+
+ DBG("Starting execution of action work item %" PRIu64 " of trigger `%s`",
+ work_item->id, get_trigger_name(work_item->trigger));
+
+ count = lttng_dynamic_array_get_count(&work_item->subitems);
+ for (i = 0; i < count; i++) {
+ struct action_work_subitem *item;
+
+ item = (action_work_subitem *) lttng_dynamic_array_get_element(&work_item->subitems, i);
+ ret = action_executor_generic_handler(
+ executor, work_item, item);
+ if (ret) {
+ goto end;
+ }
+ }
+end:
+ 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);
+ lttng_evaluation_destroy(work_item->evaluation);
+ notification_client_list_put(work_item->client_list);
+ lttng_dynamic_array_reset(&work_item->subitems);
+ free(work_item);
+}
+
+static void *action_executor_thread(void *_data)
+{
+ struct action_executor *executor = (action_executor *) _data;
+
+ LTTNG_ASSERT(executor);
+
+ health_register(the_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 = 0;
+ 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 list with 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);
+
+ /* Execute item only if a trigger is registered. */
+ lttng_trigger_lock(work_item->trigger);
+ if (!lttng_trigger_is_registered(work_item->trigger)) {
+ const char *trigger_name = NULL;
+ uid_t trigger_owner_uid;
+ enum lttng_trigger_status trigger_status;
+
+ trigger_name = get_trigger_name(work_item->trigger);
+
+ trigger_status = lttng_trigger_get_owner_uid(
+ work_item->trigger, &trigger_owner_uid);
+ LTTNG_ASSERT(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+ DBG("Work item skipped since the associated trigger is no longer registered: work item id = %" PRIu64 ", trigger name = '%s', trigger owner uid = %d",
+ work_item->id, trigger_name,
+ (int) trigger_owner_uid);
+ ret = 0;
+ goto skip_execute;
+ }
+
+ ret = action_work_item_execute(executor, work_item);
+
+ skip_execute:
+ lttng_trigger_unlock(work_item->trigger);
+ action_work_item_destroy(work_item);
+ if (ret) {
+ /* Fatal error. */
+ break;
+ }
+
+ health_code_update();
+ pthread_mutex_lock(&executor->work.lock);
+ }
+
+ if (executor->should_quit) {
+ pthread_mutex_unlock(&executor->work.lock);
+ }
+ DBG("Left work execution loop");
+
+ health_code_update();
+
+ rcu_thread_offline();
+ rcu_unregister_thread();
+ health_unregister(the_health_sessiond);
+
+ return NULL;
+}
+
+static bool shutdown_action_executor_thread(void *_data)
+{
+ struct action_executor *executor = (action_executor *) _data;
+
+ pthread_mutex_lock(&executor->work.lock);
+ executor->should_quit = true;
+ pthread_cond_signal(&executor->work.cond);
+ pthread_mutex_unlock(&executor->work.lock);
+ return true;
+}
+
+static void clean_up_action_executor_thread(void *_data)
+{
+ struct action_executor *executor = (action_executor *) _data;
+
+ LTTNG_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 = (action_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_trigger(
+ struct action_executor *executor,
+ struct lttng_trigger *trigger,
+ struct lttng_evaluation *evaluation,
+ const struct lttng_credentials *object_creds,
+ struct notification_client_list *client_list)
+{
+ int ret;
+ 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;
+
+ LTTNG_ASSERT(trigger);
+
+ 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 (overflow): trigger name = `%s`, work item id = %" PRIu64,
+ get_trigger_name(trigger), work_item_id);
+ executor_status = ACTION_EXECUTOR_STATUS_OVERFLOW;
+ goto error_unlock;
+ }
+
+ work_item = (action_work_item *) zmalloc(sizeof(*work_item));
+ if (!work_item) {
+ PERROR("Failed to allocate action executor work item: trigger name = '%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);
+
+ LTTNG_ASSERT(reference_acquired);
+ }
+
+ work_item->id = work_item_id;
+ work_item->trigger = trigger;
+
+ /* Ownership transferred to the work item. */
+ work_item->evaluation = evaluation;
+ evaluation = NULL;
+
+ work_item->client_list = client_list;
+ work_item->object_creds.is_set = !!object_creds;
+ if (object_creds) {
+ work_item->object_creds.value = *object_creds;
+ }
+
+ CDS_INIT_LIST_HEAD(&work_item->list_node);
+
+ /* Build the array of action work subitems for the passed trigger. */
+ lttng_dynamic_array_init(&work_item->subitems,
+ sizeof(struct action_work_subitem),
+ action_work_subitem_destructor);
+
+ ret = populate_subitem_array_from_trigger(
+ trigger, &work_item->subitems);
+ if (ret) {
+ ERR("Failed to populate work item sub items on behalf of trigger: trigger name = `%s`",
+ get_trigger_name(trigger));
+ executor_status = ACTION_EXECUTOR_STATUS_ERROR;
+ goto error_unlock;
+ }
+
+ cds_list_add_tail(&work_item->list_node, &executor->work.list);
+ executor->work.pending_count++;
+ DBG("Enqueued action for trigger: trigger name = `%s`, work item id = %" PRIu64,
+ get_trigger_name(trigger), work_item_id);
+ signal = true;
+
+error_unlock:
+ if (signal) {
+ pthread_cond_signal(&executor->work.cond);
+ }
+
+ pthread_mutex_unlock(&executor->work.lock);
+ lttng_evaluation_destroy(evaluation);
+ return executor_status;
+}
+
+static int add_action_to_subitem_array(struct lttng_action *action,
+ struct lttng_dynamic_array *subitems)
+{
+ int ret = 0;
+ enum lttng_action_type type = lttng_action_get_type(action);
+ const char *session_name = NULL;
+ enum lttng_action_status status;
+ struct action_work_subitem subitem = {
+ .action = NULL,
+ .context = {
+ .session_id = LTTNG_OPTIONAL_INIT_UNSET,
+ },
+ };
+
+ LTTNG_ASSERT(action);
+ LTTNG_ASSERT(subitems);
+
+ if (type == LTTNG_ACTION_TYPE_LIST) {
+ unsigned int count, i;
+
+ status = lttng_action_list_get_count(action, &count);
+ LTTNG_ASSERT(status == LTTNG_ACTION_STATUS_OK);
+
+ for (i = 0; i < count; i++) {
+ struct lttng_action *inner_action = NULL;
+
+ inner_action = lttng_action_list_borrow_mutable_at_index(
+ action, i);
+ LTTNG_ASSERT(inner_action);
+ ret = add_action_to_subitem_array(
+ inner_action, subitems);
+ if (ret) {
+ goto end;
+ }
+ }
+
+ /*
+ * Go directly to the end since there is no need to add the
+ * list action by itself to the subitems array.
+ */
+ goto end;
+ }
+
+ /* Gather execution context. */
+ switch (type) {
+ case LTTNG_ACTION_TYPE_NOTIFY:
+ break;
+ case LTTNG_ACTION_TYPE_START_SESSION:
+ status = lttng_action_start_session_get_session_name(
+ action, &session_name);
+ LTTNG_ASSERT(status == LTTNG_ACTION_STATUS_OK);
+ break;
+ case LTTNG_ACTION_TYPE_STOP_SESSION:
+ status = lttng_action_stop_session_get_session_name(
+ action, &session_name);
+ LTTNG_ASSERT(status == LTTNG_ACTION_STATUS_OK);
+ break;
+ case LTTNG_ACTION_TYPE_ROTATE_SESSION:
+ status = lttng_action_rotate_session_get_session_name(
+ action, &session_name);
+ LTTNG_ASSERT(status == LTTNG_ACTION_STATUS_OK);
+ break;
+ case LTTNG_ACTION_TYPE_SNAPSHOT_SESSION:
+ status = lttng_action_snapshot_session_get_session_name(
+ action, &session_name);
+ LTTNG_ASSERT(status == LTTNG_ACTION_STATUS_OK);
+ break;
+ case LTTNG_ACTION_TYPE_LIST:
+ case LTTNG_ACTION_TYPE_UNKNOWN:
+ /* Fallthrough */
+ default:
+ abort();
+ break;
+ }
+
+ /*
+ * Fetch the session execution context info as needed.
+ * Note that we could decide to not add an action for which we know the
+ * execution will not happen (i.e no session exists for that name). For
+ * now we leave the decision to skip to the action executor for sake of
+ * simplicity and consistency.
+ */
+ if (session_name != NULL) {
+ uint64_t session_id;
+
+ /*
+ * Instantaneous sampling of the session id if present.
+ *
+ * This method is preferred over `sessiond_find_by_name` then
+ * fetching the session'd id since `sessiond_find_by_name`
+ * requires the session list lock to be taken.
+ *
+ * Taking the session list lock can lead to a deadlock
+ * between the action executor and the notification thread
+ * (caller of add_action_to_subitem_array). It is okay if the
+ * session state changes between the enqueuing time and the
+ * execution time. The execution context is validated at
+ * execution time.
+ */
+ if (sample_session_id_by_name(session_name, &session_id)) {
+ LTTNG_OPTIONAL_SET(&subitem.context.session_id,
+ session_id);
+ }
+ }
+
+ /* Get a reference to the action. */
+ lttng_action_get(action);
+ subitem.action = action;
+
+ ret = lttng_dynamic_array_add_element(subitems, &subitem);
+ if (ret) {
+ ERR("Failed to add work subitem to the subitem array");
+ lttng_action_put(action);
+ ret = -1;
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+static int populate_subitem_array_from_trigger(struct lttng_trigger *trigger,
+ struct lttng_dynamic_array *subitems)
+{
+ struct lttng_action *action;
+
+ action = lttng_trigger_get_action(trigger);
+ LTTNG_ASSERT(action);
+
+ return add_action_to_subitem_array(action, subitems);
+}
projects / lttng-tools.git / blobdiff