sessiond: synchronize event notifiers for UST tracers and the kernel tracer

Synchronize event notifiers when registering or unregistering a trigger
which has a condition that implies the use of an event notifier.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Id2cb2a93c0c6be9f44f9dcd07b9803acbcb6b3c3
Depends-on: lttng-ust: I5a800fc92e588c2a6a0e26282b0ad5f31c044479

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 061629d11424866cbbadeb173149e2d699a60fcc..5c8efb40ee2c658e4959716836de214dc4bdc5a2 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -29,6 +29,11 @@
 #include <lttng/location-internal.h>
 #include <lttng/trigger/trigger-internal.h>
 #include <lttng/condition/condition.h>
+#include <lttng/condition/condition-internal.h>
+#include <lttng/condition/event-rule.h>
+#include <lttng/condition/event-rule-internal.h>
+#include <lttng/event-rule/event-rule.h>
+#include <lttng/event-rule/event-rule-internal.h>
 #include <lttng/action/action.h>
 #include <lttng/channel.h>
 #include <lttng/channel-internal.h>
@@ -4288,12 +4293,44 @@ end:
        return ret;
 }
 
-int cmd_register_trigger(const struct lttng_credentials *cmd_creds,
+static enum lttng_error_code trigger_modifies_event_notifier(
+               const struct lttng_trigger *trigger, bool *adds_event_notifier)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+       const struct lttng_condition *condition = NULL;
+
+       condition = lttng_trigger_get_const_condition(trigger);
+       if (!condition) {
+               ret_code = LTTNG_ERR_INVALID_TRIGGER;
+               goto end;
+       }
+
+       *adds_event_notifier = lttng_condition_get_type(condition) ==
+                       LTTNG_CONDITION_TYPE_EVENT_RULE_HIT;
+end:
+       return ret_code;
+}
+
+enum lttng_error_code cmd_register_trigger(const struct lttng_credentials *cmd_creds,
                struct lttng_trigger *trigger,
                struct notification_thread_handle *notification_thread,
                struct lttng_trigger **return_trigger)
 {
-       int ret;
+       enum lttng_error_code ret_code;
+       bool must_update_event_notifier;
+       const char *trigger_name;
+       uid_t trigger_owner;
+       enum lttng_trigger_status trigger_status;
+
+       trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+       assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+       trigger_status = lttng_trigger_get_owner_uid(
+               trigger, &trigger_owner);
+       assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+       DBG("Running register trigger command: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+                       trigger_name, (int) trigger_owner,
+                       (int) lttng_credentials_get_uid(cmd_creds));
 
        /*
         * Validate the trigger credentials against the command credentials.
@@ -4304,8 +4341,10 @@ int cmd_register_trigger(const struct lttng_credentials *cmd_creds,
                        lttng_trigger_get_credentials(trigger),
                        cmd_creds)) {
                if (lttng_credentials_get_uid(cmd_creds) != 0) {
-                       ERR("Trigger credentials do not match the command credentials");
-                       ret = LTTNG_ERR_INVALID_TRIGGER;
+                       ERR("Trigger credentials do not match the command credentials: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+                                       trigger_name, (int) trigger_owner,
+                                       (int) lttng_credentials_get_uid(cmd_creds));
+                       ret_code = LTTNG_ERR_INVALID_TRIGGER;
                        goto end;
                }
        }
@@ -4314,8 +4353,10 @@ int cmd_register_trigger(const struct lttng_credentials *cmd_creds,
         * The bytecode generation also serves as a validation step for the
         * bytecode expressions.
         */
-       ret = lttng_trigger_generate_bytecode(trigger, cmd_creds);
-       if (ret != LTTNG_OK) {
+       ret_code = lttng_trigger_generate_bytecode(trigger, cmd_creds);
+       if (ret_code != LTTNG_OK) {
+               ERR("Failed to generate bytecode of trigger: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
                goto end;
        }
 
@@ -4329,12 +4370,51 @@ int cmd_register_trigger(const struct lttng_credentials *cmd_creds,
         * it is safe to use without any locking as its properties are
         * immutable.
         */
-       ret = notification_thread_command_register_trigger(notification_thread,
+       ret_code = notification_thread_command_register_trigger(notification_thread,
                        trigger);
-       if (ret != LTTNG_OK) {
+       if (ret_code != LTTNG_OK) {
+               ERR("Failed to register trigger to notification thread: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
+               goto end_notification_thread;
+       }
+
+       ret_code = trigger_modifies_event_notifier(trigger, &must_update_event_notifier);
+       if (ret_code != LTTNG_OK) {
+               ERR("Failed to determine if event modifies event notifiers: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
                goto end_notification_thread;
        }
 
+       /*
+        * Synchronize tracers if the trigger adds an event notifier.
+        */
+       if (must_update_event_notifier) {
+               if (lttng_trigger_get_underlying_domain_type_restriction(
+                                   trigger) == LTTNG_DOMAIN_KERNEL) {
+
+                       ret_code = kernel_register_event_notifier(
+                                       trigger, cmd_creds);
+                       if (ret_code != LTTNG_OK) {
+                               const enum lttng_error_code notif_thread_unregister_ret =
+                                               notification_thread_command_unregister_trigger(
+                                                               notification_thread,
+                                                               trigger);
+
+                               if (notif_thread_unregister_ret != LTTNG_OK) {
+                                       /* Return the original error code. */
+                                       ERR("Failed to unregister trigger from notification thread during error recovery: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                                                       trigger_name,
+                                                       (int) trigger_owner,
+                                                       ret_code);
+                               }
+
+                               goto end;
+                       }
+               } else {
+                       ust_app_global_update_all_event_notifier_rules();
+               }
+       }
+
        /*
         * Return an updated trigger to the client.
         *
@@ -4349,14 +4429,28 @@ end_notification_thread:
        /* Ownership of trigger was transferred. */
        trigger = NULL;
 end:
-       return ret;
+       return ret_code;
 }
 
-int cmd_unregister_trigger(const struct lttng_credentials *cmd_creds,
+enum lttng_error_code cmd_unregister_trigger(const struct lttng_credentials *cmd_creds,
                const struct lttng_trigger *trigger,
                struct notification_thread_handle *notification_thread)
 {
-       int ret;
+       enum lttng_error_code ret_code;
+       bool must_update_event_notifier;
+       const char *trigger_name;
+       uid_t trigger_owner;
+       enum lttng_trigger_status trigger_status;
+
+       trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
+       assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+       trigger_status = lttng_trigger_get_owner_uid(
+               trigger, &trigger_owner);
+       assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+       DBG("Running unregister trigger command: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+                       trigger_name, (int) trigger_owner,
+                       (int) lttng_credentials_get_uid(cmd_creds));
 
        /*
         * Validate the trigger credentials against the command credentials.
@@ -4367,16 +4461,44 @@ int cmd_unregister_trigger(const struct lttng_credentials *cmd_creds,
                        lttng_trigger_get_credentials(trigger),
                        cmd_creds)) {
                if (lttng_credentials_get_uid(cmd_creds) != 0) {
-                       ERR("Trigger credentials do not match the command credentials");
-                       ret = LTTNG_ERR_INVALID_TRIGGER;
+                       ERR("Trigger credentials do not match the command credentials: trigger name = '%s', trigger owner uid = %d, command creds uid = %d",
+                                       trigger_name, (int) trigger_owner,
+                                       (int) lttng_credentials_get_uid(cmd_creds));
+                       ret_code = LTTNG_ERR_INVALID_TRIGGER;
                        goto end;
                }
        }
 
-       ret = notification_thread_command_unregister_trigger(notification_thread,
-                       trigger);
+       ret_code = trigger_modifies_event_notifier(trigger, &must_update_event_notifier);
+       if (ret_code != LTTNG_OK) {
+               ERR("Failed to determine if event modifies event notifiers: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
+               goto end;
+       }
+
+       ret_code = notification_thread_command_unregister_trigger(notification_thread,
+                                                                 trigger);
+       if (ret_code != LTTNG_OK) {
+               ERR("Failed to unregister trigger from notification thread: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
+       }
+
+       /*
+        * Synchronize tracers if the trigger removes an event notifier.
+        */
+       if (must_update_event_notifier) {
+               if (lttng_trigger_get_underlying_domain_type_restriction(
+                                   trigger) == LTTNG_DOMAIN_KERNEL) {
+
+                       ret_code = kernel_unregister_event_notifier(
+                                       trigger);
+               } else {
+                       ust_app_global_update_all_event_notifier_rules();
+               }
+       }
+
 end:
-       return ret;
+       return ret_code;
 }
 
 int cmd_list_triggers(struct command_ctx *cmd_ctx,

diff --git a/src/bin/lttng-sessiond/cmd.h b/src/bin/lttng-sessiond/cmd.h
index a162a9a07e26cfbbda9a1dd7b1768825cefeceb3..e434d50d6253c9d4d79324c73d178dffa90260fe 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.h
+++ b/src/bin/lttng-sessiond/cmd.h
@@ -141,11 +141,13 @@ int cmd_set_session_shm_path(struct ltt_session *session,
 int cmd_regenerate_metadata(struct ltt_session *session);
 int cmd_regenerate_statedump(struct ltt_session *session);
 
-int cmd_register_trigger(const struct lttng_credentials *cmd_creds,
+enum lttng_error_code cmd_register_trigger(
+               const struct lttng_credentials *cmd_creds,
                struct lttng_trigger *trigger,
                struct notification_thread_handle *notification_thread_handle,
                struct lttng_trigger **return_trigger);
-int cmd_unregister_trigger(const struct lttng_credentials *cmd_creds,
+enum lttng_error_code cmd_unregister_trigger(
+               const struct lttng_credentials *cmd_creds,
                const struct lttng_trigger *trigger,
                struct notification_thread_handle *notification_thread_handle);
 

diff --git a/src/bin/lttng-sessiond/dispatch.c b/src/bin/lttng-sessiond/dispatch.c
index 52d253d47d3578923d5fbf69c1ce52b438ee5330..d33a3cba8fac0d231aabd527400b83adc7645d6f 100644 (file)
--- a/src/bin/lttng-sessiond/dispatch.c
+++ b/src/bin/lttng-sessiond/dispatch.c
@@ -36,6 +36,7 @@ static void update_ust_app(int app_sock)
 {
        struct ltt_session *sess, *stmp;
        const struct ltt_session_list *session_list = session_get_list();
+       struct ust_app *app;
 
        /* Consumer is in an ERROR state. Stop any application update. */
        if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) {
@@ -43,10 +44,25 @@ static void update_ust_app(int app_sock)
                return;
        }
 
+       rcu_read_lock();
+       assert(app_sock >= 0);
+       app = ust_app_find_by_sock(app_sock);
+       if (app == NULL) {
+               /*
+                * Application can be unregistered before so
+                * this is possible hence simply stopping the
+                * update.
+                */
+               DBG3("UST app update failed to find app sock %d",
+                       app_sock);
+               goto unlock_rcu;
+       }
+
+       /* Update all event notifiers for the app. */
+       ust_app_global_update_event_notifier_rules(app);
+
        /* For all tracing session(s) */
        cds_list_for_each_entry_safe(sess, stmp, &session_list->head, list) {
-               struct ust_app *app;
-
                if (!session_get(sess)) {
                        continue;
                }
@@ -55,26 +71,14 @@ static void update_ust_app(int app_sock)
                        goto unlock_session;
                }
 
-               rcu_read_lock();
-               assert(app_sock >= 0);
-               app = ust_app_find_by_sock(app_sock);
-               if (app == NULL) {
-                       /*
-                        * Application can be unregistered before so
-                        * this is possible hence simply stopping the
-                        * update.
-                        */
-                       DBG3("UST app update failed to find app sock %d",
-                               app_sock);
-                       goto unlock_rcu;
-               }
                ust_app_global_update(sess->ust_session, app);
-       unlock_rcu:
-               rcu_read_unlock();
        unlock_session:
                session_unlock(sess);
                session_put(sess);
        }
+
+unlock_rcu:
+       rcu_read_unlock();
 }
 
 /*