trigger: generate and add tracer token on registration
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-events.c
index e01a00538ba8d2f04c389086860ebfd933798e9f..398ddc3896c39c7a94a67778a986057dceeae93c 100644 (file)
@@ -27,6 +27,7 @@
 #include <lttng/condition/session-consumed-size-internal.h>
 #include <lttng/condition/session-rotation-internal.h>
 #include <lttng/notification/channel-internal.h>
+#include <lttng/trigger/trigger-internal.h>
 
 #include <time.h>
 #include <unistd.h>
@@ -110,6 +111,7 @@ struct lttng_session_trigger_list {
 struct lttng_trigger_ht_element {
        struct lttng_trigger *trigger;
        struct cds_lfht_node node;
+       struct cds_lfht_node node_by_name_uid;
        /* call_rcu delayed reclaim. */
        struct rcu_head rcu_node;
 };
@@ -187,6 +189,9 @@ int client_handle_transmission_status(
                enum client_transmission_status transmission_status,
                struct notification_thread_state *state);
 
+static
+void free_lttng_trigger_ht_element_rcu(struct rcu_head *node);
+
 static
 int match_client_socket(struct cds_lfht_node *node, const void *key)
 {
@@ -261,18 +266,15 @@ int match_channel_info(struct cds_lfht_node *node, const void *key)
 }
 
 static
-int match_condition(struct cds_lfht_node *node, const void *key)
+int match_trigger(struct cds_lfht_node *node, const void *key)
 {
-       struct lttng_condition *condition_key = (struct lttng_condition *) key;
-       struct lttng_trigger_ht_element *trigger;
-       struct lttng_condition *condition;
+       struct lttng_trigger *trigger_key = (struct lttng_trigger *) key;
+       struct lttng_trigger_ht_element *trigger_ht_element;
 
-       trigger = caa_container_of(node, struct lttng_trigger_ht_element,
+       trigger_ht_element = caa_container_of(node, struct lttng_trigger_ht_element,
                        node);
-       condition = lttng_trigger_get_condition(trigger->trigger);
-       assert(condition);
 
-       return !!lttng_condition_is_equal(condition_key, condition);
+       return !!lttng_trigger_is_equal(trigger_key, trigger_ht_element->trigger);
 }
 
 static
@@ -301,6 +303,71 @@ int match_session(struct cds_lfht_node *node, const void *key)
        return !strcmp(session_info->name, name);
 }
 
+/*
+ * Match trigger based on name and credentials only.
+ * Name duplication is NOT allowed for the same uid.
+ */
+static
+int match_trigger_by_name_uid(struct cds_lfht_node *node,
+               const void *key)
+{
+       bool match = false;
+       const char *name;
+       const char *key_name;
+       enum lttng_trigger_status status;
+       const struct lttng_credentials *key_creds;
+       const struct lttng_credentials *node_creds;
+       const struct lttng_trigger *trigger_key =
+                       (const struct lttng_trigger *) key;
+       const struct lttng_trigger_ht_element *trigger_ht_element =
+                       caa_container_of(node,
+                               struct lttng_trigger_ht_element,
+                               node_by_name_uid);
+
+       status = lttng_trigger_get_name(trigger_ht_element->trigger, &name);
+       assert(status == LTTNG_TRIGGER_STATUS_OK);
+
+       status = lttng_trigger_get_name(trigger_key, &key_name);
+       assert(status == LTTNG_TRIGGER_STATUS_OK);
+
+       /* Compare the names. */
+       if (strcmp(name, key_name) != 0) {
+               goto end;
+       }
+
+       /* Compare the owners' UIDs. */
+       key_creds = lttng_trigger_get_credentials(trigger_key);
+       node_creds = lttng_trigger_get_credentials(trigger_ht_element->trigger);
+
+       match = lttng_credentials_is_equal_uid(key_creds, node_creds);
+
+end:
+       return match;
+}
+
+/*
+ * Hash trigger based on name and credentials only.
+ */
+static
+unsigned long hash_trigger_by_name_uid(const struct lttng_trigger *trigger)
+{
+       unsigned long hash = 0;
+       const struct lttng_credentials *trigger_creds;
+       const char *trigger_name;
+       enum lttng_trigger_status status;
+
+       status = lttng_trigger_get_name(trigger, &trigger_name);
+       if (status == LTTNG_TRIGGER_STATUS_OK) {
+               hash = hash_key_str(trigger_name, lttng_ht_seed);
+       }
+
+       trigger_creds = lttng_trigger_get_credentials(trigger);
+       hash ^= hash_key_ulong((void *) (unsigned long) LTTNG_OPTIONAL_GET(trigger_creds->uid),
+                       lttng_ht_seed);
+
+       return hash;
+}
+
 static
 unsigned long lttng_condition_buffer_usage_hash(
        const struct lttng_condition *_condition)
@@ -1807,8 +1874,8 @@ int handle_notification_thread_command_session_rotation(
        struct lttng_trigger_list_element *trigger_list_element;
        struct session_info *session_info;
        const struct lttng_credentials session_creds = {
-               .uid = session_uid,
-               .gid = session_gid,
+               .uid = LTTNG_OPTIONAL_INIT_VALUE(session_uid),
+               .gid = LTTNG_OPTIONAL_INIT_VALUE(session_gid),
        };
 
        rcu_read_lock();
@@ -2085,6 +2152,50 @@ end:
        return is_notify;
 }
 
+static bool trigger_name_taken(struct notification_thread_state *state,
+               const struct lttng_trigger *trigger)
+{
+       struct cds_lfht_iter iter;
+
+       /*
+        * No duplicata is allowed in the triggers_by_name_uid_ht.
+        * The match is done against the trigger name and uid.
+        */
+       cds_lfht_lookup(state->triggers_by_name_uid_ht,
+                       hash_trigger_by_name_uid(trigger),
+                       match_trigger_by_name_uid,
+                       trigger,
+                       &iter);
+       return !!cds_lfht_iter_get_node(&iter);
+}
+
+static
+enum lttng_error_code generate_trigger_name(
+               struct notification_thread_state *state,
+               struct lttng_trigger *trigger, const char **name)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+       bool taken = false;
+       enum lttng_trigger_status status;
+
+       do {
+               const int ret = lttng_trigger_generate_name(trigger,
+                               state->trigger_id.name_offset++);
+               if (ret) {
+                       /* The only reason this can fail right now. */
+                       ret_code = LTTNG_ERR_NOMEM;
+                       break;
+               }
+
+               status = lttng_trigger_get_name(trigger, name);
+               assert(status == LTTNG_TRIGGER_STATUS_OK);
+
+               taken = trigger_name_taken(state, trigger);
+       } while (taken || state->trigger_id.name_offset == UINT64_MAX);
+
+       return ret_code;
+}
+
 /*
  * FIXME A client's credentials are not checked when registering a trigger.
  *
@@ -2114,13 +2225,39 @@ int handle_notification_thread_command_register_trigger(
        struct notification_client_list_element *client_list_element;
        struct cds_lfht_node *node;
        struct cds_lfht_iter iter;
+       const char* trigger_name;
        bool free_trigger = true;
        struct lttng_evaluation *evaluation = NULL;
        struct lttng_credentials object_creds;
+       uid_t object_uid;
+       gid_t object_gid;
        enum action_executor_status executor_status;
+       const uint64_t trigger_tracer_token =
+                       state->trigger_id.next_tracer_token++;
 
        rcu_read_lock();
 
+       /* Set the trigger's tracer token. */
+       lttng_trigger_set_tracer_token(trigger, trigger_tracer_token);
+
+       if (lttng_trigger_get_name(trigger, &trigger_name) ==
+                       LTTNG_TRIGGER_STATUS_UNSET) {
+               const enum lttng_error_code ret_code = generate_trigger_name(
+                               state, trigger, &trigger_name);
+
+               if (ret_code != LTTNG_OK) {
+                       /* Fatal error. */
+                       ret = -1;
+                       *cmd_result = ret_code;
+                       goto error;
+               }
+       } else if (trigger_name_taken(state, trigger)) {
+               /* Not a fatal error. */
+               *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
+               ret = 0;
+               goto error;
+       }
+
        condition = lttng_trigger_get_condition(trigger);
        assert(condition);
 
@@ -2143,12 +2280,13 @@ int handle_notification_thread_command_register_trigger(
 
        /* Add trigger to the trigger_ht. */
        cds_lfht_node_init(&trigger_ht_element->node);
+       cds_lfht_node_init(&trigger_ht_element->node_by_name_uid);
        trigger_ht_element->trigger = trigger;
 
        node = cds_lfht_add_unique(state->triggers_ht,
                        lttng_condition_hash(condition),
-                       match_condition,
-                       condition,
+                       match_trigger,
+                       trigger,
                        &trigger_ht_element->node);
        if (node != &trigger_ht_element->node) {
                /* Not a fatal error, simply report it to the client. */
@@ -2156,6 +2294,18 @@ int handle_notification_thread_command_register_trigger(
                goto error_free_ht_element;
        }
 
+       node = cds_lfht_add_unique(state->triggers_by_name_uid_ht,
+                       hash_trigger_by_name_uid(trigger),
+                       match_trigger_by_name_uid,
+                       trigger,
+                       &trigger_ht_element->node_by_name_uid);
+       if (node != &trigger_ht_element->node_by_name_uid) {
+               /* Not a fatal error, simply report it to the client. */
+               cds_lfht_del(state->triggers_ht, &trigger_ht_element->node);
+               *cmd_result = LTTNG_ERR_TRIGGER_EXISTS;
+               goto error_free_ht_element;
+       }
+
        /*
         * Ownership of the trigger and of its wrapper was transfered to
         * the triggers_ht.
@@ -2260,21 +2410,21 @@ int handle_notification_thread_command_register_trigger(
        switch (get_condition_binding_object(condition)) {
        case LTTNG_OBJECT_TYPE_SESSION:
                ret = evaluate_session_condition_for_client(condition, state,
-                               &evaluation, &object_creds.uid,
-                               &object_creds.gid);
+                               &evaluation, &object_uid,
+                               &object_gid);
                break;
        case LTTNG_OBJECT_TYPE_CHANNEL:
                ret = evaluate_channel_condition_for_client(condition, state,
-                               &evaluation, &object_creds.uid,
-                               &object_creds.gid);
+                               &evaluation, &object_uid,
+                               &object_gid);
                break;
        case LTTNG_OBJECT_TYPE_NONE:
                ret = 0;
-               goto error_put_client_list;
+               break;
        case LTTNG_OBJECT_TYPE_UNKNOWN:
        default:
                ret = -1;
-               goto error_put_client_list;
+               break;
        }
 
        if (ret) {
@@ -2282,12 +2432,15 @@ int handle_notification_thread_command_register_trigger(
                goto error_put_client_list;
        }
 
+       LTTNG_OPTIONAL_SET(&object_creds.uid, object_uid);
+       LTTNG_OPTIONAL_SET(&object_creds.gid, object_gid);
+
        DBG("Newly registered trigger's condition evaluated to %s",
                        evaluation ? "true" : "false");
        if (!evaluation) {
                /* Evaluation yielded nothing. Normal exit. */
                ret = 0;
-               goto error_put_client_list;
+               goto end;
        }
 
        /*
@@ -2318,18 +2471,26 @@ int handle_notification_thread_command_register_trigger(
                 */
                WARN("No space left when enqueuing action associated to newly registered trigger");
                ret = 0;
-               goto error_put_client_list;
+               goto end;
        default:
                abort();
        }
 
+end:
        *cmd_result = LTTNG_OK;
+       DBG("Registered trigger: name = `%s`, tracer token = %" PRIu64,
+                       trigger_name, trigger_tracer_token);
 
 error_put_client_list:
        notification_client_list_put(client_list);
 
 error_free_ht_element:
-       free(trigger_ht_element);
+       if (trigger_ht_element) {
+               /* Delayed removal due to RCU constraint on delete. */
+               call_rcu(&trigger_ht_element->rcu_node,
+                               free_lttng_trigger_ht_element_rcu);
+       }
+
 error:
        if (free_trigger) {
                lttng_trigger_destroy(trigger);
@@ -2364,8 +2525,8 @@ int handle_notification_thread_command_unregister_trigger(
 
        cds_lfht_lookup(state->triggers_ht,
                        lttng_condition_hash(condition),
-                       match_condition,
-                       condition,
+                       match_trigger,
+                       trigger,
                        &iter);
        triggers_ht_node = cds_lfht_iter_get_node(&iter);
        if (!triggers_ht_node) {
@@ -2414,6 +2575,7 @@ int handle_notification_thread_command_unregister_trigger(
        /* Remove trigger from triggers_ht. */
        trigger_ht_element = caa_container_of(triggers_ht_node,
                        struct lttng_trigger_ht_element, node);
+       cds_lfht_del(state->triggers_by_name_uid_ht, &trigger_ht_element->node_by_name_uid);
        cds_lfht_del(state->triggers_ht, triggers_ht_node);
 
        /* Release the ownership of the trigger. */
@@ -3582,11 +3744,15 @@ int send_evaluation_to_clients(const struct lttng_trigger *trigger,
                struct notification_thread_state *state,
                uid_t object_uid, gid_t object_gid)
 {
+       const struct lttng_credentials creds = {
+               .uid = LTTNG_OPTIONAL_INIT_VALUE(object_uid),
+               .gid = LTTNG_OPTIONAL_INIT_VALUE(object_gid),
+       };
+
        return notification_client_list_send_evaluation(client_list,
                        lttng_trigger_get_const_condition(trigger), evaluation,
                        lttng_trigger_get_credentials(trigger),
-                       &(struct lttng_credentials){
-                                       .uid = object_uid, .gid = object_gid},
+                       &creds,
                        client_handle_transmission_status_wrapper, state);
 }
 
@@ -3693,8 +3859,8 @@ int notification_client_list_send_evaluation(
                }
 
                if (source_object_creds) {
-                       if (client->uid != source_object_creds->uid &&
-                                       client->gid != source_object_creds->gid &&
+                       if (client->uid != lttng_credentials_get_uid(source_object_creds) &&
+                                       client->gid != lttng_credentials_get_gid(source_object_creds) &&
                                        client->uid != 0) {
                                /*
                                 * Client is not allowed to monitor this
@@ -3705,7 +3871,7 @@ int notification_client_list_send_evaluation(
                        }
                }
 
-               if (client->uid != trigger_creds->uid && client->gid != trigger_creds->gid) {
+               if (client->uid != lttng_credentials_get_uid(trigger_creds) && client->gid != lttng_credentials_get_gid(trigger_creds)) {
                        DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this trigger");
                        goto skip_client;
                }
@@ -3894,8 +4060,8 @@ int handle_notification_thread_channel_sample(
        }
 
        channel_creds = (typeof(channel_creds)) {
-               .uid = channel_info->session_info->uid,
-               .gid = channel_info->session_info->gid,
+               .uid = LTTNG_OPTIONAL_INIT_VALUE(channel_info->session_info->uid),
+               .gid = LTTNG_OPTIONAL_INIT_VALUE(channel_info->session_info->gid),
        };
 
        trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
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