X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fnotification-thread-events.c;h=3f8cb4804ddd0800061f634afb3d6e92022e8103;hp=040ae5f28a355bd235e91ca4630887de823c6b9c;hb=0ab399e0bcf4e99492845f02e3e5b405155dea92;hpb=a9577b7628a85b064c3f249c3504bad989848b49 diff --git a/src/bin/lttng-sessiond/notification-thread-events.c b/src/bin/lttng-sessiond/notification-thread-events.c index 040ae5f28..3f8cb4804 100644 --- a/src/bin/lttng-sessiond/notification-thread-events.c +++ b/src/bin/lttng-sessiond/notification-thread-events.c @@ -1,18 +1,8 @@ /* - * Copyright (C) 2017 - Jérémie Galarneau + * Copyright (C) 2017 Jérémie Galarneau * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License, version 2 only, as - * published by the Free Software Foundation. + * SPDX-License-Identifier: GPL-2.0-only * - * This program is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for - * more details. - * - * You should have received a copy of the GNU General Public License along with - * this program; if not, write to the Free Software Foundation, Inc., 51 - * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #define _LGPL_SOURCE @@ -70,6 +60,8 @@ struct lttng_channel_trigger_list { struct cds_list_head list; /* Node in the channel_triggers_ht */ struct cds_lfht_node channel_triggers_ht_node; + /* call_rcu delayed reclaim. */ + struct rcu_head rcu_node; }; /* @@ -116,6 +108,8 @@ struct lttng_session_trigger_list { struct lttng_trigger_ht_element { struct lttng_trigger *trigger; struct cds_lfht_node node; + /* call_rcu delayed reclaim. */ + struct rcu_head rcu_node; }; struct lttng_condition_list_element { @@ -128,13 +122,41 @@ struct notification_client_list_element { struct cds_list_head node; }; +/* + * Thread safety of notification_client and notification_client_list. + * + * The notification thread (main thread) and the action executor + * interact through client lists. Hence, when the action executor + * thread looks-up the list of clients subscribed to a given + * condition, it will acquire a reference to the list and lock it + * while attempting to communicate with the various clients. + * + * It is not necessary to reference-count clients as they are guaranteed + * to be 'alive' if they are present in a list and that list is locked. Indeed, + * removing references to the client from those subscription lists is part of + * the work performed on destruction of a client. + * + * No provision for other access scenarios are taken into account; + * this is the bare minimum to make these accesses safe and the + * notification thread's state is _not_ "thread-safe" in any general + * sense. + */ struct notification_client_list { + pthread_mutex_t lock; + struct urcu_ref ref; const struct lttng_trigger *trigger; struct cds_list_head list; - struct cds_lfht_node notification_trigger_ht_node; + /* Weak reference to container. */ + struct cds_lfht *notification_trigger_clients_ht; + struct cds_lfht_node notification_trigger_clients_ht_node; + /* call_rcu delayed reclaim. */ + struct rcu_head rcu_node; }; struct notification_client { + /* Nests within the notification_client_list lock. */ + pthread_mutex_t lock; + notification_client_id id; int socket; /* Client protocol version. */ uint8_t major, minor; @@ -152,7 +174,16 @@ struct notification_client { */ struct cds_list_head condition_list; struct cds_lfht_node client_socket_ht_node; + struct cds_lfht_node client_id_ht_node; struct { + /* + * If a client's communication is inactive, it means that a + * fatal error has occurred (could be either a protocol error or + * the socket API returned a fatal error). No further + * communication should be attempted; the client is queued for + * clean-up. + */ + bool active; struct { /* * During the reception of a message, the reception @@ -198,6 +229,8 @@ struct notification_client { struct lttng_dynamic_buffer buffer; } outbound; } communication; + /* call_rcu delayed reclaim. */ + struct rcu_head rcu_node; }; struct channel_state_sample { @@ -206,6 +239,8 @@ struct channel_state_sample { uint64_t highest_usage; uint64_t lowest_usage; uint64_t channel_total_consumed; + /* call_rcu delayed reclaim. */ + struct rcu_head rcu_node; }; static unsigned long hash_channel_key(struct channel_key *key); @@ -262,16 +297,25 @@ int lttng_session_trigger_list_add(struct lttng_session_trigger_list *list, static -int match_client(struct cds_lfht_node *node, const void *key) +int match_client_socket(struct cds_lfht_node *node, const void *key) { /* This double-cast is intended to supress pointer-to-cast warning. */ - int socket = (int) (intptr_t) key; - struct notification_client *client; + const int socket = (int) (intptr_t) key; + const struct notification_client *client = caa_container_of(node, + struct notification_client, client_socket_ht_node); - client = caa_container_of(node, struct notification_client, - client_socket_ht_node); + return client->socket == socket; +} + +static +int match_client_id(struct cds_lfht_node *node, const void *key) +{ + /* This double-cast is intended to supress pointer-to-cast warning. */ + const notification_client_id id = *((notification_client_id *) key); + const struct notification_client *client = caa_container_of( + node, struct notification_client, client_id_ht_node); - return !!(client->socket == socket); + return client->id == id; } static @@ -350,7 +394,7 @@ int match_client_list_condition(struct cds_lfht_node *node, const void *key) assert(condition_key); client_list = caa_container_of(node, struct notification_client_list, - notification_trigger_ht_node); + notification_trigger_clients_ht_node); condition = lttng_trigger_get_const_condition(client_list->trigger); return !!lttng_condition_is_equal(condition_key, condition); @@ -475,6 +519,18 @@ unsigned long hash_channel_key(struct channel_key *key) return key_hash ^ domain_hash; } +static +unsigned long hash_client_socket(int socket) +{ + return hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed); +} + +static +unsigned long hash_client_id(notification_client_id id) +{ + return hash_key_u64(&id, lttng_ht_seed); +} + /* * Get the type of object to which a given condition applies. Bindings let * the notification system evaluate a trigger's condition when a given @@ -491,7 +547,7 @@ enum lttng_object_type get_condition_binding_object( case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW: case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH: case LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE: - return LTTNG_OBJECT_TYPE_CHANNEL; + return LTTNG_OBJECT_TYPE_CHANNEL; case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING: case LTTNG_CONDITION_TYPE_SESSION_ROTATION_COMPLETED: return LTTNG_OBJECT_TYPE_SESSION; @@ -500,6 +556,12 @@ enum lttng_object_type get_condition_binding_object( } } +static +void free_channel_info_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct channel_info, rcu_node)); +} + static void channel_info_destroy(struct channel_info *channel_info) { @@ -515,7 +577,13 @@ void channel_info_destroy(struct channel_info *channel_info) if (channel_info->name) { free(channel_info->name); } - free(channel_info); + call_rcu(&channel_info->rcu_node, free_channel_info_rcu); +} + +static +void free_session_info_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct session_info, rcu_node)); } /* Don't call directly, use the ref-counting mechanism. */ @@ -539,7 +607,7 @@ void session_info_destroy(void *_data) &session_info->sessions_ht_node); rcu_read_unlock(); free(session_info->name); - free(session_info); + call_rcu(&session_info->rcu_node, free_session_info_rcu); } static @@ -654,7 +722,90 @@ error: return NULL; } -/* RCU read lock must be held by the caller. */ +static +bool notification_client_list_get(struct notification_client_list *list) +{ + return urcu_ref_get_unless_zero(&list->ref); +} + +static +void free_notification_client_list_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct notification_client_list, + rcu_node)); +} + +static +void notification_client_list_release(struct urcu_ref *list_ref) +{ + struct notification_client_list *list = + container_of(list_ref, typeof(*list), ref); + struct notification_client_list_element *client_list_element, *tmp; + + if (list->notification_trigger_clients_ht) { + rcu_read_lock(); + cds_lfht_del(list->notification_trigger_clients_ht, + &list->notification_trigger_clients_ht_node); + rcu_read_unlock(); + list->notification_trigger_clients_ht = NULL; + } + cds_list_for_each_entry_safe(client_list_element, tmp, + &list->list, node) { + free(client_list_element); + } + pthread_mutex_destroy(&list->lock); + call_rcu(&list->rcu_node, free_notification_client_list_rcu); +} + +static +struct notification_client_list *notification_client_list_create( + const struct lttng_trigger *trigger) +{ + struct notification_client_list *client_list = + zmalloc(sizeof(*client_list)); + + if (!client_list) { + goto error; + } + pthread_mutex_init(&client_list->lock, NULL); + urcu_ref_init(&client_list->ref); + cds_lfht_node_init(&client_list->notification_trigger_clients_ht_node); + CDS_INIT_LIST_HEAD(&client_list->list); + client_list->trigger = trigger; +error: + return client_list; +} + +static +void publish_notification_client_list( + struct notification_thread_state *state, + struct notification_client_list *list) +{ + const struct lttng_condition *condition = + lttng_trigger_get_const_condition(list->trigger); + + assert(!list->notification_trigger_clients_ht); + + list->notification_trigger_clients_ht = + state->notification_trigger_clients_ht; + + rcu_read_lock(); + cds_lfht_add(state->notification_trigger_clients_ht, + lttng_condition_hash(condition), + &list->notification_trigger_clients_ht_node); + rcu_read_unlock(); +} + +static +void notification_client_list_put(struct notification_client_list *list) +{ + if (!list) { + return; + } + return urcu_ref_put(&list->ref, notification_client_list_release); +} + +/* Provides a reference to the returned list. */ static struct notification_client_list *get_client_list_from_condition( struct notification_thread_state *state, @@ -662,20 +813,25 @@ struct notification_client_list *get_client_list_from_condition( { struct cds_lfht_node *node; struct cds_lfht_iter iter; + struct notification_client_list *list = NULL; + rcu_read_lock(); cds_lfht_lookup(state->notification_trigger_clients_ht, lttng_condition_hash(condition), match_client_list_condition, condition, &iter); node = cds_lfht_iter_get_node(&iter); + if (node) { + list = container_of(node, struct notification_client_list, + notification_trigger_clients_ht_node); + list = notification_client_list_get(list) ? list : NULL; + } - return node ? caa_container_of(node, - struct notification_client_list, - notification_trigger_ht_node) : NULL; + rcu_read_unlock(); + return list; } -/* This function must be called with the RCU read lock held. */ static int evaluate_channel_condition_for_client( const struct lttng_condition *condition, @@ -691,6 +847,8 @@ int evaluate_channel_condition_for_client( struct channel_state_sample *last_sample = NULL; struct lttng_channel_trigger_list *channel_trigger_list = NULL; + rcu_read_lock(); + /* Find the channel associated with the condition. */ cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, channel_trigger_list, channel_triggers_ht_node) { @@ -765,6 +923,7 @@ int evaluate_channel_condition_for_client( *session_uid = channel_info->session_info->uid; *session_gid = channel_info->session_info->gid; end: + rcu_read_unlock(); return ret; } @@ -800,7 +959,6 @@ end: return session_name; } -/* This function must be called with the RCU read lock held. */ static int evaluate_session_condition_for_client( const struct lttng_condition *condition, @@ -814,6 +972,7 @@ int evaluate_session_condition_for_client( const char *session_name; struct session_info *session_info = NULL; + rcu_read_lock(); session_name = get_condition_session_name(condition); /* Find the session associated with the trigger. */ @@ -841,6 +1000,7 @@ int evaluate_session_condition_for_client( switch (lttng_condition_get_type(condition)) { case LTTNG_CONDITION_TYPE_SESSION_ROTATION_ONGOING: if (!session_info->rotation.ongoing) { + ret = 0; goto end_session_put; } @@ -866,10 +1026,10 @@ int evaluate_session_condition_for_client( end_session_put: session_info_put(session_info); end: + rcu_read_unlock(); return ret; } -/* This function must be called with the RCU read lock held. */ static int evaluate_condition_for_client(const struct lttng_trigger *trigger, const struct lttng_condition *condition, @@ -878,7 +1038,9 @@ int evaluate_condition_for_client(const struct lttng_trigger *trigger, { int ret; struct lttng_evaluation *evaluation = NULL; - struct notification_client_list client_list = { 0 }; + struct notification_client_list client_list = { + .lock = PTHREAD_MUTEX_INITIALIZER, + }; struct notification_client_list_element client_list_element = { 0 }; uid_t object_uid = 0; gid_t object_gid = 0; @@ -905,7 +1067,10 @@ int evaluate_condition_for_client(const struct lttng_trigger *trigger, ret = -1; goto end; } - + if (ret) { + /* Fatal error. */ + goto end; + } if (!evaluation) { /* Evaluation yielded nothing. Normal exit. */ DBG("[notification-thread] Newly subscribed-to condition evaluated to false, nothing to report to client"); @@ -917,7 +1082,7 @@ int evaluate_condition_for_client(const struct lttng_trigger *trigger, * Create a temporary client list with the client currently * subscribing. */ - cds_lfht_node_init(&client_list.notification_trigger_ht_node); + cds_lfht_node_init(&client_list.notification_trigger_clients_ht_node); CDS_INIT_LIST_HEAD(&client_list.list); client_list.trigger = trigger; @@ -941,7 +1106,7 @@ int notification_thread_client_subscribe(struct notification_client *client, enum lttng_notification_channel_status *_status) { int ret = 0; - struct notification_client_list *client_list; + struct notification_client_list *client_list = NULL; struct lttng_condition_list_element *condition_list_element = NULL; struct notification_client_list_element *client_list_element = NULL; enum lttng_notification_channel_status status = @@ -970,8 +1135,6 @@ int notification_thread_client_subscribe(struct notification_client *client, goto error; } - rcu_read_lock(); - /* * Add the newly-subscribed condition to the client's subscription list. */ @@ -987,20 +1150,24 @@ int notification_thread_client_subscribe(struct notification_client *client, * since this trigger is not registered yet. */ free(client_list_element); - goto end_unlock; + goto end; } /* * The condition to which the client just subscribed is evaluated * at this point so that conditions that are already TRUE result * in a notification being sent out. + * + * The client_list's trigger is used without locking the list itself. + * This is correct since the list doesn't own the trigger and the + * object is immutable. */ if (evaluate_condition_for_client(client_list->trigger, condition, client, state)) { WARN("[notification-thread] Evaluation of a condition on client subscription failed, aborting."); ret = -1; free(client_list_element); - goto end_unlock; + goto end; } /* @@ -1010,13 +1177,17 @@ int notification_thread_client_subscribe(struct notification_client *client, */ client_list_element->client = client; CDS_INIT_LIST_HEAD(&client_list_element->node); + + pthread_mutex_lock(&client_list->lock); cds_list_add(&client_list_element->node, &client_list->list); -end_unlock: - rcu_read_unlock(); + pthread_mutex_unlock(&client_list->lock); end: if (_status) { *_status = status; } + if (client_list) { + notification_client_list_put(client_list); + } return ret; error: free(condition_list_element); @@ -1072,23 +1243,24 @@ int notification_thread_client_unsubscribe( * Remove the client from the list of clients interested the trigger * matching the condition. */ - rcu_read_lock(); client_list = get_client_list_from_condition(state, condition); if (!client_list) { - goto end_unlock; + goto end; } + pthread_mutex_lock(&client_list->lock); cds_list_for_each_entry_safe(client_list_element, client_tmp, &client_list->list, node) { - if (client_list_element->client->socket != client->socket) { + if (client_list_element->client->id != client->id) { continue; } cds_list_del(&client_list_element->node); free(client_list_element); break; } -end_unlock: - rcu_read_unlock(); + pthread_mutex_unlock(&client_list->lock); + notification_client_list_put(client_list); + client_list = NULL; end: lttng_condition_destroy(condition); if (_status) { @@ -1097,29 +1269,33 @@ end: return 0; } +static +void free_notification_client_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct notification_client, rcu_node)); +} + static void notification_client_destroy(struct notification_client *client, struct notification_thread_state *state) { - struct lttng_condition_list_element *condition_list_element, *tmp; - if (!client) { return; } - /* Release all conditions to which the client was subscribed. */ - cds_list_for_each_entry_safe(condition_list_element, tmp, - &client->condition_list, node) { - (void) notification_thread_client_unsubscribe(client, - condition_list_element->condition, state, NULL); - } - + /* + * The client object is not reachable by other threads, no need to lock + * the client here. + */ if (client->socket >= 0) { (void) lttcomm_close_unix_sock(client->socket); + client->socket = -1; } + client->communication.active = false; lttng_dynamic_buffer_reset(&client->communication.inbound.buffer); lttng_dynamic_buffer_reset(&client->communication.outbound.buffer); - free(client); + pthread_mutex_destroy(&client->lock); + call_rcu(&client->rcu_node, free_notification_client_rcu); } /* @@ -1135,8 +1311,8 @@ struct notification_client *get_client_from_socket(int socket, struct notification_client *client = NULL; cds_lfht_lookup(state->client_socket_ht, - hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed), - match_client, + hash_client_socket(socket), + match_client_socket, (void *) (unsigned long) socket, &iter); node = cds_lfht_iter_get_node(&iter); @@ -1284,7 +1460,7 @@ struct lttng_session_trigger_list *get_session_trigger_list( goto end; } - list = caa_container_of(node, + list = caa_container_of(node, struct lttng_session_trigger_list, session_triggers_ht_node); end: @@ -1489,6 +1665,7 @@ struct session_info *find_or_create_session_info( if (!session) { ERR("[notification-thread] Failed to allocation session info for session \"%s\" (uid = %i, gid = %i)", name, uid, gid); + lttng_session_trigger_list_destroy(trigger_list); goto error; } trigger_list = NULL; @@ -1543,6 +1720,7 @@ int handle_notification_thread_command_add_channel( goto error; } + rcu_read_lock(); /* Build a list of all triggers applying to the new channel. */ cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element, node) { @@ -1555,6 +1733,7 @@ int handle_notification_thread_command_add_channel( new_element = zmalloc(sizeof(*new_element)); if (!new_element) { + rcu_read_unlock(); goto error; } CDS_INIT_LIST_HEAD(&new_element->node); @@ -1562,6 +1741,7 @@ int handle_notification_thread_command_add_channel( cds_list_add(&new_element->node, &trigger_list); trigger_count++; } + rcu_read_unlock(); DBG("[notification-thread] Found %i triggers that apply to newly added channel", trigger_count); @@ -1596,6 +1776,20 @@ error: return 1; } +static +void free_channel_trigger_list_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct lttng_channel_trigger_list, + rcu_node)); +} + +static +void free_channel_state_sample_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct channel_state_sample, + rcu_node)); +} + static int handle_notification_thread_command_remove_channel( struct notification_thread_state *state, @@ -1638,7 +1832,7 @@ int handle_notification_thread_command_remove_channel( free(trigger_list_element); } cds_lfht_del(state->channel_triggers_ht, node); - free(trigger_list); + call_rcu(&trigger_list->rcu_node, free_channel_trigger_list_rcu); /* Free sampled channel state. */ cds_lfht_lookup(state->channel_state_ht, @@ -1657,7 +1851,7 @@ int handle_notification_thread_command_remove_channel( channel_state_ht_node); cds_lfht_del(state->channel_state_ht, node); - free(sample); + call_rcu(&sample->rcu_node, free_channel_state_sample_rcu); } /* Remove the channel from the channels_ht and free it. */ @@ -1722,6 +1916,7 @@ int handle_notification_thread_command_session_rotation( struct notification_client_list *client_list; struct lttng_evaluation *evaluation = NULL; enum lttng_condition_type condition_type; + bool client_list_is_empty; trigger = trigger_list_element->trigger; condition = lttng_trigger_get_const_condition(trigger); @@ -1745,7 +1940,10 @@ int handle_notification_thread_command_session_rotation( client_list = get_client_list_from_condition(state, condition); assert(client_list); - if (cds_list_empty(&client_list->list)) { + pthread_mutex_lock(&client_list->lock); + client_list_is_empty = cds_list_empty(&client_list->list); + pthread_mutex_unlock(&client_list->lock); + if (client_list_is_empty) { /* * No clients interested in the evaluation's result, * skip it. @@ -1765,7 +1963,7 @@ int handle_notification_thread_command_session_rotation( /* Internal error */ ret = -1; cmd_result = LTTNG_ERR_UNK; - goto end; + goto put_list; } /* Dispatch evaluation result to all clients. */ @@ -1774,8 +1972,10 @@ int handle_notification_thread_command_session_rotation( session_info->uid, session_info->gid); lttng_evaluation_destroy(evaluation); +put_list: + notification_client_list_put(client_list); if (caa_unlikely(ret)) { - goto end; + break; } } end: @@ -1813,8 +2013,7 @@ int condition_is_supported(struct lttng_condition *condition) * buffers. Therefore, we reject triggers that require that * mechanism to be available to be evaluated. */ - ret = kernel_supports_ring_buffer_snapshot_sample_positions( - kernel_tracer_fd); + ret = kernel_supports_ring_buffer_snapshot_sample_positions(); break; } default: @@ -1884,6 +2083,7 @@ int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger, channels_ht_node) { struct lttng_trigger_list_element *trigger_list_element; struct lttng_channel_trigger_list *trigger_list; + struct cds_lfht_iter lookup_iter; if (!trigger_applies_to_channel(trigger, channel)) { continue; @@ -1893,8 +2093,8 @@ int bind_trigger_to_matching_channels(const struct lttng_trigger *trigger, hash_channel_key(&channel->key), match_channel_trigger_list, &channel->key, - &iter); - node = cds_lfht_iter_get_node(&iter); + &lookup_iter); + node = cds_lfht_iter_get_node(&lookup_iter); assert(node); trigger_list = caa_container_of(node, struct lttng_channel_trigger_list, @@ -1996,14 +2196,11 @@ int handle_notification_thread_command_register_trigger( * It is not skipped as this is the only action type currently * supported. */ - client_list = zmalloc(sizeof(*client_list)); + client_list = notification_client_list_create(trigger); if (!client_list) { ret = -1; goto error_free_ht_element; } - cds_lfht_node_init(&client_list->notification_trigger_ht_node); - CDS_INIT_LIST_HEAD(&client_list->list); - client_list->trigger = trigger; /* Build a list of clients to which this new trigger applies. */ cds_lfht_for_each_entry(state->client_socket_ht, &iter, client, @@ -2015,23 +2212,19 @@ int handle_notification_thread_command_register_trigger( client_list_element = zmalloc(sizeof(*client_list_element)); if (!client_list_element) { ret = -1; - goto error_free_client_list; + goto error_put_client_list; } CDS_INIT_LIST_HEAD(&client_list_element->node); client_list_element->client = client; cds_list_add(&client_list_element->node, &client_list->list); } - cds_lfht_add(state->notification_trigger_clients_ht, - lttng_condition_hash(condition), - &client_list->notification_trigger_ht_node); - switch (get_condition_binding_object(condition)) { case LTTNG_OBJECT_TYPE_SESSION: /* Add the trigger to the list if it matches a known session. */ ret = bind_trigger_to_matching_session(trigger, state); if (ret) { - goto error_free_client_list; + goto error_put_client_list; } break; case LTTNG_OBJECT_TYPE_CHANNEL: @@ -2041,7 +2234,7 @@ int handle_notification_thread_command_register_trigger( */ ret = bind_trigger_to_matching_channels(trigger, state); if (ret) { - goto error_free_client_list; + goto error_put_client_list; } break; case LTTNG_OBJECT_TYPE_NONE: @@ -2049,7 +2242,7 @@ int handle_notification_thread_command_register_trigger( default: ERR("[notification-thread] Unknown object type on which to bind a newly registered trigger was encountered"); ret = -1; - goto error_free_client_list; + goto error_put_client_list; } /* @@ -2077,13 +2270,15 @@ int handle_notification_thread_command_register_trigger( * current state. Otherwise, the next evaluation cycle may only see * that the evaluations remain the same (true for samples n-1 and n) and * the client will never know that the condition has been met. + * + * No need to lock the list here as it has not been published yet. */ cds_list_for_each_entry_safe(client_list_element, tmp, &client_list->list, node) { ret = evaluate_condition_for_client(trigger, condition, client_list_element->client, state); if (ret) { - goto error_free_client_list; + goto error_put_client_list; } } @@ -2091,31 +2286,31 @@ int handle_notification_thread_command_register_trigger( * Client list ownership transferred to the * notification_trigger_clients_ht. */ + publish_notification_client_list(state, client_list); client_list = NULL; *cmd_result = LTTNG_OK; -error_free_client_list: - if (client_list) { - cds_list_for_each_entry_safe(client_list_element, tmp, - &client_list->list, node) { - free(client_list_element); - } - free(client_list); - } + +error_put_client_list: + notification_client_list_put(client_list); + error_free_ht_element: free(trigger_ht_element); error: if (free_trigger) { - struct lttng_action *action = lttng_trigger_get_action(trigger); - - lttng_condition_destroy(condition); - lttng_action_destroy(action); lttng_trigger_destroy(trigger); } rcu_read_unlock(); return ret; } +static +void free_lttng_trigger_ht_element_rcu(struct rcu_head *node) +{ + free(caa_container_of(node, struct lttng_trigger_ht_element, + rcu_node)); +} + static int handle_notification_thread_command_unregister_trigger( struct notification_thread_state *state, @@ -2126,11 +2321,9 @@ int handle_notification_thread_command_unregister_trigger( struct cds_lfht_node *triggers_ht_node; struct lttng_channel_trigger_list *trigger_list; struct notification_client_list *client_list; - struct notification_client_list_element *client_list_element, *tmp; struct lttng_trigger_ht_element *trigger_ht_element = NULL; struct lttng_condition *condition = lttng_trigger_get_condition( trigger); - struct lttng_action *action; enum lttng_error_code cmd_reply; rcu_read_lock(); @@ -2179,25 +2372,19 @@ int handle_notification_thread_command_unregister_trigger( client_list = get_client_list_from_condition(state, condition); assert(client_list); - cds_list_for_each_entry_safe(client_list_element, tmp, - &client_list->list, node) { - free(client_list_element); - } - cds_lfht_del(state->notification_trigger_clients_ht, - &client_list->notification_trigger_ht_node); - free(client_list); + /* Put new reference and the hashtable's reference. */ + notification_client_list_put(client_list); + notification_client_list_put(client_list); + client_list = NULL; /* 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_ht, triggers_ht_node); - condition = lttng_trigger_get_condition(trigger_ht_element->trigger); - lttng_condition_destroy(condition); - action = lttng_trigger_get_action(trigger_ht_element->trigger); - lttng_action_destroy(action); + /* Release the ownership of the trigger. */ lttng_trigger_destroy(trigger_ht_element->trigger); - free(trigger_ht_element); + call_rcu(&trigger_ht_element->rcu_node, free_lttng_trigger_ht_element_rcu); end: rcu_read_unlock(); if (_cmd_reply) { @@ -2216,9 +2403,9 @@ int handle_notification_thread_command( struct notification_thread_command *cmd; /* Read the event pipe to put it back into a quiescent state. */ - ret = read(lttng_pipe_get_readfd(handle->cmd_queue.event_pipe), &counter, + ret = lttng_read(lttng_pipe_get_readfd(handle->cmd_queue.event_pipe), &counter, sizeof(counter)); - if (ret == -1) { + if (ret != sizeof(counter)) { goto error; } @@ -2288,7 +2475,12 @@ int handle_notification_thread_command( } end: cds_list_del(&cmd->cmd_list_node); - lttng_waiter_wake_up(&cmd->reply_waiter); + if (cmd->is_async) { + free(cmd); + cmd = NULL; + } else { + lttng_waiter_wake_up(&cmd->reply_waiter); + } pthread_mutex_unlock(&handle->cmd_queue.lock); return ret; error_unlock: @@ -2301,12 +2493,6 @@ error: return -1; } -static -unsigned long hash_client_socket(int socket) -{ - return hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed); -} - static int socket_set_non_blocking(int socket) { @@ -2330,11 +2516,14 @@ end: return ret; } +/* Client lock must be acquired by caller. */ static int client_reset_inbound_state(struct notification_client *client) { int ret; + ASSERT_LOCKED(client->lock); + ret = lttng_dynamic_buffer_set_size( &client->communication.inbound.buffer, 0); assert(!ret); @@ -2365,14 +2554,19 @@ int handle_notification_thread_client_connect( ret = -1; goto error; } + pthread_mutex_init(&client->lock, NULL); + client->id = state->next_notification_client_id++; CDS_INIT_LIST_HEAD(&client->condition_list); lttng_dynamic_buffer_init(&client->communication.inbound.buffer); lttng_dynamic_buffer_init(&client->communication.outbound.buffer); client->communication.inbound.expect_creds = true; + + pthread_mutex_lock(&client->lock); ret = client_reset_inbound_state(client); + pthread_mutex_unlock(&client->lock); if (ret) { ERR("[notification-thread] Failed to reset client communication's inbound state"); - ret = 0; + ret = 0; goto error; } @@ -2413,6 +2607,9 @@ int handle_notification_thread_client_connect( cds_lfht_add(state->client_socket_ht, hash_client_socket(client->socket), &client->client_socket_ht_node); + cds_lfht_add(state->client_id_ht, + hash_client_id(client->id), + &client->client_id_ht_node); rcu_read_unlock(); return ret; @@ -2421,9 +2618,44 @@ error: return ret; } -int handle_notification_thread_client_disconnect( - int client_socket, +/* RCU read-lock must be held by the caller. */ +/* Client lock must be held by the caller */ +static +int notification_thread_client_disconnect( + struct notification_client *client, struct notification_thread_state *state) +{ + int ret; + struct lttng_condition_list_element *condition_list_element, *tmp; + + /* Acquire the client lock to disable its communication atomically. */ + client->communication.active = false; + ret = lttng_poll_del(&state->events, client->socket); + if (ret) { + ERR("[notification-thread] Failed to remove client socket %d from poll set", + client->socket); + } + + cds_lfht_del(state->client_socket_ht, &client->client_socket_ht_node); + cds_lfht_del(state->client_id_ht, &client->client_id_ht_node); + + /* Release all conditions to which the client was subscribed. */ + cds_list_for_each_entry_safe(condition_list_element, tmp, + &client->condition_list, node) { + (void) notification_thread_client_unsubscribe(client, + condition_list_element->condition, state, NULL); + } + + /* + * Client no longer accessible to other threads (through the + * client lists). + */ + notification_client_destroy(client, state); + return ret; +} + +int handle_notification_thread_client_disconnect( + int client_socket, struct notification_thread_state *state) { int ret = 0; struct notification_client *client; @@ -2440,13 +2672,9 @@ int handle_notification_thread_client_disconnect( goto end; } - ret = lttng_poll_del(&state->events, client_socket); - if (ret) { - ERR("[notification-thread] Failed to remove client socket from poll set"); - } - cds_lfht_del(state->client_socket_ht, - &client->client_socket_ht_node); - notification_client_destroy(client, state); + pthread_mutex_lock(&client->lock); + ret = notification_thread_client_disconnect(client, state); + pthread_mutex_unlock(&client->lock); end: rcu_read_unlock(); return ret; @@ -2462,11 +2690,13 @@ int handle_notification_thread_client_disconnect_all( rcu_read_lock(); DBG("[notification-thread] Closing all client connections"); cds_lfht_for_each_entry(state->client_socket_ht, &iter, client, - client_socket_ht_node) { + client_socket_ht_node) { int ret; - ret = handle_notification_thread_client_disconnect( - client->socket, state); + pthread_mutex_lock(&client->lock); + ret = notification_thread_client_disconnect( + client, state); + pthread_mutex_unlock(&client->lock); if (ret) { error_encoutered = true; } @@ -2482,6 +2712,7 @@ int handle_notification_thread_trigger_unregister_all( struct cds_lfht_iter iter; struct lttng_trigger_ht_element *trigger_ht_element; + rcu_read_lock(); cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element, node) { int ret = handle_notification_thread_command_unregister_trigger( @@ -2490,15 +2721,67 @@ int handle_notification_thread_trigger_unregister_all( error_occurred = true; } } + rcu_read_unlock(); return error_occurred ? -1 : 0; } static -int client_flush_outgoing_queue(struct notification_client *client, +int client_handle_transmission_status( + struct notification_client *client, + enum client_transmission_status transmission_status, + struct notification_thread_state *state) +{ + int ret = 0; + + switch (transmission_status) { + case CLIENT_TRANSMISSION_STATUS_COMPLETE: + ret = lttng_poll_mod(&state->events, client->socket, + CLIENT_POLL_MASK_IN); + if (ret) { + goto end; + } + + client->communication.outbound.queued_command_reply = false; + client->communication.outbound.dropped_notification = false; + break; + case CLIENT_TRANSMISSION_STATUS_QUEUED: + /* + * We want to be notified whenever there is buffer space + * available to send the rest of the payload. + */ + ret = lttng_poll_mod(&state->events, client->socket, + CLIENT_POLL_MASK_IN_OUT); + if (ret) { + goto end; + } + break; + case CLIENT_TRANSMISSION_STATUS_FAIL: + ret = notification_thread_client_disconnect(client, state); + if (ret) { + goto end; + } + break; + case CLIENT_TRANSMISSION_STATUS_ERROR: + ret = -1; + goto end; + default: + abort(); + } +end: + return ret; +} + +/* Client lock must be acquired by caller. */ +static +enum client_transmission_status client_flush_outgoing_queue( + struct notification_client *client, struct notification_thread_state *state) { ssize_t ret; size_t to_send_count; + enum client_transmission_status status; + + ASSERT_LOCKED(client->lock); assert(client->communication.outbound.buffer.size != 0); to_send_count = client->communication.outbound.buffer.size; @@ -2508,8 +2791,7 @@ int client_flush_outgoing_queue(struct notification_client *client, ret = lttcomm_send_unix_sock_non_block(client->socket, client->communication.outbound.buffer.data, to_send_count); - if ((ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) || - (ret > 0 && ret < to_send_count)) { + if ((ret >= 0 && ret < to_send_count)) { DBG("[notification-thread] Client (socket fd = %i) outgoing queue could not be completely flushed", client->socket); to_send_count -= max(ret, 0); @@ -2522,42 +2804,29 @@ int client_flush_outgoing_queue(struct notification_client *client, &client->communication.outbound.buffer, to_send_count); if (ret) { + status = CLIENT_TRANSMISSION_STATUS_ERROR; goto error; } - - /* - * We want to be notified whenever there is buffer space - * available to send the rest of the payload. - */ - ret = lttng_poll_mod(&state->events, client->socket, - CLIENT_POLL_MASK_IN_OUT); - if (ret) { - goto error; - } + status = CLIENT_TRANSMISSION_STATUS_QUEUED; } else if (ret < 0) { /* Generic error, disconnect the client. */ - ERR("[notification-thread] Failed to send flush outgoing queue, disconnecting client (socket fd = %i)", + ERR("[notification-thread] Failed to flush outgoing queue, disconnecting client (socket fd = %i)", client->socket); - ret = handle_notification_thread_client_disconnect( - client->socket, state); - if (ret) { - goto error; - } + status = CLIENT_TRANSMISSION_STATUS_FAIL; } else { /* No error and flushed the queue completely. */ ret = lttng_dynamic_buffer_set_size( &client->communication.outbound.buffer, 0); if (ret) { + status = CLIENT_TRANSMISSION_STATUS_ERROR; goto error; } - ret = lttng_poll_mod(&state->events, client->socket, - CLIENT_POLL_MASK_IN); - if (ret) { - goto error; - } + status = CLIENT_TRANSMISSION_STATUS_COMPLETE; + } - client->communication.outbound.queued_command_reply = false; - client->communication.outbound.dropped_notification = false; + ret = client_handle_transmission_status(client, status, state); + if (ret) { + goto error; } return 0; @@ -2565,6 +2834,7 @@ error: return -1; } +/* Client lock must be acquired by caller. */ static int client_send_command_reply(struct notification_client *client, struct notification_thread_state *state, @@ -2580,6 +2850,8 @@ int client_send_command_reply(struct notification_client *client, }; char buffer[sizeof(msg) + sizeof(reply)]; + ASSERT_LOCKED(client->lock); + if (client->communication.outbound.queued_command_reply) { /* Protocol error. */ goto error; @@ -2612,6 +2884,194 @@ error: return -1; } +static +int client_handle_message_unknown(struct notification_client *client, + struct notification_thread_state *state) +{ + int ret; + + pthread_mutex_lock(&client->lock); + + /* + * Receiving message header. The function will be called again + * once the rest of the message as been received and can be + * interpreted. + */ + const struct lttng_notification_channel_message *msg; + + assert(sizeof(*msg) == client->communication.inbound.buffer.size); + msg = (const struct lttng_notification_channel_message *) + client->communication.inbound.buffer.data; + + if (msg->size == 0 || + msg->size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) { + ERR("[notification-thread] Invalid notification channel message: length = %u", + msg->size); + ret = -1; + goto end; + } + + switch (msg->type) { + case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE: + case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE: + case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE: + break; + default: + ret = -1; + ERR("[notification-thread] Invalid notification channel message: unexpected message type"); + goto end; + } + + client->communication.inbound.bytes_to_receive = msg->size; + client->communication.inbound.msg_type = + (enum lttng_notification_channel_message_type) msg->type; + ret = lttng_dynamic_buffer_set_size( + &client->communication.inbound.buffer, msg->size); +end: + pthread_mutex_unlock(&client->lock); + return ret; +} + +static +int client_handle_message_handshake(struct notification_client *client, + struct notification_thread_state *state) +{ + int ret; + struct lttng_notification_channel_command_handshake *handshake_client; + const struct lttng_notification_channel_command_handshake handshake_reply = { + .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR, + .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR, + }; + const struct lttng_notification_channel_message msg_header = { + .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE, + .size = sizeof(handshake_reply), + }; + enum lttng_notification_channel_status status = + LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; + char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)]; + + pthread_mutex_lock(&client->lock); + + memcpy(send_buffer, &msg_header, sizeof(msg_header)); + memcpy(send_buffer + sizeof(msg_header), &handshake_reply, + sizeof(handshake_reply)); + + handshake_client = + (struct lttng_notification_channel_command_handshake *) + client->communication.inbound.buffer + .data; + client->major = handshake_client->major; + client->minor = handshake_client->minor; + if (!client->communication.inbound.creds_received) { + ERR("[notification-thread] No credentials received from client"); + ret = -1; + goto end; + } + + client->uid = LTTNG_SOCK_GET_UID_CRED( + &client->communication.inbound.creds); + client->gid = LTTNG_SOCK_GET_GID_CRED( + &client->communication.inbound.creds); + DBG("[notification-thread] Received handshake from client (uid = %u, gid = %u) with version %i.%i", + client->uid, client->gid, (int) client->major, + (int) client->minor); + + if (handshake_client->major != + LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) { + status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNSUPPORTED_VERSION; + } + + ret = lttng_dynamic_buffer_append( + &client->communication.outbound.buffer, send_buffer, + sizeof(send_buffer)); + if (ret) { + ERR("[notification-thread] Failed to send protocol version to notification channel client"); + goto end; + } + + client->validated = true; + client->communication.active = true; + + ret = client_flush_outgoing_queue(client, state); + if (ret) { + goto end; + } + + ret = client_send_command_reply(client, state, status); + if (ret) { + ERR("[notification-thread] Failed to send reply to notification channel client"); + goto end; + } + + /* Set reception state to receive the next message header. */ + ret = client_reset_inbound_state(client); + if (ret) { + ERR("[notification-thread] Failed to reset client communication's inbound state"); + goto end; + } + +end: + pthread_mutex_unlock(&client->lock); + return ret; +} + +static +int client_handle_message_subscription( + struct notification_client *client, + enum lttng_notification_channel_message_type msg_type, + struct notification_thread_state *state) +{ + int ret; + struct lttng_condition *condition; + enum lttng_notification_channel_status status = + LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; + struct lttng_payload_view condition_view = + lttng_payload_view_from_dynamic_buffer( + &client->communication.inbound.buffer, + 0, -1); + size_t expected_condition_size; + + pthread_mutex_lock(&client->lock); + expected_condition_size = client->communication.inbound.buffer.size; + pthread_mutex_unlock(&client->lock); + + ret = lttng_condition_create_from_payload(&condition_view, &condition); + if (ret != expected_condition_size) { + ERR("[notification-thread] Malformed condition received from client"); + goto end; + } + + if (msg_type == LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE) { + ret = notification_thread_client_subscribe( + client, condition, state, &status); + } else { + ret = notification_thread_client_unsubscribe( + client, condition, state, &status); + } + if (ret) { + goto end; + } + + pthread_mutex_lock(&client->lock); + ret = client_send_command_reply(client, state, status); + if (ret) { + ERR("[notification-thread] Failed to send reply to notification channel client"); + goto end_unlock; + } + + /* Set reception state to receive the next message header. */ + ret = client_reset_inbound_state(client); + if (ret) { + ERR("[notification-thread] Failed to reset client communication's inbound state"); + goto end_unlock; + } + +end_unlock: + pthread_mutex_unlock(&client->lock); +end: + return ret; +} + static int client_dispatch_message(struct notification_client *client, struct notification_thread_state *state) @@ -2631,158 +3091,19 @@ int client_dispatch_message(struct notification_client *client, switch (client->communication.inbound.msg_type) { case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN: { - /* - * Receiving message header. The function will be called again - * once the rest of the message as been received and can be - * interpreted. - */ - const struct lttng_notification_channel_message *msg; - - assert(sizeof(*msg) == - client->communication.inbound.buffer.size); - msg = (const struct lttng_notification_channel_message *) - client->communication.inbound.buffer.data; - - if (msg->size == 0 || msg->size > DEFAULT_MAX_NOTIFICATION_CLIENT_MESSAGE_PAYLOAD_SIZE) { - ERR("[notification-thread] Invalid notification channel message: length = %u", msg->size); - ret = -1; - goto end; - } - - switch (msg->type) { - case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE: - case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE: - case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE: - break; - default: - ret = -1; - ERR("[notification-thread] Invalid notification channel message: unexpected message type"); - goto end; - } - - client->communication.inbound.bytes_to_receive = msg->size; - client->communication.inbound.msg_type = - (enum lttng_notification_channel_message_type) msg->type; - ret = lttng_dynamic_buffer_set_size( - &client->communication.inbound.buffer, msg->size); - if (ret) { - goto end; - } + ret = client_handle_message_unknown(client, state); break; } case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE: { - struct lttng_notification_channel_command_handshake *handshake_client; - struct lttng_notification_channel_command_handshake handshake_reply = { - .major = LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR, - .minor = LTTNG_NOTIFICATION_CHANNEL_VERSION_MINOR, - }; - struct lttng_notification_channel_message msg_header = { - .type = LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE, - .size = sizeof(handshake_reply), - }; - enum lttng_notification_channel_status status = - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; - char send_buffer[sizeof(msg_header) + sizeof(handshake_reply)]; - - memcpy(send_buffer, &msg_header, sizeof(msg_header)); - memcpy(send_buffer + sizeof(msg_header), &handshake_reply, - sizeof(handshake_reply)); - - handshake_client = - (struct lttng_notification_channel_command_handshake *) - client->communication.inbound.buffer.data; - client->major = handshake_client->major; - client->minor = handshake_client->minor; - if (!client->communication.inbound.creds_received) { - ERR("[notification-thread] No credentials received from client"); - ret = -1; - goto end; - } - - client->uid = LTTNG_SOCK_GET_UID_CRED( - &client->communication.inbound.creds); - client->gid = LTTNG_SOCK_GET_GID_CRED( - &client->communication.inbound.creds); - DBG("[notification-thread] Received handshake from client (uid = %u, gid = %u) with version %i.%i", - client->uid, client->gid, (int) client->major, - (int) client->minor); - - if (handshake_client->major != LTTNG_NOTIFICATION_CHANNEL_VERSION_MAJOR) { - status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNSUPPORTED_VERSION; - } - - ret = lttng_dynamic_buffer_append(&client->communication.outbound.buffer, - send_buffer, sizeof(send_buffer)); - if (ret) { - ERR("[notification-thread] Failed to send protocol version to notification channel client"); - goto end; - } - - ret = client_flush_outgoing_queue(client, state); - if (ret) { - goto end; - } - - ret = client_send_command_reply(client, state, status); - if (ret) { - ERR("[notification-thread] Failed to send reply to notification channel client"); - goto end; - } - - /* Set reception state to receive the next message header. */ - ret = client_reset_inbound_state(client); - if (ret) { - ERR("[notification-thread] Failed to reset client communication's inbound state"); - goto end; - } - client->validated = true; + ret = client_handle_message_handshake(client, state); break; } case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE: case LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNSUBSCRIBE: { - struct lttng_condition *condition; - enum lttng_notification_channel_status status = - LTTNG_NOTIFICATION_CHANNEL_STATUS_OK; - const struct lttng_buffer_view condition_view = - lttng_buffer_view_from_dynamic_buffer( - &client->communication.inbound.buffer, - 0, -1); - size_t expected_condition_size = - client->communication.inbound.buffer.size; - - ret = lttng_condition_create_from_buffer(&condition_view, - &condition); - if (ret != expected_condition_size) { - ERR("[notification-thread] Malformed condition received from client"); - goto end; - } - - if (client->communication.inbound.msg_type == - LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_SUBSCRIBE) { - ret = notification_thread_client_subscribe(client, - condition, state, &status); - } else { - ret = notification_thread_client_unsubscribe(client, - condition, state, &status); - } - if (ret) { - goto end; - } - - ret = client_send_command_reply(client, state, status); - if (ret) { - ERR("[notification-thread] Failed to send reply to notification channel client"); - goto end; - } - - /* Set reception state to receive the next message header. */ - ret = client_reset_inbound_state(client); - if (ret) { - ERR("[notification-thread] Failed to reset client communication's inbound state"); - goto end; - } + ret = client_handle_message_subscription(client, + client->communication.inbound.msg_type, state); break; } default: @@ -2800,6 +3121,7 @@ int handle_notification_thread_client_in( struct notification_client *client; ssize_t recv_ret; size_t offset; + bool message_is_complete = false; client = get_client_from_socket(socket, state); if (!client) { @@ -2808,6 +3130,7 @@ int handle_notification_thread_client_in( goto end; } + pthread_mutex_lock(&client->lock); offset = client->communication.inbound.buffer.size - client->communication.inbound.bytes_to_receive; if (client->communication.inbound.expect_creds) { @@ -2824,12 +3147,17 @@ int handle_notification_thread_client_in( client->communication.inbound.buffer.data + offset, client->communication.inbound.bytes_to_receive); } + if (recv_ret >= 0) { + client->communication.inbound.bytes_to_receive -= recv_ret; + message_is_complete = client->communication.inbound + .bytes_to_receive == 0; + } + pthread_mutex_unlock(&client->lock); if (recv_ret < 0) { goto error_disconnect_client; } - client->communication.inbound.bytes_to_receive -= recv_ret; - if (client->communication.inbound.bytes_to_receive == 0) { + if (message_is_complete) { ret = client_dispatch_message(client, state); if (ret) { /* @@ -2838,13 +3166,13 @@ int handle_notification_thread_client_in( */ goto error_disconnect_client; } - } else { - goto end; } end: return ret; error_disconnect_client: - ret = handle_notification_thread_client_disconnect(socket, state); + pthread_mutex_lock(&client->lock); + ret = notification_thread_client_disconnect(client, state); + pthread_mutex_unlock(&client->lock); return ret; } @@ -2862,7 +3190,9 @@ int handle_notification_thread_client_out( goto end; } + pthread_mutex_lock(&client->lock); ret = client_flush_outgoing_queue(client, state); + pthread_mutex_unlock(&client->lock); if (ret) { goto end; } @@ -2893,7 +3223,7 @@ bool evaluate_buffer_usage_condition(const struct lttng_condition *condition, * forego this double-multiplication or it could be performed * as fixed-point math. * - * Note that caching should accomodate the case where the + * Note that caching should accommodates the case where the * condition applies to multiple channels (i.e. don't assume * that all channels matching my_chann* have the same size...) */ @@ -3033,8 +3363,7 @@ end: } static -int client_enqueue_dropped_notification(struct notification_client *client, - struct notification_thread_state *state) +int client_enqueue_dropped_notification(struct notification_client *client) { int ret; struct lttng_notification_channel_message msg = { @@ -3042,21 +3371,56 @@ int client_enqueue_dropped_notification(struct notification_client *client, .size = 0, }; + ASSERT_LOCKED(client->lock); + ret = lttng_dynamic_buffer_append( &client->communication.outbound.buffer, &msg, sizeof(msg)); return ret; } +/* + * Permission checks relative to notification channel clients are performed + * here. Notice how object, client, and trigger credentials are involved in + * this check. + * + * The `object` credentials are the credentials associated with the "subject" + * of a condition. For instance, a `rotation completed` condition applies + * to a session. When that condition is met, it will produce an evaluation + * against a session. Hence, in this case, the `object` credentials are the + * credentials of the "subject" session. + * + * The `trigger` credentials are the credentials of the user that registered the + * trigger. + * + * The `client` credentials are the credentials of the user that created a given + * notification channel. + * + * In terms of visibility, it is expected that non-privilieged users can only + * register triggers against "their" objects (their own sessions and + * applications they are allowed to interact with). They can then open a + * notification channel and subscribe to notifications associated with those + * triggers. + * + * As for privilieged users, they can register triggers against the objects of + * other users. They can then subscribe to the notifications associated to their + * triggers. Privilieged users _can't_ subscribe to the notifications of + * triggers owned by other users; they must create their own triggers. + * + * This is more a concern of usability than security. It would be difficult for + * a root user reliably subscribe to a specific set of conditions without + * interference from external users (those could, for instance, unregister + * their triggers). + */ static int send_evaluation_to_clients(const struct lttng_trigger *trigger, const struct lttng_evaluation *evaluation, struct notification_client_list* client_list, struct notification_thread_state *state, - uid_t channel_uid, gid_t channel_gid) + uid_t object_uid, gid_t object_gid) { int ret = 0; - struct lttng_dynamic_buffer msg_buffer; + struct lttng_payload msg_payload; struct notification_client_list_element *client_list_element, *tmp; const struct lttng_notification notification = { .condition = (struct lttng_condition *) lttng_trigger_get_const_condition(trigger), @@ -3065,16 +3429,17 @@ int send_evaluation_to_clients(const struct lttng_trigger *trigger, struct lttng_notification_channel_message msg_header = { .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION, }; + const struct lttng_credentials *trigger_creds = lttng_trigger_get_credentials(trigger); - lttng_dynamic_buffer_init(&msg_buffer); + lttng_payload_init(&msg_payload); - ret = lttng_dynamic_buffer_append(&msg_buffer, &msg_header, + ret = lttng_dynamic_buffer_append(&msg_payload.buffer, &msg_header, sizeof(msg_header)); if (ret) { goto end; } - ret = lttng_notification_serialize(¬ification, &msg_buffer); + ret = lttng_notification_serialize(¬ification, &msg_payload); if (ret) { ERR("[notification-thread] Failed to serialize notification"); ret = -1; @@ -3082,23 +3447,32 @@ int send_evaluation_to_clients(const struct lttng_trigger *trigger, } /* Update payload size. */ - ((struct lttng_notification_channel_message * ) msg_buffer.data)->size = - (uint32_t) (msg_buffer.size - sizeof(msg_header)); + ((struct lttng_notification_channel_message *) msg_payload.buffer.data) + ->size = (uint32_t)( + msg_payload.buffer.size - sizeof(msg_header)); + pthread_mutex_lock(&client_list->lock); cds_list_for_each_entry_safe(client_list_element, tmp, &client_list->list, node) { struct notification_client *client = client_list_element->client; - if (client->uid != channel_uid && client->gid != channel_gid && + ret = 0; + pthread_mutex_lock(&client->lock); + if (client->uid != object_uid && client->gid != object_gid && client->uid != 0) { /* Client is not allowed to monitor this channel. */ - DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this channel"); - continue; + DBG("[notification-thread] Skipping client at it does not have the object permission to receive notification for this trigger"); + goto unlock_client; + } + + if (client->uid != trigger_creds->uid && client->gid != trigger_creds->gid) { + DBG("[notification-thread] Skipping client at it does not have the permission to receive notification for this trigger"); + goto unlock_client; } DBG("[notification-thread] Sending notification to client (fd = %i, %zu bytes)", - client->socket, msg_buffer.size); + client->socket, msg_payload.buffer.size); if (client->communication.outbound.buffer.size) { /* * Outgoing data is already buffered for this client; @@ -3112,29 +3486,37 @@ int send_evaluation_to_clients(const struct lttng_trigger *trigger, if (!client->communication.outbound.dropped_notification) { client->communication.outbound.dropped_notification = true; ret = client_enqueue_dropped_notification( - client, state); + client); if (ret) { - goto end; + goto unlock_client; } } - continue; + goto unlock_client; } ret = lttng_dynamic_buffer_append_buffer( &client->communication.outbound.buffer, - &msg_buffer); + &msg_payload.buffer); if (ret) { - goto end; + goto unlock_client; } ret = client_flush_outgoing_queue(client, state); if (ret) { - goto end; + goto unlock_client; + } +unlock_client: + pthread_mutex_unlock(&client->lock); + if (ret) { + goto end_unlock_list; } } ret = 0; + +end_unlock_list: + pthread_mutex_unlock(&client_list->lock); end: - lttng_dynamic_buffer_reset(&msg_buffer); + lttng_payload_reset(&msg_payload); return ret; } @@ -3273,13 +3655,15 @@ int handle_notification_thread_channel_sample( trigger_list = caa_container_of(node, struct lttng_channel_trigger_list, channel_triggers_ht_node); cds_list_for_each_entry(trigger_list_element, &trigger_list->list, - node) { + node) { const struct lttng_condition *condition; const struct lttng_action *action; const struct lttng_trigger *trigger; - struct notification_client_list *client_list; + struct notification_client_list *client_list = NULL; struct lttng_evaluation *evaluation = NULL; + bool client_list_is_empty; + ret = 0; trigger = trigger_list_element->trigger; condition = lttng_trigger_get_const_condition(trigger); assert(condition); @@ -3295,12 +3679,13 @@ int handle_notification_thread_channel_sample( */ client_list = get_client_list_from_condition(state, condition); assert(client_list); - if (cds_list_empty(&client_list->list)) { + client_list_is_empty = cds_list_empty(&client_list->list); + if (client_list_is_empty) { /* * No clients interested in the evaluation's result, * skip it. */ - continue; + goto put_list; } ret = evaluate_buffer_condition(condition, &evaluation, state, @@ -3310,11 +3695,11 @@ int handle_notification_thread_channel_sample( latest_session_consumed_total, channel_info); if (caa_unlikely(ret)) { - goto end_unlock; + goto put_list; } if (caa_likely(!evaluation)) { - continue; + goto put_list; } /* Dispatch evaluation result to all clients. */ @@ -3323,8 +3708,10 @@ int handle_notification_thread_channel_sample( channel_info->session_info->uid, channel_info->session_info->gid); lttng_evaluation_destroy(evaluation); +put_list: + notification_client_list_put(client_list); if (caa_unlikely(ret)) { - goto end_unlock; + break; } } end_unlock: