--- /dev/null
+/*
+ * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * 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.
+ *
+ * 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
+#include <urcu.h>
+#include <urcu/rculfhash.h>
+
+#include "notification-thread.h"
+#include "notification-thread-events.h"
+#include "notification-thread-commands.h"
+#include <common/defaults.h>
+#include <common/error.h>
+#include <common/futex.h>
+#include <common/unix.h>
+#include <common/dynamic-buffer.h>
+#include <common/hashtable/utils.h>
+#include <common/sessiond-comm/sessiond-comm.h>
+#include <common/macros.h>
+#include <lttng/condition/condition.h>
+#include <lttng/action/action.h>
+#include <lttng/notification/notification-internal.h>
+#include <lttng/condition/condition-internal.h>
+#include <lttng/condition/buffer-usage-internal.h>
+#include <lttng/notification/channel-internal.h>
+#include <time.h>
+#include <unistd.h>
+#include <assert.h>
+#include <inttypes.h>
+
+#define CLIENT_POLL_MASK_IN (LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP)
+#define CLIENT_POLL_MASK_IN_OUT (CLIENT_POLL_MASK_IN | LPOLLOUT)
+
+struct lttng_trigger_list_element {
+ struct lttng_trigger *trigger;
+ struct cds_list_head node;
+};
+
+struct lttng_channel_trigger_list {
+ struct channel_key channel_key;
+ struct cds_list_head list;
+ struct cds_lfht_node channel_triggers_ht_node;
+};
+
+struct lttng_trigger_ht_element {
+ struct lttng_trigger *trigger;
+ struct cds_lfht_node node;
+};
+
+struct lttng_condition_list_element {
+ struct lttng_condition *condition;
+ struct cds_list_head node;
+};
+
+struct notification_client_list_element {
+ struct notification_client *client;
+ struct cds_list_head node;
+};
+
+struct notification_client_list {
+ struct lttng_trigger *trigger;
+ struct cds_list_head list;
+ struct cds_lfht_node notification_trigger_ht_node;
+};
+
+struct notification_client {
+ int socket;
+ /* Client protocol version. */
+ uint8_t major, minor;
+ uid_t uid;
+ gid_t gid;
+ /*
+ * Indicates if the credentials and versions of the client has been
+ * checked.
+ */
+ bool validated;
+ /*
+ * Conditions to which the client's notification channel is subscribed.
+ * List of struct lttng_condition_list_node. The condition member is
+ * owned by the client.
+ */
+ struct cds_list_head condition_list;
+ struct cds_lfht_node client_socket_ht_node;
+ struct {
+ struct {
+ struct lttng_dynamic_buffer buffer;
+ /* Bytes left to receive for the current message. */
+ size_t bytes_to_receive;
+ /* Type of the message being received. */
+ enum lttng_notification_channel_message_type msg_type;
+ /*
+ * Indicates whether or not credentials are expected
+ * from the client.
+ */
+ bool receive_creds;
+ /*
+ * Indicates whether or not credentials were received
+ * from the client.
+ */
+ bool creds_received;
+ lttng_sock_cred creds;
+ } inbound;
+ struct {
+ /*
+ * Indicates whether or not a notification addressed to
+ * this client was dropped because a command reply was
+ * already buffered.
+ *
+ * A notification is dropped whenever the buffer is not
+ * empty.
+ */
+ bool dropped_notification;
+ /*
+ * Indicates whether or not a command reply is already
+ * buffered. In this case, it means that the client is
+ * not consuming command replies before emitting a new
+ * one. This could be caused by a protocol error or a
+ * misbehaving/malicious client.
+ */
+ bool queued_command_reply;
+ struct lttng_dynamic_buffer buffer;
+ } outbound;
+ } communication;
+};
+
+struct channel_state_sample {
+ struct channel_key key;
+ struct cds_lfht_node channel_state_ht_node;
+ uint64_t highest_usage;
+ uint64_t lowest_usage;
+};
+
+static
+int match_client(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;
+
+ client = caa_container_of(node, struct notification_client,
+ client_socket_ht_node);
+
+ return !!(client->socket == socket);
+}
+
+static
+int match_channel_trigger_list(struct cds_lfht_node *node, const void *key)
+{
+ struct channel_key *channel_key = (struct channel_key *) key;
+ struct lttng_channel_trigger_list *trigger_list;
+
+ trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
+ channel_triggers_ht_node);
+
+ return !!((channel_key->key == trigger_list->channel_key.key) &&
+ (channel_key->domain == trigger_list->channel_key.domain));
+}
+
+static
+int match_channel_state_sample(struct cds_lfht_node *node, const void *key)
+{
+ struct channel_key *channel_key = (struct channel_key *) key;
+ struct channel_state_sample *sample;
+
+ sample = caa_container_of(node, struct channel_state_sample,
+ channel_state_ht_node);
+
+ return !!((channel_key->key == sample->key.key) &&
+ (channel_key->domain == sample->key.domain));
+}
+
+static
+int match_channel_info(struct cds_lfht_node *node, const void *key)
+{
+ struct channel_key *channel_key = (struct channel_key *) key;
+ struct channel_info *channel_info;
+
+ channel_info = caa_container_of(node, struct channel_info,
+ channels_ht_node);
+
+ return !!((channel_key->key == channel_info->key.key) &&
+ (channel_key->domain == channel_info->key.domain));
+}
+
+static
+int match_condition(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;
+
+ trigger = 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);
+}
+
+static
+int match_client_list(struct cds_lfht_node *node, const void *key)
+{
+ struct lttng_trigger *trigger_key = (struct lttng_trigger *) key;
+ struct notification_client_list *client_list;
+ struct lttng_condition *condition;
+ struct lttng_condition *condition_key = lttng_trigger_get_condition(
+ trigger_key);
+
+ assert(condition_key);
+
+ client_list = caa_container_of(node, struct notification_client_list,
+ notification_trigger_ht_node);
+ condition = lttng_trigger_get_condition(client_list->trigger);
+
+ return !!lttng_condition_is_equal(condition_key, condition);
+}
+
+static
+int match_client_list_condition(struct cds_lfht_node *node, const void *key)
+{
+ struct lttng_condition *condition_key = (struct lttng_condition *) key;
+ struct notification_client_list *client_list;
+ struct lttng_condition *condition;
+
+ assert(condition_key);
+
+ client_list = caa_container_of(node, struct notification_client_list,
+ notification_trigger_ht_node);
+ condition = lttng_trigger_get_condition(client_list->trigger);
+
+ return !!lttng_condition_is_equal(condition_key, condition);
+}
+
+static
+unsigned long lttng_condition_buffer_usage_hash(
+ struct lttng_condition *_condition)
+{
+ unsigned long hash = 0;
+ struct lttng_condition_buffer_usage *condition;
+
+ condition = container_of(_condition,
+ struct lttng_condition_buffer_usage, parent);
+
+ if (condition->session_name) {
+ hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
+ }
+ if (condition->channel_name) {
+ hash ^= hash_key_str(condition->session_name, lttng_ht_seed);
+ }
+ if (condition->domain.set) {
+ hash ^= hash_key_ulong(
+ (void *) condition->domain.type,
+ lttng_ht_seed);
+ }
+ if (condition->threshold_ratio.set) {
+ uint64_t val;
+
+ val = condition->threshold_ratio.value * (double) UINT32_MAX;
+ hash ^= hash_key_u64(&val, lttng_ht_seed);
+ } else if (condition->threshold_ratio.set) {
+ uint64_t val;
+
+ val = condition->threshold_bytes.value;
+ hash ^= hash_key_u64(&val, lttng_ht_seed);
+ }
+ return hash;
+}
+
+/*
+ * The lttng_condition hashing code is kept in this file (rather than
+ * condition.c) since it makes use of GPLv2 code (hashtable utils), which we
+ * don't want to link in liblttng-ctl.
+ */
+static
+unsigned long lttng_condition_hash(struct lttng_condition *condition)
+{
+ switch (condition->type) {
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
+ return lttng_condition_buffer_usage_hash(condition);
+ default:
+ ERR("[notification-thread] Unexpected condition type caught");
+ abort();
+ }
+}
+
+static
+void channel_info_destroy(struct channel_info *channel_info)
+{
+ if (!channel_info) {
+ return;
+ }
+
+ if (channel_info->session_name) {
+ free(channel_info->session_name);
+ }
+ if (channel_info->channel_name) {
+ free(channel_info->channel_name);
+ }
+ free(channel_info);
+}
+
+static
+struct channel_info *channel_info_copy(struct channel_info *channel_info)
+{
+ struct channel_info *copy = zmalloc(sizeof(*channel_info));
+
+ assert(channel_info);
+ assert(channel_info->session_name);
+ assert(channel_info->channel_name);
+
+ if (!copy) {
+ goto end;
+ }
+
+ memcpy(copy, channel_info, sizeof(*channel_info));
+ copy->session_name = NULL;
+ copy->channel_name = NULL;
+
+ copy->session_name = strdup(channel_info->session_name);
+ if (!copy->session_name) {
+ goto error;
+ }
+ copy->channel_name = strdup(channel_info->channel_name);
+ if (!copy->channel_name) {
+ goto error;
+ }
+ cds_lfht_node_init(&channel_info->channels_ht_node);
+end:
+ return copy;
+error:
+ channel_info_destroy(copy);
+ return NULL;
+}
+
+static
+int notification_thread_client_subscribe(struct notification_client *client,
+ struct lttng_condition *condition,
+ struct notification_thread_state *state,
+ enum lttng_notification_channel_status *_status)
+{
+ int ret = 0;
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *node;
+ struct notification_client_list *client_list;
+ struct lttng_condition_list_element *condition_list_element = NULL;
+ struct notification_client_list_element *client_list_element = NULL;
+ enum lttng_notification_channel_status status =
+ LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
+
+ /*
+ * Ensure that the client has not already subscribed to this condition
+ * before.
+ */
+ cds_list_for_each_entry(condition_list_element, &client->condition_list, node) {
+ if (lttng_condition_is_equal(condition_list_element->condition,
+ condition)) {
+ status = LTTNG_NOTIFICATION_CHANNEL_STATUS_ALREADY_SUBSCRIBED;
+ goto end;
+ }
+ }
+
+ condition_list_element = zmalloc(sizeof(*condition_list_element));
+ if (!condition_list_element) {
+ ret = -1;
+ goto error;
+ }
+ client_list_element = zmalloc(sizeof(*client_list_element));
+ if (!client_list_element) {
+ ret = -1;
+ goto error;
+ }
+
+ rcu_read_lock();
+
+ /*
+ * Add the newly-subscribed condition to the client's subscription list.
+ */
+ CDS_INIT_LIST_HEAD(&condition_list_element->node);
+ condition_list_element->condition = condition;
+ cds_list_add(&condition_list_element->node, &client->condition_list);
+
+ /*
+ * Add the client to the list of clients interested in a given trigger
+ * if a "notification" trigger with a corresponding condition was
+ * added prior.
+ */
+ 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) {
+ goto end_unlock;
+ }
+
+ client_list = caa_container_of(node, struct notification_client_list,
+ notification_trigger_ht_node);
+ client_list_element->client = client;
+ CDS_INIT_LIST_HEAD(&client_list_element->node);
+ cds_list_add(&client_list_element->node, &client_list->list);
+end_unlock:
+ rcu_read_unlock();
+end:
+ if (_status) {
+ *_status = status;
+ }
+ return ret;
+error:
+ free(condition_list_element);
+ free(client_list_element);
+ return ret;
+}
+
+static
+int notification_thread_client_unsubscribe(
+ struct notification_client *client,
+ struct lttng_condition *condition,
+ struct notification_thread_state *state,
+ enum lttng_notification_channel_status *_status)
+{
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *node;
+ struct notification_client_list *client_list;
+ struct lttng_condition_list_element *condition_list_element,
+ *condition_tmp;
+ struct notification_client_list_element *client_list_element,
+ *client_tmp;
+ bool condition_found = false;
+ enum lttng_notification_channel_status status =
+ LTTNG_NOTIFICATION_CHANNEL_STATUS_OK;
+
+ /* Remove the condition from the client's condition list. */
+ cds_list_for_each_entry_safe(condition_list_element, condition_tmp,
+ &client->condition_list, node) {
+ if (!lttng_condition_is_equal(condition_list_element->condition,
+ condition)) {
+ continue;
+ }
+
+ cds_list_del(&condition_list_element->node);
+ /*
+ * The caller may be iterating on the client's conditions to
+ * tear down a client's connection. In this case, the condition
+ * will be destroyed at the end.
+ */
+ if (condition != condition_list_element->condition) {
+ lttng_condition_destroy(
+ condition_list_element->condition);
+ }
+ free(condition_list_element);
+ condition_found = true;
+ break;
+ }
+
+ if (!condition_found) {
+ status = LTTNG_NOTIFICATION_CHANNEL_STATUS_UNKNOWN_CONDITION;
+ goto end;
+ }
+
+ /*
+ * Remove the client from the list of clients interested the trigger
+ * matching the condition.
+ */
+ 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) {
+ goto end_unlock;
+ }
+
+ client_list = caa_container_of(node, struct notification_client_list,
+ notification_trigger_ht_node);
+ cds_list_for_each_entry_safe(client_list_element, client_tmp,
+ &client_list->list, node) {
+ if (client_list_element->client->socket != client->socket) {
+ continue;
+ }
+ cds_list_del(&client_list_element->node);
+ free(client_list_element);
+ break;
+ }
+end_unlock:
+ rcu_read_unlock();
+end:
+ lttng_condition_destroy(condition);
+ if (_status) {
+ *_status = status;
+ }
+ return 0;
+}
+
+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);
+ }
+
+ if (client->socket >= 0) {
+ (void) lttcomm_close_unix_sock(client->socket);
+ }
+ lttng_dynamic_buffer_reset(&client->communication.inbound.buffer);
+ lttng_dynamic_buffer_reset(&client->communication.outbound.buffer);
+ free(client);
+}
+
+/*
+ * Call with rcu_read_lock held (and hold for the lifetime of the returned
+ * client pointer).
+ */
+static
+struct notification_client *get_client_from_socket(int socket,
+ struct notification_thread_state *state)
+{
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *node;
+ struct notification_client *client = NULL;
+
+ cds_lfht_lookup(state->client_socket_ht,
+ hash_key_ulong((void *) (unsigned long) socket, lttng_ht_seed),
+ match_client,
+ (void *) (unsigned long) socket,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (!node) {
+ goto end;
+ }
+
+ client = caa_container_of(node, struct notification_client,
+ client_socket_ht_node);
+end:
+ return client;
+}
+
+static
+bool trigger_applies_to_channel(struct lttng_trigger *trigger,
+ struct channel_info *info)
+{
+ enum lttng_condition_status status;
+ struct lttng_condition *condition;
+ const char *trigger_session_name = NULL;
+ const char *trigger_channel_name = NULL;
+ enum lttng_domain_type trigger_domain;
+
+ condition = lttng_trigger_get_condition(trigger);
+ if (!condition) {
+ goto fail;
+ }
+
+ switch (lttng_condition_get_type(condition)) {
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW:
+ case LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH:
+ break;
+ default:
+ goto fail;
+ }
+
+ status = lttng_condition_buffer_usage_get_domain_type(condition,
+ &trigger_domain);
+ assert(status == LTTNG_CONDITION_STATUS_OK);
+ if (info->key.domain != trigger_domain) {
+ goto fail;
+ }
+
+ status = lttng_condition_buffer_usage_get_session_name(
+ condition, &trigger_session_name);
+ assert((status == LTTNG_CONDITION_STATUS_OK) && trigger_session_name);
+
+ status = lttng_condition_buffer_usage_get_channel_name(
+ condition, &trigger_channel_name);
+ assert((status == LTTNG_CONDITION_STATUS_OK) && trigger_channel_name);
+
+ if (strcmp(info->session_name, trigger_session_name)) {
+ goto fail;
+ }
+ if (strcmp(info->channel_name, trigger_channel_name)) {
+ goto fail;
+ }
+
+ return true;
+fail:
+ return false;
+}
+
+static
+bool trigger_applies_to_client(struct lttng_trigger *trigger,
+ struct notification_client *client)
+{
+ bool applies = false;
+ struct lttng_condition_list_element *condition_list_element;
+
+ cds_list_for_each_entry(condition_list_element, &client->condition_list,
+ node) {
+ applies = lttng_condition_is_equal(
+ condition_list_element->condition,
+ lttng_trigger_get_condition(trigger));
+ if (applies) {
+ break;
+ }
+ }
+ return applies;
+}
+
+static
+unsigned long hash_channel_key(struct channel_key *key)
+{
+ return hash_key_u64(&key->key, lttng_ht_seed) ^ hash_key_ulong(
+ (void *) (unsigned long) key->domain, lttng_ht_seed);
+}
+
+static
+int handle_notification_thread_command_add_channel(
+ struct notification_thread_state *state,
+ struct channel_info *channel_info,
+ enum lttng_error_code *cmd_result)
+{
+ struct cds_list_head trigger_list;
+ struct channel_info *new_channel_info;
+ struct channel_key *channel_key;
+ struct lttng_channel_trigger_list *channel_trigger_list = NULL;
+ struct lttng_trigger_ht_element *trigger_ht_element = NULL;
+ int trigger_count = 0;
+ struct cds_lfht_iter iter;
+
+ DBG("[notification-thread] Adding channel %s from session %s, channel key = %" PRIu64 " in %s domain",
+ channel_info->channel_name, channel_info->session_name,
+ channel_info->key.key, channel_info->key.domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
+
+ CDS_INIT_LIST_HEAD(&trigger_list);
+
+ new_channel_info = channel_info_copy(channel_info);
+ if (!new_channel_info) {
+ goto error;
+ }
+
+ channel_key = &new_channel_info->key;
+
+ /* Build a list of all triggers applying to the new channel. */
+ cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
+ node) {
+ struct lttng_trigger_list_element *new_element;
+
+ if (!trigger_applies_to_channel(trigger_ht_element->trigger,
+ channel_info)) {
+ continue;
+ }
+
+ new_element = zmalloc(sizeof(*new_element));
+ if (!new_element) {
+ goto error;
+ }
+ CDS_INIT_LIST_HEAD(&new_element->node);
+ new_element->trigger = trigger_ht_element->trigger;
+ cds_list_add(&new_element->node, &trigger_list);
+ trigger_count++;
+ }
+
+ DBG("[notification-thread] Found %i triggers that apply to newly added channel",
+ trigger_count);
+ channel_trigger_list = zmalloc(sizeof(*channel_trigger_list));
+ if (!channel_trigger_list) {
+ goto error;
+ }
+ channel_trigger_list->channel_key = *channel_key;
+ CDS_INIT_LIST_HEAD(&channel_trigger_list->list);
+ cds_lfht_node_init(&channel_trigger_list->channel_triggers_ht_node);
+ cds_list_splice(&trigger_list, &channel_trigger_list->list);
+
+ rcu_read_lock();
+ /* Add channel to the channel_ht which owns the channel_infos. */
+ cds_lfht_add(state->channels_ht,
+ hash_channel_key(channel_key),
+ &new_channel_info->channels_ht_node);
+ /*
+ * Add the list of triggers associated with this channel to the
+ * channel_triggers_ht.
+ */
+ cds_lfht_add(state->channel_triggers_ht,
+ hash_channel_key(channel_key),
+ &channel_trigger_list->channel_triggers_ht_node);
+ rcu_read_unlock();
+ *cmd_result = LTTNG_OK;
+ return 0;
+error:
+ /* Empty trigger list */
+ channel_info_destroy(new_channel_info);
+ return 1;
+}
+
+static
+int handle_notification_thread_command_remove_channel(
+ struct notification_thread_state *state,
+ uint64_t channel_key, enum lttng_domain_type domain,
+ enum lttng_error_code *cmd_result)
+{
+ struct cds_lfht_node *node;
+ struct cds_lfht_iter iter;
+ struct lttng_channel_trigger_list *trigger_list;
+ struct lttng_trigger_list_element *trigger_list_element, *tmp;
+ struct channel_key key = { .key = channel_key, .domain = domain };
+ struct channel_info *channel_info;
+
+ DBG("[notification-thread] Removing channel key = %" PRIu64 " in %s domain",
+ channel_key, domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
+
+ rcu_read_lock();
+
+ cds_lfht_lookup(state->channel_triggers_ht,
+ hash_channel_key(&key),
+ match_channel_trigger_list,
+ &key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ /*
+ * There is a severe internal error if we are being asked to remove a
+ * channel that doesn't exist.
+ */
+ if (!node) {
+ ERR("[notification-thread] Channel being removed is unknown to the notification thread");
+ goto end;
+ }
+
+ /* Free the list of triggers associated with this channel. */
+ trigger_list = caa_container_of(node, struct lttng_channel_trigger_list,
+ channel_triggers_ht_node);
+ cds_list_for_each_entry_safe(trigger_list_element, tmp,
+ &trigger_list->list, node) {
+ cds_list_del(&trigger_list_element->node);
+ free(trigger_list_element);
+ }
+ cds_lfht_del(state->channel_triggers_ht, node);
+ free(trigger_list);
+
+ /* Free sampled channel state. */
+ cds_lfht_lookup(state->channel_state_ht,
+ hash_channel_key(&key),
+ match_channel_state_sample,
+ &key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ /*
+ * This is expected to be NULL if the channel is destroyed before we
+ * received a sample.
+ */
+ if (node) {
+ struct channel_state_sample *sample = caa_container_of(node,
+ struct channel_state_sample,
+ channel_state_ht_node);
+
+ cds_lfht_del(state->channel_state_ht, node);
+ free(sample);
+ }
+
+ /* Remove the channel from the channels_ht and free it. */
+ cds_lfht_lookup(state->channels_ht,
+ hash_channel_key(&key),
+ match_channel_info,
+ &key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ assert(node);
+ channel_info = caa_container_of(node, struct channel_info,
+ channels_ht_node);
+ cds_lfht_del(state->channels_ht, node);
+ channel_info_destroy(channel_info);
+end:
+ rcu_read_unlock();
+ *cmd_result = LTTNG_OK;
+ return 0;
+}
+
+/*
+ * FIXME A client's credentials are not checked when registering a trigger, nor
+ * are they stored alongside with the trigger.
+ *
+ * The effects of this are benign:
+ * - The client will succeed in registering the trigger, as it is valid,
+ * - The trigger will, internally, be bound to the channel,
+ * - The notifications will not be sent since the client's credentials
+ * are checked against the channel at that moment.
+ */
+static
+int handle_notification_thread_command_register_trigger(
+ struct notification_thread_state *state,
+ struct lttng_trigger *trigger,
+ enum lttng_error_code *cmd_result)
+{
+ int ret = 0;
+ struct lttng_condition *condition;
+ struct notification_client *client;
+ struct notification_client_list *client_list = NULL;
+ struct lttng_trigger_ht_element *trigger_ht_element = NULL;
+ struct notification_client_list_element *client_list_element, *tmp;
+ struct cds_lfht_node *node;
+ struct cds_lfht_iter iter;
+ struct channel_info *channel;
+ bool free_trigger = true;
+
+ rcu_read_lock();
+
+ condition = lttng_trigger_get_condition(trigger);
+ trigger_ht_element = zmalloc(sizeof(*trigger_ht_element));
+ if (!trigger_ht_element) {
+ ret = -1;
+ goto error;
+ }
+
+ /* Add trigger to the trigger_ht. */
+ cds_lfht_node_init(&trigger_ht_element->node);
+ trigger_ht_element->trigger = trigger;
+
+ node = cds_lfht_add_unique(state->triggers_ht,
+ lttng_condition_hash(condition),
+ match_condition,
+ condition,
+ &trigger_ht_element->node);
+ if (node != &trigger_ht_element->node) {
+ /* Not a fatal error, simply report it to the client. */
+ *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.
+ */
+ trigger_ht_element = NULL;
+ free_trigger = false;
+
+ /*
+ * The rest only applies to triggers that have a "notify" action.
+ * It is not skipped as this is the only action type currently
+ * supported.
+ */
+ client_list = zmalloc(sizeof(*client_list));
+ 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,
+ client_socket_ht_node) {
+ if (!trigger_applies_to_client(trigger, client)) {
+ continue;
+ }
+
+ client_list_element = zmalloc(sizeof(*client_list_element));
+ if (!client_list_element) {
+ ret = -1;
+ goto error_free_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);
+ /*
+ * Client list ownership transferred to the
+ * notification_trigger_clients_ht.
+ */
+ client_list = NULL;
+
+ /*
+ * Add the trigger to list of triggers bound to the channels currently
+ * known.
+ */
+ cds_lfht_for_each_entry(state->channels_ht, &iter, channel,
+ channels_ht_node) {
+ struct lttng_trigger_list_element *trigger_list_element;
+ struct lttng_channel_trigger_list *trigger_list;
+
+ if (!trigger_applies_to_channel(trigger, channel)) {
+ continue;
+ }
+
+ cds_lfht_lookup(state->channel_triggers_ht,
+ hash_channel_key(&channel->key),
+ match_channel_trigger_list,
+ &channel->key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ assert(node);
+ /* Free the list of triggers associated with this channel. */
+ trigger_list = caa_container_of(node,
+ struct lttng_channel_trigger_list,
+ channel_triggers_ht_node);
+
+ trigger_list_element = zmalloc(sizeof(*trigger_list_element));
+ if (!trigger_list_element) {
+ ret = -1;
+ goto error_free_client_list;
+ }
+ CDS_INIT_LIST_HEAD(&trigger_list_element->node);
+ trigger_list_element->trigger = trigger;
+ cds_list_add(&trigger_list_element->node, &trigger_list->list);
+ /* A trigger can only apply to one channel. */
+ break;
+ }
+
+ *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_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;
+}
+
+int handle_notification_thread_command_unregister_trigger(
+ struct notification_thread_state *state,
+ struct lttng_trigger *trigger,
+ enum lttng_error_code *_cmd_reply)
+{
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *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();
+
+ cds_lfht_lookup(state->triggers_ht,
+ lttng_condition_hash(condition),
+ match_condition,
+ condition,
+ &iter);
+ triggers_ht_node = cds_lfht_iter_get_node(&iter);
+ if (!triggers_ht_node) {
+ cmd_reply = LTTNG_ERR_TRIGGER_NOT_FOUND;
+ goto end;
+ } else {
+ cmd_reply = LTTNG_OK;
+ }
+
+ /* Remove trigger from channel_triggers_ht. */
+ cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, trigger_list,
+ channel_triggers_ht_node) {
+ struct lttng_trigger_list_element *trigger_element, *tmp;
+
+ cds_list_for_each_entry_safe(trigger_element, tmp,
+ &trigger_list->list, node) {
+ struct lttng_condition *current_condition =
+ lttng_trigger_get_condition(
+ trigger_element->trigger);
+
+ assert(current_condition);
+ if (!lttng_condition_is_equal(condition,
+ current_condition)) {
+ continue;
+ }
+
+ DBG("[notification-thread] Removed trigger from channel_triggers_ht");
+ cds_list_del(&trigger_element->node);
+ }
+ }
+
+ /*
+ * Remove and release the client list from
+ * notification_trigger_clients_ht.
+ */
+ cds_lfht_lookup(state->notification_trigger_clients_ht,
+ lttng_condition_hash(condition),
+ match_client_list,
+ trigger,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ assert(node);
+ client_list = caa_container_of(node, struct notification_client_list,
+ notification_trigger_ht_node);
+ 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, node);
+ free(client_list);
+
+ /* 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);
+ lttng_trigger_destroy(trigger_ht_element->trigger);
+ free(trigger_ht_element);
+end:
+ rcu_read_unlock();
+ if (_cmd_reply) {
+ *_cmd_reply = cmd_reply;
+ }
+ return 0;
+}
+
+/* Returns 0 on success, 1 on exit requested, negative value on error. */
+int handle_notification_thread_command(
+ struct notification_thread_handle *handle,
+ struct notification_thread_state *state)
+{
+ int ret;
+ uint64_t counter;
+ struct notification_thread_command *cmd;
+
+ /* Read event_fd to put it back into a quiescent state. */
+ ret = read(handle->cmd_queue.event_fd, &counter, sizeof(counter));
+ if (ret == -1) {
+ goto error;
+ }
+
+ pthread_mutex_lock(&handle->cmd_queue.lock);
+ cmd = cds_list_first_entry(&handle->cmd_queue.list,
+ struct notification_thread_command, cmd_list_node);
+ switch (cmd->type) {
+ case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
+ DBG("[notification-thread] Received register trigger command");
+ ret = handle_notification_thread_command_register_trigger(
+ state, cmd->parameters.trigger,
+ &cmd->reply_code);
+ break;
+ case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
+ DBG("[notification-thread] Received unregister trigger command");
+ ret = handle_notification_thread_command_unregister_trigger(
+ state, cmd->parameters.trigger,
+ &cmd->reply_code);
+ break;
+ case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
+ DBG("[notification-thread] Received add channel command");
+ ret = handle_notification_thread_command_add_channel(
+ state, &cmd->parameters.add_channel,
+ &cmd->reply_code);
+ break;
+ case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
+ DBG("[notification-thread] Received remove channel command");
+ ret = handle_notification_thread_command_remove_channel(
+ state, cmd->parameters.remove_channel.key,
+ cmd->parameters.remove_channel.domain,
+ &cmd->reply_code);
+ break;
+ case NOTIFICATION_COMMAND_TYPE_QUIT:
+ DBG("[notification-thread] Received quit command");
+ cmd->reply_code = LTTNG_OK;
+ ret = 1;
+ goto end;
+ default:
+ ERR("[notification-thread] Unknown internal command received");
+ goto error_unlock;
+ }
+
+ if (ret) {
+ goto error_unlock;
+ }
+end:
+ cds_list_del(&cmd->cmd_list_node);
+ futex_nto1_wake(&cmd->reply_futex);
+ pthread_mutex_unlock(&handle->cmd_queue.lock);
+ return ret;
+error_unlock:
+ /* Wake-up and return a fatal error to the calling thread. */
+ futex_nto1_wake(&cmd->reply_futex);
+ pthread_mutex_unlock(&handle->cmd_queue.lock);
+ cmd->reply_code = LTTNG_ERR_FATAL;
+error:
+ /* Indicate a fatal error to the caller. */
+ 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)
+{
+ int ret, flags;
+
+ /* Set the pipe as non-blocking. */
+ ret = fcntl(socket, F_GETFL, 0);
+ if (ret == -1) {
+ PERROR("fcntl get socket flags");
+ goto end;
+ }
+ flags = ret;
+
+ ret = fcntl(socket, F_SETFL, flags | O_NONBLOCK);
+ if (ret == -1) {
+ PERROR("fcntl set O_NONBLOCK socket flag");
+ goto end;
+ }
+ DBG("Client socket (fd = %i) set as non-blocking", socket);
+end:
+ return ret;
+}
+
+static
+void client_reset_inbound_state(struct notification_client *client)
+{
+ int ret;
+
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.inbound.buffer, 0);
+ assert(!ret);
+
+ client->communication.inbound.bytes_to_receive =
+ sizeof(struct lttng_notification_channel_message);
+ client->communication.inbound.msg_type =
+ LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN;
+ client->communication.inbound.receive_creds = false;
+ LTTNG_SOCK_SET_UID_CRED(&client->communication.inbound.creds, -1);
+ LTTNG_SOCK_SET_GID_CRED(&client->communication.inbound.creds, -1);
+}
+
+int handle_notification_thread_client_connect(
+ struct notification_thread_state *state)
+{
+ int ret;
+ struct notification_client *client;
+
+ DBG("[notification-thread] Handling new notification channel client connection");
+
+ client = zmalloc(sizeof(*client));
+ if (!client) {
+ /* Fatal error. */
+ ret = -1;
+ goto error;
+ }
+ CDS_INIT_LIST_HEAD(&client->condition_list);
+ lttng_dynamic_buffer_init(&client->communication.inbound.buffer);
+ lttng_dynamic_buffer_init(&client->communication.outbound.buffer);
+ client_reset_inbound_state(client);
+
+ ret = lttcomm_accept_unix_sock(state->notification_channel_socket);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to accept new notification channel client connection");
+ ret = 0;
+ goto error;
+ }
+
+ client->socket = ret;
+
+ ret = socket_set_non_blocking(client->socket);
+ if (ret) {
+ ERR("[notification-thread] Failed to set new notification channel client connection socket as non-blocking");
+ goto error;
+ }
+
+ ret = lttcomm_setsockopt_creds_unix_sock(client->socket);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to set socket options on new notification channel client socket");
+ ret = 0;
+ goto error;
+ }
+
+ ret = lttng_poll_add(&state->events, client->socket,
+ LPOLLIN | LPOLLERR |
+ LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add notification channel client socket to poll set");
+ ret = 0;
+ goto error;
+ }
+ DBG("[notification-thread] Added new notification channel client socket (%i) to poll set",
+ client->socket);
+
+ /* Add to ht. */
+ rcu_read_lock();
+ cds_lfht_add(state->client_socket_ht,
+ hash_client_socket(client->socket),
+ &client->client_socket_ht_node);
+ rcu_read_unlock();
+
+ return ret;
+error:
+ 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;
+
+ rcu_read_lock();
+ DBG("[notification-thread] Closing client connection (socket fd = %i)",
+ client_socket);
+ client = get_client_from_socket(client_socket, state);
+ if (!client) {
+ /* Internal state corruption, fatal error. */
+ ERR("[notification-thread] Unable to find client (socket fd = %i)",
+ client_socket);
+ ret = -1;
+ 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);
+end:
+ rcu_read_unlock();
+ return ret;
+}
+
+int handle_notification_thread_client_disconnect_all(
+ struct notification_thread_state *state)
+{
+ struct cds_lfht_iter iter;
+ struct notification_client *client;
+ bool error_encoutered = false;
+
+ 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) {
+ int ret;
+
+ ret = handle_notification_thread_client_disconnect(
+ client->socket, state);
+ if (ret) {
+ error_encoutered = true;
+ }
+ }
+ rcu_read_unlock();
+ return error_encoutered ? 1 : 0;
+}
+
+int handle_notification_thread_trigger_unregister_all(
+ struct notification_thread_state *state)
+{
+ bool error_occured = false;
+ struct cds_lfht_iter iter;
+ struct lttng_trigger_ht_element *trigger_ht_element;
+
+ cds_lfht_for_each_entry(state->triggers_ht, &iter, trigger_ht_element,
+ node) {
+ int ret = handle_notification_thread_command_unregister_trigger(
+ state, trigger_ht_element->trigger, NULL);
+ if (ret) {
+ error_occured = true;
+ }
+ }
+ return error_occured ? -1 : 0;
+}
+
+static
+int client_flush_outgoing_queue(struct notification_client *client,
+ struct notification_thread_state *state)
+{
+ ssize_t ret;
+ size_t to_send_count;
+
+ assert(client->communication.outbound.buffer.size != 0);
+ to_send_count = client->communication.outbound.buffer.size;
+ DBG("[notification-thread] Flushing client (socket fd = %i) outgoing queue",
+ client->socket);
+
+ 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)) {
+ DBG("[notification-thread] Client (socket fd = %i) outgoing queue could not be completely flushed",
+ client->socket);
+ to_send_count -= max(ret, 0);
+
+ memcpy(client->communication.outbound.buffer.data,
+ client->communication.outbound.buffer.data +
+ client->communication.outbound.buffer.size - to_send_count,
+ to_send_count);
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.outbound.buffer,
+ to_send_count);
+ if (ret) {
+ 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;
+ }
+ } else if (ret < 0) {
+ /* Generic error, disconnect the client. */
+ ERR("[notification-thread] Failed to send flush outgoing queue, disconnecting client (socket fd = %i)",
+ client->socket);
+ ret = handle_notification_thread_client_disconnect(
+ client->socket, state);
+ if (ret) {
+ goto error;
+ }
+ } else {
+ /* No error and flushed the queue completely. */
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.outbound.buffer, 0);
+ if (ret) {
+ goto error;
+ }
+ ret = lttng_poll_mod(&state->events, client->socket,
+ CLIENT_POLL_MASK_IN);
+ if (ret) {
+ goto error;
+ }
+
+ client->communication.outbound.queued_command_reply = false;
+ client->communication.outbound.dropped_notification = false;
+ }
+
+ return 0;
+error:
+ return -1;
+}
+
+static
+int client_send_command_reply(struct notification_client *client,
+ struct notification_thread_state *state,
+ enum lttng_notification_channel_status status)
+{
+ int ret;
+ struct lttng_notification_channel_command_reply reply = {
+ .status = (int8_t) status,
+ };
+ struct lttng_notification_channel_message msg = {
+ .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_COMMAND_REPLY,
+ .size = sizeof(reply),
+ };
+ char buffer[sizeof(msg) + sizeof(reply)];
+
+ if (client->communication.outbound.queued_command_reply) {
+ /* Protocol error. */
+ goto error;
+ }
+
+ memcpy(buffer, &msg, sizeof(msg));
+ memcpy(buffer + sizeof(msg), &reply, sizeof(reply));
+ DBG("[notification-thread] Send command reply (%i)", (int) status);
+
+ /* Enqueue buffer to outgoing queue and flush it. */
+ ret = lttng_dynamic_buffer_append(
+ &client->communication.outbound.buffer,
+ buffer, sizeof(buffer));
+ if (ret) {
+ goto error;
+ }
+
+ ret = client_flush_outgoing_queue(client, state);
+ if (ret) {
+ goto error;
+ }
+
+ if (client->communication.outbound.buffer.size != 0) {
+ /* Queue could not be emptied. */
+ client->communication.outbound.queued_command_reply = true;
+ }
+
+ return 0;
+error:
+ return -1;
+}
+
+static
+int client_dispatch_message(struct notification_client *client,
+ struct notification_thread_state *state)
+{
+ int ret = 0;
+
+ if (client->communication.inbound.msg_type !=
+ LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE &&
+ client->communication.inbound.msg_type !=
+ LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_UNKNOWN &&
+ !client->validated) {
+ WARN("[notification-thread] client attempted a command before handshake");
+ ret = -1;
+ goto end;
+ }
+
+ 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;
+ if (client->communication.inbound.msg_type ==
+ LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_HANDSHAKE) {
+ client->communication.inbound.receive_creds = true;
+ }
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.inbound.buffer, 0);
+ if (ret) {
+ goto end;
+ }
+ 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. */
+ client_reset_inbound_state(client);
+ client->validated = true;
+ 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) {
+ /*
+ * FIXME The current state should be evaluated on
+ * subscription.
+ */
+ 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. */
+ client_reset_inbound_state(client);
+ break;
+ }
+ default:
+ abort();
+ }
+end:
+ return ret;
+}
+
+/* Incoming data from client. */
+int handle_notification_thread_client_in(
+ struct notification_thread_state *state, int socket)
+{
+ int ret;
+ struct notification_client *client;
+ ssize_t recv_ret;
+ size_t offset;
+
+ client = get_client_from_socket(socket, state);
+ if (!client) {
+ /* Internal error, abort. */
+ ret = -1;
+ goto end;
+ }
+
+ offset = client->communication.inbound.buffer.size;
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.inbound.buffer,
+ client->communication.inbound.bytes_to_receive);
+ if (ret) {
+ goto end;
+ }
+
+ if (client->communication.inbound.receive_creds) {
+ recv_ret = lttcomm_recv_creds_unix_sock(socket,
+ client->communication.inbound.buffer.data + offset,
+ client->communication.inbound.bytes_to_receive,
+ &client->communication.inbound.creds);
+ if (recv_ret > 0) {
+ client->communication.inbound.receive_creds = false;
+ client->communication.inbound.creds_received = true;
+ }
+ } else {
+ recv_ret = lttcomm_recv_unix_sock_non_block(socket,
+ client->communication.inbound.buffer.data + offset,
+ client->communication.inbound.bytes_to_receive);
+ }
+ if (recv_ret < 0) {
+ goto error_disconnect_client;
+ }
+
+ client->communication.inbound.bytes_to_receive -= recv_ret;
+ ret = lttng_dynamic_buffer_set_size(
+ &client->communication.inbound.buffer,
+ client->communication.inbound.buffer.size -
+ client->communication.inbound.bytes_to_receive);
+ if (ret) {
+ goto end;
+ }
+
+ if (client->communication.inbound.bytes_to_receive == 0) {
+ ret = client_dispatch_message(client, state);
+ if (ret) {
+ /*
+ * Only returns an error if this client must be
+ * disconnected.
+ */
+ goto error_disconnect_client;
+ }
+ } else {
+ goto end;
+ }
+end:
+ return ret;
+error_disconnect_client:
+ ret = handle_notification_thread_client_disconnect(socket, state);
+ return ret;
+}
+
+/* Client ready to receive outgoing data. */
+int handle_notification_thread_client_out(
+ struct notification_thread_state *state, int socket)
+{
+ int ret;
+ struct notification_client *client;
+
+ client = get_client_from_socket(socket, state);
+ if (!client) {
+ /* Internal error, abort. */
+ ret = -1;
+ goto end;
+ }
+
+ ret = client_flush_outgoing_queue(client, state);
+ if (ret) {
+ goto end;
+ }
+end:
+ return ret;
+}
+
+static
+bool evaluate_buffer_usage_condition(struct lttng_condition *condition,
+ struct channel_state_sample *sample, uint64_t buffer_capacity)
+{
+ bool result = false;
+ uint64_t threshold;
+ enum lttng_condition_type condition_type;
+ struct lttng_condition_buffer_usage *use_condition = container_of(
+ condition, struct lttng_condition_buffer_usage,
+ parent);
+
+ if (!sample) {
+ goto end;
+ }
+
+ if (use_condition->threshold_bytes.set) {
+ threshold = use_condition->threshold_bytes.value;
+ } else {
+ /*
+ * Threshold was expressed as a ratio.
+ *
+ * TODO the threshold (in bytes) of conditions expressed
+ * as a ratio of total buffer size could be cached to
+ * forego this double-multiplication or it could be performed
+ * as fixed-point math.
+ *
+ * Note that caching should accomodate the case where the
+ * condition applies to multiple channels (i.e. don't assume
+ * that all channels matching my_chann* have the same size...)
+ */
+ threshold = (uint64_t) (use_condition->threshold_ratio.value *
+ (double) buffer_capacity);
+ }
+
+ condition_type = lttng_condition_get_type(condition);
+ if (condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW) {
+ DBG("[notification-thread] Low buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
+ threshold, sample->highest_usage);
+
+ /*
+ * The low condition should only be triggered once _all_ of the
+ * streams in a channel have gone below the "low" threshold.
+ */
+ if (sample->highest_usage <= threshold) {
+ result = true;
+ }
+ } else {
+ DBG("[notification-thread] High buffer usage condition being evaluated: threshold = %" PRIu64 ", highest usage = %" PRIu64,
+ threshold, sample->highest_usage);
+
+ /*
+ * For high buffer usage scenarios, we want to trigger whenever
+ * _any_ of the streams has reached the "high" threshold.
+ */
+ if (sample->highest_usage >= threshold) {
+ result = true;
+ }
+ }
+end:
+ return result;
+}
+
+static
+int evaluate_condition(struct lttng_condition *condition,
+ struct lttng_evaluation **evaluation,
+ struct notification_thread_state *state,
+ struct channel_state_sample *previous_sample,
+ struct channel_state_sample *latest_sample,
+ uint64_t buffer_capacity)
+{
+ int ret = 0;
+ enum lttng_condition_type condition_type;
+ bool previous_sample_result;
+ bool latest_sample_result;
+
+ condition_type = lttng_condition_get_type(condition);
+ /* No other condition type supported for the moment. */
+ assert(condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_LOW ||
+ condition_type == LTTNG_CONDITION_TYPE_BUFFER_USAGE_HIGH);
+
+ previous_sample_result = evaluate_buffer_usage_condition(condition,
+ previous_sample, buffer_capacity);
+ latest_sample_result = evaluate_buffer_usage_condition(condition,
+ latest_sample, buffer_capacity);
+
+ if (!latest_sample_result ||
+ (previous_sample_result == latest_sample_result)) {
+ /*
+ * Only trigger on a condition evaluation transition.
+ *
+ * NOTE: This edge-triggered logic may not be appropriate for
+ * future condition types.
+ */
+ goto end;
+ }
+
+ if (evaluation && latest_sample_result) {
+ *evaluation = lttng_evaluation_buffer_usage_create(
+ condition_type,
+ latest_sample->highest_usage,
+ buffer_capacity);
+ if (!*evaluation) {
+ ret = -1;
+ goto end;
+ }
+ }
+end:
+ return ret;
+}
+
+static
+int client_enqueue_dropped_notification(struct notification_client *client,
+ struct notification_thread_state *state)
+{
+ int ret;
+ struct lttng_notification_channel_message msg = {
+ .type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION_DROPPED,
+ .size = 0,
+ };
+
+ ret = lttng_dynamic_buffer_append(
+ &client->communication.outbound.buffer, &msg,
+ sizeof(msg));
+ return ret;
+}
+
+static
+int send_evaluation_to_clients(struct lttng_trigger *trigger,
+ struct lttng_evaluation *evaluation,
+ struct notification_client_list* client_list,
+ struct notification_thread_state *state,
+ uid_t channel_uid, gid_t channel_gid)
+{
+ int ret = 0;
+ struct lttng_dynamic_buffer msg_buffer;
+ struct notification_client_list_element *client_list_element, *tmp;
+ struct lttng_notification *notification;
+ struct lttng_condition *condition;
+ ssize_t expected_notification_size, notification_size;
+ struct lttng_notification_channel_message msg;
+
+ lttng_dynamic_buffer_init(&msg_buffer);
+
+ condition = lttng_trigger_get_condition(trigger);
+ assert(condition);
+
+ notification = lttng_notification_create(condition, evaluation);
+ if (!notification) {
+ ret = -1;
+ goto end;
+ }
+
+ expected_notification_size = lttng_notification_serialize(notification,
+ NULL);
+ if (expected_notification_size < 0) {
+ ERR("[notification-thread] Failed to get size of serialized notification");
+ ret = -1;
+ goto end;
+ }
+
+ msg.type = (int8_t) LTTNG_NOTIFICATION_CHANNEL_MESSAGE_TYPE_NOTIFICATION;
+ msg.size = (uint32_t) expected_notification_size;
+ ret = lttng_dynamic_buffer_append(&msg_buffer, &msg, sizeof(msg));
+ if (ret) {
+ goto end;
+ }
+
+ ret = lttng_dynamic_buffer_set_size(&msg_buffer,
+ msg_buffer.size + expected_notification_size);
+ if (ret) {
+ goto end;
+ }
+
+ notification_size = lttng_notification_serialize(notification,
+ msg_buffer.data + sizeof(msg));
+ if (notification_size != expected_notification_size) {
+ ERR("[notification-thread] Failed to serialize notification");
+ ret = -1;
+ goto end;
+ }
+
+ 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 &&
+ 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] Sending notification to client (fd = %i, %zu bytes)",
+ client->socket, msg_buffer.size);
+ if (client->communication.outbound.buffer.size) {
+ /*
+ * Outgoing data is already buffered for this client;
+ * drop the notification and enqueue a "dropped
+ * notification" message if this is the first dropped
+ * notification since the socket spilled-over to the
+ * queue.
+ */
+ DBG("[notification-thread] Dropping notification addressed to client (socket fd = %i)",
+ client->socket);
+ if (!client->communication.outbound.dropped_notification) {
+ client->communication.outbound.dropped_notification = true;
+ ret = client_enqueue_dropped_notification(
+ client, state);
+ if (ret) {
+ goto end;
+ }
+ }
+ continue;
+ }
+
+ ret = lttng_dynamic_buffer_append_buffer(
+ &client->communication.outbound.buffer,
+ &msg_buffer);
+ if (ret) {
+ goto end;
+ }
+
+ ret = client_flush_outgoing_queue(client, state);
+ if (ret) {
+ goto end;
+ }
+ }
+ ret = 0;
+end:
+ lttng_notification_destroy(notification);
+ lttng_dynamic_buffer_reset(&msg_buffer);
+ return ret;
+}
+
+int handle_notification_thread_channel_sample(
+ struct notification_thread_state *state, int pipe,
+ enum lttng_domain_type domain)
+{
+ int ret = 0;
+ struct lttcomm_consumer_channel_monitor_msg sample_msg;
+ struct channel_state_sample previous_sample, latest_sample;
+ struct channel_info *channel_info;
+ struct cds_lfht_node *node;
+ struct cds_lfht_iter iter;
+ struct lttng_channel_trigger_list *trigger_list;
+ struct lttng_trigger_list_element *trigger_list_element;
+ bool previous_sample_available = false;
+
+ /*
+ * The monitoring pipe only holds messages smaller than PIPE_BUF,
+ * ensuring that read/write of sampling messages are atomic.
+ */
+ do {
+ ret = read(pipe, &sample_msg, sizeof(sample_msg));
+ } while (ret == -1 && errno == EINTR);
+ if (ret != sizeof(sample_msg)) {
+ ERR("[notification-thread] Failed to read from monitoring pipe (fd = %i)",
+ pipe);
+ ret = -1;
+ goto end;
+ }
+
+ ret = 0;
+ latest_sample.key.key = sample_msg.key;
+ latest_sample.key.domain = domain;
+ latest_sample.highest_usage = sample_msg.highest;
+ latest_sample.lowest_usage = sample_msg.lowest;
+
+ rcu_read_lock();
+
+ /* Retrieve the channel's informations */
+ cds_lfht_lookup(state->channels_ht,
+ hash_channel_key(&latest_sample.key),
+ match_channel_info,
+ &latest_sample.key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (!node) {
+ /*
+ * Not an error since the consumer can push a sample to the pipe
+ * and the rest of the session daemon could notify us of the
+ * channel's destruction before we get a chance to process that
+ * sample.
+ */
+ DBG("[notification-thread] Received a sample for an unknown channel from consumerd, key = %" PRIu64 " in %s domain",
+ latest_sample.key.key,
+ domain == LTTNG_DOMAIN_KERNEL ? "kernel" :
+ "user space");
+ goto end_unlock;
+ }
+ channel_info = caa_container_of(node, struct channel_info,
+ channels_ht_node);
+ DBG("[notification-thread] Handling channel sample for channel %s (key = %" PRIu64 ") in session %s (highest usage = %" PRIu64 ", lowest usage = %" PRIu64")",
+ channel_info->channel_name,
+ latest_sample.key.key,
+ channel_info->session_name,
+ latest_sample.highest_usage,
+ latest_sample.lowest_usage);
+
+ /* Retrieve the channel's last sample, if it exists, and update it. */
+ cds_lfht_lookup(state->channel_state_ht,
+ hash_channel_key(&latest_sample.key),
+ match_channel_state_sample,
+ &latest_sample.key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (node) {
+ struct channel_state_sample *stored_sample;
+
+ /* Update the sample stored. */
+ stored_sample = caa_container_of(node,
+ struct channel_state_sample,
+ channel_state_ht_node);
+ memcpy(&previous_sample, stored_sample,
+ sizeof(previous_sample));
+ stored_sample->highest_usage = latest_sample.highest_usage;
+ stored_sample->lowest_usage = latest_sample.lowest_usage;
+ previous_sample_available = true;
+ } else {
+ /*
+ * This is the channel's first sample, allocate space for and
+ * store the new sample.
+ */
+ struct channel_state_sample *stored_sample;
+
+ stored_sample = zmalloc(sizeof(*stored_sample));
+ if (!stored_sample) {
+ ret = -1;
+ goto end_unlock;
+ }
+
+ memcpy(stored_sample, &latest_sample, sizeof(*stored_sample));
+ cds_lfht_node_init(&stored_sample->channel_state_ht_node);
+ cds_lfht_add(state->channel_state_ht,
+ hash_channel_key(&stored_sample->key),
+ &stored_sample->channel_state_ht_node);
+ }
+
+ /* Find triggers associated with this channel. */
+ cds_lfht_lookup(state->channel_triggers_ht,
+ hash_channel_key(&latest_sample.key),
+ match_channel_trigger_list,
+ &latest_sample.key,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (!node) {
+ goto end_unlock;
+ }
+
+ 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) {
+ struct lttng_condition *condition;
+ struct lttng_action *action;
+ struct lttng_trigger *trigger;
+ struct notification_client_list *client_list;
+ struct lttng_evaluation *evaluation = NULL;
+
+ trigger = trigger_list_element->trigger;
+ condition = lttng_trigger_get_condition(trigger);
+ assert(condition);
+ action = lttng_trigger_get_action(trigger);
+
+ /* Notify actions are the only type currently supported. */
+ assert(lttng_action_get_type(action) ==
+ LTTNG_ACTION_TYPE_NOTIFY);
+
+ /*
+ * Check if any client is subscribed to the result of this
+ * evaluation.
+ */
+ cds_lfht_lookup(state->notification_trigger_clients_ht,
+ lttng_condition_hash(condition),
+ match_client_list,
+ trigger,
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ assert(node);
+
+ client_list = caa_container_of(node,
+ struct notification_client_list,
+ notification_trigger_ht_node);
+ if (cds_list_empty(&client_list->list)) {
+ /*
+ * No clients interested in the evaluation's result,
+ * skip it.
+ */
+ continue;
+ }
+
+ ret = evaluate_condition(condition, &evaluation, state,
+ previous_sample_available ? &previous_sample : NULL,
+ &latest_sample, channel_info->capacity);
+ if (ret) {
+ goto end_unlock;
+ }
+
+ if (!evaluation) {
+ continue;
+ }
+
+ /* Dispatch evaluation result to all clients. */
+ ret = send_evaluation_to_clients(trigger_list_element->trigger,
+ evaluation, client_list, state,
+ channel_info->uid, channel_info->gid);
+ if (ret) {
+ goto end_unlock;
+ }
+ }
+end_unlock:
+ rcu_read_unlock();
+end:
+ return ret;
+}
--- /dev/null
+/*
+ * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * 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.
+ *
+ * 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
+#include <lttng/trigger/trigger.h>
+#include <lttng/notification/channel-internal.h>
+#include <lttng/notification/notification-internal.h>
+#include <lttng/condition/condition-internal.h>
+#include <lttng/condition/buffer-usage-internal.h>
+#include <common/error.h>
+#include <common/config/session-config.h>
+#include <common/defaults.h>
+#include <common/utils.h>
+#include <common/futex.h>
+#include <common/align.h>
+#include <common/time.h>
+#include <sys/eventfd.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <signal.h>
+
+#include "notification-thread.h"
+#include "notification-thread-events.h"
+#include "notification-thread-commands.h"
+#include "lttng-sessiond.h"
+#include "health-sessiond.h"
+
+#include <urcu.h>
+#include <urcu/list.h>
+#include <urcu/rculfhash.h>
+
+/**
+ * This thread maintains an internal state associating clients and triggers.
+ *
+ * In order to speed-up and simplify queries, hash tables providing the
+ * following associations are maintained:
+ *
+ * - client_socket_ht: associate a client's socket (fd) to its "struct client"
+ * This hash table owns the "struct client" which must thus be
+ * disposed-of on removal from the hash table.
+ *
+ * - channel_triggers_ht:
+ * associates a channel key to a list of
+ * struct lttng_trigger_list_nodes. The triggers in this list are
+ * those that have conditions that apply to this channel.
+ * This hash table owns the list, but not the triggers themselves.
+ *
+ * - channel_state_ht:
+ * associates a pair (channel key, channel domain) to its last
+ * sampled state received from the consumer daemon
+ * (struct channel_state).
+ * This previous sample is kept to implement edge-triggered
+ * conditions as we need to detect the state transitions.
+ * This hash table owns the channel state.
+ *
+ * - notification_trigger_clients_ht:
+ * associates notification-emitting triggers to clients
+ * (struct notification_client_ht_node) subscribed to those
+ * conditions.
+ * The condition's hash and match functions are used directly since
+ * all triggers in this hash table have the "notify" action.
+ * This hash table holds no ownership.
+ *
+ * - channels_ht:
+ * associates a channel_key to a struct channel_info. The hash table
+ * holds the ownership of the struct channel_info.
+ *
+ * - triggers_ht:
+ * associated a condition to a struct lttng_trigger_ht_element.
+ * The hash table holds the ownership of the
+ * lttng_trigger_ht_elements along with the triggers themselves.
+ *
+ * The thread reacts to the following internal events:
+ * 1) creation of a tracing channel,
+ * 2) destruction of a tracing channel,
+ * 3) registration of a trigger,
+ * 4) unregistration of a trigger,
+ * 5) reception of a channel monitor sample from the consumer daemon.
+ *
+ * Events specific to notification-emitting triggers:
+ * 6) connection of a notification client,
+ * 7) disconnection of a notification client,
+ * 8) subscription of a client to a conditions' notifications,
+ * 9) unsubscription of a client from a conditions' notifications,
+ *
+ *
+ * 1) Creation of a tracing channel
+ * - notification_trigger_clients_ht is traversed to identify
+ * triggers which apply to this new channel,
+ * - triggers identified are added to the channel_triggers_ht.
+ * - add channel to channels_ht
+ *
+ * 2) Destruction of a tracing channel
+ * - remove entry from channel_triggers_ht, releasing the list wrapper and
+ * elements,
+ * - remove entry from the channel_state_ht.
+ * - remove channel from channels_ht
+ *
+ * 3) Registration of a trigger
+ * - if the trigger's action is of type "notify",
+ * - traverse the list of conditions of every client to build a list of
+ * clients which have to be notified when this trigger's condition is met,
+ * - add list of clients (even if it is empty) to the
+ * notification_trigger_clients_ht,
+ * - add trigger to channel_triggers_ht (if applicable),
+ * - add trigger to triggers_ht
+ *
+ * 4) Unregistration of a trigger
+ * - if the trigger's action is of type "notify",
+ * - remove the trigger from the notification_trigger_clients_ht,
+ * - remove trigger from channel_triggers_ht (if applicable),
+ * - remove trigger from triggers_ht
+ *
+ * 5) Reception of a channel monitor sample from the consumer daemon
+ * - evaluate the conditions associated with the triggers found in
+ * the channel_triggers_ht,
+ * - if a condition evaluates to "true" and the condition is of type
+ * "notify", query the notification_trigger_clients_ht and send
+ * a notification to the clients.
+ *
+ * 6) Connection of a client
+ * - add client socket to the client_socket_ht.
+ *
+ * 7) Disconnection of a client
+ * - remove client socket from the client_socket_ht,
+ * - traverse all conditions to which the client is subscribed and remove
+ * the client from the notification_trigger_clients_ht.
+ *
+ * 8) Subscription of a client to a condition's notifications
+ * - Add the condition to the client's list of subscribed conditions,
+ * - Look-up notification_trigger_clients_ht and add the client to
+ * list of clients.
+ *
+ * 9) Unsubscription of a client to a condition's notifications
+ * - Remove the condition from the client's list of subscribed conditions,
+ * - Look-up notification_trigger_clients_ht and remove the client
+ * from the list of clients.
+ */
+
+/*
+ * Destroy the thread data previously created by the init function.
+ */
+void notification_thread_handle_destroy(
+ struct notification_thread_handle *handle)
+{
+ int ret;
+ struct notification_thread_command *cmd, *tmp;
+
+ if (!handle) {
+ goto end;
+ }
+
+ if (handle->cmd_queue.event_fd < 0) {
+ goto end;
+ }
+ ret = close(handle->cmd_queue.event_fd);
+ if (ret < 0) {
+ PERROR("close notification command queue event_fd");
+ }
+
+ pthread_mutex_lock(&handle->cmd_queue.lock);
+ /* Purge queue of in-flight commands and mark them as cancelled. */
+ cds_list_for_each_entry_safe(cmd, tmp, &handle->cmd_queue.list,
+ cmd_list_node) {
+ cds_list_del(&cmd->cmd_list_node);
+ cmd->reply_code = LTTNG_ERR_COMMAND_CANCELLED;
+ futex_nto1_wake(&cmd->reply_futex);
+ }
+ pthread_mutex_unlock(&handle->cmd_queue.lock);
+ pthread_mutex_destroy(&handle->cmd_queue.lock);
+
+ if (handle->channel_monitoring_pipes.ust32_consumer >= 0) {
+ ret = close(handle->channel_monitoring_pipes.ust32_consumer);
+ if (ret) {
+ PERROR("close 32-bit consumer channel monitoring pipe");
+ }
+ }
+ if (handle->channel_monitoring_pipes.ust64_consumer >= 0) {
+ ret = close(handle->channel_monitoring_pipes.ust64_consumer);
+ if (ret) {
+ PERROR("close 64-bit consumer channel monitoring pipe");
+ }
+ }
+ if (handle->channel_monitoring_pipes.kernel_consumer >= 0) {
+ ret = close(handle->channel_monitoring_pipes.kernel_consumer);
+ if (ret) {
+ PERROR("close kernel consumer channel monitoring pipe");
+ }
+ }
+end:
+ free(handle);
+}
+
+struct notification_thread_handle *notification_thread_handle_create(
+ struct lttng_pipe *ust32_channel_monitor_pipe,
+ struct lttng_pipe *ust64_channel_monitor_pipe,
+ struct lttng_pipe *kernel_channel_monitor_pipe)
+{
+ int ret;
+ struct notification_thread_handle *handle;
+
+ handle = zmalloc(sizeof(*handle));
+ if (!handle) {
+ goto end;
+ }
+
+ /* FIXME Replace eventfd by a pipe to support older kernels. */
+ handle->cmd_queue.event_fd = eventfd(0, EFD_CLOEXEC);
+ if (handle->cmd_queue.event_fd < 0) {
+ PERROR("eventfd notification command queue");
+ goto error;
+ }
+ CDS_INIT_LIST_HEAD(&handle->cmd_queue.list);
+ ret = pthread_mutex_init(&handle->cmd_queue.lock, NULL);
+ if (ret) {
+ goto error;
+ }
+
+ if (ust32_channel_monitor_pipe) {
+ handle->channel_monitoring_pipes.ust32_consumer =
+ lttng_pipe_release_readfd(
+ ust32_channel_monitor_pipe);
+ if (handle->channel_monitoring_pipes.ust32_consumer < 0) {
+ goto error;
+ }
+ } else {
+ handle->channel_monitoring_pipes.ust32_consumer = -1;
+ }
+ if (ust64_channel_monitor_pipe) {
+ handle->channel_monitoring_pipes.ust64_consumer =
+ lttng_pipe_release_readfd(
+ ust64_channel_monitor_pipe);
+ if (handle->channel_monitoring_pipes.ust64_consumer < 0) {
+ goto error;
+ }
+ } else {
+ handle->channel_monitoring_pipes.ust64_consumer = -1;
+ }
+ if (kernel_channel_monitor_pipe) {
+ handle->channel_monitoring_pipes.kernel_consumer =
+ lttng_pipe_release_readfd(
+ kernel_channel_monitor_pipe);
+ if (handle->channel_monitoring_pipes.kernel_consumer < 0) {
+ goto error;
+ }
+ } else {
+ handle->channel_monitoring_pipes.kernel_consumer = -1;
+ }
+end:
+ return handle;
+error:
+ notification_thread_handle_destroy(handle);
+ return NULL;
+}
+
+static
+char *get_notification_channel_sock_path(void)
+{
+ int ret;
+ bool is_root = !getuid();
+ char *sock_path;
+
+ sock_path = zmalloc(LTTNG_PATH_MAX);
+ if (!sock_path) {
+ goto error;
+ }
+
+ if (is_root) {
+ ret = snprintf(sock_path, LTTNG_PATH_MAX,
+ DEFAULT_GLOBAL_NOTIFICATION_CHANNEL_UNIX_SOCK);
+ if (ret < 0) {
+ goto error;
+ }
+ } else {
+ char *home_path = utils_get_home_dir();
+
+ if (!home_path) {
+ ERR("Can't get HOME directory for socket creation");
+ goto error;
+ }
+
+ ret = snprintf(sock_path, LTTNG_PATH_MAX,
+ DEFAULT_HOME_NOTIFICATION_CHANNEL_UNIX_SOCK,
+ home_path);
+ if (ret < 0) {
+ goto error;
+ }
+ }
+
+ return sock_path;
+error:
+ free(sock_path);
+ return NULL;
+}
+
+static
+void notification_channel_socket_destroy(int fd)
+{
+ int ret;
+ char *sock_path = get_notification_channel_sock_path();
+
+ DBG("[notification-thread] Destroying notification channel socket");
+
+ if (sock_path) {
+ ret = unlink(sock_path);
+ free(sock_path);
+ if (ret < 0) {
+ PERROR("unlink notification channel socket");
+ }
+ }
+
+ ret = close(fd);
+ if (ret) {
+ PERROR("close notification channel socket");
+ }
+}
+
+static
+int notification_channel_socket_create(void)
+{
+ int fd = -1, ret;
+ char *sock_path = get_notification_channel_sock_path();
+
+ DBG("[notification-thread] Creating notification channel UNIX socket at %s",
+ sock_path);
+
+ ret = lttcomm_create_unix_sock(sock_path);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to create notification socket");
+ goto error;
+ }
+ fd = ret;
+
+ ret = chmod(sock_path, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+ if (ret < 0) {
+ ERR("Set file permissions failed: %s", sock_path);
+ PERROR("chmod notification channel socket");
+ goto error;
+ }
+
+ if (getuid() == 0) {
+ ret = chown(sock_path, 0,
+ utils_get_group_id(tracing_group_name));
+ if (ret) {
+ ERR("Failed to set the notification channel socket's group");
+ ret = -1;
+ goto error;
+ }
+ }
+
+ DBG("[notification-thread] Notification channel UNIX socket created (fd = %i)",
+ fd);
+ free(sock_path);
+ return fd;
+error:
+ if (fd >= 0 && close(fd) < 0) {
+ PERROR("close notification channel socket");
+ }
+ free(sock_path);
+ return ret;
+}
+
+static
+int init_poll_set(struct lttng_poll_event *poll_set,
+ struct notification_thread_handle *handle,
+ int notification_channel_socket)
+{
+ int ret;
+
+ /*
+ * Create pollset with size 5:
+ * - notification channel socket (listen for new connections),
+ * - command queue event fd (internal sessiond commands),
+ * - consumerd (32-bit user space) channel monitor pipe,
+ * - consumerd (64-bit user space) channel monitor pipe,
+ * - consumerd (kernel) channel monitor pipe.
+ */
+ ret = lttng_poll_create(poll_set, 5, LTTNG_CLOEXEC);
+ if (ret < 0) {
+ goto end;
+ }
+
+ ret = lttng_poll_add(poll_set, notification_channel_socket,
+ LPOLLIN | LPOLLERR | LPOLLHUP | LPOLLRDHUP);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add notification channel socket to pollset");
+ goto error;
+ }
+ ret = lttng_poll_add(poll_set, handle->cmd_queue.event_fd,
+ LPOLLIN | LPOLLERR);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add notification command queue event fd to pollset");
+ goto error;
+ }
+ ret = lttng_poll_add(poll_set,
+ handle->channel_monitoring_pipes.ust32_consumer,
+ LPOLLIN | LPOLLERR);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add ust-32 channel monitoring pipe fd to pollset");
+ goto error;
+ }
+ ret = lttng_poll_add(poll_set,
+ handle->channel_monitoring_pipes.ust64_consumer,
+ LPOLLIN | LPOLLERR);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add ust-64 channel monitoring pipe fd to pollset");
+ goto error;
+ }
+ if (handle->channel_monitoring_pipes.kernel_consumer < 0) {
+ goto end;
+ }
+ ret = lttng_poll_add(poll_set,
+ handle->channel_monitoring_pipes.kernel_consumer,
+ LPOLLIN | LPOLLERR);
+ if (ret < 0) {
+ ERR("[notification-thread] Failed to add kernel channel monitoring pipe fd to pollset");
+ goto error;
+ }
+end:
+ return ret;
+error:
+ lttng_poll_clean(poll_set);
+ return ret;
+}
+
+static
+void fini_thread_state(struct notification_thread_state *state)
+{
+ int ret;
+
+ if (state->client_socket_ht) {
+ ret = handle_notification_thread_client_disconnect_all(state);
+ assert(!ret);
+ ret = cds_lfht_destroy(state->client_socket_ht, NULL);
+ assert(!ret);
+ }
+ if (state->triggers_ht) {
+ ret = handle_notification_thread_trigger_unregister_all(state);
+ assert(!ret);
+ ret = cds_lfht_destroy(state->triggers_ht, NULL);
+ assert(!ret);
+ }
+ if (state->channel_triggers_ht) {
+ ret = cds_lfht_destroy(state->channel_triggers_ht, NULL);
+ assert(!ret);
+ }
+ if (state->channel_state_ht) {
+ ret = cds_lfht_destroy(state->channel_state_ht, NULL);
+ assert(!ret);
+ }
+ if (state->notification_trigger_clients_ht) {
+ ret = cds_lfht_destroy(state->notification_trigger_clients_ht,
+ NULL);
+ assert(!ret);
+ }
+ if (state->channels_ht) {
+ ret = cds_lfht_destroy(state->channels_ht,
+ NULL);
+ assert(!ret);
+ }
+
+ if (state->notification_channel_socket >= 0) {
+ notification_channel_socket_destroy(
+ state->notification_channel_socket);
+ }
+ lttng_poll_clean(&state->events);
+}
+
+static
+int init_thread_state(struct notification_thread_handle *handle,
+ struct notification_thread_state *state)
+{
+ int ret;
+
+ memset(state, 0, sizeof(*state));
+ state->notification_channel_socket = -1;
+ lttng_poll_init(&state->events);
+
+ ret = notification_channel_socket_create();
+ if (ret < 0) {
+ goto end;
+ }
+ state->notification_channel_socket = ret;
+
+ ret = init_poll_set(&state->events, handle,
+ state->notification_channel_socket);
+ if (ret) {
+ goto end;
+ }
+
+ DBG("[notification-thread] Listening on notification channel socket");
+ ret = lttcomm_listen_unix_sock(state->notification_channel_socket);
+ if (ret < 0) {
+ ERR("[notification-thread] Listen failed on notification channel socket");
+ goto error;
+ }
+
+ state->client_socket_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+ CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->client_socket_ht) {
+ goto error;
+ }
+
+ state->channel_triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+ CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->channel_triggers_ht) {
+ goto error;
+ }
+
+ state->channel_state_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+ CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->channel_state_ht) {
+ goto error;
+ }
+
+ state->notification_trigger_clients_ht = cds_lfht_new(DEFAULT_HT_SIZE,
+ 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->notification_trigger_clients_ht) {
+ goto error;
+ }
+
+ state->channels_ht = cds_lfht_new(DEFAULT_HT_SIZE,
+ 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->channels_ht) {
+ goto error;
+ }
+
+ state->triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE,
+ 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!state->triggers_ht) {
+ goto error;
+ }
+end:
+ return 0;
+error:
+ fini_thread_state(state);
+ return -1;
+}
+
+static
+int handle_channel_monitoring_pipe(int fd, uint32_t revents,
+ struct notification_thread_handle *handle,
+ struct notification_thread_state *state)
+{
+ int ret = 0;
+ enum lttng_domain_type domain;
+
+ if (fd == handle->channel_monitoring_pipes.ust32_consumer ||
+ fd == handle->channel_monitoring_pipes.ust64_consumer) {
+ domain = LTTNG_DOMAIN_UST;
+ } else if (fd == handle->channel_monitoring_pipes.kernel_consumer) {
+ domain = LTTNG_DOMAIN_KERNEL;
+ } else {
+ abort();
+ }
+
+ if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ ret = lttng_poll_del(&state->events, fd);
+ if (ret) {
+ ERR("[notification-thread] Failed to remove consumer monitoring pipe from poll set");
+ }
+ goto end;
+ }
+
+ ret = handle_notification_thread_channel_sample(
+ state, fd, domain);
+ if (ret) {
+ ERR("[notification-thread] Consumer sample handling error occured");
+ ret = -1;
+ goto end;
+ }
+end:
+ return ret;
+}
+
+/*
+ * This thread services notification channel clients and commands received
+ * from various lttng-sessiond components over a command queue.
+ */
+void *thread_notification(void *data)
+{
+ int ret;
+ struct notification_thread_handle *handle = data;
+ struct notification_thread_state state;
+
+ DBG("[notification-thread] Started notification thread");
+
+ if (!handle) {
+ ERR("[notification-thread] Invalid thread context provided");
+ goto end;
+ }
+
+ rcu_register_thread();
+ rcu_thread_online();
+
+ health_register(health_sessiond, HEALTH_SESSIOND_TYPE_NOTIFICATION);
+ health_code_update();
+
+ ret = init_thread_state(handle, &state);
+ if (ret) {
+ goto end;
+ }
+
+ /* Ready to handle client connections. */
+ sessiond_notify_ready();
+
+ while (true) {
+ int fd_count, i;
+
+ health_poll_entry();
+ DBG("[notification-thread] Entering poll wait");
+ ret = lttng_poll_wait(&state.events, -1);
+ DBG("[notification-thread] Poll wait returned (%i)", ret);
+ health_poll_exit();
+ if (ret < 0) {
+ /*
+ * Restart interrupted system call.
+ */
+ if (errno == EINTR) {
+ continue;
+ }
+ ERR("[notification-thread] Error encountered during lttng_poll_wait (%i)", ret);
+ goto error;
+ }
+
+ fd_count = ret;
+ for (i = 0; i < fd_count; i++) {
+ int fd = LTTNG_POLL_GETFD(&state.events, i);
+ uint32_t revents = LTTNG_POLL_GETEV(&state.events, i);
+
+ DBG("[notification-thread] Handling fd (%i) activity (%u)", fd, revents);
+
+ if (fd == state.notification_channel_socket) {
+ if (revents & LPOLLIN) {
+ ret = handle_notification_thread_client_connect(
+ &state);
+ if (ret < 0) {
+ goto error;
+ }
+ } else if (revents &
+ (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ ERR("[notification-thread] Notification socket poll error");
+ goto error;
+ } else {
+ ERR("[notification-thread] Unexpected poll events %u for notification socket %i", revents, fd);
+ goto error;
+ }
+ } else if (fd == handle->cmd_queue.event_fd) {
+ ret = handle_notification_thread_command(handle,
+ &state);
+ if (ret < 0) {
+ DBG("[notification-thread] Error encountered while servicing command queue");
+ goto error;
+ } else if (ret > 0) {
+ goto exit;
+ }
+ } else if (fd == handle->channel_monitoring_pipes.ust32_consumer ||
+ fd == handle->channel_monitoring_pipes.ust64_consumer ||
+ fd == handle->channel_monitoring_pipes.kernel_consumer) {
+ ret = handle_channel_monitoring_pipe(fd,
+ revents, handle, &state);
+ if (ret) {
+ goto error;
+ }
+ } else {
+ /* Activity on a client's socket. */
+ if (revents & (LPOLLERR | LPOLLHUP | LPOLLRDHUP)) {
+ /*
+ * It doesn't matter if a command was
+ * pending on the client socket at this
+ * point since it now has no way to
+ * receive the notifications to which
+ * it was subscribing or unsubscribing.
+ */
+ ret = handle_notification_thread_client_disconnect(
+ fd, &state);
+ if (ret) {
+ goto error;
+ }
+ } else {
+ if (revents & LPOLLIN) {
+ ret = handle_notification_thread_client_in(
+ &state, fd);
+ if (ret) {
+ goto error;
+ }
+ }
+
+ if (revents & LPOLLOUT) {
+ ret = handle_notification_thread_client_out(
+ &state, fd);
+ if (ret) {
+ goto error;
+ }
+ }
+ }
+ }
+ }
+ }
+exit:
+error:
+ fini_thread_state(&state);
+ health_unregister(health_sessiond);
+ rcu_thread_offline();
+ rcu_unregister_thread();
+end:
+ return NULL;
+}
projects / lttng-tools.git / commitdiff
