--- /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;
+ }
+
+ 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 6:
+ * - quit pipe,
+ * - notification channel socket (listen for new connections),
+ * - command queue event fd (internal sessiond commands),
+ * - consumerd (32-bit user space) channel monitor pipe,
+ * - consumerd (64-but user space) channel monitor pipe,
+ * - consumerd (kernel) channel monitor pipe.
+ */
+ ret = sessiond_set_thread_pollset(poll_set, 6);
+ 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;
+}
+
+/*
+ * This thread services notification channel clients and received notifications
+ * 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);
+
+ /* Thread quit pipe has been closed. Killing thread. */
+ if (sessiond_check_thread_quit_pipe(fd, revents)) {
+ DBG("[notification-thread] Quit pipe signaled, exiting.");
+ goto exit;
+ }
+
+ 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) {
+ goto error;
+ }
+ } else if (fd == handle->channel_monitoring_pipes.ust32_consumer) {
+ ret = handle_notification_thread_channel_sample(
+ &state, fd, LTTNG_DOMAIN_UST);
+ if (ret) {
+ goto error;
+ }
+ } else if (fd == handle->channel_monitoring_pipes.ust64_consumer) {
+ ret = handle_notification_thread_channel_sample(
+ &state, fd, LTTNG_DOMAIN_UST);
+ if (ret) {
+ goto error;
+ }
+ } else if (fd == handle->channel_monitoring_pipes.kernel_consumer) {
+ ret = handle_notification_thread_channel_sample(
+ &state, fd, LTTNG_DOMAIN_KERNEL);
+ 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 now 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(
+ &state, fd);
+ if (ret) {
+ goto error;
+ }
+ } else {
+ DBG("[notification-thread] Unexpected poll events %u for notification socket %i", revents, fd);
+ }
+ }
+ }
+ }
+exit:
+error:
+ fini_thread_state(&state);
+ health_unregister(health_sessiond);
+ rcu_thread_offline();
+ rcu_unregister_thread();
+end:
+ return NULL;
+}
projects / deliverable / lttng-tools.git / blobdiff