Launch the notification thread using lttng_thread
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread.c
index b580faa2682e1fa7a3a632fc095d93af3ef41b5d..9809e6190cd60cbb453cea62b704a62e6da84cc5 100644 (file)
@@ -37,6 +37,7 @@
 #include "notification-thread-commands.h"
 #include "lttng-sessiond.h"
 #include "health-sessiond.h"
+#include "thread.h"
 
 #include <urcu.h>
 #include <urcu/list.h>
@@ -54,17 +55,13 @@ void notification_thread_handle_destroy(
                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");
-       }
-
        assert(cds_list_empty(&handle->cmd_queue.list));
        pthread_mutex_destroy(&handle->cmd_queue.lock);
+       sem_destroy(&handle->ready);
 
+       if (handle->cmd_queue.event_pipe) {
+               lttng_pipe_destroy(handle->cmd_queue.event_pipe);
+       }
        if (handle->channel_monitoring_pipes.ust32_consumer >= 0) {
                ret = close(handle->channel_monitoring_pipes.ust32_consumer);
                if (ret) {
@@ -94,18 +91,24 @@ struct notification_thread_handle *notification_thread_handle_create(
 {
        int ret;
        struct notification_thread_handle *handle;
+       struct lttng_pipe *event_pipe = NULL;
 
        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 | EFD_SEMAPHORE);
-       if (handle->cmd_queue.event_fd < 0) {
-               PERROR("eventfd notification command queue");
+       sem_init(&handle->ready, 0, 0);
+
+       event_pipe = lttng_pipe_open(FD_CLOEXEC);
+       if (!event_pipe) {
+               ERR("event_pipe creation");
                goto error;
        }
+
+       handle->cmd_queue.event_pipe = event_pipe;
+       event_pipe = NULL;
+
        CDS_INIT_LIST_HEAD(&handle->cmd_queue.list);
        ret = pthread_mutex_init(&handle->cmd_queue.lock, NULL);
        if (ret) {
@@ -145,6 +148,7 @@ struct notification_thread_handle *notification_thread_handle_create(
 end:
        return handle;
 error:
+       lttng_pipe_destroy(event_pipe);
        notification_thread_handle_destroy(handle);
        return NULL;
 }
@@ -236,7 +240,7 @@ int notification_channel_socket_create(void)
 
        if (getuid() == 0) {
                ret = chown(sock_path, 0,
-                               utils_get_group_id(tracing_group_name));
+                               utils_get_group_id(config.tracing_group_name.value));
                if (ret) {
                        ERR("Failed to set the notification channel socket's group");
                        ret = -1;
@@ -282,7 +286,7 @@ int init_poll_set(struct lttng_poll_event *poll_set,
                ERR("[notification-thread] Failed to add notification channel socket to pollset");
                goto error;
        }
-       ret = lttng_poll_add(poll_set, handle->cmd_queue.event_fd,
+       ret = lttng_poll_add(poll_set, lttng_pipe_get_readfd(handle->cmd_queue.event_pipe),
                        LPOLLIN | LPOLLERR);
        if (ret < 0) {
                ERR("[notification-thread] Failed to add notification command queue event fd to pollset");
@@ -350,11 +354,21 @@ void fini_thread_state(struct notification_thread_state *state)
                assert(!ret);
        }
        if (state->channels_ht) {
-               ret = cds_lfht_destroy(state->channels_ht,
-                               NULL);
+               ret = cds_lfht_destroy(state->channels_ht, NULL);
+               assert(!ret);
+       }
+       if (state->sessions_ht) {
+               ret = cds_lfht_destroy(state->sessions_ht, NULL);
+               assert(!ret);
+       }
+       /*
+        * Must be destroyed after all channels have been destroyed.
+        * See comment in struct lttng_session_trigger_list.
+        */
+       if (state->session_triggers_ht) {
+               ret = cds_lfht_destroy(state->session_triggers_ht, NULL);
                assert(!ret);
        }
-
        if (state->notification_channel_socket >= 0) {
                notification_channel_socket_destroy(
                                state->notification_channel_socket);
@@ -362,6 +376,21 @@ void fini_thread_state(struct notification_thread_state *state)
        lttng_poll_clean(&state->events);
 }
 
+static
+void mark_thread_as_ready(struct notification_thread_handle *handle)
+{
+       DBG("Marking notification thread as ready");
+       sem_post(&handle->ready);
+}
+
+static
+void wait_until_thread_is_ready(struct notification_thread_handle *handle)
+{
+       DBG("Waiting for notification thread to be ready");
+       sem_wait(&handle->ready);
+       DBG("Notification thread is ready");
+}
+
 static
 int init_thread_state(struct notification_thread_handle *handle,
                struct notification_thread_state *state)
@@ -403,6 +432,12 @@ int init_thread_state(struct notification_thread_handle *handle,
                goto error;
        }
 
+       state->session_triggers_ht = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+                       CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+       if (!state->session_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) {
@@ -420,12 +455,17 @@ int init_thread_state(struct notification_thread_handle *handle,
        if (!state->channels_ht) {
                goto error;
        }
-
+       state->sessions_ht = cds_lfht_new(DEFAULT_HT_SIZE,
+                       1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+       if (!state->sessions_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;
        }
+       mark_thread_as_ready(handle);
 end:
        return 0;
 error:
@@ -473,6 +513,7 @@ end:
  * This thread services notification channel clients and commands received
  * from various lttng-sessiond components over a command queue.
  */
+static
 void *thread_notification(void *data)
 {
        int ret;
@@ -497,9 +538,6 @@ void *thread_notification(void *data)
                goto end;
        }
 
-       /* Ready to handle client connections. */
-       sessiond_notify_ready();
-
        while (true) {
                int fd_count, i;
 
@@ -544,7 +582,7 @@ void *thread_notification(void *data)
                                        ERR("[notification-thread] Unexpected poll events %u for notification socket %i", revents, fd);
                                        goto error;
                                }
-                       } else if (fd == handle->cmd_queue.event_fd) {
+                       } else if (fd == lttng_pipe_get_readfd(handle->cmd_queue.event_pipe)) {
                                ret = handle_notification_thread_command(handle,
                                                &state);
                                if (ret < 0) {
@@ -605,3 +643,37 @@ error:
 end:
        return NULL;
 }
+
+static
+bool shutdown_notification_thread(void *thread_data)
+{
+       struct notification_thread_handle *handle = thread_data;
+
+       notification_thread_command_quit(handle);
+       return true;
+}
+
+bool launch_notification_thread(struct notification_thread_handle *handle)
+{
+       struct lttng_thread *thread;
+
+       thread = lttng_thread_create("Notification",
+                       thread_notification,
+                       shutdown_notification_thread,
+                       NULL,
+                       handle);
+       if (!thread) {
+               goto error;
+       }
+
+       /*
+        * Wait for the thread to be marked as "ready" before returning
+        * as other subsystems depend on the notification subsystem
+        * (e.g. rotation thread).
+        */
+       wait_until_thread_is_ready(handle);
+       lttng_thread_put(thread);
+       return true;
+error:
+       return false;
+}
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