X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;ds=sidebyside;f=src%2Fbin%2Flttng-sessiond%2Fmain.c;h=abae17fd65570400ac7f6a2aa955cd80ce0064d6;hb=99d688f2849a22589351cf353edce0c756cddb74;hp=7a0cdb81c83ac0c451341aa41ed29c57d4d3cb77;hpb=a7333da73c2083281c5ec833d041b7acf0d10d0b;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 7a0cdb81c..abae17fd6 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -177,7 +177,6 @@ static int dispatch_thread_exit;
 /* Sockets and FDs */
 static int client_sock = -1;
 static int apps_sock = -1;
-static int kernel_poll_pipe[2] = { -1, -1 };
 
 /*
  * This pipe is used to inform the thread managing application communication
@@ -211,18 +210,6 @@ static pthread_t timer_thread;
  */
 static struct ust_cmd_queue ust_cmd_queue;
 
-/*
- * Pointer initialized before thread creation.
- *
- * This points to the tracing session list containing the session count and a
- * mutex lock. The lock MUST be taken if you iterate over the list. The lock
- * MUST NOT be taken if you call a public function in session.c.
- *
- * The lock is nested inside the structure: session_list_ptr->lock. Please use
- * session_lock_list and session_unlock_list for lock acquisition.
- */
-static struct ltt_session_list *session_list_ptr;
-
 static const char *module_proc_lttng = "/proc/lttng";
 
 /*
@@ -388,7 +375,7 @@ static void wait_consumer(struct consumer_data *consumer_data)
 static void sessiond_cleanup(void)
 {
 	int ret;
-	struct ltt_session *sess, *stmp;
+	struct ltt_session_list *session_list = session_get_list();
 
 	DBG("Cleanup sessiond");
 
@@ -434,19 +421,7 @@ static void sessiond_cleanup(void)
 	DBG("Removing directory %s", config.consumerd64_path.value);
 	(void) rmdir(config.consumerd64_path.value);
 
-	DBG("Cleaning up all sessions");
-
-	/* Destroy session list mutex */
-	if (session_list_ptr != NULL) {
-		pthread_mutex_destroy(&session_list_ptr->lock);
-
-		/* Cleanup ALL session */
-		cds_list_for_each_entry_safe(sess, stmp,
-				&session_list_ptr->head, list) {
-			cmd_destroy_session(sess, kernel_poll_pipe[1],
-					notification_thread_handle);
-		}
-	}
+	pthread_mutex_destroy(&session_list->lock);
 
 	wait_consumer(&kconsumer_data);
 	wait_consumer(&ustconsumer64_data);
@@ -619,16 +594,21 @@ static int setup_lttng_msg_no_cmd_header(struct command_ctx *cmd_ctx,
 static int update_kernel_poll(struct lttng_poll_event *events)
 {
 	int ret;
-	struct ltt_session *session;
 	struct ltt_kernel_channel *channel;
+	struct ltt_session *session;
+	const struct ltt_session_list *session_list = session_get_list();
 
 	DBG("Updating kernel poll set");
 
 	session_lock_list();
-	cds_list_for_each_entry(session, &session_list_ptr->head, list) {
+	cds_list_for_each_entry(session, &session_list->head, list) {
+		if (!session_get(session)) {
+			continue;
+		}
 		session_lock(session);
 		if (session->kernel_session == NULL) {
 			session_unlock(session);
+			session_put(session);
 			continue;
 		}
 
@@ -638,6 +618,7 @@ static int update_kernel_poll(struct lttng_poll_event *events)
 			ret = lttng_poll_add(events, channel->fd, LPOLLIN | LPOLLRDNORM);
 			if (ret < 0) {
 				session_unlock(session);
+				session_put(session);
 				goto error;
 			}
 			DBG("Channel fd %d added to kernel set", channel->fd);
@@ -665,14 +646,19 @@ static int update_kernel_stream(int fd)
 	struct ltt_session *session;
 	struct ltt_kernel_session *ksess;
 	struct ltt_kernel_channel *channel;
+	const struct ltt_session_list *session_list = session_get_list();
 
 	DBG("Updating kernel streams for channel fd %d", fd);
 
 	session_lock_list();
-	cds_list_for_each_entry(session, &session_list_ptr->head, list) {
+	cds_list_for_each_entry(session, &session_list->head, list) {
+		if (!session_get(session)) {
+			continue;
+		}
 		session_lock(session);
 		if (session->kernel_session == NULL) {
 			session_unlock(session);
+			session_put(session);
 			continue;
 		}
 		ksess = session->kernel_session;
@@ -720,12 +706,14 @@ static int update_kernel_stream(int fd)
 			rcu_read_unlock();
 		}
 		session_unlock(session);
+		session_put(session);
 	}
 	session_unlock_list();
 	return ret;
 
 error:
 	session_unlock(session);
+	session_put(session);
 	session_unlock_list();
 	return ret;
 }
@@ -737,6 +725,7 @@ error:
 static void update_ust_app(int app_sock)
 {
 	struct ltt_session *sess, *stmp;
+	const struct ltt_session_list *session_list = session_get_list();
 
 	/* Consumer is in an ERROR state. Stop any application update. */
 	if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) {
@@ -745,9 +734,12 @@ static void update_ust_app(int app_sock)
 	}
 
 	/* For all tracing session(s) */
-	cds_list_for_each_entry_safe(sess, stmp, &session_list_ptr->head, list) {
+	cds_list_for_each_entry_safe(sess, stmp, &session_list->head, list) {
 		struct ust_app *app;
 
+		if (!session_get(sess)) {
+			continue;
+		}
 		session_lock(sess);
 		if (!sess->ust_session) {
 			goto unlock_session;
@@ -771,6 +763,7 @@ static void update_ust_app(int app_sock)
 		rcu_read_unlock();
 	unlock_session:
 		session_unlock(sess);
+		session_put(sess);
 	}
 }
 
@@ -2716,17 +2709,22 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
 {
 	unsigned int i = 0;
 	struct ltt_session *session;
+	const struct ltt_session_list *session_list = session_get_list();
 
 	DBG("Counting number of available session for UID %d GID %d",
 			uid, gid);
-	cds_list_for_each_entry(session, &session_list_ptr->head, list) {
-		/*
-		 * Only list the sessions the user can control.
-		 */
-		if (!session_access_ok(session, uid, gid)) {
+	cds_list_for_each_entry(session, &session_list->head, list) {
+		if (!session_get(session)) {
 			continue;
 		}
-		i++;
+		session_lock(session);
+		/* Only count the sessions the user can control. */
+		if (session_access_ok(session, uid, gid) &&
+				!session->destroyed) {
+			i++;
+		}
+		session_unlock(session);
+		session_put(session);
 	}
 	return i;
 }
@@ -3213,7 +3211,8 @@ skip_domain:
 	if (need_tracing_session) {
 		if (!session_access_ok(cmd_ctx->session,
 				LTTNG_SOCK_GET_UID_CRED(&cmd_ctx->creds),
-				LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds))) {
+				LTTNG_SOCK_GET_GID_CRED(&cmd_ctx->creds)) ||
+				cmd_ctx->session->destroyed) {
 			ret = LTTNG_ERR_EPERM;
 			goto error;
 		}
@@ -3728,11 +3727,8 @@ error_add_context:
 	}
 	case LTTNG_DESTROY_SESSION:
 	{
-		ret = cmd_destroy_session(cmd_ctx->session, kernel_poll_pipe[1],
+		ret = cmd_destroy_session(cmd_ctx->session,
 				notification_thread_handle);
-
-		/* Set session to NULL so we do not unlock it after free. */
-		cmd_ctx->session = NULL;
 		break;
 	}
 	case LTTNG_LIST_DOMAINS:
@@ -4189,6 +4185,7 @@ error:
 setup_error:
 	if (cmd_ctx->session) {
 		session_unlock(cmd_ctx->session);
+		session_put(cmd_ctx->session);
 	}
 	if (need_tracing_session) {
 		session_unlock_list();
@@ -4474,6 +4471,9 @@ static void *thread_manage_clients(void *data)
 
 	health_code_update();
 
+	/* Set state as running. */
+	sessiond_set_client_thread_state(true);
+
 	while (1) {
 		const struct cmd_completion_handler *cmd_completion_handler;
 
@@ -4708,6 +4708,9 @@ error_create_poll:
 		errno = ret;
 		PERROR("join_consumer ust64");
 	}
+
+	/* Set state as non-running. */
+	sessiond_set_client_thread_state(false);
 	return NULL;
 }
 
@@ -5630,6 +5633,50 @@ end:
 	return ret;
 }
 
+static void destroy_all_sessions_and_wait(void)
+{
+	struct ltt_session *session, *tmp;
+	struct ltt_session_list *session_list;
+
+	session_list = session_get_list();
+	DBG("Initiating destruction of all sessions");
+
+	if (!session_list) {
+		return;
+	}
+
+	/*
+	 * Ensure that the client thread is no longer accepting new commands,
+	 * which could cause new sessions to be created.
+	 */
+	sessiond_wait_client_thread_stopped();
+
+	session_lock_list();
+	/* Initiate the destruction of all sessions. */
+	cds_list_for_each_entry_safe(session, tmp,
+			&session_list->head, list) {
+		if (!session_get(session)) {
+			continue;
+		}
+
+		session_lock(session);
+		if (session->destroyed) {
+			goto unlock_session;
+		}
+		(void) cmd_destroy_session(session,
+				notification_thread_handle);
+	unlock_session:
+		session_unlock(session);
+		session_put(session);
+	}
+	session_unlock_list();
+
+	/* Wait for the destruction of all sessions to complete. */
+	DBG("Waiting for the destruction of all sessions to complete");
+	session_list_wait_empty();
+	DBG("Destruction of all sessions completed");
+}
+
 /*
  * main
  */
@@ -5961,12 +6008,6 @@ int main(int argc, char **argv)
 	/* Init UST command queue. */
 	cds_wfcq_init(&ust_cmd_queue.head, &ust_cmd_queue.tail);
 
-	/*
-	 * Get session list pointer. This pointer MUST NOT be free'd. This list
-	 * is statically declared in session.c
-	 */
-	session_list_ptr = session_get_list();
-
 	cmd_init();
 
 	/* Check for the application socket timeout env variable. */
@@ -6175,6 +6216,10 @@ int main(int argc, char **argv)
 		PERROR("pthread_join load_session_thread");
 		retval = -1;
 	}
+
+	/* Initiate teardown once activity occurs on the quit pipe. */
+	sessiond_wait_for_quit_pipe(-1U);
+	destroy_all_sessions_and_wait();
 exit_load_session:
 
 	if (is_root && !config.no_kernel) {