X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Fmain.c;h=10ce291978227acf5d5e35eb5e623cbba80b82fb;hp=e7c5b6c52d28dfcd1fa80fdf925c8d5317f45b27;hb=f118099a14a45245993eedfe31cb36b3fd948d33;hpb=a8b66566890a353cc3a89836281541195ad69d73

diff --git a/src/bin/lttng-relayd/main.c b/src/bin/lttng-relayd/main.c
index e7c5b6c52..10ce29197 100644
--- a/src/bin/lttng-relayd/main.c
+++ b/src/bin/lttng-relayd/main.c
@@ -1,21 +1,11 @@
 /*
- * Copyright (C) 2012 - Julien Desfossez <jdesfossez@efficios.com>
- *                      David Goulet <dgoulet@efficios.com>
- *               2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2012 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@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.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -34,6 +24,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <sys/resource.h>
 #include <inttypes.h>
 #include <urcu/futex.h>
 #include <urcu/uatomic.h>
@@ -41,6 +32,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <strings.h>
+#include <ctype.h>
 
 #include <lttng/lttng.h>
 #include <common/common.h>
@@ -61,23 +53,26 @@
 #include <common/dynamic-buffer.h>
 #include <common/buffer-view.h>
 #include <common/string-utils/format.h>
+#include <common/fd-tracker/fd-tracker.h>
+#include <common/fd-tracker/utils.h>
 
-#include "version.h"
+#include "backward-compatibility-group-by.h"
 #include "cmd.h"
+#include "connection.h"
 #include "ctf-trace.h"
+#include "health-relayd.h"
 #include "index.h"
-#include "utils.h"
-#include "lttng-relayd.h"
 #include "live.h"
-#include "health-relayd.h"
-#include "testpoint.h"
-#include "viewer-stream.h"
+#include "lttng-relayd.h"
 #include "session.h"
+#include "sessiond-trace-chunks.h"
 #include "stream.h"
-#include "connection.h"
-#include "tracefile-array.h"
 #include "tcp_keep_alive.h"
-#include "sessiond-trace-chunks.h"
+#include "testpoint.h"
+#include "tracefile-array.h"
+#include "utils.h"
+#include "version.h"
+#include "viewer-stream.h"
 
 static const char *help_msg =
 #ifdef LTTNG_EMBED_HELP
@@ -97,7 +92,7 @@ enum relay_connection_status {
 
 /* command line options */
 char *opt_output_path, *opt_working_directory;
-static int opt_daemon, opt_background, opt_print_version;
+static int opt_daemon, opt_background, opt_print_version, opt_allow_clear = 1;
 enum relay_group_output_by opt_group_output_by = RELAYD_GROUP_OUTPUT_BY_UNKNOWN;
 
 /*
@@ -159,6 +154,9 @@ static uint64_t last_relay_stream_id;
  */
 static struct relay_conn_queue relay_conn_queue;
 
+/* Cap of file desriptors to be in simultaneous use by the relay daemon. */
+static unsigned int lttng_opt_fd_pool_size = -1;
+
 /* Global relay stream hash table. */
 struct lttng_ht *relay_streams_ht;
 
@@ -173,6 +171,9 @@ struct health_app *health_relayd;
 
 struct sessiond_trace_chunk_registry *sessiond_trace_chunk_registry;
 
+/* Global fd tracker. */
+struct fd_tracker *the_fd_tracker;
+
 static struct option long_options[] = {
 	{ "control-port", 1, 0, 'C', },
 	{ "data-port", 1, 0, 'D', },
@@ -180,6 +181,7 @@ static struct option long_options[] = {
 	{ "daemonize", 0, 0, 'd', },
 	{ "background", 0, 0, 'b', },
 	{ "group", 1, 0, 'g', },
+	{ "fd-pool-size", 1, 0, '\0', },
 	{ "help", 0, 0, 'h', },
 	{ "output", 1, 0, 'o', },
 	{ "verbose", 0, 0, 'v', },
@@ -188,6 +190,7 @@ static struct option long_options[] = {
 	{ "working-directory", 1, 0, 'w', },
 	{ "group-output-by-session", 0, 0, 's', },
 	{ "group-output-by-host", 0, 0, 'p', },
+	{ "disallow-clear", 0, 0, 'x' },
 	{ NULL, 0, 0, 0, },
 };
 
@@ -222,9 +225,27 @@ static int set_option(int opt, const char *arg, const char *optname)
 
 	switch (opt) {
 	case 0:
-		fprintf(stderr, "option %s", optname);
-		if (arg) {
-			fprintf(stderr, " with arg %s\n", arg);
+		if (!strcmp(optname, "fd-pool-size")) {
+			unsigned long v;
+
+			errno = 0;
+			v = strtoul(arg, NULL, 0);
+			if (errno != 0 || !isdigit((unsigned char) arg[0])) {
+				ERR("Wrong value in --fd-pool-size parameter: %s", arg);
+				ret = -1;
+				goto end;
+			}
+			if (v >= UINT_MAX) {
+				ERR("File descriptor cap overflow in --fd-pool-size parameter: %s", arg);
+				ret = -1;
+				goto end;
+			}
+			lttng_opt_fd_pool_size = (unsigned int) v;
+		} else {
+			fprintf(stderr, "unknown option %s", optname);
+			if (arg) {
+				fprintf(stderr, " with arg %s\n", arg);
+			}
 		}
 		break;
 	case 'C':
@@ -354,6 +375,10 @@ static int set_option(int opt, const char *arg, const char *optname)
 		}
 		opt_group_output_by = RELAYD_GROUP_OUTPUT_BY_HOST;
 		break;
+	case 'x':
+		/* Disallow clear */
+		opt_allow_clear = 0;
+		break;
 	default:
 		/* Unknown option or other error.
 		 * Error is printed by getopt, just return */
@@ -440,6 +465,56 @@ static int parse_env_options(void)
 	return ret;
 }
 
+static int set_fd_pool_size(void)
+{
+	int ret = 0;
+	struct rlimit rlimit;
+
+	ret = getrlimit(RLIMIT_NOFILE, &rlimit);
+	if (ret) {
+		PERROR("Failed to get file descriptor limit");
+		ret = -1;
+		goto end;
+	}
+
+	DBG("File descriptor count limits are %" PRIu64 " (soft) and %" PRIu64 " (hard)",
+			(uint64_t) rlimit.rlim_cur,
+			(uint64_t) rlimit.rlim_max);
+	if (lttng_opt_fd_pool_size == -1) {
+		/* Use default value (soft limit - reserve). */
+		if (rlimit.rlim_cur < DEFAULT_RELAYD_MIN_FD_POOL_SIZE) {
+			ERR("The process' file number limit is too low (%" PRIu64 "). The process' file number limit must be set to at least %i.",
+					(uint64_t) rlimit.rlim_cur, DEFAULT_RELAYD_MIN_FD_POOL_SIZE);
+			ret = -1;
+			goto end;
+		}
+		lttng_opt_fd_pool_size = rlimit.rlim_cur -
+				DEFAULT_RELAYD_FD_POOL_SIZE_RESERVE;
+		goto end;
+	}
+
+	if (lttng_opt_fd_pool_size < DEFAULT_RELAYD_MIN_FD_POOL_SIZE) {
+		ERR("File descriptor pool size must be set to at least %d",
+				DEFAULT_RELAYD_MIN_FD_POOL_SIZE);
+		ret = -1;
+		goto end;
+	}
+
+	if (lttng_opt_fd_pool_size > rlimit.rlim_cur) {
+		ERR("File descriptor pool size argument (%u) exceeds the process' soft limit (%" PRIu64 ").",
+				lttng_opt_fd_pool_size, (uint64_t) rlimit.rlim_cur);
+		ret = -1;
+		goto end;
+	}
+
+	DBG("File descriptor pool size argument (%u) adjusted to %u to accommodates transient fd uses",
+			lttng_opt_fd_pool_size,
+			lttng_opt_fd_pool_size - DEFAULT_RELAYD_FD_POOL_SIZE_RESERVE);
+	lttng_opt_fd_pool_size -= DEFAULT_RELAYD_FD_POOL_SIZE_RESERVE;
+end:
+	return ret;
+}
+
 static int set_options(int argc, char **argv)
 {
 	int c, ret = 0, option_index = 0, retval = 0;
@@ -557,10 +632,28 @@ static int set_options(int argc, char **argv)
 			goto exit;
 		}
 	}
+	ret = set_fd_pool_size();
+	if (ret) {
+		retval = -1;
+		goto exit;
+	}
 
 	if (opt_group_output_by == RELAYD_GROUP_OUTPUT_BY_UNKNOWN) {
 		opt_group_output_by = RELAYD_GROUP_OUTPUT_BY_HOST;
 	}
+	if (opt_allow_clear) {
+		/* Check if env variable exists. */
+		const char *value = lttng_secure_getenv(DEFAULT_LTTNG_RELAYD_DISALLOW_CLEAR_ENV);
+		if (value) {
+			ret = config_parse_value(value);
+			if (ret < 0) {
+				ERR("Invalid value for %s specified", DEFAULT_LTTNG_RELAYD_DISALLOW_CLEAR_ENV);
+				retval = -1;
+				goto exit;
+			}
+			opt_allow_clear = !ret;
+		}
+	}
 
 exit:
 	free(optstring);
@@ -569,13 +662,26 @@ exit:
 
 static void print_global_objects(void)
 {
-	rcu_register_thread();
-
 	print_viewer_streams();
 	print_relay_streams();
 	print_sessions();
+}
 
-	rcu_unregister_thread();
+static int noop_close(void *data, int *fds)
+{
+	return 0;
+}
+
+static void untrack_stdio(void)
+{
+	int fds[] = { fileno(stdout), fileno(stderr) };
+
+	/*
+	 * noop_close is used since we don't really want to close
+	 * the stdio output fds; we merely want to stop tracking them.
+	 */
+	(void) fd_tracker_close_unsuspendable_fd(the_fd_tracker,
+			fds, 2, noop_close, NULL);
 }
 
 /*
@@ -597,8 +703,30 @@ static void relayd_cleanup(void)
 	free(opt_output_path);
 	free(opt_working_directory);
 
+	if (health_relayd) {
+		health_app_destroy(health_relayd);
+	}
 	/* Close thread quit pipes */
-	utils_close_pipe(thread_quit_pipe);
+	if (health_quit_pipe[0] != -1) {
+		(void) fd_tracker_util_pipe_close(
+				the_fd_tracker, health_quit_pipe);
+	}
+	if (thread_quit_pipe[0] != -1) {
+		(void) fd_tracker_util_pipe_close(
+				the_fd_tracker, thread_quit_pipe);
+	}
+	if (sessiond_trace_chunk_registry) {
+		sessiond_trace_chunk_registry_destroy(
+				sessiond_trace_chunk_registry);
+	}
+	if (the_fd_tracker) {
+		untrack_stdio();
+		/*
+		 * fd_tracker_destroy() will log the contents of the fd-tracker
+		 * if a leak is detected.
+		 */
+		fd_tracker_destroy(the_fd_tracker);
+	}
 
 	uri_free(control_uri);
 	uri_free(data_uri);
@@ -760,17 +888,26 @@ void lttng_relay_notify_ready(void)
  */
 static int init_thread_quit_pipe(void)
 {
-	int ret;
-
-	ret = utils_create_pipe_cloexec(thread_quit_pipe);
+	return fd_tracker_util_pipe_open_cloexec(
+			the_fd_tracker, "Quit pipe", thread_quit_pipe);
+}
 
-	return ret;
+/*
+ * Init health quit pipe.
+ *
+ * Return -1 on error or 0 if all pipes are created.
+ */
+static int init_health_quit_pipe(void)
+{
+	return fd_tracker_util_pipe_open_cloexec(the_fd_tracker,
+			"Health quit pipe", health_quit_pipe);
 }
 
 /*
  * Create a poll set with O_CLOEXEC and add the thread quit pipe to the set.
  */
-static int create_thread_poll_set(struct lttng_poll_event *events, int size)
+static int create_named_thread_poll_set(struct lttng_poll_event *events,
+		int size, const char *name)
 {
 	int ret;
 
@@ -779,8 +916,10 @@ static int create_thread_poll_set(struct lttng_poll_event *events, int size)
 		goto error;
 	}
 
-	ret = lttng_poll_create(events, size, LTTNG_CLOEXEC);
-	if (ret < 0) {
+	ret = fd_tracker_util_poll_create(the_fd_tracker,
+			name, events, 1, LTTNG_CLOEXEC);
+	if (ret) {
+		PERROR("Failed to create \"%s\" poll file descriptor", name);
 		goto error;
 	}
 
@@ -810,13 +949,55 @@ static int check_thread_quit_pipe(int fd, uint32_t events)
 	return 0;
 }
 
+static int create_sock(void *data, int *out_fd)
+{
+	int ret;
+	struct lttcomm_sock *sock = data;
+
+	ret = lttcomm_create_sock(sock);
+	if (ret < 0) {
+		goto end;
+	}
+
+	*out_fd = sock->fd;
+end:
+	return ret;
+}
+
+static int close_sock(void *data, int *in_fd)
+{
+	struct lttcomm_sock *sock = data;
+
+	return sock->ops->close(sock);
+}
+
+static int accept_sock(void *data, int *out_fd)
+{
+	int ret = 0;
+	/* Socks is an array of in_sock, out_sock. */
+	struct lttcomm_sock **socks = data;
+	struct lttcomm_sock *in_sock = socks[0];
+
+	socks[1] = in_sock->ops->accept(in_sock);
+	if (!socks[1]) {
+		ret = -1;
+		goto end;
+	}
+	*out_fd = socks[1]->fd;
+end:
+	return ret;
+}
+
 /*
  * Create and init socket from uri.
  */
-static struct lttcomm_sock *relay_socket_create(struct lttng_uri *uri)
+static struct lttcomm_sock *relay_socket_create(struct lttng_uri *uri,
+		const char *name)
 {
-	int ret;
+	int ret, sock_fd;
 	struct lttcomm_sock *sock = NULL;
+	char uri_str[PATH_MAX];
+	char *formated_name = NULL;
 
 	sock = lttcomm_alloc_sock_from_uri(uri);
 	if (sock == NULL) {
@@ -824,11 +1005,29 @@ static struct lttcomm_sock *relay_socket_create(struct lttng_uri *uri)
 		goto error;
 	}
 
-	ret = lttcomm_create_sock(sock);
-	if (ret < 0) {
+	/*
+	 * Don't fail to create the socket if the name can't be built as it is
+	 * only used for debugging purposes.
+	 */
+	ret = uri_to_str_url(uri, uri_str, sizeof(uri_str));
+	uri_str[sizeof(uri_str) - 1] = '\0';
+	if (ret >= 0) {
+		ret = asprintf(&formated_name, "%s socket @ %s", name,
+				uri_str);
+		if (ret < 0) {
+			formated_name = NULL;
+		}
+	}
+
+	ret = fd_tracker_open_unsuspendable_fd(the_fd_tracker, &sock_fd,
+			(const char **) (formated_name ? &formated_name : NULL),
+			1, create_sock, sock);
+	if (ret) {
+		PERROR("Failed to open \"%s\" relay socket",
+				formated_name ?: "Unknown");
 		goto error;
 	}
-	DBG("Listening on sock %d", sock->fd);
+	DBG("Listening on %s socket %d", name, sock->fd);
 
 	ret = sock->ops->bind(sock);
 	if (ret < 0) {
@@ -842,15 +1041,38 @@ static struct lttcomm_sock *relay_socket_create(struct lttng_uri *uri)
 
 	}
 
+	free(formated_name);
 	return sock;
 
 error:
 	if (sock) {
 		lttcomm_destroy_sock(sock);
 	}
+	free(formated_name);
 	return NULL;
 }
 
+static
+struct lttcomm_sock *accept_relayd_sock(struct lttcomm_sock *listening_sock,
+		const char *name)
+{
+	int out_fd, ret;
+	struct lttcomm_sock *socks[2] = { listening_sock, NULL };
+	struct lttcomm_sock *new_sock = NULL;
+
+	ret = fd_tracker_open_unsuspendable_fd(
+			the_fd_tracker, &out_fd,
+			(const char **) &name,
+			1, accept_sock, &socks);
+	if (ret) {
+		goto end;
+	}
+	new_sock = socks[1];
+	DBG("%s accepted, socket %d", name, new_sock->fd);
+end:
+	return new_sock;
+}
+
 /*
  * This thread manages the listening for new connections on the network
  */
@@ -863,16 +1085,17 @@ static void *relay_thread_listener(void *data)
 
 	DBG("[thread] Relay listener started");
 
+	rcu_register_thread();
 	health_register(health_relayd, HEALTH_RELAYD_TYPE_LISTENER);
 
 	health_code_update();
 
-	control_sock = relay_socket_create(control_uri);
+	control_sock = relay_socket_create(control_uri, "Control listener");
 	if (!control_sock) {
 		goto error_sock_control;
 	}
 
-	data_sock = relay_socket_create(data_uri);
+	data_sock = relay_socket_create(data_uri, "Data listener");
 	if (!data_sock) {
 		goto error_sock_relay;
 	}
@@ -881,7 +1104,7 @@ static void *relay_thread_listener(void *data)
 	 * Pass 3 as size here for the thread quit pipe, control and
 	 * data socket.
 	 */
-	ret = create_thread_poll_set(&events, 3);
+	ret = create_named_thread_poll_set(&events, 3, "Listener thread epoll");
 	if (ret < 0) {
 		goto error_create_poll;
 	}
@@ -949,20 +1172,18 @@ restart:
 				 */
 				int val = 1;
 				struct relay_connection *new_conn;
-				struct lttcomm_sock *newsock;
+				struct lttcomm_sock *newsock = NULL;
 				enum connection_type type;
 
 				if (pollfd == data_sock->fd) {
 					type = RELAY_DATA;
-					newsock = data_sock->ops->accept(data_sock);
-					DBG("Relay data connection accepted, socket %d",
-							newsock->fd);
+					newsock = accept_relayd_sock(data_sock,
+							"Data socket to relayd");
 				} else {
 					assert(pollfd == control_sock->fd);
 					type = RELAY_CONTROL;
-					newsock = control_sock->ops->accept(control_sock);
-					DBG("Relay control connection accepted, socket %d",
-							newsock->fd);
+					newsock = accept_relayd_sock(control_sock,
+							"Control socket to relayd");
 				}
 				if (!newsock) {
 					PERROR("accepting sock");
@@ -1015,21 +1236,31 @@ exit:
 error:
 error_poll_add:
 error_testpoint:
-	lttng_poll_clean(&events);
+	(void) fd_tracker_util_poll_clean(the_fd_tracker, &events);
 error_create_poll:
 	if (data_sock->fd >= 0) {
-		ret = data_sock->ops->close(data_sock);
+		int data_sock_fd = data_sock->fd;
+
+		ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker,
+				&data_sock_fd, 1, close_sock,
+				data_sock);
 		if (ret) {
-			PERROR("close");
+			PERROR("Failed to close the data listener socket file descriptor");
 		}
+		data_sock->fd = -1;
 	}
 	lttcomm_destroy_sock(data_sock);
 error_sock_relay:
 	if (control_sock->fd >= 0) {
-		ret = control_sock->ops->close(control_sock);
+		int control_sock_fd = control_sock->fd;
+
+		ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker,
+				&control_sock_fd, 1, close_sock,
+				control_sock);
 		if (ret) {
-			PERROR("close");
+			PERROR("Failed to close the control listener socket file descriptor");
 		}
+		control_sock->fd = -1;
 	}
 	lttcomm_destroy_sock(control_sock);
 error_sock_control:
@@ -1038,6 +1269,7 @@ error_sock_control:
 		ERR("Health error occurred in %s", __func__);
 	}
 	health_unregister(health_relayd);
+	rcu_unregister_thread();
 	DBG("Relay listener thread cleanup complete");
 	lttng_relay_stop_threads();
 	return NULL;
@@ -1370,12 +1602,58 @@ static int relay_add_stream(const struct lttcomm_relayd_hdr *recv_hdr,
 		goto send_reply;
 	}
 
+	/*
+	 * Backward compatibility for --group-output-by-session.
+	 * Prior to lttng 2.11, the complete path is passed by the stream.
+	 * Starting at 2.11, lttng-relayd uses chunk. When dealing with producer
+	 * >=2.11 the chunk is responsible for the output path. When dealing
+	 * with producer < 2.11 the chunk output_path is the root output path
+	 * and the stream carries the complete path (path_name).
+	 * To support --group-output-by-session with older producer (<2.11), we
+	 * need to craft the path based on the stream path.
+	 */
+	if (opt_group_output_by == RELAYD_GROUP_OUTPUT_BY_SESSION) {
+		if (conn->minor < 4) {
+			/*
+			 * From 2.1 to 2.3, the session_name is not passed on
+			 * the RELAYD_CREATE_SESSION command. The session name
+			 * is necessary to detect the presence of a base_path
+			 * inside the stream path. Without it we cannot perform
+			 * a valid group-output-by-session transformation.
+			 */
+			WARN("Unable to perform a --group-by-session transformation for session %" PRIu64
+			     " for stream with path \"%s\" as it is produced by a peer using a protocol older than v2.4",
+					session->id, path_name);
+		} else if (conn->minor >= 4 && conn->minor < 11) {
+			char *group_by_session_path_name;
+
+			assert(session->session_name[0] != '\0');
+
+			group_by_session_path_name =
+					backward_compat_group_by_session(
+							path_name,
+							session->session_name,
+							session->creation_time.value);
+			if (!group_by_session_path_name) {
+				ERR("Failed to apply group by session to stream of session %" PRIu64,
+						session->id);
+				goto send_reply;
+			}
+
+			DBG("Transformed session path from \"%s\" to \"%s\" to honor per-session name grouping",
+					path_name, group_by_session_path_name);
+
+			free(path_name);
+			path_name = group_by_session_path_name;
+		}
+	}
+
 	trace = ctf_trace_get_by_path_or_create(session, path_name);
 	if (!trace) {
 		goto send_reply;
 	}
-	/* This stream here has one reference on the trace. */
 
+	/* This stream here has one reference on the trace. */
 	pthread_mutex_lock(&last_relay_stream_id_lock);
 	stream_handle = ++last_relay_stream_id;
 	pthread_mutex_unlock(&last_relay_stream_id_lock);
@@ -1475,7 +1753,7 @@ static int relay_close_stream(const struct lttcomm_relayd_hdr *recv_hdr,
 
 		vstream = viewer_stream_get_by_id(stream->stream_handle);
 		if (vstream) {
-			if (vstream->metadata_sent == stream->metadata_received) {
+			if (stream->no_new_metadata_notified) {
 				/*
 				 * Since all the metadata has been sent to the
 				 * viewer and that we have a request to close
@@ -2142,6 +2420,9 @@ static int relay_recv_index(const struct lttcomm_relayd_hdr *recv_hdr,
 		index_info.stream_instance_id =
 				be64toh(index_info.stream_instance_id);
 		index_info.packet_seq_num = be64toh(index_info.packet_seq_num);
+	} else {
+		index_info.stream_instance_id = -1ULL;
+		index_info.packet_seq_num = -1ULL;
 	}
 
 	stream = stream_get_by_id(index_info.relay_stream_id);
@@ -2286,7 +2567,7 @@ static int relay_rotate_session_streams(
 				session->sessiond_uuid, session->id,
 				rotate_streams.new_chunk_id.value);
 		if (!next_trace_chunk) {
-			char uuid_str[UUID_STR_LEN];
+			char uuid_str[LTTNG_UUID_STR_LEN];
 
 			lttng_uuid_to_str(session->sessiond_uuid, uuid_str);
 			ERR("Unknown next trace chunk in ROTATE_STREAMS command: sessiond_uuid = {%s}, session_id = %" PRIu64
@@ -2305,7 +2586,6 @@ static int relay_rotate_session_streams(
 		} else {
 			chunk_id_str = chunk_id_buf;
 		}
-		session->has_rotated = true;
 	}
 
 	DBG("Rotate %" PRIu32 " streams of session \"%s\" to chunk \"%s\"",
@@ -2391,7 +2671,7 @@ static int relay_create_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 	struct lttng_trace_chunk *chunk = NULL, *published_chunk = NULL;
 	enum lttng_error_code reply_code = LTTNG_OK;
 	enum lttng_trace_chunk_status chunk_status;
-	struct lttng_directory_handle session_output;
+	const char *new_path;
 
 	if (!session || !conn->version_check_done) {
 		ERR("Trying to create a trace chunk before version check");
@@ -2418,14 +2698,36 @@ static int relay_create_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 	msg->creation_timestamp = be64toh(msg->creation_timestamp);
 	msg->override_name_length = be32toh(msg->override_name_length);
 
+	if (session->current_trace_chunk &&
+			!lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
+		chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
+					DEFAULT_CHUNK_TMP_OLD_DIRECTORY);
+		if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+			ERR("Failed to rename old chunk");
+			ret = -1;
+			reply_code = LTTNG_ERR_UNK;
+			goto end;
+		}
+	}
+	session->ongoing_rotation = true;
+	if (!session->current_trace_chunk) {
+		if (!session->has_rotated) {
+			new_path = "";
+		} else {
+			new_path = NULL;
+		}
+	} else {
+		new_path = DEFAULT_CHUNK_TMP_NEW_DIRECTORY;
+	}
 	chunk = lttng_trace_chunk_create(
-			msg->chunk_id, msg->creation_timestamp);
+			msg->chunk_id, msg->creation_timestamp, new_path);
 	if (!chunk) {
 		ERR("Failed to create trace chunk in trace chunk creation command");
 		ret = -1;
 		reply_code = LTTNG_ERR_NOMEM;
 		goto end;
 	}
+	lttng_trace_chunk_set_fd_tracker(chunk, the_fd_tracker);
 
 	if (msg->override_name_length) {
 		const char *name;
@@ -2466,14 +2768,9 @@ static int relay_create_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 		goto end;
 	}
 
-	ret = session_init_output_directory_handle(
-			conn->session, &session_output);
-	if (ret) {
-		reply_code = LTTNG_ERR_CREATE_DIR_FAIL;
-		goto end;
-	}
-	chunk_status = lttng_trace_chunk_set_as_owner(chunk, &session_output);
-	lttng_directory_handle_fini(&session_output);
+	assert(conn->session->output_directory);
+	chunk_status = lttng_trace_chunk_set_as_owner(chunk,
+			conn->session->output_directory);
 	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 		reply_code = LTTNG_ERR_UNK;
 		ret = -1;
@@ -2486,7 +2783,7 @@ static int relay_create_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 			conn->session->id,
 			chunk);
 	if (!published_chunk) {
-		char uuid_str[UUID_STR_LEN];
+		char uuid_str[LTTNG_UUID_STR_LEN];
 
 		lttng_uuid_to_str(conn->session->sessiond_uuid, uuid_str);
 		ERR("Failed to publish chunk: sessiond_uuid = %s, session_id = %" PRIu64 ", chunk_id = %" PRIu64,
@@ -2513,6 +2810,9 @@ static int relay_create_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 			conn->session->current_trace_chunk;
 	conn->session->current_trace_chunk = published_chunk;
 	published_chunk = NULL;
+	if (!conn->session->pending_closure_trace_chunk) {
+		session->ongoing_rotation = false;
+	}
 end_unlock_session:
 	pthread_mutex_unlock(&conn->session->lock);
 end:
@@ -2555,6 +2855,7 @@ static int relay_close_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 	size_t path_length = 0;
 	const char *chunk_name = NULL;
 	struct lttng_dynamic_buffer reply_payload;
+	const char *new_path;
 
 	lttng_dynamic_buffer_init(&reply_payload);
 
@@ -2592,7 +2893,7 @@ static int relay_close_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 			conn->session->id,
 			chunk_id);
 	if (!chunk) {
-		char uuid_str[UUID_STR_LEN];
+		char uuid_str[LTTNG_UUID_STR_LEN];
 
 		lttng_uuid_to_str(conn->session->sessiond_uuid, uuid_str);
 		ERR("Failed to find chunk to close: sessiond_uuid = %s, session_id = %" PRIu64 ", chunk_id = %" PRIu64,
@@ -2605,6 +2906,20 @@ static int relay_close_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 	}
 
 	pthread_mutex_lock(&session->lock);
+	if (close_command.is_set &&
+			close_command.value == LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE) {
+		/*
+		 * Clear command. It is a protocol error to ask for a
+		 * clear on a relay which does not allow it. Querying
+		 * the configuration allows figuring out whether
+		 * clearing is allowed before doing the clear.
+		 */
+		if (!opt_allow_clear) {
+			ret = -1;
+			reply_code = LTTNG_ERR_INVALID_PROTOCOL;
+			goto end_unlock_session;
+		}
+	}
 	if (session->pending_closure_trace_chunk &&
 			session->pending_closure_trace_chunk != chunk) {
 		ERR("Trace chunk close command for session \"%s\" does not target the trace chunk pending closure",
@@ -2614,6 +2929,43 @@ static int relay_close_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 		goto end_unlock_session;
 	}
 
+	if (session->current_trace_chunk && session->current_trace_chunk != chunk &&
+			!lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
+		if (close_command.is_set &&
+				close_command.value == LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE &&
+				!session->has_rotated) {
+			/* New chunk stays in session output directory. */
+			new_path = "";
+		} else {
+			/* Use chunk name for new chunk. */
+			new_path = NULL;
+		}
+		/* Rename new chunk path. */
+		chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
+				new_path);
+		if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+			ret = -1;
+			goto end_unlock_session;
+		}
+		session->ongoing_rotation = false;
+	}
+	if ((!close_command.is_set ||
+			close_command.value == LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION) &&
+			!lttng_trace_chunk_get_name_overridden(chunk)) {
+		const char *old_path;
+
+		if (!session->has_rotated) {
+			old_path = "";
+		} else {
+			old_path = NULL;
+		}
+		/* We need to move back the .tmp_old_chunk to its rightful place. */
+		chunk_status = lttng_trace_chunk_rename_path(chunk, old_path);
+		if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+			ret = -1;
+			goto end_unlock_session;
+		}
+	}
 	chunk_status = lttng_trace_chunk_set_close_timestamp(
 			chunk, close_timestamp);
 	if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
@@ -2671,6 +3023,10 @@ static int relay_close_trace_chunk(const struct lttcomm_relayd_hdr *recv_hdr,
 			goto end_unlock_session;
 		}
 	}
+	if (close_command.is_set &&
+			close_command.value == LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED) {
+		session->has_rotated = true;
+	}
 	DBG("Reply chunk path on close: %s", closed_trace_chunk_path);
 	path_length = strlen(closed_trace_chunk_path) + 1;
 	if (path_length > UINT32_MAX) {
@@ -2797,6 +3153,57 @@ end_no_reply:
 	return ret;
 }
 
+/*
+ * relay_get_configuration: query whether feature is available
+ */
+static int relay_get_configuration(const struct lttcomm_relayd_hdr *recv_hdr,
+		struct relay_connection *conn,
+		const struct lttng_buffer_view *payload)
+{
+	int ret = 0;
+	ssize_t send_ret;
+	struct lttcomm_relayd_get_configuration *msg;
+	struct lttcomm_relayd_get_configuration_reply reply = {};
+	struct lttng_buffer_view header_view;
+	uint64_t query_flags = 0;
+	uint64_t result_flags = 0;
+
+	header_view = lttng_buffer_view_from_view(payload, 0, sizeof(*msg));
+	if (!header_view.data) {
+		ERR("Failed to receive payload of chunk close command");
+		ret = -1;
+		goto end_no_reply;
+	}
+
+	/* Convert to host endianness. */
+	msg = (typeof(msg)) header_view.data;
+	query_flags = be64toh(msg->query_flags);
+
+	if (query_flags) {
+		ret = LTTNG_ERR_INVALID_PROTOCOL;
+		goto reply;
+	}
+	if (opt_allow_clear) {
+		result_flags |= LTTCOMM_RELAYD_CONFIGURATION_FLAG_CLEAR_ALLOWED;
+	}
+	ret = 0;
+reply:
+	reply = (typeof(reply)){
+		.generic.ret_code = htobe32((uint32_t)
+			(ret == 0 ? LTTNG_OK : LTTNG_ERR_INVALID_PROTOCOL)),
+		.relayd_configuration_flags = htobe64(result_flags),
+	};
+	send_ret = conn->sock->ops->sendmsg(
+			conn->sock, &reply, sizeof(reply), 0);
+	if (send_ret < (ssize_t) sizeof(reply)) {
+		ERR("Failed to send \"get configuration\" command reply (ret = %zd)",
+				send_ret);
+		ret = -1;
+	}
+end_no_reply:
+	return ret;
+}
+
 #define DBG_CMD(cmd_name, conn) \
 		DBG3("Processing \"%s\" command for socket %i", cmd_name, conn->sock->fd);
 
@@ -2875,6 +3282,10 @@ static int relay_process_control_command(struct relay_connection *conn,
 		DBG_CMD("RELAYD_TRACE_CHUNK_EXISTS", conn);
 		ret = relay_trace_chunk_exists(header, conn, payload);
 		break;
+	case RELAYD_GET_CONFIGURATION:
+		DBG_CMD("RELAYD_GET_CONFIGURATION", conn);
+		ret = relay_get_configuration(header, conn, payload);
+		break;
 	case RELAYD_UPDATE_SYNC_INFO:
 	default:
 		ERR("Received unknown command (%u)", header->cmd);
@@ -3351,7 +3762,8 @@ static void cleanup_connection_pollfd(struct lttng_poll_event *events, int pollf
 
 	(void) lttng_poll_del(events, pollfd);
 
-	ret = close(pollfd);
+	ret = fd_tracker_close_unsuspendable_fd(the_fd_tracker, &pollfd, 1,
+			fd_tracker_util_close_fd, NULL);
 	if (ret < 0) {
 		ERR("Closing pollfd %d", pollfd);
 	}
@@ -3413,7 +3825,7 @@ static void *relay_thread_worker(void *data)
 		goto relay_connections_ht_error;
 	}
 
-	ret = create_thread_poll_set(&events, 2);
+	ret = create_named_thread_poll_set(&events, 2, "Worker thread epoll");
 	if (ret < 0) {
 		goto error_poll_create;
 	}
@@ -3682,12 +4094,13 @@ error:
 	}
 	rcu_read_unlock();
 
-	lttng_poll_clean(&events);
+	(void) fd_tracker_util_poll_clean(the_fd_tracker, &events);
 error_poll_create:
 	lttng_ht_destroy(relay_connections_ht);
 relay_connections_ht_error:
 	/* Close relay conn pipes */
-	utils_close_pipe(relay_conn_pipe);
+	(void) fd_tracker_util_pipe_close(the_fd_tracker,
+			relay_conn_pipe);
 	if (err) {
 		DBG("Thread exited with error");
 	}
@@ -3709,11 +4122,24 @@ error_testpoint:
  */
 static int create_relay_conn_pipe(void)
 {
-	int ret;
+	return fd_tracker_util_pipe_open_cloexec(the_fd_tracker,
+			"Relayd connection pipe", relay_conn_pipe);
+}
 
-	ret = utils_create_pipe_cloexec(relay_conn_pipe);
+static int stdio_open(void *data, int *fds)
+{
+	fds[0] = fileno(stdout);
+	fds[1] = fileno(stderr);
+	return 0;
+}
 
-	return ret;
+static int track_stdio(void)
+{
+	int fds[2];
+	const char *names[] = { "stdout", "stderr" };
+
+	return fd_tracker_open_unsuspendable_fd(the_fd_tracker, fds,
+			names, 2, stdio_open, NULL);
 }
 
 /*
@@ -3721,8 +4147,10 @@ static int create_relay_conn_pipe(void)
  */
 int main(int argc, char **argv)
 {
+	bool thread_is_rcu_registered = false;
 	int ret = 0, retval = 0;
 	void *status;
+	char *unlinked_file_directory_path = NULL, *output_path = NULL;
 
 	/* Parse environment variables */
 	ret = parse_env_options();
@@ -3754,6 +4182,14 @@ int main(int argc, char **argv)
 		goto exit_options;
 	}
 
+	ret = fclose(stdin);
+	if (ret) {
+		PERROR("Failed to close stdin");
+		goto exit_options;
+	}
+
+	DBG("Clear command %s", opt_allow_clear ? "allowed" : "disallowed");
+
 	/* Try to create directory if -o, --output is specified. */
 	if (opt_output_path) {
 		if (*opt_output_path != '/') {
@@ -3773,23 +4209,12 @@ int main(int argc, char **argv)
 
 	/* Daemonize */
 	if (opt_daemon || opt_background) {
-		int i;
-
 		ret = lttng_daemonize(&child_ppid, &recv_child_signal,
 			!opt_background);
 		if (ret < 0) {
 			retval = -1;
 			goto exit_options;
 		}
-
-		/*
-		 * We are in the child. Make sure all other file
-		 * descriptors are closed, in case we are called with
-		 * more opened file descriptors than the standard ones.
-		 */
-		for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) {
-			(void) close(i);
-		}
 	}
 
 	if (opt_working_directory) {
@@ -3804,7 +4229,44 @@ int main(int argc, char **argv)
 	if (!sessiond_trace_chunk_registry) {
 		ERR("Failed to initialize session daemon trace chunk registry");
 		retval = -1;
-		goto exit_sessiond_trace_chunk_registry;
+		goto exit_options;
+	}
+
+	/*
+	 * The RCU thread registration (and use, through the fd-tracker's
+	 * creation) is done after the daemonization to allow us to not
+	 * deal with liburcu's fork() management as the call RCU needs to
+	 * be restored.
+	 */
+	rcu_register_thread();
+	thread_is_rcu_registered = true;
+
+	output_path = create_output_path("");
+	if (!output_path) {
+		ERR("Failed to get output path");
+		retval = -1;
+		goto exit_options;
+	}
+	ret = asprintf(&unlinked_file_directory_path, "%s/%s", output_path,
+			DEFAULT_UNLINKED_FILES_DIRECTORY);
+	free(output_path);
+	if (ret < 0) {
+		ERR("Failed to format unlinked file directory path");
+		retval = -1;
+		goto exit_options;
+	}
+	the_fd_tracker = fd_tracker_create(
+			unlinked_file_directory_path, lttng_opt_fd_pool_size);
+	free(unlinked_file_directory_path);
+	if (!the_fd_tracker) {
+		retval = -1;
+		goto exit_options;
+	}
+
+	ret = track_stdio();
+	if (ret) {
+		retval = -1;
+		goto exit_options;
 	}
 
 	/* Initialize thread health monitoring */
@@ -3812,19 +4274,19 @@ int main(int argc, char **argv)
 	if (!health_relayd) {
 		PERROR("health_app_create error");
 		retval = -1;
-		goto exit_health_app_create;
+		goto exit_options;
 	}
 
 	/* Create thread quit pipe */
 	if (init_thread_quit_pipe()) {
 		retval = -1;
-		goto exit_init_data;
+		goto exit_options;
 	}
 
 	/* Setup the thread apps communication pipe. */
 	if (create_relay_conn_pipe()) {
 		retval = -1;
-		goto exit_init_data;
+		goto exit_options;
 	}
 
 	/* Init relay command queue. */
@@ -3838,27 +4300,27 @@ int main(int argc, char **argv)
 	sessions_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 	if (!sessions_ht) {
 		retval = -1;
-		goto exit_init_data;
+		goto exit_options;
 	}
 
 	/* tables of streams indexed by stream ID */
 	relay_streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 	if (!relay_streams_ht) {
 		retval = -1;
-		goto exit_init_data;
+		goto exit_options;
 	}
 
 	/* tables of streams indexed by stream ID */
 	viewer_streams_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 	if (!viewer_streams_ht) {
 		retval = -1;
-		goto exit_init_data;
+		goto exit_options;
 	}
 
-	ret = utils_create_pipe(health_quit_pipe);
+	ret = init_health_quit_pipe();
 	if (ret) {
 		retval = -1;
-		goto exit_health_quit_pipe;
+		goto exit_options;
 	}
 
 	/* Create thread to manage the client socket */
@@ -3868,7 +4330,7 @@ int main(int argc, char **argv)
 		errno = ret;
 		PERROR("pthread_create health");
 		retval = -1;
-		goto exit_health_thread;
+		goto exit_options;
 	}
 
 	/* Setup the dispatcher thread */
@@ -3949,16 +4411,6 @@ exit_dispatcher_thread:
 		PERROR("pthread_join health_thread");
 		retval = -1;
 	}
-exit_health_thread:
-
-	utils_close_pipe(health_quit_pipe);
-exit_health_quit_pipe:
-
-exit_init_data:
-	health_app_destroy(health_relayd);
-	sessiond_trace_chunk_registry_destroy(sessiond_trace_chunk_registry);
-exit_health_app_create:
-exit_sessiond_trace_chunk_registry:
 exit_options:
 	/*
 	 * Wait for all pending call_rcu work to complete before tearing
@@ -3971,6 +4423,10 @@ exit_options:
 	/* Ensure all prior call_rcu are done. */
 	rcu_barrier();
 
+	if (thread_is_rcu_registered) {
+		rcu_unregister_thread();
+	}
+
 	if (!retval) {
 		exit(EXIT_SUCCESS);
 	} else {