Clean-up: sessiond command: change space to tabs
[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c
index 6e5128917b474cd4d970669ba6ec25d06ef4dba8..15e559d03b5c31faa0e08b39e6f1921dcd1c54c2 100644 (file)
@@ -1,21 +1,14 @@
 /*
- * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
- * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2016 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.
+ * 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.
  */
 
+#include "bin/lttng-sessiond/tracker.h"
+#include "lttng/lttng-error.h"
+#include "lttng/tracker.h"
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <inttypes.h>
@@ -33,6 +26,8 @@
 #include <common/kernel-ctl/kernel-ctl.h>
 #include <common/dynamic-buffer.h>
 #include <common/buffer-view.h>
+#include <common/payload.h>
+#include <common/payload-view.h>
 #include <common/trace-chunk.h>
 #include <lttng/location-internal.h>
 #include <lttng/trigger/trigger-internal.h>
 struct cmd_destroy_session_reply_context {
        int reply_sock_fd;
        bool implicit_rotation_on_destroy;
+       /*
+        * Indicates whether or not an error occurred while launching the
+        * destruction of a session.
+        */
+       enum lttng_error_code destruction_status;
 };
 
 static enum lttng_error_code wait_on_path(void *path);
@@ -107,7 +107,7 @@ static uint64_t relayd_net_seq_idx;
 
 static int validate_ust_event_name(const char *);
 static int cmd_enable_event_internal(struct ltt_session *session,
-               struct lttng_domain *domain,
+               const struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
                char *filter_expression,
                struct lttng_filter_bytecode *filter,
@@ -395,95 +395,69 @@ end:
        }
 }
 
-static int increment_extended_len(const char *filter_expression,
-               struct lttng_event_exclusion *exclusion,
-               const struct lttng_userspace_probe_location *probe_location,
-               size_t *extended_len)
-{
-       int ret = 0;
-
-       *extended_len += sizeof(struct lttcomm_event_extended_header);
-
-       if (filter_expression) {
-               *extended_len += strlen(filter_expression) + 1;
-       }
-
-       if (exclusion) {
-               *extended_len += exclusion->count * LTTNG_SYMBOL_NAME_LEN;
-       }
-
-       if (probe_location) {
-               ret = lttng_userspace_probe_location_serialize(probe_location,
-                               NULL, NULL);
-               if (ret < 0) {
-                       goto end;
-               }
-               *extended_len += ret;
-       }
-       ret = 0;
-end:
-       return ret;
-}
-
 static int append_extended_info(const char *filter_expression,
                struct lttng_event_exclusion *exclusion,
                struct lttng_userspace_probe_location *probe_location,
-               void **extended_at)
+               struct lttng_payload *payload)
 {
        int ret = 0;
        size_t filter_len = 0;
        size_t nb_exclusions = 0;
        size_t userspace_probe_location_len = 0;
-       struct lttng_dynamic_buffer location_buffer;
-       struct lttcomm_event_extended_header extended_header;
+       struct lttcomm_event_extended_header extended_header = {};
+       struct lttcomm_event_extended_header *p_extended_header;
+       const size_t original_payload_size = payload->buffer.size;
+
+       ret = lttng_dynamic_buffer_append(&payload->buffer, &extended_header,
+                       sizeof(extended_header));
+       if (ret) {
+               goto end;
+       }
 
        if (filter_expression) {
                filter_len = strlen(filter_expression) + 1;
+               ret = lttng_dynamic_buffer_append(&payload->buffer,
+                               filter_expression, filter_len);
+               if (ret) {
+                       goto end;
+               }
        }
 
        if (exclusion) {
+               const size_t len = exclusion->count * LTTNG_SYMBOL_NAME_LEN;
+
                nb_exclusions = exclusion->count;
+
+               ret = lttng_dynamic_buffer_append(
+                               &payload->buffer, &exclusion->names, len);
+               if (ret) {
+                       goto end;
+               }
        }
 
        if (probe_location) {
-               lttng_dynamic_buffer_init(&location_buffer);
+               const size_t size_before_probe = payload->buffer.size;
+
                ret = lttng_userspace_probe_location_serialize(probe_location,
-                               &location_buffer, NULL);
+                               payload);
                if (ret < 0) {
                        ret = -1;
                        goto end;
                }
-               userspace_probe_location_len = location_buffer.size;
-       }
-
-       /* Set header fields */
-       extended_header.filter_len = filter_len;
-       extended_header.nb_exclusions = nb_exclusions;
-       extended_header.userspace_probe_location_len = userspace_probe_location_len;
-
-       /* Copy header */
-       memcpy(*extended_at, &extended_header, sizeof(extended_header));
-       *extended_at += sizeof(extended_header);
 
-       /* Copy filter string */
-       if (filter_expression) {
-               memcpy(*extended_at, filter_expression, filter_len);
-               *extended_at += filter_len;
+               userspace_probe_location_len =
+                               payload->buffer.size - size_before_probe;
        }
 
-       /* Copy exclusion names */
-       if (exclusion) {
-               size_t len = nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+       /* Set header fields */
+       p_extended_header = (struct lttcomm_event_extended_header *)
+                       (payload->buffer.data + original_payload_size);
 
-               memcpy(*extended_at, &exclusion->names, len);
-               *extended_at += len;
-       }
+       p_extended_header->filter_len = filter_len;
+       p_extended_header->nb_exclusions = nb_exclusions;
+       p_extended_header->userspace_probe_location_len =
+                       userspace_probe_location_len;
 
-       if (probe_location) {
-               memcpy(*extended_at, location_buffer.data, location_buffer.size);
-               *extended_at += location_buffer.size;
-               lttng_dynamic_buffer_reset(&location_buffer);
-       }
        ret = 0;
 end:
        return ret;
@@ -495,89 +469,55 @@ end:
  * Return number of events in list on success or else a negative value.
  */
 static int list_lttng_agent_events(struct agent *agt,
-               struct lttng_event **events, size_t *total_size)
+               struct lttng_payload *payload)
 {
-       int i = 0, ret = 0;
-       unsigned int nb_event = 0;
-       struct agent_event *event;
-       struct lttng_event *tmp_events = NULL;
+       int nb_events = 0, ret = 0;
+       const struct agent_event *agent_event;
        struct lttng_ht_iter iter;
-       size_t extended_len = 0;
-       void *extended_at;
 
        assert(agt);
-       assert(events);
 
        DBG3("Listing agent events");
 
        rcu_read_lock();
-       nb_event = lttng_ht_get_count(agt->events);
-       rcu_read_unlock();
-       if (nb_event == 0) {
-               ret = nb_event;
-               *total_size = 0;
-               goto error;
-       }
-
-       /* Compute required extended infos size */
-       extended_len = nb_event * sizeof(struct lttcomm_event_extended_header);
-
-       /*
-        * This is only valid because the commands which add events are
-        * processed in the same thread as the listing.
-        */
-       rcu_read_lock();
-       cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
-               ret = increment_extended_len(event->filter_expression, NULL, NULL,
-                               &extended_len);
+       cds_lfht_for_each_entry (
+                       agt->events->ht, &iter.iter, agent_event, node.node) {
+               struct lttng_event event = {
+                       .enabled = agent_event->enabled,
+                       .loglevel = agent_event->loglevel_value,
+                       .loglevel_type = agent_event->loglevel_type,
+               };
+
+               strncpy(event.name, agent_event->name, sizeof(event.name));
+               event.name[sizeof(event.name) - 1] = '\0';
+
+               ret = lttng_dynamic_buffer_append(
+                               &payload->buffer, &event, sizeof(event));
                if (ret) {
-                       DBG("Error computing the length of extended info message");
-                       ret = -LTTNG_ERR_FATAL;
-                       goto error;
+                       ERR("Failed to append event to payload");
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
                }
-       }
-       rcu_read_unlock();
 
-       *total_size = nb_event * sizeof(*tmp_events) + extended_len;
-       tmp_events = zmalloc(*total_size);
-       if (!tmp_events) {
-               PERROR("zmalloc agent events session");
-               ret = -LTTNG_ERR_FATAL;
-               goto error;
+               nb_events++;
        }
 
-       extended_at = ((uint8_t *) tmp_events) +
-               nb_event * sizeof(struct lttng_event);
-
-       rcu_read_lock();
-       cds_lfht_for_each_entry(agt->events->ht, &iter.iter, event, node.node) {
-               strncpy(tmp_events[i].name, event->name, sizeof(tmp_events[i].name));
-               tmp_events[i].name[sizeof(tmp_events[i].name) - 1] = '\0';
-               tmp_events[i].enabled = event->enabled;
-               tmp_events[i].loglevel = event->loglevel_value;
-               tmp_events[i].loglevel_type = event->loglevel_type;
-               i++;
-
-               /* Append extended info */
-               ret = append_extended_info(event->filter_expression, NULL, NULL,
-                               &extended_at);
+       cds_lfht_for_each_entry (
+               agt->events->ht, &iter.iter, agent_event, node.node) {
+               /* Append extended info. */
+               ret = append_extended_info(agent_event->filter_expression, NULL,
+                               NULL, payload);
                if (ret) {
-                       DBG("Error appending extended info message");
-                       ret = -LTTNG_ERR_FATAL;
-                       goto error;
+                       ERR("Failed to append extended event info to payload");
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
                }
        }
 
-       *events = tmp_events;
-       ret = nb_event;
-       assert(nb_event == i);
-
+       ret = nb_events;
 end:
        rcu_read_unlock();
        return ret;
-error:
-       free(tmp_events);
-       goto end;
 }
 
 /*
@@ -585,23 +525,20 @@ error:
  */
 static int list_lttng_ust_global_events(char *channel_name,
                struct ltt_ust_domain_global *ust_global,
-               struct lttng_event **events, size_t *total_size)
+               struct lttng_payload *payload)
 {
-       int i = 0, ret = 0;
-       unsigned int nb_event = 0;
+       int ret = 0;
+       unsigned int nb_events = 0;
        struct lttng_ht_iter iter;
-       struct lttng_ht_node_str *node;
-       struct ltt_ust_channel *uchan;
-       struct ltt_ust_event *uevent;
-       struct lttng_event *tmp;
-       size_t extended_len = 0;
-       void *extended_at;
+       const struct lttng_ht_node_str *node;
+       const struct ltt_ust_channel *uchan;
+       const struct ltt_ust_event *uevent;
 
        DBG("Listing UST global events for channel %s", channel_name);
 
        rcu_read_lock();
 
-       lttng_ht_lookup(ust_global->channels, (void *)channel_name, &iter);
+       lttng_ht_lookup(ust_global->channels, (void *) channel_name, &iter);
        node = lttng_ht_iter_get_node_str(&iter);
        if (node == NULL) {
                ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
@@ -610,99 +547,75 @@ static int list_lttng_ust_global_events(char *channel_name,
 
        uchan = caa_container_of(&node->node, struct ltt_ust_channel, node.node);
 
-       nb_event = lttng_ht_get_count(uchan->events);
-       if (nb_event == 0) {
-               ret = nb_event;
-               *total_size = 0;
-               goto end;
-       }
-
-       DBG3("Listing UST global %d events", nb_event);
+       DBG3("Listing UST global events");
 
-       /* Compute required extended infos size */
        cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
+               struct lttng_event event = {};
+
                if (uevent->internal) {
-                       nb_event--;
                        continue;
                }
 
-               ret = increment_extended_len(uevent->filter_expression,
-                       uevent->exclusion, NULL, &extended_len);
-               if (ret) {
-                       DBG("Error computing the length of extended info message");
-                       ret = -LTTNG_ERR_FATAL;
-                       goto end;
-               }
-       }
-       if (nb_event == 0) {
-               /* All events are internal, skip. */
-               ret = 0;
-               *total_size = 0;
-               goto end;
-       }
-
-       *total_size = nb_event * sizeof(struct lttng_event) + extended_len;
-       tmp = zmalloc(*total_size);
-       if (tmp == NULL) {
-               ret = -LTTNG_ERR_FATAL;
-               goto end;
-       }
-
-       extended_at = ((uint8_t *) tmp) + nb_event * sizeof(struct lttng_event);
+               strncpy(event.name, uevent->attr.name, sizeof(event.name));
+               event.name[sizeof(event.name) - 1] = '\0';
 
-       cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
-               if (uevent->internal) {
-                       /* This event should remain hidden from clients */
-                       continue;
-               }
-               strncpy(tmp[i].name, uevent->attr.name, LTTNG_SYMBOL_NAME_LEN);
-               tmp[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
-               tmp[i].enabled = uevent->enabled;
+               event.enabled = uevent->enabled;
 
                switch (uevent->attr.instrumentation) {
                case LTTNG_UST_TRACEPOINT:
-                       tmp[i].type = LTTNG_EVENT_TRACEPOINT;
+                       event.type = LTTNG_EVENT_TRACEPOINT;
                        break;
                case LTTNG_UST_PROBE:
-                       tmp[i].type = LTTNG_EVENT_PROBE;
+                       event.type = LTTNG_EVENT_PROBE;
                        break;
                case LTTNG_UST_FUNCTION:
-                       tmp[i].type = LTTNG_EVENT_FUNCTION;
+                       event.type = LTTNG_EVENT_FUNCTION;
                        break;
                }
 
-               tmp[i].loglevel = uevent->attr.loglevel;
+               event.loglevel = uevent->attr.loglevel;
                switch (uevent->attr.loglevel_type) {
                case LTTNG_UST_LOGLEVEL_ALL:
-                       tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
+                       event.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
                        break;
                case LTTNG_UST_LOGLEVEL_RANGE:
-                       tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
+                       event.loglevel_type = LTTNG_EVENT_LOGLEVEL_RANGE;
                        break;
                case LTTNG_UST_LOGLEVEL_SINGLE:
-                       tmp[i].loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
+                       event.loglevel_type = LTTNG_EVENT_LOGLEVEL_SINGLE;
                        break;
                }
+
                if (uevent->filter) {
-                       tmp[i].filter = 1;
+                       event.filter = 1;
                }
+
                if (uevent->exclusion) {
-                       tmp[i].exclusion = 1;
+                       event.exclusion = 1;
                }
-               i++;
 
-               /* Append extended info */
+               ret = lttng_dynamic_buffer_append(&payload->buffer, &event, sizeof(event));
+               if (ret) {
+                       ERR("Failed to append event to payload");
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+
+               nb_events++;
+       }
+
+       cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent, node.node) {
+               /* Append extended info. */
                ret = append_extended_info(uevent->filter_expression,
-                       uevent->exclusion, NULL, &extended_at);
+                               uevent->exclusion, NULL, payload);
                if (ret) {
-                       DBG("Error appending extended info message");
+                       ERR("Failed to append extended event info to payload");
                        ret = -LTTNG_ERR_FATAL;
                        goto end;
                }
        }
 
-       ret = nb_event;
-       *events = tmp;
+       ret = nb_events;
 end:
        rcu_read_unlock();
        return ret;
@@ -713,14 +626,12 @@ end:
  */
 static int list_lttng_kernel_events(char *channel_name,
                struct ltt_kernel_session *kernel_session,
-               struct lttng_event **events, size_t *total_size)
+               struct lttng_payload *payload)
 {
-       int i = 0, ret;
+       int ret;
        unsigned int nb_event;
-       struct ltt_kernel_event *event;
-       struct ltt_kernel_channel *kchan;
-       size_t extended_len = 0;
-       void *extended_at;
+       const struct ltt_kernel_event *kevent;
+       const struct ltt_kernel_channel *kchan;
 
        kchan = trace_kernel_get_channel_by_name(channel_name, kernel_session);
        if (kchan == NULL) {
@@ -732,69 +643,42 @@ static int list_lttng_kernel_events(char *channel_name,
 
        DBG("Listing events for channel %s", kchan->channel->name);
 
-       if (nb_event == 0) {
-               *total_size = 0;
-               *events = NULL;
-               goto end;
-       }
-
-       /* Compute required extended infos size */
-       cds_list_for_each_entry(event, &kchan->events_list.head, list) {
-               ret = increment_extended_len(event->filter_expression, NULL,
-                       event->userspace_probe_location,
-                       &extended_len);
-               if (ret) {
-                       DBG("Error computing the length of extended info message");
-                       ret = -LTTNG_ERR_FATAL;
-                       goto error;
-               }
-       }
-
-       *total_size = nb_event * sizeof(struct lttng_event) + extended_len;
-       *events = zmalloc(*total_size);
-       if (*events == NULL) {
-               ret = -LTTNG_ERR_FATAL;
-               goto error;
-       }
+       /* Kernel channels */
+       cds_list_for_each_entry(kevent, &kchan->events_list.head , list) {
+               struct lttng_event event = {};
 
-       extended_at = ((void *) *events) +
-               nb_event * sizeof(struct lttng_event);
+               strncpy(event.name, kevent->event->name, sizeof(event.name));
+               event.name[sizeof(event.name) - 1] = '\0';
+               event.enabled = kevent->enabled;
+               event.filter = (unsigned char) !!kevent->filter_expression;
 
-       /* Kernel channels */
-       cds_list_for_each_entry(event, &kchan->events_list.head , list) {
-               strncpy((*events)[i].name, event->event->name, LTTNG_SYMBOL_NAME_LEN);
-               (*events)[i].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
-               (*events)[i].enabled = event->enabled;
-               (*events)[i].filter =
-                               (unsigned char) !!event->filter_expression;
-
-               switch (event->event->instrumentation) {
+               switch (kevent->event->instrumentation) {
                case LTTNG_KERNEL_TRACEPOINT:
-                       (*events)[i].type = LTTNG_EVENT_TRACEPOINT;
+                       event.type = LTTNG_EVENT_TRACEPOINT;
                        break;
                case LTTNG_KERNEL_KRETPROBE:
-                       (*events)[i].type = LTTNG_EVENT_FUNCTION;
-                       memcpy(&(*events)[i].attr.probe, &event->event->u.kprobe,
+                       event.type = LTTNG_EVENT_FUNCTION;
+                       memcpy(&event.attr.probe, &kevent->event->u.kprobe,
                                        sizeof(struct lttng_kernel_kprobe));
                        break;
                case LTTNG_KERNEL_KPROBE:
-                       (*events)[i].type = LTTNG_EVENT_PROBE;
-                       memcpy(&(*events)[i].attr.probe, &event->event->u.kprobe,
+                       event.type = LTTNG_EVENT_PROBE;
+                       memcpy(&event.attr.probe, &kevent->event->u.kprobe,
                                        sizeof(struct lttng_kernel_kprobe));
                        break;
                case LTTNG_KERNEL_UPROBE:
-                       (*events)[i].type = LTTNG_EVENT_USERSPACE_PROBE;
+                       event.type = LTTNG_EVENT_USERSPACE_PROBE;
                        break;
                case LTTNG_KERNEL_FUNCTION:
-                       (*events)[i].type = LTTNG_EVENT_FUNCTION;
-                       memcpy(&((*events)[i].attr.ftrace), &event->event->u.ftrace,
+                       event.type = LTTNG_EVENT_FUNCTION;
+                       memcpy(&event.attr.ftrace, &kevent->event->u.ftrace,
                                        sizeof(struct lttng_kernel_function));
                        break;
                case LTTNG_KERNEL_NOOP:
-                       (*events)[i].type = LTTNG_EVENT_NOOP;
+                       event.type = LTTNG_EVENT_NOOP;
                        break;
                case LTTNG_KERNEL_SYSCALL:
-                       (*events)[i].type = LTTNG_EVENT_SYSCALL;
+                       event.type = LTTNG_EVENT_SYSCALL;
                        break;
                case LTTNG_KERNEL_ALL:
                        /* fall-through. */
@@ -802,11 +686,20 @@ static int list_lttng_kernel_events(char *channel_name,
                        assert(0);
                        break;
                }
-               i++;
 
-               /* Append extended info */
-               ret = append_extended_info(event->filter_expression, NULL,
-                       event->userspace_probe_location, &extended_at);
+               ret = lttng_dynamic_buffer_append(
+                               &payload->buffer, &event, sizeof(event));
+               if (ret) {
+                       ERR("Failed to append event to payload");
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto end;
+               }
+       }
+
+       cds_list_for_each_entry(kevent, &kchan->events_list.head , list) {
+               /* Append extended info. */
+               ret = append_extended_info(kevent->filter_expression, NULL,
+                               kevent->userspace_probe_location, payload);
                if (ret) {
                        DBG("Error appending extended info message");
                        ret = -LTTNG_ERR_FATAL;
@@ -816,10 +709,8 @@ static int list_lttng_kernel_events(char *channel_name,
 
 end:
        return nb_event;
-
 error:
-       /* Negate the error code to differentiate the size from an error */
-       return -ret;
+       return ret;
 }
 
 /*
@@ -912,6 +803,10 @@ static enum lttng_error_code add_uri_to_consumer(
                ret = lttng_strncpy(consumer->dst.session_root_path,
                                uri->dst.path,
                                sizeof(consumer->dst.session_root_path));
+               if (ret) {
+                       ret_code = LTTNG_ERR_FATAL;
+                       goto error;
+               }
                consumer->type = CONSUMER_DST_LOCAL;
                break;
        }
@@ -989,6 +884,8 @@ static enum lttng_error_code create_connect_relayd(struct lttng_uri *uri,
 
        /* Create socket for control stream. */
        if (uri->stype == LTTNG_STREAM_CONTROL) {
+               uint64_t result_flags;
+
                DBG3("Creating relayd stream socket from URI");
 
                /* Check relayd version */
@@ -1003,6 +900,16 @@ static enum lttng_error_code create_connect_relayd(struct lttng_uri *uri,
                }
                consumer->relay_major_version = rsock->major;
                consumer->relay_minor_version = rsock->minor;
+               ret = relayd_get_configuration(rsock, 0,
+                               &result_flags);
+               if (ret < 0) {
+                       ERR("Unable to get relayd configuration");
+                       status = LTTNG_ERR_RELAYD_CONNECT_FAIL;
+                       goto close_sock;
+               }
+               if (result_flags & LTTCOMM_RELAYD_CONFIGURATION_FLAG_CLEAR_ALLOWED) {
+                       consumer->relay_allows_clear = true;
+               }
        } else if (uri->stype == LTTNG_STREAM_DATA) {
                DBG3("Creating relayd data socket from URI");
        } else {
@@ -1038,8 +945,10 @@ static enum lttng_error_code send_consumer_relayd_socket(
                struct consumer_output *consumer,
                struct consumer_socket *consumer_sock,
                const char *session_name, const char *hostname,
-               int session_live_timer,
-               const uint64_t *current_chunk_id)
+               const char *base_path, int session_live_timer,
+               const uint64_t *current_chunk_id,
+               time_t session_creation_time,
+               bool session_name_contains_creation_time)
 {
        int ret;
        struct lttcomm_relayd_sock *rsock = NULL;
@@ -1067,8 +976,9 @@ static enum lttng_error_code send_consumer_relayd_socket(
        /* Send relayd socket to consumer. */
        ret = consumer_send_relayd_socket(consumer_sock, rsock, consumer,
                        relayd_uri->stype, session_id,
-                       session_name, hostname, session_live_timer,
-                       current_chunk_id);
+                       session_name, hostname, base_path,
+                       session_live_timer, current_chunk_id,
+                       session_creation_time, session_name_contains_creation_time);
        if (ret < 0) {
                status = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
                goto close_sock;
@@ -1115,8 +1025,9 @@ static enum lttng_error_code send_consumer_relayd_sockets(
                enum lttng_domain_type domain,
                unsigned int session_id, struct consumer_output *consumer,
                struct consumer_socket *sock, const char *session_name,
-               const char *hostname, int session_live_timer,
-               const uint64_t *current_chunk_id)
+               const char *hostname, const char *base_path, int session_live_timer,
+               const uint64_t *current_chunk_id, time_t session_creation_time,
+               bool session_name_contains_creation_time)
 {
        enum lttng_error_code status = LTTNG_OK;
 
@@ -1127,8 +1038,9 @@ static enum lttng_error_code send_consumer_relayd_sockets(
        if (!sock->control_sock_sent) {
                status = send_consumer_relayd_socket(session_id,
                                &consumer->dst.net.control, consumer, sock,
-                               session_name, hostname, session_live_timer,
-                               current_chunk_id);
+                               session_name, hostname, base_path, session_live_timer,
+                               current_chunk_id, session_creation_time,
+                               session_name_contains_creation_time);
                if (status != LTTNG_OK) {
                        goto error;
                }
@@ -1138,8 +1050,9 @@ static enum lttng_error_code send_consumer_relayd_sockets(
        if (!sock->data_sock_sent) {
                status = send_consumer_relayd_socket(session_id,
                                &consumer->dst.net.data, consumer, sock,
-                               session_name, hostname, session_live_timer,
-                               current_chunk_id);
+                               session_name, hostname, base_path, session_live_timer,
+                               current_chunk_id, session_creation_time,
+                               session_name_contains_creation_time);
                if (status != LTTNG_OK) {
                        goto error;
                }
@@ -1161,15 +1074,16 @@ int cmd_setup_relayd(struct ltt_session *session)
        struct ltt_kernel_session *ksess;
        struct consumer_socket *socket;
        struct lttng_ht_iter iter;
-        LTTNG_OPTIONAL(uint64_t) current_chunk_id = {};
+       LTTNG_OPTIONAL(uint64_t) current_chunk_id = {};
 
-        assert(session);
+       assert(session);
 
        usess = session->ust_session;
        ksess = session->kernel_session;
 
        DBG("Setting relayd for session %s", session->name);
 
+       rcu_read_lock();
        if (session->current_trace_chunk) {
                enum lttng_trace_chunk_status status = lttng_trace_chunk_get_id(
                                session->current_trace_chunk, &current_chunk_id.value);
@@ -1183,8 +1097,6 @@ int cmd_setup_relayd(struct ltt_session *session)
                }
        }
 
-       rcu_read_lock();
-
        if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
                        && usess->consumer->enabled) {
                /* For each consumer socket, send relayd sockets */
@@ -1194,8 +1106,11 @@ int cmd_setup_relayd(struct ltt_session *session)
                        ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session->id,
                                        usess->consumer, socket,
                                        session->name, session->hostname,
+                                       session->base_path,
                                        session->live_timer,
-                                       current_chunk_id.is_set ? &current_chunk_id.value : NULL);
+                                       current_chunk_id.is_set ? &current_chunk_id.value : NULL,
+                                       session->creation_time,
+                                       session->name_contains_creation_time);
                        pthread_mutex_unlock(socket->lock);
                        if (ret != LTTNG_OK) {
                                goto error;
@@ -1207,6 +1122,8 @@ int cmd_setup_relayd(struct ltt_session *session)
                        usess->consumer->relay_major_version;
                session->consumer->relay_minor_version =
                        usess->consumer->relay_minor_version;
+               session->consumer->relay_allows_clear =
+                       usess->consumer->relay_allows_clear;
        }
 
        if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
@@ -1217,8 +1134,11 @@ int cmd_setup_relayd(struct ltt_session *session)
                        ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session->id,
                                        ksess->consumer, socket,
                                        session->name, session->hostname,
+                                       session->base_path,
                                        session->live_timer,
-                                       current_chunk_id.is_set ? &current_chunk_id.value : NULL);
+                                       current_chunk_id.is_set ? &current_chunk_id.value : NULL,
+                                       session->creation_time,
+                                       session->name_contains_creation_time);
                        pthread_mutex_unlock(socket->lock);
                        if (ret != LTTNG_OK) {
                                goto error;
@@ -1230,6 +1150,8 @@ int cmd_setup_relayd(struct ltt_session *session)
                        ksess->consumer->relay_major_version;
                session->consumer->relay_minor_version =
                        ksess->consumer->relay_minor_version;
+               session->consumer->relay_allows_clear =
+                       ksess->consumer->relay_allows_clear;
        }
 
 error:
@@ -1240,7 +1162,7 @@ error:
 /*
  * Start a kernel session by opening all necessary streams.
  */
-static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
+int start_kernel_session(struct ltt_kernel_session *ksess)
 {
        int ret;
        struct ltt_kernel_channel *kchan;
@@ -1292,7 +1214,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
        }
 
        /* Quiescent wait after starting trace */
-       kernel_wait_quiescent(wpipe);
+       kernel_wait_quiescent();
 
        ksess->active = 1;
 
@@ -1302,147 +1224,92 @@ error:
        return ret;
 }
 
-/*
- * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
- */
-int cmd_disable_channel(struct ltt_session *session,
-               enum lttng_domain_type domain, char *channel_name)
+int stop_kernel_session(struct ltt_kernel_session *ksess)
 {
+       struct ltt_kernel_channel *kchan;
+       bool error_occurred = false;
        int ret;
-       struct ltt_ust_session *usess;
-
-       usess = session->ust_session;
-
-       rcu_read_lock();
-
-       switch (domain) {
-       case LTTNG_DOMAIN_KERNEL:
-       {
-               ret = channel_kernel_disable(session->kernel_session,
-                               channel_name);
-               if (ret != LTTNG_OK) {
-                       goto error;
-               }
 
-               kernel_wait_quiescent(kernel_tracer_fd);
-               break;
+       if (!ksess || !ksess->active) {
+               return LTTNG_OK;
        }
-       case LTTNG_DOMAIN_UST:
-       {
-               struct ltt_ust_channel *uchan;
-               struct lttng_ht *chan_ht;
-
-               chan_ht = usess->domain_global.channels;
+       DBG("Stopping kernel tracing");
 
-               uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
-               if (uchan == NULL) {
-                       ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
-                       goto error;
-               }
-
-               ret = channel_ust_disable(usess, uchan);
-               if (ret != LTTNG_OK) {
-                       goto error;
-               }
-               break;
-       }
-       default:
-               ret = LTTNG_ERR_UNKNOWN_DOMAIN;
+       ret = kernel_stop_session(ksess);
+       if (ret < 0) {
+               ret = LTTNG_ERR_KERN_STOP_FAIL;
                goto error;
        }
 
-       ret = LTTNG_OK;
-
-error:
-       rcu_read_unlock();
-       return ret;
-}
+       kernel_wait_quiescent();
 
-/*
- * Command LTTNG_TRACK_PID processed by the client thread.
- *
- * Called with session lock held.
- */
-int cmd_track_pid(struct ltt_session *session, enum lttng_domain_type domain,
-               int pid)
-{
-       int ret;
-
-       rcu_read_lock();
-
-       switch (domain) {
-       case LTTNG_DOMAIN_KERNEL:
-       {
-               struct ltt_kernel_session *ksess;
-
-               ksess = session->kernel_session;
-
-               ret = kernel_track_pid(ksess, pid);
-               if (ret != LTTNG_OK) {
-                       goto error;
+       /* Flush metadata after stopping (if exists) */
+       if (ksess->metadata_stream_fd >= 0) {
+               ret = kernel_metadata_flush_buffer(ksess->metadata_stream_fd);
+               if (ret < 0) {
+                       ERR("Kernel metadata flush failed");
+                       error_occurred = true;
                }
-
-               kernel_wait_quiescent(kernel_tracer_fd);
-               break;
        }
-       case LTTNG_DOMAIN_UST:
-       {
-               struct ltt_ust_session *usess;
-
-               usess = session->ust_session;
 
-               ret = trace_ust_track_pid(usess, pid);
-               if (ret != LTTNG_OK) {
-                       goto error;
+       /* Flush all buffers after stopping */
+       cds_list_for_each_entry(kchan, &ksess->channel_list.head, list) {
+               ret = kernel_flush_buffer(kchan);
+               if (ret < 0) {
+                       ERR("Kernel flush buffer error");
+                       error_occurred = true;
                }
-               break;
-       }
-       default:
-               ret = LTTNG_ERR_UNKNOWN_DOMAIN;
-               goto error;
        }
 
-       ret = LTTNG_OK;
-
+       ksess->active = 0;
+       if (error_occurred) {
+               ret = LTTNG_ERR_UNK;
+       } else {
+               ret = LTTNG_OK;
+       }
 error:
-       rcu_read_unlock();
        return ret;
 }
 
 /*
- * Command LTTNG_UNTRACK_PID processed by the client thread.
- *
- * Called with session lock held.
+ * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
  */
-int cmd_untrack_pid(struct ltt_session *session, enum lttng_domain_type domain,
-               int pid)
+int cmd_disable_channel(struct ltt_session *session,
+               enum lttng_domain_type domain, char *channel_name)
 {
        int ret;
+       struct ltt_ust_session *usess;
+
+       usess = session->ust_session;
 
        rcu_read_lock();
 
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
        {
-               struct ltt_kernel_session *ksess;
-
-               ksess = session->kernel_session;
-
-               ret = kernel_untrack_pid(ksess, pid);
+               ret = channel_kernel_disable(session->kernel_session,
+                               channel_name);
                if (ret != LTTNG_OK) {
                        goto error;
                }
 
-               kernel_wait_quiescent(kernel_tracer_fd);
+               kernel_wait_quiescent();
                break;
        }
        case LTTNG_DOMAIN_UST:
        {
-               struct ltt_ust_session *usess;
+               struct ltt_ust_channel *uchan;
+               struct lttng_ht *chan_ht;
 
-               usess = session->ust_session;
+               chan_ht = usess->domain_global.channels;
 
-               ret = trace_ust_untrack_pid(usess, pid);
+               uchan = trace_ust_find_channel_by_name(chan_ht, channel_name);
+               if (uchan == NULL) {
+                       ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+                       goto error;
+               }
+
+               ret = channel_ust_disable(usess, uchan);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -1466,27 +1333,29 @@ error:
  * The wpipe arguments is used as a notifier for the kernel thread.
  */
 int cmd_enable_channel(struct ltt_session *session,
-               struct lttng_domain *domain, struct lttng_channel *attr, int wpipe)
+               const struct lttng_domain *domain, const struct lttng_channel *_attr, int wpipe)
 {
        int ret;
        struct ltt_ust_session *usess = session->ust_session;
        struct lttng_ht *chan_ht;
        size_t len;
+       struct lttng_channel attr;
 
        assert(session);
-       assert(attr);
+       assert(_attr);
        assert(domain);
 
-       len = lttng_strnlen(attr->name, sizeof(attr->name));
+       attr = *_attr;
+       len = lttng_strnlen(attr.name, sizeof(attr.name));
 
        /* Validate channel name */
-       if (attr->name[0] == '.' ||
-               memchr(attr->name, '/', len) != NULL) {
+       if (attr.name[0] == '.' ||
+               memchr(attr.name, '/', len) != NULL) {
                ret = LTTNG_ERR_INVALID_CHANNEL_NAME;
                goto end;
        }
 
-       DBG("Enabling channel %s for session %s", attr->name, session->name);
+       DBG("Enabling channel %s for session %s", attr.name, session->name);
 
        rcu_read_lock();
 
@@ -1505,21 +1374,21 @@ int cmd_enable_channel(struct ltt_session *session,
         * beacons for inactive streams.
         */
        if (session->live_timer > 0) {
-               attr->attr.live_timer_interval = session->live_timer;
-               attr->attr.switch_timer_interval = 0;
+               attr.attr.live_timer_interval = session->live_timer;
+               attr.attr.switch_timer_interval = 0;
        }
 
        /* Check for feature support */
        switch (domain->type) {
        case LTTNG_DOMAIN_KERNEL:
        {
-               if (kernel_supports_ring_buffer_snapshot_sample_positions(kernel_tracer_fd) != 1) {
+               if (kernel_supports_ring_buffer_snapshot_sample_positions() != 1) {
                        /* Sampling position of buffer is not supported */
                        WARN("Kernel tracer does not support buffer monitoring. "
                                        "Setting the monitor interval timer to 0 "
                                        "(disabled) for channel '%s' of session '%s'",
-                                       attr-> name, session->name);
-                       lttng_channel_set_monitor_timer_interval(attr, 0);
+                                       attr.name, session->name);
+                       lttng_channel_set_monitor_timer_interval(&attr, 0);
                }
                break;
        }
@@ -1544,16 +1413,16 @@ int cmd_enable_channel(struct ltt_session *session,
        {
                struct ltt_kernel_channel *kchan;
 
-               kchan = trace_kernel_get_channel_by_name(attr->name,
+               kchan = trace_kernel_get_channel_by_name(attr.name,
                                session->kernel_session);
                if (kchan == NULL) {
                        if (session->snapshot.nb_output > 0 ||
                                        session->snapshot_mode) {
                                /* Enforce mmap output for snapshot sessions. */
-                               attr->attr.output = LTTNG_EVENT_MMAP;
+                               attr.attr.output = LTTNG_EVENT_MMAP;
                        }
-                       ret = channel_kernel_create(session->kernel_session, attr, wpipe);
-                       if (attr->name[0] != '\0') {
+                       ret = channel_kernel_create(session->kernel_session, &attr, wpipe);
+                       if (attr.name[0] != '\0') {
                                session->kernel_session->has_non_default_channel = 1;
                        }
                } else {
@@ -1564,7 +1433,7 @@ int cmd_enable_channel(struct ltt_session *session,
                        goto error;
                }
 
-               kernel_wait_quiescent(kernel_tracer_fd);
+               kernel_wait_quiescent();
                break;
        }
        case LTTNG_DOMAIN_UST:
@@ -1583,19 +1452,19 @@ int cmd_enable_channel(struct ltt_session *session,
                 * adhered to.
                 */
                if (domain->type == LTTNG_DOMAIN_JUL) {
-                       if (strncmp(attr->name, DEFAULT_JUL_CHANNEL_NAME,
+                       if (strncmp(attr.name, DEFAULT_JUL_CHANNEL_NAME,
                                        LTTNG_SYMBOL_NAME_LEN)) {
                                ret = LTTNG_ERR_INVALID_CHANNEL_NAME;
                                goto error;
                        }
                } else if (domain->type == LTTNG_DOMAIN_LOG4J) {
-                       if (strncmp(attr->name, DEFAULT_LOG4J_CHANNEL_NAME,
+                       if (strncmp(attr.name, DEFAULT_LOG4J_CHANNEL_NAME,
                                        LTTNG_SYMBOL_NAME_LEN)) {
                                ret = LTTNG_ERR_INVALID_CHANNEL_NAME;
                                goto error;
                        }
                } else if (domain->type == LTTNG_DOMAIN_PYTHON) {
-                       if (strncmp(attr->name, DEFAULT_PYTHON_CHANNEL_NAME,
+                       if (strncmp(attr.name, DEFAULT_PYTHON_CHANNEL_NAME,
                                        LTTNG_SYMBOL_NAME_LEN)) {
                                ret = LTTNG_ERR_INVALID_CHANNEL_NAME;
                                goto error;
@@ -1604,10 +1473,10 @@ int cmd_enable_channel(struct ltt_session *session,
 
                chan_ht = usess->domain_global.channels;
 
-               uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
+               uchan = trace_ust_find_channel_by_name(chan_ht, attr.name);
                if (uchan == NULL) {
-                       ret = channel_ust_create(usess, attr, domain->buf_type);
-                       if (attr->name[0] != '\0') {
+                       ret = channel_ust_create(usess, &attr, domain->buf_type);
+                       if (attr.name[0] != '\0') {
                                usess->has_non_default_channel = 1;
                        }
                } else {
@@ -1620,7 +1489,7 @@ int cmd_enable_channel(struct ltt_session *session,
                goto error;
        }
 
-       if (ret == LTTNG_OK && attr->attr.output != LTTNG_EVENT_MMAP) {
+       if (ret == LTTNG_OK && attr.attr.output != LTTNG_EVENT_MMAP) {
                session->has_non_mmap_channel = true;
        }
 error:
@@ -1629,15 +1498,220 @@ end:
        return ret;
 }
 
+enum lttng_error_code cmd_process_attr_tracker_get_tracking_policy(
+               struct ltt_session *session,
+               enum lttng_domain_type domain,
+               enum lttng_process_attr process_attr,
+               enum lttng_tracking_policy *policy)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+       const struct process_attr_tracker *tracker;
+
+       switch (domain) {
+       case LTTNG_DOMAIN_KERNEL:
+               if (!session->kernel_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               tracker = kernel_get_process_attr_tracker(
+                               session->kernel_session, process_attr);
+               break;
+       case LTTNG_DOMAIN_UST:
+               if (!session->ust_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               tracker = trace_ust_get_process_attr_tracker(
+                               session->ust_session, process_attr);
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNSUPPORTED_DOMAIN;
+               goto end;
+       }
+       if (tracker) {
+               *policy = process_attr_tracker_get_tracking_policy(tracker);
+       } else {
+               ret_code = LTTNG_ERR_INVALID;
+       }
+end:
+       return ret_code;
+}
+
+enum lttng_error_code cmd_process_attr_tracker_set_tracking_policy(
+               struct ltt_session *session,
+               enum lttng_domain_type domain,
+               enum lttng_process_attr process_attr,
+               enum lttng_tracking_policy policy)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+
+       switch (policy) {
+       case LTTNG_TRACKING_POLICY_INCLUDE_SET:
+       case LTTNG_TRACKING_POLICY_EXCLUDE_ALL:
+       case LTTNG_TRACKING_POLICY_INCLUDE_ALL:
+               break;
+       default:
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
+       }
+
+       switch (domain) {
+       case LTTNG_DOMAIN_KERNEL:
+               if (!session->kernel_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = kernel_process_attr_tracker_set_tracking_policy(
+                               session->kernel_session, process_attr, policy);
+               break;
+       case LTTNG_DOMAIN_UST:
+               if (!session->ust_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = trace_ust_process_attr_tracker_set_tracking_policy(
+                               session->ust_session, process_attr, policy);
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNSUPPORTED_DOMAIN;
+               break;
+       }
+end:
+       return ret_code;
+}
+
+enum lttng_error_code cmd_process_attr_tracker_inclusion_set_add_value(
+               struct ltt_session *session,
+               enum lttng_domain_type domain,
+               enum lttng_process_attr process_attr,
+               const struct process_attr_value *value)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+
+       switch (domain) {
+       case LTTNG_DOMAIN_KERNEL:
+               if (!session->kernel_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = kernel_process_attr_tracker_inclusion_set_add_value(
+                               session->kernel_session, process_attr, value);
+               break;
+       case LTTNG_DOMAIN_UST:
+               if (!session->ust_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = trace_ust_process_attr_tracker_inclusion_set_add_value(
+                               session->ust_session, process_attr, value);
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNSUPPORTED_DOMAIN;
+               break;
+       }
+end:
+       return ret_code;
+}
+
+enum lttng_error_code cmd_process_attr_tracker_inclusion_set_remove_value(
+               struct ltt_session *session,
+               enum lttng_domain_type domain,
+               enum lttng_process_attr process_attr,
+               const struct process_attr_value *value)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+
+       switch (domain) {
+       case LTTNG_DOMAIN_KERNEL:
+               if (!session->kernel_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = kernel_process_attr_tracker_inclusion_set_remove_value(
+                               session->kernel_session, process_attr, value);
+               break;
+       case LTTNG_DOMAIN_UST:
+               if (!session->ust_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               ret_code = trace_ust_process_attr_tracker_inclusion_set_remove_value(
+                               session->ust_session, process_attr, value);
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNSUPPORTED_DOMAIN;
+               break;
+       }
+end:
+       return ret_code;
+}
+
+enum lttng_error_code cmd_process_attr_tracker_get_inclusion_set(
+               struct ltt_session *session,
+               enum lttng_domain_type domain,
+               enum lttng_process_attr process_attr,
+               struct lttng_process_attr_values **values)
+{
+       enum lttng_error_code ret_code = LTTNG_OK;
+       const struct process_attr_tracker *tracker;
+       enum process_attr_tracker_status status;
+
+       switch (domain) {
+       case LTTNG_DOMAIN_KERNEL:
+               if (!session->kernel_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               tracker = kernel_get_process_attr_tracker(
+                               session->kernel_session, process_attr);
+               break;
+       case LTTNG_DOMAIN_UST:
+               if (!session->ust_session) {
+                       ret_code = LTTNG_ERR_INVALID;
+                       goto end;
+               }
+               tracker = trace_ust_get_process_attr_tracker(
+                               session->ust_session, process_attr);
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNSUPPORTED_DOMAIN;
+               goto end;
+       }
+
+       if (!tracker) {
+               ret_code = LTTNG_ERR_INVALID;
+               goto end;
+       }
+
+       status = process_attr_tracker_get_inclusion_set(tracker, values);
+       switch (status) {
+       case PROCESS_ATTR_TRACKER_STATUS_OK:
+               ret_code = LTTNG_OK;
+               break;
+       case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
+               ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
+               break;
+       case PROCESS_ATTR_TRACKER_STATUS_ERROR:
+               ret_code = LTTNG_ERR_NOMEM;
+               break;
+       default:
+               ret_code = LTTNG_ERR_UNK;
+               break;
+       }
+
+end:
+       return ret_code;
+}
+
 /*
  * Command LTTNG_DISABLE_EVENT processed by the client thread.
  */
 int cmd_disable_event(struct ltt_session *session,
-               enum lttng_domain_type domain, char *channel_name,
-               struct lttng_event *event)
+               enum lttng_domain_type domain, const char *channel_name,
+               const struct lttng_event *event)
 {
        int ret;
-       char *event_name;
+       const char *event_name;
 
        DBG("Disable event command for event \'%s\'", event->name);
 
@@ -1699,7 +1773,7 @@ int cmd_disable_event(struct ltt_session *session,
                        goto error_unlock;
                }
 
-               kernel_wait_quiescent(kernel_tracer_fd);
+               kernel_wait_quiescent();
                break;
        }
        case LTTNG_DOMAIN_UST:
@@ -1810,7 +1884,7 @@ error:
  * Command LTTNG_ADD_CONTEXT processed by the client thread.
  */
 int cmd_add_context(struct ltt_session *session, enum lttng_domain_type domain,
-               char *channel_name, struct lttng_event_context *ctx, int kwpipe)
+               char *channel_name, const struct lttng_event_context *ctx, int kwpipe)
 {
        int ret, chan_kern_created = 0, chan_ust_created = 0;
        char *app_ctx_provider_name = NULL, *app_ctx_name = NULL;
@@ -1981,7 +2055,7 @@ end:
  * enable the events through which all "agent" events are funeled.
  */
 static int _cmd_enable_event(struct ltt_session *session,
-               struct lttng_domain *domain,
+               const struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
                char *filter_expression,
                struct lttng_filter_bytecode *filter,
@@ -2149,7 +2223,7 @@ static int _cmd_enable_event(struct ltt_session *session,
                        goto error;
                }
 
-               kernel_wait_quiescent(kernel_tracer_fd);
+               kernel_wait_quiescent();
                break;
        }
        case LTTNG_DOMAIN_UST:
@@ -2214,7 +2288,7 @@ static int _cmd_enable_event(struct ltt_session *session,
                         */
                        ret = validate_ust_event_name(event->name);
                        if (ret) {
-                               WARN("Userspace event name %s failed validation.",
+                               WARN("Userspace event name %s failed validation.",
                                                event->name);
                                ret = LTTNG_ERR_INVALID_EVENT_NAME;
                                goto error;
@@ -2378,7 +2452,8 @@ error:
  * Command LTTNG_ENABLE_EVENT processed by the client thread.
  * We own filter, exclusion, and filter_expression.
  */
-int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
+int cmd_enable_event(struct ltt_session *session,
+               const struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
                char *filter_expression,
                struct lttng_filter_bytecode *filter,
@@ -2395,7 +2470,7 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
  * reserved names.
  */
 static int cmd_enable_event_internal(struct ltt_session *session,
-               struct lttng_domain *domain,
+               const struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
                char *filter_expression,
                struct lttng_filter_bytecode *filter,
@@ -2417,7 +2492,7 @@ ssize_t cmd_list_tracepoints(enum lttng_domain_type domain,
 
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
-               nb_events = kernel_list_events(kernel_tracer_fd, events);
+               nb_events = kernel_list_events(events);
                if (nb_events < 0) {
                        ret = LTTNG_ERR_KERN_LIST_FAIL;
                        goto error;
@@ -2486,57 +2561,6 @@ ssize_t cmd_list_syscalls(struct lttng_event **events)
        return syscall_table_list(events);
 }
 
-/*
- * Command LTTNG_LIST_TRACKER_PIDS processed by the client thread.
- *
- * Called with session lock held.
- */
-ssize_t cmd_list_tracker_pids(struct ltt_session *session,
-               enum lttng_domain_type domain, int32_t **pids)
-{
-       int ret;
-       ssize_t nr_pids = 0;
-
-       switch (domain) {
-       case LTTNG_DOMAIN_KERNEL:
-       {
-               struct ltt_kernel_session *ksess;
-
-               ksess = session->kernel_session;
-               nr_pids = kernel_list_tracker_pids(ksess, pids);
-               if (nr_pids < 0) {
-                       ret = LTTNG_ERR_KERN_LIST_FAIL;
-                       goto error;
-               }
-               break;
-       }
-       case LTTNG_DOMAIN_UST:
-       {
-               struct ltt_ust_session *usess;
-
-               usess = session->ust_session;
-               nr_pids = trace_ust_list_tracker_pids(usess, pids);
-               if (nr_pids < 0) {
-                       ret = LTTNG_ERR_UST_LIST_FAIL;
-                       goto error;
-               }
-               break;
-       }
-       case LTTNG_DOMAIN_LOG4J:
-       case LTTNG_DOMAIN_JUL:
-       case LTTNG_DOMAIN_PYTHON:
-       default:
-               ret = LTTNG_ERR_UND;
-               goto error;
-       }
-
-       return nr_pids;
-
-error:
-       /* Return negative value to differentiate return code */
-       return -ret;
-}
-
 /*
  * Command LTTNG_START_TRACE processed by the client thread.
  *
@@ -2548,6 +2572,10 @@ int cmd_start_trace(struct ltt_session *session)
        unsigned long nb_chan = 0;
        struct ltt_kernel_session *ksession;
        struct ltt_ust_session *usess;
+       const bool session_rotated_after_last_stop =
+                       session->rotated_after_last_stop;
+       const bool session_cleared_after_last_stop =
+                       session->cleared_after_last_stop;
 
        assert(session);
 
@@ -2558,6 +2586,23 @@ int cmd_start_trace(struct ltt_session *session)
        /* Is the session already started? */
        if (session->active) {
                ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+               /* Perform nothing */
+               goto end;
+       }
+
+       if (session->rotation_state == LTTNG_ROTATION_STATE_ONGOING &&
+                       !session->current_trace_chunk) {
+               /*
+                * A rotation was launched while the session was stopped and
+                * it has not been completed yet. It is not possible to start
+                * the session since starting the session here would require a
+                * rotation from "NULL" to a new trace chunk. That rotation
+                * would overlap with the ongoing rotation, which is not
+                * supported.
+                */
+               WARN("Refusing to start session \"%s\" as a rotation launched after the last \"stop\" is still ongoing",
+                               session->name);
+               ret = LTTNG_ERR_ROTATION_PENDING;
                goto error;
        }
 
@@ -2576,28 +2621,54 @@ int cmd_start_trace(struct ltt_session *session)
                goto error;
        }
 
+       session->active = 1;
+       session->rotated_after_last_stop = false;
+       session->cleared_after_last_stop = false;
        if (session->output_traces && !session->current_trace_chunk) {
-               struct lttng_trace_chunk *trace_chunk;
+               if (!session->has_been_started) {
+                       struct lttng_trace_chunk *trace_chunk;
 
-               trace_chunk = session_create_new_trace_chunk(
-                               session, NULL, NULL);
-               if (!trace_chunk) {
-                       ret = LTTNG_ERR_CREATE_DIR_FAIL;
-                       goto error;
-               }
-               assert(!session->current_trace_chunk);
-               ret = session_set_trace_chunk(session, trace_chunk, NULL);
-               lttng_trace_chunk_put(trace_chunk);
-               if (ret) {
-                       ret = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
-                       goto error;
+                       DBG("Creating initial trace chunk of session \"%s\"",
+                                       session->name);
+                       trace_chunk = session_create_new_trace_chunk(
+                                       session, NULL, NULL, NULL);
+                       if (!trace_chunk) {
+                               ret = LTTNG_ERR_CREATE_DIR_FAIL;
+                               goto error;
+                       }
+                       assert(!session->current_trace_chunk);
+                       ret = session_set_trace_chunk(session, trace_chunk,
+                                       NULL);
+                       lttng_trace_chunk_put(trace_chunk);
+                       if (ret) {
+                               ret = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
+                               goto error;
+                       }
+               } else {
+                       DBG("Rotating session \"%s\" from its current \"NULL\" trace chunk to a new chunk",
+                                       session->name);
+                       /*
+                        * Rotate existing streams into the new chunk.
+                        * This is a "quiet" rotation has no client has
+                        * explicitly requested this operation.
+                        *
+                        * There is also no need to wait for the rotation
+                        * to complete as it will happen immediately. No data
+                        * was produced as the session was stopped, so the
+                        * rotation should happen on reception of the command.
+                        */
+                       ret = cmd_rotate_session(session, NULL, true,
+                                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION);
+                       if (ret != LTTNG_OK) {
+                               goto error;
+                       }
                }
        }
 
        /* Kernel tracing */
        if (ksession != NULL) {
                DBG("Start kernel tracing session %s", session->name);
-               ret = start_kernel_session(ksession, kernel_tracer_fd);
+               ret = start_kernel_session(ksession);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -2613,9 +2684,15 @@ int cmd_start_trace(struct ltt_session *session)
                }
        }
 
-       /* Flag this after a successful start. */
-       session->has_been_started = 1;
-       session->active = 1;
+       /*
+        * Open a packet in every stream of the session to ensure that viewers
+        * can correctly identify the boundaries of the periods during which
+        * tracing was active for this session.
+        */
+       ret = session_open_packets(session);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
 
        /*
         * Clear the flag that indicates that a rotation was done while the
@@ -2637,6 +2714,18 @@ int cmd_start_trace(struct ltt_session *session)
        ret = LTTNG_OK;
 
 error:
+       if (ret == LTTNG_OK) {
+               /* Flag this after a successful start. */
+               session->has_been_started |= 1;
+       } else {
+               session->active = 0;
+               /* Restore initial state on error. */
+               session->rotated_after_last_stop =
+                               session_rotated_after_last_stop;
+               session->cleared_after_last_stop =
+                               session_cleared_after_last_stop;
+       }
+end:
        return ret;
 }
 
@@ -2646,55 +2735,25 @@ error:
 int cmd_stop_trace(struct ltt_session *session)
 {
        int ret;
-       struct ltt_kernel_channel *kchan;
        struct ltt_kernel_session *ksession;
        struct ltt_ust_session *usess;
-       bool error_occurred = false;
 
        assert(session);
 
-       DBG("Begin stop session %s (id %" PRIu64 ")", session->name, session->id);
+       DBG("Begin stop session \"%s\" (id %" PRIu64 ")", session->name, session->id);
        /* Short cut */
        ksession = session->kernel_session;
        usess = session->ust_session;
 
        /* Session is not active. Skip everythong and inform the client. */
        if (!session->active) {
-               ret = LTTNG_ERR_TRACE_ALREADY_STOPPED;
-               goto error;
-       }
-
-       /* Kernel tracer */
-       if (ksession && ksession->active) {
-               DBG("Stop kernel tracing");
-
-               ret = kernel_stop_session(ksession);
-               if (ret < 0) {
-                       ret = LTTNG_ERR_KERN_STOP_FAIL;
-                       goto error;
-               }
-
-               kernel_wait_quiescent(kernel_tracer_fd);
-
-               /* Flush metadata after stopping (if exists) */
-               if (ksession->metadata_stream_fd >= 0) {
-                       ret = kernel_metadata_flush_buffer(ksession->metadata_stream_fd);
-                       if (ret < 0) {
-                               ERR("Kernel metadata flush failed");
-                       }
-               }
-
-               /* Flush all buffers after stopping */
-               cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
-                       ret = kernel_flush_buffer(kchan);
-                       if (ret < 0) {
-                               ERR("Kernel flush buffer error");
-                       }
-               }
+               ret = LTTNG_ERR_TRACE_ALREADY_STOPPED;
+               goto error;
+       }
 
-               ksession->active = 0;
-               DBG("Kernel session stopped %s (id %" PRIu64 ")", session->name,
-                               session->id);
+       ret = stop_kernel_session(ksession);
+       if (ret != LTTNG_OK) {
+               goto error;
        }
 
        if (usess && usess->active) {
@@ -2705,10 +2764,51 @@ int cmd_stop_trace(struct ltt_session *session)
                }
        }
 
+       DBG("Completed stop session \"%s\" (id %" PRIu64 ")", session->name,
+                       session->id);
        /* Flag inactive after a successful stop. */
        session->active = 0;
-       ret = !error_occurred ? LTTNG_OK : LTTNG_ERR_UNK;
+       ret = LTTNG_OK;
+
+error:
+       return ret;
+}
+
+/*
+ * Set the base_path of the session only if subdir of a control uris is set.
+ * Return LTTNG_OK on success, otherwise LTTNG_ERR_*.
+ */
+static int set_session_base_path_from_uris(struct ltt_session *session,
+               size_t nb_uri,
+               struct lttng_uri *uris)
+{
+       int ret;
+       size_t i;
+
+       for (i = 0; i < nb_uri; i++) {
+               if (uris[i].stype != LTTNG_STREAM_CONTROL ||
+                               uris[i].subdir[0] == '\0') {
+                       /* Not interested in these URIs */
+                       continue;
+               }
+
+               if (session->base_path != NULL) {
+                       free(session->base_path);
+                       session->base_path = NULL;
+               }
 
+               /* Set session base_path */
+               session->base_path = strdup(uris[i].subdir);
+               if (!session->base_path) {
+                       PERROR("Failed to copy base path \"%s\" to session \"%s\"",
+                                       uris[i].subdir, session->name);
+                       ret = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+               DBG2("Setting base path \"%s\" for session \"%s\"",
+                               session->base_path, session->name);
+       }
+       ret = LTTNG_OK;
 error:
        return ret;
 }
@@ -2733,11 +2833,20 @@ int cmd_set_consumer_uri(struct ltt_session *session, size_t nb_uri,
                goto error;
        }
 
+       /*
+        * Set the session base path if any. This is done inside
+        * cmd_set_consumer_uri to preserve backward compatibility of the
+        * previous session creation api vs the session descriptor api.
+        */
+       ret = set_session_base_path_from_uris(session, nb_uri, uris);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
+
        /* Set the "global" consumer URIs */
        for (i = 0; i < nb_uri; i++) {
-               ret = add_uri_to_consumer(session,
-                               session->consumer,
-                               &uris[i], LTTNG_DOMAIN_NONE);
+               ret = add_uri_to_consumer(session, session->consumer, &uris[i],
+                               LTTNG_DOMAIN_NONE);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -2890,6 +2999,7 @@ enum lttng_error_code cmd_create_session_from_descriptor(
                ret_code = LTTNG_ERR_INVALID;
                goto end;
        }
+
        ret_code = session_create(session_name, creds->uid, creds->gid,
                        &new_session);
        if (ret_code != LTTNG_OK) {
@@ -2967,19 +3077,19 @@ enum lttng_error_code cmd_create_session(struct command_ctx *cmd_ctx, int sock,
        enum lttng_error_code ret_code;
 
        lttng_dynamic_buffer_init(&payload);
-       if (cmd_ctx->lsm->u.create_session.home_dir_size >=
+       if (cmd_ctx->lsm.u.create_session.home_dir_size >=
                        LTTNG_PATH_MAX) {
                ret_code = LTTNG_ERR_INVALID;
                goto error;
        }
-       if (cmd_ctx->lsm->u.create_session.session_descriptor_size >
+       if (cmd_ctx->lsm.u.create_session.session_descriptor_size >
                        LTTNG_SESSION_DESCRIPTOR_MAX_LEN) {
                ret_code = LTTNG_ERR_INVALID;
                goto error;
        }
 
-       payload_size = cmd_ctx->lsm->u.create_session.home_dir_size +
-                       cmd_ctx->lsm->u.create_session.session_descriptor_size;
+       payload_size = cmd_ctx->lsm.u.create_session.home_dir_size +
+                       cmd_ctx->lsm.u.create_session.session_descriptor_size;
        ret = lttng_dynamic_buffer_set_size(&payload, payload_size);
        if (ret) {
                ret_code = LTTNG_ERR_NOMEM;
@@ -2996,11 +3106,11 @@ enum lttng_error_code cmd_create_session(struct command_ctx *cmd_ctx, int sock,
        home_dir_view = lttng_buffer_view_from_dynamic_buffer(
                        &payload,
                        0,
-                       cmd_ctx->lsm->u.create_session.home_dir_size);
+                       cmd_ctx->lsm.u.create_session.home_dir_size);
        session_descriptor_view = lttng_buffer_view_from_dynamic_buffer(
                        &payload,
-                       cmd_ctx->lsm->u.create_session.home_dir_size,
-                       cmd_ctx->lsm->u.create_session.session_descriptor_size);
+                       cmd_ctx->lsm.u.create_session.home_dir_size,
+                       cmd_ctx->lsm.u.create_session.session_descriptor_size);
 
        ret = lttng_session_descriptor_create_from_buffer(
                        &session_descriptor_view, &session_descriptor);
@@ -3043,7 +3153,7 @@ void cmd_destroy_session_reply(const struct ltt_session *session,
        struct lttng_trace_archive_location *location = NULL;
        struct lttcomm_lttng_msg llm = {
                .cmd_type = LTTNG_DESTROY_SESSION,
-               .ret_code = LTTNG_OK,
+               .ret_code = reply_context->destruction_status,
                .pid = UINT32_MAX,
                .cmd_header_size =
                        sizeof(struct lttcomm_session_destroy_command_header),
@@ -3054,10 +3164,10 @@ void cmd_destroy_session_reply(const struct ltt_session *session,
        lttng_dynamic_buffer_init(&payload);
 
        ret = lttng_dynamic_buffer_append(&payload, &llm, sizeof(llm));
-        if (ret) {
+       if (ret) {
                ERR("Failed to append session destruction message");
                goto error;
-        }
+       }
 
        cmd_header.rotation_state =
                        (int32_t) (reply_context->implicit_rotation_on_destroy ?
@@ -3125,6 +3235,7 @@ int cmd_destroy_session(struct ltt_session *session,
                int *sock_fd)
 {
        int ret;
+       enum lttng_error_code destruction_last_error = LTTNG_OK;
        struct cmd_destroy_session_reply_context *reply_context = NULL;
 
        if (sock_fd) {
@@ -3149,6 +3260,7 @@ int cmd_destroy_session(struct ltt_session *session,
                        /* Carry on with the destruction of the session. */
                        ERR("Failed to stop session \"%s\" as part of its destruction: %s",
                                        session->name, lttng_strerror(-ret));
+                       destruction_last_error = ret;
                }
        }
 
@@ -3157,6 +3269,7 @@ int cmd_destroy_session(struct ltt_session *session,
                                session)) {
                        ERR("Failed to stop the \"rotation schedule\" timer of session %s",
                                        session->name);
+                       destruction_last_error = LTTNG_ERR_TIMER_STOP_ERROR;
                }
        }
 
@@ -3165,18 +3278,47 @@ int cmd_destroy_session(struct ltt_session *session,
                session->rotate_size = 0;
        }
 
-       if (session->most_recent_chunk_id.is_set &&
-                       session->most_recent_chunk_id.value != 0 &&
-                       session->current_trace_chunk) {
-               ret = cmd_rotate_session(session, NULL);
+       if (session->rotated && session->current_trace_chunk && session->output_traces) {
+               /*
+                * Perform a last rotation on destruction if rotations have
+                * occurred during the session's lifetime.
+                */
+               ret = cmd_rotate_session(session, NULL, false,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
                if (ret != LTTNG_OK) {
                        ERR("Failed to perform an implicit rotation as part of the destruction of session \"%s\": %s",
                                        session->name, lttng_strerror(-ret));
+                       destruction_last_error = -ret;
                }
-                if (reply_context) {
+               if (reply_context) {
                        reply_context->implicit_rotation_on_destroy = true;
-                }
-        }
+               }
+       } else if (session->has_been_started && session->current_trace_chunk) {
+               /*
+                * The user has not triggered a session rotation. However, to
+                * ensure all data has been consumed, the session is rotated
+                * to a 'null' trace chunk before it is destroyed.
+                *
+                * This is a "quiet" rotation meaning that no notification is
+                * emitted and no renaming of the current trace chunk takes
+                * place.
+                */
+               ret = cmd_rotate_session(session, NULL, true,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION);
+               /*
+                * Rotation operations may not be supported by the kernel
+                * tracer. Hence, do not consider this implicit rotation as
+                * a session destruction error. The library has already stopped
+                * the session and waited for pending data; there is nothing
+                * left to do but complete the destruction of the session.
+                */
+               if (ret != LTTNG_OK &&
+                               ret != -LTTNG_ERR_ROTATION_NOT_AVAILABLE_KERNEL) {
+                       ERR("Failed to perform a quiet rotation as part of the destruction of session \"%s\": %s",
+                           session->name, lttng_strerror(ret));
+                       destruction_last_error = -ret;
+               }
+       }
 
        if (session->shm_path[0]) {
                /*
@@ -3239,6 +3381,7 @@ int cmd_destroy_session(struct ltt_session *session,
         */
        session_destroy(session);
        if (reply_context) {
+               reply_context->destruction_status = destruction_last_error;
                ret = session_add_destroy_notifier(session,
                                cmd_destroy_session_reply,
                                (void *) reply_context);
@@ -3248,8 +3391,8 @@ int cmd_destroy_session(struct ltt_session *session,
                } else {
                        *sock_fd = -1;
                }
-        }
-        ret = LTTNG_OK;
+       }
+       ret = LTTNG_OK;
 end:
        return ret;
 }
@@ -3478,25 +3621,33 @@ end:
  */
 ssize_t cmd_list_events(enum lttng_domain_type domain,
                struct ltt_session *session, char *channel_name,
-               struct lttng_event **events, size_t *total_size)
+               struct lttng_payload *payload)
 {
        int ret = 0;
-       ssize_t nb_event = 0;
+       ssize_t nb_events = 0;
+       struct lttcomm_event_command_header cmd_header = {};
+       const size_t cmd_header_offset = payload->buffer.size;
+
+       ret = lttng_dynamic_buffer_append(
+                       &payload->buffer, &cmd_header, sizeof(cmd_header));
+       if (ret) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
 
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
                if (session->kernel_session != NULL) {
-                       nb_event = list_lttng_kernel_events(channel_name,
-                                       session->kernel_session, events,
-                                       total_size);
+                       nb_events = list_lttng_kernel_events(channel_name,
+                                       session->kernel_session, payload);
                }
                break;
        case LTTNG_DOMAIN_UST:
        {
                if (session->ust_session != NULL) {
-                       nb_event = list_lttng_ust_global_events(channel_name,
-                                       &session->ust_session->domain_global, events,
-                                       total_size);
+                       nb_events = list_lttng_ust_global_events(channel_name,
+                                       &session->ust_session->domain_global,
+                                       payload);
                }
                break;
        }
@@ -3511,9 +3662,8 @@ ssize_t cmd_list_events(enum lttng_domain_type domain,
                        cds_lfht_for_each_entry(session->ust_session->agents->ht,
                                        &iter.iter, agt, node.node) {
                                if (agt->domain == domain) {
-                                       nb_event = list_lttng_agent_events(
-                                                       agt, events,
-                                                       total_size);
+                                       nb_events = list_lttng_agent_events(
+                                                       agt, payload);
                                        break;
                                }
                        }
@@ -3525,7 +3675,10 @@ ssize_t cmd_list_events(enum lttng_domain_type domain,
                goto error;
        }
 
-       return nb_event;
+       ((struct lttcomm_event_command_header *) (payload->buffer.data +
+                        cmd_header_offset))->nb_events = (uint32_t) nb_events;
+
+       return nb_events;
 
 error:
        /* Return negative value to differentiate return code */
@@ -3546,7 +3699,7 @@ void cmd_list_lttng_sessions(struct lttng_session *sessions,
        unsigned int i = 0;
        struct ltt_session *session;
        struct ltt_session_list *list = session_get_list();
-        struct lttng_session_extended *extended =
+       struct lttng_session_extended *extended =
                        (typeof(extended)) (&sessions[session_count]);
 
        DBG("Getting all available session for UID %d GID %d",
@@ -3669,7 +3822,7 @@ error:
  * Return LTTNG_OK on success or else a LTTNG_ERR code.
  */
 int cmd_snapshot_add_output(struct ltt_session *session,
-               struct lttng_snapshot_output *output, uint32_t *id)
+               const struct lttng_snapshot_output *output, uint32_t *id)
 {
        int ret;
        struct snapshot_output *new_output;
@@ -3737,7 +3890,7 @@ error:
  * Return LTTNG_OK on success or else a LTTNG_ERR code.
  */
 int cmd_snapshot_del_output(struct ltt_session *session,
-               struct lttng_snapshot_output *output)
+               const struct lttng_snapshot_output *output)
 {
        int ret;
        struct snapshot_output *sout = NULL;
@@ -4110,19 +4263,23 @@ int cmd_register_trigger(struct command_ctx *cmd_ctx, int sock,
        size_t trigger_len;
        ssize_t sock_recv_len;
        struct lttng_trigger *trigger = NULL;
-       struct lttng_buffer_view view;
-       struct lttng_dynamic_buffer trigger_buffer;
+       struct lttng_payload trigger_payload;
+       struct lttng_credentials cmd_creds = {
+               .uid = cmd_ctx->creds.uid,
+               .gid = cmd_ctx->creds.gid,
+       };
 
-       lttng_dynamic_buffer_init(&trigger_buffer);
-       trigger_len = (size_t) cmd_ctx->lsm->u.trigger.length;
-       ret = lttng_dynamic_buffer_set_size(&trigger_buffer, trigger_len);
+       lttng_payload_init(&trigger_payload);
+       trigger_len = (size_t) cmd_ctx->lsm.u.trigger.length;
+       ret = lttng_dynamic_buffer_set_size(
+                       &trigger_payload.buffer, trigger_len);
        if (ret) {
                ret = LTTNG_ERR_NOMEM;
                goto end;
        }
 
-       sock_recv_len = lttcomm_recv_unix_sock(sock, trigger_buffer.data,
-                       trigger_len);
+       sock_recv_len = lttcomm_recv_unix_sock(
+                       sock, trigger_payload.buffer.data, trigger_len);
        if (sock_recv_len < 0 || sock_recv_len != trigger_len) {
                ERR("Failed to receive \"register trigger\" command payload");
                /* TODO: should this be a new error enum ? */
@@ -4130,21 +4287,44 @@ int cmd_register_trigger(struct command_ctx *cmd_ctx, int sock,
                goto end;
        }
 
-       view = lttng_buffer_view_from_dynamic_buffer(&trigger_buffer, 0, -1);
-       if (lttng_trigger_create_from_buffer(&view, &trigger) !=
-                       trigger_len) {
-               ERR("Invalid trigger payload received in \"register trigger\" command");
-               ret = LTTNG_ERR_INVALID_TRIGGER;
-               goto end;
+       /* Receive fds, if any. */
+       if (cmd_ctx->lsm.fd_count > 0) {
+               ret = lttcomm_recv_payload_fds_unix_sock(
+                               sock, cmd_ctx->lsm.fd_count, &trigger_payload);
+               if (ret > 0 && ret != cmd_ctx->lsm.fd_count * sizeof(int)) {
+                       ret = LTTNG_ERR_INVALID_PROTOCOL;
+                       goto end;
+               } else if (ret <= 0) {
+                       ret = LTTNG_ERR_FATAL;
+                       goto end;
+               }
+       }
+
+       /* Deserialize trigger. */
+       {
+               struct lttng_payload_view view =
+                               lttng_payload_view_from_payload(
+                                               &trigger_payload, 0, -1);
+
+               if (lttng_trigger_create_from_payload(&view, &trigger) !=
+                               trigger_len) {
+                       ERR("Invalid trigger payload received in \"register trigger\" command");
+                       ret = LTTNG_ERR_INVALID_TRIGGER;
+                       goto end;
+               }
        }
 
+       /* Set the trigger credential */
+       lttng_trigger_set_credentials(trigger, &cmd_creds);
+
+       /* Inform the notification thread */
        ret = notification_thread_command_register_trigger(notification_thread,
                        trigger);
        /* Ownership of trigger was transferred. */
        trigger = NULL;
 end:
        lttng_trigger_destroy(trigger);
-       lttng_dynamic_buffer_reset(&trigger_buffer);
+       lttng_payload_reset(&trigger_payload);
        return ret;
 }
 
@@ -4155,19 +4335,23 @@ int cmd_unregister_trigger(struct command_ctx *cmd_ctx, int sock,
        size_t trigger_len;
        ssize_t sock_recv_len;
        struct lttng_trigger *trigger = NULL;
-       struct lttng_buffer_view view;
-       struct lttng_dynamic_buffer trigger_buffer;
+       struct lttng_payload trigger_payload;
+       struct lttng_credentials cmd_creds = {
+               .uid = cmd_ctx->creds.uid,
+               .gid = cmd_ctx->creds.gid,
+       };
 
-       lttng_dynamic_buffer_init(&trigger_buffer);
-       trigger_len = (size_t) cmd_ctx->lsm->u.trigger.length;
-       ret = lttng_dynamic_buffer_set_size(&trigger_buffer, trigger_len);
+       lttng_payload_init(&trigger_payload);
+       trigger_len = (size_t) cmd_ctx->lsm.u.trigger.length;
+       ret = lttng_dynamic_buffer_set_size(
+                       &trigger_payload.buffer, trigger_len);
        if (ret) {
                ret = LTTNG_ERR_NOMEM;
                goto end;
        }
 
-       sock_recv_len = lttcomm_recv_unix_sock(sock, trigger_buffer.data,
-                       trigger_len);
+       sock_recv_len = lttcomm_recv_unix_sock(
+                       sock, trigger_payload.buffer.data, trigger_len);
        if (sock_recv_len < 0 || sock_recv_len != trigger_len) {
                ERR("Failed to receive \"unregister trigger\" command payload");
                /* TODO: should this be a new error enum ? */
@@ -4175,19 +4359,39 @@ int cmd_unregister_trigger(struct command_ctx *cmd_ctx, int sock,
                goto end;
        }
 
-       view = lttng_buffer_view_from_dynamic_buffer(&trigger_buffer, 0, -1);
-       if (lttng_trigger_create_from_buffer(&view, &trigger) !=
-                       trigger_len) {
-               ERR("Invalid trigger payload received in \"unregister trigger\" command");
-               ret = LTTNG_ERR_INVALID_TRIGGER;
-               goto end;
+       /* Receive fds, if any. */
+       if (cmd_ctx->lsm.fd_count > 0) {
+               ret = lttcomm_recv_payload_fds_unix_sock(
+                               sock, cmd_ctx->lsm.fd_count, &trigger_payload);
+               if (ret > 0 && ret != cmd_ctx->lsm.fd_count * sizeof(int)) {
+                       ret = LTTNG_ERR_INVALID_PROTOCOL;
+                       goto end;
+               } else if (ret <= 0) {
+                       ret = LTTNG_ERR_FATAL;
+                       goto end;
+               }
+       }
+
+       {
+               struct lttng_payload_view view =
+                               lttng_payload_view_from_payload(
+                                               &trigger_payload, 0, -1);
+
+               if (lttng_trigger_create_from_payload(&view, &trigger) !=
+                               trigger_len) {
+                       ERR("Invalid trigger payload received in \"unregister trigger\" command");
+                       ret = LTTNG_ERR_INVALID_TRIGGER;
+                       goto end;
+               }
        }
 
+       lttng_trigger_set_credentials(trigger, &cmd_creds);
+
        ret = notification_thread_command_unregister_trigger(notification_thread,
                        trigger);
 end:
        lttng_trigger_destroy(trigger);
-       lttng_dynamic_buffer_reset(&trigger_buffer);
+       lttng_payload_reset(&trigger_payload);
        return ret;
 }
 
@@ -4198,26 +4402,27 @@ end:
  * Return LTTNG_OK on success or a LTTNG_ERR code.
  */
 static enum lttng_error_code set_relayd_for_snapshot(
-               struct consumer_output *consumer,
-               const struct snapshot_output *snap_output,
+               struct consumer_output *output,
                const struct ltt_session *session)
 {
        enum lttng_error_code status = LTTNG_OK;
        struct lttng_ht_iter iter;
        struct consumer_socket *socket;
        LTTNG_OPTIONAL(uint64_t) current_chunk_id = {};
+       const char *base_path;
 
-       assert(consumer);
-       assert(snap_output);
+       assert(output);
        assert(session);
 
        DBG2("Set relayd object from snapshot output");
 
        if (session->current_trace_chunk) {
-               enum lttng_trace_chunk_status status = lttng_trace_chunk_get_id(
-                               session->current_trace_chunk, &current_chunk_id.value);
+               enum lttng_trace_chunk_status chunk_status =
+                               lttng_trace_chunk_get_id(
+                                               session->current_trace_chunk,
+                                               &current_chunk_id.value);
 
-               if (status == LTTNG_TRACE_CHUNK_STATUS_OK) {
+               if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK) {
                        current_chunk_id.is_set = true;
                } else {
                        ERR("Failed to get current trace chunk id");
@@ -4227,23 +4432,36 @@ static enum lttng_error_code set_relayd_for_snapshot(
        }
 
        /* Ignore if snapshot consumer output is not network. */
-       if (snap_output->consumer->type != CONSUMER_DST_NET) {
+       if (output->type != CONSUMER_DST_NET) {
                goto error;
        }
 
+       /*
+        * The snapshot record URI base path overrides the session
+        * base path.
+        */
+       if (output->dst.net.control.subdir[0] != '\0') {
+               base_path = output->dst.net.control.subdir;
+       } else {
+               base_path = session->base_path;
+       }
+
        /*
         * For each consumer socket, create and send the relayd object of the
         * snapshot output.
         */
        rcu_read_lock();
-       cds_lfht_for_each_entry(snap_output->consumer->socks->ht, &iter.iter,
+       cds_lfht_for_each_entry(output->socks->ht, &iter.iter,
                        socket, node.node) {
                pthread_mutex_lock(socket->lock);
                status = send_consumer_relayd_sockets(0, session->id,
-                               snap_output->consumer, socket,
+                               output, socket,
                                session->name, session->hostname,
+                               base_path,
                                session->live_timer,
-                               current_chunk_id.is_set ? &current_chunk_id.value : NULL);
+                               current_chunk_id.is_set ? &current_chunk_id.value : NULL,
+                               session->creation_time,
+                               session->name_contains_creation_time);
                pthread_mutex_unlock(socket->lock);
                if (status != LTTNG_OK) {
                        rcu_read_unlock();
@@ -4263,44 +4481,18 @@ error:
  */
 static enum lttng_error_code record_kernel_snapshot(
                struct ltt_kernel_session *ksess,
-               const struct snapshot_output *output,
+               const struct consumer_output *output,
                const struct ltt_session *session,
                int wait, uint64_t nb_packets_per_stream)
 {
-       int ret;
        enum lttng_error_code status;
 
        assert(ksess);
        assert(output);
        assert(session);
 
-       /*
-        * Copy kernel session sockets so we can communicate with the right
-        * consumer for the snapshot record command.
-        */
-       ret = consumer_copy_sockets(output->consumer, ksess->consumer);
-       if (ret < 0) {
-               status = LTTNG_ERR_NOMEM;
-               goto error;
-       }
-
-       status = set_relayd_for_snapshot(ksess->consumer, output, session);
-       if (status != LTTNG_OK) {
-               goto error_snapshot;
-       }
-
-       status = kernel_snapshot_record(ksess, output, wait, nb_packets_per_stream);
-       if (status != LTTNG_OK) {
-               goto error_snapshot;
-       }
-
-       goto end;
-
-error_snapshot:
-       /* Clean up copied sockets so this output can use some other later on. */
-       consumer_destroy_output_sockets(output->consumer);
-error:
-end:
+       status = kernel_snapshot_record(
+                       ksess, output, wait, nb_packets_per_stream);
        return status;
 }
 
@@ -4310,45 +4502,18 @@ end:
  * Returns LTTNG_OK on success or a LTTNG_ERR error code.
  */
 static enum lttng_error_code record_ust_snapshot(struct ltt_ust_session *usess,
-               const struct snapshot_output *output,
-               const struct ltt_session *session, int wait,
-               uint64_t nb_packets_per_stream)
+               const struct consumer_output *output,
+               const struct ltt_session *session,
+               int wait, uint64_t nb_packets_per_stream)
 {
-       int ret;
        enum lttng_error_code status;
 
        assert(usess);
        assert(output);
        assert(session);
 
-       /*
-        * Copy UST session sockets so we can communicate with the right
-        * consumer for the snapshot record command.
-        */
-       ret = consumer_copy_sockets(output->consumer, usess->consumer);
-       if (ret < 0) {
-               status = LTTNG_ERR_NOMEM;
-               goto error;
-       }
-
-       status = set_relayd_for_snapshot(usess->consumer, output, session);
-       if (status != LTTNG_OK) {
-               goto error_snapshot;
-       }
-
-       status = ust_app_snapshot_record(usess, output, wait,
-                       nb_packets_per_stream);
-       if (status != LTTNG_OK) {
-               goto error_snapshot;
-       }
-
-       goto end;
-
-error_snapshot:
-       /* Clean up copied sockets so this output can use some other later on. */
-       consumer_destroy_output_sockets(output->consumer);
-error:
-end:
+       status = ust_app_snapshot_record(
+                       usess, output, wait, nb_packets_per_stream);
        return status;
 }
 
@@ -4433,7 +4598,7 @@ int64_t get_session_nb_packets_per_stream(const struct ltt_session *session,
                }
                cur_nb_packets++;
        }
-       if (!cur_nb_packets) {
+       if (!cur_nb_packets && size_left != max_size) {
                /* Not enough room to grab one packet of each stream, error. */
                return -1;
        }
@@ -4444,83 +4609,157 @@ static
 enum lttng_error_code snapshot_record(struct ltt_session *session,
                const struct snapshot_output *snapshot_output, int wait)
 {
-       int fmt_ret;
        int64_t nb_packets_per_stream;
        char snapshot_chunk_name[LTTNG_NAME_MAX];
-       enum lttng_error_code ret = LTTNG_OK;
+       int ret;
+       enum lttng_error_code ret_code = LTTNG_OK;
        struct lttng_trace_chunk *snapshot_trace_chunk;
+       struct consumer_output *original_ust_consumer_output = NULL;
+       struct consumer_output *original_kernel_consumer_output = NULL;
+       struct consumer_output *snapshot_ust_consumer_output = NULL;
+       struct consumer_output *snapshot_kernel_consumer_output = NULL;
 
-       fmt_ret = snprintf(snapshot_chunk_name, sizeof(snapshot_chunk_name),
+       ret = snprintf(snapshot_chunk_name, sizeof(snapshot_chunk_name),
                        "%s-%s-%" PRIu64,
                        snapshot_output->name,
                        snapshot_output->datetime,
                        snapshot_output->nb_snapshot);
-       if (fmt_ret < 0 || fmt_ret >= sizeof(snapshot_chunk_name)) {
+       if (ret < 0 || ret >= sizeof(snapshot_chunk_name)) {
                ERR("Failed to format snapshot name");
-               ret = LTTNG_ERR_INVALID;
-               goto end;
+               ret_code = LTTNG_ERR_INVALID;
+               goto error;
        }
        DBG("Recording snapshot \"%s\" for session \"%s\" with chunk name \"%s\"",
                        snapshot_output->name, session->name,
                        snapshot_chunk_name);
+       if (!session->kernel_session && !session->ust_session) {
+               ERR("Failed to record snapshot as no channels exist");
+               ret_code = LTTNG_ERR_NO_CHANNEL;
+               goto error;
+       }
+
+       if (session->kernel_session) {
+               original_kernel_consumer_output =
+                               session->kernel_session->consumer;
+               snapshot_kernel_consumer_output =
+                               consumer_copy_output(snapshot_output->consumer);
+               strcpy(snapshot_kernel_consumer_output->chunk_path,
+                       snapshot_chunk_name);
+               ret = consumer_copy_sockets(snapshot_kernel_consumer_output,
+                               original_kernel_consumer_output);
+               if (ret < 0) {
+                       ERR("Failed to copy consumer sockets from snapshot output configuration");
+                       ret_code = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+               ret_code = set_relayd_for_snapshot(
+                               snapshot_kernel_consumer_output, session);
+               if (ret_code != LTTNG_OK) {
+                       ERR("Failed to setup relay daemon for kernel tracer snapshot");
+                       goto error;
+               }
+               session->kernel_session->consumer =
+                               snapshot_kernel_consumer_output;
+       }
+       if (session->ust_session) {
+               original_ust_consumer_output = session->ust_session->consumer;
+               snapshot_ust_consumer_output =
+                               consumer_copy_output(snapshot_output->consumer);
+               strcpy(snapshot_ust_consumer_output->chunk_path,
+                       snapshot_chunk_name);
+               ret = consumer_copy_sockets(snapshot_ust_consumer_output,
+                               original_ust_consumer_output);
+               if (ret < 0) {
+                       ERR("Failed to copy consumer sockets from snapshot output configuration");
+                       ret_code = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+               ret_code = set_relayd_for_snapshot(
+                               snapshot_ust_consumer_output, session);
+               if (ret_code != LTTNG_OK) {
+                       ERR("Failed to setup relay daemon for userspace tracer snapshot");
+                       goto error;
+               }
+               session->ust_session->consumer =
+                               snapshot_ust_consumer_output;
+       }
+
        snapshot_trace_chunk = session_create_new_trace_chunk(session,
-                       snapshot_output_get_base_path(snapshot_output),
+                       snapshot_kernel_consumer_output ?:
+                                       snapshot_ust_consumer_output,
+                       consumer_output_get_base_path(
+                                       snapshot_output->consumer),
                        snapshot_chunk_name);
        if (!snapshot_trace_chunk) {
-               ret = LTTNG_ERR_CREATE_DIR_FAIL;
-               goto end;
+               ERR("Failed to create temporary trace chunk to record a snapshot of session \"%s\"",
+                               session->name);
+               ret_code = LTTNG_ERR_CREATE_DIR_FAIL;
+               goto error;
        }
        assert(!session->current_trace_chunk);
        ret = session_set_trace_chunk(session, snapshot_trace_chunk, NULL);
        lttng_trace_chunk_put(snapshot_trace_chunk);
        snapshot_trace_chunk = NULL;
        if (ret) {
-               ret = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
-               goto end;
+               ERR("Failed to set temporary trace chunk to record a snapshot of session \"%s\"",
+                               session->name);
+               ret_code = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
+               goto error;
        }
 
        nb_packets_per_stream = get_session_nb_packets_per_stream(session,
                        snapshot_output->max_size);
        if (nb_packets_per_stream < 0) {
-               ret = LTTNG_ERR_MAX_SIZE_INVALID;
-               goto end;
+               ret_code = LTTNG_ERR_MAX_SIZE_INVALID;
+               goto error_close_trace_chunk;
        }
 
        if (session->kernel_session) {
-               ret = record_kernel_snapshot(session->kernel_session,
-                               snapshot_output, session,
+               ret_code = record_kernel_snapshot(session->kernel_session,
+                               snapshot_kernel_consumer_output, session,
                                wait, nb_packets_per_stream);
-               if (ret != LTTNG_OK) {
-                       goto end;
+               if (ret_code != LTTNG_OK) {
+                       goto error_close_trace_chunk;
                }
        }
 
        if (session->ust_session) {
-               ret = record_ust_snapshot(session->ust_session,
-                               snapshot_output, session,
+               ret_code = record_ust_snapshot(session->ust_session,
+                               snapshot_ust_consumer_output, session,
                                wait, nb_packets_per_stream);
-               if (ret != LTTNG_OK) {
-                       goto end;
+               if (ret_code != LTTNG_OK) {
+                       goto error_close_trace_chunk;
                }
        }
 
-       if (session_close_trace_chunk(
-                           session, session->current_trace_chunk, NULL)) {
+error_close_trace_chunk:
+       if (session_set_trace_chunk(session, NULL, &snapshot_trace_chunk)) {
+               ERR("Failed to release the current trace chunk of session \"%s\"",
+                               session->name);
+               ret_code = LTTNG_ERR_UNK;
+       }
+
+       if (session_close_trace_chunk(session, snapshot_trace_chunk,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION, NULL)) {
                /*
                 * Don't goto end; make sure the chunk is closed for the session
                 * to allow future snapshots.
                 */
                ERR("Failed to close snapshot trace chunk of session \"%s\"",
                                session->name);
-               ret = -1;
+               ret_code = LTTNG_ERR_CLOSE_TRACE_CHUNK_FAIL_CONSUMER;
        }
-       if (session_set_trace_chunk(session, NULL, NULL)) {
-               ERR("Failed to release the current trace chunk of session \"%s\"",
-                               session->name);
-               ret = -1;
+error:
+       if (original_ust_consumer_output) {
+               session->ust_session->consumer = original_ust_consumer_output;
        }
-end:
-       return ret;
+       if (original_kernel_consumer_output) {
+               session->kernel_session->consumer =
+                               original_kernel_consumer_output;
+       }
+       consumer_output_put(snapshot_ust_consumer_output);
+       consumer_output_put(snapshot_kernel_consumer_output);
+       return ret_code;
 }
 
 /*
@@ -4532,14 +4771,13 @@ end:
  * Return LTTNG_OK on success or else a LTTNG_ERR code.
  */
 int cmd_snapshot_record(struct ltt_session *session,
-               struct lttng_snapshot_output *output, int wait)
+               const struct lttng_snapshot_output *output, int wait)
 {
        enum lttng_error_code cmd_ret = LTTNG_OK;
        int ret;
-       unsigned int use_tmp_output = 0;
-       struct snapshot_output tmp_output;
        unsigned int snapshot_success = 0;
        char datetime[16];
+       struct snapshot_output *tmp_output = NULL;
 
        assert(session);
        assert(output);
@@ -4571,11 +4809,17 @@ int cmd_snapshot_record(struct ltt_session *session,
 
        /* Use temporary output for the session. */
        if (*output->ctrl_url != '\0') {
+               tmp_output = snapshot_output_alloc();
+               if (!tmp_output) {
+                       cmd_ret = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+
                ret = snapshot_output_init(session, output->max_size,
                                output->name,
                                output->ctrl_url, output->data_url,
                                session->consumer,
-                               &tmp_output, NULL);
+                               tmp_output, NULL);
                if (ret < 0) {
                        if (ret == -ENOMEM) {
                                cmd_ret = LTTNG_ERR_NOMEM;
@@ -4585,15 +4829,11 @@ int cmd_snapshot_record(struct ltt_session *session,
                        goto error;
                }
                /* Use the global session count for the temporary snapshot. */
-               tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+               tmp_output->nb_snapshot = session->snapshot.nb_snapshot;
 
                /* Use the global datetime */
-               memcpy(tmp_output.datetime, datetime, sizeof(datetime));
-               use_tmp_output = 1;
-       }
-
-       if (use_tmp_output) {
-               cmd_ret = snapshot_record(session, &tmp_output, wait);
+               memcpy(tmp_output->datetime, datetime, sizeof(datetime));
+               cmd_ret = snapshot_record(session, tmp_output, wait);
                if (cmd_ret != LTTNG_OK) {
                        goto error;
                }
@@ -4605,30 +4845,35 @@ int cmd_snapshot_record(struct ltt_session *session,
                rcu_read_lock();
                cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
                                &iter.iter, sout, node.node) {
+                       struct snapshot_output output_copy;
+
                        /*
-                        * Make a local copy of the output and assign the
-                        * possible temporary value given by the caller.
+                        * Make a local copy of the output and override output
+                        * parameters with those provided as part of the
+                        * command.
                         */
-                       memcpy(&tmp_output, sout, sizeof(tmp_output));
+                       memcpy(&output_copy, sout, sizeof(output_copy));
 
                        if (output->max_size != (uint64_t) -1ULL) {
-                               tmp_output.max_size = output->max_size;
+                               output_copy.max_size = output->max_size;
                        }
 
-                       tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
-                       memcpy(tmp_output.datetime, datetime, sizeof(datetime));
+                       output_copy.nb_snapshot = session->snapshot.nb_snapshot;
+                       memcpy(output_copy.datetime, datetime,
+                                       sizeof(datetime));
 
                        /* Use temporary name. */
                        if (*output->name != '\0') {
-                               if (lttng_strncpy(tmp_output.name, output->name,
-                                               sizeof(tmp_output.name))) {
+                               if (lttng_strncpy(output_copy.name,
+                                               output->name,
+                                               sizeof(output_copy.name))) {
                                        cmd_ret = LTTNG_ERR_INVALID;
                                        rcu_read_unlock();
                                        goto error;
                                }
                        }
 
-                       cmd_ret = snapshot_record(session, &tmp_output, wait);
+                       cmd_ret = snapshot_record(session, &output_copy, wait);
                        if (cmd_ret != LTTNG_OK) {
                                rcu_read_unlock();
                                goto error;
@@ -4645,6 +4890,9 @@ int cmd_snapshot_record(struct ltt_session *session,
        }
 
 error:
+       if (tmp_output) {
+               snapshot_output_destroy(tmp_output);
+       }
        return cmd_ret;
 }
 
@@ -4680,7 +4928,9 @@ int cmd_set_session_shm_path(struct ltt_session *session,
  * Returns LTTNG_OK on success or else a negative LTTng error code.
  */
 int cmd_rotate_session(struct ltt_session *session,
-               struct lttng_rotate_session_return *rotate_return)
+               struct lttng_rotate_session_return *rotate_return,
+               bool quiet_rotation,
+               enum lttng_trace_chunk_command_type command)
 {
        int ret;
        uint64_t ongoing_rotation_chunk_id;
@@ -4688,6 +4938,8 @@ int cmd_rotate_session(struct ltt_session *session,
        struct lttng_trace_chunk *chunk_being_archived = NULL;
        struct lttng_trace_chunk *new_trace_chunk = NULL;
        enum lttng_trace_chunk_status chunk_status;
+       bool failed_to_rotate = false;
+       enum lttng_error_code rotation_fail_code = LTTNG_OK;
 
        assert(session);
 
@@ -4696,19 +4948,32 @@ int cmd_rotate_session(struct ltt_session *session,
                goto end;
        }
 
-       if (session->live_timer || !session->output_traces) {
+       /*
+        * Explicit rotation is not supported for live sessions.
+        * However, live sessions can perform a quiet rotation on
+        * destroy.
+        * Rotation is not supported for snapshot traces (no output).
+        */
+       if ((!quiet_rotation && session->live_timer) ||
+                       !session->output_traces) {
                cmd_ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE;
                goto end;
        }
 
        /* Unsupported feature in lttng-relayd before 2.11. */
-       if (session->consumer->type == CONSUMER_DST_NET &&
+       if (!quiet_rotation && session->consumer->type == CONSUMER_DST_NET &&
                        (session->consumer->relay_major_version == 2 &&
                        session->consumer->relay_minor_version < 11)) {
                cmd_ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE_RELAY;
                goto end;
        }
 
+       /* Unsupported feature in lttng-modules before 2.8 (lack of sequence number). */
+       if (session->kernel_session && !kernel_supports_ring_buffer_packet_sequence_number()) {
+               cmd_ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE_KERNEL;
+               goto end;
+       }
+
        if (session->rotation_state == LTTNG_ROTATION_STATE_ONGOING) {
                DBG("Refusing to launch a rotation; a rotation is already in progress for session %s",
                                session->name);
@@ -4727,18 +4992,33 @@ int cmd_rotate_session(struct ltt_session *session,
                goto end;
        }
 
-       session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+       /*
+        * After a stop followed by a clear, disallow following rotations a they would
+        * generate empty chunks.
+        */
+       if (session->cleared_after_last_stop) {
+               DBG("Session \"%s\" was already cleared after stop, refusing rotation",
+                               session->name);
+               cmd_ret = LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR;
+               goto end;
+       }
 
        if (session->active) {
-               new_trace_chunk = session_create_new_trace_chunk(session,
+               new_trace_chunk = session_create_new_trace_chunk(session, NULL,
                                NULL, NULL);
                if (!new_trace_chunk) {
                        cmd_ret = LTTNG_ERR_CREATE_DIR_FAIL;
                        goto error;
                }
-        }
+       }
 
-        /* The current trace chunk becomes the chunk being archived. */
+       /*
+        * The current trace chunk becomes the chunk being archived.
+        *
+        * After this point, "chunk_being_archived" must absolutely
+        * be closed on the consumer(s), otherwise it will never be
+        * cleaned-up, which will result in a leak.
+        */
        ret = session_set_trace_chunk(session, new_trace_chunk,
                        &chunk_being_archived);
        if (ret) {
@@ -4746,32 +5026,54 @@ int cmd_rotate_session(struct ltt_session *session,
                goto error;
        }
 
-       assert(chunk_being_archived);
-       chunk_status = lttng_trace_chunk_get_id(chunk_being_archived,
-                       &ongoing_rotation_chunk_id);
-       assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
-
        if (session->kernel_session) {
                cmd_ret = kernel_rotate_session(session);
                if (cmd_ret != LTTNG_OK) {
-                       goto error;
+                       failed_to_rotate = true;
+                       rotation_fail_code = cmd_ret;
                }
        }
        if (session->ust_session) {
                cmd_ret = ust_app_rotate_session(session);
                if (cmd_ret != LTTNG_OK) {
+                       failed_to_rotate = true;
+                       rotation_fail_code = cmd_ret;
+               }
+       }
+
+       if (!session->active) {
+               session->rotated_after_last_stop = true;
+       }
+
+       if (!chunk_being_archived) {
+               DBG("Rotating session \"%s\" from a \"NULL\" trace chunk to a new trace chunk, skipping completion check",
+                               session->name);
+               if (failed_to_rotate) {
+                       cmd_ret = rotation_fail_code;
                        goto error;
                }
+               cmd_ret = LTTNG_OK;
+               goto end;
        }
 
+       session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+       chunk_status = lttng_trace_chunk_get_id(chunk_being_archived,
+                       &ongoing_rotation_chunk_id);
+       assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
+
        ret = session_close_trace_chunk(session, chunk_being_archived,
-                       &((enum lttng_trace_chunk_command_type) {
-                                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED}));
+               command, session->last_chunk_path);
        if (ret) {
                cmd_ret = LTTNG_ERR_CLOSE_TRACE_CHUNK_FAIL_CONSUMER;
                goto error;
        }
 
+       if (failed_to_rotate) {
+               cmd_ret = rotation_fail_code;
+               goto error;
+       }
+
+       session->quiet_rotation = quiet_rotation;
        ret = timer_session_rotation_pending_check_start(session,
                        DEFAULT_ROTATE_PENDING_TIMER);
        if (ret) {
@@ -4779,24 +5081,22 @@ int cmd_rotate_session(struct ltt_session *session,
                goto error;
        }
 
-       if (!session->active) {
-               session->rotated_after_last_stop = true;
-       }
-
        if (rotate_return) {
                rotate_return->rotation_id = ongoing_rotation_chunk_id;
        }
 
        session->chunk_being_archived = chunk_being_archived;
        chunk_being_archived = NULL;
-       ret = notification_thread_command_session_rotation_ongoing(
-                       notification_thread_handle,
-                       session->name, session->uid, session->gid,
-                       ongoing_rotation_chunk_id);
-       if (ret != LTTNG_OK) {
-               ERR("Failed to notify notification thread that a session rotation is ongoing for session %s",
-                               session->name);
-               cmd_ret = ret;
+       if (!quiet_rotation) {
+               ret = notification_thread_command_session_rotation_ongoing(
+                               notification_thread_handle,
+                               session->name, session->uid, session->gid,
+                               ongoing_rotation_chunk_id);
+               if (ret != LTTNG_OK) {
+                       ERR("Failed to notify notification thread that a session rotation is ongoing for session %s",
+                                       session->name);
+                       cmd_ret = ret;
+               }
        }
 
        DBG("Cmd rotate session %s, archive_id %" PRIu64 " sent",
@@ -4855,7 +5155,7 @@ int cmd_rotate_get_info(struct ltt_session *session,
 
        switch (rotation_state) {
        case LTTNG_ROTATION_STATE_NO_ROTATION:
-               DBG("Reporting that no rotation has occured within the lifetime of session \"%s\"",
+               DBG("Reporting that no rotation has occurred within the lifetime of session \"%s\"",
                                session->name);
                goto end;
        case LTTNG_ROTATION_STATE_EXPIRED:
@@ -4884,8 +5184,21 @@ int cmd_rotate_get_info(struct ltt_session *session,
                                        sizeof(info_return->location.local.absolute_path);
                        info_return->location_type =
                                        (int8_t) LTTNG_TRACE_ARCHIVE_LOCATION_TYPE_LOCAL;
+                       fmt_ret = asprintf(&chunk_path,
+                                       "%s/" DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY "/%s",
+                                       session_get_base_path(session),
+                                       session->last_archived_chunk_name);
+                       if (fmt_ret == -1) {
+                               PERROR("Failed to format the path of the last archived trace chunk");
+                               info_return->status = LTTNG_ROTATION_STATUS_ERROR;
+                               cmd_ret = LTTNG_ERR_UNK;
+                               goto end;
+                       }
                        break;
                case CONSUMER_DST_NET:
+               {
+                       uint16_t ctrl_port, data_port;
+
                        current_tracing_path_reply =
                                        info_return->location.relay.relative_path;
                        current_tracing_path_reply_len =
@@ -4904,25 +5217,23 @@ int cmd_rotate_get_info(struct ltt_session *session,
                                goto end;
                        }
 
-                       session_get_net_consumer_ports(session,
-                                       &info_return->location.relay.ports.control,
-                                       &info_return->location.relay.ports.data);
+                       session_get_net_consumer_ports(session, &ctrl_port, &data_port);
+                       info_return->location.relay.ports.control = ctrl_port;
+                       info_return->location.relay.ports.data = data_port;
                        info_return->location_type =
                                        (int8_t) LTTNG_TRACE_ARCHIVE_LOCATION_TYPE_RELAY;
+                       chunk_path = strdup(session->last_chunk_path);
+                       if (!chunk_path) {
+                               ERR("Failed to allocate the path of the last archived trace chunk");
+                               info_return->status = LTTNG_ROTATION_STATUS_ERROR;
+                               cmd_ret = LTTNG_ERR_UNK;
+                               goto end;
+                       }
                        break;
+               }
                default:
                        abort();
                }
-               fmt_ret = asprintf(&chunk_path,
-                               "%s/" DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY "/%s",
-                               session_get_base_path(session),
-                               session->last_archived_chunk_name);
-               if (fmt_ret == -1) {
-                       PERROR("Failed to format the path of the last archived trace chunk");
-                       info_return->status = LTTNG_ROTATION_STATUS_ERROR;
-                       cmd_ret = LTTNG_ERR_UNK;
-                       goto end;
-               }
 
                fmt_ret = lttng_strncpy(current_tracing_path_reply,
                                chunk_path, current_tracing_path_reply_len);
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