Send filter expression string to session daemon
[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c
index 4fcd6a4feafdf2eae0b1e4393dd69ecfd6716d5e..4b8d82efe255d398d9e5eba605be42d96cec5421 100644 (file)
@@ -17,6 +17,7 @@
 
 #define _GNU_SOURCE
 #include <assert.h>
+#include <inttypes.h>
 #include <urcu/list.h>
 #include <urcu/uatomic.h>
 
 #include <common/common.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/relayd/relayd.h>
+#include <common/utils.h>
 
 #include "channel.h"
 #include "consumer.h"
 #include "event.h"
-#include "health.h"
+#include "health-sessiond.h"
 #include "kernel.h"
 #include "kernel-consumer.h"
 #include "lttng-sessiond.h"
@@ -110,7 +112,7 @@ static int build_network_session_path(char *dst, size_t size,
                                tmp_urls, kdata_port, tmp_uurl, udata_port);
        } else {
                int dport;
-               if (kuri) {
+               if (kuri || (!kuri && !uuri)) {
                        dport = kdata_port;
                } else {
                        /* No kernel URI, use the UST port. */
@@ -180,6 +182,55 @@ static void list_lttng_channels(int domain, struct ltt_session *session,
        }
 }
 
+/*
+ * Create a list of JUL domain events.
+ *
+ * Return number of events in list on success or else a negative value.
+ */
+static int list_lttng_jul_events(struct jul_domain *dom,
+               struct lttng_event **events)
+{
+       int i = 0, ret = 0;
+       unsigned int nb_event = 0;
+       struct jul_event *event;
+       struct lttng_event *tmp_events;
+       struct lttng_ht_iter iter;
+
+       assert(dom);
+       assert(events);
+
+       DBG3("Listing JUL events");
+
+       nb_event = lttng_ht_get_count(dom->events);
+       if (nb_event == 0) {
+               ret = nb_event;
+               goto error;
+       }
+
+       tmp_events = zmalloc(nb_event * sizeof(*tmp_events));
+       if (!tmp_events) {
+               PERROR("zmalloc JUL events session");
+               ret = -LTTNG_ERR_FATAL;
+               goto error;
+       }
+
+       rcu_read_lock();
+       cds_lfht_for_each_entry(dom->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;
+               i++;
+       }
+       rcu_read_unlock();
+
+       *events = tmp_events;
+       ret = nb_event;
+
+error:
+       assert(nb_event == i);
+       return ret;
+}
+
 /*
  * Create a list of ust global domain events.
  */
@@ -254,6 +305,9 @@ static int list_lttng_ust_global_events(char *channel_name,
                if (uevent->filter) {
                        tmp[i].filter = 1;
                }
+               if (uevent->exclusion) {
+                       tmp[i].exclusion = 1;
+               }
                i++;
        }
 
@@ -460,9 +514,6 @@ static int init_kernel_tracing(struct ltt_kernel_session *session)
        if (session->consumer_fds_sent == 0 && session->consumer != NULL) {
                cds_lfht_for_each_entry(session->consumer->socks->ht, &iter.iter,
                                socket, node.node) {
-                       /* Code flow error */
-                       assert(socket->fd >= 0);
-
                        pthread_mutex_lock(socket->lock);
                        ret = kernel_consumer_send_session(socket, session);
                        pthread_mutex_unlock(socket->lock);
@@ -546,9 +597,10 @@ error:
 /*
  * Connect to the relayd using URI and send the socket to the right consumer.
  */
-static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
+static int send_consumer_relayd_socket(int domain, unsigned int session_id,
                struct lttng_uri *relayd_uri, struct consumer_output *consumer,
-               struct consumer_socket *consumer_sock)
+               struct consumer_socket *consumer_sock,
+               char *session_name, char *hostname, int session_live_timer)
 {
        int ret;
        struct lttcomm_relayd_sock *rsock = NULL;
@@ -560,11 +612,6 @@ static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
        }
        assert(rsock);
 
-       /* If the control socket is connected, network session is ready */
-       if (relayd_uri->stype == LTTNG_STREAM_CONTROL) {
-               session->net_handle = 1;
-       }
-
        /* Set the network sequence index if not set. */
        if (consumer->net_seq_index == (uint64_t) -1ULL) {
                pthread_mutex_lock(&relayd_net_seq_idx_lock);
@@ -579,7 +626,8 @@ static int send_consumer_relayd_socket(int domain, struct ltt_session *session,
 
        /* Send relayd socket to consumer. */
        ret = consumer_send_relayd_socket(consumer_sock, rsock, consumer,
-                       relayd_uri->stype, session->id);
+                       relayd_uri->stype, session_id,
+                       session_name, hostname, session_live_timer);
        if (ret < 0) {
                ret = LTTNG_ERR_ENABLE_CONSUMER_FAIL;
                goto close_sock;
@@ -606,10 +654,11 @@ close_sock:
 error:
        if (ret != LTTNG_OK) {
                /*
-                * On error, nullify the consumer sequence index so streams are not
-                * associated with it once sent to the consumer.
+                * The consumer output for this session should not be used anymore
+                * since the relayd connection failed thus making any tracing or/and
+                * streaming not usable.
                 */
-               uatomic_set(&consumer->net_seq_index, -1);
+               consumer->enabled = 0;
        }
        return ret;
 }
@@ -619,19 +668,20 @@ error:
  * helper function to facilitate sending the information to the consumer for a
  * session.
  */
-static int send_consumer_relayd_sockets(int domain,
-               struct ltt_session *session, struct consumer_output *consumer,
-               struct consumer_socket *sock)
+static int send_consumer_relayd_sockets(int domain, unsigned int session_id,
+               struct consumer_output *consumer, struct consumer_socket *sock,
+               char *session_name, char *hostname, int session_live_timer)
 {
        int ret = LTTNG_OK;
 
-       assert(session);
        assert(consumer);
+       assert(sock);
 
        /* Sending control relayd socket. */
        if (!sock->control_sock_sent) {
-               ret = send_consumer_relayd_socket(domain, session,
-                               &consumer->dst.net.control, consumer, sock);
+               ret = send_consumer_relayd_socket(domain, session_id,
+                               &consumer->dst.net.control, consumer, sock,
+                               session_name, hostname, session_live_timer);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -639,8 +689,9 @@ static int send_consumer_relayd_sockets(int domain,
 
        /* Sending data relayd socket. */
        if (!sock->data_sock_sent) {
-               ret = send_consumer_relayd_socket(domain, session,
-                               &consumer->dst.net.data, consumer, sock);
+               ret = send_consumer_relayd_socket(domain, session_id,
+                               &consumer->dst.net.data, consumer, sock,
+                               session_name, hostname, session_live_timer);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -677,16 +728,17 @@ int cmd_setup_relayd(struct ltt_session *session)
                /* For each consumer socket, send relayd sockets */
                cds_lfht_for_each_entry(usess->consumer->socks->ht, &iter.iter,
                                socket, node.node) {
-                       /* Code flow error */
-                       assert(socket->fd >= 0);
-
                        pthread_mutex_lock(socket->lock);
-                       ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session,
-                                       usess->consumer, socket);
+                       ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_UST, session->id,
+                                       usess->consumer, socket,
+                                       session->name, session->hostname,
+                                       session->live_timer);
                        pthread_mutex_unlock(socket->lock);
                        if (ret != LTTNG_OK) {
                                goto error;
                        }
+                       /* Session is now ready for network streaming. */
+                       session->net_handle = 1;
                }
        }
 
@@ -694,16 +746,17 @@ int cmd_setup_relayd(struct ltt_session *session)
                        && ksess->consumer->enabled) {
                cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
                                socket, node.node) {
-                       /* Code flow error */
-                       assert(socket->fd >= 0);
-
                        pthread_mutex_lock(socket->lock);
-                       ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session,
-                                       ksess->consumer, socket);
+                       ret = send_consumer_relayd_sockets(LTTNG_DOMAIN_KERNEL, session->id,
+                                       ksess->consumer, socket,
+                                       session->name, session->hostname,
+                                       session->live_timer);
                        pthread_mutex_unlock(socket->lock);
                        if (ret != LTTNG_OK) {
                                goto error;
                        }
+                       /* Session is now ready for network streaming. */
+                       session->net_handle = 1;
                }
        }
 
@@ -721,7 +774,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
        struct ltt_kernel_channel *kchan;
 
        /* Open kernel metadata */
-       if (ksess->metadata == NULL) {
+       if (ksess->metadata == NULL && ksess->output_traces) {
                ret = kernel_open_metadata(ksess);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_META_FAIL;
@@ -730,7 +783,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
        }
 
        /* Open kernel metadata stream */
-       if (ksess->metadata_stream_fd < 0) {
+       if (ksess->metadata && ksess->metadata_stream_fd < 0) {
                ret = kernel_open_metadata_stream(ksess);
                if (ret < 0) {
                        ERR("Kernel create metadata stream failed");
@@ -754,7 +807,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
 
        /* Setup kernel consumer socket and send fds to it */
        ret = init_kernel_tracing(ksess);
-       if (ret < 0) {
+       if (ret != 0) {
                ret = LTTNG_ERR_KERN_START_FAIL;
                goto error;
        }
@@ -858,6 +911,25 @@ int cmd_enable_channel(struct ltt_session *session,
 
        rcu_read_lock();
 
+       /*
+        * Don't try to enable a channel if the session has been started at
+        * some point in time before. The tracer does not allow it.
+        */
+       if (session->started) {
+               ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+               goto error;
+       }
+
+       /*
+        * If the session is a live session, remove the switch timer, the
+        * live timer does the same thing but sends also synchronisation
+        * beacons for inactive streams.
+        */
+       if (session->live_timer > 0) {
+               attr->attr.live_timer_interval = session->live_timer;
+               attr->attr.switch_timer_interval = 0;
+       }
+
        switch (domain->type) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -866,7 +938,19 @@ int cmd_enable_channel(struct ltt_session *session,
                kchan = trace_kernel_get_channel_by_name(attr->name,
                                session->kernel_session);
                if (kchan == NULL) {
+                       /*
+                        * Don't try to create a channel if the session
+                        * has been started at some point in time
+                        * before. The tracer does not allow it.
+                        */
+                       if (session->started) {
+                               ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+                               goto error;
+                       }
                        ret = channel_kernel_create(session->kernel_session, attr, wpipe);
+                       if (attr->name[0] != '\0') {
+                               session->kernel_session->has_non_default_channel = 1;
+                       }
                } else {
                        ret = channel_kernel_enable(session->kernel_session, kchan);
                }
@@ -876,18 +960,6 @@ int cmd_enable_channel(struct ltt_session *session,
                }
 
                kernel_wait_quiescent(kernel_tracer_fd);
-
-               /*
-                * If the session was previously started, start as well this newly
-                * created kernel session so the events/channels enabled *after* the
-                * start actually work.
-                */
-               if (session->started && !session->kernel_session->started) {
-                       ret = start_kernel_session(session->kernel_session, wpipe);
-                       if (ret != LTTNG_OK) {
-                               goto error;
-                       }
-               }
                break;
        }
        case LTTNG_DOMAIN_UST:
@@ -898,21 +970,22 @@ int cmd_enable_channel(struct ltt_session *session,
 
                uchan = trace_ust_find_channel_by_name(chan_ht, attr->name);
                if (uchan == NULL) {
+                       /*
+                        * Don't try to create a channel if the session
+                        * has been started at some point in time
+                        * before. The tracer does not allow it.
+                        */
+                       if (session->started) {
+                               ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+                               goto error;
+                       }
                        ret = channel_ust_create(usess, attr, domain->buf_type);
+                       if (attr->name[0] != '\0') {
+                               usess->has_non_default_channel = 1;
+                       }
                } else {
                        ret = channel_ust_enable(usess, uchan);
                }
-
-               /* Start the UST session if the session was already started. */
-               if (session->started && !usess->start_trace) {
-                       ret = ust_app_start_trace_all(usess);
-                       if (ret < 0) {
-                               ret = LTTNG_ERR_UST_START_FAIL;
-                               goto error;
-                       }
-                       ret = LTTNG_OK;
-                       usess->start_trace = 1;
-               }
                break;
        }
        default:
@@ -944,6 +1017,16 @@ int cmd_disable_event(struct ltt_session *session, int domain,
 
                ksess = session->kernel_session;
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (ksess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
                if (kchan == NULL) {
                        ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
@@ -965,6 +1048,16 @@ int cmd_disable_event(struct ltt_session *session, int domain,
 
                usess = session->ust_session;
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (usess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
                                channel_name);
                if (uchan == NULL) {
@@ -981,6 +1074,19 @@ int cmd_disable_event(struct ltt_session *session, int domain,
                                channel_name);
                break;
        }
+       case LTTNG_DOMAIN_JUL:
+       {
+               struct ltt_ust_session *usess = session->ust_session;
+
+               assert(usess);
+
+               ret = event_jul_disable(usess, event_name);
+               if (ret != LTTNG_OK) {
+                       goto error;
+               }
+
+               break;
+       }
 #if 0
        case LTTNG_DOMAIN_UST_EXEC_NAME:
        case LTTNG_DOMAIN_UST_PID:
@@ -1016,6 +1122,16 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
 
                ksess = session->kernel_session;
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (ksess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                kchan = trace_kernel_get_channel_by_name(channel_name, ksess);
                if (kchan == NULL) {
                        ret = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
@@ -1037,6 +1153,16 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
 
                usess = session->ust_session;
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (usess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
                                channel_name);
                if (uchan == NULL) {
@@ -1051,6 +1177,19 @@ int cmd_disable_event_all(struct ltt_session *session, int domain,
 
                DBG3("Disable all UST events in channel %s completed", channel_name);
 
+               break;
+       }
+       case LTTNG_DOMAIN_JUL:
+       {
+               struct ltt_ust_session *usess = session->ust_session;
+
+               assert(usess);
+
+               ret = event_jul_disable_all(usess);
+               if (ret != LTTNG_OK) {
+                       goto error;
+               }
+
                break;
        }
 #if 0
@@ -1076,7 +1215,7 @@ error:
 int cmd_add_context(struct ltt_session *session, int domain,
                char *channel_name, struct lttng_event_context *ctx, int kwpipe)
 {
-       int ret;
+       int ret, chan_kern_created = 0, chan_ust_created = 0;
 
        switch (domain) {
        case LTTNG_DOMAIN_KERNEL:
@@ -1088,8 +1227,8 @@ int cmd_add_context(struct ltt_session *session, int domain,
                        if (ret != LTTNG_OK) {
                                goto error;
                        }
+                       chan_kern_created = 1;
                }
-
                /* Add kernel context to kernel tracer */
                ret = context_kernel_add(session->kernel_session, ctx, channel_name);
                if (ret != LTTNG_OK) {
@@ -1099,14 +1238,15 @@ int cmd_add_context(struct ltt_session *session, int domain,
        case LTTNG_DOMAIN_UST:
        {
                struct ltt_ust_session *usess = session->ust_session;
+               unsigned int chan_count;
+
                assert(usess);
 
-               unsigned int chan_count =
-                       lttng_ht_get_count(usess->domain_global.channels);
+               chan_count = lttng_ht_get_count(usess->domain_global.channels);
                if (chan_count == 0) {
                        struct lttng_channel *attr;
                        /* Create default channel */
-                       attr = channel_new_default_attr(domain);
+                       attr = channel_new_default_attr(domain, usess->buffer_type);
                        if (attr == NULL) {
                                ret = LTTNG_ERR_FATAL;
                                goto error;
@@ -1118,6 +1258,7 @@ int cmd_add_context(struct ltt_session *session, int domain,
                                goto error;
                        }
                        free(attr);
+                       chan_ust_created = 1;
                }
 
                ret = context_ust_add(usess, domain, ctx, channel_name);
@@ -1136,9 +1277,30 @@ int cmd_add_context(struct ltt_session *session, int domain,
                goto error;
        }
 
-       ret = LTTNG_OK;
+       return LTTNG_OK;
 
 error:
+       if (chan_kern_created) {
+               struct ltt_kernel_channel *kchan =
+                       trace_kernel_get_channel_by_name(DEFAULT_CHANNEL_NAME,
+                                       session->kernel_session);
+               /* Created previously, this should NOT fail. */
+               assert(kchan);
+               kernel_destroy_channel(kchan);
+       }
+
+       if (chan_ust_created) {
+               struct ltt_ust_channel *uchan =
+                       trace_ust_find_channel_by_name(
+                                       session->ust_session->domain_global.channels,
+                                       DEFAULT_CHANNEL_NAME);
+               /* Created previously, this should NOT fail. */
+               assert(uchan);
+               /* Remove from the channel list of the session. */
+               trace_ust_delete_channel(session->ust_session->domain_global.channels,
+                               uchan);
+               trace_ust_destroy_channel(uchan);
+       }
        return ret;
 }
 
@@ -1147,7 +1309,10 @@ error:
  */
 int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
                char *channel_name, struct lttng_event *event,
-               struct lttng_filter_bytecode *filter, int wpipe)
+               char *filter_expression,
+               struct lttng_filter_bytecode *filter,
+               struct lttng_event_exclusion *exclusion,
+               int wpipe)
 {
        int ret, channel_created = 0;
        struct lttng_channel *attr;
@@ -1163,10 +1328,22 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
        {
                struct ltt_kernel_channel *kchan;
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (session->kernel_session->has_non_default_channel
+                               && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                kchan = trace_kernel_get_channel_by_name(channel_name,
                                session->kernel_session);
                if (kchan == NULL) {
-                       attr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
+                       attr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
+                                       LTTNG_BUFFER_GLOBAL);
                        if (attr == NULL) {
                                ret = LTTNG_ERR_FATAL;
                                goto error;
@@ -1211,12 +1388,23 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
 
                assert(usess);
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (usess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                /* Get channel from global UST domain */
                uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
                                channel_name);
                if (uchan == NULL) {
                        /* Create default channel */
-                       attr = channel_new_default_attr(LTTNG_DOMAIN_UST);
+                       attr = channel_new_default_attr(LTTNG_DOMAIN_UST,
+                                       usess->buffer_type);
                        if (attr == NULL) {
                                ret = LTTNG_ERR_FATAL;
                                goto error;
@@ -1237,10 +1425,58 @@ int cmd_enable_event(struct ltt_session *session, struct lttng_domain *domain,
                }
 
                /* At this point, the session and channel exist on the tracer */
-               ret = event_ust_enable_tracepoint(usess, uchan, event, filter);
+               ret = event_ust_enable_tracepoint(usess, uchan, event,
+                               filter_expression, filter, exclusion);
+               if (ret != LTTNG_OK) {
+                       goto error;
+               }
+               break;
+       }
+       case LTTNG_DOMAIN_JUL:
+       {
+               struct lttng_event uevent;
+               struct lttng_domain tmp_dom;
+               struct ltt_ust_session *usess = session->ust_session;
+
+               assert(usess);
+
+               /* Create the default JUL tracepoint. */
+               memset(&uevent, 0, sizeof(uevent));
+               uevent.type = LTTNG_EVENT_TRACEPOINT;
+               uevent.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
+               if (is_root) {
+                       strncpy(uevent.name, DEFAULT_SYS_JUL_EVENT_NAME,
+                                       sizeof(uevent.name));
+               } else {
+                       strncpy(uevent.name, DEFAULT_USER_JUL_EVENT_NAME,
+                                       sizeof(uevent.name));
+               }
+               uevent.name[sizeof(uevent.name) - 1] = '\0';
+
+               /*
+                * The domain type is changed because we are about to enable the
+                * default channel and event for the JUL domain that are hardcoded.
+                * This happens in the UST domain.
+                */
+               memcpy(&tmp_dom, domain, sizeof(tmp_dom));
+               tmp_dom.type = LTTNG_DOMAIN_UST;
+
+               ret = cmd_enable_event(session, &tmp_dom, DEFAULT_JUL_CHANNEL_NAME,
+                       &uevent, NULL, NULL, NULL, wpipe);
+               if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_ENABLED) {
+                       goto error;
+               }
+
+               /* The wild card * means that everything should be enabled. */
+               if (strncmp(event->name, "*", 1) == 0 && strlen(event->name) == 1) {
+                       ret = event_jul_enable_all(usess, event);
+               } else {
+                       ret = event_jul_enable(usess, event);
+               }
                if (ret != LTTNG_OK) {
                        goto error;
                }
+
                break;
        }
 #if 0
@@ -1265,6 +1501,7 @@ error:
  */
 int cmd_enable_event_all(struct ltt_session *session,
                struct lttng_domain *domain, char *channel_name, int event_type,
+               char *filter_expression,
                struct lttng_filter_bytecode *filter, int wpipe)
 {
        int ret;
@@ -1282,11 +1519,23 @@ int cmd_enable_event_all(struct ltt_session *session,
 
                assert(session->kernel_session);
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (session->kernel_session->has_non_default_channel
+                               && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                kchan = trace_kernel_get_channel_by_name(channel_name,
                                session->kernel_session);
                if (kchan == NULL) {
                        /* Create default channel */
-                       attr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL);
+                       attr = channel_new_default_attr(LTTNG_DOMAIN_KERNEL,
+                                       LTTNG_BUFFER_GLOBAL);
                        if (attr == NULL) {
                                ret = LTTNG_ERR_FATAL;
                                goto error;
@@ -1345,12 +1594,23 @@ int cmd_enable_event_all(struct ltt_session *session,
 
                assert(usess);
 
+               /*
+                * If a non-default channel has been created in the
+                * session, explicitely require that -c chan_name needs
+                * to be provided.
+                */
+               if (usess->has_non_default_channel && channel_name[0] == '\0') {
+                       ret = LTTNG_ERR_NEED_CHANNEL_NAME;
+                       goto error;
+               }
+
                /* Get channel from global UST domain */
                uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
                                channel_name);
                if (uchan == NULL) {
                        /* Create default channel */
-                       attr = channel_new_default_attr(LTTNG_DOMAIN_UST);
+                       attr = channel_new_default_attr(LTTNG_DOMAIN_UST,
+                                       usess->buffer_type);
                        if (attr == NULL) {
                                ret = LTTNG_ERR_FATAL;
                                goto error;
@@ -1375,7 +1635,8 @@ int cmd_enable_event_all(struct ltt_session *session,
                switch (event_type) {
                case LTTNG_EVENT_ALL:
                case LTTNG_EVENT_TRACEPOINT:
-                       ret = event_ust_enable_all_tracepoints(usess, uchan, filter);
+                       ret = event_ust_enable_all_tracepoints(usess, uchan,
+                               filter_expression, filter);
                        if (ret != LTTNG_OK) {
                                goto error;
                        }
@@ -1390,6 +1651,52 @@ int cmd_enable_event_all(struct ltt_session *session,
                        goto error;
                }
 
+               break;
+       }
+       case LTTNG_DOMAIN_JUL:
+       {
+               struct lttng_event uevent, event;
+               struct lttng_domain tmp_dom;
+               struct ltt_ust_session *usess = session->ust_session;
+
+               assert(usess);
+
+               /* Create the default JUL tracepoint. */
+               uevent.type = LTTNG_EVENT_TRACEPOINT;
+               uevent.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
+               if (is_root) {
+                       strncpy(uevent.name, DEFAULT_SYS_JUL_EVENT_NAME,
+                                       sizeof(uevent.name));
+               } else {
+                       strncpy(uevent.name, DEFAULT_USER_JUL_EVENT_NAME,
+                                       sizeof(uevent.name));
+               }
+               uevent.name[sizeof(uevent.name) - 1] = '\0';
+
+               /*
+                * The domain type is changed because we are about to enable the
+                * default channel and event for the JUL domain that are hardcoded.
+                * This happens in the UST domain.
+                */
+               memcpy(&tmp_dom, domain, sizeof(tmp_dom));
+               tmp_dom.type = LTTNG_DOMAIN_UST;
+
+               ret = cmd_enable_event(session, &tmp_dom, DEFAULT_JUL_CHANNEL_NAME,
+                       &uevent, NULL, NULL, NULL, wpipe);
+               if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_ENABLED) {
+                       goto error;
+               }
+
+               event.loglevel = LTTNG_LOGLEVEL_JUL_ALL;
+               event.loglevel_type = LTTNG_EVENT_LOGLEVEL_ALL;
+               strncpy(event.name, "*", sizeof(event.name));
+               event.name[sizeof(event.name) - 1] = '\0';
+
+               ret = event_jul_enable_all(usess, &event);
+               if (ret != LTTNG_OK) {
+                       goto error;
+               }
+
                break;
        }
 #if 0
@@ -1433,6 +1740,13 @@ ssize_t cmd_list_tracepoints(int domain, struct lttng_event **events)
                        goto error;
                }
                break;
+       case LTTNG_DOMAIN_JUL:
+               nb_events = jul_list_events(events);
+               if (nb_events < 0) {
+                       ret = LTTNG_ERR_UST_LIST_FAIL;
+                       goto error;
+               }
+               break;
        default:
                ret = LTTNG_ERR_UND;
                goto error;
@@ -1481,6 +1795,7 @@ error:
 int cmd_start_trace(struct ltt_session *session)
 {
        int ret;
+       unsigned long nb_chan = 0;
        struct ltt_kernel_session *ksession;
        struct ltt_ust_session *usess;
 
@@ -1496,6 +1811,21 @@ int cmd_start_trace(struct ltt_session *session)
                goto error;
        }
 
+       /*
+        * Starting a session without channel is useless since after that it's not
+        * possible to enable channel thus inform the client.
+        */
+       if (usess && usess->domain_global.channels) {
+               nb_chan += lttng_ht_get_count(usess->domain_global.channels);
+       }
+       if (ksession) {
+               nb_chan += ksession->channel_count;
+       }
+       if (!nb_chan) {
+               ret = LTTNG_ERR_NO_CHANNEL;
+               goto error;
+       }
+
        session->enabled = 1;
 
        /* Kernel tracing */
@@ -1549,7 +1879,7 @@ int cmd_stop_trace(struct ltt_session *session)
        session->enabled = 0;
 
        /* Kernel tracer */
-       if (ksession) {
+       if (ksession && ksession->started) {
                DBG("Stop kernel tracing");
 
                /* Flush metadata if exist */
@@ -1579,7 +1909,7 @@ int cmd_stop_trace(struct ltt_session *session)
                ksession->started = 0;
        }
 
-       if (usess) {
+       if (usess && usess->start_trace) {
                usess->start_trace = 0;
 
                ret = ust_app_stop_trace_all(usess);
@@ -1589,8 +1919,6 @@ int cmd_stop_trace(struct ltt_session *session)
                }
        }
 
-       session->started = 0;
-
        ret = LTTNG_OK;
 
 error:
@@ -1664,18 +1992,13 @@ error:
  * Command LTTNG_CREATE_SESSION processed by the client thread.
  */
 int cmd_create_session_uri(char *name, struct lttng_uri *uris,
-               size_t nb_uri, lttng_sock_cred *creds)
+               size_t nb_uri, lttng_sock_cred *creds, unsigned int live_timer)
 {
        int ret;
        struct ltt_session *session;
 
        assert(name);
-
-       /* No URIs is not possible. */
-       if (uris == NULL) {
-               ret = LTTNG_ERR_SESSION_FAIL;
-               goto session_error;
-       }
+       assert(creds);
 
        /*
         * Verify if the session already exist
@@ -1707,6 +2030,7 @@ int cmd_create_session_uri(char *name, struct lttng_uri *uris,
        session = session_find_by_name(name);
        assert(session);
 
+       session->live_timer = live_timer;
        /* Create default consumer output for the session not yet created. */
        session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
        if (session->consumer == NULL) {
@@ -1714,9 +2038,15 @@ int cmd_create_session_uri(char *name, struct lttng_uri *uris,
                goto consumer_error;
        }
 
-       ret = cmd_set_consumer_uri(0, session, nb_uri, uris);
-       if (ret != LTTNG_OK) {
-               goto consumer_error;
+       if (uris) {
+               ret = cmd_set_consumer_uri(0, session, nb_uri, uris);
+               if (ret != LTTNG_OK) {
+                       goto consumer_error;
+               }
+               session->output_traces = 1;
+       } else {
+               session->output_traces = 0;
+               DBG2("Session %s created with no output", session->name);
        }
 
        session->consumer->enabled = 1;
@@ -1730,6 +2060,72 @@ find_error:
        return ret;
 }
 
+/*
+ * Command LTTNG_CREATE_SESSION_SNAPSHOT processed by the client thread.
+ */
+int cmd_create_session_snapshot(char *name, struct lttng_uri *uris,
+               size_t nb_uri, lttng_sock_cred *creds)
+{
+       int ret;
+       struct ltt_session *session;
+       struct snapshot_output *new_output = NULL;
+
+       assert(name);
+       assert(creds);
+
+       /*
+        * Create session in no output mode with URIs set to NULL. The uris we've
+        * received are for a default snapshot output if one.
+        */
+       ret = cmd_create_session_uri(name, NULL, 0, creds, -1);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
+
+       /* Get the newly created session pointer back. This should NEVER fail. */
+       session = session_find_by_name(name);
+       assert(session);
+
+       /* Flag session for snapshot mode. */
+       session->snapshot_mode = 1;
+
+       /* Skip snapshot output creation if no URI is given. */
+       if (nb_uri == 0) {
+               goto end;
+       }
+
+       new_output = snapshot_output_alloc();
+       if (!new_output) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error_snapshot_alloc;
+       }
+
+       ret = snapshot_output_init_with_uri(DEFAULT_SNAPSHOT_MAX_SIZE, NULL,
+                       uris, nb_uri, session->consumer, new_output, &session->snapshot);
+       if (ret < 0) {
+               if (ret == -ENOMEM) {
+                       ret = LTTNG_ERR_NOMEM;
+               } else {
+                       ret = LTTNG_ERR_INVALID;
+               }
+               goto error_snapshot;
+       }
+
+       rcu_read_lock();
+       snapshot_add_output(&session->snapshot, new_output);
+       rcu_read_unlock();
+
+end:
+       return LTTNG_OK;
+
+error_snapshot:
+       snapshot_output_destroy(new_output);
+error_snapshot_alloc:
+       session_destroy(session);
+error:
+       return ret;
+}
+
 /*
  * Command LTTNG_DESTROY_SESSION processed by the client thread.
  */
@@ -1789,7 +2185,14 @@ int cmd_calibrate(int domain, struct lttng_calibrate *calibrate)
        {
                struct lttng_kernel_calibrate kcalibrate;
 
-               kcalibrate.type = calibrate->type;
+               switch (calibrate->type) {
+               case LTTNG_CALIBRATE_FUNCTION:
+               default:
+                       /* Default and only possible calibrate option. */
+                       kcalibrate.type = LTTNG_KERNEL_CALIBRATE_KRETPROBE;
+                       break;
+               }
+
                ret = kernel_calibrate(kernel_tracer_fd, &kcalibrate);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_ENABLE_FAIL;
@@ -1801,7 +2204,14 @@ int cmd_calibrate(int domain, struct lttng_calibrate *calibrate)
        {
                struct lttng_ust_calibrate ucalibrate;
 
-               ucalibrate.type = calibrate->type;
+               switch (calibrate->type) {
+               case LTTNG_CALIBRATE_FUNCTION:
+               default:
+                       /* Default and only possible calibrate option. */
+                       ucalibrate.type = LTTNG_UST_CALIBRATE_TRACEPOINT;
+                       break;
+               }
+
                ret = ust_app_calibrate_glb(&ucalibrate);
                if (ret < 0) {
                        ret = LTTNG_ERR_UST_CALIBRATE_FAIL;
@@ -1827,7 +2237,7 @@ int cmd_register_consumer(struct ltt_session *session, int domain,
                const char *sock_path, struct consumer_data *cdata)
 {
        int ret, sock;
-       struct consumer_socket *socket;
+       struct consumer_socket *socket = NULL;
 
        assert(session);
        assert(cdata);
@@ -1851,13 +2261,15 @@ int cmd_register_consumer(struct ltt_session *session, int domain,
                        ret = LTTNG_ERR_CONNECT_FAIL;
                        goto error;
                }
+               cdata->cmd_sock = sock;
 
-               socket = consumer_allocate_socket(sock);
+               socket = consumer_allocate_socket(&cdata->cmd_sock);
                if (socket == NULL) {
                        ret = close(sock);
                        if (ret < 0) {
                                PERROR("close register consumer");
                        }
+                       cdata->cmd_sock = -1;
                        ret = LTTNG_ERR_FATAL;
                        goto error;
                }
@@ -1887,9 +2299,12 @@ int cmd_register_consumer(struct ltt_session *session, int domain,
                goto error;
        }
 
-       ret = LTTNG_OK;
+       return LTTNG_OK;
 
 error:
+       if (socket) {
+               consumer_destroy_socket(socket);
+       }
        return ret;
 }
 
@@ -1910,6 +2325,10 @@ ssize_t cmd_list_domains(struct ltt_session *session,
        if (session->ust_session != NULL) {
                DBG3("Listing domains found UST global domain");
                nb_dom++;
+
+               if (session->ust_session->domain_jul.being_used) {
+                       nb_dom++;
+               }
        }
 
        *domains = zmalloc(nb_dom * sizeof(struct lttng_domain));
@@ -1927,6 +2346,12 @@ ssize_t cmd_list_domains(struct ltt_session *session,
                (*domains)[index].type = LTTNG_DOMAIN_UST;
                (*domains)[index].buf_type = session->ust_session->buffer_type;
                index++;
+
+               if (session->ust_session->domain_jul.being_used) {
+                       (*domains)[index].type = LTTNG_DOMAIN_JUL;
+                       (*domains)[index].buf_type = session->ust_session->buffer_type;
+                       index++;
+               }
        }
 
        return nb_dom;
@@ -2017,6 +2442,12 @@ ssize_t cmd_list_events(int domain, struct ltt_session *session,
                }
                break;
        }
+       case LTTNG_DOMAIN_JUL:
+               if (session->ust_session) {
+                       nb_event = list_lttng_jul_events(
+                                       &session->ust_session->domain_jul, events);
+               }
+               break;
        default:
                ret = LTTNG_ERR_UND;
                goto error;
@@ -2078,13 +2509,15 @@ void cmd_list_lttng_sessions(struct lttng_session *sessions, uid_t uid,
                strncpy(sessions[i].name, session->name, NAME_MAX);
                sessions[i].name[NAME_MAX - 1] = '\0';
                sessions[i].enabled = session->enabled;
+               sessions[i].snapshot_mode = session->snapshot_mode;
+               sessions[i].live_timer_interval = session->live_timer;
                i++;
        }
 }
 
 /*
  * Command LTTNG_DATA_PENDING returning 0 if the data is NOT pending meaning
- * ready for trace analysis (or anykind of reader) or else 1 for pending data.
+ * ready for trace analysis (or any kind of reader) or else 1 for pending data.
  */
 int cmd_data_pending(struct ltt_session *session)
 {
@@ -2123,6 +2556,548 @@ error:
        return ret;
 }
 
+/*
+ * Command LTTNG_SNAPSHOT_ADD_OUTPUT from the lttng ctl library.
+ *
+ * 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)
+{
+       int ret;
+       struct snapshot_output *new_output;
+
+       assert(session);
+       assert(output);
+
+       DBG("Cmd snapshot add output for session %s", session->name);
+
+       /*
+        * Permission denied to create an output if the session is not
+        * set in no output mode.
+        */
+       if (session->output_traces) {
+               ret = LTTNG_ERR_EPERM;
+               goto error;
+       }
+
+       /* Only one output is allowed until we have the "tee" feature. */
+       if (session->snapshot.nb_output == 1) {
+               ret = LTTNG_ERR_SNAPSHOT_OUTPUT_EXIST;
+               goto error;
+       }
+
+       new_output = snapshot_output_alloc();
+       if (!new_output) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       ret = snapshot_output_init(output->max_size, output->name,
+                       output->ctrl_url, output->data_url, session->consumer, new_output,
+                       &session->snapshot);
+       if (ret < 0) {
+               if (ret == -ENOMEM) {
+                       ret = LTTNG_ERR_NOMEM;
+               } else {
+                       ret = LTTNG_ERR_INVALID;
+               }
+               goto free_error;
+       }
+
+       rcu_read_lock();
+       snapshot_add_output(&session->snapshot, new_output);
+       if (id) {
+               *id = new_output->id;
+       }
+       rcu_read_unlock();
+
+       return LTTNG_OK;
+
+free_error:
+       snapshot_output_destroy(new_output);
+error:
+       return ret;
+}
+
+/*
+ * Command LTTNG_SNAPSHOT_DEL_OUTPUT from lib lttng ctl.
+ *
+ * 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)
+{
+       int ret;
+       struct snapshot_output *sout = NULL;
+
+       assert(session);
+       assert(output);
+
+       rcu_read_lock();
+
+       /*
+        * Permission denied to create an output if the session is not
+        * set in no output mode.
+        */
+       if (session->output_traces) {
+               ret = LTTNG_ERR_EPERM;
+               goto error;
+       }
+
+       if (output->id) {
+               DBG("Cmd snapshot del output id %" PRIu32 " for session %s", output->id,
+                               session->name);
+               sout = snapshot_find_output_by_id(output->id, &session->snapshot);
+       } else if (*output->name != '\0') {
+               DBG("Cmd snapshot del output name %s for session %s", output->name,
+                               session->name);
+               sout = snapshot_find_output_by_name(output->name, &session->snapshot);
+       }
+       if (!sout) {
+               ret = LTTNG_ERR_INVALID;
+               goto error;
+       }
+
+       snapshot_delete_output(&session->snapshot, sout);
+       snapshot_output_destroy(sout);
+       ret = LTTNG_OK;
+
+error:
+       rcu_read_unlock();
+       return ret;
+}
+
+/*
+ * Command LTTNG_SNAPSHOT_LIST_OUTPUT from lib lttng ctl.
+ *
+ * If no output is available, outputs is untouched and 0 is returned.
+ *
+ * Return the size of the newly allocated outputs or a negative LTTNG_ERR code.
+ */
+ssize_t cmd_snapshot_list_outputs(struct ltt_session *session,
+               struct lttng_snapshot_output **outputs)
+{
+       int ret, idx = 0;
+       struct lttng_snapshot_output *list;
+       struct lttng_ht_iter iter;
+       struct snapshot_output *output;
+
+       assert(session);
+       assert(outputs);
+
+       DBG("Cmd snapshot list outputs for session %s", session->name);
+
+       /*
+        * Permission denied to create an output if the session is not
+        * set in no output mode.
+        */
+       if (session->output_traces) {
+               ret = LTTNG_ERR_EPERM;
+               goto error;
+       }
+
+       if (session->snapshot.nb_output == 0) {
+               ret = 0;
+               goto error;
+       }
+
+       list = zmalloc(session->snapshot.nb_output * sizeof(*list));
+       if (!list) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       /* Copy list from session to the new list object. */
+       cds_lfht_for_each_entry(session->snapshot.output_ht->ht, &iter.iter,
+                       output, node.node) {
+               assert(output->consumer);
+               list[idx].id = output->id;
+               list[idx].max_size = output->max_size;
+               strncpy(list[idx].name, output->name, sizeof(list[idx].name));
+               if (output->consumer->type == CONSUMER_DST_LOCAL) {
+                       strncpy(list[idx].ctrl_url, output->consumer->dst.trace_path,
+                                       sizeof(list[idx].ctrl_url));
+               } else {
+                       /* Control URI. */
+                       ret = uri_to_str_url(&output->consumer->dst.net.control,
+                                       list[idx].ctrl_url, sizeof(list[idx].ctrl_url));
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_NOMEM;
+                               goto free_error;
+                       }
+
+                       /* Data URI. */
+                       ret = uri_to_str_url(&output->consumer->dst.net.data,
+                                       list[idx].data_url, sizeof(list[idx].data_url));
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_NOMEM;
+                               goto free_error;
+                       }
+               }
+               idx++;
+       }
+
+       *outputs = list;
+       return session->snapshot.nb_output;
+
+free_error:
+       free(list);
+error:
+       return -ret;
+}
+
+/*
+ * Send relayd sockets from snapshot output to consumer. Ignore request if the
+ * snapshot output is *not* set with a remote destination.
+ *
+ * Return 0 on success or a LTTNG_ERR code.
+ */
+static int set_relayd_for_snapshot(struct consumer_output *consumer,
+               struct snapshot_output *snap_output, struct ltt_session *session)
+{
+       int ret = LTTNG_OK;
+       struct lttng_ht_iter iter;
+       struct consumer_socket *socket;
+
+       assert(consumer);
+       assert(snap_output);
+       assert(session);
+
+       DBG2("Set relayd object from snapshot output");
+
+       /* Ignore if snapshot consumer output is not network. */
+       if (snap_output->consumer->type != CONSUMER_DST_NET) {
+               goto error;
+       }
+
+       /*
+        * 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,
+                       socket, node.node) {
+               ret = send_consumer_relayd_sockets(0, session->id,
+                               snap_output->consumer, socket,
+                               session->name, session->hostname,
+                               session->live_timer);
+               if (ret != LTTNG_OK) {
+                       rcu_read_unlock();
+                       goto error;
+               }
+       }
+       rcu_read_unlock();
+
+error:
+       return ret;
+}
+
+/*
+ * Record a kernel snapshot.
+ *
+ * Return LTTNG_OK on success or a LTTNG_ERR code.
+ */
+static int record_kernel_snapshot(struct ltt_kernel_session *ksess,
+               struct snapshot_output *output, struct ltt_session *session,
+               int wait, int nb_streams)
+{
+       int ret;
+
+       assert(ksess);
+       assert(output);
+       assert(session);
+
+       /* Get the datetime for the snapshot output directory. */
+       ret = utils_get_current_time_str("%Y%m%d-%H%M%S", output->datetime,
+                       sizeof(output->datetime));
+       if (!ret) {
+               ret = LTTNG_ERR_INVALID;
+               goto error;
+       }
+
+       /*
+        * 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) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       ret = set_relayd_for_snapshot(ksess->consumer, output, session);
+       if (ret != LTTNG_OK) {
+               goto error_snapshot;
+       }
+
+       ret = kernel_snapshot_record(ksess, output, wait, nb_streams);
+       if (ret != LTTNG_OK) {
+               goto error_snapshot;
+       }
+
+       ret = LTTNG_OK;
+
+error_snapshot:
+       /* Clean up copied sockets so this output can use some other later on. */
+       consumer_destroy_output_sockets(output->consumer);
+error:
+       return ret;
+}
+
+/*
+ * Record a UST snapshot.
+ *
+ * Return 0 on success or a LTTNG_ERR error code.
+ */
+static int record_ust_snapshot(struct ltt_ust_session *usess,
+               struct snapshot_output *output, struct ltt_session *session,
+               int wait, int nb_streams)
+{
+       int ret;
+
+       assert(usess);
+       assert(output);
+       assert(session);
+
+       /* Get the datetime for the snapshot output directory. */
+       ret = utils_get_current_time_str("%Y%m%d-%H%M%S", output->datetime,
+                       sizeof(output->datetime));
+       if (!ret) {
+               ret = LTTNG_ERR_INVALID;
+               goto error;
+       }
+
+       /*
+        * 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) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       ret = set_relayd_for_snapshot(usess->consumer, output, session);
+       if (ret != LTTNG_OK) {
+               goto error_snapshot;
+       }
+
+       ret = ust_app_snapshot_record(usess, output, wait, nb_streams);
+       if (ret < 0) {
+               switch (-ret) {
+               case EINVAL:
+                       ret = LTTNG_ERR_INVALID;
+                       break;
+               case ENODATA:
+                       ret = LTTNG_ERR_SNAPSHOT_NODATA;
+                       break;
+               default:
+                       ret = LTTNG_ERR_SNAPSHOT_FAIL;
+                       break;
+               }
+               goto error_snapshot;
+       }
+
+       ret = LTTNG_OK;
+
+error_snapshot:
+       /* Clean up copied sockets so this output can use some other later on. */
+       consumer_destroy_output_sockets(output->consumer);
+error:
+       return ret;
+}
+
+/*
+ * Returns the total number of streams for a session or a negative value
+ * on error.
+ */
+static unsigned int get_total_nb_stream(struct ltt_session *session)
+{
+       unsigned int total_streams = 0;
+
+       if (session->kernel_session) {
+               struct ltt_kernel_session *ksess = session->kernel_session;
+
+               total_streams += ksess->stream_count_global;
+       }
+
+       if (session->ust_session) {
+               struct ltt_ust_session *usess = session->ust_session;
+
+               total_streams += ust_app_get_nb_stream(usess);
+       }
+
+       return total_streams;
+}
+
+/*
+ * Command LTTNG_SNAPSHOT_RECORD from lib lttng ctl.
+ *
+ * The wait parameter is ignored so this call always wait for the snapshot to
+ * complete before returning.
+ *
+ * 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)
+{
+       int ret = LTTNG_OK;
+       unsigned int use_tmp_output = 0;
+       struct snapshot_output tmp_output;
+       unsigned int nb_streams, snapshot_success = 0;
+
+       assert(session);
+
+       DBG("Cmd snapshot record for session %s", session->name);
+
+       /*
+        * Permission denied to create an output if the session is not
+        * set in no output mode.
+        */
+       if (session->output_traces) {
+               ret = LTTNG_ERR_EPERM;
+               goto error;
+       }
+
+       /* The session needs to be started at least once. */
+       if (!session->started) {
+               ret = LTTNG_ERR_START_SESSION_ONCE;
+               goto error;
+       }
+
+       /* Use temporary output for the session. */
+       if (output && *output->ctrl_url != '\0') {
+               ret = snapshot_output_init(output->max_size, output->name,
+                               output->ctrl_url, output->data_url, session->consumer,
+                               &tmp_output, NULL);
+               if (ret < 0) {
+                       if (ret == -ENOMEM) {
+                               ret = LTTNG_ERR_NOMEM;
+                       } else {
+                               ret = LTTNG_ERR_INVALID;
+                       }
+                       goto error;
+               }
+               /* Use the global session count for the temporary snapshot. */
+               tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+               use_tmp_output = 1;
+       }
+
+       /*
+        * Get the total number of stream of that session which is used by the
+        * maximum size of the snapshot feature.
+        */
+       nb_streams = get_total_nb_stream(session);
+
+       if (session->kernel_session) {
+               struct ltt_kernel_session *ksess = session->kernel_session;
+
+               if (use_tmp_output) {
+                       ret = record_kernel_snapshot(ksess, &tmp_output, session,
+                                       wait, nb_streams);
+                       if (ret != LTTNG_OK) {
+                               goto error;
+                       }
+                       snapshot_success = 1;
+               } else {
+                       struct snapshot_output *sout;
+                       struct lttng_ht_iter iter;
+
+                       rcu_read_lock();
+                       cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
+                                       &iter.iter, sout, node.node) {
+                               /*
+                                * Make a local copy of the output and assign the possible
+                                * temporary value given by the caller.
+                                */
+                               memset(&tmp_output, 0, sizeof(tmp_output));
+                               memcpy(&tmp_output, sout, sizeof(tmp_output));
+
+                               /* Use temporary max size. */
+                               if (output->max_size != (uint64_t) -1ULL) {
+                                       tmp_output.max_size = output->max_size;
+                               }
+
+                               /* Use temporary name. */
+                               if (*output->name != '\0') {
+                                       strncpy(tmp_output.name, output->name,
+                                                       sizeof(tmp_output.name));
+                               }
+
+                               tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+
+                               ret = record_kernel_snapshot(ksess, &tmp_output,
+                                               session, wait, nb_streams);
+                               if (ret != LTTNG_OK) {
+                                       rcu_read_unlock();
+                                       goto error;
+                               }
+                               snapshot_success = 1;
+                       }
+                       rcu_read_unlock();
+               }
+       }
+
+       if (session->ust_session) {
+               struct ltt_ust_session *usess = session->ust_session;
+
+               if (use_tmp_output) {
+                       ret = record_ust_snapshot(usess, &tmp_output, session,
+                                       wait, nb_streams);
+                       if (ret != LTTNG_OK) {
+                               goto error;
+                       }
+                       snapshot_success = 1;
+               } else {
+                       struct snapshot_output *sout;
+                       struct lttng_ht_iter iter;
+
+                       rcu_read_lock();
+                       cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
+                                       &iter.iter, sout, node.node) {
+                               /*
+                                * Make a local copy of the output and assign the possible
+                                * temporary value given by the caller.
+                                */
+                               memset(&tmp_output, 0, sizeof(tmp_output));
+                               memcpy(&tmp_output, sout, sizeof(tmp_output));
+
+                               /* Use temporary max size. */
+                               if (output->max_size != (uint64_t) -1ULL) {
+                                       tmp_output.max_size = output->max_size;
+                               }
+
+                               /* Use temporary name. */
+                               if (*output->name != '\0') {
+                                       strncpy(tmp_output.name, output->name,
+                                                       sizeof(tmp_output.name));
+                               }
+
+                               tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
+
+                               ret = record_ust_snapshot(usess, &tmp_output, session,
+                                               wait, nb_streams);
+                               if (ret != LTTNG_OK) {
+                                       rcu_read_unlock();
+                                       goto error;
+                               }
+                               snapshot_success = 1;
+                       }
+                       rcu_read_unlock();
+               }
+       }
+
+       if (snapshot_success) {
+               session->snapshot.nb_snapshot++;
+       } else {
+               ret = LTTNG_ERR_SNAPSHOT_FAIL;
+       }
+
+error:
+       return ret;
+}
+
 /*
  * Init command subsystem.
  */
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