Fix: add-context cannot be performed after a session has been started

[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 9e761958a19ffc1138f62186c9ddecc47b9515c4..1a3c22a6c8f87715dc85c878ec5b0c3443d7d1e3 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -34,6 +34,7 @@
 #include <lttng/trigger/trigger-internal.h>
 #include <lttng/condition/condition.h>
 #include <lttng/action/action.h>
+#include <lttng/channel.h>
 #include <lttng/channel-internal.h>
 #include <common/string-utils/string-utils.h>
 
@@ -277,6 +278,7 @@ static ssize_t list_lttng_channels(enum lttng_domain_type domain,
                                chan_exts[i].lost_packets = lost_packets;
                                chan_exts[i].monitor_timer_interval =
                                                extended->monitor_timer_interval;
+                               chan_exts[i].blocking_timeout = 0;
                                i++;
                        }
                }
@@ -324,6 +326,8 @@ static ssize_t list_lttng_channels(enum lttng_domain_type domain,
 
                        chan_exts[i].monitor_timer_interval =
                                        uchan->monitor_timer_interval;
+                       chan_exts[i].blocking_timeout =
+                               uchan->attr.u.s.blocking_timeout;
 
                        ret = get_ust_runtime_stats(session, uchan,
                                        &discarded_events, &lost_packets);
@@ -903,6 +907,8 @@ error:
 
 /*
  * Connect to the relayd using URI and send the socket to the right consumer.
+ *
+ * The consumer socket lock must be held by the caller.
  */
 static int send_consumer_relayd_socket(enum lttng_domain_type domain,
                unsigned int session_id, struct lttng_uri *relayd_uri,
@@ -916,7 +922,7 @@ static int send_consumer_relayd_socket(enum lttng_domain_type domain,
        /* Connect to relayd and make version check if uri is the control. */
        ret = create_connect_relayd(relayd_uri, &rsock, consumer);
        if (ret != LTTNG_OK) {
-               goto error;
+               goto relayd_comm_error;
        }
        assert(rsock);
 
@@ -956,10 +962,6 @@ static int send_consumer_relayd_socket(enum lttng_domain_type domain,
         */
 
 close_sock:
-       (void) relayd_close(rsock);
-       free(rsock);
-
-error:
        if (ret != LTTNG_OK) {
                /*
                 * The consumer output for this session should not be used anymore
@@ -968,6 +970,10 @@ error:
                 */
                consumer->enabled = 0;
        }
+       (void) relayd_close(rsock);
+       free(rsock);
+
+relayd_comm_error:
        return ret;
 }
 
@@ -975,6 +981,8 @@ error:
  * Send both relayd sockets to a specific consumer and domain.  This is a
  * helper function to facilitate sending the information to the consumer for a
  * session.
+ *
+ * The consumer socket lock must be held by the caller.
  */
 static int send_consumer_relayd_sockets(enum lttng_domain_type domain,
                unsigned int session_id, struct consumer_output *consumer,
@@ -1354,6 +1362,30 @@ int cmd_enable_channel(struct ltt_session *session,
                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) {
+                       /* 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);
+               }
+               break;
+       }
+       case LTTNG_DOMAIN_UST:
+       case LTTNG_DOMAIN_JUL:
+       case LTTNG_DOMAIN_LOG4J:
+       case LTTNG_DOMAIN_PYTHON:
+               break;
+       default:
+               ret = LTTNG_ERR_UNKNOWN_DOMAIN;
+               goto error;
+       }
+
        switch (domain->type) {
        case LTTNG_DOMAIN_KERNEL:
        {
@@ -1622,6 +1654,16 @@ int cmd_add_context(struct ltt_session *session, enum lttng_domain_type domain,
        int ret, chan_kern_created = 0, chan_ust_created = 0;
        char *app_ctx_provider_name = NULL, *app_ctx_name = NULL;
 
+       /*
+        * Don't try to add a context if the session has been started at
+        * some point in time before. The tracer does not allow it and would
+        * result in a corrupted trace.
+        */
+       if (session->has_been_started) {
+               ret = LTTNG_ERR_TRACE_ALREADY_STARTED;
+               goto end;
+       }
+
        if (ctx->ctx == LTTNG_EVENT_CONTEXT_APP_CONTEXT) {
                app_ctx_provider_name = ctx->u.app_ctx.provider_name;
                app_ctx_name = ctx->u.app_ctx.ctx_name;
@@ -3522,7 +3564,6 @@ int cmd_regenerate_statedump(struct ltt_session *session)
                ret = LTTNG_ERR_SESSION_NOT_STARTED;
                goto end;
        }
-       ret = 0;
 
        if (session->kernel_session) {
                ret = kernctl_session_regenerate_statedump(
@@ -3679,10 +3720,12 @@ static int set_relayd_for_snapshot(struct consumer_output *consumer,
        rcu_read_lock();
        cds_lfht_for_each_entry(snap_output->consumer->socks->ht, &iter.iter,
                        socket, node.node) {
+               pthread_mutex_lock(socket->lock);
                ret = send_consumer_relayd_sockets(0, session->id,
                                snap_output->consumer, socket,
                                session->name, session->hostname,
                                session->live_timer);
+               pthread_mutex_unlock(socket->lock);
                if (ret != LTTNG_OK) {
                        rcu_read_unlock();
                        goto error;