trackers: add sessiond tracker list implementation

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

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index b5c4a5e1267b5ae5fbe95cd70723ed2afb5710ab..2626e98b259f46eeebbeee69be8bc1935cb43dfa 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -1289,6 +1289,7 @@ enum lttng_error_code kernel_snapshot_record(
        struct lttng_ht_iter iter;
        struct ltt_kernel_metadata *saved_metadata;
        char *trace_path = NULL;
+       size_t consumer_path_offset = 0;
 
        assert(ksess);
        assert(ksess->consumer);
@@ -1315,7 +1316,7 @@ enum lttng_error_code kernel_snapshot_record(
        }
 
        trace_path = setup_channel_trace_path(ksess->consumer,
-                       DEFAULT_KERNEL_TRACE_DIR);
+                       DEFAULT_KERNEL_TRACE_DIR, &consumer_path_offset);
        if (!trace_path) {
                status = LTTNG_ERR_INVALID;
                goto error;
@@ -1338,7 +1339,7 @@ enum lttng_error_code kernel_snapshot_record(
                cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
                        status = consumer_snapshot_channel(socket, chan->key, output, 0,
                                        ksess->uid, ksess->gid,
-                                       trace_path, wait,
+                                       &trace_path[consumer_path_offset], wait,
                                        nb_packets_per_stream);
                        if (status != LTTNG_OK) {
                                (void) kernel_consumer_destroy_metadata(socket,
@@ -1349,7 +1350,8 @@ enum lttng_error_code kernel_snapshot_record(
 
                /* Snapshot metadata, */
                status = consumer_snapshot_channel(socket, ksess->metadata->key, output,
-                               1, ksess->uid, ksess->gid, trace_path, wait, 0);
+                               1, ksess->uid, ksess->gid, &trace_path[consumer_path_offset],
+                               wait, 0);
                if (status != LTTNG_OK) {
                        goto error_consumer;
                }
@@ -1443,9 +1445,10 @@ int kernel_supports_ring_buffer_packet_sequence_number(void)
        }
 
        /*
-        * Packet sequence number was introduced in 2.8
+        * Packet sequence number was introduced in LTTng 2.8,
+        * lttng-modules ABI 2.1.
         */
-       if (abi.major >= 2 && abi.minor >= 8) {
+       if (abi.major >= 2 && abi.minor >= 1) {
                /* Supported */
                ret = 1;
        } else {
@@ -1645,3 +1648,83 @@ bool kernel_tracer_is_initialized(void)
 {
        return kernel_tracer_fd >= 0;
 }
+
+/*
+ *  Clear a kernel session.
+ *
+ * Return LTTNG_OK on success or else an LTTng error code.
+ */
+enum lttng_error_code kernel_clear_session(struct ltt_session *session)
+{
+       int ret;
+       enum lttng_error_code status = LTTNG_OK;
+       struct consumer_socket *socket;
+       struct lttng_ht_iter iter;
+       struct ltt_kernel_session *ksess = session->kernel_session;
+
+       assert(ksess);
+       assert(ksess->consumer);
+
+       DBG("Clear kernel session %s (session %" PRIu64 ")",
+                       session->name, session->id);
+
+       rcu_read_lock();
+
+       if (ksess->active) {
+               ERR("Expecting inactive session %s (%" PRIu64 ")", session->name, session->id);
+               status = LTTNG_ERR_FATAL;
+               goto end;
+       }
+
+       /*
+        * Note that this loop will end after one iteration given that there is
+        * only one kernel consumer.
+        */
+       cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
+                       socket, node.node) {
+               struct ltt_kernel_channel *chan;
+
+               /* For each channel, ask the consumer to clear it. */
+               cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+                       DBG("Clear kernel channel %" PRIu64 ", session %s",
+                                       chan->key, session->name);
+                       ret = consumer_clear_channel(socket, chan->key);
+                       if (ret < 0) {
+                               goto error;
+                       }
+               }
+
+               if (!ksess->metadata) {
+                       /*
+                        * Nothing to do for the metadata.
+                        * This is a snapshot session.
+                        * The metadata is genererated on the fly.
+                        */
+                       continue;
+               }
+
+               /*
+                * Clear the metadata channel.
+                * Metadata channel is not cleared per se but we still need to
+                * perform a rotation operation on it behind the scene.
+                */
+               ret = consumer_clear_channel(socket, ksess->metadata->key);
+               if (ret < 0) {
+                       goto error;
+               }
+       }
+
+       goto end;
+error:
+       switch (-ret) {
+       case LTTCOMM_CONSUMERD_RELAYD_CLEAR_DISALLOWED:
+             status = LTTNG_ERR_CLEAR_RELAY_DISALLOWED;
+             break;
+       default:
+             status = LTTNG_ERR_CLEAR_FAIL_CONSUMER;
+             break;
+       }
+end:
+       rcu_read_unlock();
+       return status;
+}