Rotate command

[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 e5f068a0cd9515408a34b4621201e8b75f714a81..ccf315d8901efdcb2e04e50a4de9e85e1073bca2 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -33,6 +33,7 @@
 #include "kernel-consumer.h"
 #include "kern-modules.h"
 #include "utils.h"
+#include "rotate.h"
 
 /*
  * Key used to reference a channel between the sessiond and the consumer. This
@@ -1133,3 +1134,88 @@ int kernel_supports_ring_buffer_snapshot_sample_positions(int tracer_fd)
 error:
        return ret;
 }
+
+/*
+ * Rotate a kernel session.
+ *
+ * Return 0 on success or else return a LTTNG_ERR code.
+ */
+int kernel_rotate_session(struct ltt_session *session)
+{
+       int ret;
+       struct consumer_socket *socket;
+       struct lttng_ht_iter iter;
+       struct ltt_kernel_session *ksess = session->kernel_session;
+
+       assert(ksess);
+       assert(ksess->consumer);
+
+       DBG("Rotate kernel session %s started (session %" PRIu64 ")",
+                       session->name, session->id);
+
+       rcu_read_lock();
+
+       /*
+        * 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;
+
+               /*
+                * Account the metadata channel first to make sure the
+                * number of channels waiting for a rotation cannot
+                * reach 0 before we complete the iteration over all
+                * the channels.
+                */
+               ret = rotate_add_channel_pending(ksess->metadata->fd,
+                               LTTNG_DOMAIN_KERNEL, session);
+               if (ret < 0) {
+                       ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                       goto error;
+               }
+
+               /* For each channel, ask the consumer to rotate it. */
+               cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
+                       ret = rotate_add_channel_pending(chan->key,
+                                       LTTNG_DOMAIN_KERNEL, session);
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                               goto error;
+                       }
+
+                       DBG("Rotate channel %" PRIu64 ", session %s", chan->key, session->name);
+                       ret = consumer_rotate_channel(socket, chan->key,
+                                       ksess->uid, ksess->gid, ksess->consumer,
+                                       ksess->consumer->subdir,
+                                       /* is_metadata_channel */ false,
+                                       session->rotate_count,
+                                       &session->rotate_pending_relay);
+                       if (ret < 0) {
+                               ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                               goto error;
+                       }
+               }
+
+               /*
+                * Rotate the metadata channel.
+                */
+               ret = consumer_rotate_channel(socket, ksess->metadata->fd,
+                               ksess->uid, ksess->gid, ksess->consumer,
+                               ksess->consumer->subdir,
+                               /* is_metadata_channel */ true,
+                               session->rotate_count,
+                               &session->rotate_pending_relay);
+               if (ret < 0) {
+                       ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
+                       goto error;
+               }
+       }
+
+       ret = LTTNG_OK;
+
+error:
+       rcu_read_unlock();
+       return ret;
+}