Add ustctl_snapshot_sample_positions ustctl command

[lttng-ust.git] / libringbuffer / frontend.h

diff --git a/libringbuffer/frontend.h b/libringbuffer/frontend.h
index 8c8517086828d1fc5c9cf2bf2c780b8a933fc653..a2f74596eb9c06f319236309d2f36cdae2eaca99 100644 (file)
--- a/libringbuffer/frontend.h
+++ b/libringbuffer/frontend.h
@@ -131,6 +131,11 @@ extern int lib_ring_buffer_snapshot(struct lttng_ust_lib_ring_buffer *buf,
                                    unsigned long *consumed,
                                    unsigned long *produced,
                                    struct lttng_ust_shm_handle *handle);
+extern int lib_ring_buffer_snapshot_sample_positions(
+                                   struct lttng_ust_lib_ring_buffer *buf,
+                                   unsigned long *consumed,
+                                   unsigned long *produced,
+                                   struct lttng_ust_shm_handle *handle);
 extern void lib_ring_buffer_move_consumer(struct lttng_ust_lib_ring_buffer *buf,
                                          unsigned long consumed_new,
                                          struct lttng_ust_shm_handle *handle);
@@ -162,9 +167,14 @@ static inline
 void lib_ring_buffer_put_next_subbuf(struct lttng_ust_lib_ring_buffer *buf,
                                     struct lttng_ust_shm_handle *handle)
 {
+       struct channel *chan;
+
+       chan = shmp(handle, buf->backend.chan);
+       if (!chan)
+               return;
        lib_ring_buffer_put_subbuf(buf, handle);
-       lib_ring_buffer_move_consumer(buf, subbuf_align(buf->cons_snapshot,
-                                                       shmp(handle, buf->backend.chan)), handle);
+       lib_ring_buffer_move_consumer(buf, subbuf_align(buf->cons_snapshot, chan),
+                       handle);
 }
 
 extern void channel_reset(struct channel *chan);