Implement PID tracker content listing

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

diff --git a/src/bin/lttng-sessiond/trace-ust.c b/src/bin/lttng-sessiond/trace-ust.c
index e74ed62ba894862394576d9991ba93e41ede9489..2740d0f803a6d3393a2431dac53e85e85f21e846 100644 (file)
--- a/src/bin/lttng-sessiond/trace-ust.c
+++ b/src/bin/lttng-sessiond/trace-ust.c
@@ -808,6 +808,50 @@ end:
        return retval;
 }
 
+/*
+ * Called with session lock held.
+ */
+ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
+               int32_t **_pids)
+{
+       struct ust_pid_tracker_node *tracker_node;
+       struct lttng_ht_iter iter;
+       unsigned long count, i = 0;
+       long approx[2];
+       int32_t *pids;
+       int ret = 0;
+
+       if (!session->pid_tracker.ht) {
+               /* Tracker disabled. Set first entry to -1. */
+               pids = zmalloc(sizeof(*pids));
+               if (!pids) {
+                       ret = -1;
+                       goto end;
+               }
+               pids[0] = -1;
+               *_pids = pids;
+               return 1;
+       }
+
+       rcu_read_lock();
+       cds_lfht_count_nodes(session->pid_tracker.ht->ht,
+               &approx[0], &count, &approx[1]);
+       pids = zmalloc(sizeof(*pids) * count);
+       if (!pids) {
+               ret = -1;
+               goto end;
+       }
+       cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
+                       &iter.iter, tracker_node, node.node) {
+               pids[i++] = tracker_node->node.key;
+       }
+       *_pids = pids;
+       ret = count;
+end:
+       rcu_read_unlock();
+       return ret;
+}
+
 /*
  * RCU safe free context structure.
  */