Add probe provider unregister function

Also, ensure that enumerations and events are removed from their
respective hashtables when _lttng_{event, enum}_destroy functions are
called.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h
index caf7e63a30642024cd6a2bb5a9638afe21c9b4d7..019b0ebb02af5512c893cfe72147963eec88d3cb 100644 (file)
--- a/include/lttng/ust-events.h
+++ b/include/lttng/ust-events.h
@@ -656,6 +656,7 @@ void synchronize_trace(void);
 
 int lttng_probe_register(struct lttng_probe_desc *desc);
 void lttng_probe_unregister(struct lttng_probe_desc *desc);
+void lttng_probe_provider_unregister_events(struct lttng_probe_desc *desc);
 int lttng_fix_pending_events(void);
 int lttng_probes_init(void);
 void lttng_probes_exit(void);

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index f4a7cccda1db82df02f5e7ae432caf0053a1bb7d..57eb6f7f3a2c745e77191f7ba9b00d1234383f71 100644 (file)
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -788,6 +788,111 @@ void lttng_create_event_if_missing(struct lttng_enabler *enabler)
        }
 }
 
+/*
+ * Iterate over all the UST sessions to unregister and destroy all probes from
+ * the probe provider descriptor received as argument. Must me called with the
+ * ust_lock held.
+ */
+void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_desc)
+{
+       struct cds_hlist_node *node, *tmp_node;
+       struct cds_list_head *sessionsp;
+       struct lttng_session *session;
+       struct cds_hlist_head *head;
+       struct lttng_event *event;
+       int i;
+
+       /* Get handle on list of sessions. */
+       sessionsp = _lttng_get_sessions();
+
+       /*
+        * Iterate over all events in the probe provider descriptions and sessions
+        * to queue the unregistration of the events.
+        */
+       for (i = 0; i < provider_desc->nr_events; i++) {
+               const struct lttng_event_desc *event_desc;
+               const char *event_name;
+               size_t name_len;
+               uint32_t hash;
+
+               event_desc = provider_desc->event_desc[i];
+               event_name = event_desc->name;
+               name_len = strlen(event_name);
+               hash = jhash(event_name, name_len, 0);
+
+               /* Iterate over all session to find the current event description. */
+               cds_list_for_each_entry(session, sessionsp, node) {
+                       /*
+                        * Get the list of events in the hashtable bucket and iterate to
+                        * find the event matching this descriptor.
+                        */
+                       head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+                       cds_hlist_for_each_entry(event, node, head, hlist) {
+                               if (event_desc == event->desc) {
+                                       /* Queue the unregistration of this event. */
+                                       _lttng_event_unregister(event);
+                                       break;
+                               }
+                       }
+               }
+       }
+
+       /* Wait for grace period. */
+       synchronize_trace();
+       /* Prune the unregistration queue. */
+       __tracepoint_probe_prune_release_queue();
+
+       /*
+        * It is now safe to destroy the events and remove them from the event list
+        * and hashtables.
+        */
+       for (i = 0; i < provider_desc->nr_events; i++) {
+               const struct lttng_event_desc *event_desc;
+               const char *event_name;
+               size_t name_len;
+               uint32_t hash;
+
+               event_desc = provider_desc->event_desc[i];
+               event_name = event_desc->name;
+               name_len = strlen(event_name);
+               hash = jhash(event_name, name_len, 0);
+
+               /* Iterate over all sessions to find the current event description. */
+               cds_list_for_each_entry(session, sessionsp, node) {
+                       /*
+                        * Get the list of events in the hashtable bucket and iterate to
+                        * find the event matching this descriptor.
+                        */
+                       head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+                       cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
+                               if (event_desc == event->desc) {
+                                       /* Destroy enums of the current event. */
+                                       for (j = 0; j < event->desc->nr_fields; j++) {
+                                               const struct lttng_enum_desc *enum_desc;
+                                               const struct lttng_event_field *field;
+                                               struct lttng_enum *curr_enum;
+
+                                               field = &(event->desc->fields[j]);
+                                               if (field->type.atype != atype_enum) {
+                                                       continue;
+                                               }
+
+                                               enum_desc = field->type.u.basic.enumeration.desc;
+                                               curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
+                                               if (curr_enum) {
+                                                       _lttng_enum_destroy(curr_enum);
+                                               }
+                                       }
+
+                                       /* Destroy event. */
+                                       _lttng_event_destroy(event);
+                                       break;
+                               }
+                       }
+               }
+       }
+}
+
 /*
  * Create events associated with an enabler (if not already present),
  * and add backward reference from the event to the enabler.
@@ -883,7 +988,11 @@ void _lttng_event_destroy(struct lttng_event *event)
 {
        struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 
+       /* Remove from event list. */
        cds_list_del(&event->node);
+       /* Remove from event hash table. */
+       cds_hlist_del(&event->hlist);
+
        lttng_destroy_context(event->ctx);
        lttng_free_event_filter_runtime(event);
        /* Free event enabler refs */
@@ -897,6 +1006,7 @@ static
 void _lttng_enum_destroy(struct lttng_enum *_enum)
 {
        cds_list_del(&_enum->node);
+       cds_hlist_del(&_enum->hlist);
        free(_enum);
 }