Add loglevel enable/disable support

[lttng-ust.git] / liblttng-ust / ltt-events.c

diff --git a/liblttng-ust/ltt-events.c b/liblttng-ust/ltt-events.c
index b67998c3ab310ca68a5ffae5dbb2ccb4cb2387ca..c754d6ff5348e3346fc2765bbaad478a6d834bfc 100644 (file)
--- a/liblttng-ust/ltt-events.c
+++ b/liblttng-ust/ltt-events.c
@@ -14,25 +14,30 @@
 #include <urcu/list.h>
 #include <urcu/hlist.h>
 #include <pthread.h>
-#include <urcu-bp.h>
-#include <urcu/compiler.h>
-#include <urcu/uatomic.h>
 #include <uuid/uuid.h>
-#include <lttng/tracepoint.h>
 #include <errno.h>
 #include <sys/shm.h>
 #include <sys/ipc.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include <urcu-bp.h>
+#include <urcu/compiler.h>
+#include <urcu/uatomic.h>
+#include <urcu/arch.h>
+
+#include <lttng/tracepoint.h>
 #include <lttng/ust-events.h>
-#include <lttng/usterr-signal-safe.h>
+
+#include <usterr-signal-safe.h>
+#include <helper.h>
+#include "error.h"
+
 #include "ltt-tracer.h"
 #include "ltt-tracer-core.h"
 #include "wait.h"
 #include "../libringbuffer/shm.h"
-#include <stdint.h>
-#include <stddef.h>
-#include <urcu/arch.h>
 #include "jhash.h"
-#include <helper.h>
 
 /*
  * The sessions mutex is the centralized mutex across UST tracing
@@ -69,6 +74,7 @@ struct ust_pending_probe {
 };
 
 static void _ltt_event_destroy(struct ltt_event *event);
+static void _ltt_loglevel_destroy(struct loglevel_entry *entry);
 static void _ltt_channel_destroy(struct ltt_channel *chan);
 static int _ltt_event_unregister(struct ltt_event *event);
 static
@@ -130,6 +136,11 @@ int pending_probe_fix_events(const struct lttng_event_desc *desc)
        uint32_t hash = jhash(name, name_len - 1, 0);
        int ret = 0;
 
+       /* TODO:
+        * For this event, we need to lookup the loglevel. If active (in
+        * the active loglevels hash table), we must create the event.
+        */
+
        head = &pending_probe_table[hash & (PENDING_PROBE_HASH_SIZE - 1)];
        cds_hlist_for_each_entry_safe(e, node, p, head, node) {
                struct ltt_event *event;
@@ -169,6 +180,7 @@ struct ltt_session *ltt_session_create(void)
                return NULL;
        CDS_INIT_LIST_HEAD(&session->chan);
        CDS_INIT_LIST_HEAD(&session->events);
+       CDS_INIT_LIST_HEAD(&session->loglevels);
        uuid_generate(session->uuid);
        cds_list_add(&session->list, &sessions);
        return session;
@@ -178,6 +190,7 @@ void ltt_session_destroy(struct ltt_session *session)
 {
        struct ltt_channel *chan, *tmpchan;
        struct ltt_event *event, *tmpevent;
+       struct loglevel_entry *loglevel, *tmploglevel;
        int ret;
 
        CMM_ACCESS_ONCE(session->active) = 0;
@@ -186,6 +199,8 @@ void ltt_session_destroy(struct ltt_session *session)
                WARN_ON(ret);
        }
        synchronize_trace();    /* Wait for in-flight events to complete */
+       cds_list_for_each_entry_safe(loglevel, tmploglevel, &session->loglevels, list)
+               _ltt_loglevel_destroy(loglevel);
        cds_list_for_each_entry_safe(event, tmpevent, &session->events, list)
                _ltt_event_destroy(event);
        cds_list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
@@ -343,28 +358,56 @@ void _ltt_channel_destroy(struct ltt_channel *chan)
        chan->ops->channel_destroy(chan);
 }
 
+int ltt_loglevel_create(struct ltt_channel *chan,
+       struct lttng_ust_event *event_param,
+       struct loglevel_entry **_entry)
+{
+       struct loglevel_entry *entry;
+
+       entry = add_loglevel(event_param->name, chan, event_param);
+       if (!entry || IS_ERR(entry)) {
+               return PTR_ERR(entry);
+       }
+       *_entry = entry;
+       return 0;
+}
+
+static
+void _ltt_loglevel_destroy(struct loglevel_entry *entry)
+{
+       _remove_loglevel(entry);
+}
+
 /*
  * Supports event creation while tracing session is active.
  */
-struct ltt_event *ltt_event_create(struct ltt_channel *chan,
-                                  struct lttng_ust_event *event_param,
-                                  void *filter)
+int ltt_event_create(struct ltt_channel *chan,
+               struct lttng_ust_event *event_param,
+               void *filter,
+               struct ltt_event **_event)
 {
        struct ltt_event *event;
-       int ret;
+       int ret = 0;
 
-       if (chan->used_event_id == -1UL)
+       if (chan->used_event_id == -1UL) {
+               ret = -ENOMEM;
                goto full;
+       }
        /*
         * This is O(n^2) (for each event, the loop is called at event
         * creation). Might require a hash if we have lots of events.
         */
-       cds_list_for_each_entry(event, &chan->session->events, list)
-               if (event->desc && !strcmp(event->desc->name, event_param->name))
+       cds_list_for_each_entry(event, &chan->session->events, list) {
+               if (event->desc && !strcmp(event->desc->name, event_param->name)) {
+                       ret = -EEXIST;
                        goto exist;
+               }
+       }
        event = zmalloc(sizeof(struct ltt_event));
-       if (!event)
+       if (!event) {
+               ret = -ENOMEM;
                goto cache_error;
+       }
        event->chan = chan;
        event->filter = filter;
        /*
@@ -397,6 +440,9 @@ struct ltt_event *ltt_event_create(struct ltt_channel *chan,
                                goto add_pending_error;
                }
                break;
+       case LTTNG_UST_TRACEPOINT_LOGLEVEL:
+               assert(0);
+               break;
        default:
                WARN_ON_ONCE(1);
        }
@@ -406,7 +452,8 @@ struct ltt_event *ltt_event_create(struct ltt_channel *chan,
                        goto statedump_error;
        }
        cds_list_add(&event->list, &chan->session->events);
-       return event;
+       *_event = event;
+       return 0;
 
 statedump_error:
        if (event->desc) {
@@ -421,7 +468,7 @@ register_error:
 cache_error:
 exist:
 full:
-       return NULL;
+       return ret;
 }
 
 /*