Improve UST context code

Better breakdown of code when adding context to an event or channel.
This also fix possible memory leak of ust context data structure.

Signed-off-by: David Goulet <david.goulet@polymtl.ca>

diff --git a/lttng-sessiond/context.c b/lttng-sessiond/context.c
index a61ca8dcea2ad4ab36ab7f3dbe70223493352513..081e05430ba1e9b44c95b536fc9dd7152db991d0 100644 (file)
--- a/lttng-sessiond/context.c
+++ b/lttng-sessiond/context.c
@@ -151,6 +151,83 @@ error:
        return ret;
 }
 
+/*
+ * Add UST context to channel.
+ */
+static int add_uctx_to_channel(struct ltt_ust_session *usess, int domain,
+               struct ltt_ust_channel *uchan, struct lttng_event_context *ctx)
+{
+       int ret;
+       struct ltt_ust_context *uctx;
+
+       /* Create ltt UST context */
+       uctx = trace_ust_create_context(ctx);
+       if (uctx == NULL) {
+               ret = LTTCOMM_FATAL;
+               goto error;
+       }
+
+       switch (domain) {
+       case LTTNG_DOMAIN_UST:
+               ret = ust_app_add_ctx_channel_glb(usess, uchan, uctx);
+               if (ret < 0) {
+                       goto error;
+               }
+               break;
+       default:
+               ret = LTTCOMM_NOT_IMPLEMENTED;
+               goto error;
+       }
+
+       /* Add ltt UST context node to ltt UST channel */
+       hashtable_add_unique(uchan->ctx, &uctx->node);
+
+       return LTTCOMM_OK;
+
+error:
+       free(uctx);
+       return ret;
+}
+
+/*
+ * Add UST context to event.
+ */
+static int add_uctx_to_event(struct ltt_ust_session *usess, int domain,
+               struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent,
+               struct lttng_event_context *ctx)
+{
+       int ret;
+       struct ltt_ust_context *uctx;
+
+       /* Create ltt UST context */
+       uctx = trace_ust_create_context(ctx);
+       if (uctx == NULL) {
+               ret = LTTCOMM_FATAL;
+               goto error;
+       }
+
+       switch (domain) {
+       case LTTNG_DOMAIN_UST:
+               ret = ust_app_add_ctx_event_glb(usess, uchan, uevent, uctx);
+               if (ret < 0) {
+                       goto error;
+               }
+               break;
+       default:
+               ret = LTTCOMM_NOT_IMPLEMENTED;
+               goto error;
+       }
+
+       /* Add ltt UST context node to ltt UST event */
+       hashtable_add_unique(uevent->ctx, &uctx->node);
+
+       return LTTCOMM_OK;
+
+error:
+       free(uctx);
+       return ret;
+}
+
 /*
  * Add kernel context to tracer.
  */
@@ -207,8 +284,11 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
        struct cds_lfht *chan_ht;
        struct ltt_ust_channel *uchan = NULL;
        struct ltt_ust_event *uevent = NULL;
-       struct ltt_ust_context *uctx;
 
+       /*
+        * Define which channel's hashtable to use from the domain or quit if
+        * unknown domain.
+        */
        switch (domain) {
        case LTTNG_DOMAIN_UST:
                chan_ht = usess->domain_global.channels;
@@ -221,6 +301,7 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
                goto error;
        }
 
+       /* Do we have an event name */
        if (strlen(event_name) != 0) {
                have_event = 1;
        }
@@ -243,59 +324,45 @@ int context_ust_add(struct ltt_ust_session *usess, int domain,
                }
        }
 
-       /* Create ltt UST context */
-       uctx = trace_ust_create_context(ctx);
-       if (uctx == NULL) {
-               ret = LTTCOMM_FATAL;
-               goto error;
-       }
-
        /* At this point, we have 4 possibilities */
 
-       if (uchan && uevent) {                  /* Add ctx to event in channel */
-               ret = ust_app_add_ctx_event_glb(usess, uchan, uevent, uctx);
+       if (uchan && uevent) {                          /* Add ctx to event in channel */
+               ret = add_uctx_to_event(usess, domain, uchan, uevent, ctx);
        } else if (uchan && !have_event) {      /* Add ctx to channel */
-               ret = ust_app_add_ctx_channel_glb(usess, uchan, uctx);
+               ret = add_uctx_to_channel(usess, domain, uchan, ctx);
        } else if (!uchan && have_event) {      /* Add ctx to event */
+               /* Add context to event without having the channel name */
                cds_lfht_for_each_entry(chan_ht, &iter, uchan, node) {
                        uevent = trace_ust_find_event_by_name(uchan->events, event_name);
                        if (uevent != NULL) {
-                               ret = ust_app_add_ctx_event_glb(usess, uchan, uevent, uctx);
+                               ret = add_uctx_to_event(usess, domain, uchan, uevent, ctx);
                                /*
                                 * LTTng UST does not allowed the same event to be registered
                                 * multiple time in different or the same channel. So, if we
-                                * found our event in the first place, no need to continue.
+                                * found our event, we stop.
                                 */
                                goto end;
                        }
                }
                ret = LTTCOMM_UST_EVENT_NOT_FOUND;
-               goto error_free_ctx;
-       } else if (!uchan && !have_event) {     /* Add ctx to all events, all channels */
+               goto error;
+       } else if (!uchan && !have_event) {     /* Add ctx all events, all channels */
+               /* For all channels */
                cds_lfht_for_each_entry(chan_ht, &iter, uchan, node) {
-                       ret = ust_app_add_ctx_channel_glb(usess, uchan, uctx);
+                       ret = add_uctx_to_channel(usess, domain, uchan, ctx);
                        if (ret < 0) {
-                               /* Add failed so uctx was not added. We can keep it. */
+                               ERR("Context added to channel %s failed", uchan->name);
                                continue;
                        }
+
+                       /* For all events in channel */
                        cds_lfht_for_each_entry(uchan->events, &uiter, uevent, node) {
-                               ret = ust_app_add_ctx_event_glb(usess, uchan, uevent, uctx);
+                               ret = add_uctx_to_event(usess, domain, uchan, uevent, ctx);
                                if (ret < 0) {
-                                       /* Add failed so uctx was not added. We can keep it. */
+                                       ERR("Context add to event %s in channel %s failed",
+                                                       uevent->attr.name, uchan->name);
                                        continue;
                                }
-                               /* Create ltt UST context */
-                               uctx = trace_ust_create_context(ctx);
-                               if (uctx == NULL) {
-                                       ret = LTTCOMM_FATAL;
-                                       goto error;
-                               }
-                       }
-                       /* Create ltt UST context */
-                       uctx = trace_ust_create_context(ctx);
-                       if (uctx == NULL) {
-                               ret = LTTCOMM_FATAL;
-                               goto error;
                        }
                }
        }
@@ -304,16 +371,14 @@ end:
        switch (ret) {
        case -EEXIST:
                ret = LTTCOMM_UST_CONTEXT_EXIST;
-               goto error_free_ctx;
+               goto error;
        case -ENOMEM:
                ret = LTTCOMM_FATAL;
-               goto error_free_ctx;
+               goto error;
        }
 
        return LTTCOMM_OK;
 
-error_free_ctx:
-       free(uctx);
 error:
        return ret;
 }

diff --git a/lttng-sessiond/ust-app.c b/lttng-sessiond/ust-app.c
index 4f65553c8385d770c6f9c9a1e517a21e8ba0c06c..2ed9d002d49f444df38662f3cf26e335d10f0b41 100644 (file)
--- a/lttng-sessiond/ust-app.c
+++ b/lttng-sessiond/ust-app.c
@@ -2195,9 +2195,6 @@ int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
                }
        }
 
-       /* Add ltt UST context node to ltt UST channel */
-       hashtable_add_unique(uchan->ctx, &uctx->node);
-
        rcu_read_unlock();
        return ret;
 }
@@ -2248,9 +2245,6 @@ int ust_app_add_ctx_event_glb(struct ltt_ust_session *usess,
                }
        }
 
-       /* Add ltt UST context node to ltt UST event */
-       hashtable_add_unique(uevent->ctx, &uctx->node);
-
        rcu_read_unlock();
        return ret;
 }