From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Sat, 29 Aug 2015 22:31:03 +0000 (-0400)
Subject: Add lttng_event_get_filter_string() to liblttng-ctl
X-Git-Tag: v2.8.0-rc1~142
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=d31d3e8cf774b98a8ed46b8c7f6273364360f246

Add lttng_event_get_filter_string() to liblttng-ctl

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/include/lttng/event.h b/include/lttng/event.h
index 06a63ccba..a85f0f3b5 100644
--- a/include/lttng/event.h
+++ b/include/lttng/event.h
@@ -295,6 +295,18 @@ struct lttng_event_field {
 extern int lttng_list_events(struct lttng_handle *handle,
 		const char *channel_name, struct lttng_event **events);
 
+/*
+ * Get the filter string of a specific LTTng event.
+ *
+ * If the call is successful, then the filter string's address is put
+ * in *filter_string. If the event has no filter string, *filter_string
+ * is set to NULL. The caller does NOT own *filter_string.
+ *
+ * Returns 0 on success, or a negative LTTng error code on error.
+ */
+extern int lttng_event_get_filter_string(struct lttng_event *event,
+		const char **filter_string);
+
 /*
  * List the available tracepoints of a specific lttng domain.
  *
diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 12bdf17cd..800859b8e 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -326,7 +326,7 @@ static int list_lttng_ust_global_events(char *channel_name,
 	node = lttng_ht_iter_get_node_str(&iter);
 	if (node == NULL) {
 		ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
-		goto error;
+		goto end;
 	}
 
 	uchan = caa_container_of(&node->node, struct ltt_ust_channel, node.node);
@@ -335,7 +335,7 @@ static int list_lttng_ust_global_events(char *channel_name,
 	if (nb_event == 0) {
 		ret = nb_event;
 		*total_size = 0;
-		goto error;
+		goto end;
 	}
 
 	DBG3("Listing UST global %d events", nb_event);
@@ -350,6 +350,12 @@ static int list_lttng_ust_global_events(char *channel_name,
 		increment_extended_len(uevent->filter_expression,
 			&extended_len);
 	}
+	if (nb_event == 0) {
+		/* All events are internal, skip. */
+		ret = 0;
+		*total_size = 0;
+		goto end;
+	}
 
 	*total_size = nb_event * sizeof(struct lttng_event) + extended_len;
 	tmp = zmalloc(*total_size);
@@ -407,8 +413,7 @@ static int list_lttng_ust_global_events(char *channel_name,
 
 	ret = nb_event;
 	*events = tmp;
-
-error:
+end:
 	rcu_read_unlock();
 	return ret;
 }
diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index 9cb2eb4a6..146783fd3 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -1782,6 +1782,38 @@ error:
 	return ret;
 }
 
+int lttng_event_get_filter_string(struct lttng_event *event,
+	const char **filter_string)
+{
+	int ret = 0;
+	struct lttcomm_event_extended_header *ext_header;
+
+	if (!event || !filter_string) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	ext_header = event->extended.ptr;
+
+	if (!ext_header) {
+		/*
+		 * This can happen since the lttng_event structure is
+		 * used for other tasks where this pointer is never set.
+		 */
+		*filter_string = NULL;
+		goto end;
+	}
+
+	if (ext_header->filter_len) {
+		*filter_string = ((const char *) (ext_header)) +
+			sizeof(*ext_header);
+	} else {
+		*filter_string = NULL;
+	}
+
+end:
+	return ret;
+}
 
 /*
  * Sets the tracing_group variable with name.