Add lttng_event_get_filter_string() to liblttng-ctl

[lttng-tools.git] / src / lib / lttng-ctl / lttng-ctl.c

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index 9cb2eb4a695648bfb3f4002248ffdeae3a6d6d64..146783fd3e5e09289ebb0d14d0606fd50a1c0aeb 100644 (file)
--- 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.