@@ -6,7 +6,8 @@ NAME
tracefs_synth_create, tracefs_synth_destroy, tracefs_synth_echo_cmd, tracefs_synth_complete,
tracefs_synth_get_start_hist, tracefs_synth_trace, tracefs_synth_snapshot,
tracefs_synth_get_name, tracefs_synth_raw_fmt, tracefs_synth_show_event,
-tracefs_synth_show_start_hist, tracefs_synth_show_end_hist - Creation of synthetic events
+tracefs_synth_show_start_hist, tracefs_synth_show_end_hist, tracefs_synth_get_event
+- Creation of synthetic events
SYNOPSIS
--------
@@ -32,7 +33,7 @@ int tracefs_synth_raw_fmt(struct trace_seq pass:[*]seq, struct tracefs_synth pas
const char *tracefs_synth_show_event(struct tracefs_synth pass:[*]synth);
const char *tracefs_synth_show_start_hist(struct tracefs_synth pass:[*]synth);
const char *tracefs_synth_show_end_hist(struct tracefs_synth pass:[*]synth);
-
+struct tep_event pass:[*]*tracefs_synth_get_event*(struct tep_handle pass:[*]_tep_, struct tracefs_synth pass:[*]_synth_);
--
DESCRIPTION
@@ -114,11 +115,19 @@ and is freed with the event by *tracefs_synth_free*().
synthetic event or NULL on error. The returned string belongs to the synth event object
and is freed with the event by *tracefs_synth_free*().
+The *tracefs_synth_get_event*() function returns a tep event, describing the given synthetic
+event. The API detects any newly created or removed dynamic events. The returned pointer to
+tep event is controlled by @tep and must not be freed.
+
RETURN VALUE
------------
*tracefs_synth_get_name*(), *tracefs_synth_show_event*(), *tracefs_synth_show_start_hist*()
and *tracefs_synth_show_end_hist*() return a string owned by the synth event object.
+The *tracefs_synth_get_event*() function returns a pointer to a tep event or NULL in case of an
+error or if the requested synthetic event is missing. The returned pointer to tep event is
+controlled by @tep and must not be freed.
+
All other functions return zero on success or -1 on error.
ERRORS
@@ -116,5 +116,7 @@ int trace_load_events(struct tep_handle *tep,
const char *tracing_dir, const char *system);
int trace_rescan_events(struct tep_handle *tep,
const char *tracing_dir, const char *system);
+struct tep_event *get_tep_event(struct tep_handle *tep,
+ const char *system, const char *name);
#endif /* _TRACE_FS_LOCAL_H */
@@ -564,5 +564,7 @@ const char *tracefs_synth_show_end_hist(struct tracefs_synth *synth);
struct tracefs_synth *tracefs_sql(struct tep_handle *tep, const char *name,
const char *sql_buffer, char **err);
+struct tep_event *
+tracefs_synth_get_event(struct tep_handle *tep, struct tracefs_synth *synth);
#endif /* _TRACE_FS_H */
@@ -765,23 +765,8 @@ error:
struct tep_event *
tracefs_dynevent_get_event(struct tep_handle *tep, struct tracefs_dynevent *dynevent)
{
- struct tep_event *event;
-
if (!tep || !dynevent || !dynevent->event)
return NULL;
- /* Check if event exists in the system */
- if (!tracefs_event_file_exists(NULL, dynevent->system, dynevent->event, "format"))
- return NULL;
-
- /* If the dynamic event is already loaded in the tep, return it */
- event = tep_find_event_by_name(tep, dynevent->system, dynevent->event);
- if (event)
- return event;
-
- /* Try to load any new events from the given system */
- if (trace_rescan_events(tep, NULL, dynevent->system))
- return NULL;
-
- return tep_find_event_by_name(tep, dynevent->system, dynevent->event);
+ return get_tep_event(tep, dynevent->system, dynevent->event);
}
@@ -752,6 +752,27 @@ __hidden int trace_load_events(struct tep_handle *tep,
return load_events(tep, tracing_dir, system, false);
}
+__hidden struct tep_event *get_tep_event(struct tep_handle *tep,
+ const char *system, const char *name)
+{
+ struct tep_event *event;
+
+ /* Check if event exists in the system */
+ if (!tracefs_event_file_exists(NULL, system, name, "format"))
+ return NULL;
+
+ /* If the event is already loaded in the tep, return it */
+ event = tep_find_event_by_name(tep, system, name);
+ if (event)
+ return event;
+
+ /* Try to load any new events from the given system */
+ if (trace_rescan_events(tep, NULL, system))
+ return NULL;
+
+ return tep_find_event_by_name(tep, system, name);
+}
+
static int read_header(struct tep_handle *tep, const char *tracing_dir)
{
struct stat st;
@@ -2197,3 +2197,21 @@ int tracefs_synth_echo_cmd(struct trace_seq *seq,
}
return ret;
}
+
+/**
+ * tracefs_synth_get_event - return tep event representing the given synthetic event
+ * @tep: a handle to the trace event parser context that holds the events
+ * @synth: a synthetic event context, describing given synthetic event.
+ *
+ * Returns a pointer to a tep event describing the given synthetic event. The pointer
+ * is managed by the @tep handle and must not be freed. In case of an error, or in case
+ * the requested synthetic event is missing in the @tep handler - NULL is returned.
+ */
+struct tep_event *
+tracefs_synth_get_event(struct tep_handle *tep, struct tracefs_synth *synth)
+{
+ if (!tep || !synth || !synth->name)
+ return NULL;
+
+ return get_tep_event(tep, SYNTHETIC_GROUP, synth->name);
+}
A new API is proposed, to get tep event descriptor for given synthetic event: tracefs_synth_get_event () The API implementation gets derived from the implementation of the existing API tracefs_dynevent_get_event(). It can detect any newly created or removed synthetic events. Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com> --- Documentation/libtracefs-synth2.txt | 13 +++++++++++-- include/tracefs-local.h | 2 ++ include/tracefs.h | 2 ++ src/tracefs-dynevents.c | 17 +---------------- src/tracefs-events.c | 21 +++++++++++++++++++++ src/tracefs-hist.c | 18 ++++++++++++++++++ 6 files changed, 55 insertions(+), 18 deletions(-)