diff mbox series

[v2,2/3] libtracefs: Add new API for getting synth event name

Message ID 20211209104524.5354-3-y.karadz@gmail.com (mailing list archive)
State Accepted
Headers show
Series libtracefs: APIs for inspecting hist/synth objects | expand

Commit Message

Yordan Karadzhov Dec. 9, 2021, 10:45 a.m. UTC 
We add:
const char *tracefs_synth_get_name(struct tracefs_synth *)

The new API can be valuable in a number of different scenarios.
For example, when the user works with multiple synth events and
wants to print an adequate error message in a case of a failure.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 Documentation/libtracefs-synth2.txt | 14 +++++++++++---
 include/tracefs.h                   |  1 +
 src/tracefs-hist.c                  | 11 +++++++++++
 3 files changed, 23 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
index 1cb07c8..569819a 100644
--- a/Documentation/libtracefs-synth2.txt
+++ b/Documentation/libtracefs-synth2.txt
@@ -3,8 +3,9 @@  libtracefs(3)
 
 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 - Creation of synthetic events
+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 - Creation of synthetic events
 
 SYNOPSIS
 --------
@@ -25,6 +26,7 @@  int tracefs_synth_snapshot(struct tracefs_synth pass:[*]synth,
 int tracefs_synth_save(struct tracefs_synth pass:[*]synth,
 		       enum tracefs_synth_handler type, const char pass:[*]var,
 		       char pass:[**]save_fields);
+const char *tracefs_synth_get_name(struct tracefs_synth pass:[*]synth);
 --
 
 DESCRIPTION
@@ -87,9 +89,15 @@  then saven the given _save_fields_ list. The fields will be stored in the histog
 "hist" file of the event that can be retrieved with *tracefs_event_file_read*(3).
 _var_ changes. _var_ must be one of the _name_ elements used in *tracefs_synth_add_end_field*(3).
 
+*tracefs_synth_get_name*() returns the name of the 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*().
+
 RETURN VALUE
 ------------
-Returns zero on success or -1 on error.
+*tracefs_synth_get_name*() returns a string owned by the synth event object.
+
+All other functions return zero on success or -1 on error.
 
 ERRORS
 ------
diff --git a/include/tracefs.h b/include/tracefs.h
index b874d3f..967690f 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -502,6 +502,7 @@  enum tracefs_synth_handler {
 	TRACEFS_SYNTH_HANDLE_CHANGE,
 };
 
+const char *tracefs_synth_get_name(struct tracefs_synth *synth);
 struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
 					  const char *name,
 					  const char *start_system,
diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 59ac5e4..6051ecc 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -702,6 +702,17 @@  struct tracefs_synth {
 	int			arg_cnt;
 };
 
+ /*
+ * tracefs_synth_get_name - get the name of the synthetic event
+ * @synth: The synthetic event to get the name for
+ *
+ * Returns name string owned by @synth on success, or NULL on error.
+ */
+const char *tracefs_synth_get_name(struct tracefs_synth *synth)
+{
+	return synth ? synth->name : NULL;
+}
+
 static void action_free(struct action *action)
 {
 	free(action->handle_field);