[PATCH v18 01/18] trace-cmd: Implement new lib API: tracecmd_local_events_system()

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

From: Tzvetomir Stoyanov <tstoyanov@vmware.com>

The new tracecmd lib API tracecmd_local_events_system() creates
a tep handler and initializes it with the events of the specified
subsystems. It can be used instead of tracecmd_local_events(), when
not all events are going to be parsed using that tep handler.

Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
---
 include/trace-cmd/trace-cmd.h |   4 +-
 lib/trace-cmd/trace-util.c    | 102 +++++++++++++++++++++++-----------
 2 files changed, 72 insertions(+), 34 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 13afce7..9363a26 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -27,8 +27,10 @@ extern int tracecmd_disable_plugins;
 char **tracecmd_event_systems(const char *tracing_dir);
 char **tracecmd_system_events(const char *tracing_dir, const char *system);
 struct tep_handle *tracecmd_local_events(const char *tracing_dir);
+struct tep_handle *tracecmd_local_events_system(const char *tracing_dir,
+						const char * const *sys_names);
 int tracecmd_fill_local_events(const char *tracing_dir,
-			       struct tep_handle *pevent, int *parsing_failures);
+			       struct tep_handle *tep, int *parsing_failures);
 char **tracecmd_local_plugins(const char *tracing_dir);
 
 char **tracecmd_add_list(char **list, const char *name, int len);
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index b5bb0d5..e93225f 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -616,39 +616,20 @@ static int read_header(struct tep_handle *pevent, const char *events_dir)
 	return ret;
 }
 
-/**
- * tracecmd_local_events - create a pevent from the events on system
- * @tracing_dir: The directory that contains the events.
- *
- * Returns a pevent structure that contains the pevents local to
- * the system.
- */
-struct tep_handle *tracecmd_local_events(const char *tracing_dir)
+static bool contains(const char *name, const char * const *names)
 {
-	struct tep_handle *pevent = NULL;
-
-	pevent = tep_alloc();
-	if (!pevent)
-		return NULL;
-
-	if (tracecmd_fill_local_events(tracing_dir, pevent, NULL)) {
-		tep_free(pevent);
-		pevent = NULL;
-	}
-
-	return pevent;
+	if (!names)
+		return false;
+	for (; *names; names++)
+		if (strcmp(name, *names) == 0)
+			return true;
+	return false;
 }
 
-/**
- * tracecmd_fill_local_events - Fill a pevent with the events on system
- * @tracing_dir: The directory that contains the events.
- * @pevent: Allocated pevent which will be filled
- * @parsing_failures: return number of failures while parsing the event files
- *
- * Returns whether the operation succeeded
- */
-int tracecmd_fill_local_events(const char *tracing_dir,
-			       struct tep_handle *pevent, int *parsing_failures)
+static int tracecmd_fill_local_events_system(const char *tracing_dir,
+					     struct tep_handle *tep,
+					     const char * const *sys_names,
+					     int *parsing_failures)
 {
 	struct dirent *dent;
 	char *events_dir;
@@ -677,7 +658,7 @@ int tracecmd_fill_local_events(const char *tracing_dir,
 		goto out_free;
 	}
 
-	ret = read_header(pevent, events_dir);
+	ret = read_header(tep, events_dir);
 	if (ret < 0) {
 		ret = -1;
 		goto out_free;
@@ -690,7 +671,8 @@ int tracecmd_fill_local_events(const char *tracing_dir,
 		if (strcmp(name, ".") == 0 ||
 		    strcmp(name, "..") == 0)
 			continue;
-
+		if (sys_names && !contains(name, sys_names))
+			continue;
 		sys = append_file(events_dir, name);
 		ret = stat(sys, &st);
 		if (ret < 0 || !S_ISDIR(st.st_mode)) {
@@ -698,7 +680,7 @@ int tracecmd_fill_local_events(const char *tracing_dir,
 			continue;
 		}
 
-		ret = load_events(pevent, name, sys);
+		ret = load_events(tep, name, sys);
 
 		free(sys);
 
@@ -716,6 +698,60 @@ int tracecmd_fill_local_events(const char *tracing_dir,
 	return ret;
 }
 
+/**
+ * tracecmd_local_events_system - create a tep from the events of the specified subsystem
+ *
+ * @tracing_dir: The directory that contains the events
+ * @sys_name: Array of system names, to load the events from
+ * The last element from the array must be NULL
+ *
+ * Returns a tep structure that contains the tep local to
+ * the system
+ */
+struct tep_handle *tracecmd_local_events_system(const char *tracing_dir,
+						const char * const *sys_names)
+{
+	struct tep_handle *tep = NULL;
+
+	tep = tep_alloc();
+	if (!tep)
+		return NULL;
+
+	if (tracecmd_fill_local_events_system(tracing_dir, tep, sys_names, NULL)) {
+		tep_free(tep);
+		tep = NULL;
+	}
+
+	return tep;
+}
+
+/**
+ * tracecmd_local_events - create a pevent from the events on system
+ * @tracing_dir: The directory that contains the events
+ *
+ * Returns a pevent structure that contains the pevents local to
+ * the system
+ */
+struct tep_handle *tracecmd_local_events(const char *tracing_dir)
+{
+	return tracecmd_local_events_system(tracing_dir, NULL);
+}
+
+/**
+ * tracecmd_fill_local_events - Fill a pevent with the events on system
+ * @tracing_dir: The directory that contains the events
+ * @tep: Allocated tep handler which will be filled
+ * @parsing_failures: return number of failures while parsing the event files
+ *
+ * Returns whether the operation succeeded
+ */
+int tracecmd_fill_local_events(const char *tracing_dir,
+			       struct tep_handle *tep, int *parsing_failures)
+{
+	return tracecmd_fill_local_events_system(tracing_dir, tep,
+						 NULL, parsing_failures);
+}
+
 /**
  * tracecmd_local_plugins - returns an array of available tracer plugins
  * @tracing_dir: The directory that contains the tracing directory
-- 
2.23.0