From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Add the API of the following functions:
tracefs_event_enable()
tracefs_event_disable()
That takes a system string and an event string and enables the events that
match. Where a NULL system means (all systems) and a NULL event means all
events in the system.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
Changes since v1:
- free the regex of system and event if they are created.
include/tracefs.h | 3 +
src/tracefs-events.c | 149 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 152 insertions(+)
diff --git a/include/tracefs.h b/include/tracefs.h
index 551c37c..73ee42b 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -55,6 +55,9 @@ int tracefs_trace_off(struct tracefs_instance *instance);
int tracefs_trace_on_fd(int fd);
int tracefs_trace_off_fd(int fd);
+int tracefs_event_enable(struct tracefs_instance *instance, const char *system, const char *event);
+int tracefs_event_disable(struct tracefs_instance *instance, const char *system, const char *event);
+
/**
* tracefs_trace_on_get_fd - Get a file descriptor of "tracing_on" in given instance
* @instance: ftrace instance, can be NULL for the top instance
diff --git a/src/tracefs-events.c b/src/tracefs-events.c
index 2343fc1..55316c6 100644
--- a/src/tracefs-events.c
+++ b/src/tracefs-events.c
@@ -777,3 +777,152 @@ int tracefs_fill_local_events(const char *tracing_dir,
return fill_local_events_system(tracing_dir, tep,
NULL, parsing_failures);
}
+
+static bool match(const char *str, regex_t *re)
+{
+ return regexec(re, str, 0, NULL, 0) == 0;
+}
+
+static int enable_disable_event(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ bool enable)
+{
+ const char *str = enable ? "1" : "0";
+ char *system_event;
+ int ret;
+
+ ret = asprintf(&system_event, "events/%s/%s/enable", system, event);
+ if (ret < 0)
+ return ret;
+
+ ret = tracefs_instance_file_write(instance, system_event, str);
+ free(system_event);
+
+ return ret;
+}
+
+static int enable_disable_system(struct tracefs_instance *instance,
+ const char *system, bool enable)
+{
+ const char *str = enable ? "1" : "0";
+ char *system_path;
+ int ret;
+
+ ret = asprintf(&system_path, "events/%s/enable", system);
+ if (ret < 0)
+ return ret;
+
+ ret = tracefs_instance_file_write(instance, system_path, str);
+ free(system_path);
+
+ return ret;
+}
+
+static int enable_disable_all(struct tracefs_instance *instance,
+ bool enable)
+{
+ const char *str = enable ? "1" : "0";
+
+ return tracefs_instance_file_write(instance, "events/enable", str);
+}
+
+static int event_enable_disable(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ bool enable)
+{
+ regex_t system_re, event_re;
+ char **systems;
+ char **events = NULL;
+ int ret = -1;
+ int s, e;
+
+ /* Handle all events first */
+ if (!system && !event)
+ return enable_disable_all(instance, enable);
+
+ systems = tracefs_event_systems(NULL);
+ if (!systems)
+ goto out_free;
+
+ if (system) {
+ ret = regcomp(&system_re, system, REG_ICASE|REG_NOSUB);
+ if (ret < 0)
+ goto out_free;
+ }
+ if (event) {
+ ret = regcomp(&event_re, event, REG_ICASE|REG_NOSUB);
+ if (ret < 0) {
+ if (system)
+ regfree(&system_re);
+ goto out_free;
+ }
+ }
+
+ for (s = 0; systems[s]; s++) {
+ if (system && !match(systems[s], &system_re))
+ continue;
+
+ /* Check for the short cut first */
+ if (!event) {
+ ret = enable_disable_system(instance, systems[s], enable);
+ if (ret < 0)
+ break;
+ ret = 0;
+ continue;
+ }
+
+ events = tracefs_system_events(NULL, systems[s]);
+ if (!events)
+ continue; /* Error? */
+
+ for (e = 0; events[e]; e++) {
+ if (!match(events[e], &event_re))
+ continue;
+ ret = enable_disable_event(instance, systems[s],
+ events[e], enable);
+ if (ret < 0)
+ break;
+ ret = 0;
+ }
+ tracefs_list_free(events);
+ events = NULL;
+ }
+ if (system)
+ regfree(&system_re);
+ if (event)
+ regfree(&event_re);
+
+ out_free:
+ tracefs_list_free(systems);
+ tracefs_list_free(events);
+ return ret;
+}
+
+/**
+ * tracefs_event_enable - enable specified events
+ * @instance: ftrace instance, can be NULL for the top instance
+ * @system: A regex of a system (NULL to match all systems)
+ * @event: A regex of the event in the system (NULL to match all events)
+ *
+ * This will enable events that match the @system and @event.
+ * If both @system and @event are NULL, then it will enable all events.
+ * If @system is NULL, it will look at all systems for matching events
+ * to @event.
+ * If @event is NULL, then it will enable all events in the systems
+ * that match @system.
+ *
+ * Returns 0 on success, and -1 if it encountered an error,
+ * or if no events matched. If no events matched, then -1 is set
+ * but errno will not be.
+ */
+int tracefs_event_enable(struct tracefs_instance *instance,
+ const char *system, const char *event)
+{
+ return event_enable_disable(instance, system, event, true);
+}
+
+int tracefs_event_disable(struct tracefs_instance *instance,
+ const char *system, const char *event)
+{
+ return event_enable_disable(instance, system, event, false);
+}
--
2.29.2
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