tracefs_tracer_set - set the tracer
tracefs_tracer_clear - clear the tracer
Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Sameeruddin shaik <sameeross1994@xxxxxxxxx>
diff --git a/include/tracefs.h b/include/tracefs.h
index 55ee867..e261b8a 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -173,4 +173,23 @@ int tracefs_function_filter(struct tracefs_instance *instance, const char *filte
int tracefs_function_notrace(struct tracefs_instance *instance, const char *filter,
const char *module, unsigned int flags);
+enum tracefs_tracers {
+ TRACEFS_TRACER_NOP = 0,
+ TRACEFS_TRACER_FUNCTION,
+ TRACEFS_TRACER_FUNCTION_GRAPH,
+ TRACEFS_TRACER_IRQSOFF,
+ TRACEFS_TRACER_PREEMPTOFF,
+ TRACEFS_TRACER_PREEMPTIRQSOFF,
+ TRACEFS_TRACER_WAKEUP,
+ TRACEFS_TRACER_WAKEUP_RT,
+ TRACEFS_TRACER_WAKEUP_DL,
+ TRACEFS_TRACER_MMIOTRACE,
+ TRACEFS_TRACER_HWLAT,
+ TRACEFS_TRACER_BRANCH,
+ TRACEFS_TRACER_BLOCK,
+};
+
+int tracefs_tracer_set(struct tracefs_instance *instance, enum tracefs_tracers tracer);
+
+int tracefs_tracer_clear(struct tracefs_instance *instance);
#endif /* _TRACE_FS_H */
diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c
index 6ef17f6..f535231 100644
--- a/src/tracefs-tools.c
+++ b/src/tracefs-tools.c
@@ -25,6 +25,30 @@ __hidden pthread_mutex_t toplevel_lock = PTHREAD_MUTEX_INITIALIZER;
#define TRACE_FILTER "set_ftrace_filter"
#define TRACE_NOTRACE "set_ftrace_notrace"
#define TRACE_FILTER_LIST "available_filter_functions"
+#define CUR_TRACER "current_tracer"
+
+#define TRACERS \
+ C(NOP, "nop"), \
+ C(FUNCTION, "function"), \
+ C(FUNCTION_GRAPH, "function_graph"), \
+ C(IRQSOFF, "irqsoff"), \
+ C(PREEMPTOFF, "preemptoff"), \
+ C(PREEMPTIRQSOFF, "preemptirqsoff"), \
+ C(WAKEUP, "wakeup"), \
+ C(WAKEUP_RT, "wakeup_rt"), \
+ C(WAKEUP_DL, "wakeup_dl"), \
+ C(MMIOTRACE, "mmiotrace"), \
+ C(HWLAT, "hwlat"), \
+ C(BRANCH, "branch"), \
+ C(BLOCK, "block")
+
+#undef C
+#define C(a, b) b
+const char *tracers[] = { TRACERS };
+
+#undef C
+#define C(a, b) TRACEFS_TRACER_##a
+const int tracer_enums[] = { TRACERS };
/* File descriptor for Top level set_ftrace_filter */
static int ftrace_filter_fd = -1;
@@ -910,3 +934,68 @@ int tracefs_function_notrace(struct tracefs_instance *instance, const char *filt
tracefs_put_tracing_file(filter_path);
return ret;
}
+
+int write_tracer(int fd, const char *tracer)
+{
+ int ret;
+
+ ret = write(fd, tracer, strlen(tracer));
+ if (ret < strlen(tracer))
+ return -1;
+ return ret;
+}
+
+/**
+ * tracefs_set_tracer - function to set the tracer
+ * @instance: ftrace instance, can be NULL for top tracing instance
+ * @tracer: Tracer that has to be set, which can be integer from 0 - 12
+ * or enum value
+ */
+
+int tracefs_tracer_set(struct tracefs_instance *instance, enum tracefs_tracers tracer)
+{
+ char *tracer_path = NULL;
+ const char *t = NULL;
+ int ret = -1;
+ int fd = -1;
+ int i;
+
+ tracer_path = tracefs_instance_get_file(instance, CUR_TRACER);
+ if (!tracer_path)
+ return -1;
+
+ fd = open(tracer_path, O_WRONLY);
+ if (fd < 0) {
+ errno = -ENOENT;
+ goto out;
+ }
+
+ if (tracer < 0 || tracer > ARRAY_SIZE(tracers)) {
+ errno = -ENODEV;
+ goto out;
+ }
+ if (tracer == tracer_enums[tracer])
+ t = tracers[tracer];
+ else {
+ for (i = 0; i < ARRAY_SIZE(tracer_enums); i++) {
+ if (tracer == tracer_enums[i]) {
+ t = tracers[i];
+ break;
+ }
+ }
+ }
+ if (!t) {
+ errno = -EINVAL;
+ goto out;
+ }
+ ret = write_tracer(fd, t);
+ out:
+ tracefs_put_tracing_file(tracer_path);
+ close(fd);
+ return ret;
+}
+
+int tracefs_tracer_clear(struct tracefs_instance *instance)
+{
+ return tracefs_tracer_set(instance, TRACEFS_TRACER_NOP);
+}
--
2.7.4
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