A new API is added to tracefs library:
tracefs_get_clock()
It reads the trace_clock file from the ftrace file system, parses it
and returns a string with the current trace clock. The returned string
must be freed by free().
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
include/tracefs/tracefs.h | 2 ++
lib/tracefs/tracefs-instance.c | 35 ++++++++++++++++++++++++++++++++++
tracecmd/trace-stat.c | 29 +++++++---------------------
utest/tracefs-utest.c | 30 ++++++++++++++++++++++++++++-
4 files changed, 73 insertions(+), 23 deletions(-)
diff --git a/include/tracefs/tracefs.h b/include/tracefs/tracefs.h
index e796462a..07269cee 100644
--- a/include/tracefs/tracefs.h
+++ b/include/tracefs/tracefs.h
@@ -57,4 +57,6 @@ struct tep_handle *tracefs_local_events_system(const char *tracing_dir,
int tracefs_fill_local_events(const char *tracing_dir,
struct tep_handle *tep, int *parsing_failures);
+char *tracefs_get_clock(struct tracefs_instance *instance);
+
#endif /* _TRACE_FS_H */
diff --git a/lib/tracefs/tracefs-instance.c b/lib/tracefs/tracefs-instance.c
index 5ff313c7..6158804c 100644
--- a/lib/tracefs/tracefs-instance.c
+++ b/lib/tracefs/tracefs-instance.c
@@ -394,3 +394,38 @@ out:
tracefs_put_tracing_file(path);
return fret;
}
+
+/**
+ * tracefs_get_clock - Get the current trace clock
+ * @instance: ftrace instance, can be NULL for the top instance
+ *
+ * Returns the current trace clock of the given instance, or NULL in
+ * case of an error.
+ * The return string must be freed by free()
+ */
+char *tracefs_get_clock(struct tracefs_instance *instance)
+{
+ char *all_clocks = NULL;
+ char *ret = NULL;
+ int bytes = 0;
+ char *clock;
+ char *cont;
+
+ all_clocks = tracefs_instance_file_read(instance, "trace_clock", &bytes);
+ if (!all_clocks || !bytes)
+ goto out;
+
+ clock = strstr(all_clocks, "[");
+ if (!clock)
+ goto out;
+ clock++;
+ cont = strstr(clock, "]");
+ if (!cont)
+ goto out;
+ *cont = '\0';
+
+ ret = strdup(clock);
+out:
+ free(all_clocks);
+ return ret;
+}
diff --git a/tracecmd/trace-stat.c b/tracecmd/trace-stat.c
index e6678eab..9b61a14f 100644
--- a/tracecmd/trace-stat.c
+++ b/tracecmd/trace-stat.c
@@ -710,33 +710,18 @@ static void report_buffers(struct buffer_instance *instance)
static void report_clock(struct buffer_instance *instance)
{
- char *str;
- char *cont;
char *clock;
- str = get_instance_file_content(instance, "trace_clock");
- if (!str)
- return;
-
- clock = strstr(str, "[");
- if (!clock)
- goto out;
- clock++;
-
- cont = strstr(clock, "]");
- if (!cont) /* should never happen */
- goto out;
-
- *cont = '\0';
+ if (instance)
+ clock = tracefs_get_clock(instance->tracefs);
+ else
+ clock = tracefs_get_clock(NULL);
/* Default clock is "local", only show others */
- if (strcmp(clock, "local") == 0)
- goto out;
+ if (clock && !strcmp(clock, "local") == 0)
+ printf("\nClock: %s\n", clock);
- printf("\nClock: %s\n", clock);
-
- out:
- free(str);
+ free(clock);
}
static void report_cpumask(struct buffer_instance *instance)
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 7e9fe738..798fedb8 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -511,6 +511,33 @@ static void test_instances_walk(void)
}
}
+static void current_clock_check(const char *clock)
+{
+ int size = 0;
+ char *clocks;
+ char *str;
+
+ clocks = tracefs_instance_file_read(test_instance, "trace_clock", &size);
+ CU_TEST(clocks != NULL);
+ CU_TEST(size > strlen(clock));
+ str = strstr(clocks, clock);
+ CU_TEST(str != NULL);
+ CU_TEST(str != clocks);
+ CU_TEST(*(str - 1) == '[');
+ CU_TEST(*(str + strlen(clock)) == ']');
+ free(clocks);
+}
+
+static void test_get_clock(void)
+{
+ const char *clock;
+
+ clock = tracefs_get_clock(test_instance);
+ CU_TEST(clock != NULL);
+ current_clock_check(clock);
+ free((char *)clock);
+}
+
static int test_suite_destroy(void)
{
tracefs_instance_destroy(test_instance);
@@ -556,5 +583,6 @@ void test_tracefs_lib(void)
test_local_events);
CU_add_test(suite, "tracefs_instances_walk API",
test_instances_walk);
-
+ CU_add_test(suite, "tracefs_get_clock API",
+ test_get_clock);
}
--
2.28.0
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