The logic for finding all configured ftrace instances is encapuslated in
a new tracefs_instances_walk() API. A user specified callback is
called for each ftrace instance in the system, excpet for the top level
one.
The implementation of "trace-cmd stat" is modified to use the new API.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
include/tracefs/tracefs.h | 1 +
lib/tracefs/include/tracefs-local.h | 1 +
lib/tracefs/tracefs-events.c | 14 ++++----
lib/tracefs/tracefs-instance.c | 52 +++++++++++++++++++++++++++++
tracecmd/trace-stat.c | 52 ++++++++---------------------
utest/tracefs-utest.c | 51 ++++++++++++++++++++++++++++
6 files changed, 125 insertions(+), 46 deletions(-)
diff --git a/include/tracefs/tracefs.h b/include/tracefs/tracefs.h
index 63f1944a..e796462a 100644
--- a/include/tracefs/tracefs.h
+++ b/include/tracefs/tracefs.h
@@ -32,6 +32,7 @@ int tracefs_instance_file_write(struct tracefs_instance *instance,
const char *file, const char *str);
char *tracefs_instance_file_read(struct tracefs_instance *instance,
char *file, int *psize);
+int tracefs_instances_walk(int (*callback)(const char *, void *), void *context);
bool tracefs_instance_exists(const char *name);
bool tracefs_file_exists(struct tracefs_instance *instance, char *name);
diff --git a/lib/tracefs/include/tracefs-local.h b/lib/tracefs/include/tracefs-local.h
index fe327a0f..08b67fa9 100644
--- a/lib/tracefs/include/tracefs-local.h
+++ b/lib/tracefs/include/tracefs-local.h
@@ -9,5 +9,6 @@
/* Can be overridden */
void warning(const char *fmt, ...);
int str_read_file(const char *file, char **buffer);
+char *trace_append_file(const char *dir, const char *name);
#endif /* _TRACE_FS_LOCAL_H */
diff --git a/lib/tracefs/tracefs-events.c b/lib/tracefs/tracefs-events.c
index 19f98058..60797748 100644
--- a/lib/tracefs/tracefs-events.c
+++ b/lib/tracefs/tracefs-events.c
@@ -210,7 +210,7 @@ static char **add_list_string(char **list, const char *name, int len)
return list;
}
-static char *append_file(const char *dir, const char *name)
+char *trace_append_file(const char *dir, const char *name)
{
char *file;
int ret;
@@ -265,7 +265,7 @@ const char **tracefs_event_systems(const char *tracing_dir)
if (!tracing_dir)
return NULL;
- events_dir = append_file(tracing_dir, "events");
+ events_dir = trace_append_file(tracing_dir, "events");
if (!events_dir)
return NULL;
@@ -290,14 +290,14 @@ const char **tracefs_event_systems(const char *tracing_dir)
strcmp(name, "..") == 0)
continue;
- sys = append_file(events_dir, name);
+ sys = trace_append_file(events_dir, name);
ret = stat(sys, &st);
if (ret < 0 || !S_ISDIR(st.st_mode)) {
free(sys);
continue;
}
- enable = append_file(sys, "enable");
+ enable = trace_append_file(sys, "enable");
ret = stat(enable, &st);
if (ret >= 0)
@@ -358,7 +358,7 @@ const char **tracefs_system_events(const char *tracing_dir, const char *system)
strcmp(name, "..") == 0)
continue;
- event = append_file(system_dir, name);
+ event = trace_append_file(system_dir, name);
ret = stat(event, &st);
if (ret < 0 || !S_ISDIR(st.st_mode)) {
free(event);
@@ -400,7 +400,7 @@ const char **tracefs_tracers(const char *tracing_dir)
if (!tracing_dir)
return NULL;
- available_tracers = append_file(tracing_dir, "available_tracers");
+ available_tracers = trace_append_file(tracing_dir, "available_tracers");
if (!available_tracers)
return NULL;
@@ -492,7 +492,7 @@ static int read_header(struct tep_handle *tep, const char *tracing_dir)
int len;
int ret = -1;
- header = append_file(tracing_dir, "events/header_page");
+ header = trace_append_file(tracing_dir, "events/header_page");
ret = stat(header, &st);
if (ret < 0)
diff --git a/lib/tracefs/tracefs-instance.c b/lib/tracefs/tracefs-instance.c
index 655c6d20..5ff313c7 100644
--- a/lib/tracefs/tracefs-instance.c
+++ b/lib/tracefs/tracefs-instance.c
@@ -13,6 +13,7 @@
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
+#include <dirent.h>
#include <linux/limits.h>
#include "tracefs.h"
#include "tracefs-local.h"
@@ -342,3 +343,54 @@ bool tracefs_dir_exists(struct tracefs_instance *instance, char *name)
{
return check_file_exists(instance, name, true);
}
+
+/**
+ * tracefs_instances_walk - Iterate through all ftrace instances in the system
+ * @callback: user callback, called for each instance. Instance name is passed
+ * as input parameter. If the @callback returns non-zero,
+ * the iteration stops.
+ * @context: user context, passed to the @callback.
+ *
+ * Returns -1 in case of an error, 0 otherwise.
+ */
+int tracefs_instances_walk(int (*callback)(const char *, void *), void *context)
+{
+ struct dirent *dent;
+ char *path = NULL;
+ DIR *dir = NULL;
+ struct stat st;
+ int fret = -1;
+ int ret;
+
+ path = tracefs_get_tracing_file("instances");
+ if (!path)
+ return -1;
+ ret = stat(path, &st);
+ if (ret < 0 || !S_ISDIR(st.st_mode))
+ goto out;
+
+ dir = opendir(path);
+ if (!dir)
+ goto out;
+ fret = 0;
+ while ((dent = readdir(dir))) {
+ char *instance;
+
+ if (strcmp(dent->d_name, ".") == 0 ||
+ strcmp(dent->d_name, "..") == 0)
+ continue;
+ instance = trace_append_file(path, dent->d_name);
+ ret = stat(instance, &st);
+ free(instance);
+ if (ret < 0 || !S_ISDIR(st.st_mode))
+ continue;
+ if (callback(dent->d_name, context))
+ break;
+ }
+
+out:
+ if (dir)
+ closedir(dir);
+ tracefs_put_tracing_file(path);
+ return fret;
+}
diff --git a/tracecmd/trace-stat.c b/tracecmd/trace-stat.c
index 5f79ff8a..e6678eab 100644
--- a/tracecmd/trace-stat.c
+++ b/tracecmd/trace-stat.c
@@ -7,7 +7,6 @@
#include <sys/stat.h>
#include <stdlib.h>
#include <stdio.h>
-#include <dirent.h>
#include <getopt.h>
#include <unistd.h>
#include <fcntl.h>
@@ -140,48 +139,23 @@ static void report_file(struct buffer_instance *instance,
free(str);
}
-static void report_instances(void)
+static int report_instance(const char *name, void *data)
{
- struct dirent *dent;
- bool first = true;
- char *path = NULL;
- DIR *dir = NULL;
- struct stat st;
- int ret;
-
- path = tracefs_get_tracing_file("instances");
- if (!path)
- return;
- ret = stat(path, &st);
- if (ret < 0 || !S_ISDIR(st.st_mode))
- goto out;
-
- dir = opendir(path);
- if (!dir)
- goto out;
-
- while ((dent = readdir(dir))) {
- char *instance;
+ bool *first = (bool *)data;
- if (strcmp(dent->d_name, ".") == 0 ||
- strcmp(dent->d_name, "..") == 0)
- continue;
- instance = append_file(path, dent->d_name);
- ret = stat(instance, &st);
- free(instance);
- if (ret < 0 || !S_ISDIR(st.st_mode))
- continue;
- if (first) {
- first = false;
- printf("\nInstances:\n");
- }
- printf(" %s\n", dent->d_name);
+ if (*first) {
+ *first = false;
+ printf("\nInstances:\n");
}
+ printf(" %s\n", name);
+ return 0;
+}
-out:
- if (dir)
- closedir(dir);
- tracefs_put_tracing_file(path);
+static void report_instances(void)
+{
+ bool first = true;
+
+ tracefs_instances_walk(report_instance, &first);
}
struct event_iter *trace_event_iter_alloc(const char *path)
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index e24fb38b..7e9fe738 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -463,6 +463,54 @@ static void test_local_events(void)
tracefs_list_free(systems);
}
+struct test_walk_instance {
+ struct tracefs_instance *instance;
+ bool found;
+};
+#define WALK_COUNT 10
+int test_instances_walk_cb(const char *name, void *data)
+{
+ struct test_walk_instance *instances = (struct test_walk_instance *)data;
+ int i;
+
+ CU_TEST(instances != NULL);
+ CU_TEST(name != NULL);
+
+ for (i = 0; i < WALK_COUNT; i++) {
+ if (!strcmp(name,
+ tracefs_instance_get_name(instances[i].instance))) {
+ instances[i].found = true;
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static void test_instances_walk(void)
+{
+ struct test_walk_instance instances[WALK_COUNT];
+ int i;
+
+ memset(instances, 0, WALK_COUNT * sizeof(struct test_walk_instance));
+ for (i = 0; i < WALK_COUNT; i++) {
+ CU_TEST(tracefs_instance_create(get_rand_str(), &(instances[i].instance)) >= 0);
+ }
+
+ CU_TEST(tracefs_instances_walk(test_instances_walk_cb, instances) == 0);
+ for (i = 0; i < WALK_COUNT; i++) {
+ CU_TEST(instances[i].found);
+ tracefs_instance_destroy(instances[i].instance);
+ instances[i].found = false;
+ }
+
+ CU_TEST(tracefs_instances_walk(test_instances_walk_cb, instances) == 0);
+ for (i = 0; i < WALK_COUNT; i++) {
+ CU_TEST(!instances[i].found);
+ tracefs_instance_free(instances[i].instance);
+ }
+}
+
static int test_suite_destroy(void)
{
tracefs_instance_destroy(test_instance);
@@ -506,4 +554,7 @@ void test_tracefs_lib(void)
test_tracers);
CU_add_test(suite, "tracefs_local events API",
test_local_events);
+ CU_add_test(suite, "tracefs_instances_walk API",
+ test_instances_walk);
+
}
--
2.28.0
|