[PATCH 0/2] Documentation and unit tests for new trace marker APIs

[PATCH 0/2] Documentation and unit tests for new trace marker APIs

[Tzvetomir Stoyanov (VMware)]

Documentation and unit tests for new trace marker APIs

Tzvetomir Stoyanov (VMware) (2):
  libtracefs: Document marker APIs
  libtracefs: Unit test for trace marker APIs

 Documentation/libtracefs-marker.txt | 127 ++++++++++++++++++++++++++++
 utest/tracefs-utest.c               |  91 ++++++++++++++++++++
 2 files changed, 218 insertions(+)
 create mode 100644 Documentation/libtracefs-marker.txt

-- 
2.30.2

[PATCH 1/2] libtracefs: Document marker APIs

[Tzvetomir Stoyanov (VMware)]

Added man pages describing these functions:
 tracefs_marker_init()
 tracefs_marker_print()
 tracefs_marker_vprint()
 tracefs_marker_write()
 tracefs_marker_close()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-marker.txt | 127 ++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 Documentation/libtracefs-marker.txt

diff --git a/Documentation/libtracefs-marker.txt b/Documentation/libtracefs-marker.txt
new file mode 100644
index 0000000..e2673d9
--- /dev/null
+++ b/Documentation/libtracefs-marker.txt
@@ -0,0 +1,127 @@
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_marker_init, tracefs_marker_close, tracefs_marker_print, tracefs_marker_vprint, tracefs_marker_write -
+Open, close and write data in the frace marker file.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+int *tracefs_marker_init*(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_marker_print*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, _..._);
+int *tracefs_marker_vprint*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, va_list _ap_);
+int *tracefs_marker_write*(struct tracefs_instance pass:[*]_instance_, void pass:[*]_data_, int _len_);
+void *tracefs_marker_close*(struct tracefs_instance pass:[*]_instance_);
+
+--
+
+DESCRIPTION
+-----------
+Set of functions to work with ftrace maker. See Documentation/trace/ftrace.rst from the Linux
+kernel tree for more information about ftrace marker functionality. All these APIs have _instance_
+as a first argument. If NULL is passed as _instance_, the top trace instance is used.
+
+The _tracefs_marker_init()_ function initializes the library for working with ftrace marker of
+the selected _instance_. It is not mandatory to call this API before working with the marker, any
+of the marker APIs will call it automatically, if the library is not yet initialized to work with
+the marker form given instance. But calling _tracefs_marker_init()_ in advance will speed up
+the other marker APIs.
+
+The _tracefs_marker_print()_ function writes a formatted string in the trace marker of the selected
+_instance_. The _fmt_ argument is a string in printf format, followed by variable arguments _..._.
+
+The _tracefs_marker_vprint()_ function writes a formatted string in the trace marker of the selected
+_instance_. The _fmt_ argument is a string in printf format, followed by list _ap_ of arguments.
+
+The _tracefs_marker_write()_ function writes a binary data in the trace marker of the selected
+_instance_. The _data_ points to the data with length _len_, that is going to be written in
+the trace marker.
+
+The _tracefs_marker_close()_ function closes the ftrace marker of the selected instance.
+
+RETURN VALUE
+------------
+The _tracefs_marker_init()_, _tracefs_marker_print()_, _tracefs_marker_vprint()_ and
+_tracefs_marker_write()_ functions return 0 if the operation is successful, or -1 in case of an error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <tracefs.h>
+
+if (tracefs_marker_init(NULL) < 0) {
+ /* Failed to initialize the library with the ftrace marker of the top trace instance */
+}
+
+void foo_print(char *format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	if (tracefs_marker_vprint(NULL, format, ap) < 0) {
+		/* Failed to print in the trace marker */
+	}
+	va_end(ap);
+}
+
+void foo_print_string(char *message)
+{
+	if (tracefs_marker_print(NULL, "Message from user space: %s", message) < 0) {
+		/* Failed to print in the trace marker */
+	}
+}
+
+unsigned int data = 0xdeadbeef;
+
+	if (tracefs_marker_write(NULL, &data, sizeof(data)) < 0) {
+		/* Failed to write in the trace marker */
+	}
+
+
+tracefs_marker_close();
+--
+FILES
+-----
+[verse]
+--
+*tracefs.h*
+	Header file to include in order to have access to the library APIs.
+*-ltracefs*
+	Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtracefs(3)_,
+_libtraceevent(3)_,
+_trace-cmd(1)_,
+Documentation/trace/ftrace.rst from the Linux kernel tree
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@goodmis.org>
+*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
+--
+REPORTING BUGS
+--------------
+Report bugs to  <linux-trace-devel@vger.kernel.org>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
+
+COPYING
+-------
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
-- 
2.30.2

[PATCH 2/2] libtracefs: Unit test for trace marker APIs

[Tzvetomir Stoyanov (VMware)]

Added unit tests for these APIs:
 tracefs_marker_init()
 tracefs_marker_print()
 tracefs_marker_vprint()
 tracefs_marker_write()
 tracefs_marker_close()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 utest/tracefs-utest.c | 91 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)

diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index ed2693b..bad4348 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -169,6 +169,95 @@ static const char *get_rand_str(void)
 	return str;
 }
 
+struct marker_find {
+	int len;
+	int count;
+	void *data;
+};
+
+static int test_marker_callback(struct tep_event *event, struct tep_record *record,
+				int cpu, void *context)
+{
+	struct marker_find *walk = context;
+	struct tep_format_field *field;
+
+	if (!walk)
+		return -1;
+	if (record->size < walk->len)
+		return 0;
+
+	field = tep_find_field(event, "buf");
+	if (field && memcmp(walk->data, record->data + field->offset, walk->len) == 0)
+		walk->count++;
+
+	return 0;
+}
+
+static bool find_test_marker(struct tracefs_instance *instance, void *data, int len, int expected)
+{
+	int ret;
+	struct marker_find walk;
+
+	walk.data = data;
+	walk.len = len;
+	walk.count = 0;
+	ret = tracefs_iterate_raw_events(test_tep, instance, NULL, 0,
+					 test_marker_callback, &walk);
+	CU_TEST(ret == 0);
+
+	return walk.count == expected;
+}
+
+static int marker_vprint(struct tracefs_instance *instance, char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, fmt);
+	ret = tracefs_marker_vprint(instance, fmt, ap);
+	va_end(ap);
+
+	return ret;
+}
+
+#define MARKERS_WRITE_COUNT	100
+static void test_instance_ftrace_marker(struct tracefs_instance *instance)
+{
+	const char *string = get_rand_str();
+	unsigned int data = 0xdeadbeef;
+	char *str;
+	int i;
+
+	CU_TEST(tracefs_marker_init(instance) == 0);
+	tracefs_marker_close(instance);
+
+	for (i = 0; i < MARKERS_WRITE_COUNT; i++) {
+		CU_TEST(tracefs_marker_write(instance, &data, sizeof(data)) == 0);
+	}
+	CU_TEST(find_test_marker(instance, &data, sizeof(data), MARKERS_WRITE_COUNT));
+
+	for (i = 0; i < MARKERS_WRITE_COUNT; i++) {
+		CU_TEST(tracefs_marker_print(instance, "Test marker: %s 0x%X", string, data) == 0);
+	}
+	asprintf(&str, "Test marker: %s 0x%X", string, data);
+	CU_TEST(find_test_marker(instance, str, strlen(str) + 1, MARKERS_WRITE_COUNT));
+	free(str);
+
+	for (i = 0; i < MARKERS_WRITE_COUNT; i++) {
+		CU_TEST(marker_vprint(instance, "Test marker V: %s 0x%X", string, data) == 0);
+	}
+	asprintf(&str, "Test marker V: %s 0x%X", string, data);
+	CU_TEST(find_test_marker(instance, str, strlen(str) + 1, MARKERS_WRITE_COUNT));
+	free(str);
+
+	tracefs_marker_close(instance);
+}
+
+static void test_ftrace_marker(void)
+{
+	test_instance_ftrace_marker(test_instance);
+}
+
 static void test_trace_file(void)
 {
 	const char *tmp = get_rand_str();
@@ -1075,4 +1164,6 @@ void test_tracefs_lib(void)
 		    test_tracing_options);
 	CU_add_test(suite, "custom system directory",
 		    test_custom_trace_dir);
+	CU_add_test(suite, "ftrace marker",
+		    test_ftrace_marker);
 }
-- 
2.30.2