[PATCH] selftests/timens: handle a case when alarm clocks are not supported

[Andrei Vagin <avagin@gmail.com>]

This can happen if a testing node doesn't have RTC (real time clock)
hardware or it doesn't support alarms.

Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
---
 tools/testing/selftests/timens/clock_nanosleep.c |  2 +-
 tools/testing/selftests/timens/timens.c          |  2 +-
 tools/testing/selftests/timens/timens.h          | 13 ++++++++++++-
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/timens/clock_nanosleep.c b/tools/testing/selftests/timens/clock_nanosleep.c
index 8e7b7c72ef65..72d41b955fb2 100644
--- a/tools/testing/selftests/timens/clock_nanosleep.c
+++ b/tools/testing/selftests/timens/clock_nanosleep.c
@@ -119,7 +119,7 @@ int main(int argc, char *argv[])
 
 	ksft_set_plan(4);
 
-	check_config_posix_timers();
+	check_supported_timers();
 
 	if (unshare_timens())
 		return 1;
diff --git a/tools/testing/selftests/timens/timens.c b/tools/testing/selftests/timens/timens.c
index 559d26e21ba0..07feebe8e53e 100644
--- a/tools/testing/selftests/timens/timens.c
+++ b/tools/testing/selftests/timens/timens.c
@@ -156,7 +156,7 @@ int main(int argc, char *argv[])
 
 	nscheck();
 
-	check_config_posix_timers();
+	check_supported_timers();
 
 	ksft_set_plan(ARRAY_SIZE(clocks) * 2);
 
diff --git a/tools/testing/selftests/timens/timens.h b/tools/testing/selftests/timens/timens.h
index e09e7e39bc52..d4fc52d47146 100644
--- a/tools/testing/selftests/timens/timens.h
+++ b/tools/testing/selftests/timens/timens.h
@@ -14,15 +14,26 @@
 #endif
 
 static int config_posix_timers = true;
+static int config_alarm_timers = true;
 
-static inline void check_config_posix_timers(void)
+static inline void check_supported_timers(void)
 {
+	struct timespec ts;
+
 	if (timer_create(-1, 0, 0) == -1 && errno == ENOSYS)
 		config_posix_timers = false;
+
+	if (clock_gettime(CLOCK_BOOTTIME_ALARM, &ts) == -1 && errno == EINVAL)
+		config_alarm_timers = false;
 }
 
 static inline bool check_skip(int clockid)
 {
+	if (!config_alarm_timers && clockid == CLOCK_BOOTTIME_ALARM) {
+		ksft_test_result_skip("CLOCK_BOOTTIME_ALARM isn't supported\n");
+		return true;
+	}
+
 	if (config_posix_timers)
 		return false;
 
-- 
2.24.1