[PATCHv4 23/28] selftest/timens: Add a test for clock_nanosleep()

[Dmitry Safonov <dima@arista.com>]

From: Andrei Vagin <avagin@gmail.com>

Check that clock_nanosleep() takes into account clock offsets.

Signed-off-by: Andrei Vagin <avagin@gmail.com>
Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 tools/testing/selftests/timens/.gitignore     |   1 +
 tools/testing/selftests/timens/Makefile       |   2 +-
 .../selftests/timens/clock_nanosleep.c        | 100 ++++++++++++++++++
 3 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/timens/clock_nanosleep.c

diff --git a/tools/testing/selftests/timens/.gitignore b/tools/testing/selftests/timens/.gitignore
index b609f6ee9fb9..9b6c8ddac2c8 100644
--- a/tools/testing/selftests/timens/.gitignore
+++ b/tools/testing/selftests/timens/.gitignore
@@ -1,2 +1,3 @@
+clock_nanosleep
 timens
 timerfd
diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
index 66b90cd28e5c..76a1dc891184 100644
--- a/tools/testing/selftests/timens/Makefile
+++ b/tools/testing/selftests/timens/Makefile
@@ -1,4 +1,4 @@
-TEST_GEN_PROGS := timens timerfd
+TEST_GEN_PROGS := timens timerfd clock_nanosleep
 
 CFLAGS := -Wall -Werror
 
diff --git a/tools/testing/selftests/timens/clock_nanosleep.c b/tools/testing/selftests/timens/clock_nanosleep.c
new file mode 100644
index 000000000000..dfd4e3429c75
--- /dev/null
+++ b/tools/testing/selftests/timens/clock_nanosleep.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <sched.h>
+
+#include <sys/timerfd.h>
+#include <sys/syscall.h>
+#include <time.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include "log.h"
+#include "timens.h"
+
+static long long get_elapsed_time(int clockid, struct timespec *start)
+{
+	struct timespec curr;
+	long long secs, nsecs;
+
+	if (clock_gettime(clockid, &curr) == -1)
+		return pr_perror("clock_gettime");
+
+	secs = curr.tv_sec - start->tv_sec;
+	nsecs = curr.tv_nsec - start->tv_nsec;
+	if (nsecs < 0) {
+		secs--;
+		nsecs += 1000000000;
+	}
+	if (nsecs > 1000000000) {
+		secs++;
+		nsecs -= 1000000000;
+	}
+	return secs * 1000 + nsecs / 1000000;
+}
+
+int run_test(int clockid)
+{
+	long long elapsed;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		struct timespec now = {};
+		struct timespec start;
+
+		if (clock_gettime(clockid, &start) == -1)
+			return pr_perror("clock_gettime");
+
+
+		if (i == 1) {
+			now.tv_sec = start.tv_sec;
+			now.tv_nsec = start.tv_nsec;
+		}
+
+		now.tv_sec += 2;
+		clock_nanosleep(clockid, i ? TIMER_ABSTIME : 0, &now, NULL);
+
+		elapsed = get_elapsed_time(clockid, &start);
+		if (elapsed < 1900 || elapsed > 2100) {
+			pr_fail("clockid: %d abs: %d elapsed: %lld\n",
+				clockid, i, elapsed);
+			return 1;
+		}
+		ksft_test_result_pass("clockid: %d abs:%d\n", clockid, i);
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret, nsfd;
+
+	nscheck();
+
+	if (unshare(CLONE_NEWTIME))
+		return pr_perror("unshare");
+
+	if (_settime(CLOCK_MONOTONIC, 7 * 24 * 3600))
+		return 1;
+	if (_settime(CLOCK_BOOTTIME, 9 * 24 * 3600))
+		return 1;
+
+	nsfd = open("/proc/self/ns/time_for_children", O_RDONLY);
+	if (nsfd < 0)
+		return pr_perror("Unable to open timens_for_children");
+
+	if (setns(nsfd, CLONE_NEWTIME))
+		return pr_perror("Unable to set timens");
+
+	ret = 0;
+	ret |= run_test(CLOCK_MONOTONIC);
+	ret |= run_test(CLOCK_BOOTTIME_ALARM);
+
+	if (ret)
+		ksft_exit_fail();
+	ksft_exit_pass();
+	return ret;
+}
+
-- 
2.22.0