tst: Add test for clock_adjtime

This code privides test to check if time on target machine is properly
adjusted.
The time is altered only when cross-test-ssh.sh is executed with
--allow-time-setting flag.
As the delta added to CLOCK_REALTIME is only 1 sec the original time is
not restored and further tests are executed with this bias.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

2 files changed, 59 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 51e28b9..d0beb2f 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -107,7 +107,8 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
 	 tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
 	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
-	 tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes
+	 tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes \
+	 tst-clock_adjtime
 tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
 
 CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables
diff --git a/sysdeps/unix/sysv/linux/tst-clock_adjtime.c b/sysdeps/unix/sysv/linux/tst-clock_adjtime.c
new file mode 100644
index 0000000..6b9bb99
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-clock_adjtime.c
@@ -0,0 +1,57 @@
+/* Test for clock_adjtime
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <time.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <support/check.h>
+#include <support/timespec.h>
+
+static int
+do_test (void)
+{
+  struct timespec tv_then, tv_now;
+  struct timex delta;
+
+  /* Check if altering target time is allowed.  */
+  if (getenv (SETTIME_ENV_NAME) == NULL)
+    FAIL_UNSUPPORTED ("clock_adjtime is executed only when "\
+                      SETTIME_ENV_NAME" is set\n");
+
+  tv_then = xclock_now (CLOCK_REALTIME);
+
+  /* Setup time value to adjust - 1 sec. */
+  delta.time.tv_sec = 1;
+  delta.time.tv_usec = 0;
+  delta.modes = ADJ_SETOFFSET;
+
+  int ret = clock_adjtime (CLOCK_REALTIME, &delta);
+  if (ret == -1)
+    FAIL_EXIT1 ("clock_adjtime failed: %m\n");
+
+  tv_now = xclock_now (CLOCK_REALTIME);
+
+  /* Check if clock_adjtime adjusted the system time.  */
+  struct timespec r = timespec_sub (tv_now, tv_then);
+  TEST_COMPARE (support_timespec_check_in_range
+                ((struct timespec) { 1, 0 }, r, 0.9, 1.1), 1);
+
+  return 0;
+}
+
+#include <support/test-driver.c>