Dear Community,
> This code provides 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 is only 1 sec the original time is not
> restored and further tests are executed with this bias.
>
> It is important to note that adjtime() adjusts the system time with
> small ammounts in each second (it is in fact a wrapper on
> clock_adjtime with modes = ADJ_OFFSET_SINGLESHOT. In other words some
> seconds (may be a random value) needs to elapse until the required
> time offset is added to the clock. It may take considerable time (in
> minutes) to adjust clock by e.g. 1 second.
>
> To handle that the struct timeval odelta is passed to adjtime (NULL,
> &odelta) to get information of the still required delta to be added
> to clock. This is done in loop until its members are equal to 0.
>
> As a reference - CLOCK_MONOTONIC is used to check if CLOCK_REALTIME
> has been adjusted. The difference between them is measured.
Feedback more than welcome. Are there any comments regarding this patch?
> ---
> sysdeps/unix/sysv/linux/Makefile | 2 +-
> sysdeps/unix/sysv/linux/tst-adjtime.c | 82
> +++++++++++++++++++++++++++ 2 files changed, 83 insertions(+), 1
> deletion(-) create mode 100644 sysdeps/unix/sysv/linux/tst-adjtime.c
>
> diff --git a/sysdeps/unix/sysv/linux/Makefile
> b/sysdeps/unix/sysv/linux/Makefile index 6a45ac820a..25d2f05183 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -113,7 +113,7 @@ tests += tst-clone tst-clone2 tst-clone3
> tst-fanotify tst-personality \ tst-tgkill tst-sysvsem-linux
> tst-sysvmsg-linux tst-sysvshm-linux \ tst-timerfd tst-ppoll
> tst-futimens tst-utime tst-utimes \ tst-clock_adjtime tst-adjtimex
> tst-ntp_adjtime tst-futimes \
> - tst-lutimes tst-ntp_gettime tst-ntp_gettimex
> + tst-lutimes tst-ntp_gettime tst-ntp_gettimex tst-adjtime
> tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
> tests-time64 += \
> tst-futimes-time64\
> diff --git a/sysdeps/unix/sysv/linux/tst-adjtime.c
> b/sysdeps/unix/sysv/linux/tst-adjtime.c new file mode 100644
> index 0000000000..b381963be8
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-adjtime.c
> @@ -0,0 +1,82 @@
> +/* Test for 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
> + . */
> +
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +#define TIMEOUT (60*10)
> +#define ADJTIME_LOOP_SLEEP 10000
> +
> +static int
> +do_test (void)
> +{
> + struct timespec tv_then, tv_now, tv_then_m, tv_now_m;
> + struct timeval delta, odelta;
> + int ret;
> +
> + /* Check if altering target time is allowed. */
> + if (getenv (SETTIME_ENV_NAME) == NULL)
> + FAIL_UNSUPPORTED ("adjtime is executed only when "\
> + SETTIME_ENV_NAME" is set\n");
> +
> + tv_then = xclock_now (CLOCK_REALTIME);
> + tv_then_m = xclock_now (CLOCK_MONOTONIC);
> +
> + /* Setup time value to adjust - 1 sec. */
> + delta.tv_sec = 1;
> + delta.tv_usec = 0;
> +
> + ret = adjtime (&delta, NULL);
> + if (ret == -1)
> + FAIL_EXIT1 ("adjtime failed: %m\n");
> +
> + /* As adjtime adjust clock time gradually by some small percentage
> + of delta in each second one needs to check if this process has
> + been finished. */
> + do {
> + ret = adjtime (NULL, &odelta);
> + if (ret == -1)
> + FAIL_EXIT1 ("adjtime failed: %m\n");
> +
> + ret = usleep (ADJTIME_LOOP_SLEEP);
> + if (ret != 0)
> + FAIL_EXIT1 ("usleep failed: %m\n");
> +
> + } while ( ! (odelta.tv_sec == 0 && odelta.tv_usec == 0));
> +
> + tv_now = xclock_now (CLOCK_REALTIME);
> + tv_now_m = xclock_now (CLOCK_MONOTONIC);
> +
> + /* Check if adjtime adjusted the system time. */
> + struct timespec r = timespec_sub (tv_now, tv_then);
> + struct timespec r_m = timespec_sub (tv_now_m, tv_then_m);
> +
> + struct timespec r_adjtime = timespec_sub (r, r_m);
> +
> + TEST_COMPARE (support_timespec_check_in_range
> + ((struct timespec) { 1, 0 }, r_adjtime, 0.9, 1.1),
> 1); +
> + return 0;
> +}
> +
> +#include
Best regards,
Lukasz Majewski
--
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