[PATCH] linux: Allow adjtime with NULL argument [BZ #26833]

[Carlos Seo]

LGTM. Checked on aarch64-linux-gnu and powerpc64-linux-gnu.

On Mon, 2 Nov 2020 at 17:01, Adhemerval Zanella via Libc-alpha <
libc-alpha@sourceware.org> wrote:

> The adjtime interface allows return the amount of time remaining
> from any previous adjustment that has not yet been completed by
> passing a NULL as first argument.  This was introduced with y2038
> support 0308077e3a.
>
> Checked on i686-linux-gnu.
> ---
>  sysdeps/unix/sysv/linux/adjtime.c | 11 ++++++--
>  time/Makefile                     |  3 +-
>  time/tst-adjtime.c                | 46 +++++++++++++++++++++++++++++++
>  3 files changed, 56 insertions(+), 4 deletions(-)
>  create mode 100644 time/tst-adjtime.c
>
> diff --git a/sysdeps/unix/sysv/linux/adjtime.c
> b/sysdeps/unix/sysv/linux/adjtime.c
> index 3f9a4ea2eb..6d1d1b6af2 100644
> --- a/sysdeps/unix/sysv/linux/adjtime.c
> +++ b/sysdeps/unix/sysv/linux/adjtime.c
> @@ -68,11 +68,16 @@ libc_hidden_def (__adjtime64)
>  int
>  __adjtime (const struct timeval *itv, struct timeval *otv)
>  {
> -  struct __timeval64 itv64, otv64;
> +  struct __timeval64 itv64, *pitv64 = NULL;
> +  struct __timeval64 otv64;
>    int retval;
>
> -  itv64 = valid_timeval_to_timeval64 (*itv);
> -  retval = __adjtime64 (&itv64, otv != NULL ? &otv64 : NULL);
> +  if (itv != NULL)
> +    {
> +      itv64 = valid_timeval_to_timeval64 (*itv);
> +      pitv64 = &itv64;
> +    }
> +  retval = __adjtime64 (pitv64, otv != NULL ? &otv64 : NULL);
>    if (otv != NULL)
>      *otv = valid_timeval64_to_timeval (otv64);
>
> diff --git a/time/Makefile b/time/Makefile
> index 26aa835166..f27a75a115 100644
> --- a/time/Makefile
> +++ b/time/Makefile
> @@ -47,7 +47,8 @@ tests := test_time clocktest tst-posixtz tst-strptime
> tst_wcsftime \
>            tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r bug-mktime1
> \
>            tst-strptime3 bug-getdate1 tst-strptime-whitespace tst-ftime \
>            tst-tzname tst-y2039 bug-mktime4 tst-strftime2 tst-strftime3 \
> -          tst-clock tst-clock2 tst-clock_nanosleep tst-cpuclock1
> +          tst-clock tst-clock2 tst-clock_nanosleep tst-cpuclock1 \
> +          tst-adjtime
>
>  include ../Rules
>
> diff --git a/time/tst-adjtime.c b/time/tst-adjtime.c
> new file mode 100644
> index 0000000000..0c39a98523
> --- /dev/null
> +++ b/time/tst-adjtime.c
> @@ -0,0 +1,46 @@
> +/* Test program for adjtime function.
> +   Copyright (C) 2020 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 <sys/time.h>
> +#include <stdlib.h>
> +
> +#include <errno.h>
> +#include <support/check.h>
> +
> +
> +/* This tests is a regression one that just check the non-privileged
> +   interface provided by adjtime.  */
> +
> +static int
> +do_test (void)
> +{
> +  /* Check if the interface allows getting the amount of time remaining
> +     from any previous adjustment that has not yet been completed.  */
> +  struct timeval tv;
> +  int r = adjtime (NULL, &tv);
> +  if (r == -1)
> +    {
> +      if (errno == ENOSYS)
> +       FAIL_UNSUPPORTED ("adjtime unsupported");
> +      FAIL_EXIT1 ("adjtime (NULL, ...) failed: %m");
> +    }
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.25.1
>
>