Re: [PATCH] linux-user: Remove pointless NULL check in clock_adjtime handling

[Peter Maydell <peter.maydell@linaro.org>]

Laurent, ping? This patch has been reviewed.

thanks
-- PMM

On Fri, 23 Jun 2023 at 15:44, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
> the address of the local variable htx.  This means it can never be
> NULL, but later in the code we check it for NULL anyway.  Coverity
> complains about this (CID 1507683) because the NULL check comes after
> a call to clock_adjtime() that assumes it is non-NULL.
>
> Since phtx is always &htx, and is used only in three places, it's not
> really necessary.  Remove it, bringing the code structure in to line
> with that for TARGET_NR_clock_adjtime64, which already uses a simple
> '&htx' when it wants a pointer to 'htx'.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  linux-user/syscall.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index f2cb101d83c..7b2f9f7340e 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -10935,16 +10935,14 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
>  #if defined(TARGET_NR_clock_adjtime) && defined(CONFIG_CLOCK_ADJTIME)
>      case TARGET_NR_clock_adjtime:
>          {
> -            struct timex htx, *phtx = &htx;
> +            struct timex htx;
>
> -            if (target_to_host_timex(phtx, arg2) != 0) {
> +            if (target_to_host_timex(&htx, arg2) != 0) {
>                  return -TARGET_EFAULT;
>              }
> -            ret = get_errno(clock_adjtime(arg1, phtx));
> -            if (!is_error(ret) && phtx) {
> -                if (host_to_target_timex(arg2, phtx) != 0) {
> -                    return -TARGET_EFAULT;
> -                }
> +            ret = get_errno(clock_adjtime(arg1, &htx));
> +            if (!is_error(ret) && host_to_target_timex(arg2, &htx)) {
> +                return -TARGET_EFAULT;
>              }
>          }
>          return ret;
> --