Re: [PATCH v2 12/12] linux-user: fix clock_nanosleep()

[Laurent Vivier <laurent@vivier.eu>]

Le 22/07/2020 à 08:29, Alex Bennée a écrit :
> From: Laurent Vivier <laurent@vivier.eu>
> 
> If clock_nanosleep() encounters an error, it returns one of the positive
> error number.
> 
> If the call is interrupted by a signal handler, it fails with error EINTR
> and if "remain" is not NULL and "flags" is not TIMER_ABSTIME, it returns
> the remaining unslept time in "remain".
> 
> Update linux-user to not overwrite the "remain" structure if there is no
> error.
> 
> Found with "make check-tcg", linux-test fails on nanosleep test:
> 
>   TEST    linux-test on x86_64
> .../tests/tcg/multiarch/linux-test.c:242: nanosleep
> make[2]: *** [../Makefile.target:153: run-linux-test] Error 1
> make[1]: *** [.../tests/tcg/Makefile.qemu:76: run-guest-tests] Error 2
> make: *** [.../tests/Makefile.include:857: run-tcg-tests-x86_64-linux-user] Error 2
> 
> Reported-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> Message-Id: <20200721201754.2731479-1-laurent@vivier.eu>
> ---
>  linux-user/syscall.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 1211e759c26..caa7cd3cab9 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -11829,10 +11829,19 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>      {
>          struct timespec ts;
>          target_to_host_timespec(&ts, arg3);
> -        ret = get_errno(safe_clock_nanosleep(arg1, arg2,
> -                                             &ts, arg4 ? &ts : NULL));
> -        if (arg4)
> +        /*
> +         * clock_nanosleep() returns 0 or one of the *positive* error number.
> +         */
> +        ret = host_to_target_errno(safe_clock_nanosleep(arg1, arg2, &ts,
> +                                                        arg4 ? &ts : NULL));
> +        /*
> +         * if the call is interrupted by a signal handler, it fails
> +         * with error TARGET_EINTR and if arg4 is not NULL and arg2 is not
> +         * TIMER_ABSTIME, it returns the remaining unslept time in arg4.
> +         */
> +        if (ret == TARGET_EINTR && arg4 && arg2 != TIMER_ABSTIME) {
>              host_to_target_timespec(arg4, &ts);
> +        }
>  
>  #if defined(TARGET_PPC)
>          /* clock_nanosleep is odd in that it returns positive errno values.
> 

Wait a little before pushing that: I've made more tests and it seems to
break something in LTP. I have to analyze.

Thanks,
Laurent