Re: [PATCH v2 1/2] linux-user: Add support for two 'clock_nanosleep_time64()' and 'clock_adjtime64()'

[Laurent Vivier <laurent@vivier.eu>]

Le 27/07/2020 à 13:23, Filip Bozuta a écrit :
> This patch implements functionality for following time64 syscall:
> 
> *clock_nanosleep_time64()
> 
>     This is a year 2038 safe vairant of syscall:
>     int clock_nanosleep(clockid_t clockid, int flags,
>                         const struct timespec *request,
>                         struct timespec *remain)
>     --high-resolution sleep with specifiable clock--
>     man page: https://man7.org/linux/man-pages/man2/clock_nanosleep.2.html
> 
> *clock_adjtime64()
> 
>     This is a year 2038 safe variant of syscall:
>     int clock_adjtime(clockid_t clk_id, struct timex *buf)
>     --tune kernel clock--
>     man page: https://man7.org/linux/man-pages/man2/clock_adjtime.2.html
> 
> Implementation notes:
> 
>     Syscall 'clock_nanosleep_time64()' was implemented similarly
>     to syscall 'clock_nanosleep()' except that 'host_to_target_timespec64()'
>     and 'target_to_host_timespec64()' were used instead of the regular
>     'host_to_target_timespec()' and 'target_to_host_timespec()'.
> 
>     For 'clock_adjtime64()' a 64-bit target kernel version of 'struct timex'
>     was defined in 'syscall_defs.h': 'struct target__kernel_timex'.
>     This type was used to convert the values of 64-bit timex type between
>     host and target. For this purpose a 64-bit timex converting functions
>     'target_to_host_timex64()' and 'host_to_target_timex64()'. An existing
>     function 'copy_to_user_timeval64()' was used to convert the field
>     'time' which if of type 'struct timeval' from host to target.
>     Function 'copy_from_user_timveal64()' was added in this patch and
>     used to convert the 'time' field from target to host.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/syscall.c      | 139 +++++++++++++++++++++++++++++++++++++-
>  linux-user/syscall_defs.h |  31 +++++++++
>  2 files changed, 168 insertions(+), 2 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 05f03919ff..c1b36ea698 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -809,7 +809,8 @@ safe_syscall4(int, accept4, int, fd, struct sockaddr *, addr, socklen_t *, len,
>  safe_syscall2(int, nanosleep, const struct timespec *, req,
>                struct timespec *, rem)
>  #endif
> -#ifdef TARGET_NR_clock_nanosleep
> +#if defined(TARGET_NR_clock_nanosleep) || \
> +    defined(TARGET_NR_clock_nanosleep_time64)
>  safe_syscall4(int, clock_nanosleep, const clockid_t, clock, int, flags,
>                const struct timespec *, req, struct timespec *, rem)
>  #endif
> @@ -1205,8 +1206,25 @@ static inline abi_long copy_to_user_timeval(abi_ulong target_tv_addr,
>      return 0;
>  }
>  
> +static inline abi_long copy_from_user_timeval64(struct timeval *tv,
> +                                                abi_ulong target_tv_addr)
> +{
> +    struct target__kernel_sock_timeval *target_tv;
> +
> +    if (!lock_user_struct(VERIFY_READ, target_tv, target_tv_addr, 1)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    __get_user(tv->tv_sec, &target_tv->tv_sec);
> +    __get_user(tv->tv_usec, &target_tv->tv_usec);
> +
> +    unlock_user_struct(target_tv, target_tv_addr, 0);
> +
> +    return 0;
> +}
> +
>  static inline abi_long copy_to_user_timeval64(abi_ulong target_tv_addr,
> -                                             const struct timeval *tv)
> +                                              const struct timeval *tv)
>  {
>      struct target__kernel_sock_timeval *target_tv;
>  
> @@ -6771,6 +6789,87 @@ static inline abi_long host_to_target_timex(abi_long target_addr,
>  }
>  #endif
>  
> +
> +#if defined(TARGET_NR_clock_adjtime64) && defined(CONFIG_CLOCK_ADJTIME)
> +static inline abi_long target_to_host_timex64(struct timex *host_tx,
> +                                              abi_long target_addr)
> +{
> +    struct target__kernel_timex *target_tx;
> +
> +    if (copy_from_user_timeval64(&host_tx->time, target_addr +
> +                                 offsetof(struct target__kernel_timex,
> +                                          time))) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    if (!lock_user_struct(VERIFY_READ, target_tx, target_addr, 1)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    __get_user(host_tx->modes, &target_tx->modes);
> +    __get_user(host_tx->offset, &target_tx->offset);
> +    __get_user(host_tx->freq, &target_tx->freq);
> +    __get_user(host_tx->maxerror, &target_tx->maxerror);
> +    __get_user(host_tx->esterror, &target_tx->esterror);
> +    __get_user(host_tx->status, &target_tx->status);
> +    __get_user(host_tx->constant, &target_tx->constant);
> +    __get_user(host_tx->precision, &target_tx->precision);
> +    __get_user(host_tx->tolerance, &target_tx->tolerance);
> +    __get_user(host_tx->tick, &target_tx->tick);
> +    __get_user(host_tx->ppsfreq, &target_tx->ppsfreq);
> +    __get_user(host_tx->jitter, &target_tx->jitter);
> +    __get_user(host_tx->shift, &target_tx->shift);
> +    __get_user(host_tx->stabil, &target_tx->stabil);
> +    __get_user(host_tx->jitcnt, &target_tx->jitcnt);
> +    __get_user(host_tx->calcnt, &target_tx->calcnt);
> +    __get_user(host_tx->errcnt, &target_tx->errcnt);
> +    __get_user(host_tx->stbcnt, &target_tx->stbcnt);
> +    __get_user(host_tx->tai, &target_tx->tai);
> +
> +    unlock_user_struct(target_tx, target_addr, 0);
> +    return 0;
> +}
> +
> +static inline abi_long host_to_target_timex64(abi_long target_addr,
> +                                              struct timex *host_tx)
> +{
> +    struct target__kernel_timex *target_tx;
> +
> +   if (copy_to_user_timeval64(target_addr +
> +                              offsetof(struct target__kernel_timex, time),
> +                              &host_tx->time)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    if (!lock_user_struct(VERIFY_WRITE, target_tx, target_addr, 0)) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    __put_user(host_tx->modes, &target_tx->modes);
> +    __put_user(host_tx->offset, &target_tx->offset);
> +    __put_user(host_tx->freq, &target_tx->freq);
> +    __put_user(host_tx->maxerror, &target_tx->maxerror);
> +    __put_user(host_tx->esterror, &target_tx->esterror);
> +    __put_user(host_tx->status, &target_tx->status);
> +    __put_user(host_tx->constant, &target_tx->constant);
> +    __put_user(host_tx->precision, &target_tx->precision);
> +    __put_user(host_tx->tolerance, &target_tx->tolerance);
> +    __put_user(host_tx->tick, &target_tx->tick);
> +    __put_user(host_tx->ppsfreq, &target_tx->ppsfreq);
> +    __put_user(host_tx->jitter, &target_tx->jitter);
> +    __put_user(host_tx->shift, &target_tx->shift);
> +    __put_user(host_tx->stabil, &target_tx->stabil);
> +    __put_user(host_tx->jitcnt, &target_tx->jitcnt);
> +    __put_user(host_tx->calcnt, &target_tx->calcnt);
> +    __put_user(host_tx->errcnt, &target_tx->errcnt);
> +    __put_user(host_tx->stbcnt, &target_tx->stbcnt);
> +    __put_user(host_tx->tai, &target_tx->tai);
> +
> +    unlock_user_struct(target_tx, target_addr, 1);
> +    return 0;
> +}
> +#endif
> +
>  static inline abi_long target_to_host_sigevent(struct sigevent *host_sevp,
>                                                 abi_ulong target_addr)
>  {
> @@ -9726,6 +9825,23 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>              }
>          }
>          return ret;
> +#endif
> +#if defined(TARGET_NR_clock_adjtime64) && defined(CONFIG_CLOCK_ADJTIME)
> +    case TARGET_NR_clock_adjtime64:
> +        {
> +            struct timex htx, *phtx = &htx;

I know you have copied the code from TARGET_NR_clock_adjtime, but I
think phtx is totally useless.

> +
> +            if (target_to_host_timex64(phtx, arg2) != 0) {
> +                return -TARGET_EFAULT;
> +            }
> +            ret = get_errno(clock_adjtime(arg1, phtx));
> +            if (!is_error(ret) && phtx) {

value of phtx doesn't change. No need to check.

> +                if (host_to_target_timex64(arg2, phtx) != 0) {
> +                    return -TARGET_EFAULT;
> +                }
> +            }
> +        }
> +        return ret;
>  #endif
>      case TARGET_NR_getpgid:
>          return get_errno(getpgid(arg1));

Thanks,
Laurent