Re: [PATCH v2 2/2] linux-user: Add support for utimensat_time64() and semtimedop_time64()

[Laurent Vivier <laurent@vivier.eu>]

Le 25/08/2020 à 16:23, Laurent Vivier a écrit :
> Le 25/08/2020 à 09:18, Laurent Vivier a écrit :
>> Le 25/08/2020 à 00:30, Filip Bozuta a écrit :
>>> This patch introduces functionality for following time64 syscalls:
>>>
>>> *utimensat_time64()
>>>
>>>     int utimensat(int dirfd, const char *pathname,
>>>                   const struct timespec times[2], int flags);
>>>     -- change file timestamps with nanosecond precision --
>>>     man page: https://man7.org/linux/man-pages/man2/utimensat.2.html
>>>
>>> *semtimedop_time64()
>>>
>>>     int semtimedop(int semid, struct sembuf *sops, size_t nsops,
>>>                    const struct timespec *timeout);
>>>     -- System V semaphore operations --
>>>     man page: https://www.man7.org/linux/man-pages/man2/semtimedop.2.html
>>>
>>> Implementation notes:
>>>
>>>    Syscall 'utimensat_time64()' is implemented in similar way as its
>>>    regular variants only difference being that time64 converting function
>>>    is used to convert values of 'struct timespec' between host and target
>>>    ('target_to_host_timespec64()').
>>>
>>>    For syscall 'semtimedop_time64()' and additional argument is added
>>>    in function 'do_semtimedop()' through which the aproppriate 'struct timespec'
>>>    converting function is called (false for regular target_to_host_timespec()
>>>    and true for target_to_host_timespec64()). For 'do_ipc()' a
>>>    check was added as that additional argument: 'TARGET_ABI_BITS == 64'.
>>>
>>> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
>>> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
>>> ---
>>>  linux-user/syscall.c | 60 ++++++++++++++++++++++++++++++++++++--------
>>>  1 file changed, 50 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>>> index fc6a6e32e4..4d460af744 100644
>>> --- a/linux-user/syscall.c
>>> +++ b/linux-user/syscall.c
>>> @@ -1253,7 +1253,8 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts,
>>>  #endif
>>>  
>>>  #if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64) || \
>>> -    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64)
>>> +    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64) || \
>>> +    defined(TARGET_NR_utimensat_time64) || defined(TARGET_NR_semtimedop_time64)
>>>  static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
>>>                                                   abi_ulong target_addr)
>>>  {
>>> @@ -4117,7 +4118,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
>>>  }
>>>  
>>>  #if defined(TARGET_NR_ipc) || defined(TARGET_NR_semop) || \
>>> -    defined(TARGET_NR_semtimedop)
>>> +    defined(TARGET_NR_semtimedop) || defined(TARGET_NR_semtimedop_time64)
>>>  
>>>  /*
>>>   * This macro is required to handle the s390 variants, which passes the
>>> @@ -4134,7 +4135,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
>>>  static inline abi_long do_semtimedop(int semid,
>>>                                       abi_long ptr,
>>>                                       unsigned nsops,
>>> -                                     abi_long timeout)
>>> +                                     abi_long timeout, bool time64)
>>>  {
>>>      struct sembuf sops[nsops];
>>>      struct timespec ts, *pts = NULL;
>>> @@ -4142,8 +4143,14 @@ static inline abi_long do_semtimedop(int semid,
>>>  
>>>      if (timeout) {
>>>          pts = &ts;
>>> -        if (target_to_host_timespec(pts, timeout)) {
>>> -            return -TARGET_EFAULT;
>>> +        if (time64) {
>>> +            if (target_to_host_timespec64(pts, timeout)) {
>>> +                return -TARGET_EFAULT;
>>> +            }
>>> +        } else {
>>> +            if (target_to_host_timespec(pts, timeout)) {
>>> +                return -TARGET_EFAULT;
>>> +            }
>>>          }
>>>      }
>>>  
>>> @@ -4657,7 +4664,7 @@ static abi_long do_ipc(CPUArchState *cpu_env,
>>>  
>>>      switch (call) {
>>>      case IPCOP_semop:
>>> -        ret = do_semtimedop(first, ptr, second, 0);
>>> +        ret = do_semtimedop(first, ptr, second, 0, false);
>>>          break;
>>>      case IPCOP_semtimedop:
>>>      /*
>>> @@ -4667,9 +4674,9 @@ static abi_long do_ipc(CPUArchState *cpu_env,
>>>       * to a struct timespec where the generic variant uses fifth parameter.
>>>       */
>>>  #if defined(TARGET_S390X)
>>> -        ret = do_semtimedop(first, ptr, second, third);
>>> +        ret = do_semtimedop(first, ptr, second, third, TARGET_ABI_BITS == 64);
>>>  #else
>>> -        ret = do_semtimedop(first, ptr, second, fifth);
>>> +        ret = do_semtimedop(first, ptr, second, fifth, TARGET_ABI_BITS == 64);
>>>  #endif
>>>          break;
>>>  
>>> @@ -9887,11 +9894,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>>>  #endif
>>>  #ifdef TARGET_NR_semop
>>>      case TARGET_NR_semop:
>>> -        return do_semtimedop(arg1, arg2, arg3, 0);
>>> +        return do_semtimedop(arg1, arg2, arg3, 0, false);
>>>  #endif
>>>  #ifdef TARGET_NR_semtimedop
>>>      case TARGET_NR_semtimedop:
>>> -        return do_semtimedop(arg1, arg2, arg3, arg4);
>>> +        return do_semtimedop(arg1, arg2, arg3, arg4, false);
>>> +#endif
>>> +#ifdef TARGET_NR_semtimedop_time64
>>> +    case TARGET_NR_semtimedop_time64:
>>> +        return do_semtimedop(arg1, arg2, arg3, arg4, true);
>>>  #endif
>>>  #ifdef TARGET_NR_semctl
>>>      case TARGET_NR_semctl:
>>> @@ -11938,6 +11949,35 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>>>          }
>>>          return ret;
>>>  #endif
>>> +#ifdef TARGET_NR_utimensat_time64
>>> +    case TARGET_NR_utimensat_time64:
>>> +        {
>>> +            struct timespec *tsp, ts[2];
>>> +            if (!arg3) {
>>> +                tsp = NULL;
>>> +            } else {
>>> +                if (target_to_host_timespec64(ts, arg3)) {
>>> +                    return -TARGET_EFAULT;
>>> +                }
>>> +                if (target_to_host_timespec64(ts + 1, arg3 +
>>> +                                     sizeof(struct target__kernel_timespec))) {
>>> +                    return -TARGET_EFAULT;
>>> +                }
>>> +                tsp = ts;
>>> +            }
>>> +            if (!arg2)
>>> +                ret = get_errno(sys_utimensat(arg1, NULL, tsp, arg4));
>>> +            else {
>>> +                p = lock_user_string(arg2);
>>> +                if (!p) {
>>> +                    return -TARGET_EFAULT;
>>> +                }
>>> +                ret = get_errno(sys_utimensat(arg1, path(p), tsp, arg4));
>>> +                unlock_user(p, arg2, 0);
>>> +            }
>>> +        }
>>> +        return ret;
>>> +#endif
>>>  #ifdef TARGET_NR_futex
>>>      case TARGET_NR_futex:
>>>          return do_futex(arg1, arg2, arg3, arg4, arg5, arg6);
>>>
>>
>> Applied to my linux-user-for-5.2 branch.
> 
> I have removed it from my queue because the "TARGET_NR_utimensat_time64"
> part breaks something (at least with sh4/sid on x86_64):
> 
> $ touch a
> $ cp -p a b
> /usr/bin/cp: preserving times for 'b': Invalid argument

In fact, on sh4, he timespec64 conversion is broken for all syscalls.
tv_sec is ok but tv_nsec is totally corrupted (as it would be only a
32bit value).

Thanks,
Laurent