[1/5] linux: Implement fstatat with __fstatat64_time64

  It makes fstatat use __NR_statx, which fix the s390 issue with
missing nanoxsecond support on compat stat syscalls (at least
on recent kernels) and limits the statx call to only one function
(which simplifies the __ASSUME_STATX support).

Checked on i686-linux-gnu and on powerpc-linux-gnu.
---
 sysdeps/unix/sysv/linux/fstatat.c | 52 +++++++------------------------
 1 file changed, 11 insertions(+), 41 deletions(-)
  

On 19/03/2021 19:31, Adhemerval Zanella via Libc-alpha wrote:
> It makes fstatat use __NR_statx, which fix the s390 issue with
> missing nanoxsecond support on compat stat syscalls (at least
> on recent kernels) and limits the statx call to only one function
> (which simplifies the __ASSUME_STATX support).
> 
> Checked on i686-linux-gnu and on powerpc-linux-gnu.
> ---

Hi Adhemerval,

I've applied your series and on s390, io/tst-stat is now passing as stat
is now using statx and the nanosecond fields are not zero anymore.

Thanks,
Stefan
  

On 19/03/2021 19:31, Adhemerval Zanella via Libc-alpha wrote:
> It makes fstatat use __NR_statx, which fix the s390 issue with
> missing nanoxsecond support on compat stat syscalls (at least
> on recent kernels) and limits the statx call to only one function
> (which simplifies the __ASSUME_STATX support).
> 
> Checked on i686-linux-gnu and on powerpc-linux-gnu.
> ---
>  sysdeps/unix/sysv/linux/fstatat.c | 52 +++++++------------------------
>  1 file changed, 11 insertions(+), 41 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/fstatat.c b/sysdeps/unix/sysv/linux/fstatat.c
> index 59efff615f..618c254d6f 100644
> --- a/sysdeps/unix/sysv/linux/fstatat.c
> +++ b/sysdeps/unix/sysv/linux/fstatat.c
> @@ -26,33 +26,19 @@
>  int
>  __fstatat (int fd, const char *file, struct stat *buf, int flag)
>  {
> -  int r;
> -
> -# if STAT_IS_KERNEL_STAT
> -  /* New kABIs which uses generic pre 64-bit time Linux ABI, e.g.
> -     csky, nios2  */
> -  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
> -  if (r == 0 && (buf->__st_ino_pad != 0
> -		 || buf->__st_size_pad != 0
> -		 || buf->__st_blocks_pad != 0))
> -    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
> -# else
> -#  ifdef __NR_fstatat64
> -  /* Old KABIs with old non-LFS support, e.g. arm, i386, hppa, m68k, mips32,
> -     microblaze, s390, sh, powerpc, and sparc.  */
> -  struct stat64 st64;
> -  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
> +  struct __stat64_t64 st64;
> +  int r = __fstatat64_time64 (fd, file, &st64, flag);
>    if (r == 0)
>      {
>        if (! in_ino_t_range (st64.st_ino)
>  	  || ! in_off_t_range (st64.st_size)
> -	  || ! in_blkcnt_t_range (st64.st_blocks))
> +	  || ! in_blkcnt_t_range (st64.st_blocks)
> +	  || ! in_time_t_range (st64.st_atim.tv_sec)
> +	  || ! in_time_t_range (st64.st_mtim.tv_sec)
> +	  || ! in_time_t_range (st64.st_ctim.tv_sec))
>  	return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
OK
> 
> -      /* Clear internal pad and reserved fields.  */
> -      memset (buf, 0, sizeof (*buf));
Do we have to clear the user provided struct as before?

> -
> -      buf->st_dev = st64.st_dev,
> +      buf->st_dev = st64.st_dev;
>        buf->st_ino = st64.st_ino;
>        buf->st_mode = st64.st_mode;
>        buf->st_nlink = st64.st_nlink;
> @@ -62,27 +48,11 @@ __fstatat (int fd, const char *file, struct stat *buf, int flag)
>        buf->st_size = st64.st_size;
>        buf->st_blksize = st64.st_blksize;
>        buf->st_blocks  = st64.st_blocks;
> -      buf->st_atim.tv_sec = st64.st_atim.tv_sec;
> -      buf->st_atim.tv_nsec = st64.st_atim.tv_nsec;
> -      buf->st_mtim.tv_sec = st64.st_mtim.tv_sec;
> -      buf->st_mtim.tv_nsec = st64.st_mtim.tv_nsec;
> -      buf->st_ctim.tv_sec = st64.st_ctim.tv_sec;
> -      buf->st_ctim.tv_nsec = st64.st_ctim.tv_nsec;
> -
> -      return 0;
> +      buf->st_atim = valid_timespec64_to_timespec (st64.st_atim);
> +      buf->st_mtim = valid_timespec64_to_timespec (st64.st_mtim);
> +      buf->st_ctim = valid_timespec64_to_timespec (st64.st_ctim);
>      }
> -#  else
> -  /* 64-bit kabi outlier, e.g. mips64 and mips64-n32.  */
> -  struct kernel_stat kst;
> -  r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
> -  if (r == 0)
> -    r = __cp_kstat_stat (&kst, buf);
> -#  endif /* __nr_fstatat64  */
> -# endif /* STAT_IS_KERNEL_STAT  */
> -
> -  return INTERNAL_SYSCALL_ERROR_P (r)
> -	 ? INLINE_SYSCALL_ERROR_RETURN_VALUE (-r)
> -	 : 0;
> +  return r;
>  }
> 
>  weak_alias (__fstatat, fstatat)
> 
OK
  

On 26/03/2021 06:24, Stefan Liebler via Libc-alpha wrote:
> On 19/03/2021 19:31, Adhemerval Zanella via Libc-alpha wrote:
>> It makes fstatat use __NR_statx, which fix the s390 issue with
>> missing nanoxsecond support on compat stat syscalls (at least
>> on recent kernels) and limits the statx call to only one function
>> (which simplifies the __ASSUME_STATX support).
>>
>> Checked on i686-linux-gnu and on powerpc-linux-gnu.
>> ---
>>  sysdeps/unix/sysv/linux/fstatat.c | 52 +++++++------------------------
>>  1 file changed, 11 insertions(+), 41 deletions(-)
>>
>> diff --git a/sysdeps/unix/sysv/linux/fstatat.c b/sysdeps/unix/sysv/linux/fstatat.c
>> index 59efff615f..618c254d6f 100644
>> --- a/sysdeps/unix/sysv/linux/fstatat.c
>> +++ b/sysdeps/unix/sysv/linux/fstatat.c
>> @@ -26,33 +26,19 @@
>>  int
>>  __fstatat (int fd, const char *file, struct stat *buf, int flag)
>>  {
>> -  int r;
>> -
>> -# if STAT_IS_KERNEL_STAT
>> -  /* New kABIs which uses generic pre 64-bit time Linux ABI, e.g.
>> -     csky, nios2  */
>> -  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, buf, flag);
>> -  if (r == 0 && (buf->__st_ino_pad != 0
>> -		 || buf->__st_size_pad != 0
>> -		 || buf->__st_blocks_pad != 0))
>> -    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
>> -# else
>> -#  ifdef __NR_fstatat64
>> -  /* Old KABIs with old non-LFS support, e.g. arm, i386, hppa, m68k, mips32,
>> -     microblaze, s390, sh, powerpc, and sparc.  */
>> -  struct stat64 st64;
>> -  r = INTERNAL_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
>> +  struct __stat64_t64 st64;
>> +  int r = __fstatat64_time64 (fd, file, &st64, flag);
>>    if (r == 0)
>>      {
>>        if (! in_ino_t_range (st64.st_ino)
>>  	  || ! in_off_t_range (st64.st_size)
>> -	  || ! in_blkcnt_t_range (st64.st_blocks))
>> +	  || ! in_blkcnt_t_range (st64.st_blocks)
>> +	  || ! in_time_t_range (st64.st_atim.tv_sec)
>> +	  || ! in_time_t_range (st64.st_mtim.tv_sec)
>> +	  || ! in_time_t_range (st64.st_ctim.tv_sec))
>>  	return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
> OK
>>
>> -      /* Clear internal pad and reserved fields.  */
>> -      memset (buf, 0, sizeof (*buf));
> Do we have to clear the user provided struct as before?

I think it is not strictly required, but some architecture does
have padding and reserved fields.  I will reinstate it, the compiler
should have enough information to only zero the fields not actively
set.