Re: [PATCH 15/16] linux: Add {f}stat{at} y2038 support

[Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>]

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On 24/07/2020 07:53, Lukasz Majewski wrote:
>>  
>> diff --git a/sysdeps/unix/sysv/linux/fstatat.c
>> b/sysdeps/unix/sysv/linux/fstatat.c index 03ddb3f493..f65d3b74a6
>> 100644 --- a/sysdeps/unix/sysv/linux/fstatat.c
>> +++ b/sysdeps/unix/sysv/linux/fstatat.c
>> -#  ifdef __NR_fstatat64
>> -  /* Old KABIs with old non-LFS support, e.g. arm, i386, hppa, m68k,
>> mips32,
>> -     microblaze, s390, sh, powerpc, and sparc.  */
>> +  struct statx stx;
>> +  int r = INLINE_SYSCALL_CALL (statx, fd, file, flag,
>> STATX_BASIC_STATS,
>> +			       &stx);
> 
> I'm wondering about the indentation here - I do see 3*TAB and some
> spaces. Shouldn't we only use spaces?

Afaik the GNU code guidelines requires to use TAB indentations instead
of space in this case.  


> 
> And one more question what is the correct alignment:
> 		(statx, fd, file, flag
> 		 &stx);
> 
> or
> 		(statx, fd, file, flag
> 		&stx);

My understanding the latter.

> 
>> +  if (r == 0 || errno != ENOSYS)
>> +    {
>> +      if (r == 0)
>> +	__cp_stat_t64_statx (st, &stx);
>> +      return r;
>> +    }
> 
> Great that the statx is used here.
> 
>> +
>> +# ifdef __NR_fstatat64
>> +  /* Both new kABI which uses generic pre 64-bit time Linux ABI
>> (e.g. csky
>> +     and nios) and old kABI with non-LFS support (e.g. arm, i386,
>> hppa, m68k,
>> +     mips32, microblaze, s390, sh, powerpc, and sparc32).  */
>>    struct stat64 st64;
>> -  int r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
>> +  r = INLINE_SYSCALL_CALL (fstatat64, fd, file, &st64, flag);
>>    if (r == 0)
>>      {
>>        if (! in_ino_t_range (st64.st_ino)
>> @@ -48,7 +51,7 @@ __fstatat (int fd, const char *file, struct stat
>> *st, int flag) || ! in_blkcnt_t_range (st64.st_blocks))
>>  	return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
>>  
>> -      /* Clear internal pad and reserved fields.  */
>> +      /* Clear both pad and reserved fields.  */
>>        memset (st, 0, sizeof (*st));
>>  
>>        st->st_dev = st64.st_dev,
>> @@ -61,22 +64,29 @@ __fstatat (int fd, const char *file, struct stat
>> *st, int flag) st->st_size = st64.st_size;
>>        st->st_blksize = st64.st_blksize;
>>        st->st_blocks  = st64.st_blocks;
>> -      st->st_atim.tv_sec = st64.st_atim.tv_sec;
>> -      st->st_atim.tv_nsec = st64.st_atim.tv_nsec;
>> -      st->st_mtim.tv_sec = st64.st_mtim.tv_sec;
>> -      st->st_mtim.tv_nsec = st64.st_mtim.tv_nsec;
>> -      st->st_ctim.tv_sec = st64.st_ctim.tv_sec;
>> -      st->st_ctim.tv_nsec = st64.st_ctim.tv_nsec;
>> +      st->st_atim = valid_timespec_to_timespec64 (st64.st_atim);
>> +      st->st_mtim = valid_timespec_to_timespec64 (st64.st_mtim);
>> +      st->st_ctim = valid_timespec_to_timespec64 (st64.st_ctim);
>>      }
>>    return r;
>> -#  else
>> +# else
>>    /* 64-bit kabi outlier, e.g. mips64 and mips64-n32.  */
>>    struct kernel_stat kst;
>> -  int r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
>> -  return r ?: __cp_kstat_stat (&kst, st);
>> -#  endif /* __nr_fstatat64  */
>> -# endif /* STAT_IS_KERNEL_STAT  */
>> +  r = INTERNAL_SYSCALL_CALL (newfstatat, fd, file, &kst, flag);
>> +  return r ?: __cp_kstat_stat_t64 (&kst, st);
>> +# endif /* __NR_fstatat64  */
>> +}
>> +# if __TIMESIZE != 64
>> +libc_hidden_def (__fstatat_time64)
>> +
>> +int
>> +__fstatat (int fd, const char *file, struct stat *buf, int flags)
>> +{
>> +  struct __stat_t64 st_t64;
>> +  return __fstatat_time64 (fd, file, &st_t64, flags)
>> +	 ?: __cp_stat_t64_stat (&st_t64, buf);
>>  }
>> +# endif
>>  
>>  weak_alias (__fstatat, fstatat)
>>  #endif
>> diff --git a/sysdeps/unix/sysv/linux/fstatat64.c
>> b/sysdeps/unix/sysv/linux/fstatat64.c index 82fab107a5..b3940f0d20
>> 100644 --- a/sysdeps/unix/sysv/linux/fstatat64.c
>> +++ b/sysdeps/unix/sysv/linux/fstatat64.c
>> @@ -19,56 +19,102 @@
>>  #define __fstatat __redirect___fstatat
>>  #define fstatat   __redirect_fstatat
>>  #include <sys/stat.h>
>> -#undef __fstatat
>> -#undef fstatat
>>  #include <fcntl.h>
>> -
>> +#include <string.h>
>>  #include <kernel_stat.h>
>>  #include <sysdep.h>
>> -
>> +#include <time.h>
>>  #include <statx_cp.h>
>>  #include <kstat_cp.h>
>> +#include <stat_t64_cp.h>
>>  
>>  int
>> -__fstatat64 (int fd, const char *file, struct stat64 *st, int flag)
>> +__fstatat64_time64 (int fd, const char *file, struct __stat64_t64
>> *st,
>> +		    int flag)
>>  {
>> +  int r;
>> +
>> +#if (__WORDSIZE == 32 \
>> +     && (!defined __SYSCALL_WORDSIZE || __SYSCALL_WORDSIZE == 32))
> 
> I do guess that the above condition is to ensure that 32 bit archs
> (excluding x86_64-x32 - e.g. arm, riscv, etc) use statx?

Yes, this is similar for what is done by SysVIPC fixes. 


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