On Wed, May 15, 2024, at 09:30, maobibo wrote:
> On 2024/5/11 下午8:17, Arnd Bergmann wrote:
>> On Sat, May 11, 2024, at 12:01, Huacai Chen wrote:
>>
>> Importantly, we can't just add fstatat64() on riscv32 because
>> there is no time64 version for it other than statx(), and I don't
>> want the architectures to diverge more than necessary.
> yes, I agree. Normally there is newfstatat() on 64-bit architectures but
> fstatat64() on 32-bit ones.
>
> I do not understand why fstatat64() can be added for riscv32 still.
> 32bit timestamp seems works well for the present, it is valid until
> (0x1UL << 32) / 365 / 24 / 3600 + 1970 == 2106 year. Year 2106 should
> be enough for 32bit system.
There is a very small number of interfaces for which we ended up
not using a 64-bit time_t replacement, but those are only for
relative times, not epoch based offsets. The main problems
here are:
- time_t is defined to be a signed value in posix, and we need
to handle file timestamps before 1970 in stat(), so changing
this one to be unsigned is not an option.
- A lot of products have already shipped that will have to
be supported past 2038 on existing 32-bit hardware. We
cannot regress on architectures that have already been
fixed to support this.
- file timestamps can also be set into the future, so applications
relying on this are broken before 2038.
Arnd
