Bug#1035375: [Info-mtools] [PATCH] Ensure that directory entries use gmtime(3) over localtime(3).

[Alain Knaff <alain@knaff.lu>]

Hi,

On 07/07/2025 12:29, Chris Hofstaedtler wrote:
> Hi mtools maintainers, Alain,
> 
> it appears the patch posted in 2023 to fix SOURCE_DATE_EPOCH support 
> under non-UTC TZ never made it anywhere. It was posted here:
> https://lists.gnu.org/archive/html/info-mtools/2023-05/msg00000.html
> 
> Could you please take a look and maybe apply it?
> 
> Thanks,
> Chris
> 
> 

I had a look at it, and the whole thing is rather confusing. Discussion 
text seems to be about SOURCE_DATE_EPOCH, but the only patch contained 
here does something else, i.e. changing how the datetime is stored on 
the FAT filesystem.

Currently, mtools matches Windows' behavior:

https://stackoverflow.com/questions/38549583/what-time-zone-does-a-fat32-sd-card-record-timestamps-in :

"... The FAT file system records times on disk in local time. ..."

Apparently some digital cameras do store time in UTC though.


As far as SOURCE_DATE_EPOCH is concerned, this is apparently an integer 
(seconds since epoch), rather than a structured field showing hour/
minute/seconds, so timezone considerations should not really apply.

Regards,

Alain