[Privoxy-devel] more time questions

[Lee]

On 5/3/16, Fabian Keil <fk at fabiankeil.de> wrote:
> Lee <ler762 at gmail.com> wrote:
>
>> Right now I'm feeling like I can't read code :(   What's the expected
>> behavior if --enable-strptime-sanity-checks is configured & this bit
>> is added to regression-tests.action after
>> {+hide-if-modified-since{-60} -crunch-if-none-match}
>> # Set Header    = If-Modified-Since: Gee, this date is invalid
>> # Expect Header = REMOVAL
>>
>> # Set Header    = If-Modified-Since: Monday, 01-Jan-2025 00:15:00 GMT
>> # Expect Header = SOME CHANGE
>> # Set Header    = If-Modified-Since: wednesday, 01-Jan-2025 00:15:00 GMT
>> # Expect Header = SOME CHANGE
>>
>> 1/1/2025 can't be both Mon & Wed so shouldn't one of them cause a
>> complaint?
>
> The strptime() sanity check merely confirms that parsing a date format
> generated from a time_t results in the same time_t again.
>
> This happens after the original date has been parsed. If strptime()
> silently ignores incorrect weekdays the expected behaviour is therefore
> that the check does not detect this.

OK.  Not a whole lot of error checking going on, so that explains
that.  Thank you.

Next set of questions is
- does timegm in miscutil.c leak memory on non-windows systems?

      old_zone = malloc(3 + strlen(zone) + 1);
         ...
#ifdef _WIN32
         free(old_zone);
#endif /* def _WIN32 */

Seems like the code should be doing a free regardless of _WIN32 being
defined or not.


- is there a timing window in miscutil.c timegm that can change TZ to "UTC"?

Unless each thread get it's own copy of environment variables, it
seems like one thread can do
   zone = getenv("TZ");
   putenv("TZ=UTC");
   tzset();

another thread comes along and does
   zone = getenv("TZ");
which gets the current TZ=UTC

the first thread finishes up with
         putenv(old_zone);
   tzset();

and then the other thread does the putenv / tzset and TZ is
permanently changed to UTC.

Thanks,
Lee