Forum OpenACS Development: localtime_s

Dear all,

please notice that in the file reentrant.c the following lines

    int errNum;

    NS_NONNULL_ASSERT(clock != NULL);

    errNum = localtime_s(&tlsPtr->ltbuf, clock);
    if (errNum != 0) {
        NsThreadFatal("ns_localtime", "localtime_s", errNum);
    }

when compiled with MS VC 2019 x64, do compile but break at run time, with errno = 22, while the following lines

    Tls *tlsPtr = GetTls();
    errno_t errNum;

    NS_NONNULL_ASSERT(clock != NULL);
 
    errNum = _localtime32_s(&tlsPtr->ltbuf, clock);
    if (errNum != 0) {
        NsThreadFatal("ns_localtime", "_localtime32_s", errNum);
    }

though generating a warning at compile time, do not break at run time.

Hope it helps, Maurizio

Dear Gustaf,
thank you for fixing the code!

Trying to answer your question, I believe that yes the problem was there, hidden in the code, but that it actually got exposed only recently (24th of January) when in the file winthread.c the following two lines

wait.usec /= 1000;
if (wait.sec < 0 || (wait.sec == 0 && wait.usec <= 0)) {

got changed into

msec = Ns_TimeToMilliseconds(&wait);
if (msec < 0) {

So the function Ns_TimeToMilliseconds got called and the problem exposed.

Again thank you,
Maurizio

Dear Gustaf,
first of all sorry if I continue this discussion where I started it. Next similar issue will be published on Naviserver developer list. Anyhow I had to change your fix into this:
errNum = _localtime32_s(&tlsPtr->ltbuf, clock);
/*
if (sizeof(clock) == 4) {
errNum = _localtime32_s(&tlsPtr->ltbuf, clock);
} else {
errNum = _localtime64_s(&tlsPtr->ltbuf, clock);
}
*/
Why? Because the parameter const time_t *clock comes/goes from/to the "sec" field of variables of type Ns_Time, that is:
typedef struct Ns_Time {
long sec;
long usec;
} Ns_Time;
So, basically, we are mixing up "long" with "time_t". But these two types do not have the same size in Windows 64, where, we have:
sizeof(long) = 4.
sizeof(time_t) = 8.
sizeof(__time32_t) = 4.
while on Linux 64, we have:
sizeof(long) = 8.
sizeof(time_t) = 8.
I hope this clarifies the issue,
Maurizio

Thank you Gustaf,
once the bug in sched.c is removed, you can come back to the original implementation of ns_localtime, leaving the code cleaner:
struct tm *
ns_localtime(const time_t *timep)
{

Tls *tlsPtr = GetTls();
int errNum;

NS_NONNULL_ASSERT(timep != NULL);

errNum = localtime_s(&tlsPtr->ltbuf, timep);
if (errNum != 0) {
NsThreadFatal("ns_localtime", "localtime_s", errNum);
}

return &tlsPtr->ltbuf;
}
Again thank you,
Maurizio

Well... actually no!
The compiler inserts automatically the proper version of the function to be called. This is definition found in the actual Microsoft time.h file used in 64 bit:
_Check_return_wat_
static __inline errno_t __CRTDECL localtime_s(
_Out_ struct tm* const _Tm,
_In_ time_t const* const _Time
)
{
return _localtime64_s(_Tm, _Time);
}
So there's no need to check which of the two versions are to be used. I wrote the previous remark after having first checked the proper functioning of the system with the fix I proposed.

Anyhow it is your call.

Maurizio

Sorry, I will try to explain better my point.

The following is from Microsoft docs:
"localtime_s is an inline function which evaluates to _localtime64_s, and time_t is equivalent to __time64_t. If you need to force the compiler to interpret time_t as the old 32-bit time_t, you can define _USE_32BIT_TIME_T. Doing this will cause localtime_s to evaluate to _localtime32_s. This is not recommended because your application may fail after January 18, 2038, and it is not allowed on 64-bit platforms."

In other words, it doesn't matter if you compile with the 32 bit or 64 bit compiler: if you do not specify that define, time_t is equivalent to __time64_t and localtime_s to _localtime64_s; on the contrary if you specify that define, something you can do only with the 32 bit compiler, time_t is equivalent to __time_32_s and localtime_s is equivalent to _localtime32_s.

Naviserver build system, especially the file "Makefile.win32" already takes properly care of this define (_USE_32BIT_TIME_T).

So nothing needs to be done in the "reentrant.c" code.