Dubious arithmetic

[stedolan]

mtime_stubs.c calculates time in nanoseconds using:

(now.tv_sec - start.tv_sec) * 1000000000 + (now.tv_nsec - start.tv_nsec)

This does arithmetic at type time_t. If that's 32-bit, this will overflow in a few seconds. It should use 64-bit arithmetic explicitly, either with casts or temporaries, e.g:

(int64)(now.tv_sec - start.tv_sec) * (int64)1000000000 + 
    (int64)(now.tv_nsec - start.tv_nsec)

or

int64 time = now.tv_sec - start.tv_sec;
time *= 1000000000;
time += now.tv_nsec - start.tv_nsec

My system has a 64-bit time_t, so I haven't actually tested any of this :)

[dbuenzli]

Damned ! Well spotted. Thanks.

I tested it, both the bug and the fix.