Commit 9c648c17493d3f3382adeef809d76a1b027db57f
2012-07-11T20:10:52
Bugfix: Calculate nsec in nmsleep correctly The old algorithm (msecs * 1000000) - (sec / 1000000000) gets total nsec, including seconds, since the sec/1e9 should be multiplying. It's also vulnerable to easy overflows. Using ldiv gets the quotient and remainder in a single operation (at least on x86) and avoids overflow.
diff --git a/util.c b/util.c
index c6b8204..822e61d 100644
--- a/util.c
+++ b/util.c
@@ -694,9 +694,11 @@ void nmsleep(unsigned int msecs)
{
struct timespec twait, tleft;
int ret;
+ ldiv_t d;
- tleft.tv_sec = msecs / 1000;
- tleft.tv_nsec = (uint64_t)(msecs * 1000000) - (uint64_t)(twait.tv_sec / 1000000000);
+ d = ldiv(msecs, 1000);
+ tleft.tv_sec = d.quot;
+ tleft.tv_nsec = d.rem * 1000000;
do {
twait.tv_sec = tleft.tv_sec;
twait.tv_nsec = tleft.tv_nsec;