From: Guy Harris <guy@alum.mit.edu>
Date: Thu, 3 Oct 2019 16:27:36 +0000 (-0700)
Subject: With MSVC, abort if _BitScanForward() returns 0.
X-Git-Tag: libpcap-1.10-bp~413
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/3b9b6100912f7bb1ee43f9cfb51e804765a37bd4

With MSVC, abort if _BitScanForward() returns 0.

It should never return zero, as never pass a value of 0 to
lowest_set_bit(), but this should keep Coverity from getting upset (as a
result of not understanding _BitScanForward() well enough to realize
that if it's passed a non-zero value it will never return 0).

Reported by Charles Smith at Tangible Security.
---

diff --git a/optimize.c b/optimize.c
index 283a6de3..e38d2d7c 100644
--- a/optimize.c
+++ b/optimize.c
@@ -137,7 +137,7 @@ lowest_set_bit(int mask)
 	 * (It's currently not, in MSVC, even on 64-bit platforms, but....)
 	 */
 	if (_BitScanForward(&bit, (unsigned int)mask) == 0)
-		return -1;	/* mask is zero */
+		abort();	/* mask is zero */
 	return (int)bit;
 }
 #elif defined(MSDOS) && defined(__DJGPP__)