From: Tim Wiederhake <twiederh@redhat.com>
Date: Mon, 1 Feb 2021 12:42:04 +0000 (+0100)
Subject: virhostuptime: Fix rounding in uptime calculation
X-Git-Tag: v7.1.0-rc1~336
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2cdbfbe7ac40a161a7c56bf1723183e3c98a2073;p=thirdparty%2Flibvirt.git

virhostuptime: Fix rounding in uptime calculation

"f + 0.5" does not round correctly for values very close to
".5" for every integer multiple, e.g. "0.499999975".

Found by clang-tidy's "bugprone-incorrect-roundings" check.

Signed-off-by: Tim Wiederhake <twiederh@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---

diff --git a/src/util/virhostuptime.c b/src/util/virhostuptime.c
index 696a38fbb5..7508a5a9b6 100644
--- a/src/util/virhostuptime.c
+++ b/src/util/virhostuptime.c
@@ -32,6 +32,8 @@
 #include "virtime.h"
 #include "virthread.h"
 
+#include <math.h>
+
 #define VIR_FROM_THIS VIR_FROM_NONE
 
 VIR_LOG_INIT("util.virhostuptime");
@@ -76,7 +78,7 @@ virHostGetBootTimeProcfs(unsigned long long *btime)
         return -EINVAL;
     }
 
-    *btime = now / 1000 - up + 0.5;
+    *btime = llround(now / 1000 - up);
 
     return 0;
 }