From: Qin Fandong <shell_way@foxmail.com>
Date: Wed, 18 Jan 2023 06:02:53 +0000 (+1100)
Subject: vmstat: precision issues in unitConvert()
X-Git-Tag: v4.0.3_rc1~9
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=0a5ccbdd4273f063344b70be15fb22f3e7c250a6;p=procps-ng

vmstat: precision issues in unitConvert()

Fix conversion errors due to precision issues in function unitConvert

For example: unitConvert(98720620) will return 98720624, not 98720620.

Because we do (unsigned long)(float)98720620 in function unitConvert
and this is wrong! We should do (unsigned long)(double)98720620 here.

Signed-off-by: Craig Small <csmall@dropbear.xyz>

References:
 procps-ng/procps!75
---

diff --git a/NEWS b/NEWS
index cec971ef..40a39e9a 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,7 @@ procps-ng-NEXT
   * vmstat: Referesh memory statistics                     Debian #1027963
   * vmstat: Fix initial si,so,bi,bo,in & cs values         issue #15
                                                            Debian #668580
+  * vmstat: Fix conversion errors due to precision         merge #75
   * w: Add --pids option                                   merge #159
   * watch: Pass through beep                               issue #104
   * watch: -r option to not re-exec on SIGWINCH            merge #125
diff --git a/src/vmstat.c b/src/vmstat.c
index b4bcb8ff..eed130c4 100644
--- a/src/vmstat.c
+++ b/src/vmstat.c
@@ -336,8 +336,8 @@ static void new_header(void)
 
 static unsigned long unitConvert(unsigned long size)
 {
-    float cvSize;
-    cvSize = (float)size / dataUnit * ((statMode == SLABSTAT) ? 1 : 1024);
+    double cvSize;
+    cvSize = (double)size / dataUnit * ((statMode == SLABSTAT) ? 1 : 1024);
     return ((unsigned long)cvSize);
 }