Date: Thu, 6 Apr 2000 02:06:54 -0700 (PDT) From: jdg@debian.org To: freebsd-gnats-submit@FreeBSD.org Subject: bin/17824: [PATCH] /usr/bin/column has arithmetic overflows Message-ID: <200004060906.CAA43220@freefall.freebsd.org>
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>Number: 17824
>Category: bin
>Synopsis: [PATCH] /usr/bin/column has arithmetic overflows
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Apr 6 02:10:01 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: Julian Gilbey
>Release: I'm not (but it's still a bug in latest CVS)
>Organization:
>Environment:
N/A
>Description:
I discovered that column gave divide-by-zero errors in certain
situations (specifically, if the number of display columns is c and
the widest item of data has width w, then letting w8 = 8*((w+8)/8)
(rounding down to the nearest int), the error will occur if w<c<w8).
The patch in the "Fix" section below corrects this bug. (It's not
obvious because usually c=80, so we cannot have w<c<w8.)
>How-To-Repeat:
polya:~ $ cat > /tmp/72
123456789012345678901234567890123456789012345678901234567890123456789012
polya:~ $ column -c 79 </tmp/72
Floating point exception
polya:~ $
>Fix:
[This patch won't work directly because of tab->space conversion.]
--- column.c.orig Thu Mar 25 02:47:47 1999
+++ column.c Wed Apr 5 23:42:31 2000
@@ -145,6 +145,10 @@
maxlength = (maxlength + TAB) & ~(TAB - 1);
numcols = termwidth / maxlength;
+ if (!numcols) {
+ print();
+ exit(eval);
+ }
endcol = maxlength;
for (chcnt = col = 0, lp = list;; ++lp) {
chcnt += printf("%s", *lp);
@@ -173,6 +177,10 @@
maxlength = (maxlength + TAB) & ~(TAB - 1);
numcols = termwidth / maxlength;
+ if (!numcols) {
+ print();
+ exit(eval);
+ }
numrows = entries / numcols;
if (entries % numcols)
++numrows;
>Release-Note:
>Audit-Trail:
>Unformatted:
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