Date: Mon, 4 Feb 2002 01:35:34 -0500 (EST) From: Mikhail Teterin <mi@aldan.algebra.com> To: FreeBSD-gnats-submit@freebsd.org Subject: bin/34601: bc(1)'s multi-line file parsing problem Message-ID: <200202040635.g146ZY907522@aldan.algebra.com>
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>Number: 34601
>Category: bin
>Synopsis: bc(1)'s multi-line file parsing problem
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Feb 03 22:40:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator: Mikhail Teterin
>Release: FreeBSD 5.0-CURRENT i386
>Organization:
Virtual Estates, Inc.
>Environment:
System: FreeBSD aldan.algebra.com 5.0-CURRENT FreeBSD 5.0-CURRENT #1: Thu Jan 3 21:38:15 EST 2002 mi@aldan.algebra.com:/ccd/obj/ccd/src/sys/DEBUG i386
>Description:
Depending on the weather (or compilation flags) bc's parsing
of multi-line files involving function definitions may break.
This is best manifested, when bc is parsing its own libmath --
triggered by the ``-l'' flag (use_math).
The /usr/src/contrib/bc/bc/libmath.h contains the code of bc's
math-library, which is parsed if the -l flag is given. The code
contains several functions, which are, evidently, defined using
multiple lines -- between the opening ``['' and the closing ``]''.
The code in load_code is not prepared for this. When it sees the
closing ``]'' at line 280 it assumes, that save_adr contains the
address saved when it saw the opening ``[''.
However, save_adr is an atomic variable, which is not initialized
if the opening ``['' occured in one of the previous lines.
Depending on save_adr's value bc will or will not crash shortly
after.
>How-To-Repeat:
I compile everything with
CFLAGS= -O -pipe -march=i686 ${PROG:C/.+/-fomit-frame-pointer/}
which means that bc, whose Makefile declares PROG, was built with
CFLAGS=-O -pipe -march=i686 -fomit-frame-pointer
this was enough for me to stumble upon this on both 5-CURRENT and
4.4-STABLE machines.
echo 20 | bc -l
However, I was able to reproduce it with simple -g.
It works properly on freefall...
>Fix:
Either the save_adr should be made static or the whole libmath needs
to be parsed as one big string. For the former, the patch would be
simple. Not sure about about the latter or something third...
RCS file: /home/ncvs/src/contrib/bc/bc/load.c,v
retrieving revision 1.1.1.2
diff -U2 -r1.1.1.2 load.c
--- load.c 26 Feb 2001 07:12:53 -0000 1.1.1.2
+++ load.c 4 Feb 2002 06:31:12 -0000
@@ -157,5 +157,5 @@
long vaf_name; /* variable, array or function number. */
long func;
- program_counter save_adr;
+ static program_counter save_adr;
/* Initialize. */
>Release-Note:
>Audit-Trail:
>Unformatted:
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