Re: [Swarm-Support] SWARM;SantaFE Stock Market

[Paul Johnson]

Marcus G. Daniels wrote:
> Steve Railsback wrote:
>   
> > (The code compiled in Fedora, but it immediately crashed with an 
> > obscure buffer overflow.)
> >     
> Toward the end of the method -createTimePlots in Output.m on line 318 
> the character array `name[10]' is defined.
> Make it `name[20]' and this crash should go away.   It does for me.    
> It's a stack overflow problem that corrupts the variable asmModelParams 
> on line 150 of ASMObserverSwarm.m.
>
>
>   
OK, this banter caused my brain to engage. I think I saw these problems 
before sometime, and thought I had fixed them back then, but must have 
forgotten.

Marcis is certainly right about the overflow. I notice the new-ish gcc 
gives much better warnings than it did in 2003 when I worked on this the 
last time. Check this out, where it points exactly at the offender:

gcc -c -g -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions 
-fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 
-mtune=generic -fasynchronous-unwind-tables -fgnu-runtime 
-fno-strict-aliasing -Wall -Wno-import -Wno-protocol -Wno-long-long 
-D_GNU_SOURCE -DAPPNAME=asm -DAPPVERSION=2.1.1 
address@hidden -I/usr/include/swarm Output.m
Output.m: In function ‘-[Output createTimePlots]’:
Output.m:319: warning: call to __builtin___sprintf_chk will always 
overflow destination buffer
Output.m:320: warning: call to __builtin___sprintf_chk will always 
overflow destination buffer
Output.m:321: warning: call to __builtin___sprintf_chk will always 
overflow destination buffer
Output.m:322: warning: call to __builtin___sprintf_chk will always 
overflow destination buffer

I'll fix up this one and the other thing that was mentioned concerning 
random and make a new post on Sourceforge. I am going to try to re-learn 
how to put an updated ASM on Sourceforge.

Until I figure that out, the new one is posted here:

http://pj.freefaculty.org/Swarm/MySwarmCode/ASM-2.4.1.tar.gz

Funny how time flies. I notice now that my CVS from that program is all 
hacked up with something I was working on during the week when the US 
invaded Iraq the second time, so you imagine it might take me a while to 
figure it out. I'm sure I was doing some updates to comply with gcc 
warnings, but most of those annoying spurious warnings seem to have gone 
away.


I hasten to mention that this does not address the original author's 
question about AgentManager, because that is in the Objective C version 
of ASM that was written for NeXT, and I think in that one it is really 
necessary to rename, rather than comment out the random usage. But that 
one never was my primary interest, I only posted it because I knew some 
people were trying to understand lots of subtle parameter changes.

--
Paul E. Johnson                       email: address@hidden
Professor, Political Science          http://pj.freefaculty.org
1541 Lilac Lane, Rm 504                              
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66044-3177           FAX: (785) 864-5700