Re: investigating a core dump...

27 Nov 2001


      ...
Optimally, the complete source of the program (if it's large, not
posted to the list, but perhaps put on a web site) and instructions
how to reproduce the bug.
You can find the complete source code at
    ftp://ftp.dfd.dlr.de/put/eicksch/GPC/antdb.pas
The core dump happens some where around line 520. The file processed
is "./sp21_22/ROCK00.E00", name1 is "sp21_22", kbd is "."
The output is like that:
---- snip -----------------------------------------------
ROCK00.AAT gefunden, anzparam = 14, lds = 224, anzds = 1802 ...
Suche PAT
suchstr = ROCK00.PAT ls = 10
(...)
-2.4382450E+06 1.5352708E+06-2.4382450E+06 1.5352708E+06
-2.4382450E+06 1.5352708E+06-2.4382450E+06 1.5352708E+06
     31269       806-2.5239723E+06 1.5353111E+06
Segmentation fault (core dumped)
---- snap -----------------------------------------------
So I searched for the line which causes the core dump:
...
grep -n 31269 sp21_22/ROCK00.E00
29874:     31269       806-2.5239723E+06 1.5353111E+06
42988: 5.7757500E+04 9.5319818E+02        806      31269rocks
and I searched for the line containing "suchstr":
...
grep -n ROCK00.PAT sp21_22/ROCK00.E00
42177:ROCK00.PAT                      XX   5   5  26      1245
...
ls -l sp21_22/ROCK00.E00
-rw-r--r-x   1 eicksch  GFZ      2323977 Jul 11  2000 sp21_22/ROCK00.E00
...
If that's not possible, you could try to reduce the program to a
simple and as short as possible program that still shows the bug. In
this process, maybe you will find the cause of the problem in the
program, or reduce it to a short case that help us find and fix a
bug in GPC, if any.
If 60 lines are not too much: You will find an excerpt from the
source code - including declarations and the 20 lines around the
malicious code - at the end of mail.
...
You might also want to look at the chapter about BP in the GPC
manual.
I will have a look at it...
Stephan
-- 
----------------------------------------------------------------------
Stephan Eickschen                      Tel. :      +49 (0)8153 28-1351
GeoForschungsZentrum Potsdam (GFZ)     Fax. :      +49 (0)8153 28-1207
Division 1, Section 1.2
c/o                                    email:   eicksch@gfz-potsdam.de
DLR Oberpfaffenhofen                   www  : http://op.gfz-potsdam.de
Box 1116
82234 Wessling
Germany
----------------------------------------------------------------------

---- snip: source code ------------------------------------
program umwandlung_add(input,output);
const mmx = 500;
      nnx = 20000;
type extended = real;
     longint = integer;
     byte =integer;
     sss=string[255];
     ss12=string[12];
     pat = record
            b:boolean;
            r:byte;
            l:byte;
            n:string[15];
            g:integer;
           end;

var dat0,dat1,dat2,dat3,dat4,dat5:text;
    name1,suchstr,zeile,zeile2,info,zneu,zneu2,kopfz,kb,kbd3,zchui,infsrf:string[255];
    zs:string[400];
    reihe: array[1..mmx,1..nnx,1..5] of integer;
    rzaehler: array[1..mmx] of integer;
    hinfo,ginfo: array[1..15] of pat;
    i,j,k,k1,jl,jla,id,ls,nr,anzparam,lds,anzds,anzparama,ldsa,anzdsa:longint;
    ap,ep,lp,rp,anzdp,od,enddsnr,anzreihe,dsno,zint,ireihe,li,lj,lk,ll,lm:longint;
    x,y,z:extended;
    ch,chw:char;
    cod,realparam:integer;
    baat,bpat,btyp,bhgt,bdat,binf,bsht,bedt,bsrc,brev,bsrf:boolean;
    bnam,blat,blon,bnat:boolean;
    bar,bpe,bid,blen,bno,bap,bep,blp,brp,first,actlog,actlog2:boolean;

begin

{...}

writeln('Suche PAT');
{PAT finden}
   reset(dat4,kbd3+'/'+name1+'.E00');
   suchstr:=name1+'.PAT';
   ls:=length(suchstr);
writeln('suchstr = ', suchstr, ' ls = ',ls);
   repeat
    readln(dat4,zeile2);
writeln(zeile2);
    repeat
    if length(zeile2)<ls then readln(dat4,zeile2);
writeln(zeile2);
    until (length(zeile2)>(ls-1));
   until (substr(zeile2,1,ls)=suchstr);
writeln(suchstr, ' gefunden');
   readstr(trim(substr(zeile2,36,3)),anzparama);
   readstr(trim(substr(zeile2,44,3)),ldsa);
   readstr(trim(substr(zeile2,48,9)),anzdsa);
writeln(suchstr, ' gefunden, anzparama = ', anzparama, ', ldsa = ', ldsa, ', anzdsa = ', anzdsa, ' ... ');

{...}

end. {1}

---- snap: source code ------------------------------------

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Re: investigating a core dump...