Reproductable Segmentation Fault

Mon, 24 Jun 2002 10:47:32 -0700 

Hello.

First, my configuration (i snipped as much as possible).


DocumentRoot /home/nikratio/Projekte/www-testing

   <Perl>
   use lib '/home/nikratio/Projekte/www-testing/lib';
   </Perl>
   
   #PerlRequire "debug.pl"
   PerlModule CGI
   PerlModule Apache::Registry
   PerlModule SSIChainNG


<Directory /home/nikratio/Projekte/www-testing>
        Options Includes Indexes ExecCGI
        <Files *.pl>
            SetHandler perl-script
            PerlSendHeader On
            PerlHandler SSIChainNG Apache::Registry
        </Files>
        <Files minitest.pl>
 #          PerlFixupHandler Apache::DB
        </Files>
        AddHandler server-parsed .shtml      
        Order deny,allow
        Allow from all  
        AllowOverride None
</Directory>

Attachment: msg28533/pl00000.pl
Description: Test script

Attachment: msg28533/pl00001.pl
Description: support file 1

Include File 2

Attachment: msg28533/pl00002.pl
Description: Custom module 1

Attachment: msg28533/pl00003.pl
Description: Custom module 2


So far so good. Here are the versions:

Apache/1.3.24 (Unix) Debian GNU/Linux mod_perl/1.26 PHP/4.2.1 mod_fastcgi/2.2.10 
mod_ssl/2.8.7 OpenSSL/0.9.6c mod_jk/1.1.0


Summary of my perl5 (revision 5.0 version 6 subversion 1) configuration:
  Platform:
    osname=linux, osvers=2.4.13, archname=i386-linux
    uname='linux duende 2.4.13 #1 wed oct 31 19:18:07 est 2001 i686 unknown '
    config_args='-Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=i386-linux 
-Dprefix=/usr -Dprivlib=/usr/share/perl/5.6.1 -Darchlib=/usr/lib/perl/5.6.1 
-Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 
-Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.6.1 
-Dsitearch=/usr/local/lib/perl/5.6.1 -Dman1dir=/usr/share/man/man1 
-Dman3dir=/usr/share/man/man3 -Dman1ext=1 -Dman3ext=3perl 
-Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Duseshrplib 
-Dlibperl=libperl.so.5.6.1 -Dd_dosuid -des'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
  Compiler:
    cc='cc', ccflags ='-DDEBIAN -fno-strict-aliasing -I/usr/local/include 
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-DDEBIAN -fno-strict-aliasing -I/usr/local/include'
    ccversion='', gccversion='2.95.4  (Debian prerelease)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lgdbm -ldb -ldl -lm -lc -lcrypt
    perllibs=-ldl -lm -lc -lcrypt
    libc=/lib/libc-2.2.4.so, so=so, useshrplib=true, libperl=libperl.so.5.6.1
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: USE_LARGE_FILES
  Built under linux
  Compiled at Jan 11 2002 04:09:18
  @INC:
    /usr/local/lib/perl/5.6.1
    /usr/local/share/perl/5.6.1
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.6.1
    /usr/share/perl/5.6.1
    /usr/local/lib/site_perl
    .



Basically, SSIParser is a Subclass of Apache::SSI. It parses text for
SSI commands and executes them. It waqs modified to call a special
method instead of printing to STDOUT, which would cause loops.

SSIChainNG is a Subclass of Apache::OutputChain. It ties STDOUT to
itself and searches all received data for SSI tags using SSI parser.

minitest.pl causes a segfault on execution:

,----
| [Mon Jun 24 19:35:09 2002] [notice] child pid 4575 exit signal
| Segmentation fault (11)
`----

I couldn't solve this problem. But here are my various attempts to
track the bug:


1. Joining the two print commands into one avoids the segfault:

,----
| print(header(),
|       start_html(),
|       '<!--#include virtual="t1.pl"-->',
|       h1("Main file").
|       '<!--#include virtual="t2.html"-->',
|       end_html);
`----

(painless execution).


2. tied *STDOUT refers to an other object after the first print
   commmand.

3. Debugging session

4. Ah, the sub-request invoiced by Apache::SSI ties *STDOUT also.
   Therefore it is tied to the wrong request object after execution of
   the sub request. But protecting STDOUT with local(*STDOUT) during
   the sub request doesn't help.


 Any ideas to fix the problem?  

 Thanks,
 
   --Nikolaus

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