Re: [PLUG] JDK 1.3 and RH7.1

[Kevin Brosius <kbrosius@kns.com>]

tom panzarella wrote:
> 
> 
> >  It could be
> > painful, but if you have to run RH7.1 then it should be possible to run
> > anything you want against a different set of libc libraries
> 
> Anyone know how to do this?
> 

Well, yeah...

Depends on what you're trying to run and how it fails.  A single app can
usually be run by using LD_PRELOAD (syntax at home on Linux, don't have
it in front of me) in front of the app with the library name.
(http://howto.tucows.com/LDP/HOWTO/GCC-HOWTO/x796.html has some comments
on how LD_PRELOAD and LD_LIBRARY_PATH work.)

You can often run an app linked against different libraries by modifying
LD_LIBRARY_PATH in the environment of the shell you run the app from. 
Netscape used to setenv LD_LIBRARY_PATH need this to switch out some
libraries.  You use it by placing the new library directory at the front
of the existing path, like:

setenv LD_LIBRARY_PATH /path/to/lib;${LD_LIBRARY_PATH}

Syntax for Solaris & tcsh, so modify for your shell, but Linux ld
recognizes LD_LIBRARY_PATH also.

(Caution - system risk ahead - for trial only, you shouldn't need to do
something like this if the distro already supplied compatibility
libraries)
If you've got boot disks made up, you can also try changing which
default libc your whole system uses to see if the app your trying to run
can be made to work at all.  Modify (back it up first!) /etc/ld.so.conf
to include your new (or older libs as the case may be) and re-run
ldconfig.  The order of directories specifies search order in
ld.so.conf.

This is helpful...
http://howto.tucows.com/man/man8/ldconfig.8.html

Just realize you may break existing apps if they can't run against the
new library setup listed in ld.so.conf.  That's why you want boot
disks.    And a copy of your old ld.so.conf.  Just use your boot disks,
restore ld.so.conf to the original, and reboot your system and you're
back to running again.

-- 
Kevin Brosius


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