#!/usr/bin/perl -w
#
#  fix_cap_bset.pl
# 
#  Sets the linux kernel varilble 'cap_bset' to 0xffffffff, so that 
#  root processes get CAP_SETPCAP. 
# 
#  This is designed for use with Linux v2.4 kernels, where the default
#  cap_bset is 0xfffffeff, i.e. everything except CAP_SETPCAP.
#
#  Copyright (c) 2002 Tim Deegan <tim.deegan@cl.cam.ac.uk>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#  $Id: fix_cap_bset.pl,v 1.2 2002/03/26 12:31:03 tjd21 Exp $
#

use strict;
use vars qw{ %matches @syms $sym };

sub fail() { print "$_[0]\n"; exit 1; }

%matches=();

open SYMS, "</proc/ksyms" or &fail ("can't read /proc/kysms");
while (<SYMS>) {
    next unless (/^([0-9a-f]+) (cap_bset\S*)\s*$/);
    $matches{"$2"} = $1;
}
close SYMS;

@syms = keys %matches;

if ($#syms < 0) { &fail ("can't find cap_bset in /proc/ksyms"); }
if ($#syms > 0) { print "Too many symbols: I see ";
		  foreach $sym (@syms) { print "$sym "; }
		  print "\n";
		  exit 1; }

exec 'kpoke', "0x$matches{$syms[0]}", '0xffffffff';

#
# EOF
#