#!/usr/bin/perl -w

#    make_debian-X11 Copyright (C) 2001 from gBootRoot
#    Lead Developer and Project Coordinator
#    Jonathan Rosenbaum <freesource@users.sourceforge.net>
#
#    http://gbootroot.sourceforge.net

#    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.

use strict;
use File::Basename;

# You will need to get swim at http://www.sourceforge.net/projects/avd
my $home = "$ENV{HOME}/.gbootroot";
my $home_yard = "$home/yard";
my $template_dir = "$home_yard/templates/";
my $home_yard_replacements = "$home_yard/Replacements";
my $nodename = `uname -n`; chomp $nodename;
my $debian_yard = "Debian-X11.yard";
my $status = "/var/lib/dpkg/status";
my $info = "/var/lib/dpkg/info";
my (%alternatives, @alternatives); # for checking for alternatives
my %inetd; # checks for inetd binaries.
my $version  = "1.0";

# You need file-rc, and you may add other extra stuff.  These packages were
# chosen for woody, so you may need something different.  If you add stuff, 
# check for dependencies, empty directories and special configuration files
# created by the package scripts.
#
# You may have to edit the text below STUFF.
#
# Swim provides excellent information for this task.  swim -qT packagename(s) &
# swim -ql --df packagename(s) & swim -qc packagename(s) (not all conf files 
# can  be found this way .. read above) so you will want to use 
# swim -q --scripts packagename(s) or 
# swim -q --preinst --postinst packagenames(s).

my @extra_packages = qw(file-rc swim apt apt-utils debconf nvi sysklogd
klogd netbase tcpd net-tools portmap netkit-ping netkit-inetd ifupdown less 
perl perl-modules libwrap0 ipchains whiptail libnewt0 libpopt0 debconf-utils
binutils bzip2 file libbz2-1.0 libfreetype6 libglib1.2 libgtk-perl 
libgtk1.2 make xfonts-base xfree86-common xlibmesa3 xlibs 
xserver-common xterm xutils zlib1g libgdbmg1 libxaw7 gbootroot
flwm libfltk1 xnest make-debian-x11 ash); 

# --------------------------------------------------------------------
# DIRECTIONS
# This creates a X11 filesystem.
# These replacements are unique and not found in CVS:
# add sources.list to this, too.

#/usr/X11R6/bin/startx <= Replacements/usr/X11R6/bin/startx-debian-X11 
#/root/README <= Replacements/root/README-debian-X11
#/root/make_swapfile <= Replacements/root/make_swapfile
#/root/umlnet <= Replacements/root/umlnet .. won't use.
#/etc/apt/sources.list  <= Replacements/etc/sources.list .. for adm.

# setup script does this
# 0. run dpkg-reconfigure for xfree86-common and xserver-common.
#    This catches mistakes.
# 1. dpkg-reconfigure for xfonts-base
# 2. make permissions correct for directory /home/user and all files * & .*.
# 3. run swim --initdb .. this is done by make-debian-x11.
# 4. run /etc/cron.daily/find
# ...................................................................
# debian_x11 sourceforge release preparation
# 5.  Other packages may be installed with apt-get.
# 6.  If any of these things were used: Clean out sources.list, 
#     /var/cache/archives /var/lib/apt/lists, /etc/network/interface 
#     should be commented in again. 
# 7.  remove linux uml_* or just leave them. 
# 8.  run /etc/cron.daily/sysklogd & /etc/cron.weekly/sysklogd
#     and clean out *.0, and dmesg if it needs it.
# 9.  halt and mount filesystem on loop and remove .bash_history if you 
#     want to.
# 10. test again.
# --------------------------------------------------------------------

# Before starting make sure swim and file-rc are present.
start_up();

system "swim --search \"Priority: required\" --no";
my $swim_packages = "swim -qS|";
my $swim_list = "swim -qSl|"; # Not using --df for empty directories.
$, = " ";
my $extra_files = "swim -ql @extra_packages|"; # Not using --df.
$, = "";

# All the packages
open(SWIM,$swim_packages) or die "Couldn't open swim_packages: $?\n";
my @required_packages = <SWIM>; chomp @required_packages;
close(SWIM);

# All the files
open(SWIM,$swim_list) or die "Couldn't open swim_list: $!\n";
my @required_files = <SWIM>; chomp @required_files;
close(SWIM);

open(SWIM,$extra_files) or die "Couldn't open extra_files: $!\n";
my @extra_files = <SWIM>; chomp @extra_files;
close(SWIM);

push(@required_files,@extra_files);


#################################################################
#################################################################
#           
#     EDIT
#     BELOW 
#  
# Edit below $stuff = << "STUFF" to make changes to the template. 
sub stuff {

my $stuff = << "STUFF";
# Generated by make_debian-X11.

# This template creates a complete Debian system which is more streamlined 
# than the base.tgz used for normal installations with the addition of X11.  
# Once everything is made, you can use user-mode-linux and apt to tweak the 
# system. Make-debian generates all the information you need.  You will need 
# swim and  file-rc installed, and you will have to be running a Debian 
# system to make this template.  Make_debian ditches info, man, and doc files 
# by default and timezone info not found on the host system, but gives you 
# the choice to decide otherwise.  

# Characteristics:  user: root passwd: root 
#                   user: user passwd: user
#                   Uses devfs.
    
# IMPORTANT NOTE:  Things slow down noticeably when the buffer gets too big in
# the verbosity box so consider closing it with the slider for faster 
# generation.  Look at /tmp/gbootroot_tmp'time-date'/verbose instead.
#
# The windows will appear to freeze up while using this template, this is 
# natural, be patient, because it will complete.  If you want to create 
# another filesystem concurrently, open up another invocation of gBootRoot.

# Todays Quote: Creating a root filesystem is all about stuff.

# The STUFF NEEDED in order for init to work.
/etc/runlevel.conf <=  Replacements/etc/runlevel.conf_debian-X11 # made by make_debian-X11
/etc/init.d/rc
/etc/init.d/rcS
/etc/inittab <= Replacements/etc/inittab.debian # specific to devfs
/etc/default/rcS

# Stuff needed to return init to its state prior to installing file-rc.
/etc/init.d/rc.links
/etc/init.d/rcS.links 
/usr/sbin/update-rc.d.links

# Login stuff 
/etc/securetty <= Replacements/etc/securetty.debian # devfs needs this
/root/.bashrc <= Replacements/root/.bashrc.debian
/root/.profile <= Replacements/root/.profile.debian
/home/user/.bashrc <= Replacements/home/user/.bashrc.debian
/home/user/.bash_profile <= Replacements/home/user/.bash_profile.debian
#/home/user/README <= Replacements/home/user/README # permissions issue
/etc/hostname <= Replacements/etc/hostname
/etc/motd <= Replacements/etc/motd

# Important stuff  .. you will need to edit the login files if you add packages
# which require other users/groups.  The default fstab mounts /dev/ubd/0.
#/etc/fstab <=  Replacements/etc/fstab.new # Made from Yard Box menu
/etc/fstab <=  Replacements/etc/fstab.debian # devfs specific
/etc/passwd <= Replacements/etc/passwd.debian
/etc/passwd- <= Replacements/etc/passwd-debian
/etc/group <= Replacements/etc/group.debian
/etc/group- <= Replacements/etc/group-debian
/etc/shadow <= Replacements/etc/shadow.debian

# The stuff required by dpkg.
/var/lib/dpkg/diversions <= Replacements/var/lib/dpkg/diversions_debian-X11
/var/lib/dpkg/cmethopt
/var/lib/dpkg/lock
/var/lib/dpkg/status <=  Replacements/var/lib/dpkg/status_debian-X11
/var/lib/dpkg/methods/disk
/var/lib/dpkg/methods/floppy
/var/lib/dpkg/methods/mnt
/var/lib/dpkg/info
/var/lib/dpkg/updates
/var/lib/dpkg/alternatives
/var/lib/dpkg/available <= Replacements/var/lib/dpkg/available

# Stuff needed by apt.
/var/cache/apt/archives/lock
/var/cache/apt/archives/partial
/var/lib/apt/lists/lock
/var/lib/apt/lists/partial
/etc/apt/*

# Timezone data from libc6
/usr/share/zoneinfo/localtime

# Debconf stuff
/var/cache/debconf

# Ipchains stuff
/etc/default/ipchains

# Netkit-inetd stuff
/etc/inetd.conf <= Replacements/etc/inetd.conf_debian-X11

# Tcpd stuff
/etc/hosts.allow
/etc/hosts.deny

# Network stuff
# You will want to edit the interfaces file.
# Remember to load any needed modules on the host system, for instance
# if tap is used, you will want to do this:
# modprobe ethertap
# modprobe netlink_dev
# And when you start your creation with the uml box you will want to add
# something like this to the options where HWaddr (see ifconfig) belongs
# to your network device:
# eth0=ethertap,tap0,HWaddr,192.168.1.5
/etc/resolv.conf 
/etc/hosts <= Replacements/etc/hosts
#/root/umlnet <= Replacements/root/umlnet # Example network setup script
/etc/networks <= Replacements/etc/networks
/etc/network/if-down.d      # empty
/etc/network/if-post-down.d # ""
/etc/network/if-pre-up.d    # ""
/etc/network/if-up.d        # ""
/etc/network/interfaces <= Replacements/etc/network/interfaces
/etc/network/options
/etc/network/spoof-protect

# X stuff
/usr/X11R6/bin/xsetroot
/usr/X11R6/bin/startx <= Replacements/usr/X11R6/bin/startx-debian-X11 
/root/README <= Replacements/root/README-debian-X11
/usr/bin/X11 -> ../X11R6/bin
/usr/include/X11 -> ../X11R6/include/X11 
/usr/lib/X11 -> ../X11R6/lib/X11
/usr/X11R6/lib/X11/rgb.txt -> /etc/X11/rgb.txt
/usr/bin/X11/xsetroot
/usr/X11R6/lib/X11/xserver -> /etc/X11/xserver
/etc/X11/Xwrapper.config
/etc/X11/xkb/xkbcomp -> /usr/X11R6/bin/xkbcomp
/usr/X11R6/bin/xkbcomp

# Administrative stuff
/root/make_swapfile <= Replacements/root/make_swapfile
/root/setup <= Replacements/root/setup-debian-X11
/root/README <= Replacements/root/README-debian-X11

# Devices - optional stuff which can be picked up by devfsd.
/dev/MAKEDEV # a link
/dev/mem	
/dev/kmem
/dev/null       
/dev/zero
/dev/ram*
/dev/console
/dev/tty[0-9]
/dev/hd[abcd]*              
/dev/ttyS[0-9]		    
/dev/fd0*                   
/dev/sd*                    
#/dev/cdrom 
#/dev/modem       
/dev/pts*
/dev/ptmx
/dev/initctl
/dev/urandom
/dev/ubd0 <= Replacements/dev/ubd0

#  Empty directories with no stuff.
/mnt        
/proc               
/tmp                
/var/tmp
/var/run
/var/lock
/var/log/news
/var/lib/locate
/var/backups

# Stuff so ldconfig creates all the proper dependencies.
/etc/ld.so.conf <= Replacements/etc/ld.so.conf

## ALL the REQUIRED files generated by make-debian.
## This is stuff from the required packages, so some files may be
## removed, or some files can be replaced with stuff from say .. busybox.
STUFF

return $stuff;
} # end sub stuff
#################################################################
#################################################################

###################
## Package Check ##
###################
 
# Better tell the user what required and extra packages don't exist.

# It is 100% unlikely that a required package is missing because
# the information is taken directly from the system. But it is fun
# to test for anyways, weirder things have been known to happen.

my $required_packages_check = "swim -q @required_packages|";
open (CHECK,$required_packages_check) 
    or die "Couldn't find any required packages: $?\n";
my @rpc;
while (<CHECK>) {
    if (/^package/) {
        my $rpc = (split(/\s/))[1];
	push(@rpc,$rpc);

    }
}
close (CHECK);

if (@rpc) {
    print STDERR "These are the required packages which were specified:\n\n";
    $, = " ";
    print STDERR @required_packages, "\n\n";
    print STDERR "This is what wasn't installed on your system:\n\n";
    print STDERR @rpc , "\n\n";
    $, = "";
}

my $extra_packages_check = "swim -q @extra_packages|";
open (CHECK,$extra_packages_check) 
    or die "Couldn't find any required packages: $?\n";
my @epc;
while (<CHECK>) {
    if (/^package/) {
        my $epc = (split(/\s/))[1];
	push(@epc,$epc);
    }
}
close (CHECK);

if (@epc) {
    print STDERR "These are the extra packages which were specified:\n\n";
    $, = " ";
    print STDERR @extra_packages, "\n\n";
    print STDERR "This is what wasn't installed on your system:\n\n";
    # spooked myself
    #print STDERR "[If any of the package(s) below are already installed\n";
    #print STDERR " run 'swim --rebuilddb' and run make_debian-X11 again.]\n\n";
    print STDERR @epc , "\n\n";
    $, = "";
}

push(@required_packages,@extra_packages);


#######################
## Template Creation ##
#######################

# Ask some questions first.
my $doc_reply = "nothing";
print STDERR "The default is to remove /usr/share/{doc,man,info}? [yes or no]: ";
while (<STDIN>) {
    $doc_reply = $_;
    print $doc_reply;
    last if $doc_reply eq "yes\n";
    last if $doc_reply eq "no\n";
    if ($doc_reply eq "\n") { $doc_reply = "yes\n"; last; }
    if ($doc_reply ne "yes\n" || $doc_reply  ne "no\n") { 
	print  "The default is to remove /usr/share/{doc,man,info}? [yes or no]: ";
    }
}

print STDERR "\nThe default is to remove everything in /usr/share/zoneinfo\n" .
    "except for your local settings found in /etc/localtime? [yes or no]: ";
my $localtime_reply = "nothing";
while (<STDIN>) {
    $localtime_reply = $_;
    last if $localtime_reply eq "yes\n";
    last if $localtime_reply eq "no\n";
    if ($localtime_reply eq "\n") { $localtime_reply = "yes\n"; last; }
    if ($localtime_reply ne "yes\n" || $localtime_reply  ne "no\n") { 
	print  "The default is to remove everything in /usr/share/zoneinfo\n" .
	    "except for your local settings found in /etc/locatime? [yes or no]: ";
    }
}

open(DEBIAN,">$template_dir/$debian_yard") 
	or die "Couldn't open $template_dir$debian_yard: $!\n";
open(FILERC,"/etc/runlevel.conf") or die "No runlevel.conf: $!\n";
my @filerc = <FILERC>;
close(FILERC);

print DEBIAN stuff();

my @file_rc;
alternatives();
inetd_in();
foreach (@required_files) {
    if (-e && !-d) {
	if ($doc_reply eq "no\n") {
	    if ($alternatives{$_}) {
		push(@alternatives,$_);
	    }
	    if ($inetd{$_}) {
		$inetd{$_} = 1;
	    }
	    if ($localtime_reply eq "yes\n") {
		    print DEBIAN "$_\n" if ! m,/usr/share/zoneinfo,;
	    }
	    else {
		print DEBIAN "$_\n";
	    }
	}
	else {
	    if (! m,/usr/share/info|/usr/share/man|/usr/share/doc|/usr/X11R6/man,) {
		if ($alternatives{$_}) {
		    push(@alternatives,$_);
		}
		if ($inetd{$_}) {
		    $inetd{$_} = 1;
		}
		if ($localtime_reply eq "yes\n") {
		    print DEBIAN "$_\n" if ! m,/usr/share/zoneinfo,;
		}
		else {
		    print DEBIAN "$_\n";
		}
	    }
	}
	if (m,/etc/init\.d,) {
	    foreach my $filerc (@filerc) {
		     push(@file_rc,$filerc) if $filerc =~ /$_/;		
	    }
	}		   
    }
}
inetd_out();

print DEBIAN "\n# Scripts associated with packages found in info/*\n";
print DEBIAN status_info_divert();

# alternatives
print DEBIAN "\n# Alternative stuff.\n";
foreach (@alternatives) {
    if ($alternatives{$_}) {
	foreach my $alt ( 0 .. $#{ $alternatives{$_} } ) {
	    print DEBIAN "/etc/alternatives/", 
	    $alternatives{$_}[$alt], "\n";
	    print DEBIAN "/var/lib/dpkg/alternatives/", 
	    $alternatives{$_}[$alt], "\n";
	    print DEBIAN dirname($_), "/", 
	    $alternatives{$_}[$alt], "\n";
	}
    }
}

close(DEBIAN);
system "chmod 444 $template_dir/$debian_yard"; # A good idea
print STDERR "\nAll finished making your $debian_yard template.\n";

#########################
# END TEMPLATE CREATION #
#########################

# This creates a tweaked runlevel.conf which is easier then trying to figure
# out which symlinks to use in /etc/rc?d.

open(MY_FILERC,">$home_yard_replacements/etc/runlevel.conf_debian-X11") 
    or die "Couldn't open $home_yard_replacements/etc/runlevel.conf_debian-X11: $!\n"; 
my @sortedrc = map { $_->[1] }
sort { $a->[0] <=> $b->[0] }
map { [ (split(/\s/,$_))[0], $_ ] }
@file_rc;
print MY_FILERC @sortedrc;
close(MY_FILERC);

# This creates a status file for use by dpkg and swim.
# Although swim could be used to do this, it is more efficient just to
# parse the status file.  But because this is a good exercise for
# using this script to create a status file found from packages on a system 
# which doesn't actually have a status file .. here would be the order 
# needed when using swim to query:
#
# Package, Status, Priority, Section, Installed-Size, Maintainer, Source, 
# Version, Replaces, Provides, Depends, Pre-Depends, Recommends, Suggests,
# Conflicts, Conffiles, Description.
#
# Conffiles would have to be handled both before and after Root Filesystem
# creation so that their md5sums could be accounted for in status.
#
# And this finds all the scripts associated with a package in info/*,
# creates an empty available file, and creates the diversions file.

sub status_info_divert {

$/ = "";
open(STATUS,"$status") or die "Can't find /var/lib/dpkg/status: $!\n";
home_builder("$home_yard_replacements/var/lib/dpkg");
system "touch $home_yard_replacements/var/lib/dpkg/available";
    #or die "Couldn't create Replacements/var/lib/dpkg/available: $!\n";
open(NEW_STATUS,">$home_yard_replacements/var/lib/dpkg/status_debian-X11")
    or die "Couldn't open Replacements/var/lib/dpkg/status_debian-X11: $!\n";
while (<STATUS>) { # keep the order
    my $stat = $_;
    my $stat2 = (split(/\n/,$stat))[0]; # might as well
    foreach my $rp (@required_packages) {
	$rp = (split(/_/,$rp))[0];
	# Deal with names with +
	$rp =~ s/\+/\\+/g if $rp !~ /\\+/g;
	if ($stat2 =~ /^Package: $rp$/) {
	    # For debian packaging
	    if ($rp eq "make-debian-x11") {
		if ($stat =~ /unpacked/) {
		    $stat =~ s/unpacked/installed/;
		}
		print NEW_STATUS $stat;
            }
            else {
		print NEW_STATUS $stat;
	    }
	} 
    }
}
close(NEW_STATUS);
close(STATUS);
$/ = "\n";

my %dpkg_divert;
my $dpkg_divert = "dpkg-divert --list|";
open(DIVERT,"$dpkg_divert") 
    or die "Couldn't find the dpkg-divert command: $!\n";
while (<DIVERT>) {
    
    my($original,$diversion,$package) = (split(" "))[2,4,6];
    chomp $package;
    if (!$dpkg_divert{$package}) { # Just add to the array
	$dpkg_divert{$package} = [$original,$diversion];	
    }
    else {
	push @{ $dpkg_divert {$package} }, $original, $diversion;
    }

}
close(DIVERT) or die "Couldn't close: $!\n";

open(DIVERT,">$home_yard_replacements/var/lib/dpkg/diversions_debian-X11")
    or die "Couldn't open Replacements/var/lib/dpkg/diversions_debian-X11: $!\n";
my @info;
foreach my $rp (@required_packages) {
    $rp = (split(/_/,$rp))[0];
    # Get rid of the escapes from the previous invocation.
    $rp =~ s/\\//g if $rp =~ /\\+/g;

    my $count = 0; my @divert;
    if ($dpkg_divert{$rp}) {
            foreach my $dv ( @{ $dpkg_divert{$rp} } ) {
		push(@divert,$dv);
		if ($count == 1) {
		    print DIVERT "$divert[0]\n";
		    print DIVERT "$divert[1]\n";
		    print DIVERT "$rp\n";
		    $count = -1; undef @divert;
		}
		$count++;
            }
    }

    # Figure out info/*  .. this covers it for now.
    if (-f "$info/$rp.preinst") {
	push(@info,"$info/$rp.preinst\n");
    }
    if (-f "$info/$rp.postinst") {
	push(@info,"$info/$rp.postinst\n");        
    }
    if (-f "$info/$rp.prerm") {
	push(@info,"$info/$rp.prerm\n");        
    }
    if (-f "$info/$rp.postrm") {
	push(@info,"$info/$rp.postrm\n");        
    }
    if (-f "$info/$rp.list") {
	push(@info,"$info/$rp.list\n");        
    }
    if (-f "$info/$rp.shlibs") {
	push(@info,"$info/$rp.shlibs\n");        
    }
    if (-f "$info/$rp.conffiles") {
	push(@info,"$info/$rp.conffiles\n");        
    }
    if (-f "$info/$rp.md5sums") {
	push(@info,"$info/$rp.md5sums\n");        
    }
    if (-f "$info/$rp.config") {
	push(@info,"$info/$rp.config\n");        
    }
    if (-f "$info/$rp.templates") {
	push(@info,"$info/$rp.templates\n");        
    }

}
close(DIVERT);

return @info;

} # end sub status_info_divert

sub alternatives {

    my $ls = "ls -l /etc/alternatives|";
    my @ls;
    open(LS,$ls) or die "No ls?: $!\n";
    while (<LS>) {
	if (/->/) {
	    my($left,$right) = split(" -> ");
	    chomp $right; 
	    # Yard adds this stuff.
	    $right =~ s/\.\.\/\.\.//g; 

	    $left =~ s/^.*\d+\s//g;
	    if (!$alternatives{$right}) {
		$alternatives{$right} = [$left]; 
	    }
	    else {
		push @{ $alternatives {$right} }, $left;
	    }
	}
    }
    close(LS);

} # end sub alternatives

sub inetd_in {
    
    my $inetd = "/etc/inetd.conf";
    open(INETD,"$inetd") or return "Couldn't open /etc/inetd.conf: $!\n";
    # Basically will ignore anything with less than 7 columns, and
    # will comment lines where the executables don't exist.
    while (<INETD>) {
	if ( (split(/\s+/))[6] && !/^#.*/ ) {
	     my $seventh_column = (split(/\s+/))[6]; 
	     chomp $seventh_column;
	     $inetd{ basename($seventh_column) } = 0;
	 }
    }
    close(INETD);

}

sub inetd_out {

    my $inetd = "/etc/inetd.conf";
    open(REP_INETD,">$home_yard_replacements/etc/inetd.conf_debian-X11") 
	or return "Couldn't open Replacements/etc/inetd.conf_debian-X11: $!\n";
    open(INETD,"$inetd") or return "Couldn't open /etc/inetd.conf: $!\n";
    while (<INETD>) {
	if ( (split(/\s+/))[6] && !/^#.*/ ) {
	     my $seventh_column = (split(/\s+/))[6]; 
	     chomp $seventh_column;
	     if ( $inetd{ basename($seventh_column) } == 1 ) {
		 print REP_INETD $_;
	     }
	     else {
		 print REP_INETD "# $_";
	     }
	}
	else {
	    print REP_INETD $_;
	}
    }
    close(REP_INETD);
    close(INETD);

}

sub home_builder {

    my ($home_builder) = @_; 

    if (!-d $home_builder) {
	if (-e $home_builder) {
	    print "ERROR: A file exists where $home_builder should be.\n";
	}	
	else {
	    my @directory_parts = split(m,/,,$home_builder);
	    my $placement = "/";
	    for (1 .. $#directory_parts) {
		$_ == 1 ? ($placement = "/$directory_parts[$_]")
		    : ($placement = $placement . "/" . $directory_parts[$_]);
		-d $placement or mkdir $placement;
	    }
	}
    }

} # end home_builder

# The least important function,
# so therefore probably the most important function.
sub start_up {

    # existence of dpkg
    if (!-f "/usr/bin/dpkg") {
	die "You are not using a Debian system, in the future this " .
	   "may be supported, but for now you need living Debian.\n";
    }

    # Swim has never been installed before?
    my $dpkg_result = system "dpkg -l swim >/dev/null 2>&1";
    if ($dpkg_result !=0) {
	die "Swim is required:\n\n" .
            "Add one of these lines to your /etc/apt/sources.list:\n" .
	    "deb http://prdownloads.sourceforge.net/avd ./  or\n" .
	    "deb http://download.sourceforge.net/avd ./\n\n" .
            "Then do `apt-get update` and `apt-get install swim`\n" .
            "";
    }

    # Swim has been installed but is removed or purged
    my $dpkg_s = "dpkg -s swim|";
    open(DPKG,"$dpkg_s") or die "Couldn't find dpkg: $!\n";
    while (<DPKG>) {
	if (/Status:/) {
	    if (!/\s+installed/) {
		if (/purge|deinstall/) {
		    die "Swim needs to be reinstalled:\n\n" .
	       "Add one of these lines to your /etc/apt/sources.list:\n" .
	       "deb http://prdownloads.sourceforge.net/avd ./  or\n" .
	       "deb http://download.sourceforge.net/avd ./\n\n" .
	       "Then do `apt-get update` and `apt-get install swim`\n" .
            "";
		}
	    }
	}
    }
    close(DPKG);

    # Swim is installed but the databases need to be initialized.
    my $swim = "swim -qf /sbin/init|";
    open(SWIM,$swim) or die "Had trouble using swim: $!\n";
	while (<SWIM>) {
	    if ($_ eq "file init is not owned by any package\n") {
		my $db_reply = "nothing";
		print STDERR "It appears that swim has never had its database " .
		    "generated.  Would you like me to do this for you? " .
			"[yes or no]: ";
		while (<STDIN>) {
		    $db_reply = $_;
		    last if $db_reply eq "yes\n";
		    last if $db_reply eq "no\n";
		    if ($db_reply ne "yes\n" || $db_reply  ne "no\n") { 
		print "It appears that swim has never had its database " .
		    "generated.  Would you like me to do this for you? " .
			"[yes or no]: ";
		    }
		}
		system "swim --initdb" if $db_reply eq "yes\n";
		die "Sorry, can't continue until database is " .
		    "generated\n" if $db_reply eq "no\n";
	    }
	}
    close(SWIM);

    # Does file-rc exit?
    $dpkg_s = "dpkg -s file-rc|";
    open(DPKG,"$dpkg_s") or die "Couldn't find dpkg: $!\n";
    while (<DPKG>) {
	if (/Status:/) {
	    if (!/\s+installed/) {
	    die "The script requires that file-rc be installed. " .
		"Please install it first.\n";
	    }
	}
    }
    close(DPKG);

    if (!-d $home) {
	home_builder($template_dir);
	home_builder("$home_yard_replacements/etc");
    }

    print STDERR "Everything is in order, but it never hurts to rebuild swim "
	. "with --rebuilddb if you haven't done it in awhile\n";


} # end start_up