#!/usr/bin/perl -w

=head1 NAME

xen-delete-image - Delete a previously created Xen instance.

=head1 SYNOPSIS

  xen-delete-image [options]

  Help Options:
   --help     Show help information.
   --manual   Read the manual for this script.
   --version  Show the version information and exit.

  General options:
   --dir       Specify where the output image was saved.
   --hostname  Set the images hostname.

=cut



=head1 OPTIONS

=over 8

=item B<--dir>
Specify the output directory image was saved.

=item B<--help>
Show help information.

=item B<--hostname>
Specify the name of the image to remove.

=item B<--manual>
Read the manual for this script.

=item B<--version>
Show the version number and exit.

=back

=cut


=head1 DESCRIPTION


  xen-delete-image is a simple script which allows you to delete
 a Xen instances which has previously been created with xen-create-image.

  You must be root to run this script as it removes the Xen configuration
 file from /etc/xen.


=cut


=head1 AUTHOR


 Steve
 --
 http://www.steve.org.uk/

 $Id: xen-delete-image,v 1.4 2005-12-21 19:26:05 steve Exp $

=cut


=head1 LICENSE

Copyright (c) 2005 by Steve Kemp.  All rights reserved.

This module is free software;
you can redistribute it and/or modify it under
the same terms as Perl itself.
The LICENSE file contains the full text of the license.

=cut


use strict;
use English;
use Getopt::Long;
use Pod::Usage;


#
#  Configuration options, initially read from the configuration files
# but may be overridden by the command line.
#
#  Command line flags *always* take precedence over the configuration files(s).
#
my %CONFIG;




#
#  Read configuration file(s) if they exist.
#
if ( -e "/etc/xen-tools/xen-tools.conf" )
{
    readConfigurationFile( "/etc/xen-tools/xen-tools.conf" );
}
if ( -e $ENV{'HOME'} . ".xen-tools.conf" )
{
    readConfigurationFile( $ENV{'HOME'} . ".xen-tools.conf" );
}


#
#  Parse command line arguments, these override the values from the
# configuration file.
#
parseCommandLineArguments();


#
#  Abort if non-root user.
#
if ( $EFFECTIVE_USER_ID != 0 )
{
    print <<E_O_ROOT;

  In order to use this script you must be running with root privileges.

  (This is necessary to remove the Xen configuration file beneath /etc/xen.)

E_O_ROOT

    exit;
}



#
#  Delete the configuration file.
#
if ( -e "/etc/xen/" . $CONFIG{'hostname'} . ".cfg" )
{
    unlink( "/etc/xen/" . $CONFIG{'hostname'} . ".cfg" );
}
else
{
    print "Xen configuration file not found ";
    print "/etc/xen/" . $CONFIG{'hostname'} . ".cfg" . "\n";
}


#
#  Now the swap
#
if ( -e $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/swap.img" )
{ 
    unlink( $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/swap.img" );
}
else
{
    print "Swap file not found : ";
    print  $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/swap.img\n";

}



#
#  Now the disk image
#
if ( -e $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/disk.img" )
{ 
    unlink( $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/disk.img" );
}
else
{
    print "Disk image file not found : ";
    print  $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "/disk.img\n";

}


#
#  Now remove the directory.
#
if ( -d $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} )
{
    rmdir ( $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} );
}
else
{
    print "Domain directory not found : ";
    print $CONFIG{'dir'} . "/domains/" . $CONFIG{'hostname'} . "\n";
}


#
#  All done.
#
exit;



=head2 readConfigurationFile

  Read the configuration file specified.

=cut

sub readConfigurationFile
{
    my ($file) = ( @_ );

    open( FILE, "<", $file ) or die "Cannot read file '$file' - $!";

    my $line       = ""; 

    while (defined($line = <FILE>) ) 
    {
        chomp $line;
	if ($line =~ s/\\$//) 
	{
	    $line .= <FILE>;
	    redo unless eof(FILE);
	}
      
	# Skip lines beginning with comments
	next if ( $line =~ /^([ \t]*)\#/ );

	# Skip blank lines
	next if ( length( $line ) < 1 );

	# Strip trailing comments.
	if ( $line =~ /(.*)\#(.*)/ )
	{
	    $line = $1;
	}

	# Find variable settings
	if ( $line =~ /([^=]+)=([^\n]+)/ )
	{
	    my $key = $1;
	    my $val = $2;

	    # Strip leading and trailing whitespace.
	    $key =~ s/^\s+//;
	    $key =~ s/\s+$//;
	    $val =~ s/^\s+//;
	    $val =~ s/\s+$//;
	    
	    # Store value.
	    $CONFIG{ $key } = $val;
	}
    }

    close( FILE );
}




=head2 parseCommandLineArguments

  Parse the arguments specified upon the command line.

=cut

sub parseCommandLineArguments
{
    my $HELP	= 0;
    my $MANUAL	= 0;
    my $VERSION	= 0;

    #  Parse options.
    #
    GetOptions(
	       "hostname=s", \$CONFIG{'hostname'},
	       "dir=s",      \$CONFIG{'dir'},
	       "help",       \$HELP,
	       "manual",     \$MANUAL,
	       "version",    \$VERSION
	      );
    
    pod2usage(1) if $HELP;
    pod2usage(-verbose => 2 ) if $MANUAL;


    if ( $VERSION )
    {
	my $REVISION      = '$Id: xen-delete-image,v 1.4 2005-12-21 19:26:05 steve Exp $';
	$VERSION = join (' ', (split (' ', $REVISION))[2]);
	$VERSION =~ s/,v\b//;
	$VERSION =~ s/(\S+)$/$1/;

	print "xen-delete-image release 0.5 - CVS: $VERSION\n";
	exit;

    }
}