#!/usr/bin/perl -w

=head1 NAME

xen-delete-image - Delete previously created Xen instances.

=head1 SYNOPSIS

  xen-delete-image [options] imageName1 imageName2 ... imageNameN  

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

  General options:
   --dir      Specify the output directory where images were previously saved.

  Testing options:
   --test     Don't complain if we're not invoked by root.

=cut


=head1 OPTIONS

=over 8

=item B<--dir>
Specify the output directory where images were previously saved.

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

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

=item B<--test>
Don not complain, or exit, if the script is not executed by the root user.

=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
 Xen instances which have previously been created.

  You must be root to run this script as it removes the Xen configuration
 file from /etc/xen.  (When invoked with the '--test' flag the script will
 continue running, but will fail to remove anything which the user does
 not have permission to delete.)

=cut


=head1 EXAMPLES

  Assuming that you have three images 'foo', 'bar', and 'baz', stored
 beneath /home/xen the first two may be deleted via:

    xen-delete-image --dir=/home/xen foo bar

=cut


=head1 AUTHOR

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

 $Id: xen-delete-image,v 1.22 2006-02-05 13:38:49 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 file.
#
my %CONFIG;

#
# Release number.
#
my $RELEASE = '0.9';




#
# Read the global configuration file if it exists.
#
if ( -e "/etc/xen-tools/xen-tools.conf" )
{
    readConfigurationFile( "/etc/xen-tools/xen-tools.conf" );
}


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


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

  This script is not running with root privileges, so the configuration
 file(s) beneath /etc/xen will not be removed.

E_O_ROOT

    exit;
}


#
#  Loop over the supplied arguments, and attempt to delete each
# image.
#
while( my $name = shift )
{
    deleteXenImage( $name );
}


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


    if ( $VERSION )
    {
	my $REVISION      = '$Revision: 1.22 $';

	if ( $REVISION =~ /1.([0-9.]+) / )
	{
	    $REVISION = $1;
	}

	print "xen-delete-image release $RELEASE - CVS: $REVISION\n";
	exit;

    }
}



=head2 deleteXenImage

  Delete the named image, and the corresponding configuration file
 from /etc/xen.

=cut

sub deleteXenImage
{
    my ($hostname) = ( @_ );

    #
    #  Delete the configuration file.
    #
    if ( -e "/etc/xen/" . $hostname . ".cfg" )
    {
	unlink( "/etc/xen/" . $hostname . ".cfg" );
    }


    #
    #  Now the swap image
    #
    if ( -e $CONFIG{'dir'} . "/domains/" . $hostname . "/swap.img" )
    { 
	unlink( $CONFIG{'dir'} . "/domains/" . $hostname . "/swap.img" );
    }

    #
    #  Now the disk image
    #
    if ( -e $CONFIG{'dir'} . "/domains/" . $hostname . "/disk.img" )
    { 
	unlink( $CONFIG{'dir'} . "/domains/" . $hostname . "/disk.img" );
    }


    #
    #  Now remove the directory.
    #
    if ( -d $CONFIG{'dir'} . "/domains/" . $hostname )
    {
	rmdir ( $CONFIG{'dir'} . "/domains/" . $hostname );
    }
}