2006-06-09 13:49:39 by steve

Added argument checking and documentation.

bin/xt-install-image

@@ -1,36 +1,134 @@
 #!/usr/bin/perl -w
 
-#
-#  Install Linux into a given directory, either via:
-#
-#    * debootstrap
-#    * rpmstrap
-#    * untarring.
-#    * copying
-#
+=head1 NAME
+
+ xt-install-image - Install a fresh copy of GNU/Linux into a directory
+
+=cut
+
+=head1 SYNOPSIS
+
+  xt-install-image [options]
+
+  Help Options:
+   --help     Show this scripts help information.
+   --manual   Read this scripts manual.
+   --version  Show the version number and exit.
+
+  Debugging Options:
+   --verbose  Be verbose in our execution.
+
+  Mandatory Options:
+   --location The location to use for the new installation
+   --dist     The name of the distribution which has been installed.
+
+  Exclusive Options:
+   --untar
+   --debootstrap
+   --rpmstrap
+   --copy
+
+  All other options from B<xen-create-image> will be passed as environmental
+ variables.
+
+=cut
+
+=head1 NOTES
+
+  This script is invoked by B<xen-create-image> after to create a new
+ distribution of Linux. 
+
+  There are several available methods of installation, depending upon the
+ users choice:
+
+  The command line arguments which are mandatory are:
+
+   --location  - The installation root to use.
+   --dist      - The distribution which is to be installed.
+
+  Once those mandatory arguments are parsed the installation method will
+ be selected.  This could be one of :
+
+* tar
+  Untar the given file.  Assume this contains a complete installation.
+
+* copy
+  Copy from the given directory.  Assume this contains a complete installation.
+
+* rpmstrap
+  Install using rpmstrap the named dist
+
+* debootstrap
+  Install using debootstrap the named dist.
+
+=cut
+
+
+=head1 AUTHOR
+
+ Steve
+ --
+ http://www.steve.org.uk/
+
+ $Id: xt-install-image,v 1.3 2006-06-09 13:49:39 steve Exp $
+
+=cut
+
+
+=head1 LICENSE
+
+Copyright (c) 2005-2006 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 Env;
+use Getopt::Long;
+use Pod::Usage;
 
 
 #
-#  Parse our arguments.
+#  Configuration values read from the command line.
 #
+#  We do not need to read any configuration file.
+#
+my %CONFIG;
+
+#
+# Release number.
+#
+my $RELEASE = '2.0';
 
 
 #
-#  Check arguments.
+#  Parse the command line arguments.
 #
+parseCommandLineArguments();
+
+
+#
+#  Check our arguments
+#
+checkArguments();
+
+
 
 #
 #  Work out how to install:
 #
-if ( $CONFIG{'debootstrap'} ) 
+if ( $CONFIG{'debootstrap'} )
 {
 }
 elsif ( $CONFIG{'rpmstrap'} )
 {
 }
-elsif ( $CONFIG{'copy-from'} )
+elsif ( $CONFIG{'copy'} )
 {
 }
 elsif ( $CONFIG{'untar'} )
@@ -45,10 +143,183 @@ else
 }
 
 
-#
-#  Finished
-#
 
 #
-#  Return 0 so that xen-create-image knows we succeeded.
+#  Exit cleanly - any errors which have already occurred will result
+# in "exit 1".
 #
+exit 0;
+
+
+
+=head2 parseArguments
+
+  Parse the command line arguments this script was given.
+
+=cut
+
+sub parseCommandLineArguments
+{
+    my $HELP	= 0;
+    my $MANUAL	= 0;
+    my $VERSION	= 0;
+
+    #
+    #  Parse options.
+    #
+    GetOptions(
+	       # Mandatory
+	       "location=s",     \$CONFIG{'location'},
+	       "dist=s",         \$CONFIG{'dist'},
+
+	       # Exclusive.
+	       "tar=s",          \$CONFIG{'tar'},
+	       "copy=s",         \$CONFIG{'copy'},
+	       "rpmstrap",       \$CONFIG{'rpmstrap'},
+	       "debootstrap",    \$CONFIG{'debootstrap'},
+
+	       # Help.
+	       "verbose",        \$CONFIG{'verbose'},
+	       "help",           \$HELP,
+	       "manual",         \$MANUAL,
+	       "version",        \$VERSION
+	      );
+
+    pod2usage(1) if $HELP;
+    pod2usage(-verbose => 2 ) if $MANUAL;
+
+
+    if ( $VERSION )
+    {
+	my $REVISION      = '$Revision: 1.3 $';
+
+	if ( $REVISION =~ /1.([0-9.]+) / )
+	{
+	    $REVISION = $1;
+	}
+
+	print "xt-install-image release $RELEASE - CVS: $REVISION\n";
+	exit;
+
+    }
+}
+
+
+
+=head2 checkArguments
+
+  Test that the command line arguments we were given make sense.
+
+=cut
+
+sub checkArguments
+{
+    #
+    #  We require a location.
+    #
+    if ( ! defined( $CONFIG{'location'} ) )
+    {
+	print "The '--location' argument is mandatory\n";
+	exit 1;
+    }
+
+
+    #
+    #  Test that the location we've been told contains
+    # a fresh installation of Linux exists
+    #
+    if ( ! -d $CONFIG{'location'} )
+    {
+	print "The installation directory we've been given doesn't exist\n";
+	print "We tried to use : $CONFIG{'location'}\n";
+	exit 1;
+    }
+
+
+    #
+    #  We require a distribution name.
+    #
+    if ( ! defined( $CONFIG{'dist'} ) )
+    {
+	print "The '--dist' argument is mandatory\n";
+	exit 1;
+    }
+
+
+    #
+    #  Test that the distribution name we've been given
+    # to configure has a collection of hook scripts.
+    #
+    #  If there are no scripts then we clearly cannot
+    # customise it!
+    #
+    my $dir = "/usr/lib/xen-tools/"  . $CONFIG{'dist'} .  ".d";
+
+    if ( ! -d $dir )
+    {
+	print <<E_OR;
+
+  We're trying to configure an installation of $CONFIG{'dist'} in
+ $CONFIG{'location'} - but there is no hook directory for us to use.
+
+  This means we won't know how to configure this installation.
+
+  We'd expect the hook directory to be : $dir
+
+  Aborting.
+E_OR
+	exit 1;
+    }
+
+
+    ##
+    # Now check the mutually distinct arguments
+    ##
+    my $count = 0;
+    foreach my $key ( qw(copy debootstrap rpmstrap tar ) )
+    {
+	if ( defined( $CONFIG{$key} ) )
+	{
+	    $count += 1;
+	}
+    }
+
+    #
+    # If count == 0 we had no recognised installation methods
+    #
+    if ( $count == 0 )
+    {
+	print <<EOF;
+ You did not specify an installation method.
+
+ One of the following must be given.  (Run "xt-install-image --manual" for details)
+
+   --copy
+   --debootstrap
+   --rpmstrap
+   --tar
+
+ Aborting.
+EOF
+
+        exit 1;
+    }
+    elsif ( $count > 1 )
+    {
+	print <<EOF;
+ You specify multiple installation methods.
+
+ Only one of the following must be given:
+
+   --copy
+   --debootstrap
+   --rpmstrap
+   --tar
+
+ Aborting.
+EOF
+	exit 1;
+    }
+
+}
+