2007-03-11 15:40:58 by steve

Allow last octet of each IP address to be dynamically determined.
  This allows :

  "--ip=192.168.1" to be specified and the last octet will automatically
 increment for each invokation.

bin/xen-create-image

@@ -504,7 +504,7 @@ Install an X11 server, using VNC and XDM
  --
  http://www.steve.org.uk/
 
- $Id: xen-create-image,v 1.134 2007-02-26 14:48:36 steve Exp $
+ $Id: xen-create-image,v 1.135 2007-03-11 15:40:58 steve Exp $
 
 =cut
 
@@ -945,6 +945,7 @@ sub setupDefaultOptions
     $CONFIG{'pid'}         = 0;
     $CONFIG{'template'}    = '';
     $CONFIG{'roledir'}     = '/etc/xen-tools/role.d';
+    $CONFIG{'ipfile'}      = '/etc/xen-tools/ips.txt';
 
     #
     #  Installation method defaults to "debootstrap".
@@ -1141,7 +1142,7 @@ sub parseCommandLineArguments
 
     if ( $VERSION )
     {
-        my $REVISION      = '$Revision: 1.134 $';
+        my $REVISION      = '$Revision: 1.135 $';
         if ( $REVISION =~ /1.([0-9.]+) / )
         {
             $REVISION = $1;
@@ -2324,7 +2325,29 @@ sub runCustomisationHooks
 
     foreach my $i ( @$ips )
     {
+        #
+        #  Here we have special handling for the case where
+        # IP addresses are xx.yy.zz - we automatically add
+        # in the next octet using /etc/xen-tools/ips.txt
+        #
+        #
+        if ( $i =~ /^([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)$/ )
+        {
+            # NOP
+            $CONFIG{'verbose'} && logprint( "IP address is complete: $i\n" );
+        }
+        elsif ( $i =~ /^([0-9]+)\.([0-9]+)\.([0-9]+)$/ )
+        {
+            $CONFIG{'verbose'} &&
+              logprint( "Automatically determining the last octet for $i\n" );
+
+            $i = findNextIP( $i );
+
+            $CONFIG{'verbose'} && logprint( "Found $i\n" );
+        }
+
         $ENV{'ip' . $count } = $i;
+
         $count += 1;
     }
     $ENV{'ip_count'} = ($count - 1);
@@ -2360,6 +2383,44 @@ sub runCustomisationHooks
 
 
 
+=begin doc
+
+  Find the next usable IP address for the given host.
+
+  This works by reading the last octet from a global file, incrementing
+ it and writing it back to the file.  So we have a running total of the
+ last IP.
+
+=cut
+
+sub findNextIP
+{
+    my( $ip ) = (@_);
+
+    # Abort if we don't have the IP file.
+    return $ip if ( ! -e $CONFIG{'ipfile'} );
+
+    # Read the number.
+    open( OCTET, "<", $CONFIG{'ipfile'} ) or return $ip;
+    my $line = <OCTET>;
+    $line = 1 if ( ( ! defined( $line ) ) || ( $line !~ /^([0-9]+)$/ ) );
+    close( OCTET );
+    chomp( $line );
+
+    # Add it
+    $ip .= ".$line";
+
+    # Increment + write
+    $line += 1 ;
+    open( OCTET, ">", $CONFIG{'ipfile'} );
+    print OCTET $line . "\n";
+    close( OCTET );
+
+    return( $ip );
+}
+
+
+
 =begin doc
 
   If the user specified a role for the new instance then execute it.