Support gnome terminals too

Caution: code is incomplete - can't set a default type from the CLI
and in some places the phrase xterm should be replaced by terminal.

mininet/term.py

@@ -0,0 +1,55 @@
+"""
+Terminal creation and cleanup.
+Utility functions to run a term (connected via screen(1)) on each host.
+
+Requires GNU screen(1) and xterm(1).
+Optionally uses gnome-terminal.
+"""
+
+import re
+from subprocess import Popen
+
+from mininet.log import error
+from mininet.util import quietRun
+
+def makeTerm( node, title = '', term = 'xterm' ):
+    """Run screen on a node, and hook up an xterm.
+       node: Node object
+       title: base title
+       returns: process created"""
+    title += ': ' + node.name
+    if not node.inNamespace:
+        title += ' (root)'
+    cmd = ''
+    if term == 'xterm':
+        cmd = [ 'xterm', '-title', title, '-e' ]
+    elif term == 'gnome':
+        cmd = [ 'gnome-terminal', '--title', title, '-e' ]
+    else:
+        error( 'invalid terminal type: %s' % term )
+        return
+    if not node.execed:
+        node.cmd( 'screen -dmS ' + node.name)
+        #cmd += [ 'screen', '-D', '-RR', '-S', node.name ]
+        # Compress these for gnome-terminal, which expects one token to follow
+        # the -e option    .
+        cmd += [ 'screen -D -RR -S ' + node.name ]
+    else:
+        cmd += [ 'sh', '-c', 'exec tail -f /tmp/' + node.name + '*.log' ]
+    return Popen( cmd )
+
+def cleanUpScreens():
+    "Remove moldy old screen sessions."
+    r = r'(\d+.[hsc]\d+)'
+    output = quietRun( 'screen -ls' ).split( '\n' )
+    for line in output:
+        m = re.search( r, line )
+        if m:
+            quietRun( 'screen -S ' + m.group( 1 ) + ' -X quit' )
+
+def makeTerms( nodes, title = '', term = 'xterm' ):
+    """Create terminals.
+       nodes: list of Node objects
+       title: base title for each
+       returns: list of created terminal processes"""
+    return [ makeTerm( node, title, term ) for node in nodes ]