Tag node bash processes and add attach script

Try invoking bash processes with -s mininet:host,
for easy identification of hosts. This enables
easy attachment using the util/m script.
closes #121

mininet/clean.py

@@ -27,12 +27,15 @@ def cleanup():
     info("*** Removing excess controllers/ofprotocols/ofdatapaths/pings/noxes"
          "\n")
     zombies = 'controller ofprotocol ofdatapath ping nox_core lt-nox_core '
-    zombies += 'ovs-openflowd udpbwtest'
+    zombies += 'ovs-openflowd udpbwtest mnexec'
     # Note: real zombie processes can't actually be killed, since they
     # are already (un)dead. Then again,
     # you can't connect to them either, so they're mostly harmless.
     sh( 'killall -9 ' + zombies + ' 2> /dev/null' )
 
+    # And kill off sudo mnexec
+    sh( 'pkill -9 -f "sudo mnexec"')
+
     info( "*** Removing junk from /tmp\n" )
     sh( 'rm -f /tmp/vconn* /tmp/vlogs* /tmp/*.out /tmp/*.log' )
 

mininet/node.py

@@ -118,7 +118,8 @@ class Node( object ):
         if self.inNamespace:
             opts += 'n'
         # bash -m: enable job control
-        cmd = [ 'mnexec', opts, 'bash', '-m' ]
+        # -s: pass $* to shell, and make process easy to find in ps
+        cmd = [ 'mnexec', opts, 'bash', '-ms', 'mininet:' + self.name ]
         self.shell = Popen( cmd, stdin=PIPE, stdout=PIPE, stderr=STDOUT,
                             close_fds=True )
         self.stdin = self.shell.stdin

util/m

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# Attach to a Mininet host and run a command
+
+if [ -z $1 ]; then
+  echo "usage: $0 host cmd [args...]"
+  exit 1
+else
+  host=$1
+fi
+
+pid=`pgrep -f mininet:$host`
+if [ "$pid" == "" ]; then
+  echo "Could not find Mininet host $host"
+  exit 2
+fi
+
+if [ -z $2 ]; then
+  cmd='bash'
+else
+  shift
+  cmd=$*
+fi
+
+cgroup=/sys/fs/cgroup/cpu/$host
+if [ -d "$cgroup" ]; then
+  cg="-g $host"
+fi
+
+exec sudo mnexec -a $pid $cg $cmd