Show the virtual machine name in dstat instead of showing qemu

Do you run dstat to watch Linux KVM hypervisors, but wish process names showed virtual machine names?  Me too.

This patch does just that:

--- a/usr/bin/dstat	2009-11-24 01:30:11.000000000 -0800
+++ b/usr/bin/dstat	2014-11-07 10:20:09.719148833 -0800
@@ -1946,6 +1946,12 @@
         return os.path.basename(name)
     return name

+def index_containing_substring(the_list, substring):
+	for i, s in enumerate(the_list):
+		if substring in s:
+			return i
+	return -1
+
 def getnamebypid(pid, name):
     ret = None
     try:
@@ -1956,6 +1962,10 @@
         if ret.startswith('-'):
             ret = basename(cmdline[-2])
             if ret.startswith('-'): raise
+        if any("qemu" in s for s in cmdline):
+            idx = index_containing_substring(cmdline, '-name')
+            if idx >= 0:
+                ret = cmdline[idx+1]
         if not ret: raise
     except:
         ret = basename(name)