From b0b002d7fbebfb08908b2d095c420833ef1c6784 Mon Sep 17 00:00:00 2001
From: Nicolas Simonds <nic@metacloud.com>
Date: Thu, 6 Sep 2012 14:05:43 -0700
Subject: [PATCH] Make the ability to determine the SysV runlevel on Upstart
 track how the system does it

This cures a problem where Salt cannot tell if any of the SysV-style services
are enabled, because it cannot reliably determine the current runlevel.
(strictly speaking, the current method of "guess 2 if the command fails" also
works, but is sub-wonderful)
---
 salt/modules/upstart.py | 60 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 5 deletions(-)

diff --git a/salt/modules/upstart.py b/salt/modules/upstart.py
index e9f05ce37e..ccbd7cc0bd 100644
--- a/salt/modules/upstart.py
+++ b/salt/modules/upstart.py
@@ -49,18 +49,68 @@ def __virtual__():
     return False
 
 
+def _find_utmp():
+    '''
+    Figure out which utmp file to use when determining runlevel.
+    Sometimes /var/run/utmp doesn't exist, /run/utmp is the new hotness.
+    '''
+    result = {}
+    # These are the likely locations for the file on Ubuntu
+    for utmp in ('/var/run/utmp', '/run/utmp'):
+        try:
+            result[os.stat(utmp).st_mtime] = utmp
+        except:
+            pass
+    return result[sorted(result.keys()).pop()]
+
+
+def _default_runlevel():
+    '''
+    Try to figure out the default runlevel.  It is kept in
+    /etc/init/rc-sysinit.conf, but can be overridden with entries
+    in /etc/inittab, or via the kernel command-line at boot
+    '''
+    # Try to get the "main" default.  If this fails, throw up our
+    # hands and just guess "2", because things are horribly broken
+    try:
+        for line in open('/etc/init/rc-sysinit.conf'):
+            if line.startswith('env DEFAULT_RUNLEVEL'):
+                runlevel = line.split('=')[-1].strip()
+    except:
+        return '2'
+
+    # Look for an optional "legacy" override in /etc/inittab
+    try:
+        for line in open('/etc/inittab'):
+            if not line.startswith('#') and 'initdefault' in line:
+                runlevel = line.split(':')[1]
+    except:
+        pass
+
+    # The default runlevel can also be set via the kernel command-line.
+    # Kinky.
+    try:
+        valid_strings = set(('0', '1', '2', '3', '4', '5', '6', 's', 'S', '-s', 'single'))
+        for line in open('/proc/cmdline'):
+            for arg in split(line.strip()):
+                if arg in valid_strings:
+                    runlevel = arg
+                    break
+    except:
+        pass
+
+    return runlevel
+
 def _runlevel():
     '''
     Return the current runlevel
-    TODO: Should this return the "default" runlevel? For example, bad
-    things will likely happen when 'salt' is run in single-user mode.
     '''
-    out = __salt__['cmd.run']('runlevel').strip()
+    out = __salt__['cmd.run']('runlevel {0}'.format(_find_utmp())).strip()
     try:
         return out.split()[1]
     except IndexError:
-        # The runlevel is unknown, return 3 for a default
-        return '2'
+        # The runlevel is unknown, return the default
+        return _default_runlevel()
 
 
 def _is_symlink(name):