bcfg2-server silently allows multiple instances

[naapuri]

bcfg2-server seems to allow multiple instances to be listening on the same port. (I didn't know this was even possible!) This might cause confusion.

How to reproduce (at least on my debian etch with svn build 2531):

1. Start bcfg2-server: # /etc/init.d/bcfg2-server start

2. Start bcfg2-server manually: # bcfg2-server &

3. See netstat output:

# netstat -plunt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 x.x.x.x:6789          0.0.0.0:*               LISTEN     3909/python
tcp        0      0 x.x.x.x:6789          0.0.0.0:*               LISTEN     3906/python
(...)

How to fix: bcfg2-server should detect the situation where someone is already listening on the port and refuse to start.

[desai]

I have fixed this in [820b2a677475e26aa29a23cd9c4eadcaf4ec4730] (SVN r2533). Upon running a second instance of the server, i now get:

[0:20] sudo ./src/sbin/bcfg2-server                                                                                                                                 
Failed to bind to socket