/etc/hosts ip update

Question

Hi all
What I would like to do is have DHCP (through NetworkManager) update the /etc/hosts file when it gets an IP. The problem I am running into now is that I have to go and manually edit my hosts file to update my current IP, otherwise a program the networking code in my java program breaks
In other words, I need 192.168.1.106 to be kept current.
/etc/hosts
#<ip-address> <hostname.domain.org> <hostname>
127.0.0.1 localhost.localdomain localhost
192.168.1.106 arch61 localhost
# End of file
/etc/resolv.conf
# generated by NetworkManager, do not edit!
search hsd1.ca.comcast.net.
nameserver 68.87.76.178
nameserver 68.87.78.130
/etc/rc.conf
HOSTNAME="arch61"
lo="lo 127.0.0.1"
eth0="dhcp"
INTERFACES=(lo !eth0)
#gateway="default gw 192.168.0.1"
ROUTES=(!gateway)
Thanks

Answer 1

updated,,, better error handling, etc
ipup.py
#!/usr/bin/env python
#################################notes#################################
# ipup.py r3 #
# ipup.py updates the hosts file,with the current *AN ip address #
# ~configure~ #
# hosts = '/etc/hosts' = location of hosts file #
# interface = 'ath0|wlan0|etc0' = name of the inerface to poll #
import re
from subprocess import PIPE, Popen
hosts = '/etc/hosts'
interface = 'ath0'
handle = open(hosts, 'r')
hbuf = handle.read()
handle.close()
ibuf = Popen(['ifconfig', interface], stdout=PIPE).stdout.read()
ipat = re.compile('inet addr:(\d+\.\d+\.\d+\.\d+) ')
ip = ipat.search(ibuf)
ip = ip and ip.group(1)
hpat = re.compile('(.*\D)(\d+\.\d+\.\d+\.\d+)(.*#ip~up#.*)', re.DOTALL)
ih = hpat.search(hbuf)
if ih and ip:
if ip != ih.group(2):
try:
out = ih.group(1) + ip + ih.group(3)
handle = open(hosts, 'w')
handle.write(out)
print 'updated ip address to', ip
except:
print 'failed to update hosts file,'
print 'maybe you don\'t have permision to write to', hosts
else:
print hosts, 'is already up to date'
else:
ih = ih and ih.group(2)
print 'failed to get ip address(es)'
print 'old ip(' + hosts + '):', ih
print ' new ip(ifconfig):', ip
~~~~~~~~~~~~~~~~~~~~~~~~~~~
don't forget, the hosts file needs to have the line
`````````````````````````````````````````
127.0.0.1 arch61 localhost #ip~up#
``````````````````````````````````````````
Last edited by kumico (2007-12-07 08:57:12)