Coding comments/suggestions - first python script - sshd/ftpd blocking

[avinashc@yahoo.com]

If anyone is interested in a /etc/hosts.deny automatic update script
(Unix only) based on sshd/vsftpd attacks, here's a python script:

http://www.aczoom.com/tools/blockhosts/

This is a beta release, and my first attempt at Python coding.
Any comments, suggestions, pointers on using more common Python idioms
or example coding snippets, etc, welcome!

Thanks!

[bruno modulix]

Re: Coding comments/suggestions - first python script - sshd/ftpdblocking

avinashc@yahoo. com wrote:[color=blue]
> If anyone is interested in a /etc/hosts.deny automatic update script
> (Unix only) based on sshd/vsftpd attacks, here's a python script:
> http://www.aczoom.com/tools/blockhosts/
>
> This is a beta release, and my first attempt at Python coding.
> Any comments, suggestions, pointers on using more common Python idioms
> or example coding snippets, etc, welcome![/color]

First thing: I had *many* indentation errors (emacs + python_mode on a
linux-box). *Please* take care of this.

I just gave a quick glance, not even pretending to really understand
what the code do, so what follow are just some general advices:

***
def die(msg, ex=None):
print msg
if ex: print ex
sys.exit(1)

- errors messages (including usage) should be written to stderr (stdout
is for normal output)
- you may want to use positional arguments (*args) instead of 'ex'

def die(msg, *args):
print >> sys.stderr, msg
for ex in args:
print >> sys.stderr, ex
sys.exit(1)

***
class LockFile:
(...)
def lock(self):
try:
try:
self.fp = open(self.path, "r+")
# r+ prevents trashing the file!
except Exception, e :

You should use IOError instead of Exception here.
*Always* use the most specific exception class possible.

if e.errno == errno.ENOENT: # no such file

Here if you have anything else than an IOError (well, anything that
doesn't have a 'errno' attribute), you'll get an AttributeError. ..
(...)

if DEBUG: print " ... first r+ lock file open failed, so opened
with w+ mode"

You may want to define a 'debug_trace' function (or use an existing
trace/log lib) that encapsulate the test...

***
class BlockHosts:
(...)
def load_hosts_deny (self, logoffsets):
self.__remainin g_lines = []

if self.__verbose: print " ... hosts.deny: loading from ", self.__denyfile

Same as for DEBUG : you may want to encapsulate the test in a method.

HTH
Bruno
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb@xiludom. gro'.split('@')])"