sshuttle/sshuttle/hostwatch.py
vieira 4241381d82 Backward compatibility with Python 2.4 (server)
It is often the case that the user has no administrative control over
the server that is being used. As such it is important to support as
many versions as possible, at least on the remote server end. These
fixes will allow sshuttle to be used with servers that have only
python 2.4 or python 2.6 installed while hopefully not breaking the
compatibility with 2.7 and 3.5.
2016-04-03 13:14:02 +10:00

298 lines
7.5 KiB
Python

import time
import socket
import re
import select
import errno
import os
import sys
import platform
import subprocess as ssubprocess
import sshuttle.helpers as helpers
from sshuttle.helpers import log, debug1, debug2, debug3
POLL_TIME = 60 * 15
NETSTAT_POLL_TIME = 30
CACHEFILE = os.path.expanduser('~/.sshuttle.hosts')
_nmb_ok = True
_smb_ok = True
hostnames = {}
queue = {}
try:
null = open('/dev/null', 'wb')
except IOError:
_, e = sys.exc_info()[:2]
log('warning: %s\n' % e)
null = os.popen("sh -c 'while read x; do :; done'", 'wb', 4096)
def _is_ip(s):
return re.match(r'\d+\.\d+\.\d+\.\d+$', s)
def write_host_cache():
tmpname = '%s.%d.tmp' % (CACHEFILE, os.getpid())
try:
f = open(tmpname, 'wb')
for name, ip in sorted(hostnames.items()):
f.write(('%s,%s\n' % (name, ip)).encode("ASCII"))
f.close()
os.chmod(tmpname, 384) # 600 in octal, 'rw-------'
os.rename(tmpname, CACHEFILE)
finally:
try:
os.unlink(tmpname)
except:
pass
def read_host_cache():
try:
f = open(CACHEFILE)
except IOError:
_, e = sys.exc_info()[:2]
if e.errno == errno.ENOENT:
return
else:
raise
for line in f:
words = line.strip().split(',')
if len(words) == 2:
(name, ip) = words
name = re.sub(r'[^-\w]', '-', name).strip()
ip = re.sub(r'[^0-9.]', '', ip).strip()
if name and ip:
found_host(name, ip)
def found_host(hostname, ip):
hostname = re.sub(r'\..*', '', hostname)
hostname = re.sub(r'[^-\w]', '_', hostname)
if (ip.startswith('127.') or ip.startswith('255.')
or hostname == 'localhost'):
return
oldip = hostnames.get(hostname)
if oldip != ip:
hostnames[hostname] = ip
debug1('Found: %s: %s\n' % (hostname, ip))
sys.stdout.write('%s,%s\n' % (hostname, ip))
write_host_cache()
def _check_etc_hosts():
debug2(' > hosts\n')
for line in open('/etc/hosts'):
line = re.sub(r'#.*', '', line)
words = line.strip().split()
if not words:
continue
ip = words[0]
names = words[1:]
if _is_ip(ip):
debug3('< %s %r\n' % (ip, names))
for n in names:
check_host(n)
found_host(n, ip)
def _check_revdns(ip):
debug2(' > rev: %s\n' % ip)
try:
r = socket.gethostbyaddr(ip)
debug3('< %s\n' % r[0])
check_host(r[0])
found_host(r[0], ip)
except socket.herror:
pass
def _check_dns(hostname):
debug2(' > dns: %s\n' % hostname)
try:
ip = socket.gethostbyname(hostname)
debug3('< %s\n' % ip)
check_host(ip)
found_host(hostname, ip)
except socket.gaierror:
pass
def _check_netstat():
debug2(' > netstat\n')
argv = ['netstat', '-n']
try:
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null)
content = p.stdout.read().decode("ASCII")
p.wait()
except OSError:
_, e = sys.exc_info()[:2]
log('%r failed: %r\n' % (argv, e))
return
for ip in re.findall(r'\d+\.\d+\.\d+\.\d+', content):
debug3('< %s\n' % ip)
check_host(ip)
def _check_smb(hostname):
return
global _smb_ok
if not _smb_ok:
return
argv = ['smbclient', '-U', '%', '-L', hostname]
debug2(' > smb: %s\n' % hostname)
try:
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null)
lines = p.stdout.readlines()
p.wait()
except OSError:
_, e = sys.exc_info()[:2]
log('%r failed: %r\n' % (argv, e))
_smb_ok = False
return
lines.reverse()
# junk at top
while lines:
line = lines.pop().strip()
if re.match(r'Server\s+', line):
break
# server list section:
# Server Comment
# ------ -------
while lines:
line = lines.pop().strip()
if not line or re.match(r'-+\s+-+', line):
continue
if re.match(r'Workgroup\s+Master', line):
break
words = line.split()
hostname = words[0].lower()
debug3('< %s\n' % hostname)
check_host(hostname)
# workgroup list section:
# Workgroup Master
# --------- ------
while lines:
line = lines.pop().strip()
if re.match(r'-+\s+', line):
continue
if not line:
break
words = line.split()
(workgroup, hostname) = (words[0].lower(), words[1].lower())
debug3('< group(%s) -> %s\n' % (workgroup, hostname))
check_host(hostname)
check_workgroup(workgroup)
if lines:
assert(0)
def _check_nmb(hostname, is_workgroup, is_master):
return
global _nmb_ok
if not _nmb_ok:
return
argv = ['nmblookup'] + ['-M'] * is_master + ['--', hostname]
debug2(' > n%d%d: %s\n' % (is_workgroup, is_master, hostname))
try:
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null)
lines = p.stdout.readlines()
rv = p.wait()
except OSError:
_, e = sys.exc_info()[:2]
log('%r failed: %r\n' % (argv, e))
_nmb_ok = False
return
if rv:
log('%r returned %d\n' % (argv, rv))
return
for line in lines:
m = re.match(r'(\d+\.\d+\.\d+\.\d+) (\w+)<\w\w>\n', line)
if m:
g = m.groups()
(ip, name) = (g[0], g[1].lower())
debug3('< %s -> %s\n' % (name, ip))
if is_workgroup:
_enqueue(_check_smb, ip)
else:
found_host(name, ip)
check_host(name)
def check_host(hostname):
if _is_ip(hostname):
_enqueue(_check_revdns, hostname)
else:
_enqueue(_check_dns, hostname)
_enqueue(_check_smb, hostname)
_enqueue(_check_nmb, hostname, False, False)
def check_workgroup(hostname):
_enqueue(_check_nmb, hostname, True, False)
_enqueue(_check_nmb, hostname, True, True)
def _enqueue(op, *args):
t = (op, args)
if queue.get(t) is None:
queue[t] = 0
def _stdin_still_ok(timeout):
r, w, x = select.select([sys.stdin.fileno()], [], [], timeout)
if r:
b = os.read(sys.stdin.fileno(), 4096)
if not b:
return False
return True
def hw_main(seed_hosts):
if helpers.verbose >= 2:
helpers.logprefix = 'HH: '
else:
helpers.logprefix = 'hostwatch: '
debug1('Starting hostwatch with Python version %s\n'
% platform.python_version())
read_host_cache()
_enqueue(_check_etc_hosts)
_enqueue(_check_netstat)
check_host('localhost')
check_host(socket.gethostname())
check_workgroup('workgroup')
check_workgroup('-')
for h in seed_hosts:
check_host(h)
while 1:
now = time.time()
for t, last_polled in list(queue.items()):
(op, args) = t
if not _stdin_still_ok(0):
break
maxtime = POLL_TIME
if op == _check_netstat:
maxtime = NETSTAT_POLL_TIME
if now - last_polled > maxtime:
queue[t] = time.time()
op(*args)
try:
sys.stdout.flush()
except IOError:
break
# FIXME: use a smarter timeout based on oldest last_polled
if not _stdin_still_ok(1):
break