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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, get_env
POLL_TIME = 60 * 15
NETSTAT_POLL_TIME = 30
CACHEFILE = os.path.expanduser('~/.sshuttle.hosts')
hostnames = {}
queue = {}
try:
null = open(os.devnull, 'wb')
except IOError:
_, e = sys.exc_info()[:2]
log('warning: %s' % 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 BaseException:
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(name, ip):
hostname = re.sub(r'\..*', '', name)
hostname = re.sub(r'[^-\w\.]', '_', hostname)
if (ip.startswith('127.') or ip.startswith('255.') or
hostname == 'localhost'):
return
if hostname != name:
found_host(hostname, ip)
oldip = hostnames.get(name)
if oldip != ip:
hostnames[name] = ip
debug1('Found: %s: %s' % (name, ip))
sys.stdout.write('%s,%s\n' % (name, ip))
write_host_cache()
def _check_etc_hosts():
debug2(' > hosts')
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' % (ip, names))
for n in names:
check_host(n)
found_host(n, ip)
def _check_revdns(ip):
debug2(' > rev: %s' % ip)
try:
r = socket.gethostbyaddr(ip)
debug3('< %s' % r[0])
check_host(r[0])
found_host(r[0], ip)
except (socket.herror, UnicodeError):
pass
def _check_dns(hostname):
debug2(' > dns: %s' % hostname)
try:
ip = socket.gethostbyname(hostname)
debug3('< %s' % ip)
check_host(ip)
found_host(hostname, ip)
except (socket.gaierror, UnicodeError):
pass
def _check_netstat():
debug2(' > netstat')
argv = ['netstat', '-n']
try:
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null,
env=get_env())
content = p.stdout.read().decode("ASCII")
p.wait()
except OSError:
_, e = sys.exc_info()[:2]
log('%r failed: %r' % (argv, e))
return
for ip in re.findall(r'\d+\.\d+\.\d+\.\d+', content):
debug3('< %s' % ip)
check_host(ip)
def check_host(hostname):
if _is_ip(hostname):
_enqueue(_check_revdns, hostname)
else:
_enqueue(_check_dns, hostname)
def _enqueue(op, *args):
t = (op, args)
if queue.get(t) is None:
queue[t] = 0
def _stdin_still_ok(timeout):
r, _, _ = 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, auto_hosts):
helpers.logprefix = 'HH: '
debug1('Starting hostwatch with Python version %s'
% platform.python_version())
for h in seed_hosts:
check_host(h)
if auto_hosts:
read_host_cache()
_enqueue(_check_etc_hosts)
_enqueue(_check_netstat)
check_host('localhost')
check_host(socket.gethostname())
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
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