/usr/lib/python2.7/dist-packages/metadataserver/address.py is in python-django-maas 1.5.4+bzr2294-0ubuntu1.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | # Copyright 2012 Canonical Ltd. This software is licensed under the
# GNU Affero General Public License version 3 (see the file LICENSE).
"""Figure out server address for the maas_url setting."""
from __future__ import (
absolute_import,
print_function,
unicode_literals,
)
str = None
__metaclass__ = type
__all__ = [
'guess_server_address',
]
from fcntl import ioctl
from os import environ
import re
import socket
import struct
from subprocess import check_output
from metadataserver import logger
# fcntl operation as defined in <ioctls.h>. This is GNU/Linux-specific!
SIOCGIFADDR = 0x8915
def get_command_output(*command_line):
"""Execute a command line, and return its output.
Raises an exception if return value is nonzero.
:param *command_line: Words for the command line. No shell expansions
are performed.
:type *command_line: Sequence of unicode.
:return: Output from the command.
:rtype: List of unicode, one per line.
"""
env = {
variable: value
for variable, value in environ.items()
if not variable.startswith('LC_')
}
env.update({
'LC_ALL': 'C',
'LANG': 'en_US.UTF-8',
})
return check_output(command_line, env=env).splitlines()
def find_default_interface(ip_route_output):
"""Find the network interface used for the system's default route.
If no default is found, makes a guess.
:param ip_route_output: Output lines from "ip route show" output.
:type ip_route_output: Sequence of unicode.
:return: unicode, or None.
"""
route_lines = list(ip_route_output)
for line in route_lines:
match = re.match('default\s+.*\sdev\s+([^\s]+)', line)
if match is not None:
return match.groups()[0]
# Still nothing? Try the first recognizable interface in the list.
for line in route_lines:
match = re.match('\s*(?:\S+\s+)*dev\s+([^\s]+)', line)
if match is not None:
return match.groups()[0]
return None
def get_ip_address(interface):
"""Get the IP address for a given network interface."""
# Apparently the netifaces module would do this for us.
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
interface_name = struct.pack(b'256s', interface[:15])
try:
info = ioctl(s.fileno(), SIOCGIFADDR, interface_name)
except IOError as e:
logger.warn(
"Could not determine address for apparent default interface %s "
"(%s)"
% (interface, e))
return None
return socket.inet_ntoa(info[20:24])
def guess_server_address():
"""Make a guess as to this server's IP address."""
ip_route_output = get_command_output(
'/bin/ip', '-oneline', 'route', 'show')
interface = find_default_interface(ip_route_output)
if interface is None:
return socket.gethostname()
else:
return get_ip_address(interface)
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