/usr/lib/python3/dist-packages/provisioningserver/utils/dhclient.py is in python3-maas-provisioningserver 2.4.0~beta2-6865-gec43e47e6-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# GNU Affero General Public License version 3 (see the file LICENSE).
"""Helpers for inspecting dhclient."""
__all__ = [
'get_dhclient_info',
]
import os
import re
from provisioningserver.utils.fs import read_text_file
from provisioningserver.utils.ps import get_running_pids_with_command
re_entry = re.compile(
r'''
^\s* # Ignore leading whitespace on each line.
lease # Look only lease stanzas.
\s+{ # Open bracket.
([^}]+) # Capture the contents of lease.
} # Close bracket.
''',
re.MULTILINE | re.DOTALL | re.VERBOSE)
def get_lastest_fixed_address(lease_path):
"""Return the lastest fixed address assigned in `lease_path`."""
try:
lease_contents = read_text_file(lease_path)
except FileNotFoundError:
return None
matches = re_entry.findall(lease_contents)
if len(matches) > 0:
# Get the IP address assigned to the interface.
last_lease = matches[-1]
for line in last_lease.splitlines():
line = line.strip()
if len(line) > 0:
statement, value = line.split(" ", 1)
if statement in ["fixed-address", "fixed-address6"]:
return value.split(";", 1)[0].strip()
# No matches or unable to identify fixed-address{6} in the last match.
return None
def get_dhclient_info(proc_path="/proc"):
"""Return dictionary mapping interfaces to assigned address from
dhclient.
"""
dhclient_pids = get_running_pids_with_command(
"dhclient", proc_path=proc_path)
dhclient_info = {}
for pid in dhclient_pids:
cmdline = read_text_file(
os.path.join(proc_path, str(pid), "cmdline")).split("\x00")
if "-lf" in cmdline:
idx_lf = cmdline.index("-lf")
lease_path = cmdline[idx_lf + 1] # After '-lf' option.
interface_name = cmdline[-2] # Last argument.
ip_address = get_lastest_fixed_address(lease_path)
if (ip_address is not None and
len(ip_address) > 0 and not ip_address.isspace()):
dhclient_info[interface_name] = ip_address
return dhclient_info
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