From d3a0958c09c73a78fda6e922b749a1b98036e984 Mon Sep 17 00:00:00 2001
From: Scott Moser <smoser@brickies.net>
Date: Sun, 19 Nov 2017 16:27:06 -0700
Subject: EC2: Kill dhclient process used in sandbox dhclient.

dhclient runs, obtains a address and then backgrounds itself.
cloud-init did not take care to kill it after it was done with it.
After it has run and created the leases, we can kill it.

LP: #1732964
---
 cloudinit/net/dhcp.py            | 9 ++++++++-
 cloudinit/net/tests/test_dhcp.py | 9 ++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

(limited to 'cloudinit')

diff --git a/cloudinit/net/dhcp.py b/cloudinit/net/dhcp.py
index 0cba7032..f3a412a9 100644
--- a/cloudinit/net/dhcp.py
+++ b/cloudinit/net/dhcp.py
@@ -8,6 +8,7 @@ import configobj
 import logging
 import os
 import re
+import signal
 
 from cloudinit.net import find_fallback_nic, get_devicelist
 from cloudinit import temp_utils
@@ -119,7 +120,13 @@ def dhcp_discovery(dhclient_cmd_path, interface, cleandir):
     cmd = [sandbox_dhclient_cmd, '-1', '-v', '-lf', lease_file,
            '-pf', pid_file, interface, '-sf', '/bin/true']
     util.subp(cmd, capture=True)
-    return parse_dhcp_lease_file(lease_file)
+    pid = None
+    try:
+        pid = int(util.load_file(pid_file).strip())
+        return parse_dhcp_lease_file(lease_file)
+    finally:
+        if pid:
+            os.kill(pid, signal.SIGKILL)
 
 
 def networkd_parse_lease(content):
diff --git a/cloudinit/net/tests/test_dhcp.py b/cloudinit/net/tests/test_dhcp.py
index 1c1f504a..3d8e15c0 100644
--- a/cloudinit/net/tests/test_dhcp.py
+++ b/cloudinit/net/tests/test_dhcp.py
@@ -2,6 +2,7 @@
 
 import mock
 import os
+import signal
 from textwrap import dedent
 
 from cloudinit.net.dhcp import (
@@ -114,8 +115,9 @@ class TestDHCPDiscoveryClean(CiTestCase):
         self.assertEqual('eth9', call[0][1])
         self.assertIn('/var/tmp/cloud-init/cloud-init-dhcp-', call[0][2])
 
+    @mock.patch('cloudinit.net.dhcp.os.kill')
     @mock.patch('cloudinit.net.dhcp.util.subp')
-    def test_dhcp_discovery_run_in_sandbox(self, m_subp):
+    def test_dhcp_discovery_run_in_sandbox(self, m_subp, m_kill):
         """dhcp_discovery brings up the interface and runs dhclient.
 
         It also returns the parsed dhcp.leases file generated in the sandbox.
@@ -134,6 +136,10 @@ class TestDHCPDiscoveryClean(CiTestCase):
         """)
         lease_file = os.path.join(tmpdir, 'dhcp.leases')
         write_file(lease_file, lease_content)
+        pid_file = os.path.join(tmpdir, 'dhclient.pid')
+        my_pid = 1
+        write_file(pid_file, "%d\n" % my_pid)
+
         self.assertItemsEqual(
             [{'interface': 'eth9', 'fixed-address': '192.168.2.74',
               'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1'}],
@@ -149,6 +155,7 @@ class TestDHCPDiscoveryClean(CiTestCase):
                 [os.path.join(tmpdir, 'dhclient'), '-1', '-v', '-lf',
                  lease_file, '-pf', os.path.join(tmpdir, 'dhclient.pid'),
                  'eth9', '-sf', '/bin/true'], capture=True)])
+        m_kill.assert_has_calls([mock.call(my_pid, signal.SIGKILL)])
 
 
 class TestSystemdParseLeases(CiTestCase):
-- 
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