Delete HA metadata proxy PID and config with elevated privileges

Both files cannot be deleted with the default permissions because
those files are created by the "root" user.

Conflicts:
    neutron/agent/metadata/driver.py
    neutron/tests/functional/agent/l3/framework.py
    neutron/tests/unit/agent/dhcp/test_agent.py

Change-Id: I73dd37b3104fac8d3172f520f71cffd85d040c4b
Closes-Bug: #1907695
(cherry picked from commit 0a0f647ea0)

neutron/agent/linux/external_process.py

@@ -113,7 +113,8 @@ class ProcessManager(MonitoredProcess):
                 utils.execute(cmd, run_as_root=self.run_as_root)
                 # In the case of shutting down, remove the pid file
                 if sig == '9':
-                    fileutils.delete_if_exists(self.get_pid_file_name())
+                    utils.delete_if_exists(self.get_pid_file_name(),
+                                           run_as_root=self.run_as_root)
         elif pid:
             LOG.debug('%(service)s process for %(uuid)s pid %(pid)d is stale, '
                       'ignoring signal %(signal)s',

neutron/agent/linux/utils.py

@@ -38,6 +38,7 @@ from neutron._i18n import _
 from neutron.agent.linux import xenapi_root_helper
 from neutron.common import utils
 from neutron.conf.agent import common as config
+from neutron.privileged.agent.linux import utils as priv_utils
 from neutron import wsgi
 
 
@@ -394,6 +395,14 @@ def is_effective_group(group_id_or_name):
     return group_id_or_name == effective_group_name
 
 
+def delete_if_exists(path, run_as_root=False):
+    """Delete a path, executed as normal user or with elevated privileges"""
+    if run_as_root:
+        priv_utils.delete_if_exists(path)
+    else:
+        fileutils.delete_if_exists(path)
+
+
 class UnixDomainHTTPConnection(httplib.HTTPConnection):
     """Connection class for HTTP over UNIX domain socket."""
     def __init__(self, host, port=None, strict=None, timeout=None,

neutron/agent/metadata/driver.py

@@ -13,7 +13,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import errno
 import grp
 import os
 import pwd
@@ -30,6 +29,7 @@ from neutron._i18n import _
 from neutron.agent.l3 import ha_router
 from neutron.agent.l3 import namespaces
 from neutron.agent.linux import external_process
+from neutron.agent.linux import utils as linux_utils
 
 
 LOG = logging.getLogger(__name__)
@@ -163,13 +163,7 @@ class HaproxyConfigurator(object):
         cfg_path = os.path.join(
             HaproxyConfigurator.get_config_path(state_path),
             "%s.conf" % uuid)
-        try:
-            os.unlink(cfg_path)
-        except OSError as ex:
-            # It can happen that this function is called but metadata proxy
-            # was never spawned so its config file won't exist
-            if ex.errno != errno.ENOENT:
-                raise
+        linux_utils.delete_if_exists(cfg_path, run_as_root=True)
 
 
 class MetadataDriver(object):

neutron/privileged/agent/linux/utils.py

@@ -12,9 +12,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import os
 import re
 
 from oslo_concurrency import processutils
+from oslo_utils import fileutils
 
 from neutron import privileged
 
@@ -40,3 +42,8 @@ def _find_listen_pids_namespace(namespace):
         if m:
             pids.add(m.group('pid'))
     return list(pids)
+
+
+@privileged.default.entrypoint
+def delete_if_exists(path, remove=os.unlink):
+    fileutils.delete_if_exists(path, remove=remove)

neutron/tests/functional/agent/l3/framework.py

@@ -15,6 +15,7 @@
 
 import copy
 import functools
+import os
 
 import mock
 import netaddr
@@ -435,12 +436,15 @@ class L3AgentTestFramework(base.BaseSudoTestCase):
     def _namespace_exists(self, namespace):
         return ip_lib.network_namespace_exists(namespace)
 
-    def _metadata_proxy_exists(self, conf, router):
-        pm = external_process.ProcessManager(
+    def _metadata_proxy(self, conf, router):
+        return external_process.ProcessManager(
             conf,
             router.router_id,
             router.ns_name,
             service=metadata_driver.HAPROXY_SERVICE)
+
+    def _metadata_proxy_exists(self, conf, router):
+        pm = self._metadata_proxy(conf, router)
         return pm.active
 
     def device_exists_with_ips_and_mac(self, expected_device, name_getter,
@@ -501,9 +505,19 @@ class L3AgentTestFramework(base.BaseSudoTestCase):
         # then the devices and iptable rules have also been deleted,
         # so there's no need to check that explicitly.
         self.assertFalse(self._namespace_exists(router.ns_name))
-        common_utils.wait_until_true(
-            lambda: not self._metadata_proxy_exists(self.agent.conf, router),
-            timeout=10)
+        try:
+            common_utils.wait_until_true(
+                lambda: not self._metadata_proxy_exists(self.agent.conf,
+                                                        router),
+                timeout=10)
+        except common_utils.WaitTimeout:
+            pm = self._metadata_proxy(self.agent.conf, router)
+            pid_file = pm.get_pid_file_name()
+            if os.path.exists(pid_file):
+                msg = 'PID file %s still exists and it should not.' % pid_file
+            else:
+                msg = 'PID file %s is not present.' % pid_file
+            self.fail(msg)
 
     def _assert_snat_chains(self, router):
         self.assertFalse(router.iptables_manager.is_chain_empty(

neutron/tests/unit/agent/dhcp/test_agent.py

@@ -34,6 +34,7 @@ from neutron.agent.dhcp import agent as dhcp_agent
 from neutron.agent import dhcp_agent as entry
 from neutron.agent.linux import dhcp
 from neutron.agent.linux import interface
+from neutron.agent.linux import utils as linux_utils
 from neutron.agent.metadata import driver as metadata_driver
 from neutron.common import config as common_config
 from neutron.common import utils
@@ -759,6 +760,12 @@ class TestDhcpAgentEventHandler(base.BaseTestCase):
         self.mock_resize_p = mock.patch('neutron.agent.dhcp.agent.'
                                         'DhcpAgent._resize_process_pool')
         self.mock_resize = self.mock_resize_p.start()
+        self.mock_wait_until_address_ready_p = mock.patch(
+            'neutron.agent.linux.ip_lib.'
+            'IpAddrCommand.wait_until_address_ready')
+        self.mock_wait_until_address_ready_p.start()
+        mock.patch.object(linux_utils, 'delete_if_exists').start()
+        self.addCleanup(self.mock_wait_until_address_ready_p.stop)
 
     def _process_manager_constructor_call(self, ns=FAKE_NETWORK_DHCP_NS):
         return mock.call(conf=cfg.CONF,

neutron/tests/unit/agent/l3/test_agent.py

@@ -55,6 +55,7 @@ from neutron.agent.linux import ip_lib
 from neutron.agent.linux import iptables_manager
 from neutron.agent.linux import pd
 from neutron.agent.linux import ra
+from neutron.agent.linux import utils as linux_utils
 from neutron.agent.metadata import driver as metadata_driver
 from neutron.agent import rpc as agent_rpc
 from neutron.conf.agent import common as agent_config
@@ -3060,9 +3061,10 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
                             dvr_snat_ns.SNAT_NS_PREFIX + 'foo']
         other_namespaces = ['unknown']
 
-        self._cleanup_namespace_test(stale_namespaces,
-                                     [],
-                                     other_namespaces)
+        with mock.patch.object(linux_utils, 'delete_if_exists'):
+            self._cleanup_namespace_test(stale_namespaces,
+                                         [],
+                                         other_namespaces)
 
     def test_cleanup_namespace_with_registered_router_ids(self):
         stale_namespaces = [namespaces.NS_PREFIX + 'cccc',
@@ -3072,9 +3074,10 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
                        {'id': 'aaaa', 'distributed': False}]
         other_namespaces = ['qdhcp-aabbcc', 'unknown']
 
-        self._cleanup_namespace_test(stale_namespaces,
-                                     router_list,
-                                     other_namespaces)
+        with mock.patch.object(linux_utils, 'delete_if_exists'):
+            self._cleanup_namespace_test(stale_namespaces,
+                                         router_list,
+                                         other_namespaces)
 
     def test_create_dvr_gateway(self):
         agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)