From b415b30624f0dcbe9fd574c28593e8fd38a8d9c8 Mon Sep 17 00:00:00 2001
From: Mohammed Gamal <mgamal@redhat.com>
Date: Thu, 2 Jun 2022 14:39:42 +0200
Subject: [PATCH 1/2] Fix if hangs (#2283)

RH-Author: Mohamed Gamal Morsy <mmorsy@redhat.com>
RH-MergeRequest: 2: Fix if hangs (#2283)
RH-Commit: [1/2] cf3b0a2d65eb9eeeceab6d74e376e729e06a01ed
RH-Bugzilla: 2092753
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
RH-Acked-by: Cathy Avery <cavery@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2092753

Signed-off-by: Laveesh Rohra <larohra@microsoft.com>
(cherry picked from commit 05cd6437ba90928788ef18c8b9fc8a6dbaf47c7d)

Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
---
 azurelinuxagent/common/osutil/default.py | 26 ++++++++----------------
 azurelinuxagent/common/osutil/ubuntu.py  | 22 +++++++++-----------
 tests/common/osutil/test_default.py      | 11 +++-------
 3 files changed, 21 insertions(+), 38 deletions(-)

diff --git a/azurelinuxagent/common/osutil/default.py b/azurelinuxagent/common/osutil/default.py
index 066e1431..820016c1 100644
--- a/azurelinuxagent/common/osutil/default.py
+++ b/azurelinuxagent/common/osutil/default.py
@@ -1163,25 +1163,15 @@ class DefaultOSUtil(object):
     def restart_if(self, ifname, retries=3, wait=5):
         retry_limit = retries + 1
         for attempt in range(1, retry_limit):
-            try:
-                shellutil.run_command(["ifdown", ifname])
-                shellutil.run_command(["ifup", ifname])
+            return_code = shellutil.run("ifdown {0} && ifup {0}".format(ifname), expected_errors=[1] if attempt < retries else [])
+            if return_code == 0:
                 return
-            except shellutil.CommandError as cmd_err:
-                
-                msg = "failed to restart {0}: returncode={1}\n[stdout]{2}\n\n[stderr]{3}\n"\
-                    .format(ifname, cmd_err.returncode, cmd_err.stdout, cmd_err.stderr)
-                
-                if cmd_err.returncode == 1:
-                    logger.info(msg)
-                else:
-                    logger.warn(msg)
-
-                if attempt < retry_limit:
-                    logger.info("retrying in {0} seconds".format(wait))
-                    time.sleep(wait)
-                else:
-                    logger.warn("exceeded restart retries")
+            logger.warn("failed to restart {0}: return code {1}".format(ifname, return_code))
+            if attempt < retry_limit:
+                logger.info("retrying in {0} seconds".format(wait))
+                time.sleep(wait)
+            else:
+                logger.warn("exceeded restart retries")
 
     def publish_hostname(self, hostname):
         self.set_dhcp_hostname(hostname)
diff --git a/azurelinuxagent/common/osutil/ubuntu.py b/azurelinuxagent/common/osutil/ubuntu.py
index 249e1120..5a21511c 100644
--- a/azurelinuxagent/common/osutil/ubuntu.py
+++ b/azurelinuxagent/common/osutil/ubuntu.py
@@ -142,19 +142,17 @@ class UbuntuOSUtil(Ubuntu16OSUtil):
         Restart an interface by bouncing the link. systemd-networkd observes
         this event, and forces a renew of DHCP.
         """
-        retry_limit=retries+1
+        retry_limit = retries+1
         for attempt in range(1, retry_limit):
-            try:
-                shellutil.run_command(["ip", "link", "set", ifname, "down"])
-                shellutil.run_command(["ip", "link", "set", ifname, "up"])
-
-            except shellutil.CommandError as cmd_err:
-                logger.warn("failed to restart {0}: return code {1}".format(ifname, cmd_err.returncode))
-                if attempt < retry_limit:
-                    logger.info("retrying in {0} seconds".format(wait))
-                    time.sleep(wait)
-                else:
-                    logger.warn("exceeded restart retries")
+            return_code = shellutil.run("ip link set {0} down && ip link set {0} up".format(ifname))
+            if return_code == 0:
+                return
+            logger.warn("failed to restart {0}: return code {1}".format(ifname, return_code))
+            if attempt < retry_limit:
+                logger.info("retrying in {0} seconds".format(wait))
+                time.sleep(wait)
+            else:
+                logger.warn("exceeded restart retries")
 
 
 class UbuntuSnappyOSUtil(Ubuntu14OSUtil):
diff --git a/tests/common/osutil/test_default.py b/tests/common/osutil/test_default.py
index 65d7ae0f..d6eae68f 100644
--- a/tests/common/osutil/test_default.py
+++ b/tests/common/osutil/test_default.py
@@ -49,20 +49,15 @@ class TestOSUtil(AgentTestCase):
         # setup
         retries = 3
         ifname = 'dummy'
-        with patch.object(shellutil, "run_command") as run_patch:
-            run_patch.side_effect = shellutil.CommandError("ifupdown dummy", 1, "", "")
+        with patch.object(shellutil, "run") as run_patch:
+            run_patch.return_value = 1
 
             # execute
             osutil.DefaultOSUtil.restart_if(osutil.DefaultOSUtil(), ifname=ifname, retries=retries, wait=0)
 
             # assert
             self.assertEqual(run_patch.call_count, retries)
-            cmd_queue = list(args[0] for (args, _) in run_patch.call_args_list)            
-            while cmd_queue:
-                self.assertEqual(cmd_queue.pop(0), ["ifdown", ifname])
-                # We don't expect the following command to be called because 'dummy' does
-                # not exist.
-                self.assertNotEqual(cmd_queue[0] if cmd_queue else None, ["ifup", ifname])
+            self.assertEqual(run_patch.call_args_list[0][0][0], 'ifdown {0} && ifup {0}'.format(ifname))
                 
     def test_get_dvd_device_success(self):
         with patch.object(os, 'listdir', return_value=['cpu', 'cdrom0']):
-- 
2.31.1