From 531f2da33d584e362b600e7925e658f718c4d04f Mon Sep 17 00:00:00 2001
From: Thierry Parmentelat <thierry.parmentelat@inria.fr>
Date: Fri, 21 Oct 2022 14:00:10 +0200
Subject: [PATCH] try to work around the broken gethostbyaddr more thoroughly

---
 system/PlcapiUrlScanner.py | 20 +++++++++++---------
 system/TestPlc.py          | 38 +++++++-------------------------------
 system/gethostbyaddr.py    | 28 ++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 40 deletions(-)
 create mode 100644 system/gethostbyaddr.py

diff --git a/system/PlcapiUrlScanner.py b/system/PlcapiUrlScanner.py
index e3e8ee8..71d9c73 100755
--- a/system/PlcapiUrlScanner.py
+++ b/system/PlcapiUrlScanner.py
@@ -10,6 +10,9 @@ import xmlrpc.client
 import traceback
 import ssl
 
+from gethostbyaddr import workaround_gethostbyaddr
+
+
 class PlcapiUrlScanner:
 
     # turns out the config has an ip but no name..
@@ -17,15 +20,14 @@ class PlcapiUrlScanner:
         self.auth = auth
         if not hostname and not ip:
             raise Exception("PlcapiUrlScanner needs _some_ input")
-        if hostname:
-            if not ip:
-                try:
-                    ip = socket.gethostbyname(hostname)
-                except:
-                    hostname = "{}.pl.sophia.inria.fr".format(hostname)
-                    ip = socket.gethostbyname(hostname)
-        else:
-            hostname=socket.gethostbyaddr(ip)[0]
+        if not hostname:
+            hostname = workaround_gethostbyaddr(ip)
+        elif hostname and not ip:
+            try:
+                ip = socket.gethostbyname(hostname)
+            except:
+                hostname = "{}.pl.sophia.inria.fr".format(hostname)
+                ip = socket.gethostbyname(hostname)
         self.hostname = hostname
         self.ip = ip
         self.verbose = verbose
diff --git a/system/TestPlc.py b/system/TestPlc.py
index 9555a99..57543d1 100644
--- a/system/TestPlc.py
+++ b/system/TestPlc.py
@@ -24,6 +24,8 @@ from PlcapiUrlScanner import PlcapiUrlScanner
 
 from TestBonding import TestBonding
 
+from gethostbyaddr import workaround_gethostbyaddr
+
 has_sfa_cache_filename="sfa-cache"
 
 # step methods must take (self) and return a boolean (options is a member of the class)
@@ -703,28 +705,6 @@ class TestPlc:
         for level in [ 'arch' ]:
             repo_url = os.path.dirname(repo_url)
 
-        ##########
-        # on the virsh containers, DNS resolution using gethostbyaddr
-        # won't work fine, for the hosts under .pl.sophia.inria.fr
-        # although these IPs can be reversed from virtually everywhere else
-        #
-        # this has started with something around fedora35 so I am suspecting python-3.10
-        #
-        # in any case, here's a quick and dirty workaround, as I have bumped my head
-        # against the screen for two good hours and not found any single clue
-        # about how to deal with this properly
-
-        import subprocess
-
-        def workaround_gethostaddr(ip):
-            command = f"host {ip} 8.8.8.8"
-            completed = subprocess.run(command, shell=True, capture_output=True)
-            pieces = completed.stdout.decode().split("domain name pointer ")
-            if len(pieces) == 2:
-                return pieces[1].replace(".\n", "")
-            else:
-                return None
-
         # invoke initvm (drop support for vs)
         script = "lbuild-initvm.sh"
         script_options = ""
@@ -734,15 +714,11 @@ class TestPlc:
         script_options += " -f {}".format(self.options.fcdistro)
         script_options += " -r {}".format(repo_url)
         vserver_name = self.vservername
-        try:
-            vserver_hostname = socket.gethostbyaddr(self.vserverip)[0]
-        except:
-            # read more above about this workaround
-            vserver_hostname = workaround_gethostaddr(self.vserverip)
-            if not vserver_hostname:
-                print("Cannot reverse lookup {}".format(self.vserverip))
-                print("This is considered fatal, as this might pollute the test results")
-                return False
+        vserver_hostname = workaround_gethostbyaddr(self.vserverip)
+        if not vserver_hostname:
+            print("Cannot reverse lookup {}".format(self.vserverip))
+            print("This is considered fatal, as this might pollute the test results")
+            return False
         script_options += " -n {}".format(vserver_hostname)
         create_vserver="{build_dir}/{script} {script_options} {vserver_name}".format(**locals())
         return self.run_in_host(create_vserver) == 0
diff --git a/system/gethostbyaddr.py b/system/gethostbyaddr.py
new file mode 100644
index 0000000..199fa59
--- /dev/null
+++ b/system/gethostbyaddr.py
@@ -0,0 +1,28 @@
+##########
+# on the virsh containers, DNS resolution using gethostbyaddr
+# won't work fine, for the hosts under .pl.sophia.inria.fr
+# although these IPs can be reversed from virtually everywhere else
+#
+# this has started with something around fedora35 so I am suspecting python-3.10
+#
+# in any case, here's a quick and dirty workaround, as I have bumped my head
+# against the screen for two good hours and not found any single clue
+# about how to deal with this properly
+
+import socket
+import subprocess
+
+def workaround_gethostbyaddr(ip):
+    try:
+        return socket.gethostbyaddr(ip)[0]
+    except:
+        # if that fails, try again using the `host` command
+        # which - surprisingly enough - works quite fine
+        # inside the containers
+        command = f"host {ip} 8.8.8.8"
+        completed = subprocess.run(command, shell=True, capture_output=True)
+        pieces = completed.stdout.decode().split("domain name pointer ")
+        if len(pieces) == 2:
+            return pieces[1].replace(".\n", "")
+        else:
+            return None
-- 
2.43.0