fetchmailconf.py: hostname qualification fixup

If socket.gethostname() returns a qualified name, don't look further,
to match fetchmail's behaviour - in case of an FQDN /etc/hostname
with broken /etc/hosts, this helps us survive.

Else, call socket.getfqdn() and not gethostbyaddr() in an attempt to qualify
the hostname.

Failing that, print an error message that tells the user to fix
/etc/hosts, which has this canonical format:
10.9.8.7 host.example.org host
on the assumption that that line and DNS might both be broken.

Gitlab, fixes #12 reported by Sergey Alirzaev - the prior attempt fixed
the wrong place (which also needed fixing).

Bump version to 1.63.

1 files changed, 7 insertions, 2 deletions

diff --git a/fetchmailconf.py b/fetchmailconf.py
index e6b6ae05..07596b17 100755
--- a/fetchmailconf.py
+++ b/fetchmailconf.py
@@ -29,7 +29,7 @@ import subprocess
 from tkinter import *
 from tkinter.dialog import *
 
-VERSION = "1.62"
+VERSION = "1.63"
 
 MIN_PY = (2, 7, 13)
 if sys.version_info < MIN_PY:
@@ -2204,7 +2204,12 @@ COPYING in the source or documentation directory for details.""")
             sys.exit(0)
 
     # Get client host's FQDN
-    hostname = socket.gethostbyaddr(socket.gethostname())[0]
+    hostname = socket.gethostname()
+    if not '.' in hostname:
+        hostname = socket.getfqdn(hostname)
+    # still unqualified?
+    if not '.' in hostname:
+        sys.exit('Cannot qualify my own hostname, "{}".\nFix /etc/hosts, see man 5 hosts, or add the host to DNS.'.format(hostname))
 
     # Compute defaults
     ConfigurationDefaults = Configuration()