[Pydns-developer] [ pydns-Bugs-1644000 ] Fails to trap socket.error when network is not available

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Bugs item #1644000, was opened at 2007-01-24 21:27
Message generated for change (Comment added) made by kitterma
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Category: None
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 3
Private: No
Submitted By: Scott Kitterman (kitterma)
Assigned to: Nobody/Anonymous (nobody)
Summary: Fails to trap socket.error when network is not available

Initial Comment:
To replicate this problem, I first stopped networking (sudo sh /etc/init.d/networking stop) and then executed a python program that calls python-dns. Here is the python-dns part of the stack trace:

  File "/var/lib/python-support/python2.5/DNS/Base.py", line 173, in req
    self.sendUDPRequest(server)
  File "/var/lib/python-support/python2.5/DNS/Base.py", line 189, in sendUDPRequest
    self.conn()
  File "/var/lib/python-support/python2.5/DNS/Base.py", line 137, in conn
    self.s.connect((self.ns,self.port))
  File "<string>", line 1, in connect
socket.error: (101, 'Network is unreachable')

Looking at the code in Base.py, socket errors on not trapped unlike other errors in the file.

----------------------------------------------------------------------

>Comment By: Scott Kitterman (kitterma)
Date: 2007-11-18 21:39

Message:
Logged In: YES 
user_id=1300068
Originator: YES

Fixed in 2.3.1

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Comment By: Scott Kitterman (kitterma)
Date: 2007-01-24 21:30

Message:
Logged In: YES 
user_id=1300068
Originator: YES

Here's the fix for this issue (which was Ubuntu bug #80360) and Debian bug
#378991

--- python-dns-2.3.0.orig/DNS/Base.py
+++ python-dns-2.3.0/DNS/Base.py
@@ -29,7 +29,8 @@
         if not line or line[0]==';' or line[0]=='#':
             continue
         fields=string.split(line)
-        if len(fields) == 0: 
+        #Fix Debian bug #378991
+        if len(fields) < 2: 
             continue
         if fields[0]=='domain':
             defaults['domain']=fields[1]
@@ -169,10 +170,14 @@
               1, 0, 0, 0)
         m.addQuestion(qname, qtype, Class.IN)
         self.request = m.getbuf()
-        if protocol == 'udp':
-            self.sendUDPRequest(server)
-        else:
-            self.sendTCPRequest(server)
+        #Trap socket.error - Fix Ubuntu bug #80360
+        try:
+            if protocol == 'udp':
+                self.sendUDPRequest(server)
+            else:
+                self.sendTCPRequest(server)
+        except socket.error, reason:
+            raise DNSError, reason
         if self.async:
             return None
         else:

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