Add option to use resolv.conf (thanks James Cloos)

 * This allows one to use a recursor for lookups instead of letting libunbound
   do the recursion

diff --git a/swede b/swede
index 643c079d55107dc97c3792040a6d6589e6971c87..4be39b51e1c7d060ffe765f8e3def42d785ece0e 100755 (executable)
--- a/swede
+++ b/swede
@@ -109,8 +109,12 @@ def getVerificationErrorReason(num):
 
 def getRecords(hostname, rrtype='A', secure=True):
        """Do a lookup of a name and a rrtype, returns a list of binary coded strings. Only queries for rr_class IN."""
+       global resolvconf
        ctx = unbound.ub_ctx()
        ctx.add_ta_file('root.key')
+       # Use the local cache
+       if resolvconf and os.path.isfile(resolvconf):
+               ctx.resolvconf(resolvconf)
 
        if type(rrtype) == str:
                if 'RR_TYPE_' + rrtype in dir(unbound):
@@ -348,6 +352,7 @@ if __name__ == '__main__':
        #parser.add_argument('-4', dest='ipv4', action='store_true',help='use ipv4 networking only')
        #parser.add_argument('-6', dest='ipv6', action='store_true',help='use ipv6 networking only')
        parser.add_argument('--insecure', action='store_true', default=False, help='Allow use of non-dnssec secured answers')
+       parser.add_argument('--resolvconf', metavar='/PATH/TO/RESOLV.CONF', action='store', default='', help='Use a recursive resolver from resolv.conf')
        parser.add_argument('-v', '--version', action='version', version='%(prog)s v0.1', help='show version and exit')
        parser.add_argument('host', metavar="hostname")
 
@@ -372,6 +377,16 @@ if __name__ == '__main__':
        if args.host[-1] != '.':
                args.host += '.'
 
+       global resolvconf
+       if args.resolvconf:
+               if os.path.isfile(args.resolvconf):
+                       resolvconf = args.resolvconf
+               else:
+                       print >> sys.stdout, '%s is not a file. Unable to use it as resolv.conf' % args.resolvconf
+                       sys.exit(1)
+       else:
+               resolvconf = None
+
        # not operations are fun!
        secure = not args.insecure