X-Git-Url: http://gitweb.michael.orlitzky.com/?p=haeredes.git;a=blobdiff_plain;f=src%2FMain.hs;h=c9356bfd9318de6d96c279d0bd9dd0608fe9b332;hp=6b276b7980b9b5687493f6b72ab46590d5fb9b9d;hb=fdf3555b3e8a1f937172baa691ca219b0e54a35f;hpb=73848fa79919aa6c9da8fb9fb87e3eb21b7672d4

diff --git a/src/Main.hs b/src/Main.hs
index 6b276b7..c9356bf 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,64 +1,86 @@
-module Main
+module Main (main)
 where
 
 import Control.Concurrent.ParallelIO.Global (
-  parallel,
+  parallelInterleaved,
   stopGlobalPool )
 import Control.Monad (unless)
 import qualified Data.ByteString.Char8 as BS (
   getContents,
   pack,
   words )
-import Data.List ((\\))
-import Data.String.Utils (join)
+import Data.List ( (\\), intersperse, sort )
 import Network.DNS (
+  DNSError(NameError),
   Domain,
   FileOrNumericHost(RCHostName),
-  ResolvConf(resolvInfo),
+  ResolvConf(resolvInfo, resolvTimeout),
   defaultResolvConf,
   makeResolvSeed,
+  normalize,
+  normalizeCase,
   withResolver )
-import System.Exit (ExitCode(..), exitWith)
+import System.Exit (ExitCode(ExitFailure), exitWith)
 import System.IO (hPutStrLn, stderr)
 
-
-import CommandLine (Args(..), get_args)
+import CommandLine (
+   Args(NS,MX,delegates,no_append_root,server,timeout),
+   get_args)
 import DNS (
   LookupResult,
   lookupMX',
   lookupNS',
-  normalize,
-  normalize_case,
   resolve_address )
 import ExitCodes (exit_bad_server)
+import Timeout (Timeout(seconds))
+
+
+-- | Given a list of delegates, report results for this
+--   'LookupResult'.
+--
+--   If there's an empty list in the second component, there were no
+--   query results, so we report that the domain was not delegated. If
+--   there were some results and there are leftovers (after removing
+--   the delegates), we report those as well.
+--
+--   Before processing, all names are normalized using the supplied
+--   function @normalize_function@. Ideally this should be the same
+--   function applied to the user-input names.
+--
+report :: [Domain] -- ^ The list of @delgts@
+       -> (Domain -> Domain) -- ^ Domain name normalization function,
+                             --   @normalize_function@.
+       -> LookupResult
+       -> IO ()
+
+-- If the lookup succeeded but there were no results, report that the
+-- domain is not delegated. Note that the behavior of the DNS library
+-- changed with regard to this at some point: we used to get back
+-- a "success," but with an empty list of results. Now a NameError
+-- (which is not actually an error!) is returned.
+report _ _ (d, Left NameError) =
+  putStrLn $ "Domain " ++ (show d) ++ " not delegated."
 
+-- If the lookup resulted in some other DNS error, we just ignore the
+-- whole thing.
+report _ _ (_, Left _) = return ()
 
--- | Report results for this LookupResult. If there's a Nothing in the
---   second component, there were no query results, so we report that
---   the domain was not delegated. If there were some results and
---   there are leftovers (after "cleaning"), we report those as well.
-report :: LookupResult -> IO ()
-report (d, Nothing) =
-  putStrLn $ "Domain " ++ (show d) ++ " not delegated."
-report (d, Just leftovers) =
+-- Otherwise, subtract our delegates from the list of results and
+-- report the leftovers.
+report delgts normalize_function (d, Right raw_hosts) = do
+  let nrml_hosts = map normalize_function raw_hosts
+  -- Sort the leftovers so that we can test the expected output.
+  let leftovers = sort (nrml_hosts \\ delgts)
   unless (null leftovers) $
     putStrLn $ "Domain " ++
                (show d) ++
                " delegates somewhere else: " ++
                (join " " (map show leftovers))
-
-
--- | "Clean" a lookup result by subtracting out the list of delegates.
---   There shouldn't be anything left over. If there were no lookup
---   results, we leave the Nothing in place so that 'report' can
---   pattern match on it.
-clean :: [Domain] -- ^ List of delegates, @ds@
-      -> LookupResult
-      -> LookupResult
-clean _ p@(_, Nothing) = p
-clean delgts (d, Just targets) =
-  (d, Just $ targets \\ delgts)
-
+  where
+    -- Create one big string by joining together a list of smaller
+    -- strings and placing a delimiter between them.
+    join :: String -> [String] -> String
+    join delimiter strings = concat (intersperse delimiter strings)
 
 
 main :: IO ()
@@ -76,36 +98,50 @@ main = do
 
   let normalize_function =
         if (no_append_root cfg)
-        then normalize_case
+        then normalizeCase
         else normalize
 
   -- Normalize the given names and delegates
   let nrml_domains   = map normalize_function raw_domains
   let nrml_delegates = map normalize_function raw_delegates
 
-  rc <- case (server cfg) of
-          Nothing -> return defaultResolvConf
-          Just s -> do
-            s' <- resolve_address s
-            case s' of
-              Nothing -> do
-                hPutStrLn stderr ("Bad DNS server or lookup error: " ++ s)
-                exitWith (ExitFailure exit_bad_server)
-              Just s'' ->
-                return $ defaultResolvConf { resolvInfo =
-                                               RCHostName (show s'') }
-
+  rc' <- case (server cfg) of
+           Nothing -> return defaultResolvConf
+           Just s -> do
+             s' <- resolve_address s
+             case s' of
+               Left err -> do
+                 let errmsg = show err
+                 hPutStrLn stderr ("Bad DNS server or lookup error: " ++ errmsg)
+                 exitWith (ExitFailure exit_bad_server)
+               Right []  -> do
+                 hPutStrLn stderr ("Hostname " ++ s ++ " has no 'A' records.")
+                 exitWith (ExitFailure exit_bad_server)
+               Right (srv:_) ->
+                 return $ defaultResolvConf { resolvInfo =
+                                                RCHostName (show srv) }
+
+  -- Set the timeout from the command line. The resolvTimeout field is
+  -- in microseconds, so we multiply by one million.
+  let a_million = 1000 * 1000 :: Int
+  let rc = rc' { resolvTimeout = a_million * seconds (timeout cfg) }
   rs <- makeResolvSeed rc
 
   let lookup_function = case cfg of
                           NS{} -> lookupNS'
                           MX{} -> lookupMX'
 
-  _ <- withResolver rs $ \resolver -> do
-         -- Bad stuff happens if we try to run these lookups in parallel
-         -- instead of the reports.
-         records <- mapM (lookup_function resolver) nrml_domains
-         let cleaned_records = map (clean nrml_delegates) records
-         parallel (map report cleaned_records)
+  let lookup' d = withResolver rs $ \resolver ->
+                    lookup_function resolver d
+
+  -- Construct a list of [IO whatever]. The withResolver calls
+  -- are the ones that should be run in parallel.
+  let actions = map lookup' nrml_domains
+
+  -- Run the lookup actions in parallel.
+  results <- parallelInterleaved actions
+
+  -- Output the results.
+  _ <- mapM (report nrml_delegates normalize_function) results
 
   stopGlobalPool