X-Git-Url: http://gitweb.michael.orlitzky.com/?p=haeredes.git;a=blobdiff_plain;f=src%2FMain.hs;h=70fa2f57c842ebb34c96e2e268070065b2488530;hp=6b276b7980b9b5687493f6b72ab46590d5fb9b9d;hb=e862342c38e41176a7ab300b6d7ed03cf0ffd6b2;hpb=73848fa79919aa6c9da8fb9fb87e3eb21b7672d4

diff --git a/src/Main.hs b/src/Main.hs
index 6b276b7..70fa2f5 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -2,7 +2,7 @@ module Main
 where
 
 import Control.Concurrent.ParallelIO.Global (
-  parallel,
+  parallelInterleaved,
   stopGlobalPool )
 import Control.Monad (unless)
 import qualified Data.ByteString.Char8 as BS (
@@ -14,9 +14,11 @@ import Data.String.Utils (join)
 import Network.DNS (
   Domain,
   FileOrNumericHost(RCHostName),
-  ResolvConf(resolvInfo),
+  ResolvConf(resolvInfo, resolvTimeout),
   defaultResolvConf,
   makeResolvSeed,
+  normalize,
+  normalizeCase,
   withResolver )
 import System.Exit (ExitCode(..), exitWith)
 import System.IO (hPutStrLn, stderr)
@@ -27,20 +29,36 @@ import DNS (
   LookupResult,
   lookupMX',
   lookupNS',
-  normalize,
-  normalize_case,
   resolve_address )
 import ExitCodes (exit_bad_server)
-
-
--- | 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) =
+import Timeout (Timeout(..))
+
+
+-- | 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.
+--
+report :: [Domain] -- ^ The list of @delgts@
+       -> LookupResult
+       -> IO ()
+
+-- If the lookup resulted in a DNS error, we just ignore the whole
+-- thing.
+report _ (_, Left _) = return ()
+
+-- If the lookup succeeded but there were no results, report that the
+-- domain is not delegated.
+report _ (d, Right []) =
   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 (d, Right hosts) = do
+  let leftovers = hosts \\ delgts
   unless (null leftovers) $
     putStrLn $ "Domain " ++
                (show d) ++
@@ -48,19 +66,6 @@ report (d, Just leftovers) =
                (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)
-
-
-
 main :: IO ()
 main = do
   cfg <- get_args
@@ -76,36 +81,49 @@ 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 rc = rc' { resolvTimeout = 1000 * 1000 * 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) results
 
   stopGlobalPool