X-Git-Url: http://gitweb.michael.orlitzky.com/?p=haeredes.git;a=blobdiff_plain;f=src%2FMain.hs;h=89d2cd56d1a2aeaca07420d403e2e29da1e7abfe;hp=d425734c275404e24310edb650ac33c9b4fe0b67;hb=8107db78784648b609c70f1d448764fc6c22f0ef;hpb=70dffd6160208adf2c1c5746924c100cb0ffcb2e

diff --git a/src/Main.hs b/src/Main.hs
index d425734..89d2cd5 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,45 +1,81 @@
-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 )
 import Network.DNS (
   Domain,
   FileOrNumericHost(RCHostName),
-  ResolvConf(resolvInfo),
+  ResolvConf(resolvInfo, resolvTimeout),
   defaultResolvConf,
-  lookupNS,
   makeResolvSeed,
+  normalize,
+  normalizeCase,
   withResolver )
-
-import CommandLine (Args(..), get_args)
-import DNS (normalize)
-
-report :: (Domain, Maybe [Domain]) -> IO ()
-report (d, Nothing) =
+import System.Exit (ExitCode(ExitFailure), exitWith)
+import System.IO (hPutStrLn, stderr)
+
+import CommandLine (
+   Args(NS,MX,delegates,no_append_root,server,timeout),
+   get_args)
+import DNS (
+  LookupResult,
+  lookupMX',
+  lookupNS',
+  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 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) =
-  if null leftovers
-  then return ()
-  else putStrLn $ "Domain " ++
-                  (show d) ++
-                  " delegates somewhere else: " ++
-                  (join " " (map show leftovers))
-
-clean :: [Domain] -- ^ List of delegates, @ds@
-      -> (Domain, Maybe [Domain]) -- ^ Pairs of (domain name, lookup result)
-      -> (Domain, Maybe [Domain])
-clean _ p@(_, Nothing) = p
-clean ds (d, Just targets) =
-  (d, Just $ targets \\ ds)
+
+-- 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
+  let leftovers = nrml_hosts \\ delgts
+  unless (null leftovers) $
+    putStrLn $ "Domain " ++
+               (show d) ++
+               " delegates somewhere else: " ++
+               (join " " (map show leftovers))
+  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 ()
@@ -55,29 +91,52 @@ main = do
   -- Convert these to ByteStrings.
   let raw_delegates = map BS.pack (delegates cfg)
 
+  let normalize_function =
+        if (no_append_root cfg)
+        then normalizeCase
+        else normalize
+
   -- Normalize the given names and delegates
-  let nrml_domains   = map normalize raw_domains
-  let nrml_delegates = map normalize raw_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
+               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 rc = case (server cfg) of
-             Nothing -> defaultResolvConf
-             Just s -> defaultResolvConf { resolvInfo = RCHostName s }
+  let lookup_function = case cfg of
+                          NS{} -> lookupNS'
+                          MX{} -> lookupMX'
 
-  rs <- makeResolvSeed rc
-  withResolver rs $ \resolver -> do
-    -- This function keeps the domain matches with its NS records.
-    let lookupNS' = \d -> (lookupNS resolver d) >>= (return . ((,) d))
-
-    -- Bad stuff happens if we try to run these lookups in parallel
-    -- instead of the reports.
-    domains_ns <- mapM lookupNS' nrml_domains
-    let cdns = map (clean nrml_delegates) domains_ns
-
-    _ <- case cfg of
-           (NS _ _) ->
-             -- We're only checking NS records, so report what we found.
-             parallel (map report cdns)
-           (MX _ _) ->
-             return [()]
-
-    stopGlobalPool
+  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