-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 ()
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
projects / haeredes.git / blobdiff