> module Main (main) where > import IO > import Maybe > import Exception > import Posix > import System > import GetOpt > import MD5 > data Flag = Verbose | Binary {- not implemented -} | Check String > | Test deriving Eq main works out what need to be done and calls the appropriate function to do it > main :: IO() > main = do args <- System.getArgs > (opts, files) <- md5sum_opts args > if or $ map ((==) Test) opts > then md5test > else case is_check opts of > Nothing > -> if files == [] > then do (str, len) <- read_stdin > putStr (md5_size (8 * len) str) > >> putStr "\n" > else foldr (\x y -> md5_file x >> y) > (putStr "") files > Just fn -> check (is_verbose opts) fn Read everything from stdin and return it along with it's length > read_stdin :: IO (String, Integer) > read_stdin = do maybeData <- tryAllIO $ fdRead stdInput 1024 > case maybeData of > Left _ -> return ("", 0) > Right (this, len) > -> do (rest, r_len) <- read_stdin > return $ (this ++ rest, toInteger len + r_len) MD5 a file and print the result > md5_file :: String -> IO() > md5_file file = do maybe_content <- tryAllIO $ readFile file > maybe_fs <- tryAllIO $ getFileStatus file > case (maybe_content, maybe_fs) of > (Right content, Right fs) -> > putStr (md5_size size content) > >> putStr " " > >> putStr file > >> putStr "\n" > where size = 8 * fileSize fs > (_, Left _) -> putErr file >> putErr ": No such file or directory.\n" > (Left _, _) -> do ec <- getErrorCode > if ec == permissionDenied > then putErr file >> putErr ": Permission denied\n" > else putErr "md5sum: error reading " >> putErr file >> putErr "\n" Run the test suite > md5test :: IO() > md5test = foldr f (putStr "") l > where f (str, hash) so_far > = putStr "Doing " >> putStr (show str) >> putStr "\n" > >> putStr "Should be " >> putStr hash >> putStr "\n" > >> putStr "Got " >> putStr (md5 str) >> putStr "\n\n" > >> so_far > l = [("", "d41d8cd98f00b204e9800998ecf8427e"), > ("a", "0cc175b9c0f1b6a831c399e269772661"), > ("abc", "900150983cd24fb0d6963f7d28e17f72"), > ("message digest", "f96b697d7cb7938d525a2f31aaf161d0"), > ("abcdefghijklmnopqrstuvwxyz", > "c3fcd3d76192e4007dfb496cca67e13b"), > ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", > "d174ab98d277d9f5a5611c2c9f419d9f"), > ("12345678901234567890123456789012345678901234567890123456789012345678901234567890", > "57edf4a22be3c955ac49da2e2107b67a")] Given a file with a list of checksums, check all the checksums > check :: Bool -> String -> IO() > check v f = > do maybe_l <- tryAllIO $ get_list f > case maybe_l of > Left _ -> > do ec <- getErrorCode > if ec == permissionDenied > then putErr f >> putErr ": Permission denied\n" > else putErr f >> putErr ": No such file or directory\n" > Right l -> > do (_, number, broken) > <- foldl (checkhash v) (return (15, 0, 0)) l > if v && broken > 0 then putErr "md5sum: " > >> putErr (show broken) > >> putErr " of " > >> putErr (show number) > >> putErr "file(s) fail MD5 check\n" > else putStr "" Given a (hash, file) tuple, check the hash is correct for that file and update the longest length so far and counts > checkhash :: Bool -> IO (Int, Int, Int) -> (String, String) -> IO (Int, Int, Int) > checkhash v io_l_n_b (h, f) = > do (len, number, broken) <- io_l_n_b > maybe_content <- tryAllIO $ readFile f > maybe_fs <- tryAllIO $ getFileStatus f > let len' = if length f >= len - 1 then length f + 1 > else len > let io_fn = putErr f >> putErr (replicate (len' - length f) ' ') > case (maybe_content, maybe_fs) of > (Right content, Right fs) -> > let h' = md5_size (8 * (toInteger $ fileSize fs)) content in > if h == h' > then if v > then do _ <- io_fn >> putErr "OK\n" > return (len', number + 1, broken) > else return (len', number + 1, broken) > else do _ <- if v > then io_fn >> putErr "FAILED\n" > else putErr "md5sum: MD5 check failed for '" > >> putErr f >> putErr "'\n" > return (len', number + 1, broken + 1) > (_, _) -> do _ <- (if v then io_fn >> putErr "md5sum: Can't open " > else putErr "md5sum: Can't open ") > >> putErr f > >> putErr "\n" > return (len', number, broken) Given a filename for checking, get the list of hash, filename tuples > get_list :: String -> IO [(String, String)] > get_list f = do h <- openFile f ReadMode > let content = parse h > {- hClose h -} > content Do the work for the above > parse :: Handle -> IO [(String, String)] > parse h = do eof <- hIsEOF h > if eof > then return [] > else do line <- hGetLine h > rest <- parse h > let hash = take 32 line > let filename = drop 34 line > if filename /= "" && is_hash hash > then return $ (hash, filename):rest > else return rest If the String is a valid hash (the length is assumed to be correct) return True, else False > is_hash :: String -> Bool > is_hash "" = True > is_hash (c:cs) = if (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') > then is_hash cs > else False putStr for errors > putErr :: String -> IO() > putErr = hPutStr stderr ===== Options ===== > options :: [OptDescr Flag] > options = > [Option ['c'] [] (ReqArg Check "Check") "check message digests (default is generate)", > Option ['v'] [] (NoArg Verbose) "verbose, print file names when checking", > Option ['b'] [] (NoArg Binary) "(ignored)", > Option ['t'] [] (NoArg Test) "test the code is functioning correctly"] > md5sum_opts :: [String] -> IO ([Flag], [String]) > md5sum_opts argv = > case (getOpt Permute options argv) of > (o,n,[] ) -> return (o,n) > (_,_,errs) -> fail (concat errs ++ usageInfo header options ++ footer) > where header = "usage: md5sum [-btv] [-c [file]] | [file...]\nGenerates or checks MD5 Message Digests" > footer = "The input for -c should be the list of message digests and file names\nthat is printed on stdout by this program when it generates digests." > is_check :: [Flag] -> Maybe String > is_check [] = Nothing > is_check (Check s:_) = Just s > is_check (_:os) = is_check os > is_verbose :: [Flag] -> Bool > is_verbose = foldr (\x y -> if x == Verbose then True else y) False