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module CPNS(registerPort,getPortInfo,unregisterPort,
cpnsStart,cpnsStop,cpnsShow,cpnsAlive,main) where
import Char
import Distribution(installDir)
import FilePath((</>))
import IO
import List(delete,intersperse)
import Profile
import ReadShowTerm
import Socket
import System
import Time
cpnsSocket :: Int
cpnsSocket = 8767
cpnsTimeOut :: Int
cpnsTimeOut = 3000
data CPNSMessage = Terminate
| Ping
| Register String Int Int Int
| GetRegister String
| Unregister String
| ShowRegistry
cpnsStartupLockfile :: String
cpnsStartupLockfile = "/tmp/CurryPNSD.lock"
cpnsStart :: IO ()
cpnsStart = catch startup
(\_ -> putStrLn "FAILURE occurred during startup!" >>
deleteStartupLockfile >>
return Nothing) >>=
maybe done (cpnsServer [])
where
deleteStartupLockfile = do
putStrLn $ "Removing startup lock file \""++cpnsStartupLockfile++"\"..."
system $ "rm -f "++cpnsStartupLockfile
done
startup = do
putStrLn $ "Starting Curry Port Name Server on port " ++
show cpnsSocket ++ "..."
socket <- listenOn cpnsSocket
deleteStartupLockfile
pid <- getPID
putStrLn $ "Curry Port Name Server is ready (PID: "++show pid++")."
return (Just socket)
cpnsServer :: [(String,Int,Int,Int)] -> Socket -> IO ()
cpnsServer regs socket = do
(chost,stream) <- socketAccept socket
serveRequest chost stream
where
doIfLocalHost rhost action = do
hostname <- getHostname
if rhost `elem` ["localhost","localhost.localdomain",hostname]
|| take 8 rhost == "127.0.0."
then action
else do putStrLn $ "Illegal request received from host: " ++ rhost
cpnsServer regs socket
serveRequest rhost h = do
msg <- readMsgLine h
either
(\line -> do putStrLn $ "ERROR: Illegal message:\n" ++ line
cpnsServer regs socket )
(\m -> case m of
Terminate -> doIfLocalHost rhost $ do
hClose h
putStrLn "CPNS demon terminated."
Ping -> do
hPutStrLn h (showQTerm ())
hClose h
cpnsServer regs socket
Register pname pid sn pn -> doIfLocalHost rhost $ do
(ack, newregs) <- tryRegisterPortName regs pname pid sn pn
hPutStrLn h (showQTerm ack)
hClose h
cpnsServer newregs socket
GetRegister pname -> do
(newregs,pinfo) <- getRegisteredPortName regs pname
hPutStrLn h (showQTerm pinfo)
hClose h
cpnsServer newregs socket
Unregister pname -> doIfLocalHost rhost $ do
newregs <- unregisterPortName regs pname
hClose h
cpnsServer newregs socket
ShowRegistry -> doIfLocalHost rhost $ do
putStrLn "Currently registered port names:"
newregs <- showAndCleanRegs regs
hFlush stdout
hClose h
cpnsServer newregs socket )
msg
tryRegisterPortName :: [(String,Int,Int,Int)] -> String -> Int -> Int -> Int
-> IO (Bool, [(String, Int, Int, Int)])
tryRegisterPortName regs name pid sn pn = do
let nameregs = filter (\(n,_,_,_)->name==n) regs
ack <- if null nameregs
then return True
else let (_,pid',_,_) = head nameregs in
if pid'>0 && pid'/=pid
then doesProcessExists pid' >>= \pex -> return (not pex)
else return True
ctime <- getLocalTime
putStrLn $ "Register port \""++name++"\": pid "++show pid++
" / socket "++show sn++
" / number "++show pn ++ " at " ++ calendarTimeToString ctime
let newregs = (name,pid,sn,pn) : filter (\ (n,_,_,_)->name/=n) regs
printMemInfo newregs
hFlush stdout
return (ack, newregs)
unregisterPortName :: [(String,Int,Int,Int)] -> String
-> IO [(String,Int,Int,Int)]
unregisterPortName regs name = do
ctime <- getLocalTime
putStrLn $ "Unregister port \""++name++"\" at "++calendarTimeToString ctime
let newregs = filter (\ (n,_,_,_)->name/=n) regs
printMemInfo newregs
hFlush stdout
return newregs
getRegisteredPortName :: [(String,Int,Int,Int)] -> String
-> IO ([(String,Int,Int,Int)],(Int,Int))
getRegisteredPortName regs pname =
let nameregs = filter (\(n,_,_,_)->pname==n) regs in
if null nameregs
then return (regs,(0,0))
else let (_,pid,sn,pn) = head nameregs in
if pid>0
then doesProcessExists pid >>= \pex ->
if pex
then return (regs,(sn,pn))
else
return (delete (head nameregs) regs, (0,0))
else return (regs,(sn,pn))
showAndCleanRegs :: [(String,Int,Int,Int)] -> IO [(String,Int,Int,Int)]
showAndCleanRegs regs = do
newreglist <- mapIO checkAndShow regs
return (concat newreglist)
where
checkAndShow reg@(n,pid,sn,pn) = do
pidexist <- doesProcessExists pid
if pidexist
then do putStrLn $ n++": pid "++show pid++
" / socket "++show sn++" / number "++show pn
return [reg]
else return []
printMemInfo :: [(String,Int,Int,Int)] -> IO ()
printMemInfo regs = do
pinfos <- getProcessInfos
putStrLn ("NumRegs: " ++ show (length regs) ++ ", " ++ showMemInfo pinfos)
doesProcessExists :: Int -> IO Bool
doesProcessExists pid = do
status <- system("test -z \"`ps -p "++show pid++" | fgrep "++show pid++"`\"")
return (status>0)
readMsgLine :: Handle -> IO (Either String a)
readMsgLine handle = do
line <- hGetLine handle
case readsQTerm line of
[(msg,rem)] -> return (if all isSpace rem then Right msg else Left line)
_ -> return (Left line)
doIfAlive :: String -> IO a -> IO a
doIfAlive host action = do
alive <- cpnsAlive cpnsTimeOut host
if not alive
then error $ "Curry port name server at host \""++host++
"\" is not reachable (timeout after "++show cpnsTimeOut++
" ms)!"
else action
sendToLocalCPNS :: CPNSMessage -> IO ()
sendToLocalCPNS msg = doIfAlive "localhost" $ do
h <- connectToSocket "localhost" cpnsSocket
hPutStrLn h (showQTerm msg)
hClose h
cpnsShow :: IO ()
cpnsShow = sendToLocalCPNS ShowRegistry
cpnsStop :: IO ()
cpnsStop = sendToLocalCPNS Terminate
cpnsTryGetAnswer :: String -> CPNSMessage -> IO _
cpnsTryGetAnswer host msg = catch tryGetAnswer connectError
where
tryGetAnswer = do
h <- connectToSocket host cpnsSocket
hPutStrLn h (showQTerm msg)
hFlush h
ready <- hWaitForInput h cpnsTimeOut
if ready
then do
answer <- readMsgLine h
hClose h
either (\line -> error $ "cpnsTryGetAnswer: Illegal answer: " ++ line)
return
answer
else failed
connectError _ = error $ "Curry port name server at host \""++host++
"\" is not reachable!"
registerPort :: String -> Int -> Int -> IO ()
registerPort pname sn pn = do
startCPNSDIfNecessary
pid <- getPID
ack <- cpnsTryGetAnswer "localhost" (Register pname pid sn pn)
if ack then done
else putStrLn ("WARNING: Port name '"++pname++"' already registered!")
getPortInfo :: String -> String -> IO (Int,Int)
getPortInfo pname host = cpnsTryGetAnswer host (GetRegister pname)
unregisterPort :: String -> IO ()
unregisterPort pname = sendToLocalCPNS (Unregister pname)
cpnsAlive :: Int -> String -> IO Bool
cpnsAlive timeout host = catch tryPingCPNS (\_ -> return False)
where
tryPingCPNS = do
h <- connectToSocket host cpnsSocket
hPutStrLn h (showQTerm Ping)
hFlush h
answer <- hWaitForInput h timeout
hClose h
return answer
startCPNSDIfNecessary :: IO ()
startCPNSDIfNecessary = do
system $ installDir </> "currytools" </> "cpns" </> "start"
done
main :: IO ()
main = do
args <- getArgs
case args of
["start"] -> cpnsStart
["stop"] -> cpnsStop
["show"] -> cpnsShow
_ -> putStrLn $ "ERROR: Illegal arguments: " ++
concat (intersperse " " args) ++ "\n" ++
"Allowed arguments: start|stop|show"
|