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sourcecode:
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module Network.CPNSD
where
import Control.Monad ( unless )
import System.Environment ( getArgs )
import Data.Time ( calendarTimeToString, getLocalTime )
import System.Directory ( doesFileExist )
import System.IO ( hFlush, hPutStrLn, stderr )
import System.Process ( getPID, system )
import Network.CPNS
import Network.CPNS.Config
--- Main function for CPNS demon. Check arguments and execute command.
main :: IO ()
main = do
args <- getArgs
case args of
["serve"] -> cpnsStart
["start"] -> startServerIfNecessary
["stop"] -> stopServer
["status"] -> cpnsStatus
["log"] -> do logfile <- getLogFile
readFile logfile >>= putStr
_ -> putErrLn $ "ERROR: Illegal arguments: " ++ unwords args ++ "\n" ++
"Allowed arguments: start | stop | serve | status | log"
--- Start the Curry Port Name Server demon, if it is not already
--- started on this machine:
startServerIfNecessary :: IO ()
startServerIfNecessary = do
alive <- cpnsAlive "localhost"
unless alive $ do
putErrLn "CPNS demon seems to be aborted. I try to restart it..."
startServer
startServer :: IO ()
startServer = do
lockfile <- getStartupLockFile
lfc <- system $ "lockfile-create --lock-name " ++ lockfile
if lfc == 0
then do
putErrLn "Starting demon for Curry Port Name Server..."
logfile <- getLogFile
exlogfile <- doesFileExist logfile
unless exlogfile $ do
-- create log file with correct access rights:
system $ "touch " ++ logfile
-- make log file accessible for everybody:
system $ "chmod -f 666 " ++ logfile
return ()
putErrLn $ "Log information in file '" ++ logfile ++ "'"
ctime <- getLocalTime
appendFile logfile $
"CPNS demon started at " ++ calendarTimeToString ctime ++ "\n"
-- start CPNSD in server mode:
cpnsbin <- getCPNSD
system $ "nohup \"" ++ cpnsbin ++ "\" serve >> " ++ logfile ++ " 2>&1 &"
lockFileCreateAndRemove lockfile
putErrLn "CPNS demon started."
else do
putErrLn "CPNS demon seems already started by another process"
putErrLn $ "If this is not the case, delete file '" ++ lockfile ++ "'"
lockFileCreateAndRemove lockfile
where
-- wait for lockfile deletion by CPNS demon startup:
lockFileCreateAndRemove lockfile = do
system $ "lockfile-create --lock-name " ++ lockfile
system $ "lockfile-remove --lock-name " ++ lockfile
return ()
--- Terminate the Curry Port Name Server demon, if it is not already terminated.
stopServer :: IO ()
stopServer = do
lockfile <- getStartupLockFile
system $ "/bin/rm -f " ++ lockfile -- just to be sure
-- test whether the server process is still alive:
alive <- cpnsAlive "localhost"
if alive then cpnsStop
else putErrLn "CPNS demon does not seem to be alive"
putErrLn :: String -> IO ()
putErrLn s = hPutStrLn stderr s >> hFlush stderr
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