diff options
| -rw-r--r-- | Utility/Daemon.hs | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/Utility/Daemon.hs b/Utility/Daemon.hs index 35b485983..3417cb5c6 100644 --- a/Utility/Daemon.hs +++ b/Utility/Daemon.hs @@ -19,9 +19,12 @@ import System.Posix - When successful, does not return. -} daemonize :: Fd -> Maybe FilePath -> Bool -> IO () -> IO () daemonize logfd pidfile changedirectory a = do + maybe noop checkalreadyrunning pidfile _ <- forkProcess child1 out where + checkalreadyrunning f = maybe noop (const $ alreadyRunning) + =<< checkDaemon f child1 = do _ <- createSession _ <- forkProcess child2 @@ -53,15 +56,17 @@ lockPidFile file = do { trunc = True } locked' <- catchMaybeIO $ setLock fd' (WriteLock, AbsoluteSeek, 0, 0) case (locked, locked') of - (Nothing, _) -> alreadyrunning - (_, Nothing) -> alreadyrunning + (Nothing, _) -> alreadyRunning + (_, Nothing) -> alreadyRunning _ -> do _ <- fdWrite fd' =<< show <$> getProcessID renameFile newfile file closeFd fd where newfile = file ++ ".new" - alreadyrunning = error "Daemon is already running." + +alreadyRunning :: IO () +alreadyRunning = error "Daemon is already running." {- Checks if the daemon is running, by checking that the pid file - is locked by the same process that is listed in the pid file. |