git annex watch --stop

This commit is contained in:
Joey Hess 2012-06-11 02:01:20 -04:00
parent 8539a7bde8
commit d0a0a6ae21
3 changed files with 49 additions and 20 deletions

View file

@ -27,7 +27,7 @@ daemonize logfd pidfile changedirectory a = do
_ <- forkProcess child2
out
child2 = do
maybe noop lockPidFile pidfile
maybe noop (lockPidFile True alreadyrunning) pidfile
when changedirectory $
setCurrentDirectory "/"
nullfd <- openFd "/dev/null" ReadOnly Nothing defaultFileFlags
@ -39,12 +39,31 @@ daemonize logfd pidfile changedirectory a = do
redir newh h = do
closeFd h
dupTo newh h
alreadyrunning = error "Daemon is already running."
out = exitImmediately ExitSuccess
lockPidFile :: FilePath -> IO ()
lockPidFile file = void $ do
lockPidFile :: Bool -> IO () -> FilePath -> IO ()
lockPidFile write onfailure file = do
fd <- openFd file ReadWrite (Just stdFileMode) defaultFileFlags
catchIO
(setLock fd (WriteLock, AbsoluteSeek, 0, 0))
(const $ error "Daemon is already running.")
fdWrite fd =<< show <$> getProcessID
when (write) $ void $
fdWrite fd =<< show <$> getProcessID
catchIO (setLock fd (locktype, AbsoluteSeek, 0, 0)) (const onfailure)
where
locktype
| write = WriteLock
| otherwise = ReadLock
{- Stops the daemon.
-
- The pid file is used to get the daemon's pid.
-
- To guard against a stale pid, try to take a nonblocking shared lock
- of the pid file. If this *fails*, the daemon must be running,
- and have the exclusive lock, so the pid file is trustworthy.
-}
stopDaemon :: FilePath -> IO ()
stopDaemon pidfile = lockPidFile False go pidfile
where
go = do
pid <- readish <$> readFile pidfile
maybe noop (signalProcess sigTERM) pid