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authorGravatar Joey Hess <joey@kitenet.net>2012-08-01 16:29:38 -0400
committerGravatar Joey Hess <joey@kitenet.net>2012-08-01 16:30:53 -0400
commit8181b38ef6060103953ce464d03e9cfd75c45663 (patch)
tree0ec9cc7219dd80590cff0cdfdac817b72728dc68 /Utility/Daemon.hs
parentecc168aba30a0477381bcd2037c8d301368f3449 (diff)
write pid file even when running in foreground
This prevents multiple runs of the assistant in the foreground, and lets --stop stop foregrounded runs too. The webapp firstrun case also now writes a pid file, once it's made the git repo to put it in.
Diffstat (limited to 'Utility/Daemon.hs')
-rw-r--r--Utility/Daemon.hs16
1 files changed, 8 insertions, 8 deletions
diff --git a/Utility/Daemon.hs b/Utility/Daemon.hs
index 3386ea443..ba2b2c9c3 100644
--- a/Utility/Daemon.hs
+++ b/Utility/Daemon.hs
@@ -27,7 +27,7 @@ daemonize logfd pidfile changedirectory a = do
_ <- forkProcess child2
out
child2 = do
- maybe noop (lockPidFile alreadyrunning) pidfile
+ maybe noop lockPidFile pidfile
when changedirectory $
setCurrentDirectory "/"
nullfd <- openFd "/dev/null" ReadOnly Nothing defaultFileFlags
@@ -39,28 +39,28 @@ daemonize logfd pidfile changedirectory a = do
redir newh h = do
closeFd h
dupTo newh h
- alreadyrunning = error "Daemon is already running."
out = exitImmediately ExitSuccess
{- Locks the pid file, with an exclusive, non-blocking lock.
- - Runs an action on failure. On success, writes the pid to the file,
- - fully atomically. -}
-lockPidFile :: IO () -> FilePath -> IO ()
-lockPidFile onfailure file = do
+ - Writes the pid to the file, fully atomically.
+ - Fails if the pid file is already locked by another process. -}
+lockPidFile :: FilePath -> IO ()
+lockPidFile file = do
fd <- openFd file ReadWrite (Just stdFileMode) defaultFileFlags
locked <- catchMaybeIO $ setLock fd (WriteLock, AbsoluteSeek, 0, 0)
fd' <- openFd newfile ReadWrite (Just stdFileMode) defaultFileFlags
{ trunc = True }
locked' <- catchMaybeIO $ setLock fd' (WriteLock, AbsoluteSeek, 0, 0)
case (locked, locked') of
- (Nothing, _) -> onfailure
- (_, Nothing) -> onfailure
+ (Nothing, _) -> alreadyrunning
+ (_, Nothing) -> alreadyrunning
_ -> do
_ <- fdWrite fd' =<< show <$> getProcessID
renameFile newfile file
closeFd fd
where
newfile = file ++ ".new"
+ 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.