#4449: GHC 7 can't do IO when demonized
----------------------------+-----------------------------------------------
Reporter: kazu-yamamoto | Owner: tibbe
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.1
Resolution: | Keywords: forkProcess
Testcase: | Blockedby:
Difficulty: | Os: MacOS X
Blocking: | Architecture: x86
Failure: None/Unknown |
----------------------------+-----------------------------------------------
Changes (by igloo):
* owner: => tibbe
Comment:
On OS X, this program:
{{{
import Control.Concurrent
import Network
import System.IO
import Prelude hiding (catch)
import System
import System.Posix
main :: IO ()
main = daemonize $ do
writeFile "X1" "Here"
s <- listenOn (Service "7000")
writeFile "X2" "Here"
loop s
writeFile "X3" "Here"
return ()
loop :: Socket -> IO ()
loop s = do
writeFile "X4" "Here"
(hdr,_,_) <- accept s
writeFile "X5" "Here"
_ <- forkIO $ echo hdr
writeFile "X6" "Here"
loop s
echo :: Handle -> IO ()
echo hdr = do
writeFile "X7" "Here"
str <- hGetLine hdr
writeFile "X8" "Here"
hPutStrLn hdr str
writeFile "X9" "Here"
hClose hdr
writeFile "X0" "Here"
return ()
daemonize :: IO () -> IO ()
daemonize program =
do _ <- setFileCreationMask 0
_ <- forkProcess p
exitImmediately ExitSuccess
where
p = do _ <- createSession
_ <- forkProcess p'
exitImmediately ExitSuccess
p' = do -- changeWorkingDirectory "/"
closeFileDescriptors
blockSignal sigHUP
program
closeFileDescriptors :: IO ()
closeFileDescriptors =
do devNull <- openFd "/dev/null" ReadWrite Nothing defaultFileFlags
let redirectTo fd' fd = closeFd fd >> dupTo fd' fd
mapM_ (redirectTo devNull) [stdInput, stdOutput, stdError]
blockSignal :: Signal -> IO ()
blockSignal sig = installHandler sig Ignore Nothing >> pass
pass :: IO ()
pass = return ()
}}}
creates `X4` but not `X5` when I compile it with
{{{
ghc --make q -threaded
}}}
with 7.0.1 RC 2. It works when compiled with 6.12.3. Both have
`network-2.2.3.1`.
Tibbe, you're an OS X person, aren't you? As this seems to involve an
overlap of network and the new IO manager, would you be able to take a
look please?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4449#comment:22>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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