diego souza
I'm having problems with executeFile as it seems to clear the advisory locks using the threaded runtime.
I'm stumped, and unfortunately can't duplicate it here (no surprise as I have a different platform and GHC version.) But in case it helps ... your fcntl(2) file lock will be lost if your process closes any fd open on that file. So if the threaded runtime for some reason were to dup random fds and then close them, around a fork, that would do it. You might be able to pick that up in an strace (or whatever your platform utility for system call tracing.) But I don't see how executeFile could make any difference, in that scenario. Donn
Consider the following snippet (a simplification of what I'm doing):
import System.IO import Control.Monad import System.Posix.IO import Control.Concurrent import System.Posix.Files import System.Posix.Process
main = do let lock = (WriteLock, AbsoluteSeek, 0, 0) fd <- openFd "/tmp/foobar" ReadWrite (Just stdFileMode) defaultFileFlags {trunc=True} pid <- forkProcess $ do setLock fd lock >> putStrLn "child: ok" executeFile "/usr/bin/sleep" False ["5"] Nothing threadDelay $ 1 * 1000 * 1000 setLock fd lock >> putStrLn "parent: fail!" void $ getProcessStatus True False pid
Then I consistentlty get these results:
$ ghc -threaded --make test.hs; ./test child: ok parent: fail!
$ ghc -rtsopts --make test.hs; ./test child: ok test: setLock: resource exhausted (Resource temporarily unavailable)
Any pointers? At first I though it might be an issue with the unix package but that doesn't seem to be the case.
$ ghc-pkg list | grep unix unix-2.6.0.1
$ ./test +RTS --info [("GHC RTS", "YES") ,("GHC version", "7.6.3") ,("RTS way", "rts_thr") ,("Build platform", "x86_64-unknown-linux") ,("Build architecture", "x86_64") ,("Build OS", "linux") ,("Build vendor", "unknown") ,("Host platform", "x86_64-unknown-linux") ,("Host architecture", "x86_64") ,("Host OS", "linux") ,("Host vendor", "unknown") ,("Target platform", "x86_64-unknown-linux") ,("Target architecture", "x86_64") ,("Target OS", "linux") ,("Target vendor", "unknown") ,("Word size", "64") ,("Compiler unregisterised", "NO") ,("Tables next to code", "YES") ]
Thanks! ~dsouza _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe