92 lines
2.9 KiB
Plaintext
92 lines
2.9 KiB
Plaintext
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#if __GLASGOW_HASKELL__ >= 709
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{-# LANGUAGE Safe #-}
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#else
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{-# LANGUAGE Trustworthy #-}
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#endif
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-----------------------------------------------------------------------------
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-- |
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-- Module : System.Posix.SharedMem
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-- Copyright : (c) Daniel Franke 2007
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-- License : BSD-style (see the file libraries/base/LICENSE)
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--
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-- Maintainer : libraries@haskell.org
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-- Stability : experimental
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-- Portability : non-portable (requires POSIX)
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--
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-- POSIX shared memory support.
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--
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-----------------------------------------------------------------------------
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module System.Posix.SharedMem
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(ShmOpenFlags(..), shmOpen, shmUnlink)
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where
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#include "HsUnix.h"
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <fcntl.h>
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import System.Posix.Types
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#if defined(HAVE_SHM_OPEN) || defined(HAVE_SHM_UNLINK)
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import Foreign.C
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#endif
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#ifdef HAVE_SHM_OPEN
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import Data.Bits
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#endif
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data ShmOpenFlags = ShmOpenFlags
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{ shmReadWrite :: Bool,
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-- ^ If true, open the shm object read-write rather than read-only.
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shmCreate :: Bool,
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-- ^ If true, create the shm object if it does not exist.
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shmExclusive :: Bool,
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-- ^ If true, throw an exception if the shm object already exists.
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shmTrunc :: Bool
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-- ^ If true, wipe the contents of the shm object after opening it.
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}
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-- | Open a shared memory object with the given name, flags, and mode.
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shmOpen :: String -> ShmOpenFlags -> FileMode -> IO Fd
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#ifdef HAVE_SHM_OPEN
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shmOpen name flags mode =
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do cflags0 <- return 0
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cflags1 <- return $ cflags0 .|. (if shmReadWrite flags
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then #{const O_RDWR}
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else #{const O_RDONLY})
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cflags2 <- return $ cflags1 .|. (if shmCreate flags then #{const O_CREAT}
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else 0)
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cflags3 <- return $ cflags2 .|. (if shmExclusive flags
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then #{const O_EXCL}
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else 0)
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cflags4 <- return $ cflags3 .|. (if shmTrunc flags then #{const O_TRUNC}
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else 0)
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withCAString name (shmOpen' cflags4)
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where shmOpen' cflags cname =
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do fd <- throwErrnoIfMinus1 "shmOpen" $
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shm_open cname cflags mode
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return $ Fd fd
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#else
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shmOpen = error "System.Posix.SharedMem:shm_open: not available"
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#endif
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-- | Delete the shared memory object with the given name.
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shmUnlink :: String -> IO ()
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#ifdef HAVE_SHM_UNLINK
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shmUnlink name = withCAString name shmUnlink'
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where shmUnlink' cname =
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throwErrnoIfMinus1_ "shmUnlink" $ shm_unlink cname
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#else
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shmUnlink = error "System.Posix.SharedMem:shm_unlink: not available"
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#endif
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#ifdef HAVE_SHM_OPEN
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foreign import ccall unsafe "shm_open"
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shm_open :: CString -> CInt -> CMode -> IO CInt
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#endif
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#ifdef HAVE_SHM_UNLINK
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foreign import ccall unsafe "shm_unlink"
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shm_unlink :: CString -> IO CInt
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#endif
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