lukko (empty) → 0.1

raw patch · 17 files changed

+2298/−0 lines, 17 filesdep +asyncdep +basedep +bytestring

Dependencies added: async, base, bytestring, filepath, lukko, tasty, tasty-hunit, temporary

Files

• LICENSE +52/−0
• LICENSE.GPLv2 +348/−0
• LICENSE.GPLv3 +678/−0
• cbits/windows.c +30/−0
• lukko.cabal +153/−0
• src-flock/Lukko/FLock.hsc +118/−0
• src-ofd/Lukko/OFD.hsc +174/−0
• src-unix/Lukko/Internal/FD.hsc +63/−0
• src-windows/Lukko/Internal/FD.hsc +86/−0
• src-windows/Lukko/Windows.hsc +159/−0
• src/Lukko.hs +145/−0
• src/Lukko/Internal/FillBytes.hs +21/−0
• src/Lukko/Internal/HandleToFD.hs +32/−0
• src/Lukko/Internal/Types.hs +25/−0
• src/Lukko/NoOp.hs +62/−0
• test/TestProcess.hs +75/−0
• test/Tests.hs +77/−0

@@ -0,0 +1,52 @@+SPDX-License-Identifier: GPL-2.0-or-later AND BSD-3-Clause++Copyright (c) 2019  Oleg Grenrus <oleg.grenrus@iki.fi>++    This library is free software: you may copy, redistribute and/or modify it+    under the terms of the GNU General Public License as published by the+    Free Software Foundation, either version 3 of the License, or (at your+    option) any later version.++    This library is distributed in the hope that it will be useful, but+    WITHOUT ANY WARRANTY; without even the implied warranty of+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU+    General Public License for more details.++    You should have received a copy of the GNU General Public License+    along with this program (see `LICENSE.GPLv3`).  If not, see+    <https://www.gnu.org/licenses/gpl-3.0.html>.++This library incorporates work covered by the following copyright and+permission notice:++    The Glasgow Haskell Compiler License++    Copyright 2004, The University Court of the University of Glasgow.+    All rights reserved.++    Redistribution and use in source and binary forms, with or without+    modification, are permitted provided that the following conditions are met:++    - Redistributions of source code must retain the above copyright notice,+    this list of conditions and the following disclaimer.++    - Redistributions in binary form must reproduce the above copyright notice,+    this list of conditions and the following disclaimer in the documentation+    and/or other materials provided with the distribution.++    - Neither name of the University nor the names of its contributors may be+    used to endorse or promote products derived from this software without+    specific prior written permission.++    THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF+    GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND+    FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE+    UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR+    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER+    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH+    DAMAGE.

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@@ -0,0 +1,30 @@+#include <windows.h>++// from https://github.com/ghc/ghc/blob/4b431f334018eaef2cf36de3316025c68c922915/utils/fs/fs.c+HANDLE *fdOpen(LPCWSTR filename) {+    // Construct access mode.+    // https://docs.microsoft.com/en-us/windows/win32/fileio/file-access-rights-constants+    DWORD dwDesiredAccess = GENERIC_WRITE | GENERIC_READ;++    // Construct shared mode.+    // https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants+    DWORD dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;++    // Create file disposition.+    // https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew+    DWORD dwCreationDisposition = OPEN_ALWAYS;++    // Set file access attributes.+    DWORD dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;++    SECURITY_ATTRIBUTES securityAttributes;+    ZeroMemory (&securityAttributes, sizeof(SECURITY_ATTRIBUTES));+    securityAttributes.bInheritHandle       = TRUE; // not sure what should be here+    securityAttributes.lpSecurityDescriptor = NULL;+    securityAttributes.nLength              = sizeof(SECURITY_ATTRIBUTES);++    HANDLE res = CreateFileW(filename, dwDesiredAccess, dwShareMode, &securityAttributes,+        dwCreationDisposition, dwFlagsAndAttributes, NULL);++    return res;+}

@@ -0,0 +1,153 @@+cabal-version: 2.2+name:          lukko+version:       0.1+synopsis:      File locking+category:      System, Concurrency+description:+  This package provides access to platform dependent file locking APIs:+  .+  * Open file descriptor locking on Linux ("Lukko.OFD")+  * @flock@ locking on unix platforms ("Lukko.FLock")+  * Windows locking @LockFileEx@ ("Lukko.Windows")+  * No-op locking, which throws exceptions ("Lukko.NoOp")+  * "Lukko" module exports the best option for the target platform with uniform API.+  .+  There are alternative file locking packages:+  .+  * "GHC.IO.Handle.Lock" in @base >= 4.10@ is good enough for most use cases.+  However, uses only 'Handle's so these locks cannot be used for intra-process locking.+  (You should use e.g. 'MVar' in addition).+  .+  * <https://hackage.haskell.org/package/filelock filelock> doesn't support OFD locking.+  .+  /Lukko/ means lock in Finnish.+  .+  Submodules "Lukko.OFD", "Lukko.Windows" etc are available based on following conditions.+  .+  @+  if os(windows)+  \  cpp-options: -DHAS_WINDOWS_LOCK+  .+  elif (os(linux) && flag(ofd-locking))+  \  cpp-options: -DHAS_OFD_LOCKING+  \  cpp-options: -DHAS_FLOCK+  .+  elif !(os(solaris) || os(aix))+  \  cpp-options: -DHAS_FLOCK+  @+  .+  "Lukko.FLock" is available on not (Windows or Solaris or AIX).+  "Lukko.NoOp" is always available.++maintainer:    Oleg Grenrus <oleg.grenrus@iki.fi>+license:       GPL-2.0-or-later AND BSD-3-Clause+license-files: LICENSE LICENSE.GPLv2 LICENSE.GPLv3+build-type:    Simple+tested-with:+  GHC ==7.6.3+   || ==7.8.4+   || ==7.10.3+   || ==8.0.2+   || ==8.2.2+   || ==8.4.4+   || ==8.6.5+   || ==8.8.1++source-repository head+  type:     git+  location: https://github.com/phadej/lukko/++flag ofd-locking+  default:     True+  manual:      True+  description:+    Enable open file descriptor locking. Available on Linux (kernel 3.15, released Jun 8, 2014).++library+  default-language:   Haskell2010+  hs-source-dirs:     src+  build-depends:      base >=4.5 && <4.14+  build-tool-depends: hsc2hs:hsc2hs >=0.67 && <0.69++  -- Main library module+  exposed-modules:+    Lukko+    Lukko.NoOp++  if os(windows)+    hs-source-dirs:  src-windows+    cpp-options:     -DUSE_WINDOWS_LOCK+    exposed-modules: Lukko.Windows+    c-sources:       cbits/windows.c++  elif (os(linux) && flag(ofd-locking))+    hs-source-dirs:  src-ofd+    hs-source-dirs:  src-flock+    hs-source-dirs:  src-unix+    cpp-options:     -DUSE_OFD_LOCKING+    exposed-modules: Lukko.OFD++  elif !(os(solaris) || os(aix))+    hs-source-dirs: src-flock+    hs-source-dirs: src-unix+    cpp-options:    -DUSE_FLOCK++  else+    hs-source-dirs: src-unix+    cpp-options:    -DUSE_NOOP++  -- Cabal check is silly+  if (!os(windows) && !(os(solaris) || os(aix)))+    exposed-modules: Lukko.FLock++  other-modules:+    Lukko.Internal.FD+    Lukko.Internal.FillBytes+    Lukko.Internal.HandleToFD+    Lukko.Internal.Types++test-suite test-thread+  default-language: Haskell2010+  type:             exitcode-stdio-1.0+  hs-source-dirs:   test+  main-is:          Tests.hs+  ghc-options:      -threaded+  build-depends:+    , async        ^>=2.2.2+    , base+    , filepath     ^>=1.3.0.0 || ^>=1.4.0.0+    , lukko+    , tasty        ^>=1.2.3+    , tasty-hunit  ^>=0.10.0.2+    , temporary    ^>=1.3++  if os(windows)+    cpp-options: -DHAS_WINDOWS_LOCK++  elif (os(linux) && flag(ofd-locking))+    cpp-options: -DHAS_OFD_LOCKING+    cpp-options: -DHAS_FLOCK++  elif !(os(solaris) || os(aix))+    cpp-options: -DHAS_FLOCK++test-suite test-process+  default-language: Haskell2010+  type:             exitcode-stdio-1.0+  hs-source-dirs:   test+  main-is:          TestProcess.hs+  ghc-options:      -threaded+  build-depends:+    , base+    , bytestring  >=0.9.2.1 && <0.11+    , lukko++  if os(windows)+    cpp-options: -DHAS_WINDOWS_LOCK++  elif (os(linux) && flag(ofd-locking))+    cpp-options: -DHAS_OFD_LOCKING+    cpp-options: -DHAS_FLOCK++  elif !(os(solaris) || os(aix))+    cpp-options: -DHAS_FLOCK

@@ -0,0 +1,118 @@+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE CPP #-}+{-# LANGUAGE Trustworthy #-}+-- | File locking via POSIX @flock@.+module Lukko.FLock (+    -- * Types+    FileLockingNotSupported(..),+    fileLockingSupported,+    FileLockingMethod (..),+    fileLockingMethod,+    LockMode(..),+    -- * File descriptors+    FD,+    fdOpen,+    fdClose,+    fdLock,+    fdTryLock,+    fdUnlock,+    -- * Handles+    hLock,+    hTryLock,+    hUnlock,+    ) where++#include <sys/file.h>++import Control.Monad (void)+import System.IO (Handle)++import Data.Bits+import Data.Function+import Foreign.C.Error+import Foreign.C.Types+import GHC.Base+import GHC.IO.Exception++import Lukko.Internal.FD+import Lukko.Internal.Types++-------------------------------------------------------------------------------+-- Support constants+-------------------------------------------------------------------------------++-- | A constants specifying whether file locking is supported.+fileLockingSupported :: Bool+fileLockingSupported = True++-- | A constant specifying this method+fileLockingMethod :: FileLockingMethod+fileLockingMethod = MethodFLock++-------------------------------------------------------------------------------+-- FD+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+fdLock :: FD -> LockMode -> IO ()+fdLock fd mode = void (lockImpl Nothing fd "fdLock" mode True)++-- | Try to lock using OFD locks.+fdTryLock :: FD -> LockMode -> IO Bool+fdTryLock fd mode = lockImpl Nothing fd "fdTryLock" mode False++-- | Unlock using OFD locks.+fdUnlock :: FD -> IO ()+fdUnlock = unlockImpl++-------------------------------------------------------------------------------+-- Handle+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+hLock :: Handle -> LockMode -> IO ()+hLock h mode = do+    fd <- handleToFd h+    void (lockImpl (Just h) fd "hLock" mode True)++-- | Try to lock using OFD locks.+hTryLock :: Handle -> LockMode -> IO Bool+hTryLock h mode = do+    fd <- handleToFd h+    lockImpl (Just h) fd "hTryLock" mode False++-- | Unlock using OFD locks.+hUnlock :: Handle -> IO ()+hUnlock h = do+    fd <- handleToFd h+    unlockImpl fd++-------------------------------------------------------------------------------+-- Compat stuff+-------------------------------------------------------------------------------++-------------------------------------------------------------------------------+-- implementation+-------------------------------------------------------------------------------++lockImpl :: Maybe Handle -> FD -> String -> LockMode -> Bool -> IO Bool+lockImpl mh (FD fd)  ctx mode block = do+  let flags = cmode .|. (if block then 0 else #{const LOCK_NB})+  fix $ \retry -> c_flock fd flags >>= \res -> case res of+    0 -> return True+    _ -> getErrno >>= \errno -> case () of+      _ | not block+        , errno == eAGAIN || errno == eACCES -> return False+        | errno == eINTR -> retry+        | otherwise -> ioException $ errnoToIOError ctx errno mh Nothing+  where+    cmode = case mode of+      SharedLock    -> #{const LOCK_SH}+      ExclusiveLock -> #{const LOCK_EX}++unlockImpl :: FD -> IO ()+unlockImpl (FD fd) = do+  throwErrnoIfMinus1_ "flock" $ c_flock fd #{const LOCK_UN}++foreign import ccall interruptible "flock"+  c_flock :: CInt -> CInt -> IO CInt

@@ -0,0 +1,174 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE Trustworthy #-}+-- | Linux open file descriptor locking.+-- +-- <https://www.gnu.org/software/libc/manual/html_node/Open-File-Description-Locks.html>+--+-- We prefer this over BSD locking (e.g. flock) since the latter appears to+-- break in some NFS configurations. Note that we intentionally do not try to+-- use ordinary POSIX file locking due to its peculiar semantics under+-- multi-threaded environments.+--+module Lukko.OFD (+    -- * Types+    FileLockingNotSupported(..),+    fileLockingSupported,+    FileLockingMethod (..),+    fileLockingMethod,+    LockMode(..),+    -- * File descriptors+    FD,+    fdOpen,+    fdClose,+    fdLock,+    fdTryLock,+    fdUnlock,+    -- * Handles+    hLock,+    hTryLock,+    hUnlock,+    ) where++#define _GNU_SOURCE+#include <unistd.h>+#include <fcntl.h>++import Control.Monad (void)+import System.IO (Handle)++import Data.Function+import Foreign.C.Error+import Foreign.C.Types+import Foreign.Marshal.Utils+import Foreign.Storable+import GHC.IO.Exception+import GHC.Ptr+import System.Posix.Types (COff, CPid)++import Lukko.Internal.FD+import Lukko.Internal.FillBytes+import Lukko.Internal.Types++-------------------------------------------------------------------------------+-- Support constants+-------------------------------------------------------------------------------++-- | A constants specifying whether file locking is supported.+fileLockingSupported :: Bool+fileLockingSupported = True++-- | A constant specifying this method+fileLockingMethod :: FileLockingMethod+fileLockingMethod = MethodOFD++-------------------------------------------------------------------------------+-- FD+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+fdLock :: FD -> LockMode -> IO ()+fdLock fd mode = void (lockImpl Nothing fd "fdLock" mode True)++-- | Try to lock using OFD locks.+fdTryLock :: FD -> LockMode -> IO Bool+fdTryLock fd mode = lockImpl Nothing fd "fdTryLock" mode False++-- | Unlock using OFD locks.+fdUnlock :: FD -> IO ()+fdUnlock = unlockImpl++-------------------------------------------------------------------------------+-- Handle+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+hLock :: Handle -> LockMode -> IO ()+hLock h mode = do+    fd <- handleToFd h+    void (lockImpl (Just h) fd "hLock" mode True)++-- | Try to lock using OFD locks.+hTryLock :: Handle -> LockMode -> IO Bool+hTryLock h mode = do+    fd <- handleToFd h+    lockImpl (Just h) fd "hTryLock" mode False++-- | Unlock using OFD locks.+hUnlock :: Handle -> IO ()+hUnlock h = do+    fd <- handleToFd h+    unlockImpl fd++-------------------------------------------------------------------------------+-- Compat+-------------------------------------------------------------------------------++-- there is no alignment in old hsc2hs+#let alignmentcompat t = "%lu", (unsigned long)offsetof(struct {char x__; t (y__); }, y__)++-------------------------------------------------------------------------------+-- implementation+-------------------------------------------------------------------------------++foreign import ccall interruptible "fcntl"+  c_fcntl :: CInt -> CInt -> Ptr FLock -> IO CInt++data FLock  = FLock { l_type   :: CShort+                    , l_whence :: CShort+                    , l_start  :: COff+                    , l_len    :: COff+                    , l_pid    :: CPid+                    }++instance Storable FLock where+    sizeOf _ = #{size struct flock}+    alignment _ = #{alignmentcompat struct flock}+    poke ptr x = do+        fillBytes ptr 0 (sizeOf x)+        #{poke struct flock, l_type}   ptr (l_type x)+        #{poke struct flock, l_whence} ptr (l_whence x)+        #{poke struct flock, l_start}  ptr (l_start x)+        #{poke struct flock, l_len}    ptr (l_len x)+        #{poke struct flock, l_pid}    ptr (l_pid x)+    peek ptr = do+        x1 <- #{peek struct flock, l_type}   ptr+        x2 <- #{peek struct flock, l_whence} ptr+        x3 <- #{peek struct flock, l_start}  ptr+        x4 <- #{peek struct flock, l_len}    ptr+        x5 <- #{peek struct flock, l_pid}    ptr+        return (FLock x1 x2 x3 x4 x5)++lockImpl :: Maybe Handle -> FD -> String -> LockMode -> Bool -> IO Bool+lockImpl mh (FD fd) ctx mode block = do+  with flock $ \flock_ptr -> fix $ \retry -> do+      ret <- c_fcntl fd mode' flock_ptr+      case ret of+        0 -> return True+        _ -> getErrno >>= \errno -> case () of+          _ | not block && errno == eWOULDBLOCK -> return False+            | errno == eINTR -> retry+            | otherwise -> ioException $ errnoToIOError ctx errno mh Nothing+  where+    flock = FLock { l_type = case mode of+                               SharedLock -> #{const F_RDLCK}+                               ExclusiveLock -> #{const F_WRLCK}+                  , l_whence = #{const SEEK_SET}+                  , l_start = 0+                  , l_len = 0+                  , l_pid = 0+                  }+    mode'+      | block     = #{const F_OFD_SETLKW}+      | otherwise = #{const F_OFD_SETLK}++unlockImpl :: FD -> IO ()+unlockImpl (FD fd) = do+  let flock = FLock { l_type = #{const F_UNLCK}+                    , l_whence = #{const SEEK_SET}+                    , l_start = 0+                    , l_len = 0+                    , l_pid = 0+                    }+  throwErrnoIfMinus1_ "hUnlock"+      $ with flock $ c_fcntl fd #{const F_OFD_SETLK}

@@ -0,0 +1,63 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE Trustworthy #-}+module Lukko.Internal.FD (+    FD (..),+    fdOpen,+    fdClose,+    handleToFd,+    ) where++#include <unistd.h>+#include <fcntl.h>++import Data.Bits          ((.|.))+import Foreign.C.Error    (throwErrnoIfMinus1Retry)+import Foreign.C.Types+import Foreign.C.String   (CString, withCString)+import System.IO          (Handle)+import System.Posix.Types (CMode (..))++import qualified GHC.IO.FD        as GHC (FD (..))++import Lukko.Internal.HandleToFD (ghcHandleToFd)++-- | Opaque /file descriptor/+--+-- This is a wrapper over 'CInt'+newtype FD = FD CInt++foreign import ccall interruptible "open"+   c_open :: CString -> CInt -> CMode -> IO CInt++foreign import ccall interruptible "close"+   c_close :: CInt -> IO CInt++-- | Open file to be used for locking.+--+-- @+-- open(path, O_RDWR | O_CREAT);+-- @+fdOpen :: FilePath -> IO FD+fdOpen fp = withCString fp $ \cfp -> do+    fd <- throwErrnoIfMinus1Retry "open" $ c_open cfp flags mode+    return (FD fd)+  where+    flags = #{const O_RDWR} .|. #{const O_CREAT}+    mode  = CMode 0o666++-- | Close lock file.+--+-- @+-- close(fd);+-- @+fdClose :: FD -> IO ()+fdClose (FD fd) =  do+    ret <- throwErrnoIfMinus1Retry "close" $ c_close fd+    return ()++-- | Convert GHC 'Handle' to lukko 'FD'.+handleToFd :: Handle -> IO FD+handleToFd h = do+    GHC.FD {GHC.fdFD = fd} <- ghcHandleToFd h+    return (FD fd)

@@ -0,0 +1,86 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE Trustworthy #-}+module Lukko.Internal.FD (+    FD (..),+    fdOpen,+    fdClose,+    handleToFd,+    ) where++import System.IO (Handle)+import GHC.Windows (iNVALID_HANDLE_VALUE, HANDLE, LPWSTR, BOOL, getLastError, failWith)+import Foreign.C.Types (CInt (..))+import Foreign.C.Error (throwErrnoIf)+import Foreign.C.String (withCWString)+import Foreign.Ptr (Ptr)++import qualified GHC.IO.FD        as GHC (FD (..))++import Lukko.Internal.HandleToFD (ghcHandleToFd)++-- | Opaque /file descriptor/+--+-- This is a wrapper over 'HANDLE'+newtype FD = FD HANDLE++-- | Open file to be used for locking+--+-- @+-- createFileW(path,+--   GENERIC_WRITE | GENERIC_READ,+--   FILE_SHARE_READ | FILE_SHARE_WRITE,+--   securityAttributes, // bInheritHandle = TRUE+--   OPEN_ALWAYS,+--   FILE_ATTRIBUTE_NORMAL,+--   NULL);+-- @+fdOpen :: FilePath -> IO FD+fdOpen fp = withCWString fp $ \cfp -> do+    fw <- c_fdOpen cfp+    if fw /= iNVALID_HANDLE_VALUE+    then return (FD fw)+    else getLastError >>= failWith "fdOpen"++-- | Close lock file.+--+-- @+-- CloseHandle(h);+-- @+fdClose :: FD -> IO ()+fdClose (FD fw) = do+    r <- c_CloseHandle fw+    if r+    then return ()+    else getLastError >>= failWith "fdClose"++-- | Convert GHC 'Handle' to lukko 'FD'.+handleToFd :: Handle -> IO FD+handleToFd h = do+    GHC.FD {GHC.fdFD = fd} <- ghcHandleToFd h+    wh <- throwErrnoIf (== iNVALID_HANDLE_VALUE) "handleToFd" $ c_get_osfhandle fd+    return (FD wh)++-- https://msdn.microsoft.com/en-us/library/aa297958.aspx+foreign import ccall unsafe "_get_osfhandle"+  c_get_osfhandle :: CInt -> IO HANDLE++-- Opening file is complicated+foreign import ccall interruptible "fdOpen"+  c_fdOpen :: LPWSTR -> IO HANDLE++#if defined(i386_HOST_ARCH)++-- https://docs.microsoft.com/en-gb/windows/win32/api/handleapi/nf-handleapi-closehandle+foreign import stdcall interruptible "CloseHandle"+  c_CloseHandle :: HANDLE -> IO BOOL++#elif defined(x86_64_HOST_ARCH)++-- https://docs.microsoft.com/en-gb/windows/win32/api/handleapi/nf-handleapi-closehandle+foreign import ccall interruptible "CloseHandle"+  c_CloseHandle :: HANDLE -> IO BOOL++#else+#error Unknown mingw32 arch+#endif

@@ -0,0 +1,159 @@+{-# LANGUAGE CPP #-}+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE Trustworthy #-}+-- | File locking for Windows.+module Lukko.Windows (+    -- * Types+    FileLockingNotSupported(..),+    fileLockingSupported,+    FileLockingMethod (..),+    fileLockingMethod,+    LockMode(..),+    -- * File descriptors+    FD,+    fdOpen,+    fdClose,+    fdLock,+    fdTryLock,+    fdUnlock,+    -- * Handles+    hLock,+    hTryLock,+    hUnlock,+    ) where++#include <windows.h>++import Control.Monad (void)+import System.IO     (Handle)++import Data.Bits+import Data.Function+import Foreign.C.Error+import Foreign.C.Types+import Foreign.Marshal.Alloc+import Foreign.Marshal.Utils+import Foreign.Ptr (Ptr)+import GHC.Windows++import Lukko.Internal.FD+import Lukko.Internal.FillBytes+import Lukko.Internal.Types++#if defined(i386_HOST_ARCH)+#define WINDOWS_CCONV stdcall+#elif defined(x86_64_HOST_ARCH)+#define WINDOWS_CCONV ccall+#else+#error Unknown mingw32 arch+#endif++-------------------------------------------------------------------------------+-- Support constants+-------------------------------------------------------------------------------++-- | A constants specifying whether file locking is supported.+fileLockingSupported :: Bool+fileLockingSupported = True++-- | A constant specifying this method+fileLockingMethod :: FileLockingMethod+fileLockingMethod = MethodWindows++-------------------------------------------------------------------------------+-- FD+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+fdLock :: FD -> LockMode -> IO ()+fdLock fd mode = void (lockImpl Nothing fd "fdLock" mode True)++-- | Try to lock using OFD locks.+fdTryLock :: FD -> LockMode -> IO Bool+fdTryLock fd mode = lockImpl Nothing fd "fdTryLock" mode False++-- | Unlock using OFD locks.+fdUnlock :: FD -> IO ()+fdUnlock = unlockImpl++-------------------------------------------------------------------------------+-- Handle+-------------------------------------------------------------------------------++-- | Lock using OFD locks.+hLock :: Handle -> LockMode -> IO ()+hLock h mode = do+    fd <- handleToFd h+    void (lockImpl (Just h) fd "hLock" mode True)++-- | Try to lock using OFD locks.+hTryLock :: Handle -> LockMode -> IO Bool+hTryLock h mode = do+    fd <- handleToFd h+    lockImpl (Just h) fd "hTryLock" mode False++-- | Unlock using OFD locks.+hUnlock :: Handle -> IO ()+hUnlock h = do+    fd <- handleToFd h+    unlockImpl fd++-------------------------------------------------------------------------------+-- implementation+-------------------------------------------------------------------------------++lockImpl :: Maybe Handle -> FD -> String -> LockMode -> Bool -> IO Bool+lockImpl _ (FD wh) ctx mode block = do+  allocaBytes sizeof_OVERLAPPED $ \ovrlpd -> do+    fillBytes ovrlpd 0 sizeof_OVERLAPPED+    let flags = cmode .|. (if block then 0 else #{const LOCKFILE_FAIL_IMMEDIATELY})+    -- We want to lock the whole file without looking up its size to be+    -- consistent with what flock does. According to documentation of LockFileEx+    -- "locking a region that goes beyond the current end-of-file position is+    -- not an error", hence we pass maximum value as the number of bytes to+    -- lock.+    fix $ \retry -> c_LockFileEx wh flags 0 0xffffffff 0xffffffff ovrlpd >>= \res -> case res of+      True  -> return True+      False -> getLastError >>= \err -> case () of+        _ | not block && err == #{const ERROR_LOCK_VIOLATION} -> return False+          | err == #{const ERROR_OPERATION_ABORTED} -> retry+          | otherwise -> failWith ctx err+  where+    sizeof_OVERLAPPED = #{size OVERLAPPED}++    cmode = case mode of+      SharedLock    -> 0+      ExclusiveLock -> #{const LOCKFILE_EXCLUSIVE_LOCK}++unlockImpl :: FD -> IO ()+unlockImpl (FD wh) = do+  allocaBytes sizeof_OVERLAPPED $ \ovrlpd -> do+    fillBytes ovrlpd 0 sizeof_OVERLAPPED+    c_UnlockFileEx wh 0 0xffffffff 0xffffffff ovrlpd >>= \res -> case res of+      True  -> return ()+      False -> getLastError >>= failWith "fdUnlock"+  where+    sizeof_OVERLAPPED = #{size OVERLAPPED}+#if defined(i386_HOST_ARCH)++-- https://docs.microsoft.com/en-gb/windows/win32/api/fileapi/nf-fileapi-lockfileex+foreign import stdcall interruptible "LockFileEx"+  c_LockFileEx :: HANDLE -> DWORD -> DWORD -> DWORD -> DWORD -> Ptr () -> IO BOOL++-- https://docs.microsoft.com/en-gb/windows/win32/api/fileapi/nf-fileapi-unlockfileex+foreign import stdcall interruptible "UnlockFileEx"+  c_UnlockFileEx :: HANDLE -> DWORD -> DWORD -> DWORD -> Ptr () -> IO BOOL++#elif defined(x86_64_HOST_ARCH)++-- https://docs.microsoft.com/en-gb/windows/win32/api/fileapi/nf-fileapi-lockfileex+foreign import ccall interruptible "LockFileEx"+  c_LockFileEx :: HANDLE -> DWORD -> DWORD -> DWORD -> DWORD -> Ptr () -> IO BOOL++-- https://docs.microsoft.com/en-gb/windows/win32/api/fileapi/nf-fileapi-unlockfileex+foreign import ccall interruptible "UnlockFileEx"+  c_UnlockFileEx :: HANDLE -> DWORD -> DWORD -> DWORD -> Ptr () -> IO BOOL++#else+#error Unknown mingw32 arch+#endif

@@ -0,0 +1,145 @@+{-# LANGUAGE CPP         #-}+{-# LANGUAGE Trustworthy #-}+-- | Open 'Handle' based locking+module Lukko (+    FileLockingNotSupported(..),+    Impl.fileLockingSupported,+    FileLockingMethod (..),+    Impl.fileLockingMethod,+    LockMode(..),+    -- * File descriptors+    FD,+    fdOpen,+    fdClose,+    fdLock,+    fdTryLock,+    fdUnlock,+    -- * Handles+    handleToFd,+    hLock,+    hTryLock,+    hUnlock,+    ) where++{- Parts of these software is derived from GHC sources+   distributed under BSD-3-Clause license:++The Glasgow Haskell Compiler License++Copyright 2004, The University Court of the University of Glasgow.+All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++- Redistributions of source code must retain the above copyright notice,+this list of conditions and the following disclaimer.++- Redistributions in binary form must reproduce the above copyright notice,+this list of conditions and the following disclaimer in the documentation+and/or other materials provided with the distribution.++- Neither name of the University nor the names of its contributors may be+used to endorse or promote products derived from this software without+specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY COURT OF THE UNIVERSITY OF+GLASGOW AND THE CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE+UNIVERSITY COURT OF THE UNIVERSITY OF GLASGOW OR THE CONTRIBUTORS BE LIABLE+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH+DAMAGE.++-}++import Control.Monad (void)+import System.IO     (Handle)++import Lukko.Internal.Types++import qualified Lukko.Internal.FD as Impl++#if defined(USE_OFD_LOCKING)+import qualified Lukko.OFD as Impl+#elif defined(USE_FLOCK)+import qualified Lukko.FLock as Impl+#elif defined(USE_WINDOWS_LOCK)+import qualified Lukko.Windows as Impl+#else+import qualified Lukko.NoOp as Impl+#endif++-------------------------------------------------------------------------------+-- Handles+-------------------------------------------------------------------------------++-- | If a 'Handle' references a file descriptor, attempt to lock contents of the+-- underlying file in appropriate mode. If the file is already locked in+-- incompatible mode, this function blocks until the lock is established. The+-- lock is automatically released upon closing a 'Handle'.+--+-- Things to be aware of:+--+-- 1) This function may block inside a C call. If it does, in order to be able+-- to interrupt it with asynchronous exceptions and/or for other threads to+-- continue working, you MUST use threaded version of the runtime system.+--+-- 2) The implementation uses 'LockFileEx' on Windows,+-- /open file descriptor/ locks on Linux, and 'flock' otherwise,+-- hence all of their caveats also apply here.+--+-- 3) On non-Windows plaftorms that don't support 'flock' (e.g. Solaris) this+-- function throws 'FileLockingNotImplemented'. We deliberately choose to not+-- provide @fcntl@ based locking instead because of its broken semantics.+--+hLock :: Handle -> LockMode -> IO ()+hLock = Impl.hLock++-- | Non-blocking version of 'hLock'.+hTryLock :: Handle -> LockMode -> IO Bool+hTryLock = Impl.hTryLock++-- | Release a lock taken with 'hLock' or 'hTryLock'.+hUnlock :: Handle -> IO ()+hUnlock = Impl.hUnlock++-------------------------------------------------------------------------------+-- File descriptors+-------------------------------------------------------------------------------++-- | Opaque /file descriptor/+--+-- An @int@ / 'CInt' on unix systems,+-- and 'HANDLE' on windows.+type FD = Impl.FD++-- | Open file to be used for locking.+fdOpen :: FilePath -> IO FD+fdOpen = Impl.fdOpen++-- | Close lock file.+fdClose :: FD -> IO ()+fdClose = Impl.fdClose++-- | Convert GHC 'Handle' to lukko 'FD'.+handleToFd :: Handle -> IO FD+handleToFd = Impl.handleToFd++-- | Like 'hLock', but work on "raw" file descriptor,+-- as handled by 'fdOpen' and 'fdClose'.+fdLock :: Impl.FD -> LockMode -> IO ()+fdLock = Impl.fdLock++-- | Non-blocking version of 'fdLock'.+fdTryLock :: Impl.FD -> LockMode -> IO Bool+fdTryLock = Impl.fdTryLock++-- | Release a lock taken with 'fdLock' or 'fdTryLock'.+fdUnlock :: Impl.FD -> IO ()+fdUnlock = Impl.fdUnlock

@@ -0,0 +1,21 @@+{-# LANGUAGE CPP              #-}+{-# LANGUAGE InterruptibleFFI #-}+{-# LANGUAGE Trustworthy      #-}+module Lukko.Internal.FillBytes (fillBytes) where++#if MIN_VERSION_base(4,8,0)+import Foreign.Marshal.Utils (fillBytes)+#else+import Data.Word       (Word8)+import Foreign.C.Types (CInt (..), CSize (..))+import Foreign.Ptr     (Ptr (..))+#endif++#if !MIN_VERSION_base(4,8,0)+fillBytes :: Ptr a -> Word8 -> Int -> IO ()+fillBytes dest char size = do+    _ <- memset dest (fromIntegral char) (fromIntegral size)+    return ()++foreign import ccall unsafe "string.h" memset  :: Ptr a -> CInt  -> CSize -> IO (Ptr a)+#endif

@@ -0,0 +1,32 @@+{-# LANGUAGE CPP         #-}+{-# LANGUAGE Trustworthy #-}+module Lukko.Internal.HandleToFD (ghcHandleToFd) where++import qualified GHC.IO.FD as GHC (FD (..))+import           System.IO (Handle)++#if MIN_VERSION_base(4,10,0)+import qualified GHC.IO.Handle.FD as GHC (handleToFd)+#else+import Control.Concurrent.MVar (readMVar)+import Data.Typeable           (cast)+import GHC.IO.Exception+import GHC.IO.Handle.Internals+import GHC.IO.Handle.Types+#endif++ghcHandleToFd :: Handle -> IO GHC.FD+#if MIN_VERSION_base(4,10,0)+ghcHandleToFd = GHC.handleToFd+#else+ghcHandleToFd h = case h of+    FileHandle _ mv -> do+      Handle__{haDevice = dev} <- readMVar mv+      case cast dev of+          Just fd -> return fd+          Nothing -> throwErr "not a file descriptor"+    DuplexHandle{} -> throwErr "not a file handle"+  where+    throwErr msg = ioException $ IOError (Just h)+      InappropriateType "handleToFd" msg Nothing Nothing+#endif

@@ -0,0 +1,25 @@+{-# LANGUAGE DeriveDataTypeable #-}+{-# LANGUAGE Safe #-}+module Lukko.Internal.Types where++import Control.Exception (Exception)+import Data.Typeable (Typeable)++-- | Exception thrown by 'hLock' on non-Windows platforms that don't support+-- @flock@.+data FileLockingNotSupported = FileLockingNotSupported+  deriving (Typeable, Show)++instance Exception FileLockingNotSupported++-- | Indicates a mode in which a file should be locked.+data LockMode = SharedLock | ExclusiveLock+  deriving (Typeable)++-- | Potentially availble lock methods.+data FileLockingMethod+    = MethodOFD      -- ^ open file descriptor locking+    | MethodFLock    -- ^ BSD @flock@+    | MethodWindows  -- ^ Windows locking+    | MethodNoOp     -- ^ No-Op (throws 'FileLockingNotSupported')+  deriving (Typeable, Eq, Ord, Enum, Bounded, Show)

@@ -0,0 +1,62 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE Safe #-}+-- | Non-operating locks.+--+-- All functions throw 'FileLockingNotImplemented'.+module Lukko.NoOp (+    -- * Types+    FileLockingNotSupported(..),+    fileLockingSupported,+    FileLockingMethod (..),+    fileLockingMethod,+    LockMode(..),+    -- * File descriptors+    FD,+    fdOpen,+    fdClose,+    fdLock,+    fdTryLock,+    fdUnlock,+    -- * Handles+    hLock,+    hTryLock,+    hUnlock,+    ) where++import Control.Exception (throwIO)+import System.IO         (Handle)++import Lukko.Internal.FD+import Lukko.Internal.Types++-- | A constants specifying whether file locking is supported.+fileLockingSupported :: Bool+fileLockingSupported = False++-- | A constant specifying this method+fileLockingMethod :: FileLockingMethod+fileLockingMethod = MethodNoOp++-- | No-op implementation.+hLock :: Handle -> LockMode -> IO ()+hLock _ _ = throwIO FileLockingNotSupported++-- | No-op implementation+hTryLock :: Handle -> LockMode -> IO Bool+hTryLock _ _ = throwIO FileLockingNotSupported++-- | No-op implementation.+hUnlock :: Handle -> IO ()+hUnlock _ = throwIO FileLockingNotSupported++-- | No-op implementation.+fdLock :: FD -> LockMode -> IO ()+fdLock _ _ = throwIO FileLockingNotSupported++-- | No-op implementation+fdTryLock :: FD -> LockMode -> IO Bool+fdTryLock _ _ = throwIO FileLockingNotSupported++-- | No-op implementation.+fdUnlock :: FD -> IO ()+fdUnlock _ = throwIO FileLockingNotSupported

@@ -0,0 +1,75 @@+{-# LANGUAGE CPP               #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RankNTypes        #-}+module Main (main) where++import Control.Concurrent (threadDelay)+import Control.Exception  (bracket)+import System.Environment (getArgs)+import System.IO          (Handle, IOMode (ReadWriteMode), hClose, openFile)++import qualified Data.ByteString as BS+import qualified Data.ByteString.Char8 as BS8++import Lukko++#ifdef HAS_OFD_LOCKING+import qualified Lukko.OFD as OFD+#endif++#ifdef HAS_FLOCK+import qualified Lukko.FLock as FLock+#endif++main :: IO ()+main = withArgs $ \withLock -> do+    putStrLn "starting..."+    withLock $ do+        contents <- BS.readFile "test-actual"+        threadDelay 10000 -- 10 ms+        BS.writeFile "test-actual" $ BS.append contents $ BS8.pack "another line\n"++withArgs+    :: ((forall r. IO r -> IO r) -> IO ())+    -> IO ()+withArgs k = do+    args <- getArgs+    case args of+        ["default"] -> k (genWithLock hLock hUnlock "test-lock")+#ifdef HAS_OFD_LOCKING+        ["ofd"]     -> k (genWithLock OFD.hLock OFD.hUnlock "test-lock")+#endif+#ifdef HAS_FLOCK+        ["flock"]   -> k (genWithLock FLock.hLock FLock.hUnlock "test-lock")+#endif+        ["noop"]    -> k (genWithLock noOpLock noOpUnlock "test-lock")+        _           -> putStrLn "Unknown paramters. Doing nothing."++-------------------------------------------------------------------------------+-- copy pasted+-------------------------------------------------------------------------------++noOpLock :: Handle -> LockMode -> IO ()+noOpLock _ _ = return ()++noOpUnlock :: Handle -> IO ()+noOpUnlock _ = return ()++genWithLock+    :: (Handle -> LockMode -> IO ())+    -> (Handle -> IO ())+    -> FilePath+    -> IO a+    -> IO a+genWithLock implLock implUnlock fp action =+    bracket takeLock releaseLock (const action)+  where+    takeLock = do+        h <- openFile fp ReadWriteMode+        implLock h ExclusiveLock+        return h++    releaseLock :: Handle -> IO ()+    releaseLock h = do+        implUnlock h+        hClose h

@@ -0,0 +1,77 @@+{-# LANGUAGE CPP #-}+module Main (main) where++import Control.Concurrent       (threadDelay)+import Control.Concurrent.Async (forConcurrently_)+import Control.Exception        (bracket)+import Data.IORef+import System.FilePath          ((</>))+import System.IO+       (Handle, IOMode (ReadWriteMode), hClose, openFile)+import System.IO.Temp           (withSystemTempDirectory)+import Test.Tasty               (TestTree, defaultMain, testGroup)+import Test.Tasty.HUnit         (testCase, (@=?))++import Lukko++#ifdef HAS_OFD_LOCKING+import qualified Lukko.OFD as OFD+#endif++#ifdef HAS_FLOCK+import qualified Lukko.FLock as FLock+#endif++main :: IO ()+main = defaultMain $ testGroup "lukko" $+    [ testGroup "Lukko default" $ testSuite fdLock fdUnlock+    | fileLockingSupported+    ]+#ifdef HAS_OFD_LOCKING+    ++ [ testGroup "Lukko.OFD" $ testSuite OFD.fdLock OFD.fdUnlock ]+#endif+#ifdef HAS_FLOCK+    ++ [ testGroup "Lukko.FLock" $ testSuite FLock.fdLock FLock.fdUnlock ]+#endif++testSuite+    :: (FD -> LockMode -> IO ())+    -> (FD -> IO ())+    -> [TestTree]+testSuite implLock implUnlock =+    [ testCase "concurrent threads" $ do+        let n = 10 :: Int+        ref <- newIORef 0++        withSystemTempDirectory "handle-lock-tests" $ \tmpDir -> do+            -- print tmpDir+            forConcurrently_ [1 :: Int .. n] $ \_ ->+                withLock (tmpDir </> "lock") $ do+                    val <- readIORef ref+                    threadDelay 10000 -- 10ms+                    writeIORef ref (succ val)++        val <- readIORef ref+        val @=? n+    ]+  where+    withLock = genWithLock implLock implUnlock++genWithLock+    :: (FD -> LockMode -> IO ())+    -> (FD -> IO ())+    -> FilePath+    -> IO a+    -> IO a+genWithLock implLock implUnlock fp action =+    bracket takeLock releaseLock (const action)+  where+    takeLock = do+        fd <- fdOpen fp+        implLock fd ExclusiveLock+        return fd++    releaseLock :: FD -> IO ()+    releaseLock fd = do+        implUnlock fd+        fdClose fd