summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorGravatar Joey Hess <joey@kitenet.net>2014-08-20 16:45:58 -0400
committerGravatar Joey Hess <joey@kitenet.net>2014-08-20 16:45:58 -0400
commit679d9c0027ac996eea9f41a6f0f39af436801e89 (patch)
treed98ae7ba049e2daa4a99e6bcf55054bde5e5ab4d
parent86f9d7734d0c638d4c966fd87a5d7e97759e125b (diff)
reorganize and refactor lock code
Added a convenience Utility.LockFile that is not a windows/posix portability shim, but still manages to cut down on the boilerplate around locking. This commit was sponsored by Johan Herland.
-rw-r--r--Annex/Content.hs16
-rw-r--r--Annex/LockFile.hs26
-rw-r--r--Annex/Ssh.hs5
-rw-r--r--Command/PreCommit.hs24
-rw-r--r--Remote/Helper/Hooks.hs7
-rw-r--r--Types/LockPool.hs10
-rw-r--r--Utility/LockFile.hs20
-rw-r--r--Utility/LockFile/Posix.hs47
-rw-r--r--Utility/LockFile/Windows.hs (renamed from Utility/WinLock.hs)11
9 files changed, 90 insertions, 76 deletions
diff --git a/Annex/Content.hs b/Annex/Content.hs
index 2a05c2dac..31a4444af 100644
--- a/Annex/Content.hs
+++ b/Annex/Content.hs
@@ -56,10 +56,7 @@ import Annex.Perms
import Annex.Link
import Annex.Content.Direct
import Annex.ReplaceFile
-
-#ifdef mingw32_HOST_OS
-import Utility.WinLock
-#endif
+import Utility.LockFile
{- Checks if a given key's content is currently present. -}
inAnnex :: Key -> Annex Bool
@@ -177,24 +174,21 @@ lockContent key a = do
nukeFile lockfile
#ifndef mingw32_HOST_OS
lock contentfile Nothing = opencontentforlock contentfile >>= dolock
- lock _ (Just lockfile) = openforlock lockfile >>= dolock . Just
+ lock _ (Just lockfile) = createLockFile Nothing lockfile >>= dolock . Just
{- Since content files are stored with the write bit disabled, have
- to fiddle with permissions to open for an exclusive lock. -}
opencontentforlock f = catchMaybeIO $ ifM (doesFileExist f)
( withModifiedFileMode f
(`unionFileModes` ownerWriteMode)
- (openforlock f)
- , openforlock f
+ (createLockFie Nothing f)
+ , createLockFile Nothing f
)
- openforlock f = openFd f ReadWrite Nothing defaultFileFlags
dolock Nothing = return Nothing
dolock (Just fd) = do
v <- tryIO $ setLock fd (WriteLock, AbsoluteSeek, 0, 0)
case v of
Left _ -> alreadylocked
- Right _ -> do
- setFdOption fd CloseOnExec True
- return $ Just fd
+ Right _ -> return $ Just fd
unlock mlockfile mfd = do
maybe noop cleanuplockfile mlockfile
liftIO $ maybe noop closeFd mfd
diff --git a/Annex/LockFile.hs b/Annex/LockFile.hs
index 14aa293ae..75047e005 100644
--- a/Annex/LockFile.hs
+++ b/Annex/LockFile.hs
@@ -19,13 +19,10 @@ import Annex
import Types.LockPool
import qualified Git
import Annex.Perms
+import Utility.LockFile
import qualified Data.Map as M
-#ifdef mingw32_HOST_OS
-import Utility.WinLock
-#endif
-
{- Create a specified lock file, and takes a shared lock, which is retained
- in the pool. -}
lockFileShared :: FilePath -> Annex ()
@@ -35,10 +32,7 @@ lockFileShared file = go =<< fromLockPool file
go Nothing = do
#ifndef mingw32_HOST_OS
mode <- annexFileMode
- lockhandle <- liftIO $ noUmask mode $
- openFd file ReadWrite (Just mode) defaultFileFlags
- liftIO $ setFdOption lockhandle CloseOnExec True
- liftIO $ waitToSetLock lockhandle (ReadLock, AbsoluteSeek, 0, 0)
+ lockhandle <- liftIO $ noUmask mode $ lockShared (Just mode) file
#else
lockhandle <- liftIO $ waitToLock $ lockShared file
#endif
@@ -48,11 +42,7 @@ unlockFile :: FilePath -> Annex ()
unlockFile file = maybe noop go =<< fromLockPool file
where
go lockhandle = do
-#ifndef mingw32_HOST_OS
- liftIO $ closeFd lockhandle
-#else
liftIO $ dropLock lockhandle
-#endif
changeLockPool $ M.delete file
getLockPool :: Annex LockPool
@@ -73,16 +63,10 @@ withExclusiveLock getlockfile a = do
lockfile <- fromRepo getlockfile
createAnnexDirectory $ takeDirectory lockfile
mode <- annexFileMode
- bracketIO (lock lockfile mode) unlock (const a)
+ bracketIO (lock mode lockfile) dropLock (const a)
where
#ifndef mingw32_HOST_OS
- lock lockfile mode = do
- l <- noUmask mode $ createFile lockfile mode
- setFdOption l CloseOnExec True
- waitToSetLock l (WriteLock, AbsoluteSeek, 0, 0)
- return l
- unlock = closeFd
+ lock mode = noUmask mode . lockExclusive (Just mode)
#else
- lock lockfile _mode = waitToLock $ lockExclusive lockfile
- unlock = dropLock
+ lock _mode = waitToLock . lockExclusive
#endif
diff --git a/Annex/Ssh.hs b/Annex/Ssh.hs
index 4b3ee85e5..2b1b809ff 100644
--- a/Annex/Ssh.hs
+++ b/Annex/Ssh.hs
@@ -35,6 +35,7 @@ import Config.Files
import Utility.Env
import Types.CleanupActions
import Annex.Index (addGitEnv)
+import Utility.LockFile
#ifndef mingw32_HOST_OS
import Annex.Perms
#endif
@@ -151,9 +152,7 @@ sshCleanup = mapM_ cleanup =<< enumSocketFiles
let lockfile = socket2lock socketfile
unlockFile lockfile
mode <- annexFileMode
- fd <- liftIO $ noUmask mode $
- openFd lockfile ReadWrite (Just mode) defaultFileFlags
- liftIO $ setFdOption fd CloseOnExec True
+ fd <- liftIO $ noUmask mode $ createLockFile (Just mode) lockfile
v <- liftIO $ tryIO $
setLock fd (WriteLock, AbsoluteSeek, 0, 0)
case v of
diff --git a/Command/PreCommit.hs b/Command/PreCommit.hs
index 61508ba9b..355e2766e 100644
--- a/Command/PreCommit.hs
+++ b/Command/PreCommit.hs
@@ -18,16 +18,12 @@ import Annex.Direct
import Annex.Hook
import Annex.View
import Annex.View.ViewedFile
-import Annex.Perms
+import Annex.LockFile
import Logs.View
import Logs.MetaData
import Types.View
import Types.MetaData
-#ifdef mingw32_HOST_OS
-import Utility.WinLock
-#endif
-
import qualified Data.Set as S
def :: [Command]
@@ -92,20 +88,4 @@ showMetaDataChange = showLongNote . unlines . concatMap showmeta . fromMetaData
{- Takes exclusive lock; blocks until available. -}
lockPreCommitHook :: Annex a -> Annex a
-lockPreCommitHook a = do
- lockfile <- fromRepo gitAnnexPreCommitLock
- createAnnexDirectory $ takeDirectory lockfile
- mode <- annexFileMode
- bracketIO (lock lockfile mode) unlock (const a)
- where
-#ifndef mingw32_HOST_OS
- lock lockfile mode = do
- l <- liftIO $ noUmask mode $ createFile lockfile mode
- setFdOption l CloseOnExec True
- liftIO $ waitToSetLock l (WriteLock, AbsoluteSeek, 0, 0)
- return l
- unlock = closeFd
-#else
- lock lockfile _mode = liftIO $ waitToLock $ lockExclusive lockfile
- unlock = dropLock
-#endif
+lockPreCommitHook = withExclusiveLock gitAnnexPreCommitLock
diff --git a/Remote/Helper/Hooks.hs b/Remote/Helper/Hooks.hs
index cd31a2fd5..96f73cce3 100644
--- a/Remote/Helper/Hooks.hs
+++ b/Remote/Helper/Hooks.hs
@@ -16,10 +16,9 @@ import Types.Remote
import Types.CleanupActions
import qualified Annex
import Annex.LockFile
+import Utility.LockFile
#ifndef mingw32_HOST_OS
import Annex.Perms
-#else
-import Utility.WinLock
#endif
{- Modifies a remote's access functions to first run the
@@ -84,9 +83,7 @@ runHooks r starthook stophook a = do
unlockFile lck
#ifndef mingw32_HOST_OS
mode <- annexFileMode
- fd <- liftIO $ noUmask mode $
- openFd lck ReadWrite (Just mode) defaultFileFlags
- liftIO $ setFdOption fd CloseOnExec True
+ fd <- liftIO $ noUmask mode $ createLockFile (Just mode) lck
v <- liftIO $ tryIO $
setLock fd (WriteLock, AbsoluteSeek, 0, 0)
case v of
diff --git a/Types/LockPool.hs b/Types/LockPool.hs
index dd392f28b..c7d411cdc 100644
--- a/Types/LockPool.hs
+++ b/Types/LockPool.hs
@@ -5,20 +5,12 @@
- Licensed under the GNU GPL version 3 or higher.
-}
-{-# LANGUAGE CPP #-}
-
module Types.LockPool (
LockPool,
LockHandle
) where
import qualified Data.Map as M
-
-#ifndef mingw32_HOST_OS
-import System.Posix.Types (Fd)
-type LockHandle = Fd
-#else
-import Utility.WinLock -- defines LockHandle
-#endif
+import Utility.LockFile
type LockPool = M.Map FilePath LockHandle
diff --git a/Utility/LockFile.hs b/Utility/LockFile.hs
new file mode 100644
index 000000000..4f0d4ba3e
--- /dev/null
+++ b/Utility/LockFile.hs
@@ -0,0 +1,20 @@
+{- Lock files
+ -
+ - Posix and Windows lock files are extremely different.
+ - This module does *not* attempt to be a portability shim, it just exposes
+ - the native locking of the OS.
+ -
+ - Copyright 2014 Joey Hess <joey@kitenet.net>
+ -
+ - License: BSD-2-clause
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module Utility.LockFile (module X) where
+
+#ifndef mingw32_HOST_OS
+import Utility.LockFile.Posix as X
+#else
+import Utility.LockFile.Windows as X
+#endif
diff --git a/Utility/LockFile/Posix.hs b/Utility/LockFile/Posix.hs
new file mode 100644
index 000000000..1538b491a
--- /dev/null
+++ b/Utility/LockFile/Posix.hs
@@ -0,0 +1,47 @@
+{- Posix lock files
+ -
+ - Copyright 2014 Joey Hess <joey@kitenet.net>
+ -
+ - License: BSD-2-clause
+ -}
+
+module Utility.LockFile.Posix (
+ lockShared,
+ lockExclusive,
+ dropLock,
+ createLockFile,
+ LockHandle
+) where
+
+import System.IO
+import System.Posix
+
+type LockFile = FilePath
+
+newtype LockHandle = LockHandle Fd
+
+-- Takes a shared lock, blocking until the lock is available.
+lockShared :: Maybe FileMode -> LockFile -> IO LockHandle
+lockShared = lock ReadLock
+
+-- Takes an exclusive lock, blocking until the lock is available.
+lockExclusive :: Maybe FileMode -> LockFile -> IO LockHandle
+lockExclusive = lock WriteLock
+
+-- The FileMode is used when creating a new lock file.
+lock :: LockRequest -> Maybe FileMode -> LockFile -> IO LockHandle
+lock lockreq mode lockfile = do
+ l <- createLockFile mode lockfile
+ waitToSetLock l (lockreq, AbsoluteSeek, 0, 0)
+ return (LockHandle l)
+
+-- Create and opens lock file, does not lock it.
+-- Close on exec flag is set so child processes do not inherit the lock.
+createLockFile :: Maybe FileMode -> LockFile -> IO Fd
+createLockFile mode lockfile = do
+ l <- openFd lockfile ReadWrite mode defaultFileFlags
+ setFdOption l CloseOnExec True
+ return l
+
+dropLock :: LockHandle -> IO ()
+dropLock (LockHandle fd) = closeFd fd
diff --git a/Utility/WinLock.hs b/Utility/LockFile/Windows.hs
index fc7c8a8a9..73c248b03 100644
--- a/Utility/WinLock.hs
+++ b/Utility/LockFile/Windows.hs
@@ -5,7 +5,7 @@
- License: BSD-2-clause
-}
-module Utility.WinLock (
+module Utility.LockFile.Windows (
lockShared,
lockExclusive,
dropLock,
@@ -17,9 +17,6 @@ import System.Win32.Types
import System.Win32.File
import Control.Concurrent
-{- Locking is exclusive, and prevents the file from being opened for read
- - or write by any other process. So for advisory locking of a file, a
- - different LockFile should be used. -}
type LockFile = FilePath
type LockHandle = HANDLE
@@ -30,7 +27,11 @@ lockShared :: LockFile -> IO (Maybe LockHandle)
lockShared = openLock fILE_SHARE_READ
{- Tries to take an exclusive lock on a file. Fails if another process has
- - a shared or exclusive lock. -}
+ - a shared or exclusive lock.
+ -
+ - Note that exclusive locking also prevents the file from being opened for
+ - read or write by any other progess. So for advisory locking of a file's
+ - content, a different LockFile should be used. -}
lockExclusive :: LockFile -> IO (Maybe LockHandle)
lockExclusive = openLock fILE_SHARE_NONE