40ecf58d4b
This does not change the overall license of the git-annex program, which was already AGPL due to a number of sources files being AGPL already. Legally speaking, I'm adding a new license under which these files are now available; I already released their current contents under the GPL license. Now they're dual licensed GPL and AGPL. However, I intend for all my future changes to these files to only be released under the AGPL license, and I won't be tracking the dual licensing status, so I'm simply changing the license statement to say it's AGPL. (In some cases, others wrote parts of the code of a file and released it under the GPL; but in all cases I have contributed a significant portion of the code in each file and it's that code that is getting the AGPL license; the GPL license of other contributors allows combining with AGPL code.)
97 lines
3 KiB
Haskell
97 lines
3 KiB
Haskell
{- Wraps Utility.LockPool, making pid locks be used when git-annex is so
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- configured.
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-
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- Copyright 2015 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Annex.LockPool.PosixOrPid (
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LockFile,
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LockHandle,
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lockShared,
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lockExclusive,
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tryLockShared,
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tryLockExclusive,
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dropLock,
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checkLocked,
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LockStatus(..),
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getLockStatus,
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checkSaneLock,
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) where
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import Common
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import Types
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import Annex.Locations
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import qualified Annex
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import qualified Utility.LockPool.Posix as Posix
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import qualified Utility.LockPool.PidLock as Pid
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import qualified Utility.LockPool.LockHandle as H
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import Utility.LockPool.LockHandle (LockHandle, dropLock)
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import Utility.LockFile.Posix (openLockFile)
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import Utility.LockPool.STM (LockFile)
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import Utility.LockFile.LockStatus
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import System.Posix
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lockShared :: Maybe FileMode -> LockFile -> Annex LockHandle
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lockShared m f = pidLock m f $ Posix.lockShared m f
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lockExclusive :: Maybe FileMode -> LockFile -> Annex LockHandle
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lockExclusive m f = pidLock m f $ Posix.lockExclusive m f
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tryLockShared :: Maybe FileMode -> LockFile -> Annex (Maybe LockHandle)
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tryLockShared m f = tryPidLock m f $ Posix.tryLockShared m f
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tryLockExclusive :: Maybe FileMode -> LockFile -> Annex (Maybe LockHandle)
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tryLockExclusive m f = tryPidLock m f $ Posix.tryLockExclusive m f
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checkLocked :: LockFile -> Annex (Maybe Bool)
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checkLocked f = Posix.checkLocked f `pidLockCheck` checkpid
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where
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checkpid pidlock = Pid.checkLocked pidlock >>= \case
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-- Only return true when the posix lock file exists.
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Just _ -> Posix.checkLocked f
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Nothing -> return Nothing
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getLockStatus :: LockFile -> Annex LockStatus
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getLockStatus f = Posix.getLockStatus f
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`pidLockCheck` Pid.getLockStatus
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checkSaneLock :: LockFile -> LockHandle -> Annex Bool
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checkSaneLock f h = H.checkSaneLock f h
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`pidLockCheck` flip Pid.checkSaneLock h
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pidLockFile :: Annex (Maybe FilePath)
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pidLockFile = ifM (annexPidLock <$> Annex.getGitConfig)
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( Just <$> Annex.fromRepo gitAnnexPidLockFile
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, pure Nothing
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)
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pidLockCheck :: IO a -> (LockFile -> IO a) -> Annex a
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pidLockCheck posixcheck pidcheck = debugLocks $
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liftIO . maybe posixcheck pidcheck =<< pidLockFile
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pidLock :: Maybe FileMode -> LockFile -> IO LockHandle -> Annex LockHandle
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pidLock m f posixlock = debugLocks $ go =<< pidLockFile
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where
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go Nothing = liftIO posixlock
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go (Just pidlock) = do
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timeout <- annexPidLockTimeout <$> Annex.getGitConfig
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liftIO $ do
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dummyPosixLock m f
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Pid.waitLock timeout pidlock
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tryPidLock :: Maybe FileMode -> LockFile -> IO (Maybe LockHandle) -> Annex (Maybe LockHandle)
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tryPidLock m f posixlock = debugLocks $ liftIO . go =<< pidLockFile
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where
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go Nothing = posixlock
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go (Just pidlock) = do
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dummyPosixLock m f
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Pid.tryLock pidlock
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-- The posix lock file is created even when using pid locks, in order to
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-- avoid complicating any code that might expect to be able to see that
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-- lock file. But, it's not locked.
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dummyPosixLock :: Maybe FileMode -> LockFile -> IO ()
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dummyPosixLock m f = closeFd =<< openLockFile ReadLock m f
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