halfs-0.2: Haskell File System Source code Contents Index

Halfs Portability GHC Stability alpha Maintainer Isaac Jones <ijones@galois.com>

Contents Write-related functions Read-related functions Meta-data functions Creating new filesystems Mounting filesystems Evaluating the FSRead and FSWrite moands fsck Types (most are re-exported from elsewhere) Types to make abstract (FIX) testing

Description

High-level interface to Halfs, the Haskell Filesystem.

Synopsis

unlink :: FilePath -> FSWrite () rmdir :: FilePath -> FSWrite () rename :: FilePath -> FilePath -> FSWrite () mkdir :: FilePath -> FSWrite () addChildWrite :: Directory -> Inode -> String -> FSWrite Inode openWrite :: FilePath -> FSWrite FileHandle openAppend :: FilePath -> FSWrite FileHandle write :: FileHandle -> Buffer -> INInt -> INInt -> FSWrite INInt writeString :: FileHandle -> String -> FSWrite INInt closeWrite :: FileHandle -> FSWrite () openFileAtPathWrite :: FileMode -> FilePath -> FileType -> Bool -> FSWrite FileHandle stat :: FilePath -> FSRead RdStat fstat :: FileHandle -> FSRead RdStat openRead :: FilePath -> FSRead FileHandle read :: FileHandle -> Buffer -> INInt -> INInt -> FSRead INInt closeRead :: FileHandle -> FSRead () seek :: FileHandle -> INLong -> FSRead () openFileAtPathRead :: FilePath -> FSRead FileHandle fsStats :: FSRoot -> IO FileSystemStats getDirectoryContents :: FilePath -> FSRead [FilePath] isDirectory :: FilePath -> FSRead Bool getDirectoryDetails :: FilePath -> FSRead [(String, Inode)] newFS :: DeviceLocation -> INInt -> IO () withNewFSWrite :: String -> INInt -> FSWrite a -> IO a mountFS :: Maybe StateHandle -> DeviceLocation -> Bool -> Int -> IO FSRoot unmountFS :: FSRoot -> IO () unmountWriteFS :: FSWrite () mountFSMV :: Maybe StateHandle -> DeviceLocation -> Maybe (MVar ()) -> Bool -> Int -> IO StateHandle withFSRead :: DeviceLocation -> FSRead a -> IO a withFSWrite :: DeviceLocation -> FSWrite a -> IO a evalFSWriteIOMV :: FSWrite a -> StateHandle -> IO a evalFSReadIOMV :: FSRead a -> StateHandle -> IO a fsck :: DeviceLocation -> IO () fsckWrite :: FSWrite () syncPeriodicallyWrite :: MVar () -> Bool -> FSWrite () readReadRef :: ReadRef a -> FSRead a data FSWrite a data FSRead a newtype TimeT = TimeT CLong type SizeT = INLong type FileHandle = IORef FileHandle data FileMode = ReadMode | WriteMode | AppendMode data Buffer type DeviceLocation = String data InodeMetadata = InodeMetadata { magic1 :: INInt num_bytes :: INLong uid :: INInt gid :: INInt mode :: FileType inode_num :: INInt flags :: INInt hard_links :: INInt create_time :: INLong last_modified_time :: INLong level :: INInt } data Inode = Inode { metaData :: InodeMetadata blockPtrs :: INPointers } data StateHandle = StateHandle { stateFineMVar :: MVar FSRoot stateCoarseMVar :: Maybe (MVar ()) } data RdStat = RdDirectory { modTime :: TimeT } | RdFile { modTime :: TimeT size :: SizeT } data FileSystemStats = FileSystemStats { blockSize :: Integer blockCount :: Integer blocksFree :: Integer blocksAvailable :: Integer fileCount :: Integer filesFree :: Integer maxNameLength :: Integer } data FSStatus = FsUnmounted | FsReadOnly | FsReadWrite makeFiles :: Int -> FilePath -> String -> FSWrite () unitTests :: Bool -> UnitTests

Write-related functions

unlink :: FilePath -> FSWrite () Source

Delete this file. Currently can be used to delete a directory, but that should probably be FIXED.

rmdir :: FilePath -> FSWrite () Source

Unlink this directory. Should only be called on empty directories. Does not descent into sub-directories. Should fail if given a file or if the directory is non-empty (but currently doesn't: FIX).

rename Source

:: FilePath From -> FilePath To -> FSWrite () Rename this file. Rename the file named as From to the file named as To. Can throw an exception if From doesn't exist.

mkdir :: FilePath -> FSWrite () Source

Create an empty directory at this path. Throws an error if something already exists at this path.

addChildWrite Source

:: Directory to add to directory -> Inode new child's inode -> String Name of child to create inside directory. -> FSWrite Inode Like Direcotry.addChild, but in the FSWrite monad, and syncs this directory.

openWrite :: FilePath -> FSWrite FileHandle Source

Open the given file for writing. If a file exists at this location, it gets overwritten. FIX: Test

openAppend :: FilePath -> FSWrite FileHandle Source

Open the given file for appending. If a file already exists at this location, it gets opened for writing, and the file pointer is pointing to the end. FIX: Test, what does it do if no such file exists.

write Source

:: FileHandle -> Buffer Buffer to write from -> INInt Offset into above buffer FIX: should we allow current loc -> INInt How many to write -> FSWrite INInt Write from the given buffer into the file.

writeString :: FileHandle -> String -> FSWrite INInt Source

Helpfer function for writing a string to a file.

closeWrite :: FileHandle -> FSWrite () Source

Close a file that's open for writing.

openFileAtPathWrite :: FileMode -> FilePath -> FileType -> Bool -> FSWrite FileHandle Source

Much like getDirectoryAtPath, builds a handle out of this filepath. May throw IO Error! FIX: annotate w/ errors thrown. FIX: throw errors for incorrect mode.

Read-related functions

stat :: FilePath -> FSRead RdStat Source

Get basic information about the file at this path.

fstat :: FileHandle -> FSRead RdStat Source

Get basic information about this file handle.

openRead :: FilePath -> FSRead FileHandle Source

Open this file for reading. FIX: test.

read Source

:: FileHandle -> Buffer Buffer to read into -> INInt Offset into above buffer -> INInt How many to read -> FSRead INInt Read from this file handle into this buffer.

closeRead :: FileHandle -> FSRead () Source

Close a filehandle that's open for reading.

seek Source

:: FileHandle -> INLong What byte offset to move the filehandle to. Must be > 0 and < the number of bytes in the file. -> FSRead () Move this filehandle to given position.

openFileAtPathRead :: FilePath -> FSRead FileHandle Source

Meta-data functions

fsStats :: FSRoot -> IO FileSystemStats Source

getDirectoryContents :: FilePath -> FSRead [FilePath] Source

Get the contents of a directory.

isDirectory :: FilePath -> FSRead Bool Source

Does this filepath refer to a directory?

getDirectoryDetails :: FilePath -> FSRead [(String, Inode)] Source

Caller may want to filter out . and ..

Creating new filesystems

newFS Source

:: DeviceLocation -> INInt desired length of the new filesystem in blocks -> IO () Creates a new filesystem with a real-life root inode! Out of thin air, create a buffer block for this device, 0, and write root inode to our new cache.

withNewFSWrite Source

:: => String -> INInt -> FSWrite a Operations to perform -> IO a Create a new file system and perform the given operations. Unmounting is up to the caller. See newFS for parameter details.

Mounting filesystems

mountFS Source

:: Maybe StateHandle if Just, use the raw device inside -> DeviceLocation Location of device -> Bool Read only? -> Int buffer block cache size -> IO FSRoot Basic low-level mount operation. Usually used via wrappers such as withFSWrite and withFSRead. See also newFS.

unmountFS :: FSRoot -> IO () Source

Syncs the device and closes its handle. You should stop using it after that. Must represent an open device!

unmountWriteFS :: FSWrite () Source

Just like unmountFS but in the FSWrite monad.

mountFSMV Source

:: Maybe StateHandle -> DeviceLocation -> Maybe (MVar ()) the outermost-blocker, if desirable. causes a synchronization thread to be spawned -> Bool -> Int cache size -> IO StateHandle See mountFS for most documentation.

withFSRead Source

:: => DeviceLocation Location of device -> FSRead a Operations to perform -> IO a Mount the given file system for reading and perform these operations.

withFSWrite Source

:: => DeviceLocation Location of device -> FSWrite a Operations to perform -> IO a Mount the given file system for writing and perform these operations. FIX: Maybe add MVar () for blocking on.

Evaluating the FSRead and FSWrite moands

evalFSWriteIOMV :: FSWrite a -> StateHandle -> IO a Source

evalFSReadIOMV :: FSRead a -> StateHandle -> IO a Source

fsck

fsck :: DeviceLocation -> IO () Source

Check the filesystem for errors. Exits with an error code and message if any are found. Outputs lots of low-level data to the terminal.

fsckWrite :: FSWrite () Source

See fsck.

syncPeriodicallyWrite Source

:: MVar () High-level blocker. This function blocks on this mvar. -> Bool -> FSWrite () Periodically sync the filesystem. Usually forked off in its own thread. For READS: Flush caches on read-only filesystem (so they'll be re-populated). For WRITES: write out the filesystem data. FIX: remove readOnly; that's in the fsroot. FIX: add exception handler (since it does a take)

readReadRef :: ReadRef a -> FSRead a Source

Types (most are re-exported from elsewhere)

data FSWrite a Source

Instances Monad FSWrite FSRW FSWrite MonadError IOError FSWrite MonadState FSRoot FSWrite

data FSRead a Source

Instances Monad FSRead FSRW FSRead MonadError IOError FSRead

newtype TimeT Source

Constructors TimeT CLong Instances Eq TimeT Ord TimeT Read TimeT Show TimeT Storable TimeT

type SizeT = INLong Source

type FileHandle = IORef FileHandle Source

data FileMode Source

Constructors ReadMode WriteMode AppendMode Instances Eq FileMode Show FileMode

data Buffer Source

type DeviceLocation = String Source

The location of a device might be a path to the device on a Linux filesystem.

data InodeMetadata Source

Constructors InodeMetadata magic1 :: INInt num_bytes :: INLong uid :: INInt gid :: INInt mode :: FileType file or dir inode_num :: INInt flags :: INInt hard_links :: INInt persistent references create_time :: INLong last_modified_time :: INLong level :: INInt Instances Eq InodeMetadata Show InodeMetadata Binary InodeMetadata

data Inode Source

Constructors Inode metaData :: InodeMetadata blockPtrs :: INPointers Instances Eq Inode Show Inode Binary Inode

Types to make abstract (FIX)

data StateHandle Source

Read-write state Constructors StateHandle stateFineMVar :: MVar FSRoot stateCoarseMVar :: Maybe (MVar ()) Instances Eq StateHandle

data RdStat Source

This seems to be the kind of Stat information needed by the TSE front end. Constructors RdDirectory modTime :: TimeT RdFile modTime :: TimeT size :: SizeT Instances Eq RdStat Show RdStat

data FileSystemStats Source

Constructors FileSystemStats blockSize :: Integer Optimal transfer block size in bytes. blockCount :: Integer Total data blocks in file system. blocksFree :: Integer Free blocks in file system. blocksAvailable :: Integer Free blocks available to non-superusers. fileCount :: Integer Total file nodes in file system. filesFree :: Integer Free file nodes in file system. maxNameLength :: Integer Maximum length of filenames. FUSE default is 255.

data FSStatus Source

Constructors FsUnmounted FsReadOnly FsReadWrite Instances Eq FSStatus Show FSStatus

testing

makeFiles Source

:: Int Number of files -> FilePath Where to put them -> String -> FSWrite () for testing. Create some files in the given directory

unitTests :: Bool -> UnitTests Source

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