System.Linux.XAttr

linux-xattr provides bindings to the Linux syscalls for reading and manipulating extended attributes (setxattr, getxattr, listxattr and removexattr).

Each function in this module has two variants: one with the name prefixed by __l__ and one prefixed by __fd__. Both of these are identical to the original version except that the __l__-variant does not follow symbolic link but acts on the link itself, and the __fd__-variant take a file descriptor as argument rather than a FilePath.

Moreover, every function has an xxx__UserXAttr__ variant for working transparently in the __user__ namespace of extended attributes, without worrying about the user. prefix: these functions automatically prepends the string user. to the Name of the attribute when Name is an input value, or strip the prefix user. from it when Name is a returned value. See the documentation of each individual function for details.

Set extended attributes

Functions in this section call the setxattr syscall.

setXAttr :: FilePath -> Name -> Value -> IO ()

Set the Value of the extended attribute identified by Name and associated with the given FilePath in the filesystem.

lSetXAttr :: FilePath -> Name -> Value -> IO ()

Set the Value of the extended attribute identified by Name and associated with the given FilePath in the filesystem (do not follow symbolic links).

fdSetXAttr :: Fd -> Name -> Value -> IO ()

Set the Value of the extended attribute identified by Name and associated with the given file descriptor in the filesystem.

Set extended user attributes

setUserXAttr :: FilePath -> Name -> Value -> IO ()

setUserXAttr /some/path foo bar = setXAttr /some/path user.foo bar

lSetUserXAttr :: FilePath -> Name -> Value -> IO ()

lSetUserXAttr /some/link foo bar = lSetXAttr /some/link user.foo bar

fdSetUserXAttr :: Fd -> Name -> Value -> IO ()

fdSetUserXAttr (Fd n) foo bar = fdSetXAttr (Fd n) user.foo bar

Create extended attributes

Functions in this section call the setxattr syscall with the flag XATTR_CREATE.

createXAttr :: FilePath -> Name -> Value -> IO ()

Identical to setXAttr, but if the attribute already exists fail with isAlreadyExistsError.

lCreateXAttr :: FilePath -> Name -> Value -> IO ()

Identical to lSetXAttr, but if the attribute already exists fail with isAlreadyExistsError.

fdCreateXAttr :: Fd -> Name -> Value -> IO ()

Identical to fdSetXAttr, but if the attribute already exists fail with isAlreadyExistsError.

Create extended user attributes

createUserXAttr :: FilePath -> Name -> Value -> IO ()

createUserXAttr /some/path foo bar = createXAttr /some/path user.foo bar

lCreateUserXAttr :: FilePath -> Name -> Value -> IO ()

lCreateUserXAttr /some/link foo bar = lCreateXAttr /some/link user.foo bar

fdCreateUserXAttr :: Fd -> Name -> Value -> IO ()

fdCreateUserXAttr (Fd n) foo bar = fdCreateXAttr (Fd n) user.foo bar

Replace extended attributes

Functions in this section call the setxattr syscall with the flag XATTR_REPLACE.

replaceXAttr :: FilePath -> Name -> Value -> IO ()

Identical to setXAttr, but if the attribute does not exist fail with isDoesNotExistError.

lReplaceXAttr :: FilePath -> Name -> Value -> IO ()

Identical to lSetXAttr, but if the attribute does not exist fail with isDoesNotExistError.

fdReplaceXAttr :: Fd -> Name -> Value -> IO ()

Identical to fdSetXAttr, but if the attribute does not exist fail with isDoesNotExistError.

Replace extended user attributes

replaceUserXAttr :: FilePath -> Name -> Value -> IO ()

replaceUserXAttr /some/path foo bar = replaceXAttr /some/path user.foo bar

lReplaceUserXAttr :: FilePath -> Name -> Value -> IO ()

lReplaceUserXAttr /some/link foo bar = lReplaceXAttr /some/link user.foo bar

fdReplaceUserXAttr :: Fd -> Name -> Value -> IO ()

fdReplaceUserXAttr (Fd n) foo bar = fdReplaceXAttr (Fd n) user.foo bar

Retrieve extended attributes

Functions in this section call the getxattr syscall.

getXAttr :: FilePath -> Name -> IO Value

Retrieve the Value of the extended attribute identified by Name and associated with the given FilePath in the filesystem, or fail with isDoesNotExistError if the attribute does not exist.

lGetXAttr :: FilePath -> Name -> IO Value

Retrieve the Value of the extended attribute identified by Name and associated with the given FilePath in the filesystem, or fail with isDoesNotExistError if the attribute does not exist (do not follow symbolic links).

fdGetXAttr :: Fd -> Name -> IO Value

Retrieve the Value of the extended attribute identified by Name and associated with the given file descriptor in the filesystem, or fail with isDoesNotExistError if the attribute does not exist.

Retrieve extended user attributes

getUserXAttr :: FilePath -> Name -> IO Value

getUserXAttr /some/path foo = getXAttr /some/path user.foo

lGetUserXAttr :: FilePath -> Name -> IO Value

lGetUserXAttr /some/link foo = lGetXAttr /some/link user.foo

fdGetUserXAttr :: Fd -> Name -> IO Value

fdGetUserXAttr (Fd n) foo = fdGetXAttr (Fd n) user.foo

List extended attributes

Functions in this section call the listxattr syscall.

listXAttr :: FilePath -> IO [Name]

Get the list of extended attribute Names associated with the given FilePath in the filesystem.

lListXAttr :: FilePath -> IO [Name]

Get the list of extended attribute Names associated with the given FilePath in the filesystem (do not follow symbolic links).

fdListXAttr :: Fd -> IO [Name]

Get the list of extended attribute Names associated with the given file descriptor in the filesystem.

List extended user attributes

These functions only list those extended attributes with Name beginning with user.. The user. prefix is removed from each Name in the output list.

listUserXAttr :: FilePath -> IO [Name]

lListUserXAttr :: FilePath -> IO [Name]

fdListUserXAttr :: Fd -> IO [Name]

Remove extended attributes

Functions in this section call the removexattr syscall.

removeXAttr :: FilePath -> Name -> IO ()

Remove the extended attribute identified by Name and associated with the given FilePath in the filesystem, or fail with isDoesNotExistError if the attribute does not exist.

lRemoveXAttr :: FilePath -> Name -> IO ()

Remove the extended attribute identified by Name and associated with the given FilePath in the filesystem, or fail with isDoesNotExistError if the attribute does not exist (do not follow symbolic links).

fdRemoveXAttr :: Fd -> Name -> IO ()

Remove the extended attribute identified by Name and associated with the given file descriptor in the filesystem, or fail with isDoesNotExistError if the attribute does not exist.

Remove extended user attributes

removeUserXAttr :: FilePath -> Name -> IO ()

removeUserXAttr /some/path foo = removeXAttr /some/path user.foo

lRemoveUserXAttr :: FilePath -> Name -> IO ()

lRemoveUserXAttr /some/link foo = lRemoveXAttr /some/link user.foo

fdRemoveUserXAttr :: Fd -> Name -> IO ()

fdRemoveUserXAttr (Fd n) foo = fdRemoveXAttr (Fd n) user.foo

Types for extended attributes

type Name = String

Name of extended attribute.

type Value = ByteString

Value of extended attribute.