Haskell Hierarchical Libraries (unix package)Source codeContentsIndex
System.Posix.Files
Portabilitynon-portable (requires POSIX)
Stabilityprovisional
Maintainerlibraries@haskell.org
Contents
File modes
Setting file modes
Checking file existence and permissions
File status
Obtaining file status
Querying file status
Creation
Hard links
Symbolic links
Renaming files
Changing file ownership
Changing file timestamps
Setting file sizes
Find system-specific limits for a file
Description

Functions defined by the POSIX standards for manipulating and querying the file system. Names of underlying POSIX functions are indicated whenever possible. A more complete documentation of the POSIX functions together with a more detailed description of different error conditions are usually available in the system's manual pages or from http://www.unix.org/version3/online.html (free registration required).

When a function that calls an underlying POSIX function fails, the errno code is converted to an IOError using errnoToIOError. For a list of which errno codes may be generated, consult the POSIX documentation for the underlying function.

Synopsis
unionFileModes :: FileMode -> FileMode -> FileMode
intersectFileModes :: FileMode -> FileMode -> FileMode
nullFileMode :: FileMode
ownerReadMode :: FileMode
ownerWriteMode :: FileMode
ownerExecuteMode :: FileMode
ownerModes :: FileMode
groupReadMode :: FileMode
groupWriteMode :: FileMode
groupExecuteMode :: FileMode
groupModes :: FileMode
otherReadMode :: FileMode
otherWriteMode :: FileMode
otherExecuteMode :: FileMode
otherModes :: FileMode
setUserIDMode :: FileMode
setGroupIDMode :: FileMode
stdFileMode :: FileMode
accessModes :: FileMode
setFileMode :: FilePath -> FileMode -> IO ()
setFdMode :: Fd -> FileMode -> IO ()
setFileCreationMask :: FileMode -> IO FileMode
fileAccess :: FilePath -> Bool -> Bool -> Bool -> IO Bool
fileExist :: FilePath -> IO Bool
data FileStatus
getFileStatus :: FilePath -> IO FileStatus
getFdStatus :: Fd -> IO FileStatus
getSymbolicLinkStatus :: FilePath -> IO FileStatus
deviceID :: FileStatus -> DeviceID
fileID :: FileStatus -> FileID
fileMode :: FileStatus -> FileMode
linkCount :: FileStatus -> LinkCount
fileOwner :: FileStatus -> UserID
fileGroup :: FileStatus -> GroupID
specialDeviceID :: FileStatus -> DeviceID
fileSize :: FileStatus -> FileOffset
accessTime :: FileStatus -> EpochTime
modificationTime :: FileStatus -> EpochTime
statusChangeTime :: FileStatus -> EpochTime
isBlockDevice :: FileStatus -> Bool
isCharacterDevice :: FileStatus -> Bool
isNamedPipe :: FileStatus -> Bool
isRegularFile :: FileStatus -> Bool
isDirectory :: FileStatus -> Bool
isSymbolicLink :: FileStatus -> Bool
isSocket :: FileStatus -> Bool
createNamedPipe :: FilePath -> FileMode -> IO ()
createDevice :: FilePath -> FileMode -> DeviceID -> IO ()
createLink :: FilePath -> FilePath -> IO ()
removeLink :: FilePath -> IO ()
createSymbolicLink :: FilePath -> FilePath -> IO ()
readSymbolicLink :: FilePath -> IO FilePath
rename :: FilePath -> FilePath -> IO ()
setOwnerAndGroup :: FilePath -> UserID -> GroupID -> IO ()
setFdOwnerAndGroup :: Fd -> UserID -> GroupID -> IO ()
setSymbolicLinkOwnerAndGroup :: FilePath -> UserID -> GroupID -> IO ()
setFileTimes :: FilePath -> EpochTime -> EpochTime -> IO ()
touchFile :: FilePath -> IO ()
setFileSize :: FilePath -> FileOffset -> IO ()
setFdSize :: Fd -> FileOffset -> IO ()
data PathVar
= FileSizeBits
| LinkLimit
| InputLineLimit
| InputQueueLimit
| FileNameLimit
| PathNameLimit
| PipeBufferLimit
| SymbolicLinkLimit
| SetOwnerAndGroupIsRestricted
| FileNamesAreNotTruncated
| VDisableChar
| AsyncIOAvailable
| PrioIOAvailable
| SyncIOAvailable
getPathVar :: FilePath -> PathVar -> IO Limit
getFdPathVar :: Fd -> PathVar -> IO Limit
File modes
unionFileModes :: FileMode -> FileMode -> FileMode
Combines the two file modes into one that contains modes that appear in either.
intersectFileModes :: FileMode -> FileMode -> FileMode
Combines two file modes into one that only contains modes that appear in both.
nullFileMode :: FileMode
No permissions.
ownerReadMode :: FileMode
Owner has read permission.
ownerWriteMode :: FileMode
Owner has write permission.
ownerExecuteMode :: FileMode
Owner has execute permission.
ownerModes :: FileMode
Owner has read, write and execute permission.
groupReadMode :: FileMode
Group has read permission.
groupWriteMode :: FileMode
Group has write permission.
groupExecuteMode :: FileMode
Group has execute permission.
groupModes :: FileMode
Group has read, write and execute permission.
otherReadMode :: FileMode
Others have read permission.
otherWriteMode :: FileMode
Others have write permission.
otherExecuteMode :: FileMode
Others have execute permission.
otherModes :: FileMode
Others have read, write and execute permission.
setUserIDMode :: FileMode
Set user ID on execution.
setGroupIDMode :: FileMode
Set group ID on execution.
stdFileMode :: FileMode
Owner, group and others have read and write permission.
accessModes :: FileMode
Owner, group and others have read, write and execute permission.
Setting file modes
setFileMode :: FilePath -> FileMode -> IO ()

setFileMode path mode changes permission of the file given by path to mode. This operation may fail with throwErrnoPathIfMinus1_ if path doesn't exist or if the effective user ID of the current process is not that of the file's owner.

Note: calls chmod.

setFdMode :: Fd -> FileMode -> IO ()

setFdMode fd mode acts like setFileMode but uses a file descriptor fd instead of a FilePath.

Note: calls fchmod.

setFileCreationMask :: FileMode -> IO FileMode

setFileCreationMask mode sets the file mode creation mask to mode. Modes set by this operation are subtracted from files and directories upon creation. The previous file creation mask is returned.

Note: calls umask.

Checking file existence and permissions
fileAccess :: FilePath -> Bool -> Bool -> Bool -> IO Bool

fileAccess name read write exec checks if the file (or other file system object) name can be accessed for reading, writing and/or executing. To check a permission set the corresponding argument to True.

Note: calls access.

fileExist :: FilePath -> IO Bool

Checks for the existence of the file.

Note: calls access.

File status
data FileStatus

POSIX defines operations to get information, such as owner, permissions, size and access times, about a file. This information is represented by the FileStatus type.

Note: see chmod.

Obtaining file status
getFileStatus :: FilePath -> IO FileStatus

getFileStatus path calls gets the FileStatus information (user ID, size, access times, etc.) for the file path.

Note: calls stat.

getFdStatus :: Fd -> IO FileStatus

getFdStatus fd acts as getFileStatus but uses a file descriptor fd.

Note: calls fstat.

getSymbolicLinkStatus :: FilePath -> IO FileStatus

Acts as getFileStatus except when the FilePath refers to a symbolic link. In that case the FileStatus information of the symbolic link itself is returned instead of that of the file it points to.

Note: calls lstat.

Querying file status
deviceID :: FileStatus -> DeviceID
ID of the device on which this file resides.
fileID :: FileStatus -> FileID
inode number
fileMode :: FileStatus -> FileMode
File mode (such as permissions).
linkCount :: FileStatus -> LinkCount
Number of hard links to this file.
fileOwner :: FileStatus -> UserID
ID of owner.
fileGroup :: FileStatus -> GroupID
ID of group.
specialDeviceID :: FileStatus -> DeviceID
Describes the device that this file represents.
fileSize :: FileStatus -> FileOffset
Size of the file in bytes. If this file is a symbolic link the size is the length of the pathname it contains.
accessTime :: FileStatus -> EpochTime
Time of last access.
modificationTime :: FileStatus -> EpochTime
Time of last modification.
statusChangeTime :: FileStatus -> EpochTime
Time of last status change (i.e. owner, group, link count, mode, etc.).
isBlockDevice :: FileStatus -> Bool
Checks if this file is a block device.
isCharacterDevice :: FileStatus -> Bool
Checks if this file is a character device.
isNamedPipe :: FileStatus -> Bool
Checks if this file is a named pipe device.
isRegularFile :: FileStatus -> Bool
Checks if this file is a regular file device.
isDirectory :: FileStatus -> Bool
Checks if this file is a directory device.
isSymbolicLink :: FileStatus -> Bool
Checks if this file is a symbolic link device.
isSocket :: FileStatus -> Bool
Checks if this file is a socket device.
Creation
createNamedPipe :: FilePath -> FileMode -> IO ()

createNamedPipe fifo mode creates a new named pipe, fifo, with permissions based on mode. May fail with throwErrnoPathIfMinus1_ if a file named name already exists or if the effective user ID of the current process doesn't have permission to create the pipe.

Note: calls mkfifo.

createDevice :: FilePath -> FileMode -> DeviceID -> IO ()

createDevice path mode dev creates either a regular or a special file depending on the value of mode (and dev). May fail with throwErrnoPathIfMinus1_ if a file named name already exists or if the effective user ID of the current process doesn't have permission to create the file.

Note: calls mknod.

Hard links
createLink :: FilePath -> FilePath -> IO ()

createLink old new creates a new path, new, linked to an existing file, old.

Note: calls link.

removeLink :: FilePath -> IO ()

removeLink path removes the link named path.

Note: calls unlink.

Symbolic links
createSymbolicLink :: FilePath -> FilePath -> IO ()

createSymbolicLink file1 file2 creates a symbolic link named file2 which points to the file file1.

Symbolic links are interpreted at run-time as if the contents of the link had been substituted into the path being followed to find a file or directory.

Note: calls symlink.

readSymbolicLink :: FilePath -> IO FilePath

Reads the FilePath pointed to by the symbolic link and returns it.

Note: calls readlink.

Renaming files
rename :: FilePath -> FilePath -> IO ()

rename old new renames a file or directory from old to new.

Note: calls rename.

Changing file ownership
setOwnerAndGroup :: FilePath -> UserID -> GroupID -> IO ()

setOwnerAndGroup path uid gid changes the owner and group of path to uid and gid, respectively.

If uid or gid is specified as -1, then that ID is not changed.

Note: calls chown.

setFdOwnerAndGroup :: Fd -> UserID -> GroupID -> IO ()

Acts as setOwnerAndGroup but uses a file descriptor instead of a FilePath.

Note: calls fchown.

setSymbolicLinkOwnerAndGroup :: FilePath -> UserID -> GroupID -> IO ()

Acts as setOwnerAndGroup but does not follow symlinks (and thus changes permissions on the link itself).

Note: calls lchown.

Changing file timestamps
setFileTimes :: FilePath -> EpochTime -> EpochTime -> IO ()

setFileTimes path atime mtime sets the access and modification times associated with file path to atime and mtime, respectively.

Note: calls utime.

touchFile :: FilePath -> IO ()

touchFile path sets the access and modification times associated with file path to the current time.

Note: calls utime.

Setting file sizes
setFileSize :: FilePath -> FileOffset -> IO ()

Truncates the file down to the specified length. If the file was larger than the given length before this operation was performed the extra is lost.

Note: calls truncate.

setFdSize :: Fd -> FileOffset -> IO ()

Acts as setFileSize but uses a file descriptor instead of a FilePath.

Note: calls ftruncate.

Find system-specific limits for a file
data PathVar
Constructors
FileSizeBits
LinkLimit
InputLineLimit
InputQueueLimit
FileNameLimit
PathNameLimit
PipeBufferLimit
SymbolicLinkLimit
SetOwnerAndGroupIsRestricted
FileNamesAreNotTruncated
VDisableChar
AsyncIOAvailable
PrioIOAvailable
SyncIOAvailable
getPathVar :: FilePath -> PathVar -> IO Limit

getPathVar var path obtains the dynamic value of the requested configurable file limit or option associated with file or directory path. For defined file limits, getPathVar returns the associated value. For defined file options, the result of getPathVar is undefined, but not failure.

Note: calls pathconf.

getFdPathVar :: Fd -> PathVar -> IO Limit

getFdPathVar var fd obtains the dynamic value of the requested configurable file limit or option associated with the file or directory attached to the open channel fd. For defined file limits, getFdPathVar returns the associated value. For defined file options, the result of getFdPathVar is undefined, but not failure.

Note: calls fpathconf.

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