2 % (c) The AQUA Project, Glasgow University, 1994-1997
4 \section[Directory]{Directory interface}
6 A directory contains a series of entries, each of which is a named
7 reference to a file system object (file, directory etc.). Some
8 entries may be hidden, inaccessible, or have some administrative
9 function (e.g. "." or ".." under POSIX), but in this standard all such
10 entries are considered to form part of the directory contents.
11 Entries in sub-directories are not, however, considered to form part
12 of the directory contents.
14 Each file system object is referenced by a {\em path}. There is
15 normally at least one absolute path to each file system object. In
16 some operating systems, it may also be possible to have paths which
17 are relative to the current directory.
20 {-# OPTIONS -#include <sys/stat.h> -#include <dirent.h> #-}
23 Permissions(Permissions),
45 import PrelUnsafe ( unsafePerformIO )
47 import PrelPack ( unpackNBytesST )
48 import PrelForeign ( Word(..) )
50 import Time ( ClockTime(..) )
54 %*********************************************************
56 \subsection{Signatures}
58 %*********************************************************
61 createDirectory :: FilePath -> IO ()
62 removeDirectory :: FilePath -> IO ()
63 removeFile :: FilePath -> IO ()
64 renameDirectory :: FilePath -> FilePath -> IO ()
65 renameFile :: FilePath -> FilePath -> IO ()
66 getDirectoryContents :: FilePath -> IO [FilePath]
67 getCurrentDirectory :: IO FilePath
68 setCurrentDirectory :: FilePath -> IO ()
69 doesFileExist :: FilePath -> IO Bool
70 doesDirectoryExist :: FilePath -> IO Bool
71 getPermissions :: FilePath -> IO Permissions
72 setPermissions :: FilePath -> Permissions -> IO ()
73 getModificationTime :: FilePath -> IO ClockTime
77 %*********************************************************
79 \subsection{Permissions}
81 %*********************************************************
83 The @Permissions@ type is used to record whether certain
84 operations are permissible on a file/directory:
85 [to whom? - owner/group/world - the Report don't say much]
91 executable, searchable :: Bool
92 } deriving (Eq, Ord, Read, Show)
95 %*********************************************************
97 \subsection{Implementation}
99 %*********************************************************
101 @createDirectory dir@ creates a new directory {\em dir} which is
102 initially empty, or as near to empty as the operating system
105 The operation may fail with:
108 \item @isPermissionError@ / @PermissionDenied@
109 The process has insufficient privileges to perform the operation.
111 \item @isAlreadyExistsError@ / @AlreadyExists@
112 The operand refers to a directory that already exists.
114 \item @HardwareFault@
115 A physical I/O error has occurred.
117 \item @InvalidArgument@
118 The operand is not a valid directory name.
119 @[ENAMETOOLONG, ELOOP]@
121 There is no path to the directory.
123 \item @ResourceExhausted@
124 Insufficient resources (virtual memory, process file descriptors,
125 physical disk space, etc.) are available to perform the operation.
126 @[EDQUOT, ENOSPC, ENOMEM, EMLINK]@
127 \item @InappropriateType@
128 The path refers to an existing non-directory object.
133 createDirectory path = do
134 rc <- _ccall_ createDirectory path
135 if rc == 0 then return () else
136 constructErrorAndFail "createDirectory"
139 @removeDirectory dir@ removes an existing directory {\em dir}. The
140 implementation may specify additional constraints which must be
141 satisfied before a directory can be removed (e.g. the directory has to
142 be empty, or may not be in use by other processes). It is not legal
143 for an implementation to partially remove a directory unless the
144 entire directory is removed. A conformant implementation need not
145 support directory removal in all situations (e.g. removal of the root
148 The operation may fail with:
150 \item @HardwareFault@
151 A physical I/O error has occurred.
153 \item @InvalidArgument@
154 The operand is not a valid directory name.
155 @[ENAMETOOLONG, ELOOP]@
156 \item @isDoesNotExist@ / @NoSuchThing@
157 The directory does not exist.
159 \item @isPermissionError@ / @PermissionDenied@
160 The process has insufficient privileges to perform the operation.
161 @[EROFS, EACCES, EPERM]@
162 \item @UnsatisfiedConstraints@
163 Implementation-dependent constraints are not satisfied.
164 @[EBUSY, ENOTEMPTY, EEXIST]@
165 \item @UnsupportedOperation@
166 The implementation does not support removal in this situation.
168 \item @InappropriateType@
169 The operand refers to an existing non-directory object.
174 removeDirectory path = do
175 rc <- _ccall_ removeDirectory path
179 constructErrorAndFail "removeDirectory"
182 @removeFile file@ removes the directory entry for an existing file
183 {\em file}, where {\em file} is not itself a directory. The
184 implementation may specify additional constraints which must be
185 satisfied before a file can be removed (e.g. the file may not be in
186 use by other processes).
188 The operation may fail with:
190 \item @HardwareFault@
191 A physical I/O error has occurred.
193 \item @InvalidArgument@
194 The operand is not a valid file name.
195 @[ENAMETOOLONG, ELOOP]@
196 \item @isDoesNotExist@ / @NoSuchThing@
197 The file does not exist.
199 \item @isPermissionError@ / @PermissionDenied@
200 The process has insufficient privileges to perform the operation.
201 @[EROFS, EACCES, EPERM]@
202 \item @UnsatisfiedConstraints@
203 Implementation-dependent constraints are not satisfied.
205 \item @InappropriateType@
206 The operand refers to an existing directory.
212 rc <- _ccall_ removeFile path
216 constructErrorAndFail "removeFile"
219 @renameDirectory old@ {\em new} changes the name of an existing
220 directory from {\em old} to {\em new}. If the {\em new} directory
221 already exists, it is atomically replaced by the {\em old} directory.
222 If the {\em new} directory is neither the {\em old} directory nor an
223 alias of the {\em old} directory, it is removed as if by
224 $removeDirectory$. A conformant implementation need not support
225 renaming directories in all situations (e.g. renaming to an existing
226 directory, or across different physical devices), but the constraints
229 The operation may fail with:
231 \item @HardwareFault@
232 A physical I/O error has occurred.
234 \item @InvalidArgument@
235 Either operand is not a valid directory name.
236 @[ENAMETOOLONG, ELOOP]@
237 \item @isDoesNotExistError@ / @NoSuchThing@
238 The original directory does not exist, or there is no path to the target.
240 \item @isPermissionError@ / @PermissionDenied@
241 The process has insufficient privileges to perform the operation.
242 @[EROFS, EACCES, EPERM]@
243 \item @ResourceExhausted@
244 Insufficient resources are available to perform the operation.
245 @[EDQUOT, ENOSPC, ENOMEM, EMLINK]@
246 \item @UnsatisfiedConstraints@
247 Implementation-dependent constraints are not satisfied.
248 @[EBUSY, ENOTEMPTY, EEXIST]@
249 \item @UnsupportedOperation@
250 The implementation does not support renaming in this situation.
252 \item @InappropriateType@
253 Either path refers to an existing non-directory object.
258 renameDirectory opath npath = do
259 rc <- _ccall_ renameDirectory opath npath
263 constructErrorAndFail "renameDirectory"
266 @renameFile old@ {\em new} changes the name of an existing file system
267 object from {\em old} to {\em new}. If the {\em new} object already
268 exists, it is atomically replaced by the {\em old} object. Neither
269 path may refer to an existing directory. A conformant implementation
270 need not support renaming files in all situations (e.g. renaming
271 across different physical devices), but the constraints must be
274 The operation may fail with:
276 \item @HardwareFault@
277 A physical I/O error has occurred.
279 \item @InvalidArgument@
280 Either operand is not a valid file name.
281 @[ENAMETOOLONG, ELOOP]@
282 \item @isDoesNotExistError@ / @NoSuchThing@
283 The original file does not exist, or there is no path to the target.
285 \item @isPermissionError@ / @PermissionDenied@
286 The process has insufficient privileges to perform the operation.
287 @[EROFS, EACCES, EPERM]@
288 \item @ResourceExhausted@
289 Insufficient resources are available to perform the operation.
290 @[EDQUOT, ENOSPC, ENOMEM, EMLINK]@
291 \item @UnsatisfiedConstraints@
292 Implementation-dependent constraints are not satisfied.
294 \item @UnsupportedOperation@
295 The implementation does not support renaming in this situation.
297 \item @InappropriateType@
298 Either path refers to an existing directory.
299 @[ENOTDIR, EISDIR, EINVAL, EEXIST, ENOTEMPTY]@
303 renameFile opath npath = do
304 rc <- _ccall_ renameFile opath npath
308 constructErrorAndFail "renameFile"
311 @getDirectoryContents dir@ returns a list of {\em all} entries
314 The operation may fail with:
316 \item @HardwareFault@
317 A physical I/O error has occurred.
319 \item @InvalidArgument@
320 The operand is not a valid directory name.
321 @[ENAMETOOLONG, ELOOP]@
322 \item @isDoesNotExistError@ / @NoSuchThing@
323 The directory does not exist.
325 \item @isPermissionError@ / @PermissionDenied@
326 The process has insufficient privileges to perform the operation.
328 \item @ResourceExhausted@
329 Insufficient resources are available to perform the operation.
331 \item @InappropriateType@
332 The path refers to an existing non-directory object.
337 --getDirectoryContents :: FilePath -> IO [FilePath]
338 getDirectoryContents path = do
339 dir <- _ccall_ openDir__ path
341 then constructErrorAndFail "getDirectoryContents"
344 loop :: Addr -> IO [String]
346 dirent_ptr <- _ccall_ readDir__ dir
347 if (dirent_ptr::Addr) == ``NULL''
351 str <- _casm_ `` %r=(char*)((struct dirent*)%0)->d_name; '' dirent_ptr
352 -- not using the unpackCString function here, since we have to force
353 -- the unmarshalling of the directory entry right here as subsequent
354 -- calls to readdir() may overwrite it.
355 len <- _ccall_ strlen str
356 entry <- stToIO (unpackNBytesST str len)
358 return (entry:entries)
361 If the operating system has a notion of current directories,
362 @getCurrentDirectory@ returns an absolute path to the
363 current directory of the calling process.
365 The operation may fail with:
367 \item @HardwareFault@
368 A physical I/O error has occurred.
370 \item @isDoesNotExistError@ / @NoSuchThing@
371 There is no path referring to the current directory.
372 @[EPERM, ENOENT, ESTALE...]@
373 \item @isPermissionError@ / @PermissionDenied@
374 The process has insufficient privileges to perform the operation.
376 \item @ResourceExhausted@
377 Insufficient resources are available to perform the operation.
378 \item @UnsupportedOperation@
379 The operating system has no notion of current directory.
383 getCurrentDirectory = do
384 str <- _ccall_ getCurrentDirectory
387 len <- _ccall_ strlen str
388 pwd <- stToIO (unpackNBytesST str len)
392 constructErrorAndFail "getCurrentDirectory"
395 If the operating system has a notion of current directories,
396 @setCurrentDirectory dir@ changes the current
397 directory of the calling process to {\em dir}.
399 The operation may fail with:
401 \item @HardwareFault@
402 A physical I/O error has occurred.
404 \item @InvalidArgument@
405 The operand is not a valid directory name.
406 @[ENAMETOOLONG, ELOOP]@
407 \item @isDoesNotExistError@ / @NoSuchThing@
408 The directory does not exist.
410 \item @isPermissionError@ / @PermissionDenied@
411 The process has insufficient privileges to perform the operation.
413 \item @UnsupportedOperation@
414 The operating system has no notion of current directory, or the
415 current directory cannot be dynamically changed.
416 \item @InappropriateType@
417 The path refers to an existing non-directory object.
422 setCurrentDirectory path = do
423 rc <- _ccall_ setCurrentDirectory path
426 else constructErrorAndFail "setCurrentDirectory"
431 --doesFileExist :: FilePath -> IO Bool
432 doesFileExist name = do
433 rc <- _ccall_ access name (``F_OK''::Int)
436 --doesDirectoryExist :: FilePath -> IO Bool
437 doesDirectoryExist name =
438 (getFileStatus name >>= \ st -> return (isDirectory st))
440 (\ _ -> return False)
442 --getModificationTime :: FilePath -> IO ClockTime
443 getModificationTime name =
444 getFileStatus name >>= \ st ->
447 --getPermissions :: FilePath -> IO Permissions
448 getPermissions name =
449 getFileStatus name >>= \ st ->
452 isect v = intersectFileMode v fm == v
456 readable = isect ownerReadMode,
457 writeable = isect ownerWriteMode,
458 executable = not (isDirectory st) && isect ownerExecuteMode,
459 searchable = not (isRegularFile st) && isect ownerExecuteMode
463 --setPermissions :: FilePath -> Permissions -> IO ()
464 setPermissions name (Permissions r w e s) = do
466 read# = case (if r then ownerReadMode else ``0'') of { W# x# -> x# }
467 write# = case (if w then ownerWriteMode else ``0'') of { W# x# -> x# }
468 exec# = case (if e || s then ownerExecuteMode else ``0'') of { W# x# -> x# }
470 mode = I# (word2Int# (read# `or#` write# `or#` exec#))
472 rc <- _ccall_ chmod name mode
475 else fail (IOError Nothing SystemError "Directory.setPermissions")
480 (Sigh)..copied from Posix.Files to avoid dep. on posix library
483 type FileStatus = ByteArray Int
485 getFileStatus :: FilePath -> IO FileStatus
486 getFileStatus name = do
487 bytes <- stToIO (newCharArray (0,``sizeof(struct stat)''))
488 rc <- _casm_ ``%r = stat(%0,(struct stat *)%1);'' name bytes
490 then stToIO (unsafeFreezeByteArray bytes)
491 else fail (IOError Nothing SystemError "Directory.getFileStatus")
493 modificationTime :: FileStatus -> IO ClockTime
494 modificationTime stat = do
496 _casm_ ``((unsigned long *)%1)[0] = ((struct stat *)%0)->st_mtime;'' stat i1
497 secs <- cvtUnsigned i1
500 malloc1 = IO $ \ s# ->
501 case newIntArray# 1# s# of
502 StateAndMutableByteArray# s2# barr# ->
503 IOok s2# (MutableByteArray bnds barr#)
506 -- The C routine fills in an unsigned word. We don't have `unsigned2Integer#,'
507 -- so we freeze the data bits and use them for an MP_INT structure. Note that
508 -- zero is still handled specially, although (J# 1# 1# (ptr to 0#)) is probably
509 -- acceptable to gmp.
511 cvtUnsigned (MutableByteArray _ arr#) = IO $ \ s# ->
512 case readIntArray# arr# 0# s# of
513 StateAndInt# s2# r# ->
517 case unsafeFreezeByteArray# arr# s2# of
518 StateAndByteArray# s3# frozen# ->
519 IOok s3# (J# 1# 1# frozen#)
521 isDirectory :: FileStatus -> Bool
522 isDirectory stat = unsafePerformIO $ do
523 rc <- _casm_ ``%r = S_ISDIR(((struct stat *)%0)->st_mode);'' stat
526 isRegularFile :: FileStatus -> Bool
527 isRegularFile stat = unsafePerformIO $ do
528 rc <- _casm_ ``%r = S_ISREG(((struct stat *)%0)->st_mode);'' stat
534 ownerReadMode :: FileMode
535 ownerReadMode = ``S_IRUSR''
537 ownerWriteMode :: FileMode
538 ownerWriteMode = ``S_IWUSR''
540 ownerExecuteMode :: FileMode
541 ownerExecuteMode = ``S_IXUSR''
543 intersectFileMode :: FileMode -> FileMode -> FileMode
544 intersectFileMode (W# m1#) (W# m2#) = W# (m1# `and#` m2#)
546 fileMode :: FileStatus -> FileMode
547 fileMode stat = unsafePerformIO (
548 _casm_ ``%r = ((struct stat *)%0)->st_mode;'' stat)