1 | #Region "Microsoft.VisualBasic::a0263259f674405a4fedec9c4e65ce60, Microsoft.VisualBasic.Core\Extensions\IO\SymLinker\JunctionPoint.vb" |
2 | |
3 | ' Author: |
4 | ' |
5 | ' asuka (amethyst.asuka@gcmodeller.org) |
6 | ' xie (genetics@smrucc.org) |
7 | ' xieguigang (xie.guigang@live.com) |
8 | ' |
9 | ' Copyright (c) 2018 GPL3 Licensed |
10 | ' |
11 | ' |
12 | ' GNU GENERAL PUBLIC LICENSE (GPL3) |
13 | ' |
14 | ' |
15 | ' This program is free software: you can redistribute it and/or modify |
16 | ' it under the terms of the GNU General Public License as published by |
17 | ' the Free Software Foundation, either version 3 of the License, or |
18 | ' (at your option) any later version. |
19 | ' |
20 | ' This program is distributed in the hope that it will be useful, |
21 | ' but WITHOUT ANY WARRANTY; without even the implied warranty of |
22 | ' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
23 | ' GNU General Public License for more details. |
24 | ' |
25 | ' You should have received a copy of the GNU General Public License |
26 | ' along with this program. If not, see <http://www.gnu.org/licenses/>. |
27 | |
28 | |
29 | |
30 | ' /********************************************************************************/ |
31 | |
32 | ' Summaries: |
33 | |
34 | ' Module JunctionPoint |
35 | ' |
36 | ' |
37 | ' Enum EFileAccess |
38 | ' |
39 | ' |
40 | ' |
41 | ' |
42 | ' Enum EFileShare |
43 | ' |
44 | ' |
45 | ' |
46 | ' |
47 | ' |
48 | ' |
49 | ' Enum ECreationDisposition |
50 | ' |
51 | ' |
52 | ' |
53 | ' |
54 | ' |
55 | ' |
56 | ' Enum EFileAttributes |
57 | ' |
58 | ' |
59 | ' |
60 | ' |
61 | ' |
62 | ' |
63 | ' Structure REPARSE_DATA_BUFFER |
64 | ' |
65 | ' |
66 | ' |
67 | ' |
68 | ' |
69 | ' Function: CreateFile, DeviceIoControl, Exists, GetTarget, InternalGetTarget |
70 | ' OpenReparsePoint |
71 | ' |
72 | ' Sub: Create, Delete, ThrowLastWin32Error |
73 | ' |
74 | ' |
75 | ' /********************************************************************************/ |
76 | |
77 | #End Region |
78 | |
79 | Imports Microsoft.Win32.SafeHandles |
80 | Imports System.IO |
81 | Imports System.Runtime.InteropServices |
82 | Imports System.Text |
83 | |
84 | Namespace FileIO.SymLinker |
85 | |
86 | ''' <summary> |
87 | ''' Provides access to NTFS junction points in .Net. |
88 | ''' </summary> |
89 | Public Module JunctionPoint |
90 | |
91 | ''' <summary> |
92 | ''' The file or directory is not a reparse point. |
93 | ''' </summary> |
94 | Private Const ERROR_NOT_A_REPARSE_POINT As Integer = 4390 |
95 | |
96 | ''' <summary> |
97 | ''' The reparse point attribute cannot be set because it conflicts with an existing attribute. |
98 | ''' </summary> |
99 | Private Const ERROR_REPARSE_ATTRIBUTE_CONFLICT As Integer = 4391 |
100 | |
101 | ''' <summary> |
102 | ''' The data present in the reparse point buffer is invalid. |
103 | ''' </summary> |
104 | Private Const ERROR_INVALID_REPARSE_DATA As Integer = 4392 |
105 | |
106 | ''' <summary> |
107 | ''' The tag present in the reparse point buffer is invalid. |
108 | ''' </summary> |
109 | Private Const ERROR_REPARSE_TAG_INVALID As Integer = 4393 |
110 | |
111 | ''' <summary> |
112 | ''' There is a mismatch between the tag specified in the request and the tag present in the reparse point. |
113 | ''' </summary> |
114 | Private Const ERROR_REPARSE_TAG_MISMATCH As Integer = 4394 |
115 | |
116 | ''' <summary> |
117 | ''' Command to set the reparse point data block. |
118 | ''' </summary> |
119 | Private Const FSCTL_SET_REPARSE_POINT As Integer = &H900A4 |
120 | |
121 | ''' <summary> |
122 | ''' Command to get the reparse point data block. |
123 | ''' </summary> |
124 | Private Const FSCTL_GET_REPARSE_POINT As Integer = &H900A8 |
125 | |
126 | ''' <summary> |
127 | ''' Command to delete the reparse point data base. |
128 | ''' </summary> |
129 | Private Const FSCTL_DELETE_REPARSE_POINT As Integer = &H900AC |
130 | |
131 | ''' <summary> |
132 | ''' Reparse point tag used to identify mount points and junction points. |
133 | ''' </summary> |
134 | Private Const IO_REPARSE_TAG_MOUNT_POINT As UInteger = &HA0000003UI |
135 | |
136 | ''' <summary> |
137 | ''' This prefix indicates to NTFS that the path is to be treated as a non-interpreted |
138 | ''' path in the virtual file system. |
139 | ''' </summary> |
140 | Private Const NonInterpretedPathPrefix As String = "\??\" |
141 | |
142 | <Flags> |
143 | Private Enum EFileAccess As UInteger |
144 | GenericRead = &H80000000UI |
145 | GenericWrite = &H40000000 |
146 | GenericExecute = &H20000000 |
147 | GenericAll = &H10000000 |
148 | End Enum |
149 | |
150 | <Flags> |
151 | Private Enum EFileShare As UInteger |
152 | None = &H0 |
153 | Read = &H1 |
154 | Write = &H2 |
155 | Delete = &H4 |
156 | End Enum |
157 | |
158 | Private Enum ECreationDisposition As UInteger |
159 | [New] = 1 |
160 | CreateAlways = 2 |
161 | OpenExisting = 3 |
162 | OpenAlways = 4 |
163 | TruncateExisting = 5 |
164 | End Enum |
165 | |
166 | <Flags> |
167 | Private Enum EFileAttributes As UInteger |
168 | [Readonly] = &H1 |
169 | Hidden = &H2 |
170 | System = &H4 |
171 | Directory = &H10 |
172 | Archive = &H20 |
173 | Device = &H40 |
174 | Normal = &H80 |
175 | Temporary = &H100 |
176 | SparseFile = &H200 |
177 | ReparsePoint = &H400 |
178 | Compressed = &H800 |
179 | Offline = &H1000 |
180 | NotContentIndexed = &H2000 |
181 | Encrypted = &H4000 |
182 | Write_Through = &H80000000UI |
183 | Overlapped = &H40000000 |
184 | NoBuffering = &H20000000 |
185 | RandomAccess = &H10000000 |
186 | SequentialScan = &H8000000 |
187 | DeleteOnClose = &H4000000 |
188 | BackupSemantics = &H2000000 |
189 | PosixSemantics = &H1000000 |
190 | OpenReparsePoint = &H200000 |
191 | OpenNoRecall = &H100000 |
192 | FirstPipeInstance = &H80000 |
193 | End Enum |
194 | |
195 | <StructLayout(LayoutKind.Sequential)> |
196 | Private Structure REPARSE_DATA_BUFFER |
197 | ''' <summary> |
198 | ''' Reparse point tag. Must be a Microsoft reparse point tag. |
199 | ''' </summary> |
200 | Public ReparseTag As UInteger |
201 | |
202 | ''' <summary> |
203 | ''' Size, in bytes, of the data after the Reserved member. This can be calculated by: |
204 | ''' (4 * sizeof(ushort)) + SubstituteNameLength + PrintNameLength + |
205 | ''' (namesAreNullTerminated ? 2 * sizeof(char) : 0); |
206 | ''' </summary> |
207 | Public ReparseDataLength As UShort |
208 | |
209 | ''' <summary> |
210 | ''' Reserved; do not use. |
211 | ''' </summary> |
212 | Public Reserved As UShort |
213 | |
214 | ''' <summary> |
215 | ''' Offset, in bytes, of the substitute name string in the PathBuffer array. |
216 | ''' </summary> |
217 | Public SubstituteNameOffset As UShort |
218 | |
219 | ''' <summary> |
220 | ''' Length, in bytes, of the substitute name string. If this string is null-terminated, |
221 | ''' SubstituteNameLength does not include space for the null character. |
222 | ''' </summary> |
223 | Public SubstituteNameLength As UShort |
224 | |
225 | ''' <summary> |
226 | ''' Offset, in bytes, of the print name string in the PathBuffer array. |
227 | ''' </summary> |
228 | Public PrintNameOffset As UShort |
229 | |
230 | ''' <summary> |
231 | ''' Length, in bytes, of the print name string. If this string is null-terminated, |
232 | ''' PrintNameLength does not include space for the null character. |
233 | ''' </summary> |
234 | Public PrintNameLength As UShort |
235 | |
236 | ''' <summary> |
237 | ''' A buffer containing the unicode-encoded path string. The path string contains |
238 | ''' the substitute name string and print name string. |
239 | ''' </summary> |
240 | <MarshalAs(UnmanagedType.ByValArray, SizeConst:=&H3FF0)> |
241 | Public PathBuffer As Byte() |
242 | End Structure |
243 | |
244 | <DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> |
245 | Private Function DeviceIoControl(hDevice As IntPtr, |
246 | dwIoControlCode As UInteger, |
247 | InBuffer As IntPtr, |
248 | nInBufferSize As Integer, |
249 | OutBuffer As IntPtr, |
250 | nOutBufferSize As Integer, |
251 | ByRef pBytesReturned As Integer, |
252 | lpOverlapped As IntPtr) As Boolean |
253 | End Function |
254 | |
255 | <DllImport("kernel32.dll", SetLastError:=True)> |
256 | Private Function CreateFile(lpFileName As String, |
257 | dwDesiredAccess As EFileAccess, |
258 | dwShareMode As EFileShare, |
259 | lpSecurityAttributes As IntPtr, |
260 | dwCreationDisposition As ECreationDisposition, |
261 | dwFlagsAndAttributes As EFileAttributes, |
262 | hTemplateFile As IntPtr) As IntPtr |
263 | End Function |
264 | |
265 | ''' <summary> |
266 | ''' Creates a junction point from the specified directory to the specified target directory. |
267 | ''' </summary> |
268 | ''' <remarks> |
269 | ''' Only works on NTFS. |
270 | ''' </remarks> |
271 | ''' <param name="junctionPoint">The junction point path</param> |
272 | ''' <param name="targetDir">The target directory</param> |
273 | ''' <param name="overwrite">If true overwrites an existing reparse point or empty directory</param> |
274 | ''' <exception cref="IOException">Thrown when the junction point could not be created or when |
275 | ''' an existing directory was found and <paramref name="overwrite" /> if false</exception> |
276 | Public Sub Create(junctionPoint As String, targetDir As String, overwrite As Boolean) |
277 | targetDir = Path.GetFullPath(targetDir) |
278 | |
279 | If Not Directory.Exists(targetDir) Then |
280 | Throw New IOException("Target path does not exist or is not a directory.") |
281 | End If |
282 | |
283 | If Directory.Exists(junctionPoint) Then |
284 | If Not overwrite Then |
285 | Throw New IOException("Directory already exists and overwrite parameter is false.") |
286 | End If |
287 | Else |
288 | Directory.CreateDirectory(junctionPoint) |
289 | End If |
290 | |
291 | Using handle As SafeFileHandle = OpenReparsePoint(junctionPoint, EFileAccess.GenericWrite) |
292 | Dim targetDirBytes As Byte() = Encoding.Unicode.GetBytes(NonInterpretedPathPrefix & Path.GetFullPath(targetDir)) |
293 | |
294 | Dim reparseDataBuffer As New REPARSE_DATA_BUFFER() |
295 | |
296 | reparseDataBuffer.ReparseTag = IO_REPARSE_TAG_MOUNT_POINT |
297 | reparseDataBuffer.ReparseDataLength = CUShort(targetDirBytes.Length + 12) |
298 | reparseDataBuffer.SubstituteNameOffset = 0 |
299 | reparseDataBuffer.SubstituteNameLength = CUShort(targetDirBytes.Length) |
300 | reparseDataBuffer.PrintNameOffset = CUShort(targetDirBytes.Length + 2) |
301 | reparseDataBuffer.PrintNameLength = 0 |
302 | reparseDataBuffer.PathBuffer = New Byte(16367) {} |
303 | Array.Copy(targetDirBytes, reparseDataBuffer.PathBuffer, targetDirBytes.Length) |
304 | |
305 | Dim inBufferSize As Integer = Marshal.SizeOf(reparseDataBuffer) |
306 | Dim inBuffer As IntPtr = Marshal.AllocHGlobal(inBufferSize) |
307 | |
308 | Try |
309 | Marshal.StructureToPtr(reparseDataBuffer, inBuffer, False) |
310 | |
311 | Dim bytesReturned As Integer |
312 | Dim result As Boolean = DeviceIoControl(handle.DangerousGetHandle(), FSCTL_SET_REPARSE_POINT, inBuffer, targetDirBytes.Length + 20, IntPtr.Zero, 0, |
313 | bytesReturned, IntPtr.Zero) |
314 | |
315 | If Not result Then |
316 | ThrowLastWin32Error("Unable to create junction point.") |
317 | End If |
318 | Finally |
319 | Marshal.FreeHGlobal(inBuffer) |
320 | End Try |
321 | End Using |
322 | End Sub |
323 | |
324 | ''' <summary> |
325 | ''' Deletes a junction point at the specified source directory along with the directory itself. |
326 | ''' Does nothing if the junction point does not exist. |
327 | ''' </summary> |
328 | ''' <remarks> |
329 | ''' Only works on NTFS. |
330 | ''' </remarks> |
331 | ''' <param name="junctionPoint">The junction point path</param> |
332 | Public Sub Delete(junctionPoint As String) |
333 | If Not Directory.Exists(junctionPoint) Then |
334 | If File.Exists(junctionPoint) Then |
335 | Throw New IOException("Path is not a junction point.") |
336 | End If |
337 | |
338 | Return |
339 | End If |
340 | |
341 | Using handle As SafeFileHandle = OpenReparsePoint(junctionPoint, EFileAccess.GenericWrite) |
342 | Dim reparseDataBuffer As New REPARSE_DATA_BUFFER() |
343 | |
344 | reparseDataBuffer.ReparseTag = IO_REPARSE_TAG_MOUNT_POINT |
345 | reparseDataBuffer.ReparseDataLength = 0 |
346 | reparseDataBuffer.PathBuffer = New Byte(16367) {} |
347 | |
348 | Dim inBufferSize As Integer = Marshal.SizeOf(reparseDataBuffer) |
349 | Dim inBuffer As IntPtr = Marshal.AllocHGlobal(inBufferSize) |
350 | Try |
351 | Marshal.StructureToPtr(reparseDataBuffer, inBuffer, False) |
352 | |
353 | Dim bytesReturned As Integer |
354 | Dim result As Boolean = DeviceIoControl(handle.DangerousGetHandle(), FSCTL_DELETE_REPARSE_POINT, inBuffer, 8, IntPtr.Zero, 0, |
355 | bytesReturned, IntPtr.Zero) |
356 | |
357 | If Not result Then |
358 | ThrowLastWin32Error("Unable to delete junction point.") |
359 | End If |
360 | Finally |
361 | Marshal.FreeHGlobal(inBuffer) |
362 | End Try |
363 | |
364 | Try |
365 | Directory.Delete(junctionPoint) |
366 | Catch ex As IOException |
367 | Throw New IOException("Unable to delete junction point.", ex) |
368 | End Try |
369 | End Using |
370 | End Sub |
371 | |
372 | ''' <summary> |
373 | ''' Determines whether the specified path exists and refers to a junction point. |
374 | ''' </summary> |
375 | ''' <param name="path">The junction point path</param> |
376 | ''' <returns>True if the specified path represents a junction point</returns> |
377 | ''' <exception cref="IOException">Thrown if the specified path is invalid |
378 | ''' or some other error occurs</exception> |
379 | Public Function Exists(path As String) As Boolean |
380 | If Not Directory.Exists(path) Then |
381 | Return False |
382 | End If |
383 | |
384 | Using handle As SafeFileHandle = OpenReparsePoint(path, EFileAccess.GenericRead) |
385 | Dim target As String = InternalGetTarget(handle) |
386 | Return target IsNot Nothing |
387 | End Using |
388 | End Function |
389 | |
390 | ''' <summary> |
391 | ''' Gets the target of the specified junction point. |
392 | ''' </summary> |
393 | ''' <remarks> |
394 | ''' Only works on NTFS. |
395 | ''' </remarks> |
396 | ''' <param name="junctionPoint">The junction point path</param> |
397 | ''' <returns>The target of the junction point</returns> |
398 | ''' <exception cref="IOException">Thrown when the specified path does not |
399 | ''' exist, is invalid, is not a junction point, or some other error occurs</exception> |
400 | Public Function GetTarget(junctionPoint As String) As String |
401 | Using handle As SafeFileHandle = OpenReparsePoint(junctionPoint, EFileAccess.GenericRead) |
402 | Dim target As String = InternalGetTarget(handle) |
403 | If target Is Nothing Then |
404 | Throw New IOException("Path is not a junction point.") |
405 | End If |
406 | |
407 | Return target |
408 | End Using |
409 | End Function |
410 | |
411 | Private Function InternalGetTarget(handle As SafeFileHandle) As String |
412 | Dim outBufferSize As Integer = Marshal.SizeOf(GetType(REPARSE_DATA_BUFFER)) |
413 | Dim outBuffer As IntPtr = Marshal.AllocHGlobal(outBufferSize) |
414 | |
415 | Try |
416 | Dim bytesReturned As Integer |
417 | Dim result As Boolean = DeviceIoControl(handle.DangerousGetHandle(), FSCTL_GET_REPARSE_POINT, IntPtr.Zero, 0, outBuffer, outBufferSize, |
418 | bytesReturned, IntPtr.Zero) |
419 | |
420 | If Not result Then |
421 | Dim [error] As Integer = Marshal.GetLastWin32Error() |
422 | If [error] = ERROR_NOT_A_REPARSE_POINT Then |
423 | Return Nothing |
424 | End If |
425 | |
426 | ThrowLastWin32Error("Unable to get information about junction point.") |
427 | End If |
428 | |
429 | Dim reparseDataBuffer As REPARSE_DATA_BUFFER = CType(Marshal.PtrToStructure(outBuffer, GetType(REPARSE_DATA_BUFFER)), REPARSE_DATA_BUFFER) |
430 | |
431 | If reparseDataBuffer.ReparseTag <> IO_REPARSE_TAG_MOUNT_POINT Then |
432 | Return Nothing |
433 | End If |
434 | |
435 | Dim targetDir As String = Encoding.Unicode.GetString(reparseDataBuffer.PathBuffer, reparseDataBuffer.SubstituteNameOffset, reparseDataBuffer.SubstituteNameLength) |
436 | |
437 | If targetDir.StartsWith(NonInterpretedPathPrefix) Then |
438 | targetDir = targetDir.Substring(NonInterpretedPathPrefix.Length) |
439 | End If |
440 | |
441 | Return targetDir |
442 | Finally |
443 | Marshal.FreeHGlobal(outBuffer) |
444 | End Try |
445 | End Function |
446 | |
447 | Private Function OpenReparsePoint(reparsePoint As String, accessMode As EFileAccess) As SafeFileHandle |
448 | Dim reparsePointHandle As New SafeFileHandle(CreateFile(reparsePoint, accessMode, EFileShare.Read Or EFileShare.Write Or EFileShare.Delete, IntPtr.Zero, ECreationDisposition.OpenExisting, EFileAttributes.BackupSemantics Or EFileAttributes.OpenReparsePoint, |
449 | IntPtr.Zero), True) |
450 | |
451 | If Marshal.GetLastWin32Error() <> 0 Then |
452 | ThrowLastWin32Error("Unable to open reparse point.") |
453 | End If |
454 | |
455 | Return reparsePointHandle |
456 | End Function |
457 | |
458 | Private Sub ThrowLastWin32Error(message As String) |
459 | Throw New IOException(message, Marshal.GetExceptionForHR(Marshal.GetHRForLastWin32Error())) |
460 | End Sub |
461 | End Module |
462 | End Namespace |