VB取得磁盘文件夹或文件的security
来源:优易学  2011-12-10 20:36:18   【优易学:中国教育考试门户网】   资料下载   IT书店

  实现代码如下:
  Option Explicit
  Public Const MAXIMUM_ALLOWED As Long = &H2000000
  Public Const DELETE As Long = &H10000
  Public Const READ_CONTROL As Long = &H20000
  Public Const WRITE_DAC As Long = &H40000
  Public Const WRITE_OWNER As Long = &H80000
  Public Const SYNCHRONIZE As Long = &H100000
  Public Const STANDARD_RIGHTS_READ As Long = READ_CONTROL
  Public Const STANDARD_RIGHTS_WRITE As Long = READ_CONTROL
  Public Const STANDARD_RIGHTS_EXECUTE As Long = READ_CONTROL
  Public Const STANDARD_RIGHTS_REQUIRED As Long = &HF0000
  Public Const FILE_READ_DATA As Long = &H1
  Public Const FILE_LIST_DIRECTORY As Long = &H1
  Public Const FILE_ADD_FILE As Long = &H2
  Public Const FILE_WRITE_DATA As Long = &H2
  Public Const FILE_CREATE_PIPE_INSTANCE As Long = &H4
  Public Const FILE_ADD_SUBDIRECTORY As Long = &H4
  Public Const FILE_APPEND_DATA As Long = &H4
  Public Const FILE_READ_EA As Long = &H8
  Public Const FILE_READ_PROPERTIES As Long = FILE_READ_EA
  Public Const FILE_WRITE_EA As Long = &H10
  Public Const FILE_WRITE_PROPERTIES As Long = FILE_WRITE_EA
  Public Const FILE_EXECUTE As Long = &H20
  Public Const FILE_TRAVERSE As Long = &H20
  Public Const FILE_DELETE_CHILD As Long = &H40
  Public Const FILE_READ_ATTRIBUTES As Long = &H80
  Public Const FILE_WRITE_ATTRIBUTES As Long = &H100
  Public Const FILE_GENERIC_READ As Long = (STANDARD_RIGHTS_READ Or FILE_READ_DATA Or FILE_READ_ATTRIBUTES Or FILE_READ_EA Or FILE_EXECUTE Or STANDARD_RIGHTS_EXECUTE Or SYNCHRONIZE)
  Public Const FILE_GENERIC_READ As Long = (STANDARD_RIGHTS_READ Or FILE_READ_DATA Or FILE_READ_ATTRIBUTES Or FILE_READ_EA Or SYNCHRONIZE)
  Public Const FILE_GENERIC_EXECUTE As Long = (STANDARD_RIGHTS_EXECUTE Or FILE_READ_ATTRIBUTES Or FILE_EXECUTE Or SYNCHRONIZE)
  Public Const FILE_GENERIC_WRITE As Long = (STANDARD_RIGHTS_WRITE Or FILE_WRITE_DATA Or FILE_WRITE_ATTRIBUTES Or FILE_WRITE_EA Or FILE_APPEND_DATA Or SYNCHRONIZE)
  Public Const FILE_ALL_ACCESS As Long = (STANDARD_RIGHTS_REQUIRED Or SYNCHRONIZE Or &H1FF&)
  Public Const GENERIC_READ As Long = &H80000000
  Public Const GENERIC_WRITE As Long = &H40000000
  Public Const GENERIC_EXECUTE As Long = &H20000000
  Public Const GENERIC_ALL As Long = &H10000000
  ' Types, constants and functions to work with access rights
  Public Const OWNER_SECURITY_INFORMATION As Long = &H1
  Public Const GROUP_SECURITY_INFORMATION As Long = &H2
  Public Const DACL_SECURITY_INFORMATION As Long = &H4
  Public Const TOKEN_QUERY As Long = 8
  Public Const SecurityImpersonation As Integer = 3
  Public Const ANYSIZE_ARRAY = 1
  Public Const ACEListDirectory = 1
  Public Const ACEReadData = 1
  Public Const ACECreateFiles = 2
  Public Const ACEWriteData = 2
  Public Const ACECreateDirectories = 4
  Public Const ACEAppendData = 4
  Public Const ACEReadExtendedAttributes = 8
  Public Const ACEWriteExtendedAttributes = 16
  Public Const ACEExecuteFile = 32
  Public Const ACETraverse = 32
  Public Const ACEDeleteSubdirectoriesAndFiles = 64
  Public Const ACEReadAttributes = 128
  Public Const ACEWriteAttributes = 256
  'Public Const ACEWrite = 278
  Public Const ACEDelete = 65536
  Public Const ACEReadPermissions = 131072
  'Public Const ACERead = 131209
  'Public Const ACEReadAndExecute = 131241
  'Public Const ACEModify = 197055
  Public Const ACEChangePermissions = 262144
  Public Const ACETakeOwnership = 524288
  Public Const ACESynchronize = 1048576
  'Public Const ACEFullControl = 2032127
  Public Type GENERIC_MAPPING
  GenericRead As Long
  GenericWrite As Long
  GenericExecute As Long
  GenericAll As Long
  End Type
  Public Type LUID
  LowPart As Long
  HighPart As Long
  End Type

  Public Type LUID_AND_ATTRIBUTES
  pLuid As LUID
  Attributes As Long
  End Type
  Public Type PRIVILEGE_SET
  PrivilegeCount As Long
  Control As Long
  Privilege(ANYSIZE_ARRAY) As LUID_AND_ATTRIBUTES
  End Type
  Public Declare Function GetFileSecurity Lib "advapi32.dll" Alias "GetFileSecurityA" (ByVal lpFileName As String,ByVal RequestedInformation As Long, pSecurityDescriptor As Byte,ByVal nLength As Long, lpnLengthNeeded As Long) As Long
  Public Declare Function AccessCheck Lib "advapi32.dll" (pSecurityDescriptor As Byte, ByVal ClientToken As Long,ByVal DesiredAccess As Long, GenericMapping As GENERIC_MAPPING,PrivilegeSet As PRIVILEGE_SET, PrivilegeSetLength As Long, GrantedAccess As Long, Status As Long) As Long
  Public Declare Function ImpersonateSelf Lib "advapi32.dll" (ByVal ImpersonationLevel As Integer) As Long
  Public Declare Function RevertToSelf Lib "advapi32.dll" () As Long
  Public Declare Sub MapGenericMask Lib "advapi32.dll" (AccessMask As Long,GenericMapping As GENERIC_MAPPING)
  Public Declare Function OpenThreadToken Lib "advapi32.dll"(ByVal ThreadHandle As Long, ByVal DesiredAccess As Long,ByVal OpenAsSelf As Long, TokenHandle As Long) As Long
  Public Declare Function GetCurrentThread Lib "kernel32" () As Long
  Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
  Public Type OSVERSIONINFO
  dwOSVersionInfoSize As Long
  dwMajorVersion As Long
  dwMinorVersion As Long
  dwBuildNumber As Long
  dwPlatformId As Long
  szCSDVersion As String * 128
  End Type
  Public Const VER_PLATFORM_WIN32_NT As Long = 2
  Public Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" _
  (lpVersionInformation As OSVERSIONINFO) As Long
  Public Const FS_PERSISTENT_ACLS As Long = &H8
  Public Declare Function GetVolumeInformation Lib "kernel32" Alias "GetVolumeInformationA" (ByVal lpRootPathName As String,ByVal lpVolumeNameBuffer As String, ByVal nVolumeNameSize As Long,lpVolumeSerialNumber As Long, lpMaximumComponentLength As Long,lpFileSystemFlags As Long, ByVal lpFileSystemNameBuffer As String,ByVal nFileSystemNameSize As Long) As Long
  ’检查文件的访问权限
  Public Function CheckFileAccess(fileName As String, ByVal DesiredAccess As Long) As Long
  Dim r As Long, SecDesc() As Byte, SDSize As Long, hToken As Long
  Dim PrivSet As PRIVILEGE_SET, GenMap As GENERIC_MAPPING
  Dim Volume As String, FSFlags As Long
  If Not IsNT() Then
  CheckFileAccess = -1
  Exit Function
  End If
  If Left$(fileName, 2) = "\\" Then
  r = InStr(3, fileName, "\")
  If r = 0 Then
  Volume = fileName & "\"
  Else
  Volume = Left$(fileName, r)
  End If
  ElseIf Mid$(fileName, 2, 2) = ":\" Then
  Volume = Left$(fileName, 3)
  End If
  GetVolumeInformation Volume, vbNullString, 0, ByVal 0&, _
  ByVal 0&, FSFlags, vbNullString, 0
  If (FSFlags And FS_PERSISTENT_ACLS) = 0 Then
  CheckFileAccess = -1
  Exit Function
  End If
  GetFileSecurity fileName, OWNER_SECURITY_INFORMATION Or GROUP_SECURITY_INFORMATION Or DACL_SECURITY_INFORMATION, 0, 0, SDSize
  If Err.LastDllError <> 122 Then
  CheckFileAccess = -1 'Rights not supported. Returning -1.
  Exit Function
  End If
  If SDSize = 0 Then Exit Function
  ReDim SecDesc(1 To SDSize)
  If GetFileSecurity(fileName, OWNER_SECURITY_INFORMATION _
  Or GROUP_SECURITY_INFORMATION _
  Or DACL_SECURITY_INFORMATION, _
  SecDesc(1), SDSize, SDSize) = 0 Then
  Exit Function
  End If
  ImpersonateSelf SecurityImpersonation 'Adding Impersonation Token for thread
  OpenThreadToken GetCurrentThread(), TOKEN_QUERY, 0, hToken 'Opening of Token of current thread
  If hToken <> 0 Then
  GenMap.GenericRead = FILE_GENERIC_READ
  GenMap.GenericWrite = FILE_GENERIC_WRITE
  GenMap.GenericExecute = FILE_GENERIC_EXECUTE
  GenMap.GenericAll = FILE_ALL_ACCESS
  MapGenericMask DesiredAccess, GenMap
  AccessCheck SecDesc(1), hToken, DesiredAccess, GenMap, PrivSet, Len(PrivSet), CheckFileAccess, r
  CloseHandle hToken
  End If
  RevertToSelf
  End Function

责任编辑:小草

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