 GetFileSecurity, LookupAccountSid and
GetSecurityDescriptorOwner can be
combined to return the owner of a file or a folder on a local or remote
machine.
The illustration shows the result of calling the code below passing my
laptop name and a folder in the test user's My Documents folder on that machine.
Changing the code to add a filename to the passed path causes the
routine to return the owner of the file. To test this I
logged off test user and back on as my usual admin account, then I created a text file in the testuseraccount's My Documents folder. The code correctly returned
my admin account as being the owner of the file; requesting the owner of
the folder again returned the test user's account name.
Incidentally (at least on my workgroup setup), the code accurately
returned the correct info for both files and folders when no users were
logged on to the laptop (it was waiting at the "click name to begin"
screen (fast user switching was not enabled). |
Option Explicit
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Distribution: You can freely use this code in your own
' applications, but you may not reproduce
' or publish this code on any web site,
' online service, or distribute as source
' on any media without express permission.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Private Const OWNER_SECURITY_INFORMATION = &H1
Private Const ERROR_INSUFFICIENT_BUFFER = 122&
Private 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
Private Declare Function LookupAccountSid Lib "advapi32.dll" _
Alias "LookupAccountSidA" _
(ByVal lpSystemName As String, _
ByVal Sid As Long, _
ByVal name As String, _
cbName As Long, _
ByVal ReferencedDomainName As String, _
cbReferencedDomainName As Long, _
peUse As Long) As Long
Private Declare Function GetSecurityDescriptorOwner Lib "advapi32.dll" _
(pSecurityDescriptor As Any, _
pOwner As Long, _
lpbOwnerDefaulted As Long) As Long
Private Declare Function lstrlenW Lib "kernel32" _
(ByVal lpString As Long) As Long
Private Sub Form_Load()
With Command1
.Width = 2000
.Height = 345
.Caption = "Get Folder Owner"
End With
Text1.Text = ""
End Sub
Sub Command1_Click()
Text1.Text = GetFolderOwner("vbnetvaio", "c$\Documents and Settings\testuseraccount\My Documents")
'Text1.Text = GetFolderOwner("vbnetvaio", "c$\program files")
'Text1.Text = GetFolderOwner("", "c:\my documents")
'Text1.Text = GetFolderOwner("vbnetvaio", "c$\Documents and Settings\testuseraccount\My Documents\abc.txt")
End Sub
Private Function GetFolderOwner(ByVal sServer As String, ByVal sFolder As String) As String
Dim bSuccess As Long
Dim sizeSD As Long
Dim pOwner As Long
Dim sFolderOwner As String
Dim cbFolderOwner As Long
Dim sDomainName As String
Dim cbDomainName As Long
Dim sFullFolderName As String
Dim sdBuf() As Byte
Dim deUse As Long
'TODO: GetFileSecurity requires the full path
'to the folder. If a server was passed, this
'is included in the filename when the path
'is a UNC path. When the specified folder
'is a mapped drive the server is still
'required for LookupAccountSID, but is not
'required for GetFileSecurity. Tests for
'different strings passed should be accounted
'for in a production version of this code.
'To simplify the demo, we'll just do preliminary
'work with the strings to ensure the
'server name formatting is correct;
'if no server specified assume local machine
If Len(sServer) > 0 Then
sServer = QualifyServer(sServer)
sFullFolderName = QualifyPath(sServer) & sFolder
Else
sServer = vbNullString
sFullFolderName = sFolder
End If
'step 1: call GetFileSecurity to get
'the size of the buffer required
bSuccess = GetFileSecurity(sFullFolderName, _
OWNER_SECURITY_INFORMATION, _
0, 0&, sizeSD)
If (bSuccess = 0) And _
(Err.LastDllError = ERROR_INSUFFICIENT_BUFFER) Then
'step 2: create buffer of required
'size and call again
ReDim sdBuf(0 To sizeSD - 1) As Byte
bSuccess = GetFileSecurity(sFullFolderName, _
OWNER_SECURITY_INFORMATION, _
sdBuf(0), _
sizeSD, sizeSD)
If (bSuccess <> 0) Then
'step 3: obtain owner's SID from
'the security descriptor
If GetSecurityDescriptorOwner(sdBuf(0), pOwner, 0&) = 1 Then
'step 4: call LookupAccountSid twice to
'get the name of the account and the
'first domain on which this SID is found;
'the first call gets the correct buffer size,
'the second gets the data
bSuccess = LookupAccountSid(sServer, _
pOwner, _
sFolderOwner, _
cbFolderOwner, _
sDomainName, _
cbDomainName, _
deUse)
If (bSuccess = 0) And _
(Err.LastDllError = ERROR_INSUFFICIENT_BUFFER) Then
'fill buffers and call again
sFolderOwner = Space$(cbFolderOwner)
sDomainName = Space$(cbDomainName)
If LookupAccountSid(sServer, _
pOwner, _
sFolderOwner, _
cbFolderOwner, _
sDomainName, _
cbDomainName, _
deUse) = 1 Then
GetFolderOwner = TrimNull(sFolderOwner)
End If 'LookupAccountSid
End If 'bSuccess /3
End If 'GetSecurityDescriptorOwner
End If 'bSuccess /2
End If 'bSuccess /1
End Function
Private Function QualifyServer(ByVal sServer As String) As String
'if nullstring was passed, the
'API does not expect slashes in
'the server name
If Len(sServer) > 0 Then
'are already two slashes
'preceding the server name?
If Left$(sServer, 2) = "\\" Then
'return the passed string
QualifyServer = sServer
Else
'there aren't two, but is there one?
If Left$(sServer, 1) = "\" Then
'yes, so add one more
QualifyServer = "\" & sServer
Else
'the string needs both
QualifyServer = "\\" & sServer
End If 'Left$(sServer, 1) <> "\"
End If 'Left$(sServer, 2) = "\\"
Else
'empty string passed, so return it
QualifyServer = sServer
End If 'Len(sServer)
End Function
Private Function QualifyPath(sPath As String) As String
If Len(sPath) > 0 Then
If Right$(sPath, 1) <> "\" Then
QualifyPath = sPath & "\"
Else
QualifyPath = sPath
End If
Else
QualifyPath = ""
End If
End Function
Private Function TrimNull(startstr As String) As String
TrimNull = Left$(startstr, lstrlenW(StrPtr(startstr)))
End Function
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