How To Obtain the Owner of a File on Windows NT

This article was previously published under Q218965
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SUMMARY
Retrieving the owner of a file requires obtaining the security descriptor for the file, then using the security descriptor to get a pointer to the owner's Security Identifier (SID). Finally, you use the owner's SID to obtain the owner and domain name of the file.

This article provides a Visual Basic sample code that obtains the owner of a file on Microsoft Windows NT.
MORE INFORMATION
The following sample code retrieves the owner of the file notepad.exe, which is located in the default Windows folder.

NOTE: If the file is on an NTFS partition, this code returns the assigned owner of the file, but if it is on a FAT partition, the owner will be "Everyone".
  1. Start a new Visual Basic Standard EXE project. Form1 is created by default.
  2. Place a command button (Command1) on Form1.
  3. Paste the following code into the General Declarations section of Form1:
       Option Explicit   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 GetSecurityDescriptorOwner Lib "advapi32.dll" _      (pSecurityDescriptor As Any, _      pOwner As Long, _      lpbOwnerDefaulted 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 GetWindowsDirectory Lib "kernel32" _      Alias "GetWindowsDirectoryA" ( _      ByVal lpBuffer As String, _      ByVal nSize As Long) As Long   Private Const OWNER_SECURITY_INFORMATION = &H1   Private Const ERROR_INSUFFICIENT_BUFFER = 122&   Private Const MAX_PATH = 255   Sub Command1_Click()      Dim szfilename As String   ' File name to retrieve the owner for      Dim bSuccess As Long       ' Status variable      Dim sizeSD As Long         ' Buffer size to store Owner's SID      Dim pOwner As Long         ' Pointer to the Owner's SID      Dim name As String         ' Name of the file owner      Dim domain_name As String  ' Name of the first domain for the owner      Dim name_len As Long       ' Required length for the owner name      Dim domain_len As Long     ' Required length for the domain name      Dim sdBuf() As Byte        ' Buffer for Security Descriptor      Dim nLength As Long        ' Length of the Windows Directory      Dim deUse As Long          ' Pointer to a SID_NAME_USE enumerated                                  ' type indicating the type of the account    ' Initialize some required variables.      bSuccess = 0      name = ""      domain_name = ""      name_len = 0      domain_len = 0      pOwner = 0      szfilename = Space(MAX_PATH)   ' Obtain the path to the Windows Directory and use the notepad.exe file   ' as it should be on the system.   nLength = GetWindowsDirectory(szfilename, Len(szfilename))   If nLength = 0 Then     MsgBox "Unable to Obtain the Windows Directory"   End If   szfilename = Left$(szfilename, nLength) & "\notepad.exe"   ' Call GetFileSecurity the first time to obtain the size of the   ' buffer required for the Security Descriptor.   bSuccess = GetFileSecurity( _           szfilename, _           OWNER_SECURITY_INFORMATION, _           0, _           0&, _           sizeSD)   If (bSuccess = 0) And _      (Err.LastDllError <> ERROR_INSUFFICIENT_BUFFER) Then         MsgBox "GetLastError returned  : " & Err.LastDllError   End If   ' Create a buffer of the required size and call GetFileSecurity again.      ReDim sdBuf(0 To sizeSD - 1) As Byte   ' Fill the buffer with the security descriptor of the object specified   ' by the szfilename parameter. The calling process must have the right   ' to view the specified aspects of the object's security status.   bSuccess = GetFileSecurity( _           szfilename, _           OWNER_SECURITY_INFORMATION, _           sdBuf(0), _           sizeSD, _           sizeSD)   If (bSuccess <> 0) Then   ' Obtain the owner's SID from the Security Descriptor.   '      bSuccess = GetSecurityDescriptorOwner(sdBuf(0), pOwner, 0&)      If (bSuccess = 0) Then          MsgBox "GetLastError returned : " & Err.LastDllError      End If   ' Retrieve the name of the account and the name of the first   ' domain on which this SID is found.  Passes in the Owner's SID   ' obtained previously.  Call LookupAccountSid twice, the first time   ' to obtain the required size of the owner and domain names.      bSuccess = LookupAccountSid(vbNullString, pOwner, name, name_len, _                                  domain_name, domain_len, deUse)      If (bSuccess = 0) And _         (Err.LastDllError <> ERROR_INSUFFICIENT_BUFFER) Then         MsgBox "GetLastError returned : " & Err.LastDllError      End If   '  Allocate the required space in the name and domain_name string   '  variables. Allocate 1 byte less to avoid the appended NULL character.   '      name = Space(name_len - 1)      domain_name = Space(domain_len - 1)   '  Call LookupAccountSid again to actually fill in the name of the owner   '  and the first domain.   '      bSuccess = LookupAccountSid(vbNullString, pOwner, name, name_len, _                                  domain_name, domain_len, deUse)      If bSuccess = 0 Then          MsgBox "GetLastError returned : " & Err.LastDllError      End If      MsgBox "The Owner of " & szfilename & " is " & name      End If   End Sub					
  4. Press F5 to run the application and then click Command1 to display the owner of the file.
Properties

Article ID: 218965 - Last Review: 12/05/2015 13:04:35 - Revision: 3.2

Microsoft Visual Basic 5.0 Learning Edition, Microsoft Visual Basic 6.0 Learning Edition, Microsoft Visual Basic 5.0 Professional Edition, Microsoft Visual Basic 6.0 Professional Edition, Microsoft Visual Basic 5.0 Enterprise Edition, Microsoft Visual Basic 6.0 Enterprise Edition, Microsoft Visual Basic 4.0 Standard Edition, Microsoft Visual Basic 4.0 Professional Edition, Microsoft Visual Basic 4.0 32-Bit Enterprise Edition, Microsoft Windows NT 4.0, Microsoft Windows NT 3.51 Service Pack 5, Microsoft Windows NT 4.0, Microsoft Windows 2000 Standard Edition

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