Who's Logged On?

[grandhigh]

On a NT Domain is there an API call That will tell me the NT username of the user logged on to a particular machine.

[chrisf]

Try

Declare Function GetUserName Lib"advapi32.dll" Alias "GetUserNameA"_
(ByVal lpBuffer As String, nSize As Long) As Long

[grandhigh]

Sorry but i can't seem to get this function to work got any examples of how it should be called?

[JoshT]

This was probably originally from one of the vb api sites.

Private Sub Command1_Click()
    ' Display the name of the user currently logged on.
    Dim username As String  ' receives name of the user
    Dim slength As Long  ' length of the string
    Dim retval As Long  ' return value
    
    ' Create room in the buffer to receive the returned string.
    username = Space(255)  ' room for 255 characters
    slength = 255  ' initialize the size of the string
    ' Get the user's name and display it.
    retval = GetUserName(username, slength)  ' slength is now the length of the returned string
    username = Left(username, slength - 1)  ' extract the returned info from the buffer
    ' (We subtracted one because we don't want the null character in the trimmed string.)
    Text1.Text = username
End Sub

[AKA]

Hi !

Can you get the domain name also ? I was thinking of using it as security in my program and I want to make sure that noone makes a accont on local machin with same name as in the domain and therefore get the domain users rights.

/AKA

[JoshT]

The GetUserNameEx API call gets more info, including the full username (DOMAIN\username), but it only works with Windows 2000.

[AKA]

I am using NT so I can not use the GetUserNameEx API. Any other good ideas.

/AKA

[Megatron]

Try the LookupAccountName() API function.

[AKA]

Hi !

I tried LookUpAccountName last week and never got it working. Do you have an example ? I am now trying to rewrite some C code using LookUpAccountSid. I think that I have got all parts working except the call to LookUpAccountSid.

Note, I dont include the API declarations in the code.

      Private Sub ShowUserName()

        Const TOKEN_QUERY = &H8
        Dim retVal As Long
        Dim tUser As TOKEN_USER
        
        Dim Leng As Long
        Dim LengNeeded As Long
        Dim strAccountName As String * 1000
        Dim strDomainName As String * 1000
        Dim lngAccountLength As Long
        Dim lngDomainLength As Long
        Dim lngSIDTypeReturned As Integer
        Dim hdlProcessHandle As Long
        Dim hdlToken As Long
        
        'Set the error code of the last thread to zero using the
        'SetLast Error function. Do this so that the GetLastError
        'function does not return a value other than zero for no
        'apparent reason.
        SetLastError 0

        'Use the GetCurrentProcess function to set the hdlProcessHandle
        'variable.
        hdlProcessHandle = GetCurrentProcess()

        If GetLastError <> 0 Then
           MsgBox "GetCurrentProcess error==" & GetLastError
        End If

        OpenProcessToken hdlProcessHandle, _
           (TOKEN_QUERY), hdlToken

        If GetLastError <> 0 Then
           MsgBox "OpenProcessToken error==" & GetLastError
        End If


        Leng = 1
        ReDim Token(0)
        ' this should fail, because the buffer is to small
        retVal = GetTokenInformation(hdlToken, TokenUser, Token(0), Leng, LengNeeded)
        If retVal = 0 Then
            Leng = LengNeeded
            ReDim Token(Leng - 1)
            ' now it should succeed
            retVal = GetTokenInformation(hdlToken, TokenUser, Token(0), Leng, LengNeeded)
            If retVal <> 0 Then
                ' copy the first 8 bytes to the TOKEN_USER structure.
                Call CopyMem(tUser, Token(0), Len(tUser))
                ' we have a pointer to the sid in the TOKEN_USER
                ' first check is the sid is valid
                retVal = IsValidSid(tUser.User.Sid)
                
                If retVal = 0 Then
                    MsgBox "Sid is not valid"
                End If
                            
                lngAccountLength = 1000
                lngDomainLength = 1000
                lngSIDTypeReturned = 1
                
                retVal = LookupAccountSid(vbNullChar, tUser.User.Sid, strAccountName, lngAccountLength, strDomainName, lngDomainLength, lngSIDTypeReturned)
                
                If retVal = 0 Then
                    MsgBox "LookUpAccountSid faild"
                End If
            
            End If

        End If

      End Sub