USB Device Removal Notifications

[tristanlbailey]

Hello.

I'm trying to create a program in Visual Basic 6 that detects when a user is attempting to remove a USB drive, by using the "Safely Remove Hardware" icon on the taskbar. There is supposed to be a message (DBT_DEVICEQUER YREMOVE) that the Windows Operating System broadcasts to applications that are "listening" for it. I'm trying to utilise this message to prevent the removal of the device.

It has been stated on the MSDN site, that you need to use the DEV_BROADCAST_H ANDLE structure, open a file on the USB drive, and insert the file's handle into the structure; followed by a call to the system's RegisterDeviceN otification function.

I have successfully received the DBT_DEVICEARRIV AL and DBT_DEVICEREMOV ECOMPLETE messages by using the DEV_BROADCAST_D EVICEINTERFACE structure, but I'm having troubles using the DEV_BROADCAST_H ANDLE structure. It fails at the RegisterDeviceN otification line, returning a standard error code of 0, and a DLL error code of 1066.

Declarations:
[CODE=VB]Public Declare Function CallWindowProcA Lib "user32" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Function CreateFileA Lib "kernel32" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, ByVal lpSecurityAttri butes As Long, ByVal dwCreationDispo sition As Long, ByVal dwFlagsAndAttri butes As Long, ByVal hTemplateFile As Long) As Long
Public Declare Function RegisterDeviceN otificationA Lib "user32" (ByVal hRecipient As Long, NotificationFil ter As DEV_BROADCAST_H ANDLE, ByVal Flags As Long) As Long
Public Declare Function SetWindowLongA Lib "user32" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Type GUID
D1(3) As Byte
D2(1) As Byte
D3(1) As Byte
D4(7) As Byte
End Type

Public Type DEV_BROADCAST_D EVICEINTERFACE
dbcc_size As Long
dbcc_devicetype As Long
dbcc_reserved As Long
dbcc_classguid As GUID
dbcc_name As String
End Type

Public Type DEV_BROADCAST_H ANDLE
dbch_size As Long
dbch_devicetype As Long
dbch_reserved As Long
dbch_handle As Long
dbch_devnotify As Long
dbch_eventguid As GUID
dbch_nameoffset As Long
dbch_data(1023) As Byte
End Type

Public Const DBT_DEVICEQUERY REMOVE As Long = 32769
Public Const DBT_DEVTYP_DEVI CEINTERFACE As Long = 5
Public Const DBT_DEVTYP_HAND LE As Long = 6
Public Const DEVICE_NOTIFY_W INDOW_HANDLE As Long = 0
Public Const DEVICE_NOTIFY_A LL_INTERFACE_CL ASSES As Long = 4
Public Const FILE_ATTRIBUTE_ NORMAL As Long = 128
Public Const FILE_SHARE_READ As Long = 1
Public Const GENERIC_READ As Long = &H80000000
Public Const GWL_WNDPROC As Long = -4
Public Const WM_DEVICECHANGE As Long = &H219
[/CODE]

General Code:
[CODE=VB]
Function WindowProc(ByVa l hWnd As Long, ByVal uMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

If uMsg = WM_DEVICECHANGE Then
MsgBox "DeviceChan ge message received. " & wParam & " " & lParam
If wParam = DBT_DEVICEQUERY REMOVE Then
MsgBox "DeviceQueryRem ove message received."
End If
End If

WindowProc = CallWindowProcA (hUSBProc, hWnd, uMsg, wParam, lParam)

End Function

Sub Main

Form1.Hide
hFile = CreateFileA("E: \MYFILE.TXT", GENERIC_READ, FILE_SHARE_READ , 0, OPEN_EXISTING, FILE_ATTRIBUTE_ NORMAL, 0)
With USBNotify
.dbch_size = Len(USBNotify)
.dbch_devicetyp e = DBT_DEVTYPE_HAN DLE
.dbch_reserved = 0
.dbch_handle = hFile
End With
I = RegisterDeviceN otificationA(Fo rm1.hWnd, USBNotify, DEVICE_NOTIFY_W INDOW_HANDLE Or DEVICE_NOTIFY_A LL_INTERFACE_CL ASSES)
hUSBProc = SetWindowLongA( Form1.hWnd, GWL_WNDPROC, AddressOf WindowProc)

End Sub
[/CODE]

[daniel aristidou]

Hello.

I'm trying to create a program in Visual Basic 6 that detects when a user is attempting to remove a USB drive, by using the "Safely Remove Hardware" icon on the taskbar. There is supposed to be a message (DBT_DEVICEQUER YREMOVE) that the Windows Operating System broadcasts to applications that are "listening" for it. I'm trying to utilise this message to prevent the removal of the device.

It has been stated on the MSDN site, that you need to use the DEV_BROADCAST_H ANDLE structure, open a file on the USB drive, and insert the file's handle into the structure; followed by a call to the system's RegisterDeviceN otification function.

I have successfully received the DBT_DEVICEARRIV AL and DBT_DEVICEREMOV ECOMPLETE messages by using the DEV_BROADCAST_D EVICEINTERFACE structure, but I'm having troubles using the DEV_BROADCAST_H ANDLE structure. It fails at the RegisterDeviceN otification line, returning a standard error code of 0, and a DLL error code of 1066.

hmmm not sure if its relevant but might be...
Have you checked the program on a different pc or with a different operating system.
it might be the os that is to blame

[tristanlbailey]

The main Windows Operating System that I use to test programs on is Windows XP. I don't see why this sort of code shouldn't work on Windows XP.

I plan to use the program on multiple Windows Operating System platform versions (i.e. Windows 98, Me, NT, 2000, etc.), however. I believe all of the necessary API functions exist within each of these versions.

[tristanlbailey]

I'm still looking for a way of getting the program to pick up the DBT_DEVICEQUERY REMOVE message. I have satisfied the RegisterDeviceN otification function by providing a handle to the USB device, but still can't get the message.

Here's the updated version:

Declarations:

Public Declare Function CallWindowProcA Lib "user32" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Function CreateFileA Lib "kernel32" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, ByVal lpSecurityAttributes As Long, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
Public Declare Function RegisterDeviceNotificationA Lib "user32" (ByVal hRecipient As Long, NotificationFilter As DEV_BROADCAST_HANDLE, ByVal Flags As Long) As Long
Public Declare Function SetWindowLongA Lib "user32" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Type GUID
    D1 As Long
    D2 As Integer
    D3 As Integer
    D4(7) As Byte
End Type

Public Type DEV_BROADCAST_HANDLE
    dbch_size As Long
    dbch_devicetype As Long
    dbch_reserved As Long
    dbch_handle As Long
    dbch_devnotify As Long
    dbch_eventguid As GUID
    dbch_nameoffset As Long
    dbch_data As Byte
End Type

Public Const DBT_DEVICEQUERYREMOVE As Long = 32769
Public Const DBT_DEVTYP_HANDLE As Long = 6
Public Const DEVICE_NOTIFY_WINDOW_HANDLE As Long = 0
Public Const FILE_SHARE_READ As Long = 1
Public Const FILE_SHARE_WRITE As Long = 2
Public Const GENERIC_READ As Long = &H80000000
Public Const GWL_WNDPROC As Long = -4
Public Const WM_DEVICECHANGE As Long = 537

Public hFile As Long, hUSBProc As Long
Public USBNotify As DEV_BROADCAST_HANDLE

General Code:

Function WindowProc(ByVal hWnd As Long, ByVal uMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long

    If uMsg = WM_DEVICECHANGE Then
        MsgBox "DeviceChange message received. " & wParam & " " & lParam
        If wParam = DBT_DEVICEQUERYREMOVE Then
		'Still not working!
		MsgBox "DeviceQueryRemove message received."
        End If
    End If
    
    WindowProc = CallWindowProcA(hUSBProc, hWnd, uMsg, wParam, lParam)

End Function

Sub Main

    Form1.Hide
    hFile = CreateFileA("USB Mass Storage Device", GENERIC_READ, FILE_SHARE_READ Or FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0)
    With USBNotify
        .dbch_size = LenB(USBNotify)
        .dbch_devicetype = DBT_DEVTYPE_HANDLE
        .dbch_handle = hFile
    End With
    I = RegisterDeviceNotificationA(Form1.hWnd, USBNotify, DEVICE_NOTIFY_WINDOW_HANDLE)
    hUSBProc = SetWindowLongA(Form1.hWnd, GWL_WNDPROC, AddressOf WindowProc)

End Sub

If anyone has the answer, your help would be greatly appreciated.