C / C++ / MFC

17-Dec-07 14:51

I really what read some information from my USB device.My two task are these:

1.When I scan a USB device plugged,I want to get its driver letter like G,H,and so on.For example,i get a device instance like "USB\VID_0AC8&PID_301B\5&37FD04DB&0&2" using SetupDiGetInterfaceDeviceDetail,so I using that path to create a HANDLE(using ZwOpenFile),then I want to call ZwQueryInformationFile() to get some information,or call ObReferenceObjectByHandle().But these functions are decleared in wdm.h or ntddk.h.

2.The document of my USB device(or storage)says that,the special information should be retrieve by SCSI INQUIRY,I find it is IOCTL_SCSI_GET_INQUIRY_DATA command.But I do not know how to do.

I will be very appreciated if someone give me some advice.
Thanks.

Naveen17-Dec-07 17:28

17-Dec-07 17:28

kcynic wrote:
.When I scan a USB device plugged,I want to get its driver letter like G,H,and so on.For example,i get a device instance like "USB\VID_0AC8&PID_301B\5&37FD04DB&0&2"

Now through which mehtod ur detecting the USB is plugged? WM_DEVICECHANGE?

nave

[OpenedFileFinder]

kcynic17-Dec-07 18:02

17-Dec-07 18:02

No,I only retrieve the USB device by accessing all the usb hub port to see whether there are some USB devices plugged in.

Naveen17-Dec-07 18:13

17-Dec-07 18:13

When a USB device is plugged, all the top level windows will receive a WM_DEVICECHANGE message. An in such case you can retrive the drive letter from the structure pointed by the LPARAM of that message. Check the MSDN for the help of WM_DEVICECHANGE.

nave

[OpenedFileFinder]

kcynic17-Dec-07 18:19

17-Dec-07 18:19

And my program is not a GUI project,only a console project,because there is no need to retrieve windows messages.In fact,my program would be run when the USB devices had been plugged in.By now,if there only has one specified USB device,my program works well,and if there are more than one such USB device,it does not know which USB device it really want to operate.(In addition,one such USB device can be treate as a mass storage.

Naveen17-Dec-07 18:58

17-Dec-07 18:58

ok. I can help u with the first task( calling the ZwOpenFile() and ZwQueryInformationFile()).

1 . copy all the necessary structure for those function from the ntddk.h file to ur local file
2. now create a pointer for that function. like

typedef NTSTATUS (*pZwOpenFile)(<br />
    OUT PHANDLE  FileHandle,<br />
    IN ACCESS_MASK  DesiredAccess,<br />
    IN POBJECT_ATTRIBUTES  ObjectAttributes,<br />
    OUT PIO_STATUS_BLOCK  IoStatusBlock,<br />
    IN ULONG  ShareAccess,<br />
    IN ULONG  OpenOptions<br />
    );

3. Now use LoadLibrary to load the ntdll.dll. HMODULE hModule = LoadLibrary( _T("ntdll.dll"));

4. Now call GetProcAddress() function to get of the ZwOpenFile function.
pZwOpenFile ZwOpenFile = (pZwOpenFile )GetProcAddress( hModule, "ZwOpenFile" );

now u can call ZwOpenFile like any other functions.

nave

[OpenedFileFinder]

kcynic17-Dec-07 19:06

17-Dec-07 19:06

Yes,that is a good idea.
And if you known some about the 2nd question?
Thank you very much.

Naveen17-Dec-07 19:23

17-Dec-07 19:23

may be u should call the DeviceIoControl() function with the input and output parameter specified in the IOCTL_SCSI_GET_INQUIRY_DATA[^]

nave

[OpenedFileFinder]

kcynic17-Dec-07 19:33

17-Dec-07 19:33

Yes,perhaps that can.
But I tried several times of the IOCTL_SCSI_GET_INQUIRY_DATA.But it faild for every of my USB stroage except my IDE storage.
I search the reason on the internet,someone said that,that ioctl would faild for usb device,but use SCSI_INQUIRY(operation code:0x12h) command to the device.
But I am not a driver programmer,I only a application programmer,so I only know a little about WDM.
I do not know how to do such task.

Naveen17-Dec-07 19:47

17-Dec-07 19:47

did u search in google. I found some sample that use SCSI_INQUIRY. One of them here[^]

nave

[OpenedFileFinder]

kcynic17-Dec-07 20:12

Re: Help about read data from a USB [modified]

17-Dec-07 20:12

In fact,not because I am lazy.I am a Chinese,so I read English a little slowly.On the other side,in my local area,the search engine will list the linkers in my own language priority.
By now,I do not know the liker you given to me works well or not,but I will have a try.
And I will learn English more hard.I can see,I will read English words as fast as reading my own language.

Thank you very much.

BEST WISHES.

JudyL_MD18-Dec-07 2:47

JudyL_MD

18-Dec-07 2:47

Repost of my answer in our earlier discussion, just so it is complete in the archives:

You can do this without using the functions from wdm and ntddk. After you get your device's name using the SetupDi functions, open a handle using CreateFile. Then use DeviceIoControl to send the IOCTL_SCSI_GET_INQUIRY_DATA to the device. Google on that IOCTL and you'll find some examples of calling it from user mode.

Judy

(fixed my cut-and-paste HTML)

modified on Tuesday, December 18, 2007 1:29:05 PM

Is there a C++ funtion like GetSystemDrive?

papafreebird17-Dec-07 7:28

papafreebird

17-Dec-07 7:28

Is there a C++ funtion like GetSystemDrive? Basically what I want is a way to get the system drive letter into a string.

This is sort of like What I want to do.

char BUFF[MAX_PATH] = {NULL};
GetWindowsDirectory(BUFF, MAX_PATH);
strcat(BUFF, "\\whatever\\Register.bat");

That would create a string "C:\windows\whatever\Register.bat"

What I really want is to create a string like this
"C:\whatever\Register.bat"

I just need a way to get the systems drive letter.

Any help would be appreciated.

Re: Is there a C++ funtion like GetSystemDrive?

papafreebird17-Dec-07 7:54

papafreebird

17-Dec-07 7:54

Well I'm answering my own question. I used Getenv("systemdrive")

char * BUFF;
BUFF = getenv ("SYSTEMDRIVE");

strcat( BUFF, "\\whatever\\Register.bat");

This produced C:\whatever\register.bat

Re: Is there a C++ funtion like GetSystemDrive?

only coding17-Dec-07 14:19

only coding

17-Dec-07 14:19

It is not safe to modify the value of the environment variable using the returned pointer.
By MSDN

Re: Is there a C++ funtion like GetSystemDrive?

David Crow17-Dec-07 8:47

David Crow

17-Dec-07 8:47

Just take the drive letter returned from GetWindowsDirectory().

Visual C++ 2008 programming for graphics

Anthony Appleyard17-Dec-07 6:19

Anthony Appleyard

17-Dec-07 6:19

I am trying to get a small Windows program to follow the example in http://msdn2.microsoft.com/en-us/library/ms533844.aspx , which reads an image from a .BMP and writes it to a .JPG . I have got it to compile, except for one persistent error: "'GetEncoderClsid': identifier not found". (This is the line afer the comment "// Get the CLSID of the JPEG encoder.".) Please, is this name GetEncoderClsid mistyped in the original? or what? Thanks.

toxcct17-Dec-07 6:29

toxcct

17-Dec-07 6:29

did you forget to forward declare it before the main() function ?

INT GetEncoderClsid(const WCHAR* format, CLSID* pClsid);  // helper function

or you didn't didn't include the function implementation, which is shown on a link above the code :

"The main function relies on the helper function GetEncoderClsid, which is shown in Retrieving the Class Identifier for an Encoder[^]"

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Anthony Appleyard17-Dec-07 6:41

Anthony Appleyard

17-Dec-07 6:41

Thanks. I inserted the line

INT GetEncoderClsid(const WCHAR* format, CLSID* pClsid); // helper function

and it caused successful compilation but this link error:

unresolved external symbol "int __cdecl GetEncoderClsid(wchar_t const *,struct _GUID *)" (?GetEncoderClsid@@YAHPB_WPAU_GUID@@@Z) referenced in function "long __stdcall WndProc(struct HWND__ *,unsigned int,unsigned int,long)" (?WndProc@@YGJPAUHWND__@@IIJ@Z)

toxcct17-Dec-07 6:44

toxcct

17-Dec-07 6:44

YES !

follow the link[^] I gave you, which I got from you original link. the code of the method is there. copy it and paste it in your project.

D'Oh! | :doh:

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Anthony Appleyard17-Dec-07 6:53

Anthony Appleyard

17-Dec-07 6:53

Thanks. It worked!!!!!!!!!!!!!!. It copied a BMP file to a JPG file with modew conversion, like I wanted. Thanks everybody.