Re: Reading a USB device - C / C++ / MFC Discussion Boards

Re: Reading a USB device

David Crow27-Mar-08 8:16

David Crow

27-Mar-08 8:16

So then can't you call ReadFile()?

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Re: Reading a USB device

koumodaki27-Mar-08 8:25

koumodaki

27-Mar-08 8:25

I have a file context.cfg which needs to be read form the flash drive. How do I specify in the ReadFile() parameters that I need to read this particular file. From what I know, I can pass the handle I obtain while opening the usb flash drive from CreateFile() to this function. How do I get hold of the file inside the flash drive

Re: Reading a USB device

David Crow27-Mar-08 8:34

David Crow

27-Mar-08 8:34

What does your call to CreateFile() look like?

Re: Reading a USB device

koumodaki27-Mar-08 9:13

koumodaki

27-Mar-08 9:13

I enumarate the USB device first and get the interface using SetupDiGetDeviceInterfaceDetail(). The name is stored in a vector Devices. Then I use the following call:
HANDLE hUsbDevice = CreateFile(Devices[0].c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);

Re: Reading a USB device

David Crow27-Mar-08 9:17

David Crow

27-Mar-08 9:17

So what happens if you use:

string str = Devices[0] + "\\context.cfg";
HANDLE hUsbDevice = CreateFile(str.c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);

Re: Reading a USB device

koumodaki27-Mar-08 9:20

koumodaki

27-Mar-08 9:20

Havent tried that. Will check it out

Re: Reading a USB device

koumodaki27-Mar-08 9:31

koumodaki

27-Mar-08 9:31

I tried the method you suggested. I did not work. The code snippet is

std::string path = Devices[0] + "\\context.cfg";
HANDLE hUsbDevice = CreateFile(Devices[0].c_str(), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
if (hUsbDevice == INVALID_HANDLE_VALUE)
return 1;

char data[MAX_PATH];
DWORD nNumberOfBytesToRead = MAX_PATH;
DWORD lpNumberOfBytesRead = 0;

if(!ReadFile(hUsbDevice,(void*)data, nNumberOfBytesToRead, &lpNumberOfBytesRead,NULL))
{
int err = GetLastError();
return 0;
}

GetLastError() returns ERROR_INVALID_PARAMETER

Re: Reading a USB device

David Crow27-Mar-08 9:34

David Crow

27-Mar-08 9:34

koumodaki wrote:
I tried the method you suggested.

But the code snippet you posted does not reflect such. You are not using path.

I like Judy's suggestion better.

Re: Reading a USB device

koumodaki27-Mar-08 9:40

koumodaki

27-Mar-08 9:40

I used the path but made a mistake while copying the code here. Ok so maybe I will try using WMI.
Do you have any tutorial which explains how to use Windows API in such situatuons?

Re: Reading a USB device

JudyL_MD27-Mar-08 9:31

JudyL_MD

27-Mar-08 9:31

koumodaki wrote:
I can pass the handle I obtain while opening the usb flash drive from CreateFile() to this function.

The problem is that this handle is a handle to the physical drive. You can't use that to easily find a file on the drive.

Your basic problem is how to convert from a USB identifier to the logical hard drive letter. Using WMI you can go from something like USBSTOR\\DISK&VEN_SANDISK&PROD_CRUZER_MINI&REV_0.1\\20041100801E102869&0 (to take an example not at random) to G:. Stick the USB flash in your system, fire up the WMI object browser and you can see the queries you need to make to WMI to go from the former to the latter.

Judy

Re: Reading a USB device

koumodaki27-Mar-08 9:41

koumodaki

27-Mar-08 9:41

Thanks Judy. I will try this

Re: Reading a USB device

David Crow27-Mar-08 10:14

David Crow

27-Mar-08 10:14

JudyL_FL wrote:
...fire up the WMI object browser and you can see the queries you need to make to WMI to go from the former to the latter.

Interesting tool. I inserted a PNY Attache drive and tried it.

I found "E:" under the Win32_LogicalDisk node, and "USB\VID_154B&PID_0005\6E68190046F6" under the Win32_USBHub node. I then found "USBSTOR\DISK&VEN_PNY&PROD_USB_2.0_FD&REV_PMAP\6E68190046F6&0" under the Win32_DiskDrive node.

Where are these queries to which you refer?

Re: Reading a USB device

JudyL_MD27-Mar-08 10:25

JudyL_MD

27-Mar-08 10:25

If you follow Win32_SystemDevices to Win32_PnPEntity, you should find a leaf with a device id something like USBSTOR.....
From there, you can get (look under Win32_PnPDevice) the correct DeviceId to use for Win32_DiskDrive.
From there, you can get (look under Win32_DiskDriveToDiskPartition) the correct DeviceId to use for Win32_DiskPartition.
From there, you can get (look under Win32_LogicalDiskToPartition) the correct DeviceId to use for Win32_LogicalDisk.
That final device id is the logical drive number.

(Whew!! <wiping brow="">)

Getting that first USBSTOR... monster string is what's usually the hardest part of this sort of thing since you have to use the SetupDi API. That is truly nasty!!

Judy

Re: Reading a USB device

David Crow27-Mar-08 10:30

David Crow

27-Mar-08 10:30

Wow! I need an elevator to come back to the surface from drilling down that deep. It works, though.

Automatically generate serialization code?

Adrian Idar (Ln)27-Mar-08 5:53

Adrian Idar (Ln)

27-Mar-08 5:53

I'm looking for a way of identifying the data members of a number of classes that need to be serialized

Boost serialization would be used - but what I'm looking for is a way to automatically generate the serialization helpers.

The idea would be to:
1) Run an utility (parser) that scans the C++ code and identifies the data members
2) From the data members generate .inl files (one for each class) that would contain the boost::serialize() method
3) Have the .inl files included in the corresponding cpps
4) Compile and link...

These are classes that are modified on a daily basis by other people. Maintaining the serialization code manually would not be an option - looking for an automated way.

Definitely someone else had solved this problem (with this approach or a different one). Let me know if you know anything about that.

Thanks,
Adrian

Re: Automatically generate serialization code?

CPallini27-Mar-08 6:00

CPallini

27-Mar-08 6:00

Adrian R. wrote:
2) From the data members generate .inl files (one for each class) that would contain the boost::serialize() method

What about pointers?

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

Gdiplus::Bitmap will using a file in read-exclusive mode?

followait27-Mar-08 5:11

followait

27-Mar-08 5:11

I'm using a Gdiplus::Bitmap object as a buffer bitmap.
When do some, I can't open the file used by the bitmap in CFile::modeRead mode.
Is there any mehod to make it read-share?

how to hook the window API such as messagebox? thanks

King Tran27-Mar-08 5:10

King Tran

27-Mar-08 5:10

i want to hook the windows API such as messagebox, i find the code in the net, but it dosn't work, why? the code as follows:

typedef struct tag_HOOKAPI
{
LPCSTR szFunc;
PROC pNewProc;
PROC pOldProc;
}HOOKAPI, *LPHOOKAPI;

HOOKAPI api[1];
api[0].szFunc ="MessageBoxA";
api[0].pNewProc = (PROC)MessageBoxA1;
HookAPIByName(GetModuleHandle(NULL),"User32.dll",&api[0]);

extern "C" __declspec(dllexport)PIMAGE_IMPORT_DESCRIPTOR
LocationIAT(HMODULE hModule, LPCSTR szImportMod)

{

PIMAGE_DOS_HEADER pDOSHeader = (PIMAGE_DOS_HEADER) hModule;
if(pDOSHeader->e_magic != IMAGE_DOS_SIGNATURE) return NULL;
PIMAGE_NT_HEADERS pNTHeader = (PIMAGE_NT_HEADERS)((DWORD)pDOSHeader+
(DWORD)(pDOSHeader->e_lfanew));
if(pNTHeader->Signature != IMAGE_NT_SIGNATURE) return NULL;
if(pNTHeader->OptionalHeader.DataDirectory
[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress == 0)
return NULL;

PIMAGE_IMPORT_DESCRIPTOR pImportDesc =
(PIMAGE_IMPORT_DESCRIPTOR)((DWORD)pDOSHeader + (DWORD)
(pNTHeader->OptionalHeader.DataDirectory
[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress));

while (pImportDesc->Name)
{
PSTR szCurrMod = (PSTR)((DWORD)pDOSHeader +
(DWORD)(pImportDesc->Name));
if (stricmp(szCurrMod, szImportMod) == 0) break;
pImportDesc++;
}
if(pImportDesc->Name == NULL) return NULL;
return pImportDesc;
}

extern "C" __declspec(dllexport) HookAPIByName( HMODULE hModule, LPCSTR szImportMod, LPHOOKAPI pHookApi)

{
PIMAGE_IMPORT_DESCRIPTOR pImportDesc = LocationIAT(hModule, szImportMod);
if (pImportDesc == NULL) return FALSE;

PIMAGE_THUNK_DATA pOrigThunk = (PIMAGE_THUNK_DATA)((DWORD)hModule + (DWORD)(pImportDesc->OriginalFirstThunk));

PIMAGE_THUNK_DATA pRealThunk = (PIMAGE_THUNK_DATA)((DWORD)hModule + (DWORD)(pImportDesc->FirstThunk));

while(pOrigThunk->u1.Function)
{
if((pOrigThunk->u1.Ordinal & IMAGE_ORDINAL_FLAG) != IMAGE_ORDINAL_FLAG)
{
PIMAGE_IMPORT_BY_NAME pByName =(PIMAGE_IMPORT_BY_NAME)((DWORD)hModule+(DWORD)(pOrigThunk->u1.AddressOfData));
if(pByName->Name[0] == '\0') return FALSE;
if(strcmpi(pHookApi->szFunc, (char*)pByName->Name) == 0)
{
MEMORY_BASIC_INFORMATION mbi_thunk;
VirtualQuery(pRealThunk, &mbi_thunk, sizeof(MEMORY_BASIC_INFORMATION));
VirtualProtect(mbi_thunk.BaseAddress,mbi_thunk.RegionSize, PAGE_READWRITE, &mbi_thunk.Protect);

if(pHookApi->pOldProc == NULL)
pHookApi->pOldProc = (PROC)pRealThunk->u1.Function;

pRealThunk->u1.Function = (PDWORD)pHookApi->pNewProc;
DWORD dwOldProtect;
VirtualProtect(mbi_thunk.BaseAddress, mbi_thunk.RegionSize, mbi_thunk.Protect, &dwOldProtect);
}
}
pOrigThunk++;
pRealThunk++;
}
SetLastError(ERROR_SUCCESS);
return TRUE;
}

static int WINAPI MessageBoxA1 (HWND hWnd , LPCTSTR lpText, LPCTSTR lpCaption, UINT uType)
{

return MessageBox(hWnd, "Hook API OK!", "Hook API", uType);
}

Re: how to hook the window API such as messagebox? thanks

James R. Twine27-Mar-08 7:32

James R. Twine

27-Mar-08 7:32

   OK - you are not getting any replies because of the following issues, which I suggest you correct ASAP:

     1: You code snippet neets to be inbetween <PRE> tags

     2: In order to ask why something does not work, you have to specify what exactly is not working (error codes, crashes, etc.)

   I have successfully used a CBT hook to capture, log the contents of, and pop MessageBox(...)-based dialogs successfully in the past, so I know this is not too hard.

   Peace!

-=- James
Please rate this message - let me know if I helped or not!<hr></hr>If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
See DeleteFXPFiles

Re: how to hook the window API such as messagebox? thanks

Stephen Hewitt27-Mar-08 14:35

Stephen Hewitt

27-Mar-08 14:35

1. Format your code so it's readable. I know it's a pain, but it's also a pain from this end: I don't even bother to look at such messes.
2. What's going wrong?

Steve

Re: how to hook the window API such as messagebox? thanks

King Tran29-Mar-08 2:45

King Tran

29-Mar-08 2:45

yes, it was my fault to post such long and boring code!

but ,frankly to say, i got the code from the website, i didn't understand it with my little HOOK and DLL knoledge. i debuged the code , and found that it cound not get the User32.dll IAT location, i didn't know the matter.

my aim is to hook the window API , such as messagebox or winsocket, would you please give me some help? refering materials or codes?

thanks! Smile | :)

Help me please

Member 417463927-Mar-08 4:31

Member 4174639

27-Mar-08 4:31

I have exe file generated of compile C++ code using Microsoft Visual Studio 2005 on my Laptop , and i need to take this exe file to run it on my pocket PC.

Is it possible to run this exe file on pocket PC ?????
ahmed.rayan@hotmail.com

Re: Help me please