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500 points Win2000 NTFS question

I give 500 points for this question:

I need to read a Win2000 encrypted file and then write its entire contents to an other file using ReadEncryptedFileRaw/WriteEncryptedFileRaw APIs from advapi.dll

These APIs seem not to work properly. This is the code I use:


BYTE      g_Buf[10000];
DWORD       g_BufLen;
void   *d_pv;


DWORD RRead(PBYTE pbData, PVOID pvCallbackContext, ULONG ulLength)
{
      memcpy(g_Buf, pbData, ulLength);
      g_BufLen = ulLength;

      return 0;
}


DWORD WWrite(PBYTE pbData, PVOID pvCallbackContext, PULONG ulLength)
{
      memcpy(pbData, g_Buf, g_BufLen);
      *ulLength = g_BufLen;

      return 0;
}


OpenEncryptedFileRaw("c:\\Test.txt", 0, &g_pv);
ReadEncryptedFileRaw((PFE_EXPORT_FUNC)RRead, NULL, g_pv);
CloseEncryptedFileRaw(g_pv);

OpenEncryptedFileRaw("c:\\TestCpy.txt", CREATE_FOR_IMPORT, &g_pv);
WriteEncryptedFileRaw((PFE_IMPORT_FUNC)WWrite, NULL, g_pv);
CloseEncryptedFileRaw(g_pv);

What is wrong with this code?
0
alex1234
Asked:
alex1234
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1 Solution
 
NickRepinCommented:
For 500 points + grade A, I'll answer this question.
But you have to increase the points first.
0
 
alex1234Author Commented:
What is "grade A" and how many points do you want?
0
 
NickRepinCommented:
The title of your question is "500 points Win2000 NTFS question".
But the actual price is ZERO.
So, increase the actual price to 500 points, and I'll answer your question.
0
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alex1234Author Commented:
Adjusted points from 0 to 500
0
 
alex1234Author Commented:
Go ahead...

However, I won't accept the answer if these APIs don't work just because of a bug in Windows files (advapi.dll or somewhere else). In this case please don't post the "answer", just use "comments" so I could delete this question later and not to loose the points.
0
 
NickRepinCommented:
Don't worry, it works fine...

#include <windows.h>
#include <iostream.h>

//----------------------------
// There is a bug in the winbase.h, at least
// in my Platform SDK RC2.
// Callback functions must be defined as WINAPI:
//
// DWORD (WINAPI *PFE_EXPORT_FUNC)(...)
// DWORD (WINAPI *PFE_IMPORT_FUNC)(...)
//
//----------------------------


// The buffer must be large enough.
BYTE g_Buf[1024*1024*10];
DWORD g_BufLen=0,written=0;
PVOID pContext;

//
// Callbacks must be defined with WINAPI
//
DWORD WINAPI RRead(PBYTE pbData, PVOID /*pvCallbackContext*/, ULONG ulLength)
{
   cout<<"Read callback, len="<<ulLength<<endl;
   memcpy(g_Buf+g_BufLen,pbData,ulLength);
   g_BufLen+=ulLength;    
   return ERROR_SUCCESS;
}


DWORD WINAPI WWrite(PBYTE pbData,PVOID /*pvCallbackContext*/, PULONG ulLength)
{
   cout<<"Write callback, len="<<*ulLength;
   if(*ulLength>g_BufLen) *ulLength=g_BufLen;
   cout<<", used="<<*ulLength<<endl;
   memcpy(pbData,g_Buf+written,*ulLength);
   written+=*ulLength;
   g_BufLen-=*ulLength;
   return ERROR_SUCCESS;
}

void main()
{

   DWORD r;

   r=OpenEncryptedFileRaw("d:\\aa", 0, &pContext);
   cout<<"Open result="<<r<<' '<<GetLastError()<<endl;
   r=ReadEncryptedFileRaw((PFE_EXPORT_FUNC)RRead,0,pContext);
   cout<<"Read result="<<r<<' '<<GetLastError()<<endl;
   cout<<"Buf len="<<g_BufLen<<endl;
   CloseEncryptedFileRaw(pContext);
   cout<<"Closed "<<endl<<endl;

   r=OpenEncryptedFileRaw("d:\\aa2", CREATE_FOR_IMPORT, &pContext);
   cout<<"Open result="<<r<<' '<<GetLastError()<<endl;
   r=WriteEncryptedFileRaw((PFE_IMPORT_FUNC)WWrite,0,pContext);
   cout<<"Write result="<<r<<' '<<GetLastError()<<endl;
   CloseEncryptedFileRaw(pContext);
   cout<<"Closed "<<endl;
}
0
 
NickRepinCommented:
The answer is above
0
 
alex1234Author Commented:
// There is a bug in the winbase.h, at least
// in my Platform SDK RC2.
// Callback functions must be defined as WINAPI:

Nick,

that is exactly what I suspected: a bug in Windows files. I just couldn'd find where...
This "WINAPI" declaration makes whole the difference. Anyway, I accept your answer. Thanks.  
0
 
NickRepinCommented:
Also you incorrectly used callback functions...
0
 
alex1234Author Commented:
My callback functions were used for a "single callback" call only (really small file). The whole idea is those WINAPI. Whithout WINAPI callback functions get called only one time.
0

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