problem regrading PIMAGE_DOS_HEADER

My program code is given bellow.....

Code:

#include <windows.h>
#include <stdio.h>
#include <conio.h>
#include<winnt.h>

#define BUF_SIZE 256
TCHAR szName[]=TEXT("process.c");
TCHAR szMsg[]=TEXT("Message from first process");

int main()
{
   HANDLE hMapFile;
   LPCTSTR pBuf;
   PIMAGE_NT_HEADERS pimage_nt_headers;

   hMapFile = CreateFileMapping(
                 INVALID_HANDLE_VALUE,    // use paging file
                 NULL,                    // default security 
                 PAGE_READWRITE,          // read/write access
                 0,                       // max. object size 
                 BUF_SIZE,                // buffer size  
                 szName);                 // name of mapping object
 
   if (hMapFile == NULL || hMapFile == INVALID_HANDLE_VALUE) 
   { 
      printf("Could not create file mapping object (%d).\n", 
             GetLastError());
      return 1;
   }
   pBuf = (LPTSTR) MapViewOfFile(hMapFile,   // handle to map object
                        FILE_MAP_ALL_ACCESS, // read/write permission
                        0,                   
                        0,                   
                        BUF_SIZE);           

   printf("%d",pBuf);
   if (pBuf == NULL) 
   { 
      printf("Could not map view of file (%d).\n", 
             GetLastError()); 
      return 2;
   }

   CopyMemory((PVOID)pBuf, szMsg, strlen(szMsg));
  
   PIMAGE_DOS_HEADER pimage_dos_header = PIMAGE_DOS_HEADER(pBuf);

   pimage_nt_headers = (PIMAGE_NT_HEADERS)
    (pBuf + pimage_dos_header->e_lfanew);
   printf("\n%d\n",pimage_nt_headers);
   DWORD it_voffset = pimage_nt_headers->OptionalHeader.
   DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress;

  printf("%d",it_voffset);
   getch();

   UnmapViewOfFile(pBuf);

   CloseHandle(hMapFile);

   return 0;
}

when i am displaying the value in it_voffset .....it is showing 0.
why it is so ?
can anyone explain this.......
pBuf is having valid value......

Why are you displaying it in double? (%d)

hii

i should use %lu in place of %d .. but even after using it i am still getting 0.

> TCHAR szName[]=TEXT("process.c");
Maybe it's something to do with the fact that you're looking for an exe header in something which isn't an exe file.

MSDN says:
If hFile is INVALID_HANDLE_VALUE, the calling process must also specify a mapping object size in the dwMaximumSizeHigh and dwMaximumSizeLow parameters. In this scenario, CreateFileMapping creates a file mapping object of a specified size that the operating system paging file backs, instead of by a named file in the file system.

What does it actually do? Open process.c file as a PE executable to see the virtual addresses of that "program's" sections?

As maxorator said, your code does not actually open process.c (the last argument to CreateFileMapping is the name of the file mapping object, not a filename), and as Salem said, even if it did, process.c is unlikely to contain an executable header.

There is an example of mapping a file for read access.

could u please explain how to open process.c as a PE executable .
actually i am new to windows programming

process.c is most likely a source file, not a portable executable, and should not tried to be opened as such. any executable, .exe extension, is probably a portable executable.

Code:

#include <windows.h>
#include <stdio.h>


//#include <windows.h>
//#include <stdio.h>
#include <conio.h>
#include<winnt.h>

#define BUF_SIZE 256
TCHAR szName[]=TEXT("process.c");
TCHAR szMsg[]=TEXT("Message from first process");
/*
 * Map a file for read access. Returns size of view in lpcbSize
 */
LPCTSTR MapFileRead(LPCTSTR szFileName, size_t * lpcbSize)
{
	HANDLE hFile, hMapping;
	DWORD  dwFileSize;
	LPCTSTR lpView;
	MEMORY_BASIC_INFORMATION mbi;

	HANDLE hMapFile;
   LPCTSTR pBuf;
   PIMAGE_NT_HEADERS pimage_nt_headers;

	*lpcbSize = 0;

	hFile = CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ, NULL,
	                   OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if (INVALID_HANDLE_VALUE == hFile)
	{
		return NULL;
	}

	dwFileSize = GetFileSize(hFile, NULL);
	if (INVALID_FILE_SIZE == dwFileSize)
	{
		CloseHandle(hFile);
		return NULL;
	}

	hMapping = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, NULL);
	if (NULL == hMapping)
	{
		CloseHandle(hFile);
		return NULL;
	}

	lpView = (LPTSTR)MapViewOfFile(hMapping, FILE_MAP_READ, 0, 0, 0);

printf("%d",lpView);


	  
   PIMAGE_DOS_HEADER pimage_dos_header = PIMAGE_DOS_HEADER(lpView);
   printf("%d...",pimage_dos_header->e_lfanew+lpView);

   pimage_nt_headers = (PIMAGE_NT_HEADERS)
   (lpView + pimage_dos_header->e_lfanew);
   DWORD it_voffset = pimage_nt_headers->OptionalHeader.
   DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress;  printf("%lu",it_voffset);
   getch();


	CloseHandle(hMapping);
	CloseHandle(hFile);

	if (NULL != lpView)
	{
		if (VirtualQuery(lpView, &mbi, sizeof(mbi)) >= sizeof(mbi))
		{
			*lpcbSize = min(dwFileSize, mbi.RegionSize);
		}
		else
		{
			*lpcbSize = dwFileSize;
		}
	}

	return lpView;
}


/*
 * Close a file mapping view.
 */
BOOL MapFileClose(LPCVOID lpView)
{
	return UnmapViewOfFile(lpView);
}


int main(void)
{
	size_t cbSize, i;
	const char * file_view;

	file_view = (const char *) MapFileRead(TEXT("const.cpp"), &cbSize);

	if (file_view)
	{
		try
		{
			for (i = 0;i < cbSize; i++)
			{
				printf("%c", file_view[i]);
			}
		}
		catch (...)
		{
			printf("Oh oh, not good doctor.");
		}

		MapFileClose(file_view);
	}

	getchar();
	return 0;
}

Code is given above .....

the point where i am getting error is underlined in italic...
and error is Memory could not be read

> printf("%c", file_view[i]);
This will just puke on a binary file.

> file_view = (const char *) MapFileRead(TEXT("const.cpp"), &cbSize);
How about trying to read your .exe file instead of your source file?
3 people have said the same thing now, but you still don't seem to get it.