ReadFile fails with ERROR_INVALID_FUNCTION when trying to read volume

Question

Hi,

 I am writing a application which copies the one volume to another (Volume Copy). When we try to read from volume using ReadFile API we get a error code ERROR_INVALID_FUNCTION. What are the reasons ans solution to this problem?

I am using W2k3 system

I am having Admin access(I can open the volume. CreateFile returns success)

Memory allocated using VirtualAlloc which is aligned

// VolumeRead.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <windows.h>
#include <conio.h>
#include <iostream>
#include <string>
using namespace std;

HANDLE gvolumehandle;
int gbuffsize = 1024*1024*10;// 10 MB data read for test

// This function enables backup and restore priviliges for this process. If
// the priviliges are not granted that is silently ignored.
BOOL
EnableBackupPrivileges()
{
    HANDLE hToken;
    BYTE buf[sizeof(TOKEN_PRIVILEGES) * 3];
    TOKEN_PRIVILEGES *tkp = (TOKEN_PRIVILEGES *) buf;

    if (!OpenProcessToken(GetCurrentProcess(),
        TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hToken))
        return FALSE;
	 

    if (!LookupPrivilegeValue(NULL, SE_BACKUP_NAME, &tkp->Privileges[0].Luid))
        return FALSE;

	
    if (!LookupPrivilegeValue(NULL, SE_RESTORE_NAME, &tkp->Privileges[1].Luid))
        return FALSE;

	if (!LookupPrivilegeValue(NULL, SE_SECURITY_NAME, &tkp->Privileges[2].Luid))
        return FALSE;

    tkp->PrivilegeCount = 3;
    tkp->Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
    tkp->Privileges[1].Attributes = SE_PRIVILEGE_ENABLED;
	tkp->Privileges[2].Attributes = SE_PRIVILEGE_ENABLED;

    return AdjustTokenPrivileges(hToken, FALSE, tkp, sizeof buf, NULL, NULL);
}

int OpenVolume(wstring volumename)
{
	DWORD accessflags = GENERIC_READ|FILE_GENERIC_READ;
	DWORD sharemode = FILE_SHARE_READ|FILE_SHARE_WRITE;
	DWORD creationflags = OPEN_EXISTING;
	DWORD attributes = FILE_FLAG_BACKUP_SEMANTICS |FILE_FLAG_SEQUENTIAL_SCAN;
	
	wstring volname = volumename;
	volname += L":";
	volname += L"\\";
	
	WCHAR volumenamebuffer[1024] = {0};
	int volumenamebufferlength = 1024;

	wcout << L"Getting volume name for volume " << volumename << L"\n";

	if( 0 == GetVolumeNameForVolumeMountPoint(volname.c_str(),volumenamebuffer,volumenamebufferlength))
	{		
		DWORD status = ::GetLastError();
		cout << "Getting volume name for volume " << volumename.c_str() << " failed. Error code = " <<status << "\n";
		return FALSE;
	}

	volname = volumenamebuffer;

	wcout << L"Opening volume " << volname << L"\n";

	HANDLE temphandle = INVALID_HANDLE_VALUE;
	gvolumehandle = CreateFile(volname.c_str(),accessflags,sharemode,NULL,creationflags,attributes,temphandle);
	if(INVALID_HANDLE_VALUE == gvolumehandle)
	{
		DWORD status = ::GetLastError();
		wcout << L"Opening volume " << volname<< L" failed. Error code = " <<status<< L"\n";
		return FALSE;
	}

	wcout << L"Opening volume " << volname << L" completed." << L"\n";
	return TRUE;
}

int ReadVolume(BYTE* buffstart, int buffsize)
{
	DWORD bytestoread = buffsize;
	DWORD actualbytesread = 0;
	DWORD totalbytesread = 0;
	
	while(1)
	{		
		int status = ReadFile(gvolumehandle,
								buffstart+totalbytesread,
								bytestoread,
								&actualbytesread,
								NULL);		

		// update remaining bytes
		bytestoread -= actualbytesread;

		// update total bytes
		totalbytesread += actualbytesread;

		// check for read complete
		if(status != 0)
		{
			//read successfull
			if(totalbytesread == buffsize)
			{
				//successfully read all bytes				
				return true;
			}	
			else
			{
				// we read some bytes only so continue reading				
				continue;
			}
		}	
		else
		{		
			// read failed
			DWORD errorcode = ::GetLastError();
			if(errorcode  == ERROR_HANDLE_EOF)
			{			
				cout << "ReadFile failed. no more data to read. Error code = " << errorcode << "\n";
				return true;
			}
			return false;
		}
	}
	return false;	
}


int ReadVolume(wstring sourcevolume)
{
	cout << "Opening volume.\n";
	if(TRUE != OpenVolume(sourcevolume))
	{
		cout << "Opening volume failed.\n";
		return false;
	}
	cout << "Opening volume completed.\n";
	
	
	BYTE* buff = (BYTE*)VirtualAlloc(NULL,gbuffsize,MEM_COMMIT | MEM_RESERVE,PAGE_EXECUTE_READWRITE);
	cout << "Reading volume .\n";
	ReadVolume(buff,gbuffsize);
	cout << "Reading volume completed.\n";

	return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
	gvolumehandle = INVALID_HANDLE_VALUE;
	wstring sourcevolume;
	cout << "Please enter source volume. (only name of volume single char) ";
	wcin >> sourcevolume;	

	BOOL prv = EnableBackupPrivileges();

	ReadVolume(sourcevolume);
	return 0;
}

Answer 1

I fixed the error.

 The main reason to get this error was invalid path. I was opening the volume where volume name was ended with \e.g c:\.

This opens file system on volume not volume itself(create file does not return error if u end volume name with \). Changing volume name fixed the problem