win32_volume.c

/*
 *  FreeLoader - volume.c
 *
 *  Copyright (C) 2001  Brian Palmer  <brianp@sginet.com>
 *  Copyright (C) 2021  Arnav Bhatt   <arnavbhatt288@gmail.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

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

#include "win32_volume.h"

FileHandle* OpenVolume(LPCTSTR lpszVolumeName)
{
    TCHAR RealVolumeName[MAX_PATH];
    FileHandle* fhandle = GlobalAlloc(GPTR, sizeof(*fhandle));

    _tcscpy(RealVolumeName, _T("\\\\.\\"));
    _tcscat(RealVolumeName, lpszVolumeName);

    _tprintf(_T("Opening volume \'%s\'\n"), lpszVolumeName);

    fhandle->file = CreateFile(RealVolumeName,
                               GENERIC_READ | GENERIC_WRITE,
                               FILE_SHARE_READ | FILE_SHARE_WRITE,
                               NULL,
                               OPEN_EXISTING,
                               0,
                               NULL);

    if (fhandle->file == INVALID_HANDLE_VALUE)
    {
        _tprintf(_T("%s:%d: "), __FILE__, __LINE__);
        _tprintf(_T("Failed. Error code %ld.\n"), GetLastError());
        return NULL;
    }

    return fhandle;
}

void CloseVolume(FileHandle* fhandle)
{
    CloseHandle(fhandle->file);
    GlobalFree(fhandle);
}

BOOL ReadVolumeSector(FileHandle* fhandle, ULONG SectorNumber, PVOID SectorBuffer)
{
    DWORD    dwNumberOfBytesRead;
    DWORD    dwFilePosition;
    int    bRetVal;

    //
    // FIXME: this doesn't seem to handle the situation
    // properly when SectorNumber is bigger than the
    // amount of sectors on the disk. Seems to me that
    // the call to SetFilePointer() should just give an
    // out of bounds error or something but it doesn't.
    //
    dwFilePosition = SetFilePointer(fhandle->file, (SectorNumber * 512), NULL, FILE_BEGIN);
    if (dwFilePosition != (SectorNumber * 512))
    {
        _tprintf(_T("%s:%d: "), __FILE__, __LINE__);
        _tprintf(_T("SetFilePointer() failed. Error code %ld.\n"), GetLastError());
        return FALSE;
    }

    bRetVal = ReadFile(fhandle->file, SectorBuffer, 512, &dwNumberOfBytesRead, NULL);
    if (!bRetVal || (dwNumberOfBytesRead != 512))
    {
        _tprintf(_T("%s:%d: "), __FILE__, __LINE__);
        _tprintf(_T("ReadFile() failed. Error code %ld.\n"), GetLastError());
        return FALSE;
    }

    return TRUE;
}

BOOL WriteVolumeSector(FileHandle* fhandle, ULONG SectorNumber, PVOID SectorBuffer)
{
    DWORD    dwNumberOfBytesWritten;
    DWORD    dwFilePosition;
    int    bRetVal;

    //
    // FIXME: this doesn't seem to handle the situation
    // properly when SectorNumber is bigger than the
    // amount of sectors on the disk. Seems to me that
    // the call to SetFilePointer() should just give an
    // out of bounds error or something but it doesn't.
    //
    dwFilePosition = SetFilePointer(fhandle->file, (SectorNumber * 512), NULL, FILE_BEGIN);
    if (dwFilePosition != (SectorNumber * 512))
    {
        _tprintf(_T("%s:%d: "), __FILE__, __LINE__);
        _tprintf(_T("SetFilePointer() failed. Error code %ld.\n"), GetLastError());
        return FALSE;
    }

    bRetVal = WriteFile(fhandle->file, SectorBuffer, 512, &dwNumberOfBytesWritten, NULL);
    if (!bRetVal || (dwNumberOfBytesWritten != 512))
    {
        _tprintf(_T("%s:%d: "), __FILE__, __LINE__);
        _tprintf(_T("WriteFile() failed. Error code %ld.\n"), GetLastError());
        return FALSE;
    }

    return TRUE;
}