104 lines
4.0 KiB
C#
104 lines
4.0 KiB
C#
// ----------------------------------------------------------------------------
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ----------------------------------------------------------------------------
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namespace BootsectorUtils
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{
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using System;
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using System.IO;
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/// <summary>
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/// VpcFixedDiskInstaller
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/// Console utility to install a bootsector onto a VirtualPC FIXED hard disk partition
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/// </summary>
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class VpcFixedDiskInstaller
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{
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[STAThread]
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static void Main(string[] args)
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{
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try {
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if (args.Length != 3)
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throw new Exception("Error: The correct argument format is <VHD Name> <Boot Sector File> <partition>");
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VpcFixedDiskInstaller i = new VpcFixedDiskInstaller();
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i.Install(args[0], args[1], Convert.ToInt32(args[2]));
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}
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catch (Exception e) {
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Console.WriteLine(e.Message);
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}
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}
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public void Install(string VHDName, string BSName, int whichPartition)
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{
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FileStream HDFile, BSFile, BKFile;
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int size = 512;
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int skipsize;
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byte [] buffer = new Byte[size];
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byte [] oldBootSector = new Byte[size];
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byte [] newBootSector = new Byte[size];
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int bytesread;
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int MBRIndex = 446;
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int LBA;
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string backupFilename = "backup" + System.DateTime.Now.Ticks.ToString() + ".bootsector";
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Console.WriteLine("Setting bootsector of disk {0} in HD {1} to contents of file {2} and backing up old bootsector to {3}",
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whichPartition, VHDName, BSName, backupFilename);
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if (whichPartition > 3 || whichPartition < 0) {
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throw new Exception("Error: You must choose a partition between 0 and 3.");
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}
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HDFile = File.Open(VHDName, FileMode.Open, FileAccess.ReadWrite);
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// read the MBR from the VPC HDD file
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bytesread=HDFile.Read(buffer, 0, size);
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// branch based on partition type
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MBRIndex += ((16*whichPartition)+4);
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if ((buffer[MBRIndex] != 0x0c) && (buffer[MBRIndex] != 0x0e)) {
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throw new Exception("The partition you selected is not FAT32 type 0c or 0e.");
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}
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LBA = (int) buffer[MBRIndex+7];
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LBA = LBA*8 + buffer[MBRIndex+6];
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LBA = LBA*8 + buffer[MBRIndex+5];
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LBA = LBA*8 + buffer[MBRIndex+4];
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// now that we know the location of the boot sector, let's grab it...
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HDFile.Seek((LBA)*size, SeekOrigin.Begin);
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HDFile.Read(oldBootSector, 0, size);
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// read the new BootSector
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BSFile = File.Open(BSName, FileMode.Open, FileAccess.Read);
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bytesread = BSFile.Read(newBootSector,0,size);
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if (bytesread != size) {
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throw new Exception("Error: The boot sector is not big enough.");
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}
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if (newBootSector[510] != 0x55 || newBootSector[511] != 0xAA) {
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throw new Exception("Error: The boot sector file has an invalid signature.");
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}
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BSFile.Close();
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skipsize = newBootSector[1]+2;
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// save the old boot sector:
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BKFile = File.OpenWrite(backupFilename);
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BKFile.Write(oldBootSector, 0, size);
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BKFile.Close();
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// generate the new boot sector by copying the BPB and FAT parameters...
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for (int i = 3; i < skipsize; i++) {
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newBootSector[i] = oldBootSector[i];
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}
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// point of no return:
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// write the new boot sector:
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HDFile.Seek((LBA)*size, SeekOrigin.Begin);
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HDFile.Write(newBootSector, 0, size);
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HDFile.Close();
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}
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}
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}
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