| 1 | /* $Id: Mbr.c 42653 2012-08-07 10:32:00Z vboxsync $ */
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| 2 | /** @file
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| 3 | * Mbr.c
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2012 Oracle Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | */
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| 17 |
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| 18 | /** @file
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| 19 | Decode a hard disk partitioned with the legacy MBR found on most PC's
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| 20 |
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| 21 | MBR - Master Boot Record is in the first sector of a partitioned hard disk.
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| 22 | The MBR supports four partitions per disk. The MBR also contains legacy
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| 23 | code that is not run on an EFI system. The legacy code reads the
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| 24 | first sector of the active partition into memory and
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| 25 |
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| 26 | BPB - BIOS Parameter Block is in the first sector of a FAT file system.
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| 27 | The BPB contains information about the FAT file system. The BPB is
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| 28 | always on the first sector of a media. The first sector also contains
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| 29 | the legacy boot strap code.
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| 30 |
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| 31 | Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
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| 32 | This program and the accompanying materials
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| 33 | are licensed and made available under the terms and conditions of the BSD License
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| 34 | which accompanies this distribution. The full text of the license may be found at
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| 35 | http://opensource.org/licenses/bsd-license.php
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| 36 |
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| 37 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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| 38 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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| 39 |
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| 40 | **/
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| 41 |
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| 42 | #include "Partition.h"
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| 43 |
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| 44 | /**
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| 45 | Test to see if the Mbr buffer is a valid MBR.
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| 46 |
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| 47 | @param Mbr Parent Handle.
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| 48 | @param LastLba Last Lba address on the device.
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| 49 |
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| 50 | @retval TRUE Mbr is a Valid MBR.
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| 51 | @retval FALSE Mbr is not a Valid MBR.
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| 52 |
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| 53 | **/
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| 54 | BOOLEAN
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| 55 | PartitionValidMbr (
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| 56 | IN MASTER_BOOT_RECORD *Mbr,
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| 57 | IN EFI_LBA LastLba
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| 58 | )
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| 59 | {
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| 60 | UINT32 StartingLBA;
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| 61 | UINT32 EndingLBA;
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| 62 | UINT32 NewEndingLBA;
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| 63 | INTN Index1;
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| 64 | INTN Index2;
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| 65 | BOOLEAN MbrValid;
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| 66 |
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| 67 | if (Mbr->Signature != MBR_SIGNATURE) {
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| 68 | return FALSE;
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| 69 | }
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| 70 | //
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| 71 | // The BPB also has this signature, so it can not be used alone.
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| 72 | //
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| 73 | MbrValid = FALSE;
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| 74 | for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {
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| 75 | if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {
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| 76 | continue;
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| 77 | }
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| 78 |
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| 79 | MbrValid = TRUE;
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| 80 | StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
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| 81 | EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;
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| 82 | if (EndingLBA > LastLba) {
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| 83 | //
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| 84 | // Compatibility Errata:
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| 85 | // Some systems try to hide drive space with their INT 13h driver
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| 86 | // This does not hide space from the OS driver. This means the MBR
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| 87 | // that gets created from DOS is smaller than the MBR created from
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| 88 | // a real OS (NT & Win98). This leads to BlockIo->LastBlock being
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| 89 | // wrong on some systems FDISKed by the OS.
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| 90 | //
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| 91 | // return FALSE since no block devices on a system are implemented
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| 92 | // with INT 13h
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| 93 | //
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| 94 | return FALSE;
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| 95 | }
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| 96 |
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| 97 | for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {
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| 98 | if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {
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| 99 | continue;
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| 100 | }
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| 101 |
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| 102 | NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;
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| 103 | if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {
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| 104 | //
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| 105 | // This region overlaps with the Index1'th region
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| 106 | //
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| 107 | return FALSE;
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| 108 | }
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| 109 | }
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| 110 | }
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| 111 | //
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| 112 | // None of the regions overlapped so MBR is O.K.
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| 113 | //
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| 114 | return MbrValid;
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| 115 | }
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| 116 |
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| 117 |
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| 118 | /**
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| 119 | Install child handles if the Handle supports MBR format.
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| 120 |
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| 121 | @param[in] This Calling context.
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| 122 | @param[in] Handle Parent Handle.
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| 123 | @param[in] DiskIo Parent DiskIo interface.
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| 124 | @param[in] BlockIo Parent BlockIo interface.
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| 125 | @param[in] BlockIo2 Parent BlockIo2 interface.
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| 126 | @param[in] DevicePath Parent Device Path.
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| 127 |
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| 128 | @retval EFI_SUCCESS A child handle was added.
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| 129 | @retval EFI_MEDIA_CHANGED Media change was detected.
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| 130 | @retval Others MBR partition was not found.
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| 131 |
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| 132 | **/
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| 133 | EFI_STATUS
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| 134 | PartitionInstallMbrChildHandles (
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| 135 | IN EFI_DRIVER_BINDING_PROTOCOL *This,
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| 136 | IN EFI_HANDLE Handle,
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| 137 | IN EFI_DISK_IO_PROTOCOL *DiskIo,
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| 138 | IN EFI_BLOCK_IO_PROTOCOL *BlockIo,
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| 139 | IN EFI_BLOCK_IO2_PROTOCOL *BlockIo2,
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| 140 | IN EFI_DEVICE_PATH_PROTOCOL *DevicePath
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| 141 | )
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| 142 | {
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| 143 | EFI_STATUS Status;
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| 144 | MASTER_BOOT_RECORD *Mbr;
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| 145 | UINT32 ExtMbrStartingLba;
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| 146 | UINTN Index;
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| 147 | HARDDRIVE_DEVICE_PATH HdDev;
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| 148 | HARDDRIVE_DEVICE_PATH ParentHdDev;
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| 149 | EFI_STATUS Found;
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| 150 | UINT32 PartitionNumber;
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| 151 | EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;
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| 152 | EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;
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| 153 | UINT32 BlockSize;
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| 154 | UINT32 MediaId;
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| 155 | EFI_LBA LastBlock;
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| 156 |
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| 157 | Found = EFI_NOT_FOUND;
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| 158 |
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| 159 | BlockSize = BlockIo->Media->BlockSize;
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| 160 | MediaId = BlockIo->Media->MediaId;
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| 161 | LastBlock = BlockIo->Media->LastBlock;
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| 162 |
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| 163 | LogFlowFuncMarkDP(DevicePath);
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| 164 | Mbr = AllocatePool (BlockSize);
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| 165 | if (Mbr == NULL) {
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| 166 | return Found;
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| 167 | }
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| 168 |
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| 169 | Status = DiskIo->ReadDisk (
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| 170 | DiskIo,
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| 171 | MediaId,
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| 172 | 0,
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| 173 | BlockSize,
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| 174 | Mbr
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| 175 | );
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| 176 | if (EFI_ERROR (Status)) {
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| 177 | Found = Status;
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| 178 | goto Done;
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| 179 | }
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| 180 | if (!PartitionValidMbr (Mbr, LastBlock)) {
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| 181 | goto Done;
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| 182 | }
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| 183 | //
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| 184 | // We have a valid mbr - add each partition
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| 185 | //
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| 186 | //
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| 187 | // Get starting and ending LBA of the parent block device.
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| 188 | //
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| 189 | LastDevicePathNode = NULL;
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| 190 | ZeroMem (&ParentHdDev, sizeof (ParentHdDev));
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| 191 | DevicePathNode = DevicePath;
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| 192 | while (!IsDevicePathEnd (DevicePathNode)) {
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| 193 | LastDevicePathNode = DevicePathNode;
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| 194 | DevicePathNode = NextDevicePathNode (DevicePathNode);
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| 195 | }
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| 196 |
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| 197 | if (LastDevicePathNode != NULL) {
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| 198 | if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&
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| 199 | DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP
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| 200 | ) {
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| 201 | CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));
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| 202 | } else {
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| 203 | LastDevicePathNode = NULL;
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| 204 | }
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| 205 | }
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| 206 |
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| 207 | PartitionNumber = 1;
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| 208 |
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| 209 | ZeroMem (&HdDev, sizeof (HdDev));
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| 210 | HdDev.Header.Type = MEDIA_DEVICE_PATH;
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| 211 | HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;
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| 212 | SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));
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| 213 | HdDev.MBRType = MBR_TYPE_PCAT;
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| 214 | HdDev.SignatureType = SIGNATURE_TYPE_MBR;
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| 215 |
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| 216 | if (LastDevicePathNode == NULL) {
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| 217 | //
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| 218 | // This is a MBR, add each partition
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| 219 | //
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| 220 | for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
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| 221 | if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {
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| 222 | //
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| 223 | // Don't use null MBR entries
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| 224 | //
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| 225 | continue;
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| 226 | }
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| 227 |
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| 228 | if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {
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| 229 | //
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| 230 | // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.
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| 231 | // We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating
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| 232 | // this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format
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| 233 | // that corrupted the GPT partition.
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| 234 | //
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| 235 | continue;
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| 236 | }
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| 237 |
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| 238 | HdDev.PartitionNumber = PartitionNumber ++;
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| 239 | HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);
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| 240 | HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);
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| 241 | CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (Mbr->UniqueMbrSignature));
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| 242 |
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| 243 | Status = PartitionInstallChildHandle (
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| 244 | This,
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| 245 | Handle,
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| 246 | DiskIo,
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| 247 | BlockIo,
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| 248 | BlockIo2,
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| 249 | DevicePath,
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| 250 | (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
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| 251 | HdDev.PartitionStart,
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| 252 | HdDev.PartitionStart + HdDev.PartitionSize - 1,
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| 253 | MBR_SIZE,
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| 254 | (BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)
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| 255 | );
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| 256 |
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| 257 | if (!EFI_ERROR (Status)) {
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| 258 | Found = EFI_SUCCESS;
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| 259 | }
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| 260 | }
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| 261 | } else {
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| 262 | //
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| 263 | // It's an extended partition. Follow the extended partition
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| 264 | // chain to get all the logical drives
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| 265 | //
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| 266 | ExtMbrStartingLba = 0;
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| 267 |
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| 268 | do {
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| 269 |
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| 270 | Status = DiskIo->ReadDisk (
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| 271 | DiskIo,
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| 272 | MediaId,
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| 273 | MultU64x32 (ExtMbrStartingLba, BlockSize),
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| 274 | BlockSize,
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| 275 | Mbr
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| 276 | );
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| 277 | if (EFI_ERROR (Status)) {
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| 278 | Found = Status;
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| 279 | goto Done;
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| 280 | }
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| 281 |
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| 282 | if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {
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| 283 | break;
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| 284 | }
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| 285 |
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| 286 | if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||
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| 287 | (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {
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| 288 | ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);
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| 289 | continue;
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| 290 | }
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| 291 | HdDev.PartitionNumber = PartitionNumber ++;
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| 292 | HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;
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| 293 | HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);
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| 294 | if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||
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| 295 | (HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {
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| 296 | break;
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| 297 | }
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| 298 |
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| 299 | //
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| 300 | // The signature in EBR(Extended Boot Record) should always be 0.
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| 301 | //
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| 302 | *((UINT32 *) &HdDev.Signature[0]) = 0;
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| 303 |
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| 304 | Status = PartitionInstallChildHandle (
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| 305 | This,
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| 306 | Handle,
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| 307 | DiskIo,
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| 308 | BlockIo,
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| 309 | BlockIo2,
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| 310 | DevicePath,
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| 311 | (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
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| 312 | HdDev.PartitionStart - ParentHdDev.PartitionStart,
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| 313 | HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,
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| 314 | MBR_SIZE,
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| 315 | (BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)
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| 316 | );
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| 317 | if (!EFI_ERROR (Status)) {
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| 318 | Found = EFI_SUCCESS;
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| 319 | }
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| 320 |
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| 321 | if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&
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| 322 | (Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)
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| 323 | ) {
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| 324 | break;
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| 325 | }
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| 326 |
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| 327 | ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);
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| 328 | //
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| 329 | // Don't allow partition to be self referencing
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| 330 | //
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| 331 | if (ExtMbrStartingLba == 0) {
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| 332 | break;
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| 333 | }
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| 334 | } while (ExtMbrStartingLba < ParentHdDev.PartitionSize);
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| 335 | }
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| 336 |
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| 337 | Done:
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| 338 | FreePool (Mbr);
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| 339 |
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| 340 | return Found;
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| 341 | }
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