mirror of https://github.com/acidanthera/audk.git
313 lines
10 KiB
C
313 lines
10 KiB
C
/** @file
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Decode a hard disk partitioned with the legacy MBR found on most PC's
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MBR - Master Boot Record is in the first sector of a partitioned hard disk.
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The MBR supports four partitions per disk. The MBR also contains legacy
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code that is not run on an EFI system. The legacy code reads the
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first sector of the active partition into memory and
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BPB - BIOS Parameter Block is in the first sector of a FAT file system.
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The BPB contains information about the FAT file system. The BPB is
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always on the first sector of a media. The first sector also contains
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the legacy boot strap code.
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Copyright (c) 2006 - 2008, Intel Corporation. <BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "Partition.h"
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/**
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Test to see if the Mbr buffer is a valid MBR.
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@param Mbr Parent Handle.
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@param LastLba Last Lba address on the device.
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@retval TRUE Mbr is a Valid MBR.
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@retval FALSE Mbr is not a Valid MBR.
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**/
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BOOLEAN
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PartitionValidMbr (
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IN MASTER_BOOT_RECORD *Mbr,
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IN EFI_LBA LastLba
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)
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{
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UINT32 StartingLBA;
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UINT32 EndingLBA;
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UINT32 NewEndingLBA;
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INTN Index1;
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INTN Index2;
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BOOLEAN MbrValid;
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if (Mbr->Signature != MBR_SIGNATURE) {
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return FALSE;
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}
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//
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// The BPB also has this signature, so it can not be used alone.
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//
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MbrValid = FALSE;
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for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {
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if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {
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continue;
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}
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MbrValid = TRUE;
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StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
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EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;
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if (EndingLBA > LastLba) {
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//
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// Compatibility Errata:
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// Some systems try to hide drive space with their INT 13h driver
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// This does not hide space from the OS driver. This means the MBR
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// that gets created from DOS is smaller than the MBR created from
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// a real OS (NT & Win98). This leads to BlockIo->LastBlock being
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// wrong on some systems FDISKed by the OS.
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//
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// return FALSE since no block devices on a system are implemented
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// with INT 13h
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//
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return FALSE;
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}
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for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {
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if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {
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continue;
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}
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NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;
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if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {
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//
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// This region overlaps with the Index1'th region
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//
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return FALSE;
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}
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}
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}
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//
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// None of the regions overlapped so MBR is O.K.
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//
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return MbrValid;
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}
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/**
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Install child handles if the Handle supports MBR format.
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@param This Calling context.
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@param Handle Parent Handle.
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@param DiskIo Parent DiskIo interface.
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@param BlockIo Parent BlockIo interface.
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@param DevicePath Parent Device Path.
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@retval EFI_SUCCESS A child handle was added.
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@retval EFI_MEDIA_CHANGED Media change was detected.
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@retval Others MBR partition was not found.
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**/
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EFI_STATUS
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PartitionInstallMbrChildHandles (
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IN EFI_DRIVER_BINDING_PROTOCOL *This,
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IN EFI_HANDLE Handle,
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IN EFI_DISK_IO_PROTOCOL *DiskIo,
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IN EFI_BLOCK_IO_PROTOCOL *BlockIo,
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IN EFI_DEVICE_PATH_PROTOCOL *DevicePath
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)
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{
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EFI_STATUS Status;
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MASTER_BOOT_RECORD *Mbr;
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UINT32 ExtMbrStartingLba;
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UINTN Index;
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HARDDRIVE_DEVICE_PATH HdDev;
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HARDDRIVE_DEVICE_PATH ParentHdDev;
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EFI_STATUS Found;
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UINT32 PartitionNumber;
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EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;
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EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;
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Found = EFI_NOT_FOUND;
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Mbr = AllocatePool (BlockIo->Media->BlockSize);
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if (Mbr == NULL) {
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goto Done;
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}
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Status = DiskIo->ReadDisk (
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DiskIo,
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BlockIo->Media->MediaId,
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0,
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BlockIo->Media->BlockSize,
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Mbr
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);
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if (EFI_ERROR (Status)) {
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Found = Status;
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goto Done;
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}
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if (!PartitionValidMbr (Mbr, BlockIo->Media->LastBlock)) {
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goto Done;
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}
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//
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// We have a valid mbr - add each partition
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//
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//
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// Get starting and ending LBA of the parent block device.
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//
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LastDevicePathNode = NULL;
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ZeroMem (&ParentHdDev, sizeof (ParentHdDev));
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DevicePathNode = DevicePath;
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while (!IsDevicePathEnd (DevicePathNode)) {
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LastDevicePathNode = DevicePathNode;
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DevicePathNode = NextDevicePathNode (DevicePathNode);
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}
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if (LastDevicePathNode != NULL) {
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if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&
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DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP
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) {
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CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));
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} else {
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LastDevicePathNode = NULL;
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}
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}
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PartitionNumber = 1;
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ZeroMem (&HdDev, sizeof (HdDev));
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HdDev.Header.Type = MEDIA_DEVICE_PATH;
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HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;
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SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));
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HdDev.MBRType = MBR_TYPE_PCAT;
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HdDev.SignatureType = SIGNATURE_TYPE_MBR;
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if (LastDevicePathNode == NULL) {
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//
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// This is a MBR, add each partition
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//
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for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
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if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {
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//
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// Don't use null MBR entries
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//
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continue;
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}
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if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {
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//
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// 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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// We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating
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// this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format
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// that corrupted the GPT partition.
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//
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continue;
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}
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HdDev.PartitionNumber = PartitionNumber ++;
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HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);
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HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);
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CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (Mbr->UniqueMbrSignature));
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Status = PartitionInstallChildHandle (
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This,
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Handle,
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DiskIo,
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BlockIo,
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DevicePath,
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(EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
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HdDev.PartitionStart,
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HdDev.PartitionStart + HdDev.PartitionSize - 1,
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MBR_SIZE,
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(BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)
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);
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if (!EFI_ERROR (Status)) {
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Found = EFI_SUCCESS;
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}
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}
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} else {
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//
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// It's an extended partition. Follow the extended partition
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// chain to get all the logical drives
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//
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ExtMbrStartingLba = 0;
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do {
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Status = DiskIo->ReadDisk (
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DiskIo,
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BlockIo->Media->MediaId,
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MultU64x32 (ExtMbrStartingLba, BlockIo->Media->BlockSize),
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BlockIo->Media->BlockSize,
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Mbr
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);
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if (EFI_ERROR (Status)) {
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Found = Status;
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goto Done;
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}
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if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {
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break;
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}
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if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||
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(Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {
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ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);
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continue;
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}
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HdDev.PartitionNumber = PartitionNumber ++;
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HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;
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HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);
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if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||
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(HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {
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break;
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}
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//
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// The signature in EBR(Extended Boot Record) should always be 0.
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//
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*((UINT32 *) &HdDev.Signature[0]) = 0;
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Status = PartitionInstallChildHandle (
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This,
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Handle,
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DiskIo,
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BlockIo,
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DevicePath,
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(EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
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HdDev.PartitionStart - ParentHdDev.PartitionStart,
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HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,
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MBR_SIZE,
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(BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)
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);
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if (!EFI_ERROR (Status)) {
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Found = EFI_SUCCESS;
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}
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if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&
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(Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)
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) {
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break;
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}
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ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);
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//
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// Don't allow partition to be self referencing
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//
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if (ExtMbrStartingLba == 0) {
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break;
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}
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} while (ExtMbrStartingLba < ParentHdDev.PartitionSize);
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}
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Done:
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FreePool (Mbr);
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return Found;
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}
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