diff options
Diffstat (limited to 'MdeModulePkg/Universal/Disk/Partition/Dxe/Mbr.c')
| -rw-r--r-- | MdeModulePkg/Universal/Disk/Partition/Dxe/Mbr.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/MdeModulePkg/Universal/Disk/Partition/Dxe/Mbr.c b/MdeModulePkg/Universal/Disk/Partition/Dxe/Mbr.c new file mode 100644 index 0000000000..bc08963e54 --- /dev/null +++ b/MdeModulePkg/Universal/Disk/Partition/Dxe/Mbr.c @@ -0,0 +1,333 @@ +/*++
+
+Copyright (c) 2006 - 2007, Intel Corporation
+All rights reserved. This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution. The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+Module Name:
+
+ Mbr.c
+
+Abstract:
+
+ Decode a hard disk partitioned with the legacy MBR found on most PC's
+
+ MBR - Master Boot Record is in the first sector of a partitioned hard disk.
+ The MBR supports four partitions per disk. The MBR also contains legacy
+ code that is not run on an EFI system. The legacy code reads the
+ first sector of the active partition into memory and
+
+ BPB - Boot(?) Parameter Block is in the first sector of a FAT file system.
+ The BPB contains information about the FAT file system. The BPB is
+ always on the first sector of a media. The first sector also contains
+ the legacy boot strap code.
+
+--*/
+
+//
+// Include common header file for this module.
+//
+#include "CommonHeader.h"
+
+#include "Partition.h"
+
+STATIC
+BOOLEAN
+PartitionValidMbr (
+ IN MASTER_BOOT_RECORD *Mbr,
+ IN EFI_LBA LastLba
+ )
+/*++
+
+Routine Description:
+ Test to see if the Mbr buffer is a valid MBR
+
+Arguments:
+ Mbr - Parent Handle
+ LastLba - Last Lba address on the device.
+
+Returns:
+ TRUE - Mbr is a Valid MBR
+ FALSE - Mbr is not a Valid MBR
+
+--*/
+{
+ UINT32 StartingLBA;
+ UINT32 EndingLBA;
+ UINT32 NewEndingLBA;
+ INTN Index1;
+ INTN Index2;
+ BOOLEAN MbrValid;
+
+ if (Mbr->Signature != MBR_SIGNATURE) {
+ return FALSE;
+ }
+ //
+ // The BPB also has this signature, so it can not be used alone.
+ //
+ MbrValid = FALSE;
+ for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {
+ if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {
+ continue;
+ }
+
+ MbrValid = TRUE;
+ StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
+ EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;
+ if (EndingLBA > LastLba) {
+ //
+ // Compatibility Errata:
+ // Some systems try to hide drive space with their INT 13h driver
+ // This does not hide space from the OS driver. This means the MBR
+ // that gets created from DOS is smaller than the MBR created from
+ // a real OS (NT & Win98). This leads to BlockIo->LastBlock being
+ // wrong on some systems FDISKed by the OS.
+ //
+ // return FALSE since no block devices on a system are implemented
+ // with INT 13h
+ //
+ return FALSE;
+ }
+
+ for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {
+ if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {
+ continue;
+ }
+
+ NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;
+ if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {
+ //
+ // This region overlaps with the Index1'th region
+ //
+ return FALSE;
+ }
+ }
+ }
+ //
+ // Non of the regions overlapped so MBR is O.K.
+ //
+ return MbrValid;
+}
+
+EFI_STATUS
+PartitionInstallMbrChildHandles (
+ IN EFI_DRIVER_BINDING_PROTOCOL *This,
+ IN EFI_HANDLE Handle,
+ IN EFI_DISK_IO_PROTOCOL *DiskIo,
+ IN EFI_BLOCK_IO_PROTOCOL *BlockIo,
+ IN EFI_DEVICE_PATH_PROTOCOL *DevicePath
+ )
+/*++
+
+Routine Description:
+ Install child handles if the Handle supports MBR format.
+
+Arguments:
+ This - Calling context.
+ Handle - Parent Handle
+ DiskIo - Parent DiskIo interface
+ BlockIo - Parent BlockIo interface
+ DevicePath - Parent Device Path
+
+Returns:
+ EFI_SUCCESS - If a child handle was added
+ EFI_MEDIA_CHANGED - Media changed Detected
+ !EFI_SUCCESS - Not found MBR partition.
+
+--*/
+{
+ EFI_STATUS Status;
+ MASTER_BOOT_RECORD *Mbr;
+ UINT32 ExtMbrStartingLba;
+ UINTN Index;
+ HARDDRIVE_DEVICE_PATH HdDev;
+ HARDDRIVE_DEVICE_PATH ParentHdDev;
+ EFI_STATUS Found;
+ UINT32 PartitionNumber;
+ EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;
+ EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;
+
+ Mbr = NULL;
+ Found = EFI_NOT_FOUND;
+
+ Mbr = AllocatePool (BlockIo->Media->BlockSize);
+ if (Mbr == NULL) {
+ goto Done;
+ }
+
+ Status = BlockIo->ReadBlocks (
+ BlockIo,
+ BlockIo->Media->MediaId,
+ 0,
+ BlockIo->Media->BlockSize,
+ Mbr
+ );
+ if (EFI_ERROR (Status)) {
+ Found = Status;
+ goto Done;
+ }
+ if (!PartitionValidMbr (Mbr, BlockIo->Media->LastBlock)) {
+ goto Done;
+ }
+ //
+ // We have a valid mbr - add each partition
+ //
+ //
+ // Get starting and ending LBA of the parent block device.
+ //
+ LastDevicePathNode = NULL;
+ ZeroMem (&ParentHdDev, sizeof (ParentHdDev));
+ DevicePathNode = DevicePath;
+ while (!EfiIsDevicePathEnd (DevicePathNode)) {
+ LastDevicePathNode = DevicePathNode;
+ DevicePathNode = EfiNextDevicePathNode (DevicePathNode);
+ }
+
+ if (LastDevicePathNode != NULL) {
+ if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&
+ DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP
+ ) {
+ CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));
+ } else {
+ LastDevicePathNode = NULL;
+ }
+ }
+
+ PartitionNumber = 1;
+
+ ZeroMem (&HdDev, sizeof (HdDev));
+ HdDev.Header.Type = MEDIA_DEVICE_PATH;
+ HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;
+ SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));
+ HdDev.MBRType = MBR_TYPE_PCAT;
+ HdDev.SignatureType = SIGNATURE_TYPE_MBR;
+
+ if (LastDevicePathNode == NULL) {
+ //
+ // This is a MBR, add each partition
+ //
+ for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {
+ if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {
+ //
+ // Don't use null MBR entries
+ //
+ continue;
+ }
+
+ if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {
+ //
+ // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.
+ // We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating
+ // this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format
+ // that corrupted the GPT partition.
+ //
+ continue;
+ }
+
+ HdDev.PartitionNumber = PartitionNumber ++;
+ HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);
+ HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);
+ CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (UINT32));
+
+ Status = PartitionInstallChildHandle (
+ This,
+ Handle,
+ DiskIo,
+ BlockIo,
+ DevicePath,
+ (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
+ HdDev.PartitionStart,
+ HdDev.PartitionStart + HdDev.PartitionSize - 1,
+ MBR_SIZE,
+ (BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)
+ );
+
+ if (!EFI_ERROR (Status)) {
+ Found = EFI_SUCCESS;
+ }
+ }
+ } else {
+ //
+ // It's an extended partition. Follow the extended partition
+ // chain to get all the logical drives
+ //
+ ExtMbrStartingLba = 0;
+
+ do {
+
+ Status = BlockIo->ReadBlocks (
+ BlockIo,
+ BlockIo->Media->MediaId,
+ ExtMbrStartingLba,
+ BlockIo->Media->BlockSize,
+ Mbr
+ );
+ if (EFI_ERROR (Status)) {
+ Found = Status;
+ goto Done;
+ }
+
+ if (Mbr->Partition[0].OSIndicator == 0) {
+ break;
+ }
+
+ if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||
+ (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {
+ ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);
+ continue;
+ }
+ HdDev.PartitionNumber = PartitionNumber ++;
+ HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;
+ HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);
+ if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||
+ (HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {
+ break;
+ }
+
+ //
+ // The signature in EBR(Extended Boot Record) should always be 0.
+ //
+ *((UINT32 *) &HdDev.Signature[0]) = 0;
+
+ Status = PartitionInstallChildHandle (
+ This,
+ Handle,
+ DiskIo,
+ BlockIo,
+ DevicePath,
+ (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,
+ HdDev.PartitionStart - ParentHdDev.PartitionStart,
+ HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,
+ MBR_SIZE,
+ (BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)
+ );
+ if (!EFI_ERROR (Status)) {
+ Found = EFI_SUCCESS;
+ }
+
+ if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&
+ (Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)
+ ) {
+ break;
+ }
+
+ ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);
+ //
+ // Don't allow partition to be self referencing
+ //
+ if (ExtMbrStartingLba == 0) {
+ break;
+ }
+ } while (ExtMbrStartingLba < ParentHdDev.PartitionSize);
+ }
+
+Done:
+ FreePool (Mbr);
+
+ return Found;
+}
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