diff options
Diffstat (limited to 'Core/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c')
| -rw-r--r-- | Core/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/Core/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c b/Core/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c new file mode 100644 index 0000000000..4b0159c4fa --- /dev/null +++ b/Core/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c @@ -0,0 +1,331 @@ +/** @file
+ 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 - BIOS 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.
+
+Copyright (c) 2014, Hewlett-Packard Development Company, L.P.<BR>
+Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
+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.
+
+**/
+
+#include "Partition.h"
+
+/**
+ Test to see if the Mbr buffer is a valid MBR.
+
+ @param Mbr Parent Handle.
+ @param LastLba Last Lba address on the device.
+
+ @retval TRUE Mbr is a Valid MBR.
+ @retval FALSE Mbr is not a Valid MBR.
+
+**/
+BOOLEAN
+PartitionValidMbr (
+ IN MASTER_BOOT_RECORD *Mbr,
+ IN EFI_LBA LastLba
+ )
+{
+ 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
+ //
+
+ DEBUG((EFI_D_INFO, "PartitionValidMbr: Bad MBR partition size EndingLBA(%1x) > LastLBA(%1x)\n", EndingLBA, LastLba));
+
+ 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;
+ }
+ }
+ }
+ //
+ // None of the regions overlapped so MBR is O.K.
+ //
+ return MbrValid;
+}
+
+
+/**
+ Install child handles if the Handle supports MBR format.
+
+ @param[in] This Calling context.
+ @param[in] Handle Parent Handle.
+ @param[in] DiskIo Parent DiskIo interface.
+ @param[in] DiskIo2 Parent DiskIo2 interface.
+ @param[in] BlockIo Parent BlockIo interface.
+ @param[in] BlockIo2 Parent BlockIo2 interface.
+ @param[in] DevicePath Parent Device Path.
+
+ @retval EFI_SUCCESS A child handle was added.
+ @retval EFI_MEDIA_CHANGED Media change was detected.
+ @retval Others MBR partition was not found.
+
+**/
+EFI_STATUS
+PartitionInstallMbrChildHandles (
+ IN EFI_DRIVER_BINDING_PROTOCOL *This,
+ IN EFI_HANDLE Handle,
+ IN EFI_DISK_IO_PROTOCOL *DiskIo,
+ IN EFI_DISK_IO2_PROTOCOL *DiskIo2,
+ IN EFI_BLOCK_IO_PROTOCOL *BlockIo,
+ IN EFI_BLOCK_IO2_PROTOCOL *BlockIo2,
+ IN EFI_DEVICE_PATH_PROTOCOL *DevicePath
+ )
+{
+ 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;
+ UINT32 BlockSize;
+ UINT32 MediaId;
+ EFI_LBA LastBlock;
+
+ Found = EFI_NOT_FOUND;
+
+ BlockSize = BlockIo->Media->BlockSize;
+ MediaId = BlockIo->Media->MediaId;
+ LastBlock = BlockIo->Media->LastBlock;
+
+ Mbr = AllocatePool (BlockSize);
+ if (Mbr == NULL) {
+ return Found;
+ }
+
+ Status = DiskIo->ReadDisk (
+ DiskIo,
+ MediaId,
+ 0,
+ BlockSize,
+ Mbr
+ );
+ if (EFI_ERROR (Status)) {
+ Found = Status;
+ goto Done;
+ }
+ if (!PartitionValidMbr (Mbr, 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 (!IsDevicePathEnd (DevicePathNode)) {
+ LastDevicePathNode = DevicePathNode;
+ DevicePathNode = NextDevicePathNode (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 (Mbr->UniqueMbrSignature));
+
+ Status = PartitionInstallChildHandle (
+ This,
+ Handle,
+ DiskIo,
+ DiskIo2,
+ BlockIo,
+ BlockIo2,
+ 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 = DiskIo->ReadDisk (
+ DiskIo,
+ MediaId,
+ MultU64x32 (ExtMbrStartingLba, BlockSize),
+ BlockSize,
+ Mbr
+ );
+ if (EFI_ERROR (Status)) {
+ Found = Status;
+ goto Done;
+ }
+
+ if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 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,
+ DiskIo2,
+ BlockIo,
+ BlockIo2,
+ 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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