3 Copyright (c) 2006, Intel Corporation
4 All rights reserved. This program and the accompanying materials
5 are licensed and made available under the terms and conditions of the BSD License
6 which accompanies this distribution. The full text of the license may be found at
7 http://opensource.org/licenses/bsd-license.php
9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
18 Decode a hard disk partitioned with the legacy MBR found on most PC's
20 MBR - Master Boot Record is in the first sector of a partitioned hard disk.
21 The MBR supports four partitions per disk. The MBR also contains legacy
22 code that is not run on an EFI system. The legacy code reads the
23 first sector of the active partition into memory and
25 BPB - Boot(?) Parameter Block is in the first sector of a FAT file system.
26 The BPB contains information about the FAT file system. The BPB is
27 always on the first sector of a media. The first sector also contains
28 the legacy boot strap code.
32 #include "Partition.h"
37 IN MASTER_BOOT_RECORD
*Mbr
,
43 Test to see if the Mbr buffer is a valid MBR
47 LastLba - Last Lba address on the device.
50 TRUE - Mbr is a Valid MBR
51 FALSE - Mbr is not a Valid MBR
62 if (Mbr
->Signature
!= MBR_SIGNATURE
) {
66 // The BPB also has this signature, so it can not be used alone.
69 for (Index1
= 0; Index1
< MAX_MBR_PARTITIONS
; Index1
++) {
70 if (Mbr
->Partition
[Index1
].OSIndicator
== 0x00 || UNPACK_UINT32 (Mbr
->Partition
[Index1
].SizeInLBA
) == 0) {
75 StartingLBA
= UNPACK_UINT32 (Mbr
->Partition
[Index1
].StartingLBA
);
76 EndingLBA
= StartingLBA
+ UNPACK_UINT32 (Mbr
->Partition
[Index1
].SizeInLBA
) - 1;
77 if (EndingLBA
> LastLba
) {
79 // Compatibility Errata:
80 // Some systems try to hide drive space with their INT 13h driver
81 // This does not hide space from the OS driver. This means the MBR
82 // that gets created from DOS is smaller than the MBR created from
83 // a real OS (NT & Win98). This leads to BlockIo->LastBlock being
84 // wrong on some systems FDISKed by the OS.
86 // return FALSE since no block devices on a system are implemented
92 for (Index2
= Index1
+ 1; Index2
< MAX_MBR_PARTITIONS
; Index2
++) {
93 if (Mbr
->Partition
[Index2
].OSIndicator
== 0x00 || UNPACK_UINT32 (Mbr
->Partition
[Index2
].SizeInLBA
) == 0) {
97 NewEndingLBA
= UNPACK_UINT32 (Mbr
->Partition
[Index2
].StartingLBA
) + UNPACK_UINT32 (Mbr
->Partition
[Index2
].SizeInLBA
) - 1;
98 if (NewEndingLBA
>= StartingLBA
&& UNPACK_UINT32 (Mbr
->Partition
[Index2
].StartingLBA
) <= EndingLBA
) {
100 // This region overlaps with the Index1'th region
107 // Non of the regions overlapped so MBR is O.K.
113 PartitionInstallMbrChildHandles (
114 IN EFI_DRIVER_BINDING_PROTOCOL
*This
,
115 IN EFI_HANDLE Handle
,
116 IN EFI_DISK_IO_PROTOCOL
*DiskIo
,
117 IN EFI_BLOCK_IO_PROTOCOL
*BlockIo
,
118 IN EFI_DEVICE_PATH_PROTOCOL
*DevicePath
123 Install child handles if the Handle supports MBR format.
126 This - Calling context.
127 Handle - Parent Handle
128 DiskIo - Parent DiskIo interface
129 BlockIo - Parent BlockIo interface
130 DevicePath - Parent Device Path
133 EFI_SUCCESS - If a child handle was added
134 other - A child handle was not added
139 MASTER_BOOT_RECORD
*Mbr
;
140 UINT32 ExtMbrStartingLba
;
142 HARDDRIVE_DEVICE_PATH HdDev
;
143 HARDDRIVE_DEVICE_PATH ParentHdDev
;
145 UINT32 PartitionNumber
;
146 EFI_DEVICE_PATH_PROTOCOL
*DevicePathNode
;
147 EFI_DEVICE_PATH_PROTOCOL
*LastDevicePathNode
;
152 Mbr
= AllocatePool (BlockIo
->Media
->BlockSize
);
157 Status
= BlockIo
->ReadBlocks (
159 BlockIo
->Media
->MediaId
,
161 BlockIo
->Media
->BlockSize
,
164 if (EFI_ERROR (Status
) || !PartitionValidMbr (Mbr
, BlockIo
->Media
->LastBlock
)) {
168 // We have a valid mbr - add each partition
171 // Get starting and ending LBA of the parent block device.
173 LastDevicePathNode
= NULL
;
174 ZeroMem (&ParentHdDev
, sizeof (ParentHdDev
));
175 DevicePathNode
= DevicePath
;
176 while (!EfiIsDevicePathEnd (DevicePathNode
)) {
177 LastDevicePathNode
= DevicePathNode
;
178 DevicePathNode
= EfiNextDevicePathNode (DevicePathNode
);
181 if (LastDevicePathNode
!= NULL
) {
182 if (DevicePathType (LastDevicePathNode
) == MEDIA_DEVICE_PATH
&&
183 DevicePathSubType (LastDevicePathNode
) == MEDIA_HARDDRIVE_DP
185 gBS
->CopyMem (&ParentHdDev
, LastDevicePathNode
, sizeof (ParentHdDev
));
187 LastDevicePathNode
= NULL
;
193 ZeroMem (&HdDev
, sizeof (HdDev
));
194 HdDev
.Header
.Type
= MEDIA_DEVICE_PATH
;
195 HdDev
.Header
.SubType
= MEDIA_HARDDRIVE_DP
;
196 SetDevicePathNodeLength (&HdDev
.Header
, sizeof (HdDev
));
197 HdDev
.MBRType
= MBR_TYPE_PCAT
;
198 HdDev
.SignatureType
= SIGNATURE_TYPE_MBR
;
200 if (LastDevicePathNode
== NULL
) {
202 // This is a MBR, add each partition
204 for (Index
= 0; Index
< MAX_MBR_PARTITIONS
; Index
++) {
205 if (Mbr
->Partition
[Index
].OSIndicator
== 0x00 || UNPACK_UINT32 (Mbr
->Partition
[Index
].SizeInLBA
) == 0) {
207 // Don't use null MBR entries
212 if (Mbr
->Partition
[Index
].OSIndicator
== 0xEE) {
214 // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.
215 // We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating
216 // this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format
217 // that corrupted the GPT partition.
222 HdDev
.PartitionNumber
= PartitionNumber
++;
223 HdDev
.PartitionStart
= UNPACK_UINT32 (Mbr
->Partition
[Index
].StartingLBA
);
224 HdDev
.PartitionSize
= UNPACK_UINT32 (Mbr
->Partition
[Index
].SizeInLBA
);
225 CopyMem (HdDev
.Signature
, &(Mbr
->UniqueMbrSignature
[0]), sizeof (UINT32
));
227 Status
= PartitionInstallChildHandle (
233 (EFI_DEVICE_PATH_PROTOCOL
*) &HdDev
,
234 HdDev
.PartitionStart
,
235 HdDev
.PartitionStart
+ HdDev
.PartitionSize
- 1,
237 (BOOLEAN
) (Mbr
->Partition
[Index
].OSIndicator
== EFI_PARTITION
)
240 if (!EFI_ERROR (Status
)) {
246 // It's an extended partition. Follow the extended partition
247 // chain to get all the logical drives
249 ExtMbrStartingLba
= 0;
253 Status
= BlockIo
->ReadBlocks (
255 BlockIo
->Media
->MediaId
,
257 BlockIo
->Media
->BlockSize
,
260 if (EFI_ERROR (Status
)) {
264 if (Mbr
->Partition
[0].OSIndicator
== 0) {
268 HdDev
.PartitionNumber
= PartitionNumber
++;
269 HdDev
.PartitionStart
= UNPACK_UINT32 (Mbr
->Partition
[0].StartingLBA
) + ExtMbrStartingLba
+ ParentHdDev
.PartitionStart
;
270 HdDev
.PartitionSize
= UNPACK_UINT32 (Mbr
->Partition
[0].SizeInLBA
);
271 if (HdDev
.PartitionStart
+ HdDev
.PartitionSize
- 1 >=
272 ParentHdDev
.PartitionStart
+ ParentHdDev
.PartitionSize
) {
277 // The signature in EBR(Extended Boot Record) should always be 0.
279 *((UINT32
*) &HdDev
.Signature
[0]) = 0;
281 Status
= PartitionInstallChildHandle (
287 (EFI_DEVICE_PATH_PROTOCOL
*) &HdDev
,
288 HdDev
.PartitionStart
- ParentHdDev
.PartitionStart
,
289 HdDev
.PartitionStart
- ParentHdDev
.PartitionStart
+ HdDev
.PartitionSize
- 1,
291 (BOOLEAN
) (Mbr
->Partition
[0].OSIndicator
== EFI_PARTITION
)
293 if (!EFI_ERROR (Status
)) {
297 if (Mbr
->Partition
[1].OSIndicator
!= EXTENDED_DOS_PARTITION
&&
298 Mbr
->Partition
[1].OSIndicator
!= EXTENDED_WINDOWS_PARTITION
303 ExtMbrStartingLba
= UNPACK_UINT32 (Mbr
->Partition
[1].StartingLBA
);
305 // Don't allow partition to be self referencing
307 if (ExtMbrStartingLba
== 0) {
310 } while (ExtMbrStartingLba
< ParentHdDev
.PartitionSize
);