[mirror_edk2.git] / MdeModulePkg / Universal / Disk / PartitionDxe / Mbr.c

/** @file\r
  Decode a hard disk partitioned with the legacy MBR found on most PC's\r
\r
  MBR - Master Boot Record is in the first sector of a partitioned hard disk.\r
        The MBR supports four partitions per disk. The MBR also contains legacy\r
        code that is not run on an EFI system. The legacy code reads the \r
        first sector of the active partition into memory and \r
\r
  BPB - BIOS Parameter Block is in the first sector of a FAT file system. \r
        The BPB contains information about the FAT file system. The BPB is \r
        always on the first sector of a media. The first sector also contains\r
        the legacy boot strap code.\r
\r
Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
This program and the accompanying materials\r
are licensed and made available under the terms and conditions of the BSD License\r
which accompanies this distribution.  The full text of the license may be found at\r
http://opensource.org/licenses/bsd-license.php\r
\r
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "Partition.h"\r
\r
/**\r
  Test to see if the Mbr buffer is a valid MBR.\r
\r
  @param  Mbr         Parent Handle.\r
  @param  LastLba     Last Lba address on the device.\r
   \r
  @retval TRUE        Mbr is a Valid MBR.\r
  @retval FALSE       Mbr is not a Valid MBR.\r
\r
**/\r
BOOLEAN\r
PartitionValidMbr (\r
  IN  MASTER_BOOT_RECORD      *Mbr,\r
  IN  EFI_LBA                 LastLba\r
  )\r
{\r
  UINT32  StartingLBA;\r
  UINT32  EndingLBA;\r
  UINT32  NewEndingLBA;\r
  INTN    Index1;\r
  INTN    Index2;\r
  BOOLEAN MbrValid;\r
\r
  if (Mbr->Signature != MBR_SIGNATURE) {\r
    return FALSE;\r
  }\r
  //\r
  // The BPB also has this signature, so it can not be used alone.\r
  //\r
  MbrValid = FALSE;\r
  for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {\r
    if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {\r
      continue;\r
    }\r
\r
    MbrValid    = TRUE;\r
    StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);\r
    EndingLBA   = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;\r
    if (EndingLBA > LastLba) {\r
      //\r
      // Compatibility Errata:\r
      //  Some systems try to hide drive space with their INT 13h driver\r
      //  This does not hide space from the OS driver. This means the MBR\r
      //  that gets created from DOS is smaller than the MBR created from\r
      //  a real OS (NT & Win98). This leads to BlockIo->LastBlock being\r
      //  wrong on some systems FDISKed by the OS.\r
      //\r
      // return FALSE since no block devices on a system are implemented\r
      // with INT 13h\r
      //\r
      return FALSE;\r
    }\r
\r
    for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {\r
      if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {\r
        continue;\r
      }\r
\r
      NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;\r
      if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {\r
        //\r
        // This region overlaps with the Index1'th region\r
        //\r
        return FALSE;\r
      }\r
    }\r
  }\r
  //\r
  // None of the regions overlapped so MBR is O.K.\r
  //\r
  return MbrValid;\r
}\r
\r
\r
/**\r
  Install child handles if the Handle supports MBR format.\r
\r
  @param[in]  This              Calling context.\r
  @param[in]  Handle            Parent Handle.\r
  @param[in]  DiskIo            Parent DiskIo interface.\r
  @param[in]  DiskIo2           Parent DiskIo2 interface.\r
  @param[in]  BlockIo           Parent BlockIo interface.\r
  @param[in]  BlockIo2          Parent BlockIo2 interface.\r
  @param[in]  DevicePath        Parent Device Path.\r
   \r
  @retval EFI_SUCCESS       A child handle was added.\r
  @retval EFI_MEDIA_CHANGED Media change was detected.\r
  @retval Others            MBR partition was not found.\r
\r
**/\r
EFI_STATUS\r
PartitionInstallMbrChildHandles (\r
  IN  EFI_DRIVER_BINDING_PROTOCOL  *This,\r
  IN  EFI_HANDLE                   Handle,\r
  IN  EFI_DISK_IO_PROTOCOL         *DiskIo,\r
  IN  EFI_DISK_IO2_PROTOCOL        *DiskIo2,\r
  IN  EFI_BLOCK_IO_PROTOCOL        *BlockIo,\r
  IN  EFI_BLOCK_IO2_PROTOCOL       *BlockIo2,\r
  IN  EFI_DEVICE_PATH_PROTOCOL     *DevicePath\r
  )\r
{\r
  EFI_STATUS                Status;\r
  MASTER_BOOT_RECORD        *Mbr;\r
  UINT32                    ExtMbrStartingLba;\r
  UINTN                     Index;\r
  HARDDRIVE_DEVICE_PATH     HdDev;\r
  HARDDRIVE_DEVICE_PATH     ParentHdDev;\r
  EFI_STATUS                Found;\r
  UINT32                    PartitionNumber;\r
  EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode;\r
  EFI_DEVICE_PATH_PROTOCOL  *LastDevicePathNode;\r
  UINT32                    BlockSize;\r
  UINT32                    MediaId;\r
  EFI_LBA                   LastBlock;\r
\r
  Found           = EFI_NOT_FOUND;\r
\r
  BlockSize = BlockIo->Media->BlockSize;\r
  MediaId   = BlockIo->Media->MediaId;\r
  LastBlock = BlockIo->Media->LastBlock;\r
\r
  Mbr = AllocatePool (BlockSize);\r
  if (Mbr == NULL) {\r
    return Found;\r
  }\r
\r
  Status = DiskIo->ReadDisk (\r
                     DiskIo,\r
                     MediaId,\r
                     0,\r
                     BlockSize,\r
                     Mbr\r
                     );\r
  if (EFI_ERROR (Status)) {\r
    Found = Status;\r
    goto Done;\r
  }\r
  if (!PartitionValidMbr (Mbr, LastBlock)) {\r
    goto Done;\r
  }\r
  //\r
  // We have a valid mbr - add each partition\r
  //\r
  //\r
  // Get starting and ending LBA of the parent block device.\r
  //\r
  LastDevicePathNode = NULL;\r
  ZeroMem (&ParentHdDev, sizeof (ParentHdDev));\r
  DevicePathNode = DevicePath;\r
  while (!IsDevicePathEnd (DevicePathNode)) {\r
    LastDevicePathNode  = DevicePathNode;\r
    DevicePathNode      = NextDevicePathNode (DevicePathNode);\r
  }\r
\r
  if (LastDevicePathNode != NULL) {\r
    if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&\r
        DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP\r
        ) {\r
      CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));\r
    } else {\r
      LastDevicePathNode = NULL;\r
    }\r
  }\r
\r
  PartitionNumber = 1;\r
\r
  ZeroMem (&HdDev, sizeof (HdDev));\r
  HdDev.Header.Type     = MEDIA_DEVICE_PATH;\r
  HdDev.Header.SubType  = MEDIA_HARDDRIVE_DP;\r
  SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));\r
  HdDev.MBRType         = MBR_TYPE_PCAT;\r
  HdDev.SignatureType   = SIGNATURE_TYPE_MBR;\r
\r
  if (LastDevicePathNode == NULL) {\r
    //\r
    // This is a MBR, add each partition\r
    //\r
    for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {\r
      if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {\r
        //\r
        // Don't use null MBR entries\r
        //\r
        continue;\r
      }\r
\r
      if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {\r
        //\r
        // This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.\r
        //  We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating \r
        //  this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format\r
        //  that corrupted the GPT partition. \r
        //\r
        continue;\r
      }\r
\r
      HdDev.PartitionNumber = PartitionNumber ++;\r
      HdDev.PartitionStart  = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);\r
      HdDev.PartitionSize   = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);\r
      CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (Mbr->UniqueMbrSignature));\r
\r
      Status = PartitionInstallChildHandle (\r
                This,\r
                Handle,\r
                DiskIo,\r
                DiskIo2,\r
                BlockIo,\r
                BlockIo2,\r
                DevicePath,\r
                (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
                HdDev.PartitionStart,\r
                HdDev.PartitionStart + HdDev.PartitionSize - 1,\r
                MBR_SIZE,\r
                (BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)\r
                );\r
\r
      if (!EFI_ERROR (Status)) {\r
        Found = EFI_SUCCESS;\r
      }\r
    }\r
  } else {\r
    //\r
    // It's an extended partition. Follow the extended partition\r
    // chain to get all the logical drives\r
    //\r
    ExtMbrStartingLba = 0;\r
\r
    do {\r
\r
      Status = DiskIo->ReadDisk (\r
                         DiskIo,\r
                         MediaId,\r
                         MultU64x32 (ExtMbrStartingLba, BlockSize),\r
                         BlockSize,\r
                         Mbr\r
                         );\r
      if (EFI_ERROR (Status)) {\r
        Found = Status;\r
        goto Done;\r
      }\r
\r
      if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {\r
        break;\r
      }\r
\r
      if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) ||\r
          (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {\r
        ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);\r
        continue;\r
      }\r
      HdDev.PartitionNumber = PartitionNumber ++;\r
      HdDev.PartitionStart  = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;\r
      HdDev.PartitionSize   = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);\r
      if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) ||\r
          (HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {\r
        break;\r
      }\r
\r
      //\r
      // The signature in EBR(Extended Boot Record) should always be 0.\r
      //\r
      *((UINT32 *) &HdDev.Signature[0]) = 0;\r
\r
      Status = PartitionInstallChildHandle (\r
                 This,\r
                 Handle,\r
                 DiskIo,\r
                 DiskIo2,\r
                 BlockIo,\r
                 BlockIo2,\r
                 DevicePath,\r
                 (EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
                 HdDev.PartitionStart - ParentHdDev.PartitionStart,\r
                 HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,\r
                 MBR_SIZE,\r
                 (BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)\r
                 );\r
      if (!EFI_ERROR (Status)) {\r
        Found = EFI_SUCCESS;\r
      }\r
\r
      if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&\r
          (Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)\r
          ) {\r
        break;\r
      }\r
\r
      ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);\r
      //\r
      // Don't allow partition to be self referencing\r
      //\r
      if (ExtMbrStartingLba == 0) {\r
        break;\r
      }\r
    } while (ExtMbrStartingLba  < ParentHdDev.PartitionSize);\r
  }\r
\r
Done:\r
  FreePool (Mbr);\r
\r
  return Found;\r
}\r
Commit	Line	Data
f42be642	1	/** @file\r
adbcbf8f	2	Decode a hard disk partitioned with the legacy MBR found on most PC's\r
	3	\r
	4	MBR - Master Boot Record is in the first sector of a partitioned hard disk.\r
	5	The MBR supports four partitions per disk. The MBR also contains legacy\r
	6	code that is not run on an EFI system. The legacy code reads the \r
	7	first sector of the active partition into memory and \r
	8	\r
48557c65	9	BPB - BIOS Parameter Block is in the first sector of a FAT file system. \r
adbcbf8f	10	The BPB contains information about the FAT file system. The BPB is \r
	11	always on the first sector of a media. The first sector also contains\r
	12	the legacy boot strap code.\r
	13	\r
493d8e3a	14	Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
e5eed7d3	15	This program and the accompanying materials\r
f42be642	16	are licensed and made available under the terms and conditions of the BSD License\r
	17	which accompanies this distribution. The full text of the license may be found at\r
	18	http://opensource.org/licenses/bsd-license.php\r
	19	\r
	20	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	21	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	22	\r
	23	**/\r
adbcbf8f	24	\r
	25	#include "Partition.h"\r
	26	\r
a8d0c20e	27	/**\r
	28	Test to see if the Mbr buffer is a valid MBR.\r
	29	\r
	30	@param Mbr Parent Handle.\r
	31	@param LastLba Last Lba address on the device.\r
	32	\r
	33	@retval TRUE Mbr is a Valid MBR.\r
	34	@retval FALSE Mbr is not a Valid MBR.\r
	35	\r
	36	**/\r
adbcbf8f	37	BOOLEAN\r
	38	PartitionValidMbr (\r
	39	IN MASTER_BOOT_RECORD *Mbr,\r
	40	IN EFI_LBA LastLba\r
	41	)\r
adbcbf8f	42	{\r
	43	UINT32 StartingLBA;\r
	44	UINT32 EndingLBA;\r
	45	UINT32 NewEndingLBA;\r
	46	INTN Index1;\r
	47	INTN Index2;\r
	48	BOOLEAN MbrValid;\r
	49	\r
	50	if (Mbr->Signature != MBR_SIGNATURE) {\r
	51	return FALSE;\r
	52	}\r
	53	//\r
	54	// The BPB also has this signature, so it can not be used alone.\r
	55	//\r
	56	MbrValid = FALSE;\r
	57	for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {\r
	58	if (Mbr->Partition[Index1].OSIndicator == 0x00 \|\| UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {\r
	59	continue;\r
	60	}\r
	61	\r
	62	MbrValid = TRUE;\r
	63	StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);\r
	64	EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;\r
	65	if (EndingLBA > LastLba) {\r
	66	//\r
	67	// Compatibility Errata:\r
	68	// Some systems try to hide drive space with their INT 13h driver\r
	69	// This does not hide space from the OS driver. This means the MBR\r
	70	// that gets created from DOS is smaller than the MBR created from\r
	71	// a real OS (NT & Win98). This leads to BlockIo->LastBlock being\r
	72	// wrong on some systems FDISKed by the OS.\r
	73	//\r
	74	// return FALSE since no block devices on a system are implemented\r
	75	// with INT 13h\r
	76	//\r
	77	return FALSE;\r
	78	}\r
	79	\r
	80	for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {\r
	81	if (Mbr->Partition[Index2].OSIndicator == 0x00 \|\| UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {\r
	82	continue;\r
	83	}\r
	84	\r
	85	NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;\r
	86	if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {\r
	87	//\r
	88	// This region overlaps with the Index1'th region\r
	89	//\r
	90	return FALSE;\r
	91	}\r
	92	}\r
	93	}\r
	94	//\r
ea7cb08c	95	// None of the regions overlapped so MBR is O.K.\r
adbcbf8f	96	//\r
	97	return MbrValid;\r
	98	}\r
	99	\r
a8d0c20e	100	\r
	101	/**\r
	102	Install child handles if the Handle supports MBR format.\r
	103	\r
490b5ea1	104	@param[in] This Calling context.\r
	105	@param[in] Handle Parent Handle.\r
	106	@param[in] DiskIo Parent DiskIo interface.\r
493d8e3a	107	@param[in] DiskIo2 Parent DiskIo2 interface.\r
490b5ea1	108	@param[in] BlockIo Parent BlockIo interface.\r
	109	@param[in] BlockIo2 Parent BlockIo2 interface.\r
	110	@param[in] DevicePath Parent Device Path.\r
a8d0c20e	111	\r
	112	@retval EFI_SUCCESS A child handle was added.\r
	113	@retval EFI_MEDIA_CHANGED Media change was detected.\r
	114	@retval Others MBR partition was not found.\r
	115	\r
	116	**/\r
adbcbf8f	117	EFI_STATUS\r
	118	PartitionInstallMbrChildHandles (\r
	119	IN EFI_DRIVER_BINDING_PROTOCOL *This,\r
	120	IN EFI_HANDLE Handle,\r
	121	IN EFI_DISK_IO_PROTOCOL *DiskIo,\r
493d8e3a	122	IN EFI_DISK_IO2_PROTOCOL *DiskIo2,\r
adbcbf8f	123	IN EFI_BLOCK_IO_PROTOCOL *BlockIo,\r
490b5ea1	124	IN EFI_BLOCK_IO2_PROTOCOL *BlockIo2,\r
adbcbf8f	125	IN EFI_DEVICE_PATH_PROTOCOL *DevicePath\r
adbcbf8f	126	)\r
adbcbf8f	127	{\r
	128	EFI_STATUS Status;\r
	129	MASTER_BOOT_RECORD *Mbr;\r
	130	UINT32 ExtMbrStartingLba;\r
	131	UINTN Index;\r
	132	HARDDRIVE_DEVICE_PATH HdDev;\r
	133	HARDDRIVE_DEVICE_PATH ParentHdDev;\r
	134	EFI_STATUS Found;\r
	135	UINT32 PartitionNumber;\r
	136	EFI_DEVICE_PATH_PROTOCOL *DevicePathNode;\r
	137	EFI_DEVICE_PATH_PROTOCOL *LastDevicePathNode;\r
490b5ea1	138	UINT32 BlockSize;\r
	139	UINT32 MediaId;\r
	140	EFI_LBA LastBlock;\r
adbcbf8f	141	\r
adbcbf8f	142	Found = EFI_NOT_FOUND;\r
adbcbf8f	143	\r
490b5ea1	144	BlockSize = BlockIo->Media->BlockSize;\r
	145	MediaId = BlockIo->Media->MediaId;\r
	146	LastBlock = BlockIo->Media->LastBlock;\r
	147	\r
	148	Mbr = AllocatePool (BlockSize);\r
adbcbf8f	149	if (Mbr == NULL) {\r
737dfc36	150	return Found;\r
adbcbf8f	151	}\r
adbcbf8f	152	\r
96f99e1d	153	Status = DiskIo->ReadDisk (\r
96f99e1d	154	DiskIo,\r
490b5ea1	155	MediaId,\r
96f99e1d	156	0,\r
490b5ea1	157	BlockSize,\r
96f99e1d	158	Mbr\r
96f99e1d	159	);\r
adbcbf8f	160	if (EFI_ERROR (Status)) {\r
	161	Found = Status;\r
	162	goto Done;\r
	163	}\r
490b5ea1	164	if (!PartitionValidMbr (Mbr, LastBlock)) {\r
adbcbf8f	165	goto Done;\r
	166	}\r
	167	//\r
	168	// We have a valid mbr - add each partition\r
	169	//\r
	170	//\r
	171	// Get starting and ending LBA of the parent block device.\r
	172	//\r
	173	LastDevicePathNode = NULL;\r
	174	ZeroMem (&ParentHdDev, sizeof (ParentHdDev));\r
	175	DevicePathNode = DevicePath;\r
1232b214	176	while (!IsDevicePathEnd (DevicePathNode)) {\r
adbcbf8f	177	LastDevicePathNode = DevicePathNode;\r
1232b214	178	DevicePathNode = NextDevicePathNode (DevicePathNode);\r
adbcbf8f	179	}\r
	180	\r
	181	if (LastDevicePathNode != NULL) {\r
	182	if (DevicePathType (LastDevicePathNode) == MEDIA_DEVICE_PATH &&\r
	183	DevicePathSubType (LastDevicePathNode) == MEDIA_HARDDRIVE_DP\r
	184	) {\r
	185	CopyMem (&ParentHdDev, LastDevicePathNode, sizeof (ParentHdDev));\r
	186	} else {\r
	187	LastDevicePathNode = NULL;\r
	188	}\r
	189	}\r
	190	\r
	191	PartitionNumber = 1;\r
	192	\r
	193	ZeroMem (&HdDev, sizeof (HdDev));\r
	194	HdDev.Header.Type = MEDIA_DEVICE_PATH;\r
	195	HdDev.Header.SubType = MEDIA_HARDDRIVE_DP;\r
	196	SetDevicePathNodeLength (&HdDev.Header, sizeof (HdDev));\r
	197	HdDev.MBRType = MBR_TYPE_PCAT;\r
	198	HdDev.SignatureType = SIGNATURE_TYPE_MBR;\r
	199	\r
	200	if (LastDevicePathNode == NULL) {\r
	201	//\r
	202	// This is a MBR, add each partition\r
	203	//\r
	204	for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {\r
	205	if (Mbr->Partition[Index].OSIndicator == 0x00 \|\| UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA) == 0) {\r
	206	//\r
	207	// Don't use null MBR entries\r
	208	//\r
	209	continue;\r
	210	}\r
	211	\r
	212	if (Mbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION) {\r
	213	//\r
	214	// This is the guard MBR for the GPT. If you ever see a GPT disk with zero partitions you can get here.\r
	215	// We can not produce an MBR BlockIo for this device as the MBR spans the GPT headers. So formating \r
	216	// this BlockIo would corrupt the GPT structures and require a recovery that would corrupt the format\r
	217	// that corrupted the GPT partition. \r
	218	//\r
	219	continue;\r
	220	}\r
	221	\r
	222	HdDev.PartitionNumber = PartitionNumber ++;\r
	223	HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[Index].StartingLBA);\r
	224	HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[Index].SizeInLBA);\r
48557c65	225	CopyMem (HdDev.Signature, &(Mbr->UniqueMbrSignature[0]), sizeof (Mbr->UniqueMbrSignature));\r
adbcbf8f	226	\r
	227	Status = PartitionInstallChildHandle (\r
	228	This,\r
	229	Handle,\r
	230	DiskIo,\r
493d8e3a	231	DiskIo2,\r
adbcbf8f	232	BlockIo,\r
490b5ea1	233	BlockIo2,\r
adbcbf8f	234	DevicePath,\r
	235	(EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
	236	HdDev.PartitionStart,\r
	237	HdDev.PartitionStart + HdDev.PartitionSize - 1,\r
	238	MBR_SIZE,\r
	239	(BOOLEAN) (Mbr->Partition[Index].OSIndicator == EFI_PARTITION)\r
	240	);\r
	241	\r
	242	if (!EFI_ERROR (Status)) {\r
	243	Found = EFI_SUCCESS;\r
	244	}\r
	245	}\r
	246	} else {\r
	247	//\r
	248	// It's an extended partition. Follow the extended partition\r
	249	// chain to get all the logical drives\r
	250	//\r
	251	ExtMbrStartingLba = 0;\r
	252	\r
	253	do {\r
	254	\r
96f99e1d	255	Status = DiskIo->ReadDisk (\r
96f99e1d	256	DiskIo,\r
490b5ea1	257	MediaId,\r
	258	MultU64x32 (ExtMbrStartingLba, BlockSize),\r
	259	BlockSize,\r
96f99e1d	260	Mbr\r
96f99e1d	261	);\r
adbcbf8f	262	if (EFI_ERROR (Status)) {\r
	263	Found = Status;\r
	264	goto Done;\r
	265	}\r
	266	\r
c63cd426	267	if (UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA) == 0) {\r
adbcbf8f	268	break;\r
	269	}\r
	270	\r
	271	if ((Mbr->Partition[0].OSIndicator == EXTENDED_DOS_PARTITION) \|\|\r
	272	(Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION)) {\r
	273	ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);\r
	274	continue;\r
	275	}\r
	276	HdDev.PartitionNumber = PartitionNumber ++;\r
	277	HdDev.PartitionStart = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA) + ExtMbrStartingLba + ParentHdDev.PartitionStart;\r
	278	HdDev.PartitionSize = UNPACK_UINT32 (Mbr->Partition[0].SizeInLBA);\r
	279	if ((HdDev.PartitionStart + HdDev.PartitionSize - 1 >= ParentHdDev.PartitionStart + ParentHdDev.PartitionSize) \|\|\r
	280	(HdDev.PartitionStart <= ParentHdDev.PartitionStart)) {\r
	281	break;\r
	282	}\r
	283	\r
	284	//\r
	285	// The signature in EBR(Extended Boot Record) should always be 0.\r
	286	//\r
	287	((UINT32 ) &HdDev.Signature[0]) = 0;\r
	288	\r
	289	Status = PartitionInstallChildHandle (\r
490b5ea1	290	This,\r
	291	Handle,\r
	292	DiskIo,\r
493d8e3a	293	DiskIo2,\r
490b5ea1	294	BlockIo,\r
	295	BlockIo2,\r
	296	DevicePath,\r
	297	(EFI_DEVICE_PATH_PROTOCOL *) &HdDev,\r
	298	HdDev.PartitionStart - ParentHdDev.PartitionStart,\r
	299	HdDev.PartitionStart - ParentHdDev.PartitionStart + HdDev.PartitionSize - 1,\r
	300	MBR_SIZE,\r
	301	(BOOLEAN) (Mbr->Partition[0].OSIndicator == EFI_PARTITION)\r
	302	);\r
adbcbf8f	303	if (!EFI_ERROR (Status)) {\r
	304	Found = EFI_SUCCESS;\r
	305	}\r
	306	\r
	307	if ((Mbr->Partition[1].OSIndicator != EXTENDED_DOS_PARTITION) &&\r
	308	(Mbr->Partition[1].OSIndicator != EXTENDED_WINDOWS_PARTITION)\r
	309	) {\r
	310	break;\r
	311	}\r
	312	\r
	313	ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[1].StartingLBA);\r
	314	//\r
	315	// Don't allow partition to be self referencing\r
	316	//\r
	317	if (ExtMbrStartingLba == 0) {\r
	318	break;\r
	319	}\r
	320	} while (ExtMbrStartingLba < ParentHdDev.PartitionSize);\r
	321	}\r
	322	\r
	323	Done:\r
	324	FreePool (Mbr);\r
	325	\r
	326	return Found;\r
	327	}\r