FatPkg/FatPei: Fix few typos

[mirror_edk2.git] / FatPkg / FatPei / Mbr.c

/** @file\r
  Routines supporting partition discovery and\r
  logical device reading\r
\r
Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>\r
\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include <IndustryStandard/Mbr.h>\r
#include "FatLitePeim.h"\r
\r
/**\r
  Test to see if the Mbr buffer is a valid MBR\r
\r
  @param[in]  Mbr               Parent Handle\r
  @param[in]  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_PEI_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 Because 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_INT32 (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
  // Non of the regions overlapped so MBR is O.K.\r
  //\r
  return MbrValid;\r
}\r
\r
/**\r
  This function finds Mbr partitions. Main algorithm\r
  is ported from DXE partition driver.\r
\r
  @param[in]  PrivateData       The global memory map\r
  @param[in]  ParentBlockDevNo  The parent block device\r
\r
  @retval TRUE              New partitions are detected and logical block devices\r
                            are added to block device array\r
  @retval FALSE             No new partitions are added\r
\r
**/\r
BOOLEAN\r
FatFindMbrPartitions (\r
  IN  PEI_FAT_PRIVATE_DATA *PrivateData,\r
  IN  UINTN                ParentBlockDevNo\r
  )\r
{\r
  EFI_STATUS            Status;\r
  MASTER_BOOT_RECORD    *Mbr;\r
  UINTN                 Index;\r
  BOOLEAN               Found;\r
  PEI_FAT_BLOCK_DEVICE  *ParentBlockDev;\r
  PEI_FAT_BLOCK_DEVICE  *BlockDev;\r
\r
  if (ParentBlockDevNo > PEI_FAT_MAX_BLOCK_DEVICE - 1) {\r
    return FALSE;\r
  }\r
\r
  ParentBlockDev  = &(PrivateData->BlockDevice[ParentBlockDevNo]);\r
\r
  if (ParentBlockDev->BlockSize > PEI_FAT_MAX_BLOCK_SIZE) {\r
    DEBUG((DEBUG_ERROR, "Device BlockSize %x exceeds FAT_MAX_BLOCK_SIZE\n", ParentBlockDev->BlockSize));\r
    return FALSE;\r
  }\r
\r
  Found           = FALSE;\r
  Mbr             = (MASTER_BOOT_RECORD *) PrivateData->BlockData;\r
\r
  Status = FatReadBlock (\r
            PrivateData,\r
            ParentBlockDevNo,\r
            0,\r
            ParentBlockDev->BlockSize,\r
            Mbr\r
            );\r
\r
  if (EFI_ERROR (Status) || !PartitionValidMbr (Mbr, ParentBlockDev->LastBlock)) {\r
    goto Done;\r
  }\r
  //\r
  // We have a valid mbr - add each partition\r
  //\r
  for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {\r
    if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_INT32 (Mbr->Partition[Index].SizeInLBA) == 0) {\r
      //\r
      // Don't use null MBR entries\r
      //\r
      continue;\r
    }\r
    //\r
    // Register this partition\r
    //\r
    if (PrivateData->BlockDeviceCount < PEI_FAT_MAX_BLOCK_DEVICE) {\r
\r
      Found                       = TRUE;\r
\r
      BlockDev                    = &(PrivateData->BlockDevice[PrivateData->BlockDeviceCount]);\r
\r
      BlockDev->BlockSize         = MBR_SIZE;\r
      BlockDev->LastBlock         = UNPACK_INT32 (Mbr->Partition[Index].SizeInLBA) - 1;\r
      BlockDev->IoAlign           = ParentBlockDev->IoAlign;\r
      BlockDev->Logical           = TRUE;\r
      BlockDev->PartitionChecked  = FALSE;\r
      BlockDev->StartingPos = MultU64x32 (\r
                                UNPACK_INT32 (Mbr->Partition[Index].StartingLBA),\r
                                ParentBlockDev->BlockSize\r
                                );\r
      BlockDev->ParentDevNo = ParentBlockDevNo;\r
\r
      PrivateData->BlockDeviceCount++;\r
    }\r
  }\r
\r
Done:\r
\r
  ParentBlockDev->PartitionChecked = TRUE;\r
  return Found;\r
}\r