FatPkg: Break down Part.c file.

[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
This program and the accompanying materials are licensed and made available\r
under the terms and conditions of the BSD License which accompanies this\r
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 <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
      // Compatability Errata:\r
      //  Some systems try to hide drive space with thier 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