audk/FatPkg/EnhancedFatDxe/DirectoryManage.c

/*++

Copyright (c) 2005 - 2015, 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.


Module Name:

  DirectoryManage.c

Abstract:

  Functions for performing directory entry io

Revision History

--*/

#include "Fat.h"

STATIC
EFI_STATUS
FatAccessEntry (
  IN     FAT_OFILE            *Parent,
  IN     IO_MODE              IoMode,
  IN     UINTN                EntryPos,
  IN OUT VOID                 *Entry
  )
/*++

Routine Description:

  Get a directory entry from disk for the Ofile.

Arguments:

  Parent                - The parent of the OFile which need to update.
  IoMode                - Indicate whether to read directory entry or write directroy entry.
  EntryPos              - The position of the directory entry to be accessed.
  Entry                 - The directory entry read or written.

Returns:

  EFI_SUCCESS           - Access the directory entry sucessfully.
  other                 - An error occurred when reading the directory entry.

--*/
{
  UINTN Position;
  UINTN BufferSize;

  Position = EntryPos * sizeof (FAT_DIRECTORY_ENTRY);
  if (Position >= Parent->FileSize) {
    //
    // End of directory
    //
    ASSERT (IoMode == READ_DATA);
    ((FAT_DIRECTORY_ENTRY *) Entry)->FileName[0] = EMPTY_ENTRY_MARK;
    ((FAT_DIRECTORY_ENTRY *) Entry)->Attributes  = 0;
    return EFI_SUCCESS;
  }

  BufferSize = sizeof (FAT_DIRECTORY_ENTRY);
  return FatAccessOFile (Parent, IoMode, Position, &BufferSize, Entry, NULL);
}

EFI_STATUS
FatStoreDirEnt (
  IN FAT_OFILE            *OFile,
  IN FAT_DIRENT           *DirEnt
  )
/*++

Routine Description:

  Save the directory entry to disk.

Arguments:

  OFile                 - The parent OFile which needs to update.
  DirEnt                - The directory entry to be saved.

Returns:

  EFI_SUCCESS           - Store the directory entry successfully.
  other                 - An error occurred when writing the directory entry.

--*/
{
  EFI_STATUS        Status;
  FAT_DIRECTORY_LFN LfnEntry;
  UINTN             EntryPos;
  CHAR16            *LfnBufferPointer;
  CHAR16            LfnBuffer[MAX_LFN_ENTRIES * LFN_CHAR_TOTAL + 1];
  UINT8             EntryCount;
  UINT8             LfnOrdinal;

  EntryPos   = DirEnt->EntryPos;
  EntryCount = DirEnt->EntryCount;
  //
  // Write directory entry
  //
  Status = FatAccessEntry (OFile, WRITE_DATA, EntryPos, &DirEnt->Entry);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (--EntryCount > 0) {
    //
    // Write LFN directory entry
    //
    SetMem (LfnBuffer, sizeof (CHAR16) * LFN_CHAR_TOTAL * EntryCount, 0xff);
    Status = StrCpyS (
               LfnBuffer,
               sizeof (LfnBuffer) / sizeof (LfnBuffer[0]),
               DirEnt->FileString
               );
    if (EFI_ERROR (Status)) {
      return Status;
    }

    LfnBufferPointer    = LfnBuffer;
    LfnEntry.Attributes = FAT_ATTRIBUTE_LFN;
    LfnEntry.Type       = 0;
    LfnEntry.MustBeZero = 0;
    LfnEntry.Checksum   = FatCheckSum (DirEnt->Entry.FileName);
    for (LfnOrdinal = 1; LfnOrdinal <= EntryCount; LfnOrdinal++) {
      LfnEntry.Ordinal = LfnOrdinal;
      if (LfnOrdinal == EntryCount) {
        LfnEntry.Ordinal |= FAT_LFN_LAST;
      }

      CopyMem (LfnEntry.Name1, LfnBufferPointer, sizeof (CHAR16) * LFN_CHAR1_LEN);
      LfnBufferPointer += LFN_CHAR1_LEN;
      CopyMem (LfnEntry.Name2, LfnBufferPointer, sizeof (CHAR16) * LFN_CHAR2_LEN);
      LfnBufferPointer += LFN_CHAR2_LEN;
      CopyMem (LfnEntry.Name3, LfnBufferPointer, sizeof (CHAR16) * LFN_CHAR3_LEN);
      LfnBufferPointer += LFN_CHAR3_LEN;
      EntryPos--;
      if (DirEnt->Invalid) {
        LfnEntry.Ordinal = DELETE_ENTRY_MARK;
      }

      Status = FatAccessEntry (OFile, WRITE_DATA, EntryPos, &LfnEntry);
      if (EFI_ERROR (Status)) {
        return Status;
      }
    }
  }

  return EFI_SUCCESS;
}

BOOLEAN
FatIsDotDirEnt (
  IN FAT_DIRENT  *DirEnt
  )
/*++

Routine Description:

  Determine whether the directory entry is "." or ".." entry.

Arguments:

  DirEnt               - The corresponding directory entry.

Returns:

  TRUE                 - The directory entry is "." or ".." directory entry
  FALSE                - The directory entry is not "." or ".." directory entry

--*/
{
  CHAR16  *FileString;
  FileString = DirEnt->FileString;
  if (StrCmp (FileString, L".") == 0 || StrCmp (FileString, L"..") == 0) {
    return TRUE;
  }

  return FALSE;
}

STATIC
VOID
FatSetDirEntCluster (
  IN FAT_OFILE    *OFile
  )
/*++

Routine Description:

  Set the OFile's cluster info in its directory entry.

Arguments:

  OFile                 - The corresponding OFile.

Returns:

  None.

--*/
{
  UINTN       Cluster;
  FAT_DIRENT  *DirEnt;

  DirEnt                        = OFile->DirEnt;
  Cluster                       = OFile->FileCluster;
  DirEnt->Entry.FileClusterHigh = (UINT16) (Cluster >> 16);
  DirEnt->Entry.FileCluster     = (UINT16) Cluster;
}

VOID
FatUpdateDirEntClusterSizeInfo (
  IN FAT_OFILE    *OFile
  )
/*++

Routine Description:

  Set the OFile's cluster and size info in its directory entry.

Arguments:

  OFile                 - The corresponding OFile.

Returns:

  None.

--*/
{
  ASSERT (OFile->ODir == NULL);
  OFile->DirEnt->Entry.FileSize = (UINT32) OFile->FileSize;
  FatSetDirEntCluster (OFile);
}

VOID
FatCloneDirEnt (
  IN  FAT_DIRENT          *DirEnt1,
  IN  FAT_DIRENT          *DirEnt2
  )
/*++

Routine Description:

  Copy all the information of DirEnt2 to DirEnt1 except for 8.3 name.

Arguments:

  DirEnt1               - The destination directory entry.
  DirEnt2               - The source directory entry.

Returns:

  None.

--*/
{
  UINT8 *Entry1;
  UINT8 *Entry2;
  Entry1  = (UINT8 *) &DirEnt1->Entry;
  Entry2  = (UINT8 *) &DirEnt2->Entry;
  CopyMem (
    Entry1 + FAT_ENTRY_INFO_OFFSET,
    Entry2 + FAT_ENTRY_INFO_OFFSET,
    sizeof (FAT_DIRECTORY_ENTRY) - FAT_ENTRY_INFO_OFFSET
    );
}

STATIC
VOID
FatLoadLongNameEntry (
  IN FAT_OFILE           *Parent,
  IN FAT_DIRENT          *DirEnt
  )
/*++

Routine Description:

  Get the LFN for the directory entry.

Arguments:

  Parent                - The parent directory.
  DirEnt                - The directory entry to get LFN.

Returns:

  None.

--*/
{
  CHAR16            LfnBuffer[MAX_LFN_ENTRIES * LFN_CHAR_TOTAL + 1];
  CHAR16            *LfnBufferPointer;
  CHAR8             *File8Dot3Name;
  UINTN             EntryPos;
  UINT8             LfnOrdinal;
  UINT8             LfnChecksum;
  FAT_DIRECTORY_LFN LfnEntry;
  EFI_STATUS        Status;

  EntryPos          = DirEnt->EntryPos;
  File8Dot3Name     = DirEnt->Entry.FileName;
  LfnBufferPointer  = LfnBuffer;
  //
  // Computes checksum for LFN
  //
  LfnChecksum = FatCheckSum (File8Dot3Name);
  LfnOrdinal  = 1;
  do {
    if (EntryPos == 0) {
      LfnBufferPointer = LfnBuffer;
      break;
    }

    EntryPos--;
    Status = FatAccessEntry (Parent, READ_DATA, EntryPos, &LfnEntry);
    if (EFI_ERROR (Status) ||
        LfnEntry.Attributes != FAT_ATTRIBUTE_LFN ||
        LfnEntry.MustBeZero != 0 ||
        LfnEntry.Checksum != LfnChecksum ||
        (LfnEntry.Ordinal & (~FAT_LFN_LAST)) != LfnOrdinal ||
        LfnOrdinal > MAX_LFN_ENTRIES
        ) {
      //
      // The directory entry does not have a long file name or
      // some error occurs when loading long file name for a directory entry,
      // and then we load the long name from short name
      //
      LfnBufferPointer = LfnBuffer;
      break;
    }

    CopyMem (LfnBufferPointer, LfnEntry.Name1, sizeof (CHAR16) * LFN_CHAR1_LEN);
    LfnBufferPointer += LFN_CHAR1_LEN;
    CopyMem (LfnBufferPointer, LfnEntry.Name2, sizeof (CHAR16) * LFN_CHAR2_LEN);
    LfnBufferPointer += LFN_CHAR2_LEN;
    CopyMem (LfnBufferPointer, LfnEntry.Name3, sizeof (CHAR16) * LFN_CHAR3_LEN);
    LfnBufferPointer += LFN_CHAR3_LEN;
    LfnOrdinal++;
  } while ((LfnEntry.Ordinal & FAT_LFN_LAST) == 0);
  DirEnt->EntryCount = LfnOrdinal;
  //
  // Terminate current Lfnbuffer
  //
  *LfnBufferPointer = 0;
  if (LfnBufferPointer == LfnBuffer) {
    //
    // Fail to get the long file name from long file name entry,
    // get the file name from short name
    //
    FatGetFileNameViaCaseFlag (
      DirEnt,
      LfnBuffer,
      sizeof (LfnBuffer) / sizeof (LfnBuffer[0])
      );
  }

  DirEnt->FileString = AllocateCopyPool (StrSize (LfnBuffer), LfnBuffer);
}

STATIC
VOID
FatAddDirEnt (
  IN FAT_ODIR             *ODir,
  IN FAT_DIRENT           *DirEnt
  )
/*++

Routine Description:

  Add this directory entry node to the list of directory entries and hash table.

Arguments:

  ODir                  - The parent OFile which needs to be updated.
  DirEnt                - The directory entry to be added.

Returns:

  None.

--*/
{
  if (DirEnt->Link.BackLink == NULL) {
    DirEnt->Link.BackLink = &ODir->ChildList;
  }
  InsertTailList (DirEnt->Link.BackLink, &DirEnt->Link);
  FatInsertToHashTable (ODir, DirEnt);
}

STATIC
EFI_STATUS
FatLoadNextDirEnt (
  IN  FAT_OFILE           *OFile,
  OUT FAT_DIRENT          **PtrDirEnt
  )
/*++

Routine Description:

  Load from disk the next directory entry at current end of directory position

Arguments:

  OFile                 - The parent OFile.
  PtrDirEnt             - The directory entry that is loaded.

Returns:

  EFI_SUCCESS           - Load the directory entry successfully.
  EFI_OUT_OF_RESOURCES  - Out of resource.
  other                 - An error occurred when reading the directory entries.

--*/
{
  EFI_STATUS          Status;
  FAT_DIRENT          *DirEnt;
  FAT_ODIR            *ODir;
  FAT_DIRECTORY_ENTRY Entry;

  ODir = OFile->ODir;
  //
  // Make sure the parent's directory has been opened
  //
  ASSERT (ODir != NULL);
  //
  // Assert we have not reached the end of directory
  //
  ASSERT (!ODir->EndOfDir);
  DirEnt = NULL;

  for (;;) {
    //
    // Read the next directory entry until we find a valid directory entry (excluding lfn entry)
    //
    Status = FatAccessEntry (OFile, READ_DATA, ODir->CurrentEndPos, &Entry);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    if (((UINT8) Entry.FileName[0] != DELETE_ENTRY_MARK) && (Entry.Attributes & FAT_ATTRIBUTE_VOLUME_ID) == 0) {
      //
      // We get a valid directory entry, then handle it
      //
      break;
    }

    ODir->CurrentEndPos++;
  }

  if (Entry.FileName[0] != EMPTY_ENTRY_MARK) {
    //
    // Although FAT spec states this field is always 0 for FAT12 & FAT16, some applications
    // might use it for some special usage, it is safer to zero it in memory for FAT12 & FAT16.
    //
    if (OFile->Volume->FatType != FAT32) {
      Entry.FileClusterHigh = 0;
    }

    //
    // This is a valid directory entry
    //
    DirEnt = AllocateZeroPool (sizeof (FAT_DIRENT));
    if (DirEnt == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }

    DirEnt->Signature = FAT_DIRENT_SIGNATURE;
    //
    // Remember the directory's entry position on disk
    //
    DirEnt->EntryPos = (UINT16) ODir->CurrentEndPos;
    CopyMem (&DirEnt->Entry, &Entry, sizeof (FAT_DIRECTORY_ENTRY));
    FatLoadLongNameEntry (OFile, DirEnt);
    if (DirEnt->FileString == NULL) {
      Status = EFI_OUT_OF_RESOURCES;
      goto Done;
    }
    //
    // Add this directory entry to directory
    //
    FatAddDirEnt (ODir, DirEnt);
    //
    // Point to next directory entry
    //
    ODir->CurrentEndPos++;
  } else {
    ODir->EndOfDir = TRUE;
  }

  *PtrDirEnt = DirEnt;
  return EFI_SUCCESS;

Done:
  FatFreeDirEnt (DirEnt);
  return Status;
}

EFI_STATUS
FatGetDirEntInfo (
  IN     FAT_VOLUME         *Volume,
  IN     FAT_DIRENT         *DirEnt,
  IN OUT UINTN              *BufferSize,
     OUT VOID               *Buffer
  )
/*++

Routine Description:

  Get the directory entry's info into Buffer.

Arguments:

  Volume                - FAT file system volume.
  DirEnt                - The corresponding directory entry.
  BufferSize            - Size of Buffer.
  Buffer                - Buffer containing file info.

Returns:

  EFI_SUCCESS           - Get the file info successfully.
  EFI_BUFFER_TOO_SMALL  - The buffer is too small.

--*/
{
  UINTN               Size;
  UINTN               NameSize;
  UINTN               ResultSize;
  UINTN               Cluster;
  EFI_STATUS          Status;
  EFI_FILE_INFO       *Info;
  FAT_DIRECTORY_ENTRY *Entry;
  FAT_DATE_TIME       FatLastAccess;

  ASSERT_VOLUME_LOCKED (Volume);

  Size        = SIZE_OF_EFI_FILE_INFO;
  NameSize    = StrSize (DirEnt->FileString);
  ResultSize  = Size + NameSize;

  Status      = EFI_BUFFER_TOO_SMALL;
  if (*BufferSize >= ResultSize) {
    Status      = EFI_SUCCESS;
    Entry       = &DirEnt->Entry;
    Info        = Buffer;
    Info->Size  = ResultSize;
    if ((Entry->Attributes & FAT_ATTRIBUTE_DIRECTORY) != 0) {
      Cluster             = (Entry->FileClusterHigh << 16) | Entry->FileCluster;
      Info->PhysicalSize  = FatPhysicalDirSize (Volume, Cluster);
      Info->FileSize      = Info->PhysicalSize;
    } else {
      Info->FileSize      = Entry->FileSize;
      Info->PhysicalSize  = FatPhysicalFileSize (Volume, Entry->FileSize);
    }

    ZeroMem (&FatLastAccess.Time, sizeof (FatLastAccess.Time));
    CopyMem (&FatLastAccess.Date, &Entry->FileLastAccess, sizeof (FatLastAccess.Date));
    FatFatTimeToEfiTime (&FatLastAccess, &Info->LastAccessTime);
    FatFatTimeToEfiTime (&Entry->FileCreateTime, &Info->CreateTime);
    FatFatTimeToEfiTime (&Entry->FileModificationTime, &Info->ModificationTime);
    Info->Attribute = Entry->Attributes & EFI_FILE_VALID_ATTR;
    CopyMem ((CHAR8 *) Buffer + Size, DirEnt->FileString, NameSize);
  }

  *BufferSize = ResultSize;
  return Status;
}

STATIC
EFI_STATUS
FatSearchODir (
  IN  FAT_OFILE      *OFile,
  IN  CHAR16         *FileNameString,
  OUT FAT_DIRENT     **PtrDirEnt
  )
/*++

Routine Description:

  Search the directory for the directory entry whose filename is FileNameString.

Arguments:

  OFile                 - The parent OFile whose directory is to be searched.
  FileNameString        - The filename to be searched.
  PtrDirEnt             - pointer to the directory entry if found.

Returns:

  EFI_SUCCESS           - Find the directory entry or not found.
  other                 - An error occurred when reading the directory entries.

--*/
{
  BOOLEAN     PossibleShortName;
  CHAR8       File8Dot3Name[FAT_NAME_LEN];
  FAT_ODIR    *ODir;
  FAT_DIRENT  *DirEnt;
  EFI_STATUS  Status;

  ODir = OFile->ODir;
  ASSERT (ODir != NULL);
  //
  // Check if the file name is a valid short name
  //
  PossibleShortName = FatCheckIs8Dot3Name (FileNameString, File8Dot3Name);
  //
  // Search the hash table first
  //
  DirEnt = *FatLongNameHashSearch (ODir, FileNameString);
  if (DirEnt == NULL && PossibleShortName) {
      DirEnt = *FatShortNameHashSearch (ODir, File8Dot3Name);
  }
  if (DirEnt == NULL) {
    //
    // We fail to get the directory entry from hash table; we then
    // search the rest directory
    //
    while (!ODir->EndOfDir) {
      Status = FatLoadNextDirEnt (OFile, &DirEnt);
      if (EFI_ERROR (Status)) {
        return Status;
      }

      if (DirEnt != NULL) {
        if (FatStriCmp (FileNameString, DirEnt->FileString) == 0) {
          break;
        }

        if (PossibleShortName && CompareMem (File8Dot3Name, DirEnt->Entry.FileName, FAT_NAME_LEN) == 0) {
          break;
        }
      }
    }
  }

  *PtrDirEnt = DirEnt;
  return EFI_SUCCESS;
}

VOID
FatResetODirCursor (
  IN FAT_OFILE    *OFile
  )
/*++

Routine Description:

  Set the OFile's current directory cursor to the list head.

Arguments:

  OFile                 - The directory OFile whose directory cursor is reset.

Returns:

  None.

--*/
{
  FAT_ODIR  *ODir;

  ODir = OFile->ODir;
  ASSERT (ODir != NULL);
  ODir->CurrentCursor = &(ODir->ChildList);
  ODir->CurrentPos    = 0;
}

EFI_STATUS
FatGetNextDirEnt (
  IN  FAT_OFILE     *OFile,
  OUT FAT_DIRENT    **PtrDirEnt
  )
/*++

Routine Description:

  Set the directory's cursor to the next and get the next directory entry.

Arguments:

  OFile                 - The parent OFile.
  PtrDirEnt             - The next directory entry.

Returns:

  EFI_SUCCESS           - We get the next directory entry successfully.
  other                 - An error occurred when get next directory entry.

--*/
{
  EFI_STATUS  Status;
  FAT_DIRENT  *DirEnt;
  FAT_ODIR    *ODir;

  ODir = OFile->ODir;
  ASSERT (ODir != NULL);
  if (ODir->CurrentCursor->ForwardLink == &ODir->ChildList) {
    //
    // End of directory, we will try one more time
    //
    if (!ODir->EndOfDir) {
      //
      // Read directory from disk
      //
      Status = FatLoadNextDirEnt (OFile, &DirEnt);
      if (EFI_ERROR (Status)) {
        return Status;
      }
    }
  }

  if (ODir->CurrentCursor->ForwardLink == &ODir->ChildList) {
    //
    // End of directory, return NULL
    //
    DirEnt              = NULL;
    ODir->CurrentPos    = ODir->CurrentEndPos;
  } else {
    ODir->CurrentCursor = ODir->CurrentCursor->ForwardLink;
    DirEnt              = DIRENT_FROM_LINK (ODir->CurrentCursor);
    ODir->CurrentPos    = DirEnt->EntryPos + 1;
  }

  *PtrDirEnt = DirEnt;
  return EFI_SUCCESS;
}

STATIC
VOID
FatSetEntryCount (
  IN FAT_OFILE    *OFile,
  IN FAT_DIRENT   *DirEnt
  )
/*++

Routine Description:

  Set the directory entry count according to the filename.

Arguments:

  OFile                 - The corresponding OFile.
  DirEnt                - The directory entry to be set.

Returns:

  None.

--*/
{
  CHAR16  *FileString;
  CHAR8   *File8Dot3Name;

  //
  // Get new entry count and set the 8.3 name
  //
  DirEnt->EntryCount  = 1;
  FileString          = DirEnt->FileString;
  File8Dot3Name       = DirEnt->Entry.FileName;
  SetMem (File8Dot3Name, FAT_NAME_LEN, ' ');
  if (StrCmp (FileString, L".") == 0) {
    //
    // "." entry
    //
    File8Dot3Name[0] = '.';
    FatCloneDirEnt (DirEnt, OFile->DirEnt);
  } else if (StrCmp (FileString, L"..") == 0) {
    //
    // ".." entry
    //
    File8Dot3Name[0]  = '.';
    File8Dot3Name[1]  = '.';
    FatCloneDirEnt (DirEnt, OFile->Parent->DirEnt);
  } else {
    //
    // Normal name
    //
    if (FatCheckIs8Dot3Name (FileString, File8Dot3Name)) {
      //
      // This file name is a valid 8.3 file name, we need to further check its case flag
      //
      FatSetCaseFlag (DirEnt);
    } else {
      //
      // The file name is not a valid 8.3 name we need to generate an 8.3 name for it
      //
      FatCreate8Dot3Name (OFile, DirEnt);
      DirEnt->EntryCount = (UINT8)(LFN_ENTRY_NUMBER (StrLen (FileString)) + DirEnt->EntryCount);
    }
  }
}

STATIC
EFI_STATUS
FatExpandODir (
  IN FAT_OFILE  *OFile
  )
/*++

Routine Description:

  Append a zero cluster to the current OFile.

Arguments:

  OFile        - The directory OFile which needs to be updated.

Returns:

  EFI_SUCCESS  - Append a zero cluster to the OFile successfully.
  other        - An error occurred when appending the zero cluster.

--*/
{
  return FatExpandOFile (OFile, OFile->FileSize + OFile->Volume->ClusterSize);
}

STATIC
EFI_STATUS
FatSeekVolumeId (
  IN  FAT_OFILE            *Root,
  OUT FAT_DIRENT           *DirEnt
  )
/*++

Routine Description:

  Search the Root OFile for the possible volume label.

Arguments:

  Root                  - The Root OFile.
  DirEnt                - The returned directory entry of volume label.

Returns:

  EFI_SUCCESS           - The search process is completed successfully.
  other                 - An error occurred when searching volume label.

--*/
{
  EFI_STATUS          Status;
  UINTN               EntryPos;
  FAT_DIRECTORY_ENTRY *Entry;

  EntryPos        = 0;
  Entry           = &DirEnt->Entry;
  DirEnt->Invalid = TRUE;
  do {
    Status = FatAccessEntry (Root, READ_DATA, EntryPos, Entry);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    if (((UINT8) Entry->FileName[0] != DELETE_ENTRY_MARK) && (((Entry->Attributes) & (~FAT_ATTRIBUTE_ARCHIVE)) == FAT_ATTRIBUTE_VOLUME_ID)) {
      DirEnt->EntryPos   = (UINT16) EntryPos;
      DirEnt->EntryCount = 1;
      DirEnt->Invalid    = FALSE;
      break;
    }

    EntryPos++;
  } while (Entry->FileName[0] != EMPTY_ENTRY_MARK);
  return EFI_SUCCESS;
}

STATIC
EFI_STATUS
FatFirstFitInsertDirEnt (
  IN FAT_OFILE    *OFile,
  IN FAT_DIRENT   *DirEnt
  )
/*++

Routine Description:

  Use First Fit Algorithm to insert directory entry.
  Only this function will erase "E5" entries in a directory.
  In view of safest recovery, this function will only be triggered
  when maximum directory entry number has reached.

Arguments:

  OFile                 - The corresponding OFile.
  DirEnt                - The directory entry to be inserted.

Returns:

  EFI_SUCCESS           - The directory entry has been successfully inserted.
  EFI_VOLUME_FULL       - The directory can not hold more directory entries.
  Others                - Some error occurred when inserting new directory entries.

--*/
{
  EFI_STATUS      Status;
  FAT_ODIR        *ODir;
  LIST_ENTRY      *CurrentEntry;
  FAT_DIRENT      *CurrentDirEnt;
  UINT32          CurrentPos;
  UINT32          LabelPos;
  UINT32          NewEntryPos;
  UINT16          EntryCount;
  FAT_DIRENT      LabelDirEnt;

  LabelPos = 0;
  if (OFile->Parent == NULL) {
    Status = FatSeekVolumeId (OFile, &LabelDirEnt);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    if (!LabelDirEnt.Invalid) {
      LabelPos = LabelDirEnt.EntryPos;
    }
  }

  EntryCount  = DirEnt->EntryCount;
  NewEntryPos = EntryCount;
  CurrentPos  = 0;
  ODir        = OFile->ODir;
  for (CurrentEntry = ODir->ChildList.ForwardLink;
       CurrentEntry != &ODir->ChildList;
       CurrentEntry = CurrentEntry->ForwardLink
      ) {
    CurrentDirEnt = DIRENT_FROM_LINK (CurrentEntry);
    if (NewEntryPos + CurrentDirEnt->EntryCount <= CurrentDirEnt->EntryPos) {
      if (LabelPos > NewEntryPos || LabelPos <= CurrentPos) {
        //
        // first fit succeeded
        //
        goto Done;
      }
    }

    CurrentPos  = CurrentDirEnt->EntryPos;
    NewEntryPos = CurrentPos + EntryCount;
  }

  if (NewEntryPos >= ODir->CurrentEndPos) {
    return EFI_VOLUME_FULL;
  }

Done:
  DirEnt->EntryPos   = (UINT16) NewEntryPos;
  DirEnt->Link.BackLink = CurrentEntry;
  return EFI_SUCCESS;
}

STATIC
EFI_STATUS
FatNewEntryPos (
  IN FAT_OFILE    *OFile,
  IN FAT_DIRENT   *DirEnt
  )
/*++

Routine Description:

  Find the new directory entry position for the directory entry.

Arguments:

  OFile                 - The corresponding OFile.
  DirEnt                - The directory entry whose new position is to be set.

Returns:

  EFI_SUCCESS           - The new directory entry position is successfully found.
  EFI_VOLUME_FULL       - The directory has reach its maximum capacity.
  other                 - An error occurred when reading the directory entry.

--*/
{
  EFI_STATUS  Status;
  FAT_ODIR    *ODir;
  FAT_DIRENT  *TempDirEnt;
  UINT32      NewEndPos;

  ODir = OFile->ODir;
  ASSERT (ODir != NULL);
  //
  // Make sure the whole directory has been loaded
  //
  while (!ODir->EndOfDir) {
    Status = FatLoadNextDirEnt (OFile, &TempDirEnt);
    if (EFI_ERROR (Status)) {
      return Status;
    }
  }
  //
  // We will append this entry to the end of directory
  //
  FatGetCurrentFatTime (&DirEnt->Entry.FileCreateTime);
  CopyMem (&DirEnt->Entry.FileModificationTime, &DirEnt->Entry.FileCreateTime, sizeof (FAT_DATE_TIME));
  CopyMem (&DirEnt->Entry.FileLastAccess, &DirEnt->Entry.FileCreateTime.Date, sizeof (FAT_DATE));
  NewEndPos = ODir->CurrentEndPos + DirEnt->EntryCount;
  if (NewEndPos * sizeof (FAT_DIRECTORY_ENTRY) > OFile->FileSize) {
    if (NewEndPos >= (OFile->IsFixedRootDir ? OFile->Volume->RootEntries : FAT_MAX_DIRENTRY_COUNT)) {
      //
      // We try to use fist fit algorithm to insert this directory entry
      //
      return FatFirstFitInsertDirEnt (OFile, DirEnt);
    }
    //
    // We should allocate a new cluster for this directory
    //
    Status = FatExpandODir (OFile);
    if (EFI_ERROR (Status)) {
      return Status;
    }
  }
  //
  // We append our directory entry at the end of directory file
  //
  ODir->CurrentEndPos = NewEndPos;
  DirEnt->EntryPos = (UINT16) (ODir->CurrentEndPos - 1);
  return EFI_SUCCESS;
}

EFI_STATUS
FatGetVolumeEntry (
  IN FAT_VOLUME           *Volume,
  IN CHAR16               *Name
  )
/*++

Routine Description:

  Get the directory entry for the volume.

Arguments:

  Volume                - FAT file system volume.
  Name                  - The file name of the volume.

Returns:

  EFI_SUCCESS           - Update the volume with the directory entry sucessfully.
  others                - An error occurred when getting volume label.

--*/
{
  EFI_STATUS  Status;
  FAT_DIRENT  LabelDirEnt;

  *Name   = 0;
  Status  = FatSeekVolumeId (Volume->Root, &LabelDirEnt);
  if (!EFI_ERROR (Status)) {
    if (!LabelDirEnt.Invalid) {
      FatNameToStr (LabelDirEnt.Entry.FileName, FAT_NAME_LEN, FALSE, Name);
    }
  }

  return Status;
}

EFI_STATUS
FatSetVolumeEntry (
  IN FAT_VOLUME           *Volume,
  IN CHAR16               *Name
  )
/*++

Routine Description:

  Set the relevant directory entry into disk for the volume.

Arguments:

  Volume              - FAT file system volume.
  Name                - The new file name of the volume.

Returns:

  EFI_SUCCESS         - Update the Volume sucessfully.
  EFI_UNSUPPORTED     - The input label is not a valid volume label.
  other               - An error occurred when setting volume label.

--*/
{
  EFI_STATUS  Status;
  FAT_DIRENT  LabelDirEnt;
  FAT_OFILE   *Root;

  Root    = Volume->Root;
  Status  = FatSeekVolumeId (Volume->Root, &LabelDirEnt);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  if (LabelDirEnt.Invalid) {
    //
    // If there is not the relevant directory entry, create a new one
    //
    ZeroMem (&LabelDirEnt, sizeof (FAT_DIRENT));
    LabelDirEnt.EntryCount = 1;
    Status                 = FatNewEntryPos (Root, &LabelDirEnt);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    LabelDirEnt.Entry.Attributes = FAT_ATTRIBUTE_VOLUME_ID;
  }

  SetMem (LabelDirEnt.Entry.FileName, FAT_NAME_LEN, ' ');
  if (FatStrToFat (Name, FAT_NAME_LEN, LabelDirEnt.Entry.FileName)) {
    return EFI_UNSUPPORTED;
  }

  FatGetCurrentFatTime (&LabelDirEnt.Entry.FileModificationTime);
  return FatStoreDirEnt (Root, &LabelDirEnt);
}

EFI_STATUS
FatCreateDotDirEnts (
  IN FAT_OFILE          *OFile
  )
/*++

Routine Description:

  Create "." and ".." directory entries in the newly-created parent OFile.

Arguments:

  OFile                 - The parent OFile.

Returns:

  EFI_SUCCESS           - The dot directory entries are successfully created.
  other                 - An error occurred when creating the directory entry.

--*/
{
  EFI_STATUS  Status;
  FAT_DIRENT  *DirEnt;

  Status = FatExpandODir (OFile);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  FatSetDirEntCluster (OFile);
  //
  // Create "."
  //
  Status = FatCreateDirEnt (OFile, L".", FAT_ATTRIBUTE_DIRECTORY, &DirEnt);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Create ".."
  //
  Status = FatCreateDirEnt (OFile, L"..", FAT_ATTRIBUTE_DIRECTORY, &DirEnt);
  return Status;
}

EFI_STATUS
FatCreateDirEnt (
  IN  FAT_OFILE         *OFile,
  IN  CHAR16            *FileName,
  IN  UINT8             Attributes,
  OUT FAT_DIRENT        **PtrDirEnt
  )
/*++

Routine Description:

  Create a directory entry in the parent OFile.

Arguments:

  OFile                 - The parent OFile.
  FileName              - The filename of the newly-created directory entry.
  Attributes            - The attribute of the newly-created directory entry.
  PtrDirEnt             - The pointer to the newly-created directory entry.

Returns:

  EFI_SUCCESS           - The directory entry is successfully created.
  EFI_OUT_OF_RESOURCES  - Not enough memory to create the directory entry.
  other                 - An error occurred when creating the directory entry.

--*/
{
  FAT_DIRENT  *DirEnt;
  FAT_ODIR    *ODir;
  EFI_STATUS  Status;

  ASSERT (OFile != NULL);
  ODir = OFile->ODir;
  ASSERT (ODir != NULL);
  DirEnt = AllocateZeroPool (sizeof (FAT_DIRENT));
  if (DirEnt == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  DirEnt->Signature   = FAT_DIRENT_SIGNATURE;
  DirEnt->FileString  = AllocateCopyPool (StrSize (FileName), FileName);
  if (DirEnt->FileString == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto Done;
  }
  //
  // Determine how many directory entries we need
  //
  FatSetEntryCount (OFile, DirEnt);
  //
  // Determine the file's directory entry position
  //
  Status = FatNewEntryPos (OFile, DirEnt);
  if (EFI_ERROR (Status)) {
    goto Done;
  }

  FatAddDirEnt (ODir, DirEnt);
  DirEnt->Entry.Attributes = Attributes;
  *PtrDirEnt               = DirEnt;
  DEBUG ((EFI_D_INFO, "FSOpen: Created new directory entry '%S'\n", DirEnt->FileString));
  return FatStoreDirEnt (OFile, DirEnt);

Done:
  FatFreeDirEnt (DirEnt);
  return Status;
}

EFI_STATUS
FatRemoveDirEnt (
  IN FAT_OFILE    *OFile,
  IN FAT_DIRENT   *DirEnt
  )
/*++

Routine Description:

  Remove this directory entry node from the list of directory entries and hash table.

Arguments:

  OFile                - The parent OFile.
  DirEnt               - The directory entry to be removed.

Returns:

  EFI_SUCCESS          - The directory entry is successfully removed.
  other                - An error occurred when removing the directory entry.

--*/
{
  FAT_ODIR  *ODir;

  ODir = OFile->ODir;
  if (ODir->CurrentCursor == &DirEnt->Link) {
    //
    // Move the directory cursor to its previous directory entry
    //
    ODir->CurrentCursor = ODir->CurrentCursor->BackLink;
  }
  //
  // Remove from directory entry list
  //
  RemoveEntryList (&DirEnt->Link);
  //
  // Remove from hash table
  //
  FatDeleteFromHashTable (ODir, DirEnt);
  DirEnt->Entry.FileName[0] = DELETE_ENTRY_MARK;
  DirEnt->Invalid           = TRUE;
  return FatStoreDirEnt (OFile, DirEnt);
}

EFI_STATUS
FatOpenDirEnt (
  IN FAT_OFILE         *Parent,
  IN FAT_DIRENT        *DirEnt
  )
/*++

Routine Description:

  Open the directory entry to get the OFile.

Arguments:

  OFile                 - The parent OFile.
  DirEnt                - The directory entry to be opened.

Returns:

  EFI_SUCCESS           - The directory entry is successfully opened.
  EFI_OUT_OF_RESOURCES  - not enough memory to allocate a new OFile.
  other                 - An error occurred when opening the directory entry.

--*/
{
  FAT_OFILE   *OFile;
  FAT_VOLUME  *Volume;

  if (DirEnt->OFile == NULL) {
    //
    // Open the directory entry
    //
    OFile = AllocateZeroPool (sizeof (FAT_OFILE));
    if (OFile == NULL) {
      return EFI_OUT_OF_RESOURCES;
    }

    OFile->Signature = FAT_OFILE_SIGNATURE;
    InitializeListHead (&OFile->Opens);
    InitializeListHead (&OFile->ChildHead);
    OFile->Parent = Parent;
    OFile->DirEnt = DirEnt;
    if (Parent != NULL) {
      //
      // The newly created OFile is not root
      //
      Volume             = Parent->Volume;
      OFile->FullPathLen = Parent->FullPathLen + 1 + StrLen (DirEnt->FileString);
      OFile->FileCluster = ((DirEnt->Entry.FileClusterHigh) << 16) | (DirEnt->Entry.FileCluster);
      InsertTailList (&Parent->ChildHead, &OFile->ChildLink);
    } else {
      //
      // The newly created OFile is root
      //
      Volume                = VOLUME_FROM_ROOT_DIRENT (DirEnt);
      Volume->Root          = OFile;
      OFile->FileCluster    = Volume->RootCluster;
      if (Volume->FatType  != FAT32) {
        OFile->IsFixedRootDir  = TRUE;
      }
    }

    OFile->FileCurrentCluster  = OFile->FileCluster;
    OFile->Volume              = Volume;
    InsertHeadList (&Volume->CheckRef, &OFile->CheckLink);

    OFile->FileSize = DirEnt->Entry.FileSize;
    if ((DirEnt->Entry.Attributes & FAT_ATTRIBUTE_DIRECTORY) != 0) {
      if (OFile->IsFixedRootDir) {
        OFile->FileSize = Volume->RootEntries * sizeof (FAT_DIRECTORY_ENTRY);
      } else {
        OFile->FileSize = FatPhysicalDirSize (Volume, OFile->FileCluster);
      }

      FatRequestODir (OFile);
      if (OFile->ODir == NULL) {
        return EFI_OUT_OF_RESOURCES;
      }
    }

    DirEnt->OFile = OFile;
  }

  return EFI_SUCCESS;
}

VOID
FatCloseDirEnt (
  IN FAT_DIRENT        *DirEnt
  )
/*++

Routine Description:

  Close the directory entry and free the OFile.

Arguments:

  DirEnt               - The directory entry to be closed.

Returns:

  EFI_SUCCESS          - The directory entry is successfully opened.
  Other                - An error occurred when opening the directory entry.

--*/
{
  FAT_OFILE   *OFile;
  FAT_VOLUME  *Volume;

  OFile   = DirEnt->OFile;
  ASSERT (OFile != NULL);
  Volume  = OFile->Volume;

  if (OFile->ODir != NULL) {
    FatDiscardODir (OFile);
  }

  if (OFile->Parent == NULL) {
    Volume->Root = NULL;
  } else {
    RemoveEntryList (&OFile->ChildLink);
  }

  FreePool (OFile);
  DirEnt->OFile = NULL;
  if (DirEnt->Invalid == TRUE) {
    //
    // Free directory entry itself
    //
    FatFreeDirEnt (DirEnt);
  }
}

EFI_STATUS
FatLocateOFile (
  IN OUT FAT_OFILE        **PtrOFile,
  IN     CHAR16           *FileName,
  IN     UINT8            Attributes,
     OUT CHAR16           *NewFileName
  )
/*++

Routine Description:

  Traverse filename and open all OFiles that can be opened.
  Update filename pointer to the component that can't be opened.
  If more than one name component remains, returns an error;
  otherwise, return the remaining name component so that the caller might choose to create it.

Arguments:
  PtrOFile              - As input, the reference OFile; as output, the located OFile.
  FileName              - The file name relevant to the OFile.
  Attributes            - The attribute of the destination OFile.
  NewFileName           - The remaining file name.

Returns:

  EFI_NOT_FOUND         - The file name can't be opened and there is more than one
                          components within the name left (this means the name can
                          not be created either).
  EFI_INVALID_PARAMETER - The parameter is not valid.
  EFI_SUCCESS           - Open the file successfully.
  other                 - An error occured when locating the OFile.

--*/
{
  EFI_STATUS  Status;
  FAT_VOLUME  *Volume;
  CHAR16      ComponentName[EFI_PATH_STRING_LENGTH];
  UINTN       FileNameLen;
  BOOLEAN     DirIntended;
  CHAR16      *Next;
  FAT_OFILE   *OFile;
  FAT_DIRENT  *DirEnt;

  DirEnt = NULL;

  FileNameLen = StrLen (FileName);
  if (FileNameLen == 0) {
    return EFI_INVALID_PARAMETER;
  }

  OFile       = *PtrOFile;
  Volume      = OFile->Volume;

  DirIntended = FALSE;
  if (FileName[FileNameLen - 1] == PATH_NAME_SEPARATOR) {
    DirIntended = TRUE;
  }
  //
  // If name starts with path name separator, then move to root OFile
  //
  if (*FileName == PATH_NAME_SEPARATOR) {
    OFile = Volume->Root;
    FileName++;
    FileNameLen--;
  }
  //
  // Per FAT Spec the file name should meet the following criteria:
  //   C1. Length (FileLongName) <= 255
  //   C2. Length (X:FileFullPath<NUL>) <= 260
  // Here we check C2 first.
  //
  if (2 + OFile->FullPathLen + 1 + FileNameLen + 1 > EFI_PATH_STRING_LENGTH) {
    //
    // Full path length can not surpass 256
    //
    return EFI_INVALID_PARAMETER;
  }
  //
  // Start at current location
  //
  Next = FileName;
  for (;;) {
    //
    // Get the next component name
    //
    FileName = Next;
    Next     = FatGetNextNameComponent (FileName, ComponentName);

    //
    // If end of the file name, we're done
    //
    if (ComponentName[0] == 0) {
      if (DirIntended && OFile->ODir == NULL) {
        return EFI_NOT_FOUND;
      }

      NewFileName[0] = 0;
      break;
    }
    //
    // If "dot", then current
    //
    if (StrCmp (ComponentName, L".") == 0) {
      continue;
    }
    //
    // If "dot dot", then parent
    //
    if (StrCmp (ComponentName, L"..") == 0) {
      if (OFile->Parent == NULL) {
        return EFI_INVALID_PARAMETER;
      }
      OFile = OFile->Parent;
      continue;
    }

    if (!FatFileNameIsValid (ComponentName, NewFileName)) {
      return EFI_INVALID_PARAMETER;
    }
    //
    // We have a component name, try to open it
    //
    if (OFile->ODir == NULL) {
      //
      // This file isn't a directory, can't open it
      //
      return EFI_NOT_FOUND;
    }
    //
    // Search the compName in the directory
    //
    Status = FatSearchODir (OFile, NewFileName, &DirEnt);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    if (DirEnt == NULL) {
      //
      // component name is not found in the directory
      //
      if (*Next != 0) {
        return EFI_NOT_FOUND;
      }

      if (DirIntended && (Attributes & FAT_ATTRIBUTE_DIRECTORY) == 0) {
        return EFI_INVALID_PARAMETER;
      }
      //
      // It's the last component name - return with the open
      // path and the remaining name
      //
      break;
    }

    Status = FatOpenDirEnt (OFile, DirEnt);
    if (EFI_ERROR (Status)) {
      return Status;
    }

    OFile = DirEnt->OFile;
  }

  *PtrOFile = OFile;
  return EFI_SUCCESS;
}