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audk/FatPkg/EnhancedFatDxe/FileSpace.c

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/** @file
Routines dealing with disk spaces and FAT table entries.
Copyright (c) 2005 - 2013, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "Fat.h"
/**
Get the FAT entry of the volume, which is identified with the Index.
@param Volume - FAT file system volume.
@param Index - The index of the FAT entry of the volume.
@return The buffer of the FAT entry
**/
STATIC
VOID *
FatLoadFatEntry (
IN FAT_VOLUME *Volume,
IN UINTN Index
)
{
UINTN Pos;
EFI_STATUS Status;
if (Index > (Volume->MaxCluster + 1)) {
Volume->FatEntryBuffer = (UINT32)-1;
return &Volume->FatEntryBuffer;
}
//
// Compute buffer position needed
//
switch (Volume->FatType) {
case Fat12:
Pos = FAT_POS_FAT12 (Index);
break;
case Fat16:
Pos = FAT_POS_FAT16 (Index);
break;
default:
Pos = FAT_POS_FAT32 (Index);
}
//
// Set the position and read the buffer
//
Volume->FatEntryPos = Volume->FatPos + Pos;
Status = FatDiskIo (
Volume,
ReadFat,
Volume->FatEntryPos,
Volume->FatEntrySize,
&Volume->FatEntryBuffer,
NULL
);
if (EFI_ERROR (Status)) {
Volume->FatEntryBuffer = (UINT32)-1;
}
return &Volume->FatEntryBuffer;
}
/**
Get the FAT entry value of the volume, which is identified with the Index.
@param Volume - FAT file system volume.
@param Index - The index of the FAT entry of the volume.
@return The value of the FAT entry.
**/
STATIC
UINTN
FatGetFatEntry (
IN FAT_VOLUME *Volume,
IN UINTN Index
)
{
VOID *Pos;
UINT8 *En12;
UINT16 *En16;
UINT32 *En32;
UINTN Accum;
Pos = FatLoadFatEntry (Volume, Index);
if (Index > (Volume->MaxCluster + 1)) {
return (UINTN)-1;
}
switch (Volume->FatType) {
case Fat12:
En12 = Pos;
Accum = En12[0] | (En12[1] << 8);
Accum = FAT_ODD_CLUSTER_FAT12 (Index) ? (Accum >> 4) : (Accum & FAT_CLUSTER_MASK_FAT12);
Accum = Accum | ((Accum >= FAT_CLUSTER_SPECIAL_FAT12) ? FAT_CLUSTER_SPECIAL_EXT : 0);
break;
case Fat16:
En16 = Pos;
Accum = *En16;
Accum = Accum | ((Accum >= FAT_CLUSTER_SPECIAL_FAT16) ? FAT_CLUSTER_SPECIAL_EXT : 0);
break;
default:
En32 = Pos;
Accum = *En32 & FAT_CLUSTER_MASK_FAT32;
Accum = Accum | ((Accum >= FAT_CLUSTER_SPECIAL_FAT32) ? FAT_CLUSTER_SPECIAL_EXT : 0);
}
return Accum;
}
/**
Set the FAT entry value of the volume, which is identified with the Index.
@param Volume - FAT file system volume.
@param Index - The index of the FAT entry of the volume.
@param Value - The new value of the FAT entry.
@retval EFI_SUCCESS - Set the new FAT entry value successfully.
@retval EFI_VOLUME_CORRUPTED - The FAT type of the volume is error.
@return other - An error occurred when operation the FAT entries.
**/
STATIC
EFI_STATUS
FatSetFatEntry (
IN FAT_VOLUME *Volume,
IN UINTN Index,
IN UINTN Value
)
{
VOID *Pos;
UINT8 *En12;
UINT16 *En16;
UINT32 *En32;
UINTN Accum;
EFI_STATUS Status;
UINTN OriginalVal;
if (Index < FAT_MIN_CLUSTER) {
return EFI_VOLUME_CORRUPTED;
}
OriginalVal = FatGetFatEntry (Volume, Index);
if ((Value == FAT_CLUSTER_FREE) && (OriginalVal != FAT_CLUSTER_FREE)) {
Volume->FatInfoSector.FreeInfo.ClusterCount += 1;
if (Index < Volume->FatInfoSector.FreeInfo.NextCluster) {
Volume->FatInfoSector.FreeInfo.NextCluster = (UINT32)Index;
}
} else if ((Value != FAT_CLUSTER_FREE) && (OriginalVal == FAT_CLUSTER_FREE)) {
if (Volume->FatInfoSector.FreeInfo.ClusterCount != 0) {
Volume->FatInfoSector.FreeInfo.ClusterCount -= 1;
}
}
//
// Make sure the entry is in memory
//
Pos = FatLoadFatEntry (Volume, Index);
//
// Update the value
//
switch (Volume->FatType) {
case Fat12:
En12 = Pos;
Accum = En12[0] | (En12[1] << 8);
Value = Value & FAT_CLUSTER_MASK_FAT12;
if (FAT_ODD_CLUSTER_FAT12 (Index)) {
Accum = (Value << 4) | (Accum & 0xF);
} else {
Accum = Value | (Accum & FAT_CLUSTER_UNMASK_FAT12);
}
En12[0] = (UINT8)(Accum & 0xFF);
En12[1] = (UINT8)(Accum >> 8);
break;
case Fat16:
En16 = Pos;
*En16 = (UINT16)Value;
break;
default:
En32 = Pos;
*En32 = (*En32 & FAT_CLUSTER_UNMASK_FAT32) | (UINT32)(Value & FAT_CLUSTER_MASK_FAT32);
}
//
// If the volume's dirty bit is not set, set it now
//
if (!Volume->FatDirty && (Volume->FatType != Fat12)) {
Volume->FatDirty = TRUE;
FatAccessVolumeDirty (Volume, WriteFat, &Volume->DirtyValue);
}
//
// Write the updated fat entry value to the volume
// The fat is the first fat, and other fat will be in sync
// when the FAT cache flush back.
//
Status = FatDiskIo (
Volume,
WriteFat,
Volume->FatEntryPos,
Volume->FatEntrySize,
&Volume->FatEntryBuffer,
NULL
);
return Status;
}
/**
Free the cluster chain.
@param Volume - FAT file system volume.
@param Cluster - The first cluster of cluster chain.
@retval EFI_SUCCESS - The cluster chain is freed successfully.
@retval EFI_VOLUME_CORRUPTED - There are errors in the file's clusters.
**/
STATIC
EFI_STATUS
FatFreeClusters (
IN FAT_VOLUME *Volume,
IN UINTN Cluster
)
{
UINTN LastCluster;
while (!FAT_END_OF_FAT_CHAIN (Cluster)) {
if ((Cluster == FAT_CLUSTER_FREE) || (Cluster >= FAT_CLUSTER_SPECIAL)) {
DEBUG ((DEBUG_INIT | DEBUG_ERROR, "FatShrinkEof: cluster chain corrupt\n"));
return EFI_VOLUME_CORRUPTED;
}
LastCluster = Cluster;
Cluster = FatGetFatEntry (Volume, Cluster);
FatSetFatEntry (Volume, LastCluster, FAT_CLUSTER_FREE);
}
return EFI_SUCCESS;
}
/**
Allocate a free cluster and return the cluster index.
@param Volume - FAT file system volume.
@return The index of the free cluster
**/
STATIC
UINTN
FatAllocateCluster (
IN FAT_VOLUME *Volume
)
{
UINTN Cluster;
//
// Start looking at FatFreePos for the next unallocated cluster
//
if (Volume->DiskError) {
return (UINTN)FAT_CLUSTER_LAST;
}
for ( ; ;) {
//
// If the end of the list, return no available cluster
//
if (Volume->FatInfoSector.FreeInfo.NextCluster > (Volume->MaxCluster + 1)) {
if (Volume->FreeInfoValid && (0 < (INT32)(Volume->FatInfoSector.FreeInfo.ClusterCount))) {
Volume->FreeInfoValid = FALSE;
}
FatComputeFreeInfo (Volume);
if (Volume->FatInfoSector.FreeInfo.NextCluster > (Volume->MaxCluster + 1)) {
return (UINTN)FAT_CLUSTER_LAST;
}
}
Cluster = FatGetFatEntry (Volume, Volume->FatInfoSector.FreeInfo.NextCluster);
if (Cluster == FAT_CLUSTER_FREE) {
break;
}
//
// Try the next cluster
//
Volume->FatInfoSector.FreeInfo.NextCluster += 1;
}
Cluster = Volume->FatInfoSector.FreeInfo.NextCluster;
Volume->FatInfoSector.FreeInfo.NextCluster += 1;
return Cluster;
}
/**
Count the number of clusters given a size.
@param Volume - The file system volume.
@param Size - The size in bytes.
@return The number of the clusters.
**/
STATIC
UINTN
FatSizeToClusters (
IN FAT_VOLUME *Volume,
IN UINTN Size
)
{
UINTN Clusters;
Clusters = Size >> Volume->ClusterAlignment;
if ((Size & (Volume->ClusterSize - 1)) > 0) {
Clusters += 1;
}
return Clusters;
}
/**
Shrink the end of the open file base on the file size.
@param OFile - The open file.
@retval EFI_SUCCESS - Shrinked successfully.
@retval EFI_VOLUME_CORRUPTED - There are errors in the file's clusters.
**/
EFI_STATUS
FatShrinkEof (
IN FAT_OFILE *OFile
)
{
FAT_VOLUME *Volume;
UINTN NewSize;
UINTN CurSize;
UINTN Cluster;
UINTN LastCluster;
Volume = OFile->Volume;
ASSERT_VOLUME_LOCKED (Volume);
NewSize = FatSizeToClusters (Volume, OFile->FileSize);
//
// Find the address of the last cluster
//
Cluster = OFile->FileCluster;
LastCluster = FAT_CLUSTER_FREE;
if (NewSize != 0) {
for (CurSize = 0; CurSize < NewSize; CurSize++) {
if ((Cluster == FAT_CLUSTER_FREE) || (Cluster >= FAT_CLUSTER_SPECIAL)) {
DEBUG ((DEBUG_INIT | DEBUG_ERROR, "FatShrinkEof: cluster chain corrupt\n"));
return EFI_VOLUME_CORRUPTED;
}
LastCluster = Cluster;
Cluster = FatGetFatEntry (Volume, Cluster);
}
FatSetFatEntry (Volume, LastCluster, (UINTN)FAT_CLUSTER_LAST);
} else {
//
// Check to see if the file is already completely truncated
//
if (Cluster == FAT_CLUSTER_FREE) {
return EFI_SUCCESS;
}
//
// The file is being completely truncated.
//
OFile->FileCluster = FAT_CLUSTER_FREE;
}
//
// Set CurrentCluster == FileCluster
// to force a recalculation of Position related stuffs
//
OFile->FileCurrentCluster = OFile->FileCluster;
OFile->FileLastCluster = LastCluster;
OFile->Dirty = TRUE;
//
// Free the remaining cluster chain
//
return FatFreeClusters (Volume, Cluster);
}
/**
Grow the end of the open file base on the NewSizeInBytes.
@param OFile - The open file.
@param NewSizeInBytes - The new size in bytes of the open file.
@retval EFI_SUCCESS - The file is grown successfully.
@retval EFI_UNSUPPORTED - The file size is larger than 4GB.
@retval EFI_VOLUME_CORRUPTED - There are errors in the files' clusters.
@retval EFI_VOLUME_FULL - The volume is full and can not grow the file.
**/
EFI_STATUS
FatGrowEof (
IN FAT_OFILE *OFile,
IN UINT64 NewSizeInBytes
)
{
FAT_VOLUME *Volume;
EFI_STATUS Status;
UINTN Cluster;
UINTN CurSize;
UINTN NewSize;
UINTN LastCluster;
UINTN NewCluster;
UINTN ClusterCount;
//
// For FAT file system, the max file is 4GB.
//
if (NewSizeInBytes > 0x0FFFFFFFFL) {
return EFI_UNSUPPORTED;
}
Volume = OFile->Volume;
ASSERT_VOLUME_LOCKED (Volume);
//
// If the file is already large enough, do nothing
//
CurSize = FatSizeToClusters (Volume, OFile->FileSize);
NewSize = FatSizeToClusters (Volume, (UINTN)NewSizeInBytes);
if (CurSize < NewSize) {
//
// If we haven't found the files last cluster do it now
//
if ((OFile->FileCluster != 0) && (OFile->FileLastCluster == 0)) {
Cluster = OFile->FileCluster;
ClusterCount = 0;
while (!FAT_END_OF_FAT_CHAIN (Cluster)) {
if ((Cluster < FAT_MIN_CLUSTER) || (Cluster > Volume->MaxCluster + 1)) {
DEBUG (
(DEBUG_INIT | DEBUG_ERROR,
"FatGrowEof: cluster chain corrupt\n")
);
Status = EFI_VOLUME_CORRUPTED;
goto Done;
}
ClusterCount++;
OFile->FileLastCluster = Cluster;
Cluster = FatGetFatEntry (Volume, Cluster);
}
if (ClusterCount != CurSize) {
DEBUG (
(DEBUG_INIT | DEBUG_ERROR,
"FatGrowEof: cluster chain size does not match file size\n")
);
Status = EFI_VOLUME_CORRUPTED;
goto Done;
}
}
//
// Loop until we've allocated enough space
//
LastCluster = OFile->FileLastCluster;
while (CurSize < NewSize) {
NewCluster = FatAllocateCluster (Volume);
if (FAT_END_OF_FAT_CHAIN (NewCluster)) {
if (LastCluster != FAT_CLUSTER_FREE) {
FatSetFatEntry (Volume, LastCluster, (UINTN)FAT_CLUSTER_LAST);
OFile->FileLastCluster = LastCluster;
}
Status = EFI_VOLUME_FULL;
goto Done;
}
if ((NewCluster < FAT_MIN_CLUSTER) || (NewCluster > Volume->MaxCluster + 1)) {
Status = EFI_VOLUME_CORRUPTED;
goto Done;
}
if (LastCluster != 0) {
FatSetFatEntry (Volume, LastCluster, NewCluster);
} else {
OFile->FileCluster = NewCluster;
OFile->FileCurrentCluster = NewCluster;
}
LastCluster = NewCluster;
CurSize += 1;
//
// Terminate the cluster list
//
// Note that we must do this EVERY time we allocate a cluster, because
// FatAllocateCluster scans the FAT looking for a free cluster and
// "LastCluster" is no longer free! Usually, FatAllocateCluster will
// start looking with the cluster after "LastCluster"; however, when
// there is only one free cluster left, it will find "LastCluster"
// a second time. There are other, less predictable scenarios
// where this could happen, as well.
//
FatSetFatEntry (Volume, LastCluster, (UINTN)FAT_CLUSTER_LAST);
OFile->FileLastCluster = LastCluster;
}
}
OFile->FileSize = (UINTN)NewSizeInBytes;
OFile->Dirty = TRUE;
return EFI_SUCCESS;
Done:
FatShrinkEof (OFile);
return Status;
}
/**
Seek OFile to requested position, and calculate the number of
consecutive clusters from the position in the file
@param OFile - The open file.
@param Position - The file's position which will be accessed.
@param PosLimit - The maximum length current reading/writing may access
@retval EFI_SUCCESS - Set the info successfully.
@retval EFI_VOLUME_CORRUPTED - Cluster chain corrupt.
**/
EFI_STATUS
FatOFilePosition (
IN FAT_OFILE *OFile,
IN UINTN Position,
IN UINTN PosLimit
)
{
FAT_VOLUME *Volume;
UINTN ClusterSize;
UINTN Cluster;
UINTN StartPos;
UINTN Run;
Volume = OFile->Volume;
ClusterSize = Volume->ClusterSize;
ASSERT_VOLUME_LOCKED (Volume);
//
// If this is the fixed root dir, then compute its position
// from its fixed info in the fat bpb
//
if (OFile->IsFixedRootDir) {
OFile->PosDisk = Volume->RootPos + Position;
Run = OFile->FileSize - Position;
} else {
//
// Run the file's cluster chain to find the current position
// If possible, run from the current cluster rather than
// start from beginning
// Assumption: OFile->Position is always consistent with
// OFile->FileCurrentCluster.
// OFile->Position is not modified outside this function;
// OFile->FileCurrentCluster is modified outside this function
// to be the same as OFile->FileCluster
// when OFile->FileCluster is updated, so make a check of this
// and invalidate the original OFile->Position in this case
//
Cluster = OFile->FileCurrentCluster;
StartPos = OFile->Position;
if ((Position < StartPos) || (OFile->FileCluster == Cluster)) {
StartPos = 0;
Cluster = OFile->FileCluster;
}
while (StartPos + ClusterSize <= Position) {
StartPos += ClusterSize;
if ((Cluster == FAT_CLUSTER_FREE) || (Cluster >= FAT_CLUSTER_SPECIAL)) {
DEBUG ((DEBUG_INIT | DEBUG_ERROR, "FatOFilePosition:" " cluster chain corrupt\n"));
return EFI_VOLUME_CORRUPTED;
}
Cluster = FatGetFatEntry (Volume, Cluster);
}
if ((Cluster < FAT_MIN_CLUSTER) || (Cluster > Volume->MaxCluster + 1)) {
return EFI_VOLUME_CORRUPTED;
}
OFile->PosDisk = Volume->FirstClusterPos +
LShiftU64 (Cluster - FAT_MIN_CLUSTER, Volume->ClusterAlignment) +
Position - StartPos;
OFile->FileCurrentCluster = Cluster;
OFile->Position = StartPos;
//
// Compute the number of consecutive clusters in the file
//
Run = StartPos + ClusterSize - Position;
if (!FAT_END_OF_FAT_CHAIN (Cluster)) {
while ((FatGetFatEntry (Volume, Cluster) == Cluster + 1) && Run < PosLimit) {
Run += ClusterSize;
Cluster += 1;
}
}
}
OFile->PosRem = Run;
return EFI_SUCCESS;
}
/**
Get the size of directory of the open file.
@param Volume - The File System Volume.
@param Cluster - The Starting cluster.
@return The physical size of the file starting at the input cluster, if there is error in the
cluster chain, the return value is 0.
**/
UINTN
FatPhysicalDirSize (
IN FAT_VOLUME *Volume,
IN UINTN Cluster
)
{
UINTN Size;
ASSERT_VOLUME_LOCKED (Volume);
//
// Run the cluster chain for the OFile
//
Size = 0;
//
// N.B. ".." directories on some media do not contain a starting
// cluster. In the case of "." or ".." we don't need the size anyway.
//
if (Cluster != 0) {
while (!FAT_END_OF_FAT_CHAIN (Cluster)) {
if ((Cluster == FAT_CLUSTER_FREE) || (Cluster >= FAT_CLUSTER_SPECIAL)) {
DEBUG (
(DEBUG_INIT | DEBUG_ERROR,
"FATDirSize: cluster chain corrupt\n")
);
return 0;
}
Size += Volume->ClusterSize;
Cluster = FatGetFatEntry (Volume, Cluster);
}
}
return Size;
}
/**
Get the physical size of a file on the disk.
@param Volume - The file system volume.
@param RealSize - The real size of a file.
@return The physical size of a file on the disk.
**/
UINT64
FatPhysicalFileSize (
IN FAT_VOLUME *Volume,
IN UINTN RealSize
)
{
UINTN ClusterSizeMask;
UINT64 PhysicalSize;
ClusterSizeMask = Volume->ClusterSize - 1;
PhysicalSize = (RealSize + ClusterSizeMask) & (~((UINT64)ClusterSizeMask));
return PhysicalSize;
}
/**
Update the free cluster info of FatInfoSector of the volume.
@param Volume - FAT file system volume.
**/
VOID
FatComputeFreeInfo (
IN FAT_VOLUME *Volume
)
{
UINTN Index;
//
// If we don't have valid info, compute it now
//
if (!Volume->FreeInfoValid) {
Volume->FreeInfoValid = TRUE;
Volume->FatInfoSector.FreeInfo.ClusterCount = 0;
for (Index = Volume->MaxCluster + 1; Index >= FAT_MIN_CLUSTER; Index--) {
if (Volume->DiskError) {
break;
}
if (FatGetFatEntry (Volume, Index) == FAT_CLUSTER_FREE) {
Volume->FatInfoSector.FreeInfo.ClusterCount += 1;
Volume->FatInfoSector.FreeInfo.NextCluster = (UINT32)Index;
}
}
Volume->FatInfoSector.Signature = FAT_INFO_SIGNATURE;
Volume->FatInfoSector.InfoBeginSignature = FAT_INFO_BEGIN_SIGNATURE;
Volume->FatInfoSector.InfoEndSignature = FAT_INFO_END_SIGNATURE;
}
}
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