Init.c

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#include "Fat.h"
 
EFI_STATUS
FatAllocateVolume (
  IN  EFI_HANDLE             Handle,
  IN  EFI_DISK_IO_PROTOCOL   *DiskIo,
  IN  EFI_DISK_IO2_PROTOCOL  *DiskIo2,
  IN  EFI_BLOCK_IO_PROTOCOL  *BlockIo
  )
{
  EFI_STATUS  Status;
  FAT_VOLUME  *Volume;
 
  //
  // Allocate a volume structure
  //
  Volume = AllocateZeroPool (sizeof (FAT_VOLUME));
  if (Volume == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
 
  //
  // Initialize the structure
  //
  Volume->Signature                  = FAT_VOLUME_SIGNATURE;
  Volume->Handle                     = Handle;
  Volume->DiskIo                     = DiskIo;
  Volume->DiskIo2                    = DiskIo2;
  Volume->BlockIo                    = BlockIo;
  Volume->MediaId                    = BlockIo->Media->MediaId;
  Volume->ReadOnly                   = BlockIo->Media->ReadOnly;
  Volume->VolumeInterface.Revision   = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION;
  Volume->VolumeInterface.OpenVolume = FatOpenVolume;
  InitializeListHead (&Volume->CheckRef);
  InitializeListHead (&Volume->DirCacheList);
  //
  // Initialize Root Directory entry
  //
  Volume->RootDirEnt.FileString       = Volume->RootFileString;
  Volume->RootDirEnt.Entry.Attributes = FAT_ATTRIBUTE_DIRECTORY;
 
  if ((BlockIo == NULL) || (BlockIo->Media == NULL)) {
    DEBUG ((DEBUG_ERROR, "%a BlockIo or BlockIo is NULL!\n", __func__));
    Status = EFI_INVALID_PARAMETER;
    goto Done;
  }
 
  //
  // Check to see if the underlying block device's BlockSize meets what the FAT spec requires
  //
  if ((BlockIo->Media->BlockSize != 512) &&
      (BlockIo->Media->BlockSize != SIZE_1KB) &&
      (BlockIo->Media->BlockSize != SIZE_2KB) &&
      (BlockIo->Media->BlockSize != SIZE_4KB))
  {
    Status = EFI_UNSUPPORTED;
    DEBUG ((
      DEBUG_ERROR,
      "%a invalid BlockIo BlockSize %u for FAT filesystem on MediaId %u. Must be 512B, 1KB, 2KB, or 4KB\n",
      __func__,
      BlockIo->Media->BlockSize,
      BlockIo->Media->MediaId
      ));
    goto Done;
  }
 
  //
  // Check to see if there's a file system on the volume
  //
  Status = FatOpenDevice (Volume);
  if (EFI_ERROR (Status)) {
    goto Done;
  }
 
  //
  // Initialize cache
  //
  Status = FatInitializeDiskCache (Volume);
  if (EFI_ERROR (Status)) {
    goto Done;
  }
 
  //
  // Install our protocol interfaces on the device's handle
  //
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &Volume->Handle,
                  &gEfiSimpleFileSystemProtocolGuid,
                  &Volume->VolumeInterface,
                  NULL
                  );
  if (EFI_ERROR (Status)) {
    goto Done;
  }
 
  //
  // Volume installed
  //
  DEBUG ((DEBUG_INIT, "Installed Fat filesystem on %p\n", Handle));
  Volume->Valid = TRUE;
 
Done:
  if (EFI_ERROR (Status)) {
    FatFreeVolume (Volume);
  }
 
  return Status;
}
 
EFI_STATUS
FatAbandonVolume (
  IN FAT_VOLUME  *Volume
  )
{
  EFI_STATUS  Status;
  BOOLEAN     LockedByMe;
 
  //
  // Uninstall the protocol interface.
  //
  if (Volume->Handle != NULL) {
    Status = gBS->UninstallMultipleProtocolInterfaces (
                    Volume->Handle,
                    &gEfiSimpleFileSystemProtocolGuid,
                    &Volume->VolumeInterface,
                    NULL
                    );
    if (EFI_ERROR (Status)) {
      return Status;
    }
  }
 
  LockedByMe = FALSE;
 
  //
  // Acquire the lock.
  // If the caller has already acquired the lock (which
  // means we are in the process of some Fat operation),
  // we can not acquire again.
  //
  Status = FatAcquireLockOrFail ();
  if (!EFI_ERROR (Status)) {
    LockedByMe = TRUE;
  }
 
  //
  // The volume is still being used. Hence, set error flag for all OFiles still in
  // use. In two cases, we could get here. One is EFI_MEDIA_CHANGED, the other is
  // EFI_NO_MEDIA.
  //
  if (Volume->Root != NULL) {
    FatSetVolumeError (
      Volume->Root,
      Volume->BlockIo->Media->MediaPresent ? EFI_MEDIA_CHANGED : EFI_NO_MEDIA
      );
  }
 
  Volume->Valid = FALSE;
 
  //
  // Release the lock.
  // If locked by me, this means DriverBindingStop is NOT
  // called within an on-going Fat operation, so we should
  // take responsibility to cleanup and free the volume.
  // Otherwise, the DriverBindingStop is called within an on-going
  // Fat operation, we shouldn't check reference, so just let outer
  // FatCleanupVolume do the task.
  //
  if (LockedByMe) {
    FatCleanupVolume (Volume, NULL, EFI_SUCCESS, NULL);
    FatReleaseLock ();
  }
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
FatOpenDevice (
  IN OUT FAT_VOLUME  *Volume
  )
{
  EFI_STATUS            Status;
  UINT32                BlockSize;
  UINT32                DirtyMask;
  EFI_DISK_IO_PROTOCOL  *DiskIo;
  FAT_BOOT_SECTOR       FatBs;
  FAT_VOLUME_TYPE       FatType;
  UINTN                 RootDirSectors;
  UINTN                 FatLba;
  UINTN                 RootLba;
  UINTN                 FirstClusterLba;
  UINTN                 Sectors;
  UINTN                 SectorsPerFat;
  UINT8                 SectorsPerClusterAlignment;
  UINT8                 BlockAlignment;
 
  //
  // Read the FAT_BOOT_SECTOR BPB info
  // This is the only part of FAT code that uses parent DiskIo,
  // Others use FatDiskIo which utilizes a Cache.
  //
  DiskIo = Volume->DiskIo;
  Status = DiskIo->ReadDisk (DiskIo, Volume->MediaId, 0, sizeof (FatBs), &FatBs);
 
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_VERBOSE, "%a: read of part_lba failed %r\n", __func__, Status));
    return Status;
  }
 
  FatType = FatUndefined;
 
  //
  // Use LargeSectors if Sectors is 0
  //
  Sectors = FatBs.FatBsb.Sectors;
  if (Sectors == 0) {
    Sectors = FatBs.FatBsb.LargeSectors;
  }
 
  SectorsPerFat = FatBs.FatBsb.SectorsPerFat;
  if (SectorsPerFat == 0) {
    SectorsPerFat = FatBs.FatBse.Fat32Bse.LargeSectorsPerFat;
    FatType       = Fat32;
  }
 
  //
  // Is boot sector a fat sector?
  // (Note that so far we only know if the sector is FAT32 or not, we don't
  // know if the sector is Fat16 or Fat12 until later when we can compute
  // the volume size)
  //
  if ((FatBs.FatBsb.ReservedSectors == 0) || (FatBs.FatBsb.NumFats == 0) || (Sectors == 0)) {
    return EFI_UNSUPPORTED;
  }
 
  if ((FatBs.FatBsb.SectorSize & (FatBs.FatBsb.SectorSize - 1)) != 0) {
    return EFI_UNSUPPORTED;
  }
 
  BlockAlignment = (UINT8)HighBitSet32 (FatBs.FatBsb.SectorSize);
  if ((BlockAlignment > MAX_BLOCK_ALIGNMENT) || (BlockAlignment < MIN_BLOCK_ALIGNMENT)) {
    return EFI_UNSUPPORTED;
  }
 
  if ((FatBs.FatBsb.SectorsPerCluster & (FatBs.FatBsb.SectorsPerCluster - 1)) != 0) {
    return EFI_UNSUPPORTED;
  }
 
  SectorsPerClusterAlignment = (UINT8)HighBitSet32 (FatBs.FatBsb.SectorsPerCluster);
  if (SectorsPerClusterAlignment > MAX_SECTORS_PER_CLUSTER_ALIGNMENT) {
    return EFI_UNSUPPORTED;
  }
 
  if ((FatBs.FatBsb.Media <= 0xf7) &&
      (FatBs.FatBsb.Media != 0xf0) &&
      (FatBs.FatBsb.Media != 0x00) &&
      (FatBs.FatBsb.Media != 0x01)
      )
  {
    return EFI_UNSUPPORTED;
  }
 
  //
  // Initialize fields the volume information for this FatType
  //
  if (FatType != Fat32) {
    if (FatBs.FatBsb.RootEntries == 0) {
      return EFI_UNSUPPORTED;
    }
 
    //
    // Unpack fat12, fat16 info
    //
    Volume->RootEntries = FatBs.FatBsb.RootEntries;
  } else {
    //
    // If this is fat32, refuse to mount mirror-disabled volumes
    //
    if (((SectorsPerFat == 0) || (FatBs.FatBse.Fat32Bse.FsVersion != 0)) || (FatBs.FatBse.Fat32Bse.ExtendedFlags & 0x80)) {
      return EFI_UNSUPPORTED;
    }
 
    //
    // Unpack fat32 info
    //
    Volume->RootCluster = FatBs.FatBse.Fat32Bse.RootDirFirstCluster;
  }
 
  Volume->NumFats = FatBs.FatBsb.NumFats;
  //
  // Compute some fat locations
  //
  BlockSize      = FatBs.FatBsb.SectorSize;
  RootDirSectors = ((Volume->RootEntries * sizeof (FAT_DIRECTORY_ENTRY)) + (BlockSize - 1)) / BlockSize;
 
  FatLba          = FatBs.FatBsb.ReservedSectors;
  RootLba         = FatBs.FatBsb.NumFats * SectorsPerFat + FatLba;
  FirstClusterLba = RootLba + RootDirSectors;
 
  Volume->FatPos  = FatLba * BlockSize;
  Volume->FatSize = SectorsPerFat * BlockSize;
 
  Volume->VolumeSize       = LShiftU64 (Sectors, BlockAlignment);
  Volume->RootPos          = LShiftU64 (RootLba, BlockAlignment);
  Volume->FirstClusterPos  = LShiftU64 (FirstClusterLba, BlockAlignment);
  Volume->MaxCluster       = (Sectors - FirstClusterLba) >> SectorsPerClusterAlignment;
  Volume->ClusterAlignment = (UINT8)(BlockAlignment + SectorsPerClusterAlignment);
  Volume->ClusterSize      = (UINTN)1 << (Volume->ClusterAlignment);
 
  //
  // If this is not a fat32, determine if it's a fat16 or fat12
  //
  if (FatType != Fat32) {
    if (Volume->MaxCluster >= FAT_MAX_FAT16_CLUSTER) {
      return EFI_VOLUME_CORRUPTED;
    }
 
    FatType = Volume->MaxCluster < FAT_MAX_FAT12_CLUSTER ? Fat12 : Fat16;
    //
    // fat12 & fat16 fat-entries are 2 bytes
    //
    Volume->FatEntrySize = sizeof (UINT16);
    DirtyMask            = FAT16_DIRTY_MASK;
  } else {
    if (Volume->MaxCluster < FAT_MAX_FAT16_CLUSTER) {
      return EFI_VOLUME_CORRUPTED;
    }
 
    //
    // fat32 fat-entries are 4 bytes
    //
    Volume->FatEntrySize = sizeof (UINT32);
    DirtyMask            = FAT32_DIRTY_MASK;
  }
 
  //
  // Get the DirtyValue and NotDirtyValue
  // We should keep the initial value as the NotDirtyValue
  // in case the volume is dirty already
  //
  if (FatType != Fat12) {
    Status = FatAccessVolumeDirty (Volume, ReadDisk, &Volume->NotDirtyValue);
    if (EFI_ERROR (Status)) {
      return Status;
    }
 
    Volume->DirtyValue = Volume->NotDirtyValue & DirtyMask;
  }
 
  //
  // If present, read the fat hint info
  //
  if (FatType == Fat32) {
    Volume->FreeInfoPos = FatBs.FatBse.Fat32Bse.FsInfoSector * BlockSize;
    if (FatBs.FatBse.Fat32Bse.FsInfoSector != 0) {
      FatDiskIo (Volume, ReadDisk, Volume->FreeInfoPos, sizeof (FAT_INFO_SECTOR), &Volume->FatInfoSector, NULL);
      if ((Volume->FatInfoSector.Signature == FAT_INFO_SIGNATURE) &&
          (Volume->FatInfoSector.InfoBeginSignature == FAT_INFO_BEGIN_SIGNATURE) &&
          (Volume->FatInfoSector.InfoEndSignature == FAT_INFO_END_SIGNATURE) &&
          (Volume->FatInfoSector.FreeInfo.ClusterCount <= Volume->MaxCluster)
          )
      {
        Volume->FreeInfoValid = TRUE;
      }
    }
  }
 
  //
  // Just make up a FreeInfo.NextCluster for use by allocate cluster
  //
  if ((FAT_MIN_CLUSTER > Volume->FatInfoSector.FreeInfo.NextCluster) ||
      (Volume->FatInfoSector.FreeInfo.NextCluster > Volume->MaxCluster + 1)
      )
  {
    Volume->FatInfoSector.FreeInfo.NextCluster = FAT_MIN_CLUSTER;
  }
 
  //
  // We are now defining FAT Type
  //
  Volume->FatType = FatType;
  ASSERT (FatType != FatUndefined);
 
  return EFI_SUCCESS;
}