GetVolumeLabel.c

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#include <Uefi.h>
 
#include <Guid/FileInfo.h>
#include <Guid/FileSystemVolumeLabelInfo.h>
 
#include <Protocol/SimpleFileSystem.h>
 
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/BaseOverflowLib.h>
#include <Library/DebugLib.h>
#include <Library/DevicePathLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/OcDevicePathLib.h>
#include <Library/OcFileLib.h>
#include <Library/OcStringLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiLib.h>
 
CHAR16 *
OcGetVolumeLabel (
  IN     EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *FileSystem
  )
{
  EFI_STATUS  Status;
 
  EFI_FILE_HANDLE               Volume;
  EFI_FILE_SYSTEM_VOLUME_LABEL  *VolumeInfo;
  UINTN                         VolumeLabelSize;
 
  ASSERT (FileSystem != NULL);
 
  Volume = NULL;
  Status = FileSystem->OpenVolume (
                         FileSystem,
                         &Volume
                         );
 
  if (EFI_ERROR (Status)) {
    return NULL;
  }
 
  VolumeInfo = OcGetFileInfo (
                 Volume,
                 &gEfiFileSystemVolumeLabelInfoIdGuid,
                 sizeof (EFI_FILE_SYSTEM_VOLUME_LABEL),
                 &VolumeLabelSize
                 );
 
  Volume->Close (Volume);
 
  STATIC_ASSERT (
    OFFSET_OF (EFI_FILE_SYSTEM_VOLUME_LABEL, VolumeLabel) == 0,
    "Expected EFI_FILE_SYSTEM_VOLUME_LABEL to represent CHAR16 string!"
    );
 
  if (VolumeInfo != NULL) {
    if ((VolumeLabelSize >= sizeof (CHAR16)) && (VolumeInfo->VolumeLabel[0] != L'\0')) {
      //
      // The spec requires disk label to be NULL-terminated, but it
      // was unclear whether the size should contain terminator or not.
      // Some old HFS Plus drivers provide volume label size without
      // terminating \0 (though they do append it). These drivers must
      // not be used, but we try not to die when debugging is off.
      //
      if (  (VolumeLabelSize > OC_MAX_VOLUME_LABEL_SIZE * sizeof (CHAR16))
         || (VolumeInfo->VolumeLabel[VolumeLabelSize / sizeof (CHAR16) - 1] != '\0'))
      {
        DEBUG ((DEBUG_INFO, "OCFS: Found unterminated or too long volume label!"));
        FreePool (VolumeInfo);
        return AllocateCopyPool (sizeof (L"INVALID"), L"INVALID");
      } else {
        UnicodeFilterString (VolumeInfo->VolumeLabel, TRUE);
        return VolumeInfo->VolumeLabel;
      }
    }
 
    FreePool (VolumeInfo);
  }
 
  return AllocateCopyPool (sizeof (L"NO NAME"), L"NO NAME");
}