summaryrefslogtreecommitdiff
path: root/ShellPkg/Library/BaseFileHandleLib/BaseFileHandleLib.c
blob: bd3a4a7b52361cfb82926aeae9fdb5c6b772cde9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
/** @file
  Provides interface to EFI_FILE_HANDLE functionality.

  Copyright (c) 2006 - 2010, 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.

**/

#include <Uefi.h>

#include <Protocol/SimpleFileSystem.h>

#include <Guid/FileInfo.h>

#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/FileHandleLib.h>
#include <Library/PcdLib.h>
#include <Library/PrintLib.h>

#define MAX_FILE_NAME_LEN 522 // (20 * (6+5+2))+1) unicode characters from EFI FAT spec (doubled for bytes)
#define FIND_XXXXX_FILE_BUFFER_SIZE (SIZE_OF_EFI_FILE_INFO + MAX_FILE_NAME_LEN)

/**
  This function will retrieve the information about the file for the handle
  specified and store it in allocated pool memory.

  This function allocates a buffer to store the file's information. It is the
  caller's responsibility to free the buffer

  @param  FileHandle  The file handle of the file for which information is
  being requested.

  @retval NULL information could not be retrieved.

  @return the information about the file
**/
EFI_FILE_INFO*
EFIAPI
FileHandleGetInfo (
  IN EFI_FILE_HANDLE            FileHandle
  )
{
  EFI_FILE_INFO   *FileInfo;
  UINTN           FileInfoSize;
  EFI_STATUS      Status;

  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);

  //
  // Get the required size to allocate
  //
  FileInfoSize = 0;
  FileInfo = NULL;
  Status = FileHandle->GetInfo(FileHandle,
                               &gEfiFileInfoGuid,
                               &FileInfoSize,
                               FileInfo);
  //
  // error is expected.  getting size to allocate
  //
  ASSERT (Status == EFI_BUFFER_TOO_SMALL);
  FileInfo = AllocateZeroPool(FileInfoSize);
  ASSERT (FileInfo != NULL);
  //
  // now get the information
  //
  Status = FileHandle->GetInfo(FileHandle,
                               &gEfiFileInfoGuid,
                               &FileInfoSize,
                               FileInfo);
  //
  // if we got an error free the memory and return NULL
  //
  if (EFI_ERROR(Status)) {
    FreePool(FileInfo);
    return NULL;
  }
  return (FileInfo);
}

/**
  This function sets the information about the file for the opened handle
  specified.

  @param[in]  FileHandle        The file handle of the file for which information
                                is being set.

  @param[in]  FileInfo          The information to set.

  @retval EFI_SUCCESS		        The information was set.
  @retval EFI_INVALID_PARAMETER A parameter was out of range or invalid.
  @retval EFI_UNSUPPORTED       The FileHandle does not support FileInfo.
  @retval EFI_NO_MEDIA		      The device has no medium.
  @retval EFI_DEVICE_ERROR	    The device reported an error.
  @retval EFI_VOLUME_CORRUPTED	The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED	  The file or medium is write protected.
  @retval EFI_ACCESS_DENIED     The file was opened read only.
  @retval EFI_VOLUME_FULL       The volume is full.
**/
EFI_STATUS
EFIAPI
FileHandleSetInfo (
  IN EFI_FILE_HANDLE  	        FileHandle,
  IN CONST EFI_FILE_INFO        *FileInfo
  )
{

  //
  // ASSERT if the FileHandle or FileInfo is NULL
  //
  ASSERT (FileHandle != NULL);
  ASSERT (FileInfo   != NULL);

  //
  // Set the info
  //
  return (FileHandle->SetInfo(FileHandle,
                              &gEfiFileInfoGuid,
                              (UINTN)FileInfo->Size,
                              (EFI_FILE_INFO*)FileInfo));
}

/**
  This function reads information from an opened file.

  If FileHandle is not a directory, the function reads the requested number of
  bytes from the file at the file's current position and returns them in Buffer.
  If the read goes beyond the end of the file, the read length is truncated to the
  end of the file. The file's current position is increased by the number of bytes
  returned.  If FileHandle is a directory, the function reads the directory entry
  at the file's current position and returns the entry in Buffer. If the Buffer
  is not large enough to hold the current directory entry, then
  EFI_BUFFER_TOO_SMALL is returned and the current file position is not updated.
  BufferSize is set to be the size of the buffer needed to read the entry. On
  success, the current position is updated to the next directory entry. If there
  are no more directory entries, the read returns a zero-length buffer.
  EFI_FILE_INFO is the structure returned as the directory entry.

  @param FileHandle             the opened file handle
  @param BufferSize             on input the size of buffer in bytes.  on return
                                the number of bytes written.
  @param Buffer                 the buffer to put read data into.

  @retval EFI_SUCCESS           Data was read.
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_BUFFER_TO_SMALL   Buffer is too small. ReadSize contains required
                                size.

**/
EFI_STATUS
EFIAPI
FileHandleRead(
  IN EFI_FILE_HANDLE            FileHandle,
  IN OUT UINTN                  *BufferSize,
  OUT VOID                      *Buffer
  )
{
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);

  //
  // Perform the read based on EFI_FILE_PROTOCOL
  //
  return (FileHandle->Read(FileHandle, BufferSize, Buffer));
}


/**
  Write data to a file.

  This function writes the specified number of bytes to the file at the current
  file position. The current file position is advanced the actual number of bytes
  written, which is returned in BufferSize. Partial writes only occur when there
  has been a data error during the write attempt (such as "volume space full").
  The file is automatically grown to hold the data if required. Direct writes to
  opened directories are not supported.

  @param FileHandle           The opened file for writing
  @param BufferSize           on input the number of bytes in Buffer.  On output
                              the number of bytes written.
  @param Buffer               the buffer containing data to write is stored.

 @retval EFI_SUCCESS	        Data was written.
 @retval EFI_UNSUPPORTED	    Writes to an open directory are not supported.
 @retval EFI_NO_MEDIA	        The device has no media.
 @retval EFI_DEVICE_ERROR	    The device reported an error.
 @retval EFI_VOLUME_CORRUPTED	The file system structures are corrupted.
 @retval EFI_WRITE_PROTECTED	The device is write-protected.
 @retval EFI_ACCESS_DENIED	  The file was open for read only.
 @retval EFI_VOLUME_FULL	    The volume is full.
**/
EFI_STATUS
EFIAPI
FileHandleWrite(
  IN EFI_FILE_HANDLE            FileHandle,
  IN OUT UINTN                  *BufferSize,
  IN VOID                       *Buffer
  )
{
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the write based on EFI_FILE_PROTOCOL
  //
  return (FileHandle->Write(FileHandle, BufferSize, Buffer));
}

/**
  Close an open file handle.

  This function closes a specified file handle. All "dirty" cached file data is
  flushed to the device, and the file is closed. In all cases the handle is
  closed.

@param FileHandle               the file handle to close.

@retval EFI_SUCCESS             the file handle was closed sucessfully.
**/
EFI_STATUS
EFIAPI
FileHandleClose (
  IN EFI_FILE_HANDLE            FileHandle
  )
{
  EFI_STATUS Status;
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the Close based on EFI_FILE_PROTOCOL
  //
  Status = FileHandle->Close(FileHandle);
  return Status;
}

/**
  Delete a file and close the handle

  This function closes and deletes a file. In all cases the file handle is closed.
  If the file cannot be deleted, the warning code EFI_WARN_DELETE_FAILURE is
  returned, but the handle is still closed.

  @param FileHandle             the file handle to delete

  @retval EFI_SUCCESS           the file was closed sucessfully
  @retval EFI_WARN_DELETE_FAILURE the handle was closed, but the file was not
                                deleted
  @retval INVALID_PARAMETER    	One of the parameters has an invalid value.
**/
EFI_STATUS
EFIAPI
FileHandleDelete (
  IN EFI_FILE_HANDLE		FileHandle
  )
{
  EFI_STATUS Status;
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the Delete based on EFI_FILE_PROTOCOL
  //
  Status = FileHandle->Delete(FileHandle);
  return Status;
}

/**
  Set the current position in a file.

  This function sets the current file position for the handle to the position
  supplied. With the exception of seeking to position 0xFFFFFFFFFFFFFFFF, only
  absolute positioning is supported, and seeking past the end of the file is
  allowed (a subsequent write would grow the file). Seeking to position
  0xFFFFFFFFFFFFFFFF causes the current position to be set to the end of the file.
  If FileHandle is a directory, the only position that may be set is zero. This
  has the effect of starting the read process of the directory entries over.

  @param FileHandle             The file handle on which the position is being set
  @param Position               Byte position from begining of file

  @retval EFI_SUCCESS           Operation completed sucessfully.
  @retval EFI_UNSUPPORTED       the seek request for non-zero is not valid on
                                directories.
  @retval INVALID_PARAMETER     One of the parameters has an invalid value.
**/
EFI_STATUS
EFIAPI
FileHandleSetPosition (
  IN EFI_FILE_HANDLE   	FileHandle,
  IN UINT64           	Position
  )
{
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the SetPosition based on EFI_FILE_PROTOCOL
  //
  return (FileHandle->SetPosition(FileHandle, Position));
}

/**
  Gets a file's current position

  This function retrieves the current file position for the file handle. For
  directories, the current file position has no meaning outside of the file
  system driver and as such the operation is not supported. An error is returned
  if FileHandle is a directory.

  @param FileHandle             The open file handle on which to get the position.
  @param Position               Byte position from begining of file.

  @retval EFI_SUCCESS           the operation completed sucessfully.
  @retval INVALID_PARAMETER     One of the parameters has an invalid value.
  @retval EFI_UNSUPPORTED       the request is not valid on directories.
**/
EFI_STATUS
EFIAPI
FileHandleGetPosition (
  IN EFI_FILE_HANDLE            FileHandle,
  OUT UINT64                    *Position
  )
{
  if (Position == NULL) {
    return (EFI_INVALID_PARAMETER);
  }
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the GetPosition based on EFI_FILE_PROTOCOL
  //
  return (FileHandle->GetPosition(FileHandle, Position));
}
/**
  Flushes data on a file

  This function flushes all modified data associated with a file to a device.

  @param FileHandle             The file handle on which to flush data

  @retval EFI_SUCCESS           The data was flushed.
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @retval EFI_WRITE_PROTECTED   The file or medium is write protected.
  @retval EFI_ACCESS_DENIED     The file was opened for read only.
**/
EFI_STATUS
EFIAPI
FileHandleFlush (
  IN EFI_FILE_HANDLE            FileHandle
  )
{
  //
  // ASSERT if FileHandle is NULL
  //
  ASSERT (FileHandle != NULL);
  //
  // Perform the Flush based on EFI_FILE_PROTOCOL
  //
  return (FileHandle->Flush(FileHandle));
}

/**
  function to determine if a given handle is a directory handle

  if DirHandle is NULL then ASSERT()

  open the file information on the DirHandle and verify that the Attribute
  includes EFI_FILE_DIRECTORY bit set.

  @param DirHandle              Handle to open file

  @retval EFI_SUCCESS           DirHandle is a directory
  @retval EFI_INVALID_PARAMETER DirHandle did not have EFI_FILE_INFO available
  @retval EFI_NOT_FOUND         DirHandle is not a directory
**/
EFI_STATUS
EFIAPI
FileHandleIsDirectory (
  IN EFI_FILE_HANDLE            DirHandle
  )
{
  EFI_FILE_INFO *DirInfo;

  //
  // ASSERT if DirHandle is NULL
  //
  ASSERT(DirHandle != NULL);

  //
  // get the file information for DirHandle
  //
  DirInfo = FileHandleGetInfo (DirHandle);

  //
  // Parse DirInfo
  //
  if (DirInfo == NULL) {
    //
    // We got nothing...
    //
    return (EFI_INVALID_PARAMETER);
  }
  if ((DirInfo->Attribute & EFI_FILE_DIRECTORY) == 0) {
    //
    // Attributes say this is not a directory
    //
    FreePool (DirInfo);
    return (EFI_NOT_FOUND);
  }
  //
  // all good...
  //
  FreePool (DirInfo);
  return (EFI_SUCCESS);
}

/**
  Retrieves the first file from a directory

  This function opens a directory and gets the first file's info in the
  directory. Caller can use FileHandleFindNextFile() to get other files.  When
  complete the caller is responsible for calling FreePool() on Buffer.

  @param DirHandle              The file handle of the directory to search
  @param Buffer                 Pointer to buffer for file's information

  @retval EFI_SUCCESS           Found the first file.
  @retval EFI_NOT_FOUND         Cannot find the directory.
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
  @return Others                status of FileHandleGetInfo, FileHandleSetPosition,
                                or FileHandleRead
**/
EFI_STATUS
EFIAPI
FileHandleFindFirstFile (
  IN EFI_FILE_HANDLE            DirHandle,
  OUT EFI_FILE_INFO             **Buffer
  )
{
  EFI_STATUS    Status;
  UINTN         BufferSize;

  //
  // ASSERTs
  //
  ASSERT (DirHandle != NULL);
  ASSERT (Buffer != NULL);

  //
  // verify that DirHandle is a directory
  //
  Status = FileHandleIsDirectory(DirHandle);
  if (EFI_ERROR(Status)) {
    return (Status);
  }

  //
  // reset to the begining of the directory
  //
  Status = FileHandleSetPosition(DirHandle, 0);
  if (EFI_ERROR(Status)) {
    return (Status);
  }

  //
  // Allocate a buffer sized to struct size + enough for the string at the end
  //
  BufferSize = FIND_XXXXX_FILE_BUFFER_SIZE;
  *Buffer = AllocateZeroPool(BufferSize);
  ASSERT (*Buffer != NULL);

  //
  // read in the info about the first file
  //
  Status = FileHandleRead (DirHandle, &BufferSize, *Buffer);
  ASSERT(Status != EFI_BUFFER_TOO_SMALL);
  if (EFI_ERROR(Status)) {
    FreePool(*Buffer);
    *Buffer = NULL;
    return (Status);
  }
  return (EFI_SUCCESS);
}
/**
  Retrieves the next file in a directory.

  To use this function, caller must call the FileHandleFindFirstFile() to get the
  first file, and then use this function get other files. This function can be
  called for several times to get each file's information in the directory. If
  the call of FileHandleFindNextFile() got the last file in the directory, the next
  call of this function has no file to get. *NoFile will be set to TRUE and the
  Buffer memory will be automatically freed.

  @param DirHandle              the file handle of the directory
  @param Buffer			            pointer to buffer for file's information
  @param NoFile			            pointer to boolean when last file is found

  @retval EFI_SUCCESS           Found the next file, or reached last file
  @retval EFI_NO_MEDIA          The device has no media.
  @retval EFI_DEVICE_ERROR      The device reported an error.
  @retval EFI_VOLUME_CORRUPTED  The file system structures are corrupted.
**/
EFI_STATUS
EFIAPI
FileHandleFindNextFile(
  IN EFI_FILE_HANDLE             DirHandle,
  OUT EFI_FILE_INFO              *Buffer,
  OUT BOOLEAN                    *NoFile
  )
{
  EFI_STATUS    Status;
  UINTN         BufferSize;

  //
  // ASSERTs for DirHandle or Buffer or NoFile poitners being NULL
  //
  ASSERT (DirHandle != NULL);
  ASSERT (Buffer    != NULL);
  ASSERT (NoFile    != NULL);

  //
  // This BufferSize MUST stay equal to the originally allocated one in GetFirstFile
  //
  BufferSize = FIND_XXXXX_FILE_BUFFER_SIZE;

  //
  // read in the info about the next file
  //
  Status = FileHandleRead (DirHandle, &BufferSize, Buffer);
  ASSERT(Status != EFI_BUFFER_TOO_SMALL);
  if (EFI_ERROR(Status)) {
    return (Status);
  }

  //
  // If we read 0 bytes (but did not have erros) we already read in the last file.
  //
  if (BufferSize == 0) {
    FreePool(Buffer);
    *NoFile = TRUE;
  }

  return (EFI_SUCCESS);
}

/**
  Retrieve the size of a file.

  if FileHandle is NULL then ASSERT()
  if Size is NULL then ASSERT()

  This function extracts the file size info from the FileHandle's EFI_FILE_INFO
  data.

  @param FileHandle             file handle from which size is retrieved
  @param Size                   pointer to size

  @retval EFI_SUCCESS           operation was completed sucessfully
  @retval EFI_DEVICE_ERROR      cannot access the file
**/
EFI_STATUS
EFIAPI
FileHandleGetSize (
  IN EFI_FILE_HANDLE            FileHandle,
  OUT UINT64                    *Size
  )
{
  EFI_FILE_INFO                 *FileInfo;

  //
  // ASSERT for FileHandle or Size being NULL
  //
  ASSERT (FileHandle != NULL);
  ASSERT (Size != NULL);

  //
  // get the FileInfo structure
  //
  FileInfo = FileHandleGetInfo(FileHandle);
  if (FileInfo == NULL) {
    return (EFI_DEVICE_ERROR);
  }

  //
  // Assign the Size pointer to the correct value
  //
  *Size = FileInfo->FileSize;

  //
  // free the FileInfo memory
  //
  FreePool(FileInfo);

  return (EFI_SUCCESS);
}

/**
  Set the size of a file.

  If FileHandle is NULL then ASSERT().

  This function changes the file size info from the FileHandle's EFI_FILE_INFO
  data.

  @param FileHandle             File handle whose size is to be changed.
  @param Size                   New size.

  @retval EFI_SUCCESS           operation was completed sucessfully.
  @retval EFI_DEVICE_ERROR      cannot access the file.
**/
EFI_STATUS
EFIAPI
FileHandleSetSize (
  IN EFI_FILE_HANDLE            FileHandle,
  IN UINT64                     Size
  )
{
  EFI_FILE_INFO                 *FileInfo;
  EFI_STATUS                    Status;

  //
  // ASSERT for FileHandle or Size being NULL
  //
  ASSERT (FileHandle != NULL);

  //
  // get the FileInfo structure
  //
  FileInfo = FileHandleGetInfo(FileHandle);
  if (FileInfo == NULL) {
    return (EFI_DEVICE_ERROR);
  }

  //
  // Assign the FileSize pointer to the new value
  //
  FileInfo->FileSize = Size;

  Status = FileHandleSetInfo(FileHandle, FileInfo);
  //
  // free the FileInfo memory
  //
  FreePool(FileInfo);

  return (Status);
}

/**
  Safely append (on the left) with automatic string resizing given length of Destination and
  desired length of copy from Source.

  append the first D characters of Source to the end of Destination, where D is
  the lesser of Count and the StrLen() of Source. If appending those D characters
  will fit within Destination (whose Size is given as CurrentSize) and
  still leave room for a NULL terminator, then those characters are appended,
  starting at the original terminating NULL of Destination, and a new terminating
  NULL is appended.

  If appending D characters onto Destination will result in a overflow of the size
  given in CurrentSize the string will be grown such that the copy can be performed
  and CurrentSize will be updated to the new size.

  If Source is NULL, there is nothing to append, just return the current buffer in
  Destination.

  if Destination is NULL, then ASSERT()
  if Destination's current length (including NULL terminator) is already more then
  CurrentSize, then ASSERT()

  @param[in,out] Destination   The String to append onto
  @param[in,out] CurrentSize   on call the number of bytes in Destination.  On
                                return possibly the new size (still in bytes).  if NULL
                                then allocate whatever is needed.
  @param[in]      Source        The String to append from
  @param[in]      Count         Maximum number of characters to append.  if 0 then
                                all are appended.

  @return Destination           return the resultant string.
**/
CHAR16*
EFIAPI
StrnCatGrowLeft (
  IN OUT CHAR16           **Destination,
  IN OUT UINTN            *CurrentSize,
  IN     CONST CHAR16     *Source,
  IN     UINTN            Count
  )
{
  UINTN DestinationStartSize;
  UINTN NewSize;
  UINTN CopySize;

  //
  // ASSERTs
  //
  ASSERT(Destination != NULL);

  //
  // If there's nothing to do then just return Destination
  //
  if (Source == NULL) {
    return (*Destination);
  }

  //
  // allow for NULL pointers address as Destination
  //
  if (*Destination != NULL) {
    ASSERT(CurrentSize != 0);
    DestinationStartSize = StrSize(*Destination);
    ASSERT(DestinationStartSize <= *CurrentSize);
  } else {
    DestinationStartSize = 0;
//    ASSERT(*CurrentSize == 0);
  }

  //
  // Append all of Source?
  //
  if (Count == 0) {
    Count = StrSize(Source);
  }

  //
  // Test and grow if required
  //
  if (CurrentSize != NULL) {
    NewSize = *CurrentSize;
    while (NewSize < (DestinationStartSize + Count)) {
      NewSize += 2 * Count;
    }
    *Destination = ReallocatePool(*CurrentSize, NewSize, *Destination);
    *CurrentSize = NewSize;
  } else {
    *Destination = AllocateZeroPool(Count+sizeof(CHAR16));
  }

  CopySize = StrSize(*Destination);
  CopyMem((*Destination)+((Count-2)/sizeof(CHAR16)), *Destination, CopySize);
  CopyMem(*Destination, Source, Count-2);
  return (*Destination);
}

/**
  Function to get a full filename given a EFI_FILE_HANDLE somewhere lower on the
  directory 'stack'.

  if Handle is NULL, return EFI_INVALID_PARAMETER

  @param[in] Handle             Handle to the Directory or File to create path to.
  @param[out] FullFileName      pointer to pointer to generated full file name.  It
                                is the responsibility of the caller to free this memory
                                with a call to FreePool().
  @retval EFI_SUCCESS           the operation was sucessful and the FullFileName is valid.
  @retval EFI_INVALID_PARAMETER Handle was NULL.
  @retval EFI_INVALID_PARAMETER FullFileName was NULL.
  @retval EFI_OUT_OF_RESOURCES  a memory allocation failed.
**/
EFI_STATUS
EFIAPI
FileHandleGetFileName (
  IN CONST EFI_FILE_HANDLE      Handle,
  OUT CHAR16                    **FullFileName
  )
{
  EFI_STATUS      Status;
  UINTN           Size;
  EFI_FILE_HANDLE CurrentHandle;
  EFI_FILE_HANDLE NextHigherHandle;
  EFI_FILE_INFO   *FileInfo;

  Size = 0;

  //
  // Check our parameters
  //
  if (FullFileName == NULL || Handle == NULL) {
    return (EFI_INVALID_PARAMETER);
  }

  *FullFileName = NULL;
  CurrentHandle = NULL;

  Status = Handle->Open(Handle, &CurrentHandle, L".", EFI_FILE_MODE_READ, 0);
  if (!EFI_ERROR(Status)) {
    //
    // Reverse out the current directory on the device
    //
    for (;;) {
      FileInfo = FileHandleGetInfo(CurrentHandle);
      if (FileInfo == NULL) {
        Status = EFI_OUT_OF_RESOURCES;
        break;
      } else {
        //
        // We got info... do we have a name? if yes preceed the current path with it...
        //
        if (StrLen (FileInfo->FileName) == 0) {
          if (*FullFileName == NULL) {
            ASSERT((*FullFileName == NULL && Size == 0) || (*FullFileName != NULL));
            *FullFileName = StrnCatGrowLeft(FullFileName, &Size, L"\\", 0);
          }
          FreePool(FileInfo);
          break;
        } else {
          if (*FullFileName == NULL) {
            ASSERT((*FullFileName == NULL && Size == 0) || (*FullFileName != NULL));
            *FullFileName = StrnCatGrowLeft(FullFileName, &Size, L"\\", 0);
          }
          ASSERT((*FullFileName == NULL && Size == 0) || (*FullFileName != NULL));
          *FullFileName = StrnCatGrowLeft(FullFileName, &Size, FileInfo->FileName, 0);
          *FullFileName = StrnCatGrowLeft(FullFileName, &Size, L"\\", 0);
          FreePool(FileInfo);
        }
      }
      //
      // Move to the parent directory
      //
      Status = CurrentHandle->Open (CurrentHandle, &NextHigherHandle, L"..", EFI_FILE_MODE_READ, 0);
      if (EFI_ERROR (Status)) {
        break;
      }

      FileHandleClose(CurrentHandle);
      CurrentHandle = NextHigherHandle;
    }
  } else if (Status == EFI_NOT_FOUND) {
    Status = EFI_SUCCESS;
    ASSERT((*FullFileName == NULL && Size == 0) || (*FullFileName != NULL));
    *FullFileName = StrnCatGrowLeft(FullFileName, &Size, L"\\", 0);
  }

  if (CurrentHandle != NULL) {
    CurrentHandle->Close (CurrentHandle);
  }

  if (EFI_ERROR(Status) && *FullFileName != NULL) {
    FreePool(*FullFileName);
  }

  return (Status);
}

/**
  Function to read a single line from a file. The \n is not included in the returned
  buffer.  The returned buffer must be callee freed.

  If the position upon start is 0, then the Ascii Boolean will be set.  This should be
  maintained and not changed for all operations with the same file.

  @param[in]      Handle        FileHandle to read from.
  @param[in,out]  Ascii         Boolean value for indicating whether the file is Ascii (TRUE) or UCS2 (FALSE);

  @return                       The line of text from the file.

  @sa FileHandleReadLine
**/
CHAR16*
EFIAPI
FileHandleReturnLine(
  IN EFI_FILE_HANDLE            Handle,
  IN OUT BOOLEAN                *Ascii
  )
{
  CHAR16          *RetVal;
  UINTN           Size;
  EFI_STATUS      Status;

  Size = 0;
  RetVal = NULL;

  Status = FileHandleReadLine(Handle, RetVal, &Size, FALSE, Ascii);
  if (Status == EFI_BUFFER_TOO_SMALL) {
    RetVal = AllocatePool(Size);
    Status = FileHandleReadLine(Handle, RetVal, &Size, FALSE, Ascii);
  }
  ASSERT_EFI_ERROR(Status);
  if (EFI_ERROR(Status) && (RetVal != NULL)) {
    FreePool(RetVal);
    RetVal = NULL;
  }
  return (RetVal);
}

/**
  Function to read a single line (up to but not including the \n) from a EFI_FILE_HANDLE.

  If the position upon start is 0, then the Ascii Boolean will be set.  This should be
  maintained and not changed for all operations with the same file.

  @param[in]      Handle        FileHandle to read from
  @param[in,out]  Buffer        pointer to buffer to read into
  @param[in,out]  Size          pointer to number of bytes in buffer
  @param[in]      Truncate      if TRUE then allows for truncation of the line to fit.
                                if FALSE will reset the position to the begining of the
                                line if the buffer is not large enough.
  @param[in,out]  Ascii         Boolean value for indicating whether the file is Ascii (TRUE) or UCS2 (FALSE);

  @retval EFI_SUCCESS           the operation was sucessful.  the line is stored in
                                Buffer.
  @retval EFI_INVALID_PARAMETER Handle was NULL.
  @retval EFI_INVALID_PARAMETER Size was NULL.
  @retval EFI_BUFFER_TOO_SMALL  Size was not enough space to store the line.
                                Size was updated to minimum space required.
  @sa FileHandleRead
**/
EFI_STATUS
EFIAPI
FileHandleReadLine(
  IN EFI_FILE_HANDLE            Handle,
  IN OUT CHAR16                 *Buffer,
  IN OUT UINTN                  *Size,
  IN BOOLEAN                    Truncate,
  IN OUT BOOLEAN                *Ascii
  )
{
  EFI_STATUS  Status;
  CHAR16      CharBuffer;
  UINTN       CharSize;
  UINTN       CountSoFar;
  UINT64      OriginalFilePosition;


  if (Handle == NULL
    ||Size   == NULL
   ){
    return (EFI_INVALID_PARAMETER);
  }
  if (Buffer == NULL) {
    ASSERT(*Size == 0);
  } else {
    *Buffer = CHAR_NULL;
  }
  FileHandleGetPosition(Handle, &OriginalFilePosition);
  if (OriginalFilePosition == 0) {
    CharSize = sizeof(CHAR16);
    Status = FileHandleRead(Handle, &CharSize, &CharBuffer);
    ASSERT_EFI_ERROR(Status);
    if (CharBuffer == UnicodeFileTag) {
      *Ascii = FALSE;
    } else {
      *Ascii = TRUE;
      FileHandleSetPosition(Handle, OriginalFilePosition);
    }
  }

  for (CountSoFar = 0;;CountSoFar++){
    CharBuffer = 0;
    if (*Ascii) {
      CharSize = sizeof(CHAR8);
    } else {
      CharSize = sizeof(CHAR16);
    }
    Status = FileHandleRead(Handle, &CharSize, &CharBuffer);
    if (  EFI_ERROR(Status)
       || CharSize == 0
       || (CharBuffer == L'\n' && !(*Ascii))
       || (CharBuffer ==  '\n' && *Ascii)
     ){
      break;
    }
    //
    // if we have space save it...
    //
    if ((CountSoFar+1)*sizeof(CHAR16) < *Size){
      ASSERT(Buffer != NULL);
      ((CHAR16*)Buffer)[CountSoFar] = CharBuffer;
      ((CHAR16*)Buffer)[CountSoFar+1] = CHAR_NULL;
    }
  }

  //
  // if we ran out of space tell when...
  //
  if ((CountSoFar+1)*sizeof(CHAR16) > *Size){
    *Size = (CountSoFar+1)*sizeof(CHAR16);
    if (!Truncate) {
      FileHandleSetPosition(Handle, OriginalFilePosition);
    } else {
      DEBUG((DEBUG_WARN, "The line was truncated in FileHandleReadLine"));
    }
    return (EFI_BUFFER_TOO_SMALL);
  }
  while(Buffer[StrLen(Buffer)-1] == L'\r') {
    Buffer[StrLen(Buffer)-1] = CHAR_NULL;
  }

  return (Status);
}

/**
  function to write a line of unicode text to a file.

  if Handle is NULL, ASSERT.
  if Buffer is NULL, do nothing.  (return SUCCESS)

  @param[in]     Handle         FileHandle to write to
  @param[in]     Buffer         Buffer to write

  @retval  EFI_SUCCESS          the data was written.
  @retval  other                failure.

  @sa FileHandleWrite
**/
EFI_STATUS
EFIAPI
FileHandleWriteLine(
  IN EFI_FILE_HANDLE Handle,
  IN CHAR16          *Buffer
  )
{
  EFI_STATUS Status;
  UINTN      Size;

  ASSERT(Handle != NULL);

  if (Buffer == NULL) {
    return (EFI_SUCCESS);
  }

  Size = StrSize(Buffer) - sizeof(Buffer[0]);
  Status = FileHandleWrite(Handle, &Size, Buffer);
  if (EFI_ERROR(Status)) {
    return (Status);
  }
  Size = StrSize(L"\r\n") - sizeof(CHAR16);
  return FileHandleWrite(Handle, &Size, L"\r\n");
}

/**
  function to take a formatted argument and print it to a file.

  @param[in] Handle   the file handle for the file to write to
  @param[in] Format   the format argument (see printlib for format specifier)
  @param[in] ...      the variable arguments for the format

  @retval EFI_SUCCESS the operation was sucessful
  @return other       a return value from FileHandleWriteLine

  @sa FileHandleWriteLine
**/
EFI_STATUS
EFIAPI
FileHandlePrintLine(
  IN EFI_FILE_HANDLE  Handle,
  IN CONST CHAR16     *Format,
  ...
  )
{
  VA_LIST           Marker;
  CHAR16            *Buffer;
  EFI_STATUS        Status;

  VA_START (Marker, Format);

  //
  // Get a buffer to print into
  //
  Buffer = AllocateZeroPool (PcdGet16 (PcdShellPrintBufferSize));
  ASSERT (Buffer != NULL);

  //
  // Print into our buffer
  //
  UnicodeVSPrint (Buffer, PcdGet16 (PcdShellPrintBufferSize), Format, Marker);

  //
  // Print buffer into file
  //
  Status = FileHandleWriteLine(Handle, Buffer);

  //
  // Cleanup and return
  //
  FreePool(Buffer);
  return (Status);
}

/**
  Function to determine if a FILE_HANDLE is at the end of the file.

  This will NOT work on directories.

  If Handle is NULL, then ASSERT.

  @param[in] Handle     the file handle

  @retval TRUE          the position is at the end of the file
  @retval FALSE         the position is not at the end of the file
**/
BOOLEAN
EFIAPI
FileHandleEof(
  IN EFI_FILE_HANDLE Handle
  )
{
  EFI_FILE_INFO *Info;
  UINT64        Pos;
  BOOLEAN       RetVal;

  //
  // ASSERT if Handle is NULL
  //
  ASSERT(Handle != NULL);

  FileHandleGetPosition(Handle, &Pos);
  Info = FileHandleGetInfo (Handle);
  ASSERT(Info != NULL);
  FileHandleSetPosition(Handle, Pos);

  if (Info == NULL) {
    return (FALSE);
  }

  if (Pos == Info->FileSize) {
    RetVal = TRUE;
  } else {
    RetVal = FALSE;
  }

  FreePool (Info);

  return (RetVal);
}