summaryrefslogtreecommitdiff
path: root/coreutils/md5sum.c
blob: a9bbdef369f1c0b3b344f112a3bdde72d41bc466 (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
/* md5sum.c - Compute MD5 checksum of files or strings according to the
 *            definition of MD5 in RFC 1321 from April 1992.
 * Copyright (C) 1995-1999 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu> */
/* Hacked to work with BusyBox by Alfred M. Szmidt <ams@trillian.itslinux.org> */

#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <getopt.h>
#include "busybox.h"

/* For some silly reason, this file uses backwards TRUE and FALSE conventions */
#undef TRUE
#undef FALSE
#define FALSE   ((int) 1)
#define TRUE    ((int) 0)

//----------------------------------------------------------------------------
//--------md5.c
//----------------------------------------------------------------------------

/* md5.c - Functions to compute MD5 message digest of files or memory blocks
 *         according to the definition of MD5 in RFC 1321 from April 1992.
 * Copyright (C) 1995, 1996 Free Software Foundation, Inc.
 *
 * NOTE: The canonical source of this file is maintained with the GNU C
 * Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.  */

#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <endian.h>

#include "busybox.h"
//----------------------------------------------------------------------------
//--------md5.h
//----------------------------------------------------------------------------

/* md5.h - Declaration of functions and data types used for MD5 sum
   computing library functions.
   Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   NOTE: The canonical source of this file is maintained with the GNU C
   Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.

   This program is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2, or (at your option) any
   later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifndef _MD5_H
static const int _MD5_H = 1;

#include <stdio.h>

#if defined HAVE_LIMITS_H || defined _LIBC
# include <limits.h>
#endif

/* The following contortions are an attempt to use the C preprocessor
   to determine an unsigned integral type that is 32 bits wide.  An
   alternative approach is to use autoconf's AC_CHECK_SIZEOF macro, but
   doing that would require that the configure script compile and *run*
   the resulting executable.  Locally running cross-compiled executables
   is usually not possible.  */

# include <sys/types.h>
typedef u_int32_t md5_uint32;

/* Structure to save state of computation between the single steps.  */
struct md5_ctx
{
  md5_uint32 A;
  md5_uint32 B;
  md5_uint32 C;
  md5_uint32 D;

  md5_uint32 total[2];
  md5_uint32 buflen;
  char buffer[128];
};

/*
 * The following three functions are build up the low level used in
 * the functions `md5_stream' and `md5_buffer'.
 */

/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
extern void md5_init_ctx __P ((struct md5_ctx *ctx));

/* Starting with the result of former calls of this function (or the
   initialization function update the context for the next LEN bytes
   starting at BUFFER.
   It is necessary that LEN is a multiple of 64!!! */
extern void md5_process_block __P ((const void *buffer, size_t len,
				    struct md5_ctx *ctx));

/* Starting with the result of former calls of this function (or the
   initialization function update the context for the next LEN bytes
   starting at BUFFER.
   It is NOT required that LEN is a multiple of 64.  */
extern void md5_process_bytes __P ((const void *buffer, size_t len,
				    struct md5_ctx *ctx));

/* Process the remaining bytes in the buffer and put result from CTX
   in first 16 bytes following RESBUF.  The result is always in little
   endian byte order, so that a byte-wise output yields to the wanted
   ASCII representation of the message digest.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
extern void *md5_finish_ctx __P ((struct md5_ctx *ctx, void *resbuf));


/* Put result from CTX in first 16 bytes following RESBUF.  The result is
   always in little endian byte order, so that a byte-wise output yields
   to the wanted ASCII representation of the message digest.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
extern void *md5_read_ctx __P ((const struct md5_ctx *ctx, void *resbuf));


/* Compute MD5 message digest for bytes read from STREAM.  The
   resulting message digest number will be written into the 16 bytes
   beginning at RESBLOCK.  */
extern int md5_stream __P ((FILE *stream, void *resblock));

/* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
   result is always in little endian byte order, so that a byte-wise
   output yields to the wanted ASCII representation of the message
   digest.  */
extern void *md5_buffer __P ((const char *buffer, size_t len, void *resblock));

#endif

//----------------------------------------------------------------------------
//--------end of md5.h
//----------------------------------------------------------------------------

/* Handle endian-ness */
#if __BYTE_ORDER == __LITTLE_ENDIAN
	#define SWAP(n) (n)
#else
	#define SWAP(n) ((n << 24) | ((n&65280)<<8) | ((n&16711680)>>8) | (n>>24))
#endif



/* This array contains the bytes used to pad the buffer to the next
   64-byte boundary.  (RFC 1321, 3.1: Step 1)  */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ...  */  };

/* Initialize structure containing state of computation.
   (RFC 1321, 3.3: Step 3)  */
void md5_init_ctx(struct md5_ctx *ctx)
{
  ctx->A = 0x67452301;
  ctx->B = 0xefcdab89;
  ctx->C = 0x98badcfe;
  ctx->D = 0x10325476;

  ctx->total[0] = ctx->total[1] = 0;
  ctx->buflen = 0;
}

/* Put result from CTX in first 16 bytes following RESBUF.  The result
   must be in little endian byte order.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
void *md5_read_ctx(const struct md5_ctx *ctx, void *resbuf)
{
  ((md5_uint32 *) resbuf)[0] = SWAP(ctx->A);
  ((md5_uint32 *) resbuf)[1] = SWAP(ctx->B);
  ((md5_uint32 *) resbuf)[2] = SWAP(ctx->C);
  ((md5_uint32 *) resbuf)[3] = SWAP(ctx->D);

  return resbuf;
}

/* Process the remaining bytes in the internal buffer and the usual
   prolog according to the standard and write the result to RESBUF.

   IMPORTANT: On some systems it is required that RESBUF is correctly
   aligned for a 32 bits value.  */
void *md5_finish_ctx(struct md5_ctx *ctx, void *resbuf)
{
  /* Take yet unprocessed bytes into account.  */
  md5_uint32 bytes = ctx->buflen;
  size_t pad;

  /* Now count remaining bytes.  */
  ctx->total[0] += bytes;
  if (ctx->total[0] < bytes)
    ++ctx->total[1];

  pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
  memcpy(&ctx->buffer[bytes], fillbuf, pad);

  /* Put the 64-bit file length in *bits* at the end of the buffer.  */
  *(md5_uint32 *) & ctx->buffer[bytes + pad] = SWAP(ctx->total[0] << 3);
  *(md5_uint32 *) & ctx->buffer[bytes + pad + 4] =
    SWAP((ctx->total[1] << 3) | (ctx->total[0] >> 29));

  /* Process last bytes.  */
  md5_process_block(ctx->buffer, bytes + pad + 8, ctx);

  return md5_read_ctx(ctx, resbuf);
}

/* Compute MD5 message digest for bytes read from STREAM.  The
   resulting message digest number will be written into the 16 bytes
   beginning at RESBLOCK.  */
int md5_stream(FILE *stream, void *resblock)
{
  /* Important: BLOCKSIZE must be a multiple of 64.  */
static const int BLOCKSIZE = 4096;
  struct md5_ctx ctx;
  char buffer[BLOCKSIZE + 72];
  size_t sum;

  /* Initialize the computation context.  */
  md5_init_ctx(&ctx);

  /* Iterate over full file contents.  */
  while (1) {
    /* We read the file in blocks of BLOCKSIZE bytes.  One call of the
       computation function processes the whole buffer so that with the
       next round of the loop another block can be read.  */
    size_t n;
    sum = 0;

    /* Read block.  Take care for partial reads.  */
    do {
      n = fread(buffer + sum, 1, BLOCKSIZE - sum, stream);

      sum += n;
    }
    while (sum < BLOCKSIZE && n != 0);
    if (n == 0 && ferror(stream))
      return 1;

    /* If end of file is reached, end the loop.  */
    if (n == 0)
      break;

    /* Process buffer with BLOCKSIZE bytes.  Note that
       BLOCKSIZE % 64 == 0
    */
    md5_process_block(buffer, BLOCKSIZE, &ctx);
  }

  /* Add the last bytes if necessary.  */
  if (sum > 0)
    md5_process_bytes(buffer, sum, &ctx);

  /* Construct result in desired memory.  */
  md5_finish_ctx(&ctx, resblock);
  return 0;
}

/* Compute MD5 message digest for LEN bytes beginning at BUFFER.  The
   result is always in little endian byte order, so that a byte-wise
   output yields to the wanted ASCII representation of the message
   digest.  */
void *md5_buffer(const char *buffer, size_t len, void *resblock)
{
  struct md5_ctx ctx;

  /* Initialize the computation context.  */
  md5_init_ctx(&ctx);

  /* Process whole buffer but last len % 64 bytes.  */
  md5_process_bytes(buffer, len, &ctx);

  /* Put result in desired memory area.  */
  return md5_finish_ctx(&ctx, resblock);
}

void md5_process_bytes(const void *buffer, size_t len, struct md5_ctx *ctx)
{
  /* When we already have some bits in our internal buffer concatenate
     both inputs first.  */
  if (ctx->buflen != 0) {
    size_t left_over = ctx->buflen;
    size_t add = 128 - left_over > len ? len : 128 - left_over;

    memcpy(&ctx->buffer[left_over], buffer, add);
    ctx->buflen += add;

    if (left_over + add > 64) {
      md5_process_block(ctx->buffer, (left_over + add) & ~63, ctx);
      /* The regions in the following copy operation cannot overlap.  */
      memcpy(ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
	     (left_over + add) & 63);
      ctx->buflen = (left_over + add) & 63;
    }

    buffer = (const char *) buffer + add;
    len -= add;
  }

  /* Process available complete blocks.  */
  if (len > 64) {
    md5_process_block(buffer, len & ~63, ctx);
    buffer = (const char *) buffer + (len & ~63);
    len &= 63;
  }

  /* Move remaining bytes in internal buffer.  */
  if (len > 0) {
    memcpy(ctx->buffer, buffer, len);
    ctx->buflen = len;
  }
}

/* These are the four functions used in the four steps of the MD5 algorithm
   and defined in the RFC 1321.  The first function is a little bit optimized
   (as found in Colin Plumbs public domain implementation).  */
/* #define FF(b, c, d) ((b & c) | (~b & d)) */
#define FF(b, c, d) (d ^ (b & (c ^ d)))
#define FG(b, c, d) FF (d, b, c)
#define FH(b, c, d) (b ^ c ^ d)
#define FI(b, c, d) (c ^ (b | ~d))

/* Process LEN bytes of BUFFER, accumulating context into CTX.
   It is assumed that LEN % 64 == 0.  */
void md5_process_block(const void *buffer, size_t len, struct md5_ctx *ctx)
{
  md5_uint32 correct_words[16];
  const md5_uint32 *words = buffer;
  size_t nwords = len / sizeof(md5_uint32);
  const md5_uint32 *endp = words + nwords;
  md5_uint32 A = ctx->A;
  md5_uint32 B = ctx->B;
  md5_uint32 C = ctx->C;
  md5_uint32 D = ctx->D;

  /* First increment the byte count.  RFC 1321 specifies the possible
     length of the file up to 2^64 bits.  Here we only compute the
     number of bytes.  Do a double word increment.  */
  ctx->total[0] += len;
  if (ctx->total[0] < len)
    ++ctx->total[1];

  /* Process all bytes in the buffer with 64 bytes in each round of
     the loop.  */
  while (words < endp) {
    md5_uint32 *cwp = correct_words;
    md5_uint32 A_save = A;
    md5_uint32 B_save = B;
    md5_uint32 C_save = C;
    md5_uint32 D_save = D;

    /* First round: using the given function, the context and a constant
       the next context is computed.  Because the algorithms processing
       unit is a 32-bit word and it is determined to work on words in
       little endian byte order we perhaps have to change the byte order
       before the computation.  To reduce the work for the next steps
       we store the swapped words in the array CORRECT_WORDS.  */

#define OP(a, b, c, d, s, T)						\
      do								\
        {								\
	  a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T;		\
	  ++words;							\
	  CYCLIC (a, s);						\
	  a += b;							\
        }								\
      while (0)

    /* It is unfortunate that C does not provide an operator for
       cyclic rotation.  Hope the C compiler is smart enough.  */
#define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s)))

    /* Before we start, one word to the strange constants.
       They are defined in RFC 1321 as

       T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64
    */

    /* Round 1.  */
    OP(A, B, C, D, 7, 0xd76aa478);
    OP(D, A, B, C, 12, 0xe8c7b756);
    OP(C, D, A, B, 17, 0x242070db);
    OP(B, C, D, A, 22, 0xc1bdceee);
    OP(A, B, C, D, 7, 0xf57c0faf);
    OP(D, A, B, C, 12, 0x4787c62a);
    OP(C, D, A, B, 17, 0xa8304613);
    OP(B, C, D, A, 22, 0xfd469501);
    OP(A, B, C, D, 7, 0x698098d8);
    OP(D, A, B, C, 12, 0x8b44f7af);
    OP(C, D, A, B, 17, 0xffff5bb1);
    OP(B, C, D, A, 22, 0x895cd7be);
    OP(A, B, C, D, 7, 0x6b901122);
    OP(D, A, B, C, 12, 0xfd987193);
    OP(C, D, A, B, 17, 0xa679438e);
    OP(B, C, D, A, 22, 0x49b40821);

    /* For the second to fourth round we have the possibly swapped words
       in CORRECT_WORDS.  Redefine the macro to take an additional first
       argument specifying the function to use.  */
#undef OP
#define OP(f, a, b, c, d, k, s, T)					\
      do 								\
	{								\
	  a += f (b, c, d) + correct_words[k] + T;			\
	  CYCLIC (a, s);						\
	  a += b;							\
	}								\
      while (0)

    /* Round 2.  */
    OP(FG, A, B, C, D, 1, 5, 0xf61e2562);
    OP(FG, D, A, B, C, 6, 9, 0xc040b340);
    OP(FG, C, D, A, B, 11, 14, 0x265e5a51);
    OP(FG, B, C, D, A, 0, 20, 0xe9b6c7aa);
    OP(FG, A, B, C, D, 5, 5, 0xd62f105d);
    OP(FG, D, A, B, C, 10, 9, 0x02441453);
    OP(FG, C, D, A, B, 15, 14, 0xd8a1e681);
    OP(FG, B, C, D, A, 4, 20, 0xe7d3fbc8);
    OP(FG, A, B, C, D, 9, 5, 0x21e1cde6);
    OP(FG, D, A, B, C, 14, 9, 0xc33707d6);
    OP(FG, C, D, A, B, 3, 14, 0xf4d50d87);
    OP(FG, B, C, D, A, 8, 20, 0x455a14ed);
    OP(FG, A, B, C, D, 13, 5, 0xa9e3e905);
    OP(FG, D, A, B, C, 2, 9, 0xfcefa3f8);
    OP(FG, C, D, A, B, 7, 14, 0x676f02d9);
    OP(FG, B, C, D, A, 12, 20, 0x8d2a4c8a);

    /* Round 3.  */
    OP(FH, A, B, C, D, 5, 4, 0xfffa3942);
    OP(FH, D, A, B, C, 8, 11, 0x8771f681);
    OP(FH, C, D, A, B, 11, 16, 0x6d9d6122);
    OP(FH, B, C, D, A, 14, 23, 0xfde5380c);
    OP(FH, A, B, C, D, 1, 4, 0xa4beea44);
    OP(FH, D, A, B, C, 4, 11, 0x4bdecfa9);
    OP(FH, C, D, A, B, 7, 16, 0xf6bb4b60);
    OP(FH, B, C, D, A, 10, 23, 0xbebfbc70);
    OP(FH, A, B, C, D, 13, 4, 0x289b7ec6);
    OP(FH, D, A, B, C, 0, 11, 0xeaa127fa);
    OP(FH, C, D, A, B, 3, 16, 0xd4ef3085);
    OP(FH, B, C, D, A, 6, 23, 0x04881d05);
    OP(FH, A, B, C, D, 9, 4, 0xd9d4d039);
    OP(FH, D, A, B, C, 12, 11, 0xe6db99e5);
    OP(FH, C, D, A, B, 15, 16, 0x1fa27cf8);
    OP(FH, B, C, D, A, 2, 23, 0xc4ac5665);

    /* Round 4.  */
    OP(FI, A, B, C, D, 0, 6, 0xf4292244);
    OP(FI, D, A, B, C, 7, 10, 0x432aff97);
    OP(FI, C, D, A, B, 14, 15, 0xab9423a7);
    OP(FI, B, C, D, A, 5, 21, 0xfc93a039);
    OP(FI, A, B, C, D, 12, 6, 0x655b59c3);
    OP(FI, D, A, B, C, 3, 10, 0x8f0ccc92);
    OP(FI, C, D, A, B, 10, 15, 0xffeff47d);
    OP(FI, B, C, D, A, 1, 21, 0x85845dd1);
    OP(FI, A, B, C, D, 8, 6, 0x6fa87e4f);
    OP(FI, D, A, B, C, 15, 10, 0xfe2ce6e0);
    OP(FI, C, D, A, B, 6, 15, 0xa3014314);
    OP(FI, B, C, D, A, 13, 21, 0x4e0811a1);
    OP(FI, A, B, C, D, 4, 6, 0xf7537e82);
    OP(FI, D, A, B, C, 11, 10, 0xbd3af235);
    OP(FI, C, D, A, B, 2, 15, 0x2ad7d2bb);
    OP(FI, B, C, D, A, 9, 21, 0xeb86d391);

    /* Add the starting values of the context.  */
    A += A_save;
    B += B_save;
    C += C_save;
    D += D_save;
  }

  /* Put checksum in context given as argument.  */
  ctx->A = A;
  ctx->B = B;
  ctx->C = C;
  ctx->D = D;
}

//----------------------------------------------------------------------------
//--------end of md5.c
//----------------------------------------------------------------------------

#define ISWHITE(c) ((c) == ' ' || (c) == '\t')
#define IN_CTYPE_DOMAIN(c) 1
#define ISXDIGIT(c) (IN_CTYPE_DOMAIN (c) && isxdigit (c))
#define STREQ(a, b) (strcmp ((a), (b)) == 0)
#define TOLOWER(Ch) tolower (Ch)
#define OPENOPTS(BINARY) "r"

/* The minimum length of a valid digest line in a file produced
   by `md5sum FILE' and read by `md5sum -c'.  This length does
   not include any newline character at the end of a line.  */
static const int MIN_DIGEST_LINE_LENGTH = 35; /* 32 - message digest length
                                      2 - blank and binary indicator
                                      1 - minimum filename length */

static int have_read_stdin; /* Nonzero if any of the files read were
                               the standard input. */

static int status_only = 0; /* With -c, don't generate any output.
                               The exit code indicates success or failure */
static int warn = 0; /* With -w, print a message to standard error warning
                        about each improperly formatted MD5 checksum line */

static int split_3(char *s,
                   size_t s_len,
                   unsigned char **u,
                   int *binary,
                   char **w)
{
  size_t i = 0;
  int escaped_filename = 0;

  while (ISWHITE(s[i]))
    ++i;

  /* The line must have at least 35 (36 if the first is a backslash)
     more characters to contain correct message digest information.
     Ignore this line if it is too short.  */
  if (!(s_len - i >= MIN_DIGEST_LINE_LENGTH
        || (s[i] == '\\' && s_len - i >= 1 + MIN_DIGEST_LINE_LENGTH)))
    return FALSE;

  if (s[i] == '\\') {
    ++i;
    escaped_filename = 1;
  }
  *u = (unsigned char *) &s[i];

  /* The first field has to be the 32-character hexadecimal
     representation of the message digest.  If it is not followed
     immediately by a white space it's an error.  */
  i += 32;
  if (!ISWHITE(s[i]))
    return FALSE;

  s[i++] = '\0';

  if (s[i] != ' ' && s[i] != '*')
    return FALSE;
  *binary = (s[i++] == '*');

  /* All characters between the type indicator and end of line are
     significant -- that includes leading and trailing white space.  */
  *w = &s[i];

  if (escaped_filename) {
    /* Translate each `\n' string in the file name to a NEWLINE,
       and each `\\' string to a backslash.  */

    char *dst = &s[i];

    while (i < s_len) {
      switch (s[i]) {
       case '\\':
        if (i == s_len - 1) {
          /* A valid line does not end with a backslash.  */
          return FALSE;
        }
        ++i;
        switch (s[i++]) {
         case 'n':
          *dst++ = '\n';
          break;
         case '\\':
          *dst++ = '\\';
          break;
         default:
          /* Only `\' or `n' may follow a backslash.  */
          return FALSE;
        }
        break;

       case '\0':
        /* The file name may not contain a NUL.  */
        return FALSE;
        break;

       default:
        *dst++ = s[i++];
        break;
      }
    }
    *dst = '\0';
  }
  return TRUE;
}

static int hex_digits(unsigned char const *s)
{
  while (*s) {
    if (!ISXDIGIT(*s))
      return TRUE;
    ++s;
  }
  return FALSE;
}

/* An interface to md5_stream.  Operate on FILENAME (it may be "-") and
   put the result in *MD5_RESULT.  Return non-zero upon failure, zero
   to indicate success.  */
static int md5_file(const char *filename,
                    int binary,
                    unsigned char *md5_result)
{
  FILE *fp;

  if (STREQ(filename, "-")) {
    have_read_stdin = 1;
    fp = stdin;
  } else {
    fp = fopen(filename, OPENOPTS(binary));
    if (fp == NULL) {
      perror_msg("%s", filename);
      return FALSE;
    }
  }

  if (md5_stream(fp, md5_result)) {
    perror_msg("%s", filename);

    if (fp != stdin)
      fclose(fp);
    return FALSE;
  }

  if (fp != stdin && fclose(fp) == EOF) {
    perror_msg("%s", filename);
    return FALSE;
  }

  return TRUE;
}

static int md5_check(const char *checkfile_name)
{
  FILE *checkfile_stream;
  int n_properly_formated_lines = 0;
  int n_mismatched_checksums = 0;
  int n_open_or_read_failures = 0;
  unsigned char md5buffer[16];
  size_t line_number;
  char line[BUFSIZ];

  if (STREQ(checkfile_name, "-")) {
    have_read_stdin = 1;
    checkfile_stream = stdin;
  } else {
    checkfile_stream = fopen(checkfile_name, "r");
    if (checkfile_stream == NULL) {
      perror_msg("%s", checkfile_name);
      return FALSE;
    }
  }

  line_number = 0;

  do {
    char *filename;
    int binary;
    unsigned char *md5num;
    int line_length;

    ++line_number;

    fgets(line, BUFSIZ-1, checkfile_stream);
    line_length = strlen(line);

    if (line_length <= 0 || line==NULL)
      break;

    /* Ignore comment lines, which begin with a '#' character.  */
    if (line[0] == '#')
      continue;

    /* Remove any trailing newline.  */
    if (line[line_length - 1] == '\n')
      line[--line_length] = '\0';

    if (split_3(line, line_length, &md5num, &binary, &filename)
        || !hex_digits(md5num)) {
      if (warn) {
        error_msg("%s: %lu: improperly formatted MD5 checksum line",
                 checkfile_name, (unsigned long) line_number);
      }
    } else {
      static const char bin2hex[] = {
        '0', '1', '2', '3',
        '4', '5', '6', '7',
        '8', '9', 'a', 'b',
        'c', 'd', 'e', 'f'
      };

      ++n_properly_formated_lines;

      if (md5_file(filename, binary, md5buffer)) {
        ++n_open_or_read_failures;
        if (!status_only) {
          printf("%s: FAILED open or read\n", filename);
          fflush(stdout);
        }
      } else {
        size_t cnt;
        /* Compare generated binary number with text representation
           in check file.  Ignore case of hex digits.  */
        for (cnt = 0; cnt < 16; ++cnt) {
          if (TOLOWER(md5num[2 * cnt])
              != bin2hex[md5buffer[cnt] >> 4]
              || (TOLOWER(md5num[2 * cnt + 1])
                  != (bin2hex[md5buffer[cnt] & 0xf])))
            break;
        }
        if (cnt != 16)
          ++n_mismatched_checksums;

        if (!status_only) {
          printf("%s: %s\n", filename,
                 (cnt != 16 ? "FAILED" : "OK"));
          fflush(stdout);
        }
      }
    }
  }

  while (!feof(checkfile_stream) && !ferror(checkfile_stream));

  if (ferror(checkfile_stream)) {
    error_msg("%s: read error", checkfile_name);
    return FALSE;
  }

  if (checkfile_stream != stdin && fclose(checkfile_stream) == EOF) {
    perror_msg("md5sum: %s", checkfile_name);
    return FALSE;
  }

  if (n_properly_formated_lines == 0) {
    /* Warn if no tests are found.  */
    error_msg("%s: no properly formatted MD5 checksum lines found",
             checkfile_name);
    return FALSE;
  } else {
    if (!status_only) {
      int n_computed_checkums = (n_properly_formated_lines
                                 - n_open_or_read_failures);

      if (n_open_or_read_failures > 0) {
        error_msg("WARNING: %d of %d listed files could not be read",
                 n_open_or_read_failures, n_properly_formated_lines);
        return FALSE;
      }

      if (n_mismatched_checksums > 0) {
        error_msg("WARNING: %d of %d computed checksums did NOT match",
                 n_mismatched_checksums, n_computed_checkums);
        return FALSE;
      }
    }
  }

  return ((n_properly_formated_lines > 0 && n_mismatched_checksums == 0
           && n_open_or_read_failures == 0) ? 0 : 1);
}

int md5sum_main(int argc,
                char **argv)
{
  unsigned char md5buffer[16];
  int do_check = 0;
  int opt;
  char **string = NULL;
  size_t n_strings = 0;
  size_t err = 0;
  int file_type_specified = 0;
  int binary = 0;

  while ((opt = getopt(argc, argv, "g:bcstw")) != -1) {
    switch (opt) {
     case 'g': { /* read a string */
       if (string == NULL)
         string = (char **) xmalloc ((argc - 1) * sizeof (char *));

       string[n_strings++] = optarg;
       break;
     }

     case 'b': /* read files in binary mode */
      file_type_specified = 1;
      binary = 1;
      break;

     case 'c': /* check MD5 sums against given list */
      do_check = 1;
      break;

     case 's':  /* don't output anything, status code shows success */
      status_only = 1;
      warn = 0;
      break;

     case 't': /* read files in text mode (default) */
      file_type_specified = 1;
      binary = 0;
      break;

     case 'w': /* warn about improperly formated MD5 checksum lines */
      status_only = 0;
      warn = 1;
      break;

     default:
      show_usage();
    }
  }

  if (file_type_specified && do_check) {
    error_msg_and_die("the -b and -t options are meaningless when verifying checksums");
  }

  if (n_strings > 0 && do_check) {
    error_msg_and_die("the -g and -c options are mutually exclusive");
  }

  if (status_only && !do_check) {
    error_msg_and_die("the -s option is meaningful only when verifying checksums");
  }

  if (warn && !do_check) {
    error_msg_and_die("the -w option is meaningful only when verifying checksums");
  }

  if (n_strings > 0) {
    size_t i;

    if (optind < argc) {
      error_msg_and_die("no files may be specified when using -g");
    }
    for (i = 0; i < n_strings; ++i) {
      size_t cnt;
      md5_buffer (string[i], strlen (string[i]), md5buffer);

      for (cnt = 0; cnt < 16; ++cnt)
        printf ("%02x", md5buffer[cnt]);

      printf ("  \"%s\"\n", string[i]);
    }
  } else if (do_check) {
    if (optind + 1 < argc) {
      error_msg("only one argument may be specified when using -c");
    }

    err = md5_check ((optind == argc) ? "-" : argv[optind]);
  } else {
    if (optind == argc)
      argv[argc++] = "-";

    for (; optind < argc; ++optind) {
      int fail;
      char *file = argv[optind];

      fail = md5_file (file, binary, md5buffer);
      err |= fail;
      if (!fail && STREQ(file, "-")) {
	  size_t i;
	  for (i = 0; i < 16; ++i)
	      printf ("%02x", md5buffer[i]);
	  putchar ('\n');
      } else if (!fail) {
        size_t i;
        /* Output a leading backslash if the file name contains
           a newline or backslash.  */
        if (strchr (file, '\n') || strchr (file, '\\'))
          putchar ('\\');

        for (i = 0; i < 16; ++i)
          printf ("%02x", md5buffer[i]);

        putchar (' ');
        if (binary)
          putchar ('*');
        else
          putchar (' ');

        /* Translate each NEWLINE byte to the string, "\\n",
           and each backslash to "\\\\".  */
        for (i = 0; i < strlen (file); ++i) {
          switch (file[i]) {
           case '\n':
            fputs ("\\n", stdout);
            break;

           case '\\':
            fputs ("\\\\", stdout);
            break;

           default:
            putchar (file[i]);
            break;
          }
        }
        putchar ('\n');
      }
    }
  }

  if (fclose (stdout) == EOF) {
    error_msg_and_die("write error");
  }

  if (have_read_stdin && fclose (stdin) == EOF) {
    error_msg_and_die("standard input");
  }

  if (err == 0)
	  return EXIT_SUCCESS;
  else
	  return EXIT_FAILURE;
}