src/digest.c

   1 /* Compute checksums of files or strings.
   2    Copyright (C) 1995-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>.  */
  18
  19 #include <config.h>
  20
  21 #include <getopt.h>
  22 #include <sys/types.h>
  23
  24 #include "system.h"
  25 #include "argmatch.h"
  26 #include "c-ctype.h"
  27 #include "quote.h"
  28 #include "xdectoint.h"
  29 #include "xstrtol.h"
  30
  31 #ifndef HASH_ALGO_CKSUM
  32 # define HASH_ALGO_CKSUM 0
  33 #endif
  34
  35 #if HASH_ALGO_SUM || HASH_ALGO_CKSUM
  36 # include "sum.h"
  37 #endif
  38 #if HASH_ALGO_CKSUM
  39 # include "cksum.h"
  40 # include "base64.h"
  41 #endif
  42 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
  43 # include "blake2/b2sum.h"
  44 #endif
  45 #if HASH_ALGO_MD5 || HASH_ALGO_CKSUM
  46 # include "md5.h"
  47 #endif
  48 #if HASH_ALGO_SHA1 || HASH_ALGO_CKSUM
  49 # include "sha1.h"
  50 #endif
  51 #if HASH_ALGO_SHA256 || HASH_ALGO_SHA224 || HASH_ALGO_CKSUM
  52 # include "sha256.h"
  53 #endif
  54 #if HASH_ALGO_SHA512 || HASH_ALGO_SHA384 || HASH_ALGO_CKSUM
  55 # include "sha512.h"
  56 #endif
  57 #if HASH_ALGO_CKSUM
  58 # include "sm3.h"
  59 #endif
  60 #include "fadvise.h"
  61 #include "stdio--.h"
  62 #include "xbinary-io.h"
  63
  64 /* The official name of this program (e.g., no 'g' prefix).  */
  65 #if HASH_ALGO_SUM
  66 # define PROGRAM_NAME "sum"
  67 # define DIGEST_TYPE_STRING "BSD"
  68 # define DIGEST_STREAM sumfns[sum_algorithm]
  69 # define DIGEST_OUT sum_output_fns[sum_algorithm]
  70 # define DIGEST_BITS 16
  71 # define DIGEST_ALIGN 4
  72 #elif HASH_ALGO_CKSUM
  73 # define MAX_DIGEST_BITS 512
  74 # define MAX_DIGEST_ALIGN 8
  75 # define PROGRAM_NAME "cksum"
  76 # define DIGEST_TYPE_STRING algorithm_tags[cksum_algorithm]
  77 # define DIGEST_STREAM cksumfns[cksum_algorithm]
  78 # define DIGEST_OUT cksum_output_fns[cksum_algorithm]
  79 # define DIGEST_BITS MAX_DIGEST_BITS
  80 # define DIGEST_ALIGN MAX_DIGEST_ALIGN
  81 #elif HASH_ALGO_MD5
  82 # define PROGRAM_NAME "md5sum"
  83 # define DIGEST_TYPE_STRING "MD5"
  84 # define DIGEST_STREAM md5_stream
  85 # define DIGEST_BITS 128
  86 # define DIGEST_REFERENCE "RFC 1321"
  87 # define DIGEST_ALIGN 4
  88 #elif HASH_ALGO_BLAKE2
  89 # define PROGRAM_NAME "b2sum"
  90 # define DIGEST_TYPE_STRING "BLAKE2b"
  91 # define DIGEST_STREAM blake2b_stream
  92 # define DIGEST_BITS 512
  93 # define DIGEST_REFERENCE "RFC 7693"
  94 # define DIGEST_ALIGN 8
  95 #elif HASH_ALGO_SHA1
  96 # define PROGRAM_NAME "sha1sum"
  97 # define DIGEST_TYPE_STRING "SHA1"
  98 # define DIGEST_STREAM sha1_stream
  99 # define DIGEST_BITS 160
 100 # define DIGEST_REFERENCE "FIPS-180-1"
 101 # define DIGEST_ALIGN 4
 102 #elif HASH_ALGO_SHA256
 103 # define PROGRAM_NAME "sha256sum"
 104 # define DIGEST_TYPE_STRING "SHA256"
 105 # define DIGEST_STREAM sha256_stream
 106 # define DIGEST_BITS 256
 107 # define DIGEST_REFERENCE "FIPS-180-2"
 108 # define DIGEST_ALIGN 4
 109 #elif HASH_ALGO_SHA224
 110 # define PROGRAM_NAME "sha224sum"
 111 # define DIGEST_TYPE_STRING "SHA224"
 112 # define DIGEST_STREAM sha224_stream
 113 # define DIGEST_BITS 224
 114 # define DIGEST_REFERENCE "RFC 3874"
 115 # define DIGEST_ALIGN 4
 116 #elif HASH_ALGO_SHA512
 117 # define PROGRAM_NAME "sha512sum"
 118 # define DIGEST_TYPE_STRING "SHA512"
 119 # define DIGEST_STREAM sha512_stream
 120 # define DIGEST_BITS 512
 121 # define DIGEST_REFERENCE "FIPS-180-2"
 122 # define DIGEST_ALIGN 8
 123 #elif HASH_ALGO_SHA384
 124 # define PROGRAM_NAME "sha384sum"
 125 # define DIGEST_TYPE_STRING "SHA384"
 126 # define DIGEST_STREAM sha384_stream
 127 # define DIGEST_BITS 384
 128 # define DIGEST_REFERENCE "FIPS-180-2"
 129 # define DIGEST_ALIGN 8
 130 #else
 131 # error "Can't decide which hash algorithm to compile."
 132 #endif
 133 #if !HASH_ALGO_SUM && !HASH_ALGO_CKSUM
 134 # define DIGEST_OUT output_file
 135 #endif
 136
 137 #if HASH_ALGO_SUM
 138 # define AUTHORS \
 139   proper_name ("Kayvan Aghaiepour"), \
 140   proper_name ("David MacKenzie")
 141 #elif HASH_ALGO_CKSUM
 142 # define AUTHORS \
 143   proper_name_lite ("Padraig Brady", "P\303\241draig Brady"), \
 144   proper_name ("Q. Frank Xia")
 145 #elif HASH_ALGO_BLAKE2
 146 # define AUTHORS \
 147   proper_name_lite ("Padraig Brady", "P\303\241draig Brady"), \
 148   proper_name ("Samuel Neves")
 149 #else
 150 # define AUTHORS \
 151   proper_name ("Ulrich Drepper"), \
 152   proper_name ("Scott Miller"), \
 153   proper_name ("David Madore")
 154 #endif
 155 #if !HASH_ALGO_BLAKE2 && !HASH_ALGO_CKSUM
 156 # define DIGEST_HEX_BYTES (DIGEST_BITS / 4)
 157 #endif
 158 #define DIGEST_BIN_BYTES (DIGEST_BITS / 8)
 159
 160 /* The minimum length of a valid digest line.  This length does
 161    not include any newline character at the end of a line.  */
 162 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 163 # define MIN_DIGEST_LINE_LENGTH 3 /* With -l 8.  */
 164 #else
 165 # define MIN_DIGEST_LINE_LENGTH \
 166    (DIGEST_HEX_BYTES /* length of hexadecimal message digest */ \
 167     + 1 /* blank */ \
 168     + 1 /* minimum filename length */ )
 169 #endif
 170
 171 #if !HASH_ALGO_SUM
 172 static void
 173 output_file (char const *file, int binary_file, void const *digest,
 174              bool raw, bool tagged, unsigned char delim, bool args,
 175              uintmax_t length);
 176 #endif
 177
 178 /* True if any of the files read were the standard input. */
 179 static bool have_read_stdin;
 180
 181 /* The minimum length of a valid checksum line for the selected algorithm.  */
 182 static size_t min_digest_line_length;
 183
 184 /* Set to the length of a digest hex string for the selected algorithm.  */
 185 static size_t digest_hex_bytes;
 186
 187 /* With --check, don't generate any output.
 188    The exit code indicates success or failure.  */
 189 static bool status_only = false;
 190
 191 /* With --check, print a message to standard error warning about each
 192    improperly formatted checksum line.  */
 193 static bool warn = false;
 194
 195 /* With --check, ignore missing files.  */
 196 static bool ignore_missing = false;
 197
 198 /* With --check, suppress the "OK" printed for each verified file.  */
 199 static bool quiet = false;
 200
 201 /* With --check, exit with a non-zero return code if any line is
 202    improperly formatted. */
 203 static bool strict = false;
 204
 205 /* Whether a BSD reversed format checksum is detected.  */
 206 static int bsd_reversed = -1;
 207
 208 /* line delimiter.  */
 209 static unsigned char digest_delim = '\n';
 210
 211 #if HASH_ALGO_CKSUM
 212 /* If true, print base64-encoded digests, not hex.  */
 213 static bool base64_digest = false;
 214 #endif
 215
 216 /* If true, print binary digests, not hex.  */
 217 static bool raw_digest = false;
 218
 219 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 220 # define BLAKE2B_MAX_LEN BLAKE2B_OUTBYTES
 221 static uintmax_t digest_length;
 222 #endif /* HASH_ALGO_BLAKE2 */
 223
 224 typedef void (*digest_output_fn)(char const *, int, void const *, bool,
 225                                  bool, unsigned char, bool, uintmax_t);
 226 #if HASH_ALGO_SUM
 227 enum Algorithm
 228 {
 229   bsd,
 230   sysv,
 231 };
 232
 233 static enum Algorithm sum_algorithm;
 234 static sumfn sumfns[]=
 235 {
 236   bsd_sum_stream,
 237   sysv_sum_stream,
 238 };
 239 static digest_output_fn sum_output_fns[]=
 240 {
 241   output_bsd,
 242   output_sysv,
 243 };
 244 #endif
 245
 246 #if HASH_ALGO_CKSUM
 247 static int
 248 md5_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 249 {
 250   return md5_stream (stream, resstream);
 251 }
 252 static int
 253 sha1_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 254 {
 255   return sha1_stream (stream, resstream);
 256 }
 257 static int
 258 sha224_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 259 {
 260   return sha224_stream (stream, resstream);
 261 }
 262 static int
 263 sha256_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 264 {
 265   return sha256_stream (stream, resstream);
 266 }
 267 static int
 268 sha384_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 269 {
 270   return sha384_stream (stream, resstream);
 271 }
 272 static int
 273 sha512_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 274 {
 275   return sha512_stream (stream, resstream);
 276 }
 277 static int
 278 blake2b_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 279 {
 280   return blake2b_stream (stream, resstream, *length);
 281 }
 282 static int
 283 sm3_sum_stream (FILE *stream, void *resstream, uintmax_t *length)
 284 {
 285   return sm3_stream (stream, resstream);
 286 }
 287
 288 enum Algorithm
 289 {
 290   bsd,
 291   sysv,
 292   crc,
 293   md5,
 294   sha1,
 295   sha224,
 296   sha256,
 297   sha384,
 298   sha512,
 299   blake2b,
 300   sm3,
 301 };
 302
 303 static char const *const algorithm_args[] =
 304 {
 305   "bsd", "sysv", "crc", "md5", "sha1", "sha224",
 306   "sha256", "sha384", "sha512", "blake2b", "sm3", nullptr
 307 };
 308 static enum Algorithm const algorithm_types[] =
 309 {
 310   bsd, sysv, crc, md5, sha1, sha224,
 311   sha256, sha384, sha512, blake2b, sm3,
 312 };
 313 ARGMATCH_VERIFY (algorithm_args, algorithm_types);
 314
 315 static char const *const algorithm_tags[] =
 316 {
 317   "BSD", "SYSV", "CRC", "MD5", "SHA1", "SHA224",
 318   "SHA256", "SHA384", "SHA512", "BLAKE2b", "SM3", nullptr
 319 };
 320 static int const algorithm_bits[] =
 321 {
 322   16, 16, 32, 128, 160, 224,
 323   256, 384, 512, 512, 256, 0
 324 };
 325
 326 static_assert (ARRAY_CARDINALITY (algorithm_bits)
 327                == ARRAY_CARDINALITY (algorithm_args));
 328
 329 static bool algorithm_specified = false;
 330 static enum Algorithm cksum_algorithm = crc;
 331 static sumfn cksumfns[]=
 332 {
 333   bsd_sum_stream,
 334   sysv_sum_stream,
 335   crc_sum_stream,
 336   md5_sum_stream,
 337   sha1_sum_stream,
 338   sha224_sum_stream,
 339   sha256_sum_stream,
 340   sha384_sum_stream,
 341   sha512_sum_stream,
 342   blake2b_sum_stream,
 343   sm3_sum_stream,
 344 };
 345 static digest_output_fn cksum_output_fns[]=
 346 {
 347   output_bsd,
 348   output_sysv,
 349   output_crc,
 350   output_file,
 351   output_file,
 352   output_file,
 353   output_file,
 354   output_file,
 355   output_file,
 356   output_file,
 357   output_file,
 358 };
 359 bool cksum_debug;
 360 #endif
 361
 362 /* For long options that have no equivalent short option, use a
 363    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
 364
 365 enum
 366 {
 367   IGNORE_MISSING_OPTION = CHAR_MAX + 1,
 368   STATUS_OPTION,
 369   QUIET_OPTION,
 370   STRICT_OPTION,
 371   TAG_OPTION,
 372   UNTAG_OPTION,
 373   DEBUG_PROGRAM_OPTION,
 374   RAW_OPTION,
 375   BASE64_OPTION,
 376 };
 377
 378 static struct option const long_options[] =
 379 {
 380 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 381   { "length", required_argument, nullptr, 'l'},
 382 #endif
 383
 384 #if !HASH_ALGO_SUM
 385   { "check", no_argument, nullptr, 'c' },
 386   { "ignore-missing", no_argument, nullptr, IGNORE_MISSING_OPTION},
 387   { "quiet", no_argument, nullptr, QUIET_OPTION },
 388   { "status", no_argument, nullptr, STATUS_OPTION },
 389   { "warn", no_argument, nullptr, 'w' },
 390   { "strict", no_argument, nullptr, STRICT_OPTION },
 391   { "tag", no_argument, nullptr, TAG_OPTION },
 392   { "zero", no_argument, nullptr, 'z' },
 393
 394 # if HASH_ALGO_CKSUM
 395   { "algorithm", required_argument, nullptr, 'a'},
 396   { "base64", no_argument, nullptr, BASE64_OPTION },
 397   { "debug", no_argument, nullptr, DEBUG_PROGRAM_OPTION},
 398   { "raw", no_argument, nullptr, RAW_OPTION},
 399   { "untagged", no_argument, nullptr, UNTAG_OPTION },
 400 # endif
 401   { "binary", no_argument, nullptr, 'b' },
 402   { "text", no_argument, nullptr, 't' },
 403
 404 #else
 405   {"sysv", no_argument, nullptr, 's'},
 406 #endif
 407
 408   { GETOPT_HELP_OPTION_DECL },
 409   { GETOPT_VERSION_OPTION_DECL },
 410   { nullptr, 0, nullptr, 0 }
 411 };
 412
 413 void
 414 usage (int status)
 415 {
 416   if (status != EXIT_SUCCESS)
 417     emit_try_help ();
 418   else
 419     {
 420       printf (_("\
 421 Usage: %s [OPTION]... [FILE]...\n\
 422 "), program_name);
 423 #if HASH_ALGO_CKSUM
 424       fputs (_("\
 425 Print or verify checksums.\n\
 426 By default use the 32 bit CRC algorithm.\n\
 427 "), stdout);
 428 #else
 429       printf (_("\
 430 Print or check %s (%d-bit) checksums.\n\
 431 "),
 432               DIGEST_TYPE_STRING,
 433               DIGEST_BITS);
 434 #endif
 435
 436       emit_stdin_note ();
 437 #if HASH_ALGO_SUM
 438       fputs (_("\
 439 \n\
 440   -r              use BSD sum algorithm (the default), use 1K blocks\n\
 441   -s, --sysv      use System V sum algorithm, use 512 bytes blocks\n\
 442 "), stdout);
 443 #endif
 444 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 445         emit_mandatory_arg_note ();
 446 #endif
 447 #if HASH_ALGO_CKSUM
 448         fputs (_("\
 449   -a, --algorithm=TYPE  select the digest type to use.  See DIGEST below.\
 450 \n\
 451 "), stdout);
 452         fputs (_("\
 453       --base64          emit base64-encoded digests, not hexadecimal\
 454 \n\
 455 "), stdout);
 456 #endif
 457 #if !HASH_ALGO_SUM
 458 # if !HASH_ALGO_CKSUM
 459       if (O_BINARY)
 460         fputs (_("\
 461   -b, --binary          read in binary mode (default unless reading tty stdin)\
 462 \n\
 463 "), stdout);
 464       else
 465         fputs (_("\
 466   -b, --binary          read in binary mode\n\
 467 "), stdout);
 468 # endif
 469         fputs (_("\
 470   -c, --check           read checksums from the FILEs and check them\n\
 471 "), stdout);
 472 # if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 473         fputs (_("\
 474   -l, --length=BITS     digest length in bits; must not exceed the max for\n\
 475                           the blake2 algorithm and must be a multiple of 8\n\
 476 "), stdout);
 477 # endif
 478 # if HASH_ALGO_CKSUM
 479         fputs (_("\
 480       --raw             emit a raw binary digest, not hexadecimal\
 481 \n\
 482 "), stdout);
 483       fputs (_("\
 484       --tag             create a BSD-style checksum (the default)\n\
 485 "), stdout);
 486       fputs (_("\
 487       --untagged        create a reversed style checksum, without digest type\n\
 488 "), stdout);
 489 # else
 490       fputs (_("\
 491       --tag             create a BSD-style checksum\n\
 492 "), stdout);
 493 # endif
 494 # if !HASH_ALGO_CKSUM
 495       if (O_BINARY)
 496         fputs (_("\
 497   -t, --text            read in text mode (default if reading tty stdin)\n\
 498 "), stdout);
 499       else
 500         fputs (_("\
 501   -t, --text            read in text mode (default)\n\
 502 "), stdout);
 503 # endif
 504       fputs (_("\
 505   -z, --zero            end each output line with NUL, not newline,\n\
 506                           and disable file name escaping\n\
 507 "), stdout);
 508       fputs (_("\
 509 \n\
 510 The following five options are useful only when verifying checksums:\n\
 511       --ignore-missing  don't fail or report status for missing files\n\
 512       --quiet           don't print OK for each successfully verified file\n\
 513       --status          don't output anything, status code shows success\n\
 514       --strict          exit non-zero for improperly formatted checksum lines\n\
 515   -w, --warn            warn about improperly formatted checksum lines\n\
 516 \n\
 517 "), stdout);
 518 #endif
 519 #if HASH_ALGO_CKSUM
 520       fputs (_("\
 521       --debug           indicate which implementation used\n\
 522 "), stdout);
 523 #endif
 524       fputs (HELP_OPTION_DESCRIPTION, stdout);
 525       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 526 #if HASH_ALGO_CKSUM
 527       fputs (_("\
 528 \n\
 529 DIGEST determines the digest algorithm and default output format:\n\
 530   sysv      (equivalent to sum -s)\n\
 531   bsd       (equivalent to sum -r)\n\
 532   crc       (equivalent to cksum)\n\
 533   md5       (equivalent to md5sum)\n\
 534   sha1      (equivalent to sha1sum)\n\
 535   sha224    (equivalent to sha224sum)\n\
 536   sha256    (equivalent to sha256sum)\n\
 537   sha384    (equivalent to sha384sum)\n\
 538   sha512    (equivalent to sha512sum)\n\
 539   blake2b   (equivalent to b2sum)\n\
 540   sm3       (only available through cksum)\n\
 541 \n"), stdout);
 542 #endif
 543 #if !HASH_ALGO_SUM && !HASH_ALGO_CKSUM
 544       printf (_("\
 545 \n\
 546 The sums are computed as described in %s.\n"), DIGEST_REFERENCE);
 547       fputs (_("\
 548 When checking, the input should be a former output of this program.\n\
 549 The default mode is to print a line with: checksum, a space,\n\
 550 a character indicating input mode ('*' for binary, ' ' for text\n\
 551 or where binary is insignificant), and name for each FILE.\n\
 552 \n\
 553 There is no difference between binary mode and text mode on GNU systems.\
 554 \n"), stdout);
 555 #endif
 556 #if HASH_ALGO_CKSUM
 557       fputs (_("\
 558 When checking, the input should be a former output of this program,\n\
 559 or equivalent standalone program.\
 560 \n"), stdout);
 561 #endif
 562       emit_ancillary_info (PROGRAM_NAME);
 563     }
 564
 565   exit (status);
 566 }
 567
 568 /* Given a string S, return TRUE if it contains problematic characters
 569    that need escaping.  Note we escape '\' itself to provide some forward
 570    compat to introduce escaping of other characters.  */
 571
 572 ATTRIBUTE_PURE
 573 static bool
 574 problematic_chars (char const *s)
 575 {
 576   size_t length = strcspn (s, "\\\n\r");
 577   return s[length] != '\0';
 578 }
 579
 580 #define ISWHITE(c) ((c) == ' ' || (c) == '\t')
 581
 582 /* Given a file name, S of length S_LEN, that is not NUL-terminated,
 583    modify it in place, performing the equivalent of this sed substitution:
 584    's/\\n/\n/g;s/\\r/\r/g;s/\\\\/\\/g' i.e., replacing each "\\n" string
 585    with a newline, each "\\r" string with a carriage return,
 586    and each "\\\\" with a single backslash, NUL-terminate it and return S.
 587    If S is not a valid escaped file name, i.e., if it ends with an odd number
 588    of backslashes or if it contains a backslash followed by anything other
 589    than "n" or another backslash, return nullptr.  */
 590
 591 static char *
 592 filename_unescape (char *s, size_t s_len)
 593 {
 594   char *dst = s;
 595
 596   for (size_t i = 0; i < s_len; i++)
 597     {
 598       switch (s[i])
 599         {
 600         case '\\':
 601           if (i == s_len - 1)
 602             {
 603               /* File name ends with an unescaped backslash: invalid.  */
 604               return nullptr;
 605             }
 606           ++i;
 607           switch (s[i])
 608             {
 609             case 'n':
 610               *dst++ = '\n';
 611               break;
 612             case 'r':
 613               *dst++ = '\r';
 614               break;
 615             case '\\':
 616               *dst++ = '\\';
 617               break;
 618             default:
 619               /* Only '\', 'n' or 'r' may follow a backslash.  */
 620               return nullptr;
 621             }
 622           break;
 623
 624         case '\0':
 625           /* The file name may not contain a NUL.  */
 626           return nullptr;
 627
 628         default:
 629           *dst++ = s[i];
 630           break;
 631         }
 632     }
 633   if (dst < s + s_len)
 634     *dst = '\0';
 635
 636   return s;
 637 }
 638
 639 /* Return true if S is a LEN-byte NUL-terminated string of hex or base64
 640    digits and has the expected length.  Otherwise, return false.  */
 641 ATTRIBUTE_PURE
 642 static bool
 643 valid_digits (unsigned char const *s, size_t len)
 644 {
 645 #if HASH_ALGO_CKSUM
 646   if (len == BASE64_LENGTH (digest_length / 8))
 647     {
 648       size_t i;
 649       for (i = 0; i < len - digest_length % 3; i++)
 650         {
 651           if (!isbase64 (*s))
 652             return false;
 653           ++s;
 654         }
 655       for ( ; i < len; i++)
 656         {
 657           if (*s != '=')
 658             return false;
 659           ++s;
 660         }
 661     }
 662   else
 663 #endif
 664   if (len == digest_hex_bytes)
 665     {
 666       for (idx_t i = 0; i < digest_hex_bytes; i++)
 667         {
 668           if (!c_isxdigit (*s))
 669             return false;
 670           ++s;
 671         }
 672     }
 673   else
 674     return false;
 675
 676   return *s == '\0';
 677 }
 678
 679 /* Split the checksum string S (of length S_LEN) from a BSD 'md5' or
 680    'sha1' command into two parts: a hexadecimal digest, and the file
 681    name.  S is modified.  Set *D_LEN to the length of the digest string.
 682    Return true if successful.  */
 683
 684 static bool
 685 bsd_split_3 (char *s, size_t s_len,
 686              unsigned char **digest, size_t *d_len,
 687              char **file_name, bool escaped_filename)
 688 {
 689   if (s_len == 0)
 690     return false;
 691
 692   /* Find end of filename.  */
 693   size_t i = s_len - 1;
 694   while (i && s[i] != ')')
 695     i--;
 696
 697   if (s[i] != ')')
 698     return false;
 699
 700   *file_name = s;
 701
 702   if (escaped_filename && filename_unescape (s, i) == nullptr)
 703     return false;
 704
 705   s[i++] = '\0';
 706
 707   while (ISWHITE (s[i]))
 708     i++;
 709
 710   if (s[i] != '=')
 711     return false;
 712
 713   i++;
 714
 715   while (ISWHITE (s[i]))
 716     i++;
 717
 718   *digest = (unsigned char *) &s[i];
 719
 720   *d_len = s_len - i;
 721   return valid_digits (*digest, *d_len);
 722 }
 723
 724 #if HASH_ALGO_CKSUM
 725 /* Return the corresponding Algorithm for the string S,
 726    or -1 for no match.  */
 727
 728 static ptrdiff_t
 729 algorithm_from_tag (char *s)
 730 {
 731   /* Limit check size to this length for perf reasons.  */
 732   static size_t max_tag_len;
 733   if (! max_tag_len)
 734     {
 735       char const * const * tag = algorithm_tags;
 736       while (*tag)
 737         {
 738           size_t tag_len = strlen (*tag++);
 739           max_tag_len = MAX (tag_len, max_tag_len);
 740         }
 741     }
 742
 743   size_t i = 0;
 744
 745   /* Find end of tag */
 746   while (i <= max_tag_len && s[i] && ! ISWHITE (s[i])
 747          && s[i] != '-' && s[i] != '(')
 748     ++i;
 749
 750   if (i > max_tag_len)
 751     return -1;
 752
 753   /* Terminate tag, and lookup.  */
 754   char sep = s[i];
 755   s[i] = '\0';
 756   ptrdiff_t algo = argmatch_exact (s, algorithm_tags);
 757   s[i] = sep;
 758
 759   return algo;
 760 }
 761 #endif
 762
 763 /* Split the string S (of length S_LEN) into three parts:
 764    a hexadecimal digest, binary flag, and the file name.
 765    S is modified.  Set *D_LEN to the length of the digest string.
 766    Return true if successful.  */
 767
 768 static bool
 769 split_3 (char *s, size_t s_len,
 770          unsigned char **digest, size_t *d_len, int *binary, char **file_name)
 771 {
 772   bool escaped_filename = false;
 773   size_t algo_name_len;
 774
 775   size_t i = 0;
 776   while (ISWHITE (s[i]))
 777     ++i;
 778
 779   if (s[i] == '\\')
 780     {
 781       ++i;
 782       escaped_filename = true;
 783     }
 784
 785   /* Check for BSD-style checksum line. */
 786
 787 #if HASH_ALGO_CKSUM
 788   if (! algorithm_specified)
 789     {
 790       ptrdiff_t algo_tag = algorithm_from_tag (s + i);
 791       if (algo_tag >= 0)
 792         {
 793           if (algo_tag <= crc)
 794             return false;  /* We don't support checking these older formats.  */
 795           cksum_algorithm = algo_tag;
 796         }
 797       else
 798         return false;  /* We only support tagged format without -a.  */
 799     }
 800 #endif
 801
 802   algo_name_len = strlen (DIGEST_TYPE_STRING);
 803   if (STREQ_LEN (s + i, DIGEST_TYPE_STRING, algo_name_len))
 804     {
 805       i += algo_name_len;
 806 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 807       /* Terminate and match algorithm name.  */
 808       char const *algo_name = &s[i - algo_name_len];
 809       bool length_specified = s[i] == '-';
 810       bool openssl_format = s[i] == '('; /* and no length_specified */
 811       s[i++] = '\0';
 812       if (!STREQ (algo_name, DIGEST_TYPE_STRING))
 813         return false;
 814       if (openssl_format)
 815         s[--i] = '(';
 816
 817 # if HASH_ALGO_BLAKE2
 818       digest_length = BLAKE2B_MAX_LEN * 8;
 819 # else
 820       digest_length = algorithm_bits[cksum_algorithm];
 821 # endif
 822       if (length_specified)
 823         {
 824           uintmax_t length;
 825           char *siend;
 826           if (! (xstrtoumax (s + i, &siend, 0, &length, nullptr) == LONGINT_OK
 827                  && 0 < length && length <= digest_length
 828                  && length % 8 == 0))
 829             return false;
 830
 831           i = siend - s;
 832           digest_length = length;
 833         }
 834       digest_hex_bytes = digest_length / 4;
 835 #endif
 836       if (s[i] == ' ')
 837         ++i;
 838       if (s[i] == '(')
 839         {
 840           ++i;
 841           *binary = 0;
 842           return bsd_split_3 (s + i, s_len - i,
 843                               digest, d_len, file_name, escaped_filename);
 844         }
 845       return false;
 846     }
 847
 848   /* Ignore this line if it is too short.
 849      Each line must have at least 'min_digest_line_length - 1' (or one more, if
 850      the first is a backslash) more characters to contain correct message digest
 851      information.  */
 852   if (s_len - i < min_digest_line_length + (s[i] == '\\'))
 853     return false;
 854
 855   *digest = (unsigned char *) &s[i];
 856
 857 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
 858   /* Auto determine length.  */
 859 # if HASH_ALGO_CKSUM
 860   if (cksum_algorithm == blake2b) {
 861 # endif
 862   unsigned char const *hp = *digest;
 863   digest_hex_bytes = 0;
 864   while (c_isxdigit (*hp++))
 865     digest_hex_bytes++;
 866   if (digest_hex_bytes < 2 || digest_hex_bytes % 2
 867       || BLAKE2B_MAX_LEN * 2 < digest_hex_bytes)
 868     return false;
 869   digest_length = digest_hex_bytes * 4;
 870 # if HASH_ALGO_CKSUM
 871   }
 872 # endif
 873 #endif
 874
 875   /* This field must be the hexadecimal or base64 representation
 876      of the message digest.  */
 877   while (s[i] && !ISWHITE (s[i]))
 878     i++;
 879
 880   /* The digest must be followed by at least one whitespace character.  */
 881   if (i == s_len)
 882     return false;
 883
 884   *d_len = &s[i] - (char *) *digest;
 885   s[i++] = '\0';
 886
 887   if (! valid_digits (*digest, *d_len))
 888     return false;
 889
 890   /* If "bsd reversed" format detected.  */
 891   if ((s_len - i == 1) || (s[i] != ' ' && s[i] != '*'))
 892     {
 893       /* Don't allow mixing bsd and standard formats,
 894          to minimize security issues with attackers
 895          renaming files with leading spaces.
 896          This assumes that with bsd format checksums
 897          that the first file name does not have
 898          a leading ' ' or '*'.  */
 899       if (bsd_reversed == 0)
 900         return false;
 901       bsd_reversed = 1;
 902     }
 903   else if (bsd_reversed != 1)
 904     {
 905       bsd_reversed = 0;
 906       *binary = (s[i++] == '*');
 907     }
 908
 909   /* All characters between the type indicator and end of line are
 910      significant -- that includes leading and trailing white space.  */
 911   *file_name = &s[i];
 912
 913   if (escaped_filename)
 914     return filename_unescape (&s[i], s_len - i) != nullptr;
 915
 916   return true;
 917 }
 918
 919 /* If ESCAPE is true, then translate each:
 920    NEWLINE byte to the string, "\\n",
 921    CARRIAGE RETURN byte to the string, "\\r",
 922    and each backslash to "\\\\".  */
 923 static void
 924 print_filename (char const *file, bool escape)
 925 {
 926   if (! escape)
 927     {
 928       fputs (file, stdout);
 929       return;
 930     }
 931
 932   while (*file)
 933     {
 934       switch (*file)
 935         {
 936         case '\n':
 937           fputs ("\\n", stdout);
 938           break;
 939
 940         case '\r':
 941           fputs ("\\r", stdout);
 942           break;
 943
 944         case '\\':
 945           fputs ("\\\\", stdout);
 946           break;
 947
 948         default:
 949           putchar (*file);
 950           break;
 951         }
 952       file++;
 953     }
 954 }
 955
 956 /* An interface to the function, DIGEST_STREAM.
 957    Operate on FILENAME (it may be "-").
 958
 959    *BINARY indicates whether the file is binary.  BINARY < 0 means it
 960    depends on whether binary mode makes any difference and the file is
 961    a terminal; in that case, clear *BINARY if the file was treated as
 962    text because it was a terminal.
 963
 964    Put the checksum in *BIN_RESULT, which must be properly aligned.
 965    Put true in *MISSING if the file can't be opened due to ENOENT.
 966    Return true if successful.  */
 967
 968 static bool
 969 digest_file (char const *filename, int *binary, unsigned char *bin_result,
 970              bool *missing, MAYBE_UNUSED uintmax_t *length)
 971 {
 972   FILE *fp;
 973   int err;
 974   bool is_stdin = STREQ (filename, "-");
 975
 976   *missing = false;
 977
 978   if (is_stdin)
 979     {
 980       have_read_stdin = true;
 981       fp = stdin;
 982       if (O_BINARY && *binary)
 983         {
 984           if (*binary < 0)
 985             *binary = ! isatty (STDIN_FILENO);
 986           if (*binary)
 987             xset_binary_mode (STDIN_FILENO, O_BINARY);
 988         }
 989     }
 990   else
 991     {
 992       fp = fopen (filename, (O_BINARY && *binary ? "rb" : "r"));
 993       if (fp == nullptr)
 994         {
 995           if (ignore_missing && errno == ENOENT)
 996             {
 997               *missing = true;
 998               return true;
 999             }
1000           error (0, errno, "%s", quotef (filename));
1001           return false;
1002         }
1003     }
1004
1005   fadvise (fp, FADVISE_SEQUENTIAL);
1006
1007 #if HASH_ALGO_CKSUM
1008   if (cksum_algorithm == blake2b)
1009     *length = digest_length / 8;
1010   err = DIGEST_STREAM (fp, bin_result, length);
1011 #elif HASH_ALGO_SUM
1012   err = DIGEST_STREAM (fp, bin_result, length);
1013 #elif HASH_ALGO_BLAKE2
1014   err = DIGEST_STREAM (fp, bin_result, digest_length / 8);
1015 #else
1016   err = DIGEST_STREAM (fp, bin_result);
1017 #endif
1018   err = err ? errno : 0;
1019   if (is_stdin)
1020     clearerr (fp);
1021   else if (fclose (fp) != 0 && !err)
1022     err = errno;
1023
1024   if (err)
1025     {
1026       error (0, err, "%s", quotef (filename));
1027       return false;
1028     }
1029
1030   return true;
1031 }
1032
1033 #if !HASH_ALGO_SUM
1034 static void
1035 output_file (char const *file, int binary_file, void const *digest,
1036              bool raw, bool tagged, unsigned char delim, MAYBE_UNUSED bool args,
1037              MAYBE_UNUSED uintmax_t length)
1038 {
1039 # if HASH_ALGO_CKSUM
1040   if (raw)
1041     {
1042       fwrite (digest, 1, digest_length / 8, stdout);
1043       return;
1044     }
1045 # endif
1046
1047   unsigned char const *bin_buffer = digest;
1048
1049   /* Output a leading backslash if the file name contains problematic chars.  */
1050   bool needs_escape = delim == '\n' && problematic_chars (file);
1051
1052   if (needs_escape)
1053     putchar ('\\');
1054
1055   if (tagged)
1056     {
1057       fputs (DIGEST_TYPE_STRING, stdout);
1058 # if HASH_ALGO_BLAKE2
1059       if (digest_length < BLAKE2B_MAX_LEN * 8)
1060         printf ("-%ju", digest_length);
1061 # elif HASH_ALGO_CKSUM
1062       if (cksum_algorithm == blake2b)
1063         {
1064           if (digest_length < BLAKE2B_MAX_LEN * 8)
1065             printf ("-%ju", digest_length);
1066         }
1067 # endif
1068       fputs (" (", stdout);
1069       print_filename (file, needs_escape);
1070       fputs (") = ", stdout);
1071     }
1072
1073 # if HASH_ALGO_CKSUM
1074   if (base64_digest)
1075     {
1076       char b64[BASE64_LENGTH (DIGEST_BIN_BYTES) + 1];
1077       base64_encode ((char const *) bin_buffer, digest_length / 8,
1078                      b64, sizeof b64);
1079       fputs (b64, stdout);
1080     }
1081   else
1082 # endif
1083     {
1084       for (size_t i = 0; i < (digest_hex_bytes / 2); ++i)
1085         printf ("%02x", bin_buffer[i]);
1086     }
1087
1088   if (!tagged)
1089     {
1090       putchar (' ');
1091       putchar (binary_file ? '*' : ' ');
1092       print_filename (file, needs_escape);
1093     }
1094
1095   putchar (delim);
1096 }
1097 #endif
1098
1099 #if HASH_ALGO_CKSUM
1100 /* Return true if B64_DIGEST is the same as the base64 digest of the
1101    DIGEST_LENGTH/8 bytes at BIN_BUFFER.  */
1102 static bool
1103 b64_equal (unsigned char const *b64_digest, unsigned char const *bin_buffer)
1104 {
1105   size_t b64_n_bytes = BASE64_LENGTH (digest_length / 8);
1106   char b64[BASE64_LENGTH (DIGEST_BIN_BYTES) + 1];
1107   base64_encode ((char const *) bin_buffer, digest_length / 8, b64, sizeof b64);
1108   return memcmp (b64_digest, b64, b64_n_bytes + 1) == 0;
1109 }
1110 #endif
1111
1112 /* Return true if HEX_DIGEST is the same as the hex-encoded digest of the
1113    DIGEST_LENGTH/8 bytes at BIN_BUFFER.  */
1114 static bool
1115 hex_equal (unsigned char const *hex_digest, unsigned char const *bin_buffer)
1116 {
1117   static const char bin2hex[] = { '0', '1', '2', '3',
1118                                   '4', '5', '6', '7',
1119                                   '8', '9', 'a', 'b',
1120                                   'c', 'd', 'e', 'f' };
1121   size_t digest_bin_bytes = digest_hex_bytes / 2;
1122
1123   /* Compare generated binary number with text representation
1124      in check file.  Ignore case of hex digits.  */
1125   size_t cnt;
1126   for (cnt = 0; cnt < digest_bin_bytes; ++cnt)
1127     {
1128       if (c_tolower (hex_digest[2 * cnt])
1129           != bin2hex[bin_buffer[cnt] >> 4]
1130           || (c_tolower (hex_digest[2 * cnt + 1])
1131               != (bin2hex[bin_buffer[cnt] & 0xf])))
1132         break;
1133     }
1134   return cnt == digest_bin_bytes;
1135 }
1136
1137 static bool
1138 digest_check (char const *checkfile_name)
1139 {
1140   FILE *checkfile_stream;
1141   uintmax_t n_misformatted_lines = 0;
1142   uintmax_t n_mismatched_checksums = 0;
1143   uintmax_t n_open_or_read_failures = 0;
1144   bool properly_formatted_lines = false;
1145   bool matched_checksums = false;
1146   unsigned char bin_buffer_unaligned[DIGEST_BIN_BYTES + DIGEST_ALIGN];
1147   /* Make sure bin_buffer is properly aligned. */
1148   unsigned char *bin_buffer = ptr_align (bin_buffer_unaligned, DIGEST_ALIGN);
1149   uintmax_t line_number;
1150   char *line;
1151   size_t line_chars_allocated;
1152   bool is_stdin = STREQ (checkfile_name, "-");
1153
1154   if (is_stdin)
1155     {
1156       have_read_stdin = true;
1157       checkfile_name = _("standard input");
1158       checkfile_stream = stdin;
1159     }
1160   else
1161     {
1162       checkfile_stream = fopen (checkfile_name, "r");
1163       if (checkfile_stream == nullptr)
1164         {
1165           error (0, errno, "%s", quotef (checkfile_name));
1166           return false;
1167         }
1168     }
1169
1170   line_number = 0;
1171   line = nullptr;
1172   line_chars_allocated = 0;
1173   do
1174     {
1175       char *filename;
1176       int binary;
1177       unsigned char *digest;
1178       ssize_t line_length;
1179
1180       ++line_number;
1181       if (line_number == 0)
1182         error (EXIT_FAILURE, 0, _("%s: too many checksum lines"),
1183                quotef (checkfile_name));
1184
1185       line_length = getline (&line, &line_chars_allocated, checkfile_stream);
1186       if (line_length <= 0)
1187         break;
1188
1189       /* Ignore comment lines, which begin with a '#' character.  */
1190       if (line[0] == '#')
1191         continue;
1192
1193       /* Remove any trailing newline.  */
1194       line_length -= line[line_length - 1] == '\n';
1195       /* Remove any trailing carriage return.  */
1196       line_length -= line[line_length - (0 < line_length)] == '\r';
1197
1198       /* Ignore empty lines.  */
1199       if (line_length == 0)
1200         continue;
1201
1202       line[line_length] = '\0';
1203
1204       size_t d_len;
1205       if (! (split_3 (line, line_length, &digest, &d_len, &binary, &filename)
1206              && ! (is_stdin && STREQ (filename, "-"))))
1207         {
1208           ++n_misformatted_lines;
1209
1210           if (warn)
1211             {
1212               error (0, 0,
1213                      _("%s: %ju"
1214                        ": improperly formatted %s checksum line"),
1215                      quotef (checkfile_name), line_number,
1216                      DIGEST_TYPE_STRING);
1217             }
1218         }
1219       else
1220         {
1221           bool ok;
1222           bool missing;
1223           bool needs_escape = ! status_only && problematic_chars (filename);
1224
1225           properly_formatted_lines = true;
1226
1227           uintmax_t length;
1228           ok = digest_file (filename, &binary, bin_buffer, &missing, &length);
1229
1230           if (!ok)
1231             {
1232               ++n_open_or_read_failures;
1233               if (!status_only)
1234                 {
1235                   if (needs_escape)
1236                     putchar ('\\');
1237                   print_filename (filename, needs_escape);
1238                   printf (": %s\n", _("FAILED open or read"));
1239                 }
1240             }
1241           else if (ignore_missing && missing)
1242             {
1243               /* Ignore missing files with --ignore-missing.  */
1244               ;
1245             }
1246           else
1247             {
1248               bool match = false;
1249 #if HASH_ALGO_CKSUM
1250               if (d_len < digest_hex_bytes)
1251                 match = b64_equal (digest, bin_buffer);
1252               else
1253 #endif
1254                 if (d_len == digest_hex_bytes)
1255                   match = hex_equal (digest, bin_buffer);
1256
1257               if (match)
1258                 matched_checksums = true;
1259               else
1260                 ++n_mismatched_checksums;
1261
1262               if (!status_only)
1263                 {
1264                   if (! match || ! quiet)
1265                     {
1266                       if (needs_escape)
1267                         putchar ('\\');
1268                       print_filename (filename, needs_escape);
1269                     }
1270
1271                   if (! match)
1272                     printf (": %s\n", _("FAILED"));
1273                   else if (!quiet)
1274                     printf (": %s\n", _("OK"));
1275                 }
1276             }
1277         }
1278     }
1279   while (!feof (checkfile_stream) && !ferror (checkfile_stream));
1280
1281   free (line);
1282
1283   int err = ferror (checkfile_stream) ? 0 : -1;
1284   if (is_stdin)
1285     clearerr (checkfile_stream);
1286   else if (fclose (checkfile_stream) != 0 && err < 0)
1287     err = errno;
1288
1289   if (0 <= err)
1290     {
1291       error (0, err, err ? "%s" : _("%s: read error"),
1292              quotef (checkfile_name));
1293       return false;
1294     }
1295
1296   if (! properly_formatted_lines)
1297     {
1298       /* Warn if no tests are found.  */
1299       error (0, 0, _("%s: no properly formatted checksum lines found"),
1300              quotef (checkfile_name));
1301     }
1302   else
1303     {
1304       if (!status_only)
1305         {
1306           if (n_misformatted_lines != 0)
1307             error (0, 0,
1308                    (ngettext
1309                     ("WARNING: %ju line is improperly formatted",
1310                      "WARNING: %ju lines are improperly formatted",
1311                      select_plural (n_misformatted_lines))),
1312                    n_misformatted_lines);
1313
1314           if (n_open_or_read_failures != 0)
1315             error (0, 0,
1316                    (ngettext
1317                     ("WARNING: %ju listed file could not be read",
1318                      "WARNING: %ju listed files could not be read",
1319                      select_plural (n_open_or_read_failures))),
1320                    n_open_or_read_failures);
1321
1322           if (n_mismatched_checksums != 0)
1323             error (0, 0,
1324                    (ngettext
1325                     ("WARNING: %ju computed checksum did NOT match",
1326                      "WARNING: %ju computed checksums did NOT match",
1327                      select_plural (n_mismatched_checksums))),
1328                    n_mismatched_checksums);
1329
1330           if (ignore_missing && ! matched_checksums)
1331             error (0, 0, _("%s: no file was verified"),
1332                    quotef (checkfile_name));
1333         }
1334     }
1335
1336   return (properly_formatted_lines
1337           && matched_checksums
1338           && n_mismatched_checksums == 0
1339           && n_open_or_read_failures == 0
1340           && (!strict || n_misformatted_lines == 0));
1341 }
1342
1343 int
1344 main (int argc, char **argv)
1345 {
1346   unsigned char bin_buffer_unaligned[DIGEST_BIN_BYTES + DIGEST_ALIGN];
1347   /* Make sure bin_buffer is properly aligned. */
1348   unsigned char *bin_buffer = ptr_align (bin_buffer_unaligned, DIGEST_ALIGN);
1349   bool do_check = false;
1350   int opt;
1351   bool ok = true;
1352   int binary = -1;
1353   int prefix_tag = -1;
1354
1355   /* Setting values of global variables.  */
1356   initialize_main (&argc, &argv);
1357   set_program_name (argv[0]);
1358   setlocale (LC_ALL, "");
1359   bindtextdomain (PACKAGE, LOCALEDIR);
1360   textdomain (PACKAGE);
1361
1362   atexit (close_stdout);
1363
1364   /* Line buffer stdout to ensure lines are written atomically and immediately
1365      so that processes running in parallel do not intersperse their output.  */
1366   setvbuf (stdout, nullptr, _IOLBF, 0);
1367
1368 #if HASH_ALGO_SUM
1369   char const *short_opts = "rs";
1370 #elif HASH_ALGO_CKSUM
1371   char const *short_opts = "a:l:bctwz";
1372   char const *digest_length_str = "";
1373 #elif HASH_ALGO_BLAKE2
1374   char const *short_opts = "l:bctwz";
1375   char const *digest_length_str = "";
1376 #else
1377   char const *short_opts = "bctwz";
1378 #endif
1379
1380   while ((opt = getopt_long (argc, argv, short_opts, long_options, nullptr))
1381          != -1)
1382     switch (opt)
1383       {
1384 #if HASH_ALGO_CKSUM
1385       case 'a':
1386         cksum_algorithm = XARGMATCH_EXACT ("--algorithm", optarg,
1387                                            algorithm_args, algorithm_types);
1388         algorithm_specified = true;
1389         break;
1390
1391       case DEBUG_PROGRAM_OPTION:
1392         cksum_debug = true;
1393         break;
1394 #endif
1395 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
1396       case 'l':
1397         digest_length = xnumtoumax (optarg, 10, 0, BLAKE2B_MAX_LEN * 8, "",
1398                                     _("invalid length"), 0,
1399                                     XTOINT_MAX_QUIET);
1400         digest_length_str = optarg;
1401         break;
1402 #endif
1403 #if !HASH_ALGO_SUM
1404       case 'c':
1405         do_check = true;
1406         break;
1407       case STATUS_OPTION:
1408         status_only = true;
1409         warn = false;
1410         quiet = false;
1411         break;
1412       case 'b':
1413         binary = 1;
1414         break;
1415       case 't':
1416         binary = 0;
1417         break;
1418       case 'w':
1419         status_only = false;
1420         warn = true;
1421         quiet = false;
1422         break;
1423       case IGNORE_MISSING_OPTION:
1424         ignore_missing = true;
1425         break;
1426       case QUIET_OPTION:
1427         status_only = false;
1428         warn = false;
1429         quiet = true;
1430         break;
1431       case STRICT_OPTION:
1432         strict = true;
1433         break;
1434 # if HASH_ALGO_CKSUM
1435       case BASE64_OPTION:
1436         base64_digest = true;
1437         break;
1438       case RAW_OPTION:
1439         raw_digest = true;
1440         break;
1441       case UNTAG_OPTION:
1442         if (prefix_tag == 1)
1443           binary = -1;
1444         prefix_tag = 0;
1445         break;
1446 # endif
1447       case TAG_OPTION:
1448         prefix_tag = 1;
1449         binary = 1;
1450         break;
1451       case 'z':
1452         digest_delim = '\0';
1453         break;
1454 #endif
1455 #if HASH_ALGO_SUM
1456       case 'r':         /* For SysV compatibility. */
1457         sum_algorithm = bsd;
1458         break;
1459
1460       case 's':
1461         sum_algorithm = sysv;
1462         break;
1463 #endif
1464       case_GETOPT_HELP_CHAR;
1465       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
1466       default:
1467         usage (EXIT_FAILURE);
1468       }
1469
1470   min_digest_line_length = MIN_DIGEST_LINE_LENGTH;
1471 #if HASH_ALGO_BLAKE2 || HASH_ALGO_CKSUM
1472 # if HASH_ALGO_CKSUM
1473   if (digest_length && cksum_algorithm != blake2b)
1474     error (EXIT_FAILURE, 0,
1475            _("--length is only supported with --algorithm=blake2b"));
1476 # endif
1477   if (digest_length > BLAKE2B_MAX_LEN * 8)
1478     {
1479       error (0, 0, _("invalid length: %s"), quote (digest_length_str));
1480       error (EXIT_FAILURE, 0,
1481              _("maximum digest length for %s is %d bits"),
1482              quote (DIGEST_TYPE_STRING),
1483              BLAKE2B_MAX_LEN * 8);
1484     }
1485   if (digest_length % 8 != 0)
1486     {
1487       error (0, 0, _("invalid length: %s"), quote (digest_length_str));
1488       error (EXIT_FAILURE, 0, _("length is not a multiple of 8"));
1489     }
1490   if (digest_length == 0)
1491     {
1492 # if HASH_ALGO_BLAKE2
1493       digest_length = BLAKE2B_MAX_LEN * 8;
1494 # else
1495       digest_length = algorithm_bits[cksum_algorithm];
1496 # endif
1497     }
1498   digest_hex_bytes = digest_length / 4;
1499 #else
1500   digest_hex_bytes = DIGEST_HEX_BYTES;
1501 #endif
1502
1503 #if HASH_ALGO_CKSUM
1504   switch (cksum_algorithm)
1505     {
1506     case bsd:
1507     case sysv:
1508     case crc:
1509         if (do_check && algorithm_specified)
1510           error (EXIT_FAILURE, 0,
1511                  _("--check is not supported with --algorithm={bsd,sysv,crc}"));
1512         break;
1513     default:
1514         break;
1515     }
1516
1517   if (base64_digest && raw_digest)
1518    {
1519      error (0, 0, _("--base64 and --raw are mutually exclusive"));
1520      usage (EXIT_FAILURE);
1521    }
1522 #endif
1523
1524   if (prefix_tag == -1)
1525     prefix_tag = HASH_ALGO_CKSUM;
1526
1527   if (prefix_tag && !binary)
1528    {
1529      /* This could be supported in a backwards compatible way
1530         by prefixing the output line with a space in text mode.
1531         However that's invasive enough that it was agreed to
1532         not support this mode with --tag, as --text use cases
1533         are adequately supported by the default output format.  */
1534 #if !HASH_ALGO_CKSUM
1535      error (0, 0, _("--tag does not support --text mode"));
1536 #else
1537      error (0, 0, _("--text mode is only supported with --untagged"));
1538 #endif
1539      usage (EXIT_FAILURE);
1540    }
1541
1542   if (digest_delim != '\n' && do_check)
1543     {
1544       error (0, 0, _("the --zero option is not supported when "
1545                      "verifying checksums"));
1546       usage (EXIT_FAILURE);
1547     }
1548 #if !HASH_ALGO_CKSUM
1549   if (prefix_tag && do_check)
1550     {
1551       error (0, 0, _("the --tag option is meaningless when "
1552                      "verifying checksums"));
1553       usage (EXIT_FAILURE);
1554     }
1555 #endif
1556
1557   if (0 <= binary && do_check)
1558     {
1559       error (0, 0, _("the --binary and --text options are meaningless when "
1560                      "verifying checksums"));
1561       usage (EXIT_FAILURE);
1562     }
1563
1564   if (ignore_missing && !do_check)
1565     {
1566       error (0, 0,
1567              _("the --ignore-missing option is meaningful only when "
1568                "verifying checksums"));
1569       usage (EXIT_FAILURE);
1570     }
1571
1572   if (status_only && !do_check)
1573     {
1574       error (0, 0,
1575        _("the --status option is meaningful only when verifying checksums"));
1576       usage (EXIT_FAILURE);
1577     }
1578
1579   if (warn && !do_check)
1580     {
1581       error (0, 0,
1582        _("the --warn option is meaningful only when verifying checksums"));
1583       usage (EXIT_FAILURE);
1584     }
1585
1586   if (quiet && !do_check)
1587     {
1588       error (0, 0,
1589        _("the --quiet option is meaningful only when verifying checksums"));
1590       usage (EXIT_FAILURE);
1591     }
1592
1593   if (strict & !do_check)
1594    {
1595      error (0, 0,
1596         _("the --strict option is meaningful only when verifying checksums"));
1597      usage (EXIT_FAILURE);
1598    }
1599
1600   if (!O_BINARY && binary < 0)
1601     binary = 0;
1602
1603   char **operand_lim = argv + argc;
1604   if (optind == argc)
1605     *operand_lim++ = bad_cast ("-");
1606   else if (1 < argc - optind && raw_digest)
1607     error (EXIT_FAILURE, 0,
1608            _("the --raw option is not supported with multiple files"));
1609
1610   for (char **operandp = argv + optind; operandp < operand_lim; operandp++)
1611     {
1612       char *file = *operandp;
1613       if (do_check)
1614         ok &= digest_check (file);
1615       else
1616         {
1617           int binary_file = binary;
1618           bool missing;
1619           uintmax_t length;
1620
1621           if (! digest_file (file, &binary_file, bin_buffer, &missing, &length))
1622             ok = false;
1623           else
1624             {
1625               DIGEST_OUT (file, binary_file, bin_buffer, raw_digest, prefix_tag,
1626                           digest_delim, optind != argc, length);
1627             }
1628         }
1629     }
1630
1631   if (have_read_stdin && fclose (stdin) == EOF)
1632     error (EXIT_FAILURE, errno, _("standard input"));
1633
1634   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
1635 }