src/md5sum.c

   1 /* Compute checksums of files or strings.
   2    Copyright (C) 1995-2016 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 <http://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
  26 #if HASH_ALGO_MD5
  27 # include "md5.h"
  28 #endif
  29 #if HASH_ALGO_SHA1
  30 # include "sha1.h"
  31 #endif
  32 #if HASH_ALGO_SHA256 || HASH_ALGO_SHA224
  33 # include "sha256.h"
  34 #endif
  35 #if HASH_ALGO_SHA512 || HASH_ALGO_SHA384
  36 # include "sha512.h"
  37 #endif
  38 #include "error.h"
  39 #include "fadvise.h"
  40 #include "stdio--.h"
  41 #include "xfreopen.h"
  42
  43 /* The official name of this program (e.g., no 'g' prefix).  */
  44 #if HASH_ALGO_MD5
  45 # define PROGRAM_NAME "md5sum"
  46 # define DIGEST_TYPE_STRING "MD5"
  47 # define DIGEST_STREAM md5_stream
  48 # define DIGEST_BITS 128
  49 # define DIGEST_REFERENCE "RFC 1321"
  50 # define DIGEST_ALIGN 4
  51 #elif HASH_ALGO_SHA1
  52 # define PROGRAM_NAME "sha1sum"
  53 # define DIGEST_TYPE_STRING "SHA1"
  54 # define DIGEST_STREAM sha1_stream
  55 # define DIGEST_BITS 160
  56 # define DIGEST_REFERENCE "FIPS-180-1"
  57 # define DIGEST_ALIGN 4
  58 #elif HASH_ALGO_SHA256
  59 # define PROGRAM_NAME "sha256sum"
  60 # define DIGEST_TYPE_STRING "SHA256"
  61 # define DIGEST_STREAM sha256_stream
  62 # define DIGEST_BITS 256
  63 # define DIGEST_REFERENCE "FIPS-180-2"
  64 # define DIGEST_ALIGN 4
  65 #elif HASH_ALGO_SHA224
  66 # define PROGRAM_NAME "sha224sum"
  67 # define DIGEST_TYPE_STRING "SHA224"
  68 # define DIGEST_STREAM sha224_stream
  69 # define DIGEST_BITS 224
  70 # define DIGEST_REFERENCE "RFC 3874"
  71 # define DIGEST_ALIGN 4
  72 #elif HASH_ALGO_SHA512
  73 # define PROGRAM_NAME "sha512sum"
  74 # define DIGEST_TYPE_STRING "SHA512"
  75 # define DIGEST_STREAM sha512_stream
  76 # define DIGEST_BITS 512
  77 # define DIGEST_REFERENCE "FIPS-180-2"
  78 # define DIGEST_ALIGN 8
  79 #elif HASH_ALGO_SHA384
  80 # define PROGRAM_NAME "sha384sum"
  81 # define DIGEST_TYPE_STRING "SHA384"
  82 # define DIGEST_STREAM sha384_stream
  83 # define DIGEST_BITS 384
  84 # define DIGEST_REFERENCE "FIPS-180-2"
  85 # define DIGEST_ALIGN 8
  86 #else
  87 # error "Can't decide which hash algorithm to compile."
  88 #endif
  89
  90 #define DIGEST_HEX_BYTES (DIGEST_BITS / 4)
  91 #define DIGEST_BIN_BYTES (DIGEST_BITS / 8)
  92
  93 #define AUTHORS \
  94   proper_name ("Ulrich Drepper"), \
  95   proper_name ("Scott Miller"), \
  96   proper_name ("David Madore")
  97
  98 /* The minimum length of a valid digest line.  This length does
  99    not include any newline character at the end of a line.  */
 100 #define MIN_DIGEST_LINE_LENGTH \
 101   (DIGEST_HEX_BYTES /* length of hexadecimal message digest */ \
 102    + 1 /* blank */ \
 103    + 1 /* minimum filename length */ )
 104
 105 /* True if any of the files read were the standard input. */
 106 static bool have_read_stdin;
 107
 108 /* The minimum length of a valid checksum line for the selected algorithm.  */
 109 static size_t min_digest_line_length;
 110
 111 /* Set to the length of a digest hex string for the selected algorithm.  */
 112 static size_t digest_hex_bytes;
 113
 114 /* With --check, don't generate any output.
 115    The exit code indicates success or failure.  */
 116 static bool status_only = false;
 117
 118 /* With --check, print a message to standard error warning about each
 119    improperly formatted checksum line.  */
 120 static bool warn = false;
 121
 122 /* With --check, ignore missing files.  */
 123 static bool ignore_missing = false;
 124
 125 /* With --check, suppress the "OK" printed for each verified file.  */
 126 static bool quiet = false;
 127
 128 /* With --check, exit with a non-zero return code if any line is
 129    improperly formatted. */
 130 static bool strict = false;
 131
 132 /* Whether a BSD reversed format checksum is detected.  */
 133 static int bsd_reversed = -1;
 134
 135 /* For long options that have no equivalent short option, use a
 136    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
 137 enum
 138 {
 139   IGNORE_MISSING_OPTION = CHAR_MAX + 1,
 140   STATUS_OPTION,
 141   QUIET_OPTION,
 142   STRICT_OPTION,
 143   TAG_OPTION
 144 };
 145
 146 static struct option const long_options[] =
 147 {
 148   { "binary", no_argument, NULL, 'b' },
 149   { "check", no_argument, NULL, 'c' },
 150   { "ignore-missing", no_argument, NULL, IGNORE_MISSING_OPTION},
 151   { "quiet", no_argument, NULL, QUIET_OPTION },
 152   { "status", no_argument, NULL, STATUS_OPTION },
 153   { "text", no_argument, NULL, 't' },
 154   { "warn", no_argument, NULL, 'w' },
 155   { "strict", no_argument, NULL, STRICT_OPTION },
 156   { "tag", no_argument, NULL, TAG_OPTION },
 157   { GETOPT_HELP_OPTION_DECL },
 158   { GETOPT_VERSION_OPTION_DECL },
 159   { NULL, 0, NULL, 0 }
 160 };
 161
 162 void
 163 usage (int status)
 164 {
 165   if (status != EXIT_SUCCESS)
 166     emit_try_help ();
 167   else
 168     {
 169       printf (_("\
 170 Usage: %s [OPTION]... [FILE]...\n\
 171 Print or check %s (%d-bit) checksums.\n\
 172 "),
 173               program_name,
 174               DIGEST_TYPE_STRING,
 175               DIGEST_BITS);
 176
 177       emit_stdin_note ();
 178
 179       if (O_BINARY)
 180         fputs (_("\
 181 \n\
 182   -b, --binary         read in binary mode (default unless reading tty stdin)\n\
 183 "), stdout);
 184       else
 185         fputs (_("\
 186 \n\
 187   -b, --binary         read in binary mode\n\
 188 "), stdout);
 189       printf (_("\
 190   -c, --check          read %s sums from the FILEs and check them\n"),
 191               DIGEST_TYPE_STRING);
 192       fputs (_("\
 193       --tag            create a BSD-style checksum\n\
 194 "), stdout);
 195       if (O_BINARY)
 196         fputs (_("\
 197   -t, --text           read in text mode (default if reading tty stdin)\n\
 198 "), stdout);
 199       else
 200         fputs (_("\
 201   -t, --text           read in text mode (default)\n\
 202 "), stdout);
 203       fputs (_("\
 204 \n\
 205 The following five options are useful only when verifying checksums:\n\
 206       --ignore-missing  don't fail or report status for missing files\n\
 207       --quiet          don't print OK for each successfully verified file\n\
 208       --status         don't output anything, status code shows success\n\
 209       --strict         exit non-zero for improperly formatted checksum lines\n\
 210   -w, --warn           warn about improperly formatted checksum lines\n\
 211 \n\
 212 "), stdout);
 213       fputs (HELP_OPTION_DESCRIPTION, stdout);
 214       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 215       printf (_("\
 216 \n\
 217 The sums are computed as described in %s.  When checking, the input\n\
 218 should be a former output of this program.  The default mode is to print a\n\
 219 line with checksum, a space, a character indicating input mode ('*' for binary,\
 220 \n' ' for text or where binary is insignificant), and name for each FILE.\n"),
 221               DIGEST_REFERENCE);
 222       emit_ancillary_info (PROGRAM_NAME);
 223     }
 224
 225   exit (status);
 226 }
 227
 228 #define ISWHITE(c) ((c) == ' ' || (c) == '\t')
 229
 230 /* Given a file name, S of length S_LEN, that is not NUL-terminated,
 231    modify it in place, performing the equivalent of this sed substitution:
 232    's/\\n/\n/g;s/\\\\/\\/g' i.e., replacing each "\\n" string with a newline
 233    and each "\\\\" with a single backslash, NUL-terminate it and return S.
 234    If S is not a valid escaped file name, i.e., if it ends with an odd number
 235    of backslashes or if it contains a backslash followed by anything other
 236    than "n" or another backslash, return NULL.  */
 237
 238 static char *
 239 filename_unescape (char *s, size_t s_len)
 240 {
 241   char *dst = s;
 242
 243   for (size_t i = 0; i < s_len; i++)
 244     {
 245       switch (s[i])
 246         {
 247         case '\\':
 248           if (i == s_len - 1)
 249             {
 250               /* File name ends with an unescaped backslash: invalid.  */
 251               return NULL;
 252             }
 253           ++i;
 254           switch (s[i])
 255             {
 256             case 'n':
 257               *dst++ = '\n';
 258               break;
 259             case '\\':
 260               *dst++ = '\\';
 261               break;
 262             default:
 263               /* Only '\' or 'n' may follow a backslash.  */
 264               return NULL;
 265             }
 266           break;
 267
 268         case '\0':
 269           /* The file name may not contain a NUL.  */
 270           return NULL;
 271
 272         default:
 273           *dst++ = s[i];
 274           break;
 275         }
 276     }
 277   if (dst < s + s_len)
 278     *dst = '\0';
 279
 280   return s;
 281 }
 282
 283 /* Split the checksum string S (of length S_LEN) from a BSD 'md5' or
 284    'sha1' command into two parts: a hexadecimal digest, and the file
 285    name.  S is modified.  Return true if successful.  */
 286
 287 static bool
 288 bsd_split_3 (char *s, size_t s_len, unsigned char **hex_digest,
 289              char **file_name, bool escaped_filename)
 290 {
 291   size_t i;
 292
 293   if (s_len == 0)
 294     return false;
 295
 296   /* Find end of filename.  */
 297   i = s_len - 1;
 298   while (i && s[i] != ')')
 299     i--;
 300
 301   if (s[i] != ')')
 302     return false;
 303
 304   *file_name = s;
 305
 306   if (escaped_filename && filename_unescape (s, i) == NULL)
 307     return false;
 308
 309   s[i++] = '\0';
 310
 311   while (ISWHITE (s[i]))
 312     i++;
 313
 314   if (s[i] != '=')
 315     return false;
 316
 317   i++;
 318
 319   while (ISWHITE (s[i]))
 320     i++;
 321
 322   *hex_digest = (unsigned char *) &s[i];
 323   return true;
 324 }
 325
 326 /* Split the string S (of length S_LEN) into three parts:
 327    a hexadecimal digest, binary flag, and the file name.
 328    S is modified.  Return true if successful.  */
 329
 330 static bool
 331 split_3 (char *s, size_t s_len,
 332          unsigned char **hex_digest, int *binary, char **file_name)
 333 {
 334   bool escaped_filename = false;
 335   size_t algo_name_len;
 336
 337   size_t i = 0;
 338   while (ISWHITE (s[i]))
 339     ++i;
 340
 341   if (s[i] == '\\')
 342     {
 343       ++i;
 344       escaped_filename = true;
 345     }
 346
 347   /* Check for BSD-style checksum line. */
 348
 349   algo_name_len = strlen (DIGEST_TYPE_STRING);
 350   if (STREQ_LEN (s + i, DIGEST_TYPE_STRING, algo_name_len))
 351     {
 352       if (s[i + algo_name_len] == ' ')
 353         ++i;
 354       if (s[i + algo_name_len] == '(')
 355         {
 356           *binary = 0;
 357           return bsd_split_3 (s +      i + algo_name_len + 1,
 358                               s_len - (i + algo_name_len + 1),
 359                               hex_digest, file_name, escaped_filename);
 360         }
 361     }
 362
 363   /* Ignore this line if it is too short.
 364      Each line must have at least 'min_digest_line_length - 1' (or one more, if
 365      the first is a backslash) more characters to contain correct message digest
 366      information.  */
 367   if (s_len - i < min_digest_line_length + (s[i] == '\\'))
 368     return false;
 369
 370   *hex_digest = (unsigned char *) &s[i];
 371
 372   /* The first field has to be the n-character hexadecimal
 373      representation of the message digest.  If it is not followed
 374      immediately by a white space it's an error.  */
 375   i += digest_hex_bytes;
 376   if (!ISWHITE (s[i]))
 377     return false;
 378
 379   s[i++] = '\0';
 380
 381   /* If "bsd reversed" format detected.  */
 382   if ((s_len - i == 1) || (s[i] != ' ' && s[i] != '*'))
 383     {
 384       /* Don't allow mixing bsd and standard formats,
 385          to minimize security issues with attackers
 386          renaming files with leading spaces.
 387          This assumes that with bsd format checksums
 388          that the first file name does not have
 389          a leading ' ' or '*'.  */
 390       if (bsd_reversed == 0)
 391         return false;
 392       bsd_reversed = 1;
 393     }
 394   else if (bsd_reversed != 1)
 395     {
 396       bsd_reversed = 0;
 397       *binary = (s[i++] == '*');
 398     }
 399
 400   /* All characters between the type indicator and end of line are
 401      significant -- that includes leading and trailing white space.  */
 402   *file_name = &s[i];
 403
 404   if (escaped_filename)
 405     return filename_unescape (&s[i], s_len - i) != NULL;
 406
 407   return true;
 408 }
 409
 410 /* Return true if S is a NUL-terminated string of DIGEST_HEX_BYTES hex digits.
 411    Otherwise, return false.  */
 412 static bool _GL_ATTRIBUTE_PURE
 413 hex_digits (unsigned char const *s)
 414 {
 415   unsigned int i;
 416   for (i = 0; i < digest_hex_bytes; i++)
 417     {
 418       if (!isxdigit (*s))
 419         return false;
 420       ++s;
 421     }
 422   return *s == '\0';
 423 }
 424
 425 /* If ESCAPE is true, then translate each NEWLINE byte to the string, "\\n",
 426    and each backslash to "\\\\".  */
 427 static void
 428 print_filename (char const *file, bool escape)
 429 {
 430   if (! escape)
 431     {
 432       fputs (file, stdout);
 433       return;
 434     }
 435
 436   while (*file)
 437     {
 438       switch (*file)
 439         {
 440         case '\n':
 441           fputs ("\\n", stdout);
 442           break;
 443
 444         case '\\':
 445           fputs ("\\\\", stdout);
 446           break;
 447
 448         default:
 449           putchar (*file);
 450           break;
 451         }
 452       file++;
 453     }
 454 }
 455
 456 /* An interface to the function, DIGEST_STREAM.
 457    Operate on FILENAME (it may be "-").
 458
 459    *BINARY indicates whether the file is binary.  BINARY < 0 means it
 460    depends on whether binary mode makes any difference and the file is
 461    a terminal; in that case, clear *BINARY if the file was treated as
 462    text because it was a terminal.
 463
 464    Put the checksum in *BIN_RESULT, which must be properly aligned.
 465    Return true if successful.  */
 466
 467 static bool
 468 digest_file (const char *filename, int *binary, unsigned char *bin_result)
 469 {
 470   FILE *fp;
 471   int err;
 472   bool is_stdin = STREQ (filename, "-");
 473
 474   if (is_stdin)
 475     {
 476       have_read_stdin = true;
 477       fp = stdin;
 478       if (O_BINARY && *binary)
 479         {
 480           if (*binary < 0)
 481             *binary = ! isatty (STDIN_FILENO);
 482           if (*binary)
 483             xfreopen (NULL, "rb", stdin);
 484         }
 485     }
 486   else
 487     {
 488       fp = fopen (filename, (O_BINARY && *binary ? "rb" : "r"));
 489       if (fp == NULL)
 490         {
 491           if (ignore_missing && errno == ENOENT)
 492             {
 493               *bin_result = '\0';
 494               return true;
 495             }
 496           error (0, errno, "%s", quotef (filename));
 497           return false;
 498         }
 499     }
 500
 501   fadvise (fp, FADVISE_SEQUENTIAL);
 502
 503   err = DIGEST_STREAM (fp, bin_result);
 504   if (err)
 505     {
 506       error (0, errno, "%s", quotef (filename));
 507       if (fp != stdin)
 508         fclose (fp);
 509       return false;
 510     }
 511
 512   if (!is_stdin && fclose (fp) != 0)
 513     {
 514       error (0, errno, "%s", quotef (filename));
 515       return false;
 516     }
 517
 518   return true;
 519 }
 520
 521 static bool
 522 digest_check (const char *checkfile_name)
 523 {
 524   FILE *checkfile_stream;
 525   uintmax_t n_misformatted_lines = 0;
 526   uintmax_t n_improperly_formatted_lines = 0;
 527   uintmax_t n_mismatched_checksums = 0;
 528   uintmax_t n_open_or_read_failures = 0;
 529   bool properly_formatted_lines = false;
 530   bool matched_checksums = false;
 531   unsigned char bin_buffer_unaligned[DIGEST_BIN_BYTES + DIGEST_ALIGN];
 532   /* Make sure bin_buffer is properly aligned. */
 533   unsigned char *bin_buffer = ptr_align (bin_buffer_unaligned, DIGEST_ALIGN);
 534   uintmax_t line_number;
 535   char *line;
 536   size_t line_chars_allocated;
 537   bool is_stdin = STREQ (checkfile_name, "-");
 538
 539   if (is_stdin)
 540     {
 541       have_read_stdin = true;
 542       checkfile_name = _("standard input");
 543       checkfile_stream = stdin;
 544     }
 545   else
 546     {
 547       checkfile_stream = fopen (checkfile_name, "r");
 548       if (checkfile_stream == NULL)
 549         {
 550           error (0, errno, "%s", quotef (checkfile_name));
 551           return false;
 552         }
 553     }
 554
 555   line_number = 0;
 556   line = NULL;
 557   line_chars_allocated = 0;
 558   do
 559     {
 560       char *filename IF_LINT ( = NULL);
 561       int binary;
 562       unsigned char *hex_digest IF_LINT ( = NULL);
 563       ssize_t line_length;
 564
 565       ++line_number;
 566       if (line_number == 0)
 567         error (EXIT_FAILURE, 0, _("%s: too many checksum lines"),
 568                quotef (checkfile_name));
 569
 570       line_length = getline (&line, &line_chars_allocated, checkfile_stream);
 571       if (line_length <= 0)
 572         break;
 573
 574       /* Ignore comment lines, which begin with a '#' character.  */
 575       if (line[0] == '#')
 576         continue;
 577
 578       /* Remove any trailing newline.  */
 579       if (line[line_length - 1] == '\n')
 580         line[--line_length] = '\0';
 581
 582       if (! (split_3 (line, line_length, &hex_digest, &binary, &filename)
 583              && ! (is_stdin && STREQ (filename, "-"))
 584              && hex_digits (hex_digest)))
 585         {
 586           ++n_misformatted_lines;
 587
 588           if (warn)
 589             {
 590               error (0, 0,
 591                      _("%s: %" PRIuMAX
 592                        ": improperly formatted %s checksum line"),
 593                      quotef (checkfile_name), line_number,
 594                      DIGEST_TYPE_STRING);
 595             }
 596
 597           ++n_improperly_formatted_lines;
 598         }
 599       else
 600         {
 601           static const char bin2hex[] = { '0', '1', '2', '3',
 602                                           '4', '5', '6', '7',
 603                                           '8', '9', 'a', 'b',
 604                                           'c', 'd', 'e', 'f' };
 605           bool ok;
 606           /* Only escape in the edge case producing multiple lines,
 607              to ease automatic processing of status output.  */
 608           bool needs_escape = ! status_only && strchr (filename, '\n');
 609
 610           properly_formatted_lines = true;
 611
 612           *bin_buffer = '\1'; /* flag set to 0 for ignored missing files.  */
 613           ok = digest_file (filename, &binary, bin_buffer);
 614
 615           if (!ok)
 616             {
 617               ++n_open_or_read_failures;
 618               if (!status_only)
 619                 {
 620                   if (needs_escape)
 621                     putchar ('\\');
 622                   print_filename (filename, needs_escape);
 623                   printf (": %s\n", _("FAILED open or read"));
 624                 }
 625             }
 626           else if (ignore_missing && ! *bin_buffer)
 627             {
 628               /* Treat an empty buffer as meaning a missing file,
 629                  which is ignored with --ignore-missing.  */
 630               ;
 631             }
 632           else
 633             {
 634               size_t digest_bin_bytes = digest_hex_bytes / 2;
 635               size_t cnt;
 636
 637               /* Compare generated binary number with text representation
 638                  in check file.  Ignore case of hex digits.  */
 639               for (cnt = 0; cnt < digest_bin_bytes; ++cnt)
 640                 {
 641                   if (tolower (hex_digest[2 * cnt])
 642                       != bin2hex[bin_buffer[cnt] >> 4]
 643                       || (tolower (hex_digest[2 * cnt + 1])
 644                           != (bin2hex[bin_buffer[cnt] & 0xf])))
 645                     break;
 646                 }
 647               if (cnt != digest_bin_bytes)
 648                 ++n_mismatched_checksums;
 649               else
 650                 matched_checksums = true;
 651
 652               if (!status_only)
 653                 {
 654                   if (cnt != digest_bin_bytes || ! quiet)
 655                     {
 656                       if (needs_escape)
 657                         putchar ('\\');
 658                       print_filename (filename, needs_escape);
 659                     }
 660
 661                   if (cnt != digest_bin_bytes)
 662                     printf (": %s\n", _("FAILED"));
 663                   else if (!quiet)
 664                     printf (": %s\n", _("OK"));
 665                 }
 666             }
 667         }
 668     }
 669   while (!feof (checkfile_stream) && !ferror (checkfile_stream));
 670
 671   free (line);
 672
 673   if (ferror (checkfile_stream))
 674     {
 675       error (0, 0, _("%s: read error"), quotef (checkfile_name));
 676       return false;
 677     }
 678
 679   if (!is_stdin && fclose (checkfile_stream) != 0)
 680     {
 681       error (0, errno, "%s", quotef (checkfile_name));
 682       return false;
 683     }
 684
 685   if (! properly_formatted_lines)
 686     {
 687       /* Warn if no tests are found.  */
 688       error (0, 0, _("%s: no properly formatted %s checksum lines found"),
 689              quotef (checkfile_name), DIGEST_TYPE_STRING);
 690     }
 691   else
 692     {
 693       if (!status_only)
 694         {
 695           if (n_misformatted_lines != 0)
 696             error (0, 0,
 697                    (ngettext
 698                     ("WARNING: %" PRIuMAX " line is improperly formatted",
 699                      "WARNING: %" PRIuMAX " lines are improperly formatted",
 700                      select_plural (n_misformatted_lines))),
 701                    n_misformatted_lines);
 702
 703           if (n_open_or_read_failures != 0)
 704             error (0, 0,
 705                    (ngettext
 706                     ("WARNING: %" PRIuMAX " listed file could not be read",
 707                      "WARNING: %" PRIuMAX " listed files could not be read",
 708                      select_plural (n_open_or_read_failures))),
 709                    n_open_or_read_failures);
 710
 711           if (n_mismatched_checksums != 0)
 712             error (0, 0,
 713                    (ngettext
 714                     ("WARNING: %" PRIuMAX " computed checksum did NOT match",
 715                      "WARNING: %" PRIuMAX " computed checksums did NOT match",
 716                      select_plural (n_mismatched_checksums))),
 717                    n_mismatched_checksums);
 718
 719           if (ignore_missing && ! matched_checksums)
 720             error (0, 0, _("%s: no file was verified"),
 721                    quotef (checkfile_name));
 722         }
 723     }
 724
 725   return (properly_formatted_lines
 726           && matched_checksums
 727           && n_mismatched_checksums == 0
 728           && n_open_or_read_failures == 0
 729           && (!strict || n_improperly_formatted_lines == 0));
 730 }
 731
 732 int
 733 main (int argc, char **argv)
 734 {
 735   unsigned char bin_buffer_unaligned[DIGEST_BIN_BYTES + DIGEST_ALIGN];
 736   /* Make sure bin_buffer is properly aligned. */
 737   unsigned char *bin_buffer = ptr_align (bin_buffer_unaligned, DIGEST_ALIGN);
 738   bool do_check = false;
 739   int opt;
 740   bool ok = true;
 741   int binary = -1;
 742   bool prefix_tag = false;
 743
 744   /* Setting values of global variables.  */
 745   initialize_main (&argc, &argv);
 746   set_program_name (argv[0]);
 747   setlocale (LC_ALL, "");
 748   bindtextdomain (PACKAGE, LOCALEDIR);
 749   textdomain (PACKAGE);
 750
 751   atexit (close_stdout);
 752
 753   /* Line buffer stdout to ensure lines are written atomically and immediately
 754      so that processes running in parallel do not intersperse their output.  */
 755   setvbuf (stdout, NULL, _IOLBF, 0);
 756
 757   while ((opt = getopt_long (argc, argv, "bctw", long_options, NULL)) != -1)
 758     switch (opt)
 759       {
 760       case 'b':
 761         binary = 1;
 762         break;
 763       case 'c':
 764         do_check = true;
 765         break;
 766       case STATUS_OPTION:
 767         status_only = true;
 768         warn = false;
 769         quiet = false;
 770         break;
 771       case 't':
 772         binary = 0;
 773         break;
 774       case 'w':
 775         status_only = false;
 776         warn = true;
 777         quiet = false;
 778         break;
 779       case IGNORE_MISSING_OPTION:
 780         ignore_missing = true;
 781         break;
 782       case QUIET_OPTION:
 783         status_only = false;
 784         warn = false;
 785         quiet = true;
 786         break;
 787       case STRICT_OPTION:
 788         strict = true;
 789         break;
 790       case TAG_OPTION:
 791         prefix_tag = true;
 792         binary = 1;
 793         break;
 794       case_GETOPT_HELP_CHAR;
 795       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 796       default:
 797         usage (EXIT_FAILURE);
 798       }
 799
 800   min_digest_line_length = MIN_DIGEST_LINE_LENGTH;
 801   digest_hex_bytes = DIGEST_HEX_BYTES;
 802
 803   if (prefix_tag && !binary)
 804    {
 805      /* This could be supported in a backwards compatible way
 806         by prefixing the output line with a space in text mode.
 807         However that's invasive enough that it was agreed to
 808         not support this mode with --tag, as --text use cases
 809         are adequately supported by the default output format.  */
 810      error (0, 0, _("--tag does not support --text mode"));
 811      usage (EXIT_FAILURE);
 812    }
 813
 814   if (prefix_tag && do_check)
 815     {
 816       error (0, 0, _("the --tag option is meaningless when "
 817                      "verifying checksums"));
 818       usage (EXIT_FAILURE);
 819     }
 820
 821   if (0 <= binary && do_check)
 822     {
 823       error (0, 0, _("the --binary and --text options are meaningless when "
 824                      "verifying checksums"));
 825       usage (EXIT_FAILURE);
 826     }
 827
 828   if (ignore_missing && !do_check)
 829     {
 830       error (0, 0,
 831              _("the --ignore-missing option is meaningful only when "
 832                "verifying checksums"));
 833       usage (EXIT_FAILURE);
 834     }
 835
 836   if (status_only && !do_check)
 837     {
 838       error (0, 0,
 839        _("the --status option is meaningful only when verifying checksums"));
 840       usage (EXIT_FAILURE);
 841     }
 842
 843   if (warn && !do_check)
 844     {
 845       error (0, 0,
 846        _("the --warn option is meaningful only when verifying checksums"));
 847       usage (EXIT_FAILURE);
 848     }
 849
 850   if (quiet && !do_check)
 851     {
 852       error (0, 0,
 853        _("the --quiet option is meaningful only when verifying checksums"));
 854       usage (EXIT_FAILURE);
 855     }
 856
 857   if (strict & !do_check)
 858    {
 859      error (0, 0,
 860         _("the --strict option is meaningful only when verifying checksums"));
 861      usage (EXIT_FAILURE);
 862    }
 863
 864   if (!O_BINARY && binary < 0)
 865     binary = 0;
 866
 867   if (optind == argc)
 868     argv[argc++] = bad_cast ("-");
 869
 870   for (; optind < argc; ++optind)
 871     {
 872       char *file = argv[optind];
 873
 874       if (do_check)
 875         ok &= digest_check (file);
 876       else
 877         {
 878           int file_is_binary = binary;
 879
 880           if (! digest_file (file, &file_is_binary, bin_buffer))
 881             ok = false;
 882           else
 883             {
 884               /* We don't really need to escape, and hence detect, the '\\'
 885                  char, and not doing so should be both forwards and backwards
 886                  compatible, since only escaped lines would have a '\\' char at
 887                  the start.  However just in case users are directly comparing
 888                  against old (hashed) outputs, in the presence of files
 889                  containing '\\' characters, we decided to not simplify the
 890                  output in this case.  */
 891               bool needs_escape = strchr (file, '\\') || strchr (file, '\n');
 892
 893               if (prefix_tag)
 894                 {
 895                   if (needs_escape)
 896                     putchar ('\\');
 897
 898                   fputs (DIGEST_TYPE_STRING, stdout);
 899                   fputs (" (", stdout);
 900                   print_filename (file, needs_escape);
 901                   fputs (") = ", stdout);
 902                 }
 903
 904               size_t i;
 905
 906               /* Output a leading backslash if the file name contains
 907                  a newline or backslash.  */
 908               if (!prefix_tag && needs_escape)
 909                 putchar ('\\');
 910
 911               for (i = 0; i < (digest_hex_bytes / 2); ++i)
 912                 printf ("%02x", bin_buffer[i]);
 913
 914               if (!prefix_tag)
 915                 {
 916                   putchar (' ');
 917
 918                   putchar (file_is_binary ? '*' : ' ');
 919
 920                   print_filename (file, needs_escape);
 921                 }
 922
 923               putchar ('\n');
 924             }
 925         }
 926     }
 927
 928   if (have_read_stdin && fclose (stdin) == EOF)
 929     error (EXIT_FAILURE, errno, _("standard input"));
 930
 931   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 932 }