src/cksum.c

   1 /* cksum -- calculate and print POSIX checksums and sizes of files
   2    Copyright (C) 1992-2019 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 Q. Frank Xia, qx@math.columbia.edu.
  18    Cosmetic changes and reorganization by David MacKenzie, djm@gnu.ai.mit.edu.
  19
  20   Usage: cksum [file...]
  21
  22   The code segment between "#ifdef CRCTAB" and "#else" is the code
  23   which calculates the "crctab". It is included for those who want
  24   verify the correctness of the "crctab". To recreate the "crctab",
  25   do something like the following:
  26
  27       cc -DCRCTAB -o crctab cksum.c
  28       crctab > crctab.h
  29
  30   This software is compatible with neither the System V nor the BSD
  31   'sum' program.  It is supposed to conform to POSIX, except perhaps
  32   for foreign language support.  Any inconsistency with the standard
  33   (other than foreign language support) is a bug.  */
  34
  35 #include <config.h>
  36
  37 /* The official name of this program (e.g., no 'g' prefix).  */
  38 #define PROGRAM_NAME "cksum"
  39
  40 #define AUTHORS proper_name ("Q. Frank Xia")
  41
  42 #include <stdio.h>
  43 #include <sys/types.h>
  44 #include <stdint.h>
  45 #include "system.h"
  46 #include "fadvise.h"
  47 #include "xbinary-io.h"
  48
  49 #ifdef CRCTAB
  50
  51 # define BIT(x) ((uint_fast32_t) 1 << (x))
  52 # define SBIT   BIT (31)
  53
  54 /* The generating polynomial is
  55
  56           32   26   23   22   16   12   11   10   8   7   5   4   2   1
  57     G(X)=X  + X  + X  + X  + X  + X  + X  + X  + X + X + X + X + X + X + 1
  58
  59   The i bit in GEN is set if X^i is a summand of G(X) except X^32.  */
  60
  61 # define GEN    (BIT (26) | BIT (23) | BIT (22) | BIT (16) | BIT (12) \
  62                  | BIT (11) | BIT (10) | BIT (8) | BIT (7) | BIT (5) \
  63                  | BIT (4) | BIT (2) | BIT (1) | BIT (0))
  64
  65 static uint_fast32_t r[8];
  66
  67 static void
  68 fill_r (void)
  69 {
  70   r[0] = GEN;
  71   for (int i = 1; i < 8; i++)
  72     r[i] = (r[i - 1] << 1) ^ ((r[i - 1] & SBIT) ? GEN : 0);
  73 }
  74
  75 static uint_fast32_t
  76 crc_remainder (int m)
  77 {
  78   uint_fast32_t rem = 0;
  79
  80   for (int i = 0; i < 8; i++)
  81     if (BIT (i) & m)
  82       rem ^= r[i];
  83
  84   return rem & 0xFFFFFFFF;      /* Make it run on 64-bit machine.  */
  85 }
  86
  87 int
  88 main (void)
  89 {
  90   fill_r ();
  91   printf ("static uint_fast32_t const crctab[256] =\n{\n  0x00000000");
  92   for (int i = 0; i < 51; i++)
  93     {
  94       printf (",\n  0x%08x, 0x%08x, 0x%08x, 0x%08x, 0x%08x",
  95               crc_remainder (i * 5 + 1), crc_remainder (i * 5 + 2),
  96               crc_remainder (i * 5 + 3), crc_remainder (i * 5 + 4),
  97               crc_remainder (i * 5 + 5));
  98     }
  99   printf ("\n};\n");
 100   return EXIT_SUCCESS;
 101 }
 102
 103 #else /* !CRCTAB */
 104
 105 # include <getopt.h>
 106 # include "long-options.h"
 107 # include "die.h"
 108 # include "error.h"
 109
 110 static struct option const long_options[] =
 111 {
 112   {NULL, 0, NULL, 0}
 113 };
 114
 115 /* Number of bytes to read at once.  */
 116 # define BUFLEN (1 << 16)
 117
 118 static uint_fast32_t const crctab[256] =
 119 {
 120   0x00000000,
 121   0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
 122   0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
 123   0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
 124   0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
 125   0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
 126   0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
 127   0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
 128   0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
 129   0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
 130   0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
 131   0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
 132   0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
 133   0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
 134   0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
 135   0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
 136   0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
 137   0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
 138   0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
 139   0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
 140   0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
 141   0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
 142   0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
 143   0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
 144   0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
 145   0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
 146   0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
 147   0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
 148   0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
 149   0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
 150   0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
 151   0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
 152   0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
 153   0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
 154   0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
 155   0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
 156   0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
 157   0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
 158   0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
 159   0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
 160   0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
 161   0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
 162   0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
 163   0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
 164   0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
 165   0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
 166   0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
 167   0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
 168   0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
 169   0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
 170   0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
 171   0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
 172 };
 173
 174 /* Nonzero if any of the files read were the standard input. */
 175 static bool have_read_stdin;
 176
 177 /* Calculate and print the checksum and length in bytes
 178    of file FILE, or of the standard input if FILE is "-".
 179    If PRINT_NAME is true, print FILE next to the checksum and size.
 180    Return true if successful.  */
 181
 182 static bool
 183 cksum (const char *file, bool print_name)
 184 {
 185   unsigned char buf[BUFLEN];
 186   uint_fast32_t crc = 0;
 187   uintmax_t length = 0;
 188   size_t bytes_read;
 189   FILE *fp;
 190   char length_buf[INT_BUFSIZE_BOUND (uintmax_t)];
 191   char const *hp;
 192
 193   if (STREQ (file, "-"))
 194     {
 195       fp = stdin;
 196       have_read_stdin = true;
 197       xset_binary_mode (STDIN_FILENO, O_BINARY);
 198     }
 199   else
 200     {
 201       fp = fopen (file, (O_BINARY ? "rb" : "r"));
 202       if (fp == NULL)
 203         {
 204           error (0, errno, "%s", quotef (file));
 205           return false;
 206         }
 207     }
 208
 209   fadvise (fp, FADVISE_SEQUENTIAL);
 210
 211   while ((bytes_read = fread (buf, 1, BUFLEN, fp)) > 0)
 212     {
 213       unsigned char *cp = buf;
 214
 215       if (length + bytes_read < length)
 216         die (EXIT_FAILURE, 0, _("%s: file too long"), quotef (file));
 217       length += bytes_read;
 218       while (bytes_read--)
 219         crc = (crc << 8) ^ crctab[((crc >> 24) ^ *cp++) & 0xFF];
 220       if (feof (fp))
 221         break;
 222     }
 223
 224   if (ferror (fp))
 225     {
 226       error (0, errno, "%s", quotef (file));
 227       if (!STREQ (file, "-"))
 228         fclose (fp);
 229       return false;
 230     }
 231
 232   if (!STREQ (file, "-") && fclose (fp) == EOF)
 233     {
 234       error (0, errno, "%s", quotef (file));
 235       return false;
 236     }
 237
 238   hp = umaxtostr (length, length_buf);
 239
 240   for (; length; length >>= 8)
 241     crc = (crc << 8) ^ crctab[((crc >> 24) ^ length) & 0xFF];
 242
 243   crc = ~crc & 0xFFFFFFFF;
 244
 245   if (print_name)
 246     printf ("%u %s %s\n", (unsigned int) crc, hp, file);
 247   else
 248     printf ("%u %s\n", (unsigned int) crc, hp);
 249
 250   if (ferror (stdout))
 251     die (EXIT_FAILURE, errno, "-: %s", _("write error"));
 252
 253   return true;
 254 }
 255
 256 void
 257 usage (int status)
 258 {
 259   if (status != EXIT_SUCCESS)
 260     emit_try_help ();
 261   else
 262     {
 263       printf (_("\
 264 Usage: %s [FILE]...\n\
 265   or:  %s [OPTION]\n\
 266 "),
 267               program_name, program_name);
 268       fputs (_("\
 269 Print CRC checksum and byte counts of each FILE.\n\
 270 \n\
 271 "), stdout);
 272       fputs (HELP_OPTION_DESCRIPTION, stdout);
 273       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 274       emit_ancillary_info (PROGRAM_NAME);
 275     }
 276   exit (status);
 277 }
 278
 279 int
 280 main (int argc, char **argv)
 281 {
 282   int i;
 283   bool ok;
 284
 285   initialize_main (&argc, &argv);
 286   set_program_name (argv[0]);
 287   setlocale (LC_ALL, "");
 288   bindtextdomain (PACKAGE, LOCALEDIR);
 289   textdomain (PACKAGE);
 290
 291   atexit (close_stdout);
 292
 293   /* Line buffer stdout to ensure lines are written atomically and immediately
 294      so that processes running in parallel do not intersperse their output.  */
 295   setvbuf (stdout, NULL, _IOLBF, 0);
 296
 297   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE, Version,
 298                       usage, AUTHORS, (char const *) NULL);
 299   if (getopt_long (argc, argv, "", long_options, NULL) != -1)
 300     usage (EXIT_FAILURE);
 301
 302   have_read_stdin = false;
 303
 304   if (optind == argc)
 305     ok = cksum ("-", false);
 306   else
 307     {
 308       ok = true;
 309       for (i = optind; i < argc; i++)
 310         ok &= cksum (argv[i], true);
 311     }
 312
 313   if (have_read_stdin && fclose (stdin) == EOF)
 314     die (EXIT_FAILURE, errno, "-");
 315   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 316 }
 317
 318 #endif /* !CRCTAB */