src/sum.c

   1 /* sum -- checksum and count the blocks in a file
   2    Copyright (C) 1986-2017 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 /* Like BSD sum or SysV sum -r, except like SysV sum if -s option is given. */
  18
  19 /* Written by Kayvan Aghaiepour and David MacKenzie. */
  20
  21 #include <config.h>
  22
  23 #include <stdio.h>
  24 #include <sys/types.h>
  25 #include <getopt.h>
  26 #include "system.h"
  27 #include "die.h"
  28 #include "error.h"
  29 #include "fadvise.h"
  30 #include "human.h"
  31 #include "safe-read.h"
  32 #include "xfreopen.h"
  33
  34 /* The official name of this program (e.g., no 'g' prefix).  */
  35 #define PROGRAM_NAME "sum"
  36
  37 #define AUTHORS \
  38   proper_name ("Kayvan Aghaiepour"), \
  39   proper_name ("David MacKenzie")
  40
  41 /* True if any of the files read were the standard input. */
  42 static bool have_read_stdin;
  43
  44 static struct option const longopts[] =
  45 {
  46   {"sysv", no_argument, NULL, 's'},
  47   {GETOPT_HELP_OPTION_DECL},
  48   {GETOPT_VERSION_OPTION_DECL},
  49   {NULL, 0, NULL, 0}
  50 };
  51
  52 void
  53 usage (int status)
  54 {
  55   if (status != EXIT_SUCCESS)
  56     emit_try_help ();
  57   else
  58     {
  59       printf (_("\
  60 Usage: %s [OPTION]... [FILE]...\n\
  61 "),
  62               program_name);
  63       fputs (_("\
  64 Print checksum and block counts for each FILE.\n\
  65 "), stdout);
  66
  67       emit_stdin_note ();
  68
  69       fputs (_("\
  70 \n\
  71   -r              use BSD sum algorithm, use 1K blocks\n\
  72   -s, --sysv      use System V sum algorithm, use 512 bytes blocks\n\
  73 "), stdout);
  74       fputs (HELP_OPTION_DESCRIPTION, stdout);
  75       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  76       emit_ancillary_info (PROGRAM_NAME);
  77     }
  78   exit (status);
  79 }
  80
  81 /* Calculate and print the rotated checksum and the size in 1K blocks
  82    of file FILE, or of the standard input if FILE is "-".
  83    If PRINT_NAME is >1, print FILE next to the checksum and size.
  84    The checksum varies depending on sizeof (int).
  85    Return true if successful.  */
  86
  87 static bool
  88 bsd_sum_file (const char *file, int print_name)
  89 {
  90   FILE *fp;
  91   int checksum = 0;     /* The checksum mod 2^16. */
  92   uintmax_t total_bytes = 0;    /* The number of bytes. */
  93   int ch;               /* Each character read. */
  94   char hbuf[LONGEST_HUMAN_READABLE + 1];
  95   bool is_stdin = STREQ (file, "-");
  96
  97   if (is_stdin)
  98     {
  99       fp = stdin;
 100       have_read_stdin = true;
 101       if (O_BINARY && ! isatty (STDIN_FILENO))
 102         xfreopen (NULL, "rb", stdin);
 103     }
 104   else
 105     {
 106       fp = fopen (file, (O_BINARY ? "rb" : "r"));
 107       if (fp == NULL)
 108         {
 109           error (0, errno, "%s", quotef (file));
 110           return false;
 111         }
 112     }
 113
 114   fadvise (fp, FADVISE_SEQUENTIAL);
 115
 116   while ((ch = getc (fp)) != EOF)
 117     {
 118       total_bytes++;
 119       checksum = (checksum >> 1) + ((checksum & 1) << 15);
 120       checksum += ch;
 121       checksum &= 0xffff;       /* Keep it within bounds. */
 122     }
 123
 124   if (ferror (fp))
 125     {
 126       error (0, errno, "%s", quotef (file));
 127       if (!is_stdin)
 128         fclose (fp);
 129       return false;
 130     }
 131
 132   if (!is_stdin && fclose (fp) != 0)
 133     {
 134       error (0, errno, "%s", quotef (file));
 135       return false;
 136     }
 137
 138   printf ("%05d %5s", checksum,
 139           human_readable (total_bytes, hbuf, human_ceiling, 1, 1024));
 140   if (print_name > 1)
 141     printf (" %s", file);
 142   putchar ('\n');
 143
 144   return true;
 145 }
 146
 147 /* Calculate and print the checksum and the size in 512-byte blocks
 148    of file FILE, or of the standard input if FILE is "-".
 149    If PRINT_NAME is >0, print FILE next to the checksum and size.
 150    Return true if successful.  */
 151
 152 static bool
 153 sysv_sum_file (const char *file, int print_name)
 154 {
 155   int fd;
 156   unsigned char buf[8192];
 157   uintmax_t total_bytes = 0;
 158   char hbuf[LONGEST_HUMAN_READABLE + 1];
 159   int r;
 160   int checksum;
 161
 162   /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
 163   unsigned int s = 0;
 164
 165   bool is_stdin = STREQ (file, "-");
 166
 167   if (is_stdin)
 168     {
 169       fd = STDIN_FILENO;
 170       have_read_stdin = true;
 171       if (O_BINARY && ! isatty (STDIN_FILENO))
 172         xfreopen (NULL, "rb", stdin);
 173     }
 174   else
 175     {
 176       fd = open (file, O_RDONLY | O_BINARY);
 177       if (fd == -1)
 178         {
 179           error (0, errno, "%s", quotef (file));
 180           return false;
 181         }
 182     }
 183
 184   while (1)
 185     {
 186       size_t i;
 187       size_t bytes_read = safe_read (fd, buf, sizeof buf);
 188
 189       if (bytes_read == 0)
 190         break;
 191
 192       if (bytes_read == SAFE_READ_ERROR)
 193         {
 194           error (0, errno, "%s", quotef (file));
 195           if (!is_stdin)
 196             close (fd);
 197           return false;
 198         }
 199
 200       for (i = 0; i < bytes_read; i++)
 201         s += buf[i];
 202       total_bytes += bytes_read;
 203     }
 204
 205   if (!is_stdin && close (fd) != 0)
 206     {
 207       error (0, errno, "%s", quotef (file));
 208       return false;
 209     }
 210
 211   r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
 212   checksum = (r & 0xffff) + (r >> 16);
 213
 214   printf ("%d %s", checksum,
 215           human_readable (total_bytes, hbuf, human_ceiling, 1, 512));
 216   if (print_name)
 217     printf (" %s", file);
 218   putchar ('\n');
 219
 220   return true;
 221 }
 222
 223 int
 224 main (int argc, char **argv)
 225 {
 226   bool ok;
 227   int optc;
 228   int files_given;
 229   bool (*sum_func) (const char *, int) = bsd_sum_file;
 230
 231   initialize_main (&argc, &argv);
 232   set_program_name (argv[0]);
 233   setlocale (LC_ALL, "");
 234   bindtextdomain (PACKAGE, LOCALEDIR);
 235   textdomain (PACKAGE);
 236
 237   atexit (close_stdout);
 238
 239   /* Line buffer stdout to ensure lines are written atomically and immediately
 240      so that processes running in parallel do not intersperse their output.  */
 241   setvbuf (stdout, NULL, _IOLBF, 0);
 242
 243   have_read_stdin = false;
 244
 245   while ((optc = getopt_long (argc, argv, "rs", longopts, NULL)) != -1)
 246     {
 247       switch (optc)
 248         {
 249         case 'r':               /* For SysV compatibility. */
 250           sum_func = bsd_sum_file;
 251           break;
 252
 253         case 's':
 254           sum_func = sysv_sum_file;
 255           break;
 256
 257         case_GETOPT_HELP_CHAR;
 258
 259         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 260
 261         default:
 262           usage (EXIT_FAILURE);
 263         }
 264     }
 265
 266   files_given = argc - optind;
 267   if (files_given <= 0)
 268     ok = sum_func ("-", files_given);
 269   else
 270     for (ok = true; optind < argc; optind++)
 271       ok &= sum_func (argv[optind], files_given);
 272
 273   if (have_read_stdin && fclose (stdin) == EOF)
 274     die (EXIT_FAILURE, errno, "%s", quotef ("-"));
 275   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 276 }