src/sum.c

   1 /* sum -- checksum and count the blocks in a file
   2    Copyright (C) 1986-2019 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 /* 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 "xbinary-io.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       xset_binary_mode (STDIN_FILENO, O_BINARY);
 102     }
 103   else
 104     {
 105       fp = fopen (file, (O_BINARY ? "rb" : "r"));
 106       if (fp == NULL)
 107         {
 108           error (0, errno, "%s", quotef (file));
 109           return false;
 110         }
 111     }
 112
 113   fadvise (fp, FADVISE_SEQUENTIAL);
 114
 115   while ((ch = getc (fp)) != EOF)
 116     {
 117       total_bytes++;
 118       checksum = (checksum >> 1) + ((checksum & 1) << 15);
 119       checksum += ch;
 120       checksum &= 0xffff;       /* Keep it within bounds. */
 121     }
 122
 123   if (ferror (fp))
 124     {
 125       error (0, errno, "%s", quotef (file));
 126       if (!is_stdin)
 127         fclose (fp);
 128       return false;
 129     }
 130
 131   if (!is_stdin && fclose (fp) != 0)
 132     {
 133       error (0, errno, "%s", quotef (file));
 134       return false;
 135     }
 136
 137   printf ("%05d %5s", checksum,
 138           human_readable (total_bytes, hbuf, human_ceiling, 1, 1024));
 139   if (print_name > 1)
 140     printf (" %s", file);
 141   putchar ('\n');
 142
 143   return true;
 144 }
 145
 146 /* Calculate and print the checksum and the size in 512-byte blocks
 147    of file FILE, or of the standard input if FILE is "-".
 148    If PRINT_NAME is >0, print FILE next to the checksum and size.
 149    Return true if successful.  */
 150
 151 static bool
 152 sysv_sum_file (const char *file, int print_name)
 153 {
 154   int fd;
 155   unsigned char buf[8192];
 156   uintmax_t total_bytes = 0;
 157   char hbuf[LONGEST_HUMAN_READABLE + 1];
 158   int r;
 159   int checksum;
 160
 161   /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
 162   unsigned int s = 0;
 163
 164   bool is_stdin = STREQ (file, "-");
 165
 166   if (is_stdin)
 167     {
 168       fd = STDIN_FILENO;
 169       have_read_stdin = true;
 170       xset_binary_mode (STDIN_FILENO, O_BINARY);
 171     }
 172   else
 173     {
 174       fd = open (file, O_RDONLY | O_BINARY);
 175       if (fd == -1)
 176         {
 177           error (0, errno, "%s", quotef (file));
 178           return false;
 179         }
 180     }
 181
 182   while (1)
 183     {
 184       size_t bytes_read = safe_read (fd, buf, sizeof buf);
 185
 186       if (bytes_read == 0)
 187         break;
 188
 189       if (bytes_read == SAFE_READ_ERROR)
 190         {
 191           error (0, errno, "%s", quotef (file));
 192           if (!is_stdin)
 193             close (fd);
 194           return false;
 195         }
 196
 197       for (size_t i = 0; i < bytes_read; i++)
 198         s += buf[i];
 199       total_bytes += bytes_read;
 200     }
 201
 202   if (!is_stdin && close (fd) != 0)
 203     {
 204       error (0, errno, "%s", quotef (file));
 205       return false;
 206     }
 207
 208   r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
 209   checksum = (r & 0xffff) + (r >> 16);
 210
 211   printf ("%d %s", checksum,
 212           human_readable (total_bytes, hbuf, human_ceiling, 1, 512));
 213   if (print_name)
 214     printf (" %s", file);
 215   putchar ('\n');
 216
 217   return true;
 218 }
 219
 220 int
 221 main (int argc, char **argv)
 222 {
 223   bool ok;
 224   int optc;
 225   int files_given;
 226   bool (*sum_func) (const char *, int) = bsd_sum_file;
 227
 228   initialize_main (&argc, &argv);
 229   set_program_name (argv[0]);
 230   setlocale (LC_ALL, "");
 231   bindtextdomain (PACKAGE, LOCALEDIR);
 232   textdomain (PACKAGE);
 233
 234   atexit (close_stdout);
 235
 236   /* Line buffer stdout to ensure lines are written atomically and immediately
 237      so that processes running in parallel do not intersperse their output.  */
 238   setvbuf (stdout, NULL, _IOLBF, 0);
 239
 240   have_read_stdin = false;
 241
 242   while ((optc = getopt_long (argc, argv, "rs", longopts, NULL)) != -1)
 243     {
 244       switch (optc)
 245         {
 246         case 'r':               /* For SysV compatibility. */
 247           sum_func = bsd_sum_file;
 248           break;
 249
 250         case 's':
 251           sum_func = sysv_sum_file;
 252           break;
 253
 254         case_GETOPT_HELP_CHAR;
 255
 256         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 257
 258         default:
 259           usage (EXIT_FAILURE);
 260         }
 261     }
 262
 263   files_given = argc - optind;
 264   if (files_given <= 0)
 265     ok = sum_func ("-", files_given);
 266   else
 267     for (ok = true; optind < argc; optind++)
 268       ok &= sum_func (argv[optind], files_given);
 269
 270   if (have_read_stdin && fclose (stdin) == EOF)
 271     die (EXIT_FAILURE, errno, "%s", quotef ("-"));
 272   return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 273 }