src/sum.c

   1 /* sum -- checksum and count the blocks in a file
   2    Copyright (C) 1986, 1989, 1991, 1995-2002, 2004-2005, 2008-2010 Free
   3    Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Like BSD sum or SysV sum -r, except like SysV sum if -s option is given. */
  19
  20 /* Written by Kayvan Aghaiepour and David MacKenzie. */
  21
  22 #include <config.h>
  23
  24 #include <stdio.h>
  25 #include <sys/types.h>
  26 #include <getopt.h>
  27 #include "system.h"
  28 #include "error.h"
  29 #include "human.h"
  30 #include "safe-read.h"
  31 #include "xfreopen.h"
  32
  33 /* The official name of this program (e.g., no `g' prefix).  */
  34 #define PROGRAM_NAME "sum"
  35
  36 #define AUTHORS \
  37   proper_name ("Kayvan Aghaiepour"), \
  38   proper_name ("David MacKenzie")
  39
  40 /* True if any of the files read were the standard input. */
  41 static bool have_read_stdin;
  42
  43 static struct option const longopts[] =
  44 {
  45   {"sysv", no_argument, NULL, 's'},
  46   {GETOPT_HELP_OPTION_DECL},
  47   {GETOPT_VERSION_OPTION_DECL},
  48   {NULL, 0, NULL, 0}
  49 };
  50
  51 void
  52 usage (int status)
  53 {
  54   if (status != EXIT_SUCCESS)
  55     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  56              program_name);
  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 \n\
  66   -r              use BSD sum algorithm, use 1K blocks\n\
  67   -s, --sysv      use System V sum algorithm, use 512 bytes blocks\n\
  68 "), stdout);
  69       fputs (HELP_OPTION_DESCRIPTION, stdout);
  70       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  71       fputs (_("\
  72 \n\
  73 With no FILE, or when FILE is -, read standard input.\n\
  74 "), stdout);
  75       emit_ancillary_info ();
  76     }
  77   exit (status);
  78 }
  79
  80 /* Calculate and print the rotated checksum and the size in 1K blocks
  81    of file FILE, or of the standard input if FILE is "-".
  82    If PRINT_NAME is >1, print FILE next to the checksum and size.
  83    The checksum varies depending on sizeof (int).
  84    Return true if successful.  */
  85
  86 static bool
  87 bsd_sum_file (const char *file, int print_name)
  88 {
  89   FILE *fp;
  90   int checksum = 0;     /* The checksum mod 2^16. */
  91   uintmax_t total_bytes = 0;    /* The number of bytes. */
  92   int ch;               /* Each character read. */
  93   char hbuf[LONGEST_HUMAN_READABLE + 1];
  94   bool is_stdin = STREQ (file, "-");
  95
  96   if (is_stdin)
  97     {
  98       fp = stdin;
  99       have_read_stdin = true;
 100       if (O_BINARY && ! isatty (STDIN_FILENO))
 101         xfreopen (NULL, "rb", stdin);
 102     }
 103   else
 104     {
 105       fp = fopen (file, (O_BINARY ? "rb" : "r"));
 106       if (fp == NULL)
 107         {
 108           error (0, errno, "%s", file);
 109           return false;
 110         }
 111     }
 112
 113   while ((ch = getc (fp)) != EOF)
 114     {
 115       total_bytes++;
 116       checksum = (checksum >> 1) + ((checksum & 1) << 15);
 117       checksum += ch;
 118       checksum &= 0xffff;       /* Keep it within bounds. */
 119     }
 120
 121   if (ferror (fp))
 122     {
 123       error (0, errno, "%s", file);
 124       if (!is_stdin)
 125         fclose (fp);
 126       return false;
 127     }
 128
 129   if (!is_stdin && fclose (fp) != 0)
 130     {
 131       error (0, errno, "%s", file);
 132       return false;
 133     }
 134
 135   printf ("%05d %5s", checksum,
 136           human_readable (total_bytes, hbuf, human_ceiling, 1, 1024));
 137   if (print_name > 1)
 138     printf (" %s", file);
 139   putchar ('\n');
 140
 141   return true;
 142 }
 143
 144 /* Calculate and print the checksum and the size in 512-byte blocks
 145    of file FILE, or of the standard input if FILE is "-".
 146    If PRINT_NAME is >0, print FILE next to the checksum and size.
 147    Return true if successful.  */
 148
 149 static bool
 150 sysv_sum_file (const char *file, int print_name)
 151 {
 152   int fd;
 153   unsigned char buf[8192];
 154   uintmax_t total_bytes = 0;
 155   char hbuf[LONGEST_HUMAN_READABLE + 1];
 156   int r;
 157   int checksum;
 158
 159   /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
 160   unsigned int s = 0;
 161
 162   bool is_stdin = STREQ (file, "-");
 163
 164   if (is_stdin)
 165     {
 166       fd = STDIN_FILENO;
 167       have_read_stdin = true;
 168       if (O_BINARY && ! isatty (STDIN_FILENO))
 169         xfreopen (NULL, "rb", stdin);
 170     }
 171   else
 172     {
 173       fd = open (file, O_RDONLY | O_BINARY);
 174       if (fd == -1)
 175         {
 176           error (0, errno, "%s", file);
 177           return false;
 178         }
 179     }
 180
 181   while (1)
 182     {
 183       size_t i;
 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", file);
 192           if (!is_stdin)
 193             close (fd);
 194           return false;
 195         }
 196
 197       for (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", 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     error (EXIT_FAILURE, errno, "-");
 272   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 273 }