src/sum.c

   1 /* sum -- checksum and count the blocks in a file
   2    Copyright (C) 1986-2013 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 "error.h"
  28 #include "fadvise.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     emit_try_help ();
  56   else
  57     {
  58       printf (_("\
  59 Usage: %s [OPTION]... [FILE]...\n\
  60 "),
  61               program_name);
  62       fputs (_("\
  63 Print checksum and block counts for each FILE.\n\
  64 \n\
  65   -r              use BSD sum algorithm, use 1K blocks\n\
  66   -s, --sysv      use System V sum algorithm, use 512 bytes blocks\n\
  67 "), stdout);
  68       fputs (HELP_OPTION_DESCRIPTION, stdout);
  69       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  70       fputs (_("\
  71 \n\
  72 With no FILE, or when FILE is -, read standard input.\n\
  73 "), stdout);
  74       emit_ancillary_info ();
  75     }
  76   exit (status);
  77 }
  78
  79 /* Calculate and print the rotated checksum and the size in 1K blocks
  80    of file FILE, or of the standard input if FILE is "-".
  81    If PRINT_NAME is >1, print FILE next to the checksum and size.
  82    The checksum varies depending on sizeof (int).
  83    Return true if successful.  */
  84
  85 static bool
  86 bsd_sum_file (const char *file, int print_name)
  87 {
  88   FILE *fp;
  89   int checksum = 0;     /* The checksum mod 2^16. */
  90   uintmax_t total_bytes = 0;    /* The number of bytes. */
  91   int ch;               /* Each character read. */
  92   char hbuf[LONGEST_HUMAN_READABLE + 1];
  93   bool is_stdin = STREQ (file, "-");
  94
  95   if (is_stdin)
  96     {
  97       fp = stdin;
  98       have_read_stdin = true;
  99       if (O_BINARY && ! isatty (STDIN_FILENO))
 100         xfreopen (NULL, "rb", stdin);
 101     }
 102   else
 103     {
 104       fp = fopen (file, (O_BINARY ? "rb" : "r"));
 105       if (fp == NULL)
 106         {
 107           error (0, errno, "%s", file);
 108           return false;
 109         }
 110     }
 111
 112   fadvise (fp, FADVISE_SEQUENTIAL);
 113
 114   while ((ch = getc (fp)) != EOF)
 115     {
 116       total_bytes++;
 117       checksum = (checksum >> 1) + ((checksum & 1) << 15);
 118       checksum += ch;
 119       checksum &= 0xffff;       /* Keep it within bounds. */
 120     }
 121
 122   if (ferror (fp))
 123     {
 124       error (0, errno, "%s", file);
 125       if (!is_stdin)
 126         fclose (fp);
 127       return false;
 128     }
 129
 130   if (!is_stdin && fclose (fp) != 0)
 131     {
 132       error (0, errno, "%s", file);
 133       return false;
 134     }
 135
 136   printf ("%05d %5s", checksum,
 137           human_readable (total_bytes, hbuf, human_ceiling, 1, 1024));
 138   if (print_name > 1)
 139     printf (" %s", file);
 140   putchar ('\n');
 141
 142   return true;
 143 }
 144
 145 /* Calculate and print the checksum and the size in 512-byte blocks
 146    of file FILE, or of the standard input if FILE is "-".
 147    If PRINT_NAME is >0, print FILE next to the checksum and size.
 148    Return true if successful.  */
 149
 150 static bool
 151 sysv_sum_file (const char *file, int print_name)
 152 {
 153   int fd;
 154   unsigned char buf[8192];
 155   uintmax_t total_bytes = 0;
 156   char hbuf[LONGEST_HUMAN_READABLE + 1];
 157   int r;
 158   int checksum;
 159
 160   /* The sum of all the input bytes, modulo (UINT_MAX + 1).  */
 161   unsigned int s = 0;
 162
 163   bool is_stdin = STREQ (file, "-");
 164
 165   if (is_stdin)
 166     {
 167       fd = STDIN_FILENO;
 168       have_read_stdin = true;
 169       if (O_BINARY && ! isatty (STDIN_FILENO))
 170         xfreopen (NULL, "rb", stdin);
 171     }
 172   else
 173     {
 174       fd = open (file, O_RDONLY | O_BINARY);
 175       if (fd == -1)
 176         {
 177           error (0, errno, "%s", file);
 178           return false;
 179         }
 180     }
 181
 182   while (1)
 183     {
 184       size_t i;
 185       size_t bytes_read = safe_read (fd, buf, sizeof buf);
 186
 187       if (bytes_read == 0)
 188         break;
 189
 190       if (bytes_read == SAFE_READ_ERROR)
 191         {
 192           error (0, errno, "%s", file);
 193           if (!is_stdin)
 194             close (fd);
 195           return false;
 196         }
 197
 198       for (i = 0; i < bytes_read; i++)
 199         s += buf[i];
 200       total_bytes += bytes_read;
 201     }
 202
 203   if (!is_stdin && close (fd) != 0)
 204     {
 205       error (0, errno, "%s", file);
 206       return false;
 207     }
 208
 209   r = (s & 0xffff) + ((s & 0xffffffff) >> 16);
 210   checksum = (r & 0xffff) + (r >> 16);
 211
 212   printf ("%d %s", checksum,
 213           human_readable (total_bytes, hbuf, human_ceiling, 1, 512));
 214   if (print_name)
 215     printf (" %s", file);
 216   putchar ('\n');
 217
 218   return true;
 219 }
 220
 221 int
 222 main (int argc, char **argv)
 223 {
 224   bool ok;
 225   int optc;
 226   int files_given;
 227   bool (*sum_func) (const char *, int) = bsd_sum_file;
 228
 229   initialize_main (&argc, &argv);
 230   set_program_name (argv[0]);
 231   setlocale (LC_ALL, "");
 232   bindtextdomain (PACKAGE, LOCALEDIR);
 233   textdomain (PACKAGE);
 234
 235   atexit (close_stdout);
 236
 237   /* Line buffer stdout to ensure lines are written atomically and immediately
 238      so that processes running in parallel do not intersperse their output.  */
 239   setvbuf (stdout, NULL, _IOLBF, 0);
 240
 241   have_read_stdin = false;
 242
 243   while ((optc = getopt_long (argc, argv, "rs", longopts, NULL)) != -1)
 244     {
 245       switch (optc)
 246         {
 247         case 'r':               /* For SysV compatibility. */
 248           sum_func = bsd_sum_file;
 249           break;
 250
 251         case 's':
 252           sum_func = sysv_sum_file;
 253           break;
 254
 255         case_GETOPT_HELP_CHAR;
 256
 257         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 258
 259         default:
 260           usage (EXIT_FAILURE);
 261         }
 262     }
 263
 264   files_given = argc - optind;
 265   if (files_given <= 0)
 266     ok = sum_func ("-", files_given);
 267   else
 268     for (ok = true; optind < argc; optind++)
 269       ok &= sum_func (argv[optind], files_given);
 270
 271   if (have_read_stdin && fclose (stdin) == EOF)
 272     error (EXIT_FAILURE, errno, "-");
 273   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 274 }