commands/crc.c

   1 /* crc.c - command to calculate the crc32 checksum of a file  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2008  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/dl.h>
  21 #include <grub/disk.h>
  22 #include <grub/file.h>
  23 #include <grub/misc.h>
  24 #include <grub/lib/crc.h>
  25 #include <grub/command.h>
  26
  27 static grub_err_t
  28 grub_cmd_crc (grub_command_t cmd __attribute__ ((unused)),
  29               int argc, char **args)
  30
  31 {
  32   grub_file_t file;
  33   char buf[GRUB_DISK_SECTOR_SIZE];
  34   grub_ssize_t size;
  35   grub_uint32_t crc;
  36
  37   if (argc != 1)
  38     return grub_error (GRUB_ERR_BAD_ARGUMENT, "file name required");
  39
  40   file = grub_file_open (args[0]);
  41   if (! file)
  42     return 0;
  43
  44   crc = 0;
  45   while ((size = grub_file_read (file, buf, sizeof (buf))) > 0)
  46     crc = grub_getcrc32 (crc, buf, size);
  47
  48   grub_file_close (file);
  49
  50   grub_printf ("%08x\n", crc);
  51
  52   return 0;
  53 }
  54
  55 static grub_command_t cmd;
  56
  57 GRUB_MOD_INIT(crc)
  58 {
  59   cmd = grub_register_command ("crc", grub_cmd_crc,
  60                                "crc FILE",
  61                                "Calculate the crc32 checksum of a file.");
  62 }
  63
  64 GRUB_MOD_FINI(crc)
  65 {
  66   grub_unregister_command (cmd);
  67 }