commands/cmp.c

   1 /* cmd.c - command to cmp an operating system */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2003,2005,2006,2007  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/misc.h>
  22 #include <grub/file.h>
  23 #include <grub/mm.h>
  24 #include <grub/gzio.h>
  25 #include <grub/command.h>
  26
  27 #define BUFFER_SIZE 512
  28
  29 static grub_err_t
  30 grub_cmd_cmp (grub_command_t cmd __attribute__ ((unused)),
  31               int argc, char **args)
  32 {
  33   grub_ssize_t rd1, rd2;
  34   grub_off_t pos;
  35   grub_file_t file1 = 0;
  36   grub_file_t file2 = 0;
  37   char *buf1 = 0;
  38   char *buf2 = 0;
  39
  40   if (argc != 2)
  41     return grub_error (GRUB_ERR_BAD_ARGUMENT, "two arguments required");
  42
  43   grub_printf ("Compare `%s' and `%s':\n", args[0],
  44                args[1]);
  45
  46   file1 = grub_gzfile_open (args[0], 1);
  47   file2 = grub_gzfile_open (args[1], 1);
  48   if (! file1 || ! file2)
  49     goto cleanup;
  50
  51   if (grub_file_size (file1) != grub_file_size (file2))
  52     grub_printf ("Differ in size: %llu [%s], %llu [%s]\n",
  53                  (unsigned long long) grub_file_size (file1), args[0],
  54                  (unsigned long long) grub_file_size (file2), args[1]);
  55   else
  56     {
  57       pos = 0;
  58
  59       buf1 = grub_malloc (BUFFER_SIZE);
  60       buf2 = grub_malloc (BUFFER_SIZE);
  61
  62       if (! buf1 || ! buf2)
  63         goto cleanup;
  64
  65       do
  66         {
  67           int i;
  68
  69           rd1 = grub_file_read (file1, buf1, BUFFER_SIZE);
  70           rd2 = grub_file_read (file2, buf2, BUFFER_SIZE);
  71
  72           if (rd1 != rd2)
  73             goto cleanup;
  74
  75           for (i = 0; i < rd2; i++)
  76             {
  77               if (buf1[i] != buf2[i])
  78                 {
  79                   grub_printf ("Differ at the offset %llu: 0x%x [%s], 0x%x [%s]\n",
  80                                (unsigned long long) (i + pos), buf1[i], args[0],
  81                                buf2[i], args[1]);
  82                   goto cleanup;
  83                 }
  84             }
  85           pos += BUFFER_SIZE;
  86
  87         }
  88       while (rd2);
  89
  90       grub_printf ("The files are identical.\n");
  91     }
  92
  93 cleanup:
  94
  95   if (buf1)
  96     grub_free (buf1);
  97   if (buf2)
  98     grub_free (buf2);
  99   if (file1)
 100     grub_file_close (file1);
 101   if (file2)
 102     grub_file_close (file2);
 103
 104   return grub_errno;
 105 }
 106
 107 static grub_command_t cmd;
 108 \f
 109 GRUB_MOD_INIT(cmp)
 110 {
 111   cmd = grub_register_command ("cmp", grub_cmd_cmp,
 112                                "cmp FILE1 FILE2", "Compare two files.");
 113 }
 114
 115 GRUB_MOD_FINI(cmp)
 116 {
 117   grub_unregister_command (cmd);
 118 }