arch/common/boot/grub2/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/normal.h>
  21 #include <grub/dl.h>
  22 #include <grub/arg.h>
  23 #include <grub/misc.h>
  24 #include <grub/file.h>
  25 #include <grub/mm.h>
  26 #include <grub/gzio.h>
  27
  28 #define BUFFER_SIZE 512
  29
  30 static grub_err_t
  31 grub_cmd_cmp (struct grub_arg_list *state __attribute__ ((unused)),
  32               int argc, char **args)
  33 {
  34   grub_ssize_t rd1, rd2;
  35   grub_off_t pos;
  36   grub_file_t file1 = 0;
  37   grub_file_t file2 = 0;
  38   char *buf1 = 0;
  39   char *buf2 = 0;
  40
  41   if (argc != 2)
  42     return grub_error (GRUB_ERR_BAD_ARGUMENT, "two arguments required");
  43
  44   grub_printf ("Compare `%s' and `%s':\n", args[0],
  45                args[1]);
  46
  47   file1 = grub_gzfile_open (args[0], 1);
  48   file2 = grub_gzfile_open (args[1], 1);
  49   if (! file1 || ! file2)
  50     goto cleanup;
  51
  52   if (grub_file_size (file1) != grub_file_size (file2))
  53     grub_printf ("Differ in size: %llu [%s], %llu [%s]\n",
  54                  (unsigned long long) grub_file_size (file1), args[0],
  55                  (unsigned long long) grub_file_size (file2), args[1]);
  56   else
  57     {
  58       pos = 0;
  59
  60       buf1 = grub_malloc (BUFFER_SIZE);
  61       buf2 = grub_malloc (BUFFER_SIZE);
  62
  63       if (! buf1 || ! buf2)
  64         goto cleanup;
  65
  66       do
  67         {
  68           int i;
  69
  70           rd1 = grub_file_read (file1, buf1, BUFFER_SIZE);
  71           rd2 = grub_file_read (file2, buf2, BUFFER_SIZE);
  72
  73           if (rd1 != rd2)
  74             goto cleanup;
  75
  76           for (i = 0; i < rd2; i++)
  77             {
  78               if (buf1[i] != buf2[i])
  79                 {
  80                   grub_printf ("Differ at the offset %llu: 0x%x [%s], 0x%x [%s]\n",
  81                                (unsigned long long) (i + pos), buf1[i], args[0],
  82                                buf2[i], args[1]);
  83                   goto cleanup;
  84                 }
  85             }
  86           pos += BUFFER_SIZE;
  87
  88         }
  89       while (rd2);
  90
  91       grub_printf ("The files are identical.\n");
  92     }
  93
  94 cleanup:
  95
  96   if (buf1)
  97     grub_free (buf1);
  98   if (buf2)
  99     grub_free (buf2);
 100   if (file1)
 101     grub_file_close (file1);
 102   if (file2)
 103     grub_file_close (file2);
 104
 105   return grub_errno;
 106 }
 107
 108 \f
 109 GRUB_MOD_INIT(cmp)
 110 {
 111   (void) mod;                   /* To stop warning. */
 112   grub_register_command ("cmp", grub_cmd_cmp, GRUB_COMMAND_FLAG_BOTH,
 113                          "cmp FILE1 FILE2", "Compare two files.", 0);
 114 }
 115
 116 GRUB_MOD_FINI(cmp)
 117 {
 118   grub_unregister_command ("cmp");
 119 }