commands/memrw.c

   1 /* memrw.c - command to read / write physical memory  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2009  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/command.h>
  23
  24 static grub_command_t cmd_read_byte, cmd_read_word, cmd_read_dword;
  25 static grub_command_t cmd_write_byte, cmd_write_word, cmd_write_dword;
  26
  27 static grub_err_t
  28 grub_cmd_read (grub_command_t cmd, int argc, char **argv)
  29 {
  30   grub_target_addr_t addr;
  31   grub_uint32_t value;
  32
  33   if (argc != 1)
  34     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Invalid number of arguments");
  35
  36   addr = grub_strtoul (argv[0], 0, 0);
  37   if (cmd->name[5] == 'd')
  38     value = *((grub_uint32_t *) addr);
  39   else if (cmd->name[5] == 'w')
  40     value = *((grub_uint16_t *) addr);
  41   else
  42     value = *((grub_uint8_t *) addr);
  43
  44   grub_printf ("0x%x\n", value);
  45
  46   return 0;
  47 }
  48
  49 static grub_err_t
  50 grub_cmd_write (grub_command_t cmd, int argc, char **argv)
  51 {
  52   grub_target_addr_t addr;
  53   grub_uint32_t value;
  54
  55   if (argc != 2)
  56     return grub_error (GRUB_ERR_BAD_ARGUMENT, "Invalid number of arguments");
  57
  58   addr = grub_strtoul (argv[0], 0, 0);
  59   value = grub_strtoul (argv[1], 0, 0);
  60   if (cmd->name[6] == 'd')
  61     *((grub_uint32_t *) addr) = value;
  62   else if (cmd->name[6] == 'w')
  63     *((grub_uint16_t *) addr) = (grub_uint16_t) value;
  64   else
  65     *((grub_uint8_t *) addr) = (grub_uint8_t) value;
  66
  67   return 0;
  68 }
  69
  70 GRUB_MOD_INIT(memrw)
  71 {
  72   cmd_read_byte =
  73     grub_register_command ("read_byte", grub_cmd_read,
  74                            "read_byte ADDR", "Read byte from ADDR.");
  75   cmd_read_word =
  76     grub_register_command ("read_word", grub_cmd_read,
  77                            "read_word ADDR", "Read word from ADDR.");
  78   cmd_read_dword =
  79     grub_register_command ("read_dword", grub_cmd_read,
  80                            "read_dword ADDR", "Read dword from ADDR.");
  81   cmd_write_byte =
  82     grub_register_command ("write_byte", grub_cmd_write,
  83                            "write_byte ADDR VALUE", "Write byte VALUE to ADDR.");
  84   cmd_write_word =
  85     grub_register_command ("write_word", grub_cmd_write,
  86                            "write_word ADDR VALUE", "Write word VALUE to ADDR.");
  87   cmd_write_dword =
  88     grub_register_command ("write_dword", grub_cmd_write,
  89                            "write_dword ADDR VALUE", "Write dword VALUE to ADDR.");
  90 }
  91
  92 GRUB_MOD_FINI(memrw)
  93 {
  94   grub_unregister_command (cmd_read_byte);
  95   grub_unregister_command (cmd_read_word);
  96   grub_unregister_command (cmd_read_dword);
  97   grub_unregister_command (cmd_write_byte);
  98   grub_unregister_command (cmd_write_word);
  99   grub_unregister_command (cmd_write_dword);
 100 }