grub-core/commands/hexdump.c

   1 /* hexdump.c - command to dump the contents of a file or memory */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2007,2008,2009  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/file.h>
  22 #include <grub/disk.h>
  23 #include <grub/misc.h>
  24 #include <grub/lib/hexdump.h>
  25 #include <grub/extcmd.h>
  26 #include <grub/i18n.h>
  27
  28 GRUB_MOD_LICENSE ("GPLv3+");
  29
  30 static const struct grub_arg_option options[] = {
  31   {"skip", 's', 0, N_("Skip offset bytes from the beginning of file."), 0,
  32    ARG_TYPE_INT},
  33   {"length", 'n', 0, N_("Read only LENGTH bytes."), 0, ARG_TYPE_INT},
  34   {0, 0, 0, 0, 0, 0}
  35 };
  36
  37 static grub_err_t
  38 grub_cmd_hexdump (grub_extcmd_context_t ctxt, int argc, char **args)
  39 {
  40   struct grub_arg_list *state = ctxt->state;
  41   char buf[GRUB_DISK_SECTOR_SIZE * 4];
  42   grub_ssize_t size, length;
  43   grub_disk_addr_t skip;
  44   int namelen;
  45
  46   if (argc != 1)
  47     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
  48
  49   namelen = grub_strlen (args[0]);
  50   skip = (state[0].set) ? grub_strtoull (state[0].arg, 0, 0) : 0;
  51   length = (state[1].set) ? grub_strtoul (state[1].arg, 0, 0) : 256;
  52
  53   if (!grub_strcmp (args[0], "(mem)"))
  54     hexdump (skip, (char *) (grub_addr_t) skip, length);
  55   else if ((args[0][0] == '(') && (args[0][namelen - 1] == ')'))
  56     {
  57       grub_disk_t disk;
  58       grub_disk_addr_t sector;
  59       grub_size_t ofs;
  60
  61       args[0][namelen - 1] = 0;
  62       disk = grub_disk_open (&args[0][1]);
  63       if (! disk)
  64         return 0;
  65
  66       sector = (skip >> (GRUB_DISK_SECTOR_BITS + 2)) * 4;
  67       ofs = skip & (GRUB_DISK_SECTOR_SIZE * 4 - 1);
  68       while (length)
  69         {
  70           grub_size_t len;
  71
  72           len = length;
  73           if (len > sizeof (buf))
  74             len = sizeof (buf);
  75
  76           if (grub_disk_read (disk, sector, ofs, len, buf))
  77             break;
  78
  79           hexdump (skip, buf, len);
  80
  81           ofs = 0;
  82           skip += len;
  83           length -= len;
  84           sector += 4;
  85         }
  86
  87       grub_disk_close (disk);
  88     }
  89   else
  90     {
  91       grub_file_t file;
  92
  93       file = grub_file_open (args[0], GRUB_FILE_TYPE_HEXCAT);
  94       if (! file)
  95         return 0;
  96
  97       file->offset = skip;
  98
  99       while ((size = grub_file_read (file, buf, sizeof (buf))) > 0)
 100         {
 101           unsigned long len;
 102
 103           len = ((length) && (size > length)) ? length : size;
 104           hexdump (skip, buf, len);
 105           skip += len;
 106           if (length)
 107             {
 108               length -= len;
 109               if (!length)
 110                 break;
 111             }
 112         }
 113
 114       grub_file_close (file);
 115     }
 116
 117   return 0;
 118 }
 119 \f
 120 static grub_extcmd_t cmd;
 121
 122 GRUB_MOD_INIT (hexdump)
 123 {
 124   cmd = grub_register_extcmd ("hexdump", grub_cmd_hexdump, 0,
 125                               N_("[OPTIONS] FILE_OR_DEVICE"),
 126                               N_("Show raw contents of a file or memory."),
 127                               options);
 128 }
 129
 130 GRUB_MOD_FINI (hexdump)
 131 {
 132   grub_unregister_extcmd (cmd);
 133 }