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