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/partition.h>
  26 #include <grub/lib/hexdump.h>
  27 #include <grub/extcmd.h>
  28
  29 static const struct grub_arg_option options[] = {
  30   {"skip", 's', 0, "skip offset bytes from the beginning of file.", 0,
  31    ARG_TYPE_INT},
  32   {"length", 'n', 0, "read only length bytes", 0, ARG_TYPE_INT},
  33   {0, 0, 0, 0, 0, 0}
  34 };
  35
  36 static grub_err_t
  37 grub_cmd_hexdump (grub_extcmd_t cmd, int argc, char **args)
  38 {
  39   struct grub_arg_list *state = cmd->state;
  40   char buf[GRUB_DISK_SECTOR_SIZE * 4];
  41   grub_ssize_t size, length;
  42   grub_addr_t skip;
  43   int namelen;
  44
  45   if (argc != 1)
  46     return grub_error (GRUB_ERR_BAD_ARGUMENT, "file name required");
  47
  48   namelen = grub_strlen (args[0]);
  49   skip = (state[0].set) ? grub_strtoul (state[0].arg, 0, 0) : 0;
  50   length = (state[1].set) ? grub_strtoul (state[1].arg, 0, 0) : 256;
  51
  52   if (!grub_strcmp (args[0], "(mem)"))
  53     hexdump (skip, (char *) skip, length);
  54   else if ((args[0][0] == '(') && (args[0][namelen - 1] == ')'))
  55     {
  56       grub_disk_t disk;
  57       grub_disk_addr_t sector;
  58       grub_size_t ofs;
  59
  60       args[0][namelen - 1] = 0;
  61       disk = grub_disk_open (&args[0][1]);
  62       if (! disk)
  63         return 0;
  64
  65       if (disk->partition)
  66         skip += grub_partition_get_start (disk->partition) << GRUB_DISK_SECTOR_BITS;
  67
  68       sector = (skip >> (GRUB_DISK_SECTOR_BITS + 2)) * 4;
  69       ofs = skip & (GRUB_DISK_SECTOR_SIZE * 4 - 1);
  70       while (length)
  71         {
  72           grub_size_t len, n;
  73
  74           len = length;
  75           if (ofs + len > sizeof (buf))
  76             len = sizeof (buf) - ofs;
  77
  78           n = ((ofs + len + GRUB_DISK_SECTOR_SIZE - 1)
  79                >> GRUB_DISK_SECTOR_BITS);
  80           if (disk->dev->read (disk, sector, n, buf))
  81             break;
  82
  83           hexdump (skip, &buf[ofs], len);
  84
  85           ofs = 0;
  86           skip += len;
  87           length -= len;
  88           sector += 4;
  89         }
  90
  91       grub_disk_close (disk);
  92     }
  93   else
  94     {
  95       grub_file_t file;
  96
  97       file = grub_gzfile_open (args[0], 1);
  98       if (! file)
  99         return 0;
 100
 101       file->offset = skip;
 102
 103       while ((size = grub_file_read (file, buf, sizeof (buf))) > 0)
 104         {
 105           unsigned long len;
 106
 107           len = ((length) && (size > length)) ? length : size;
 108           hexdump (skip, buf, len);
 109           skip += len;
 110           if (length)
 111             {
 112               length -= len;
 113               if (!length)
 114                 break;
 115             }
 116         }
 117
 118       grub_file_close (file);
 119     }
 120
 121   return 0;
 122 }
 123 \f
 124 static grub_extcmd_t cmd;
 125
 126 GRUB_MOD_INIT (hexdump)
 127 {
 128   cmd = grub_register_extcmd ("hexdump", grub_cmd_hexdump,
 129                               GRUB_COMMAND_FLAG_BOTH,
 130                               "hexdump [OPTIONS] FILE_OR_DEVICE",
 131                               "Dump the contents of a file or memory.",
 132                               options);
 133 }
 134
 135 GRUB_MOD_FINI (hexdump)
 136 {
 137   grub_unregister_extcmd (cmd);
 138 }