arch/common/boot/grub2/commands/loadenv.c

   1 /* loadenv.c - command to load/save environment variable.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 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/normal.h>
  21 #include <grub/dl.h>
  22 #include <grub/mm.h>
  23 #include <grub/arg.h>
  24 #include <grub/file.h>
  25 #include <grub/disk.h>
  26 #include <grub/misc.h>
  27 #include <grub/env.h>
  28 #include <grub/partition.h>
  29 #include <grub/lib/envblk.h>
  30
  31 static const struct grub_arg_option options[] =
  32   {
  33     {"file", 'f', 0, "specify filename", 0, ARG_TYPE_PATHNAME},
  34     {0, 0, 0, 0, 0, 0}
  35   };
  36
  37 char buffer[GRUB_ENVBLK_MAXLEN];
  38 grub_envblk_t envblk;
  39
  40 static grub_file_t
  41 read_envblk_file (char *filename, void NESTED_FUNC_ATTR read_hook (grub_disk_addr_t sector, unsigned offset, unsigned length))
  42 {
  43   char *buf = 0;
  44   grub_file_t file;
  45
  46   if (! filename)
  47     {
  48       char *prefix;
  49
  50       prefix = grub_env_get ("prefix");
  51       if (prefix)
  52         {
  53           int len;
  54
  55           len = grub_strlen (prefix);
  56           buf = grub_malloc (len + 1 + sizeof (GRUB_ENVBLK_DEFCFG));
  57           grub_strcpy (buf, prefix);
  58           buf[len] = '/';
  59           grub_strcpy (buf + len + 1, GRUB_ENVBLK_DEFCFG);
  60           filename = buf;
  61         }
  62       else
  63         {
  64           grub_error (GRUB_ERR_FILE_NOT_FOUND, "prefix is not found");
  65           return 0;
  66         }
  67     }
  68
  69   file = grub_file_open (filename);
  70   grub_free (buf);
  71   if (! file)
  72     return 0;
  73
  74   if (read_hook)
  75     {
  76       if (! file->device->disk)
  77         {
  78           grub_file_close (file);
  79           grub_error (GRUB_ERR_BAD_DEVICE,
  80                       "this command is available only for disk devices.");
  81           return 0;
  82         }
  83       file->read_hook = read_hook;
  84     }
  85
  86   if (grub_file_read (file, buffer, GRUB_ENVBLK_MAXLEN) != GRUB_ENVBLK_MAXLEN)
  87     {
  88       grub_file_close (file);
  89       grub_error (GRUB_ERR_BAD_FILE_TYPE, "file too short");
  90       return 0;
  91     }
  92
  93   envblk = grub_envblk_find (buffer);
  94   if (! envblk)
  95     {
  96       grub_file_close (file);
  97       grub_error (GRUB_ERR_BAD_FILE_TYPE, "environment block not found");
  98       return 0;
  99     }
 100
 101   return file;
 102 }
 103
 104 static grub_err_t
 105 grub_cmd_load_env (struct grub_arg_list *state,
 106                    int argc __attribute__ ((unused)), char **args __attribute__ ((unused)))
 107
 108 {
 109   grub_file_t file;
 110
 111   auto int hook (char *name, char *value);
 112   int hook (char *name, char *value)
 113     {
 114       grub_env_set (name, value);
 115
 116       return 0;
 117     }
 118
 119   file = read_envblk_file ((state[0].set) ? state[0].arg : 0, 0);
 120   if (! file)
 121     return grub_errno;
 122
 123   grub_file_close (file);
 124
 125   grub_envblk_iterate (envblk, hook);
 126
 127   return grub_errno;
 128 }
 129
 130 static grub_err_t
 131 grub_cmd_list_env (struct grub_arg_list *state,
 132                    int argc __attribute__ ((unused)), char **args __attribute__ ((unused)))
 133 {
 134   grub_file_t file;
 135
 136   auto int hook (char *name, char *value);
 137   int hook (char *name, char *value)
 138     {
 139       grub_printf ("%s=%s\n", name, value);
 140
 141       return 0;
 142     }
 143
 144   file = read_envblk_file ((state[0].set) ? state[0].arg : 0, 0);
 145   if (! file)
 146     return grub_errno;
 147
 148   grub_file_close (file);
 149
 150   grub_envblk_iterate (envblk, hook);
 151
 152   return grub_errno;
 153 }
 154
 155 static grub_err_t
 156 grub_cmd_save_env (struct grub_arg_list *state, int argc, char **args)
 157 {
 158   grub_file_t file;
 159   grub_disk_t disk;
 160   grub_disk_addr_t addr[GRUB_ENVBLK_MAXLEN >> GRUB_DISK_SECTOR_BITS];
 161   char buf[GRUB_DISK_SECTOR_SIZE];
 162   grub_disk_addr_t part_start = 0;
 163   int num = 0;
 164
 165   auto void NESTED_FUNC_ATTR hook (grub_disk_addr_t sector, unsigned offset,
 166                                    unsigned length);
 167
 168   void NESTED_FUNC_ATTR hook (grub_disk_addr_t sector,
 169                               unsigned offset, unsigned length)
 170     {
 171       if ((offset != 0) || (length != GRUB_DISK_SECTOR_SIZE))
 172         return;
 173
 174       if (num < (GRUB_ENVBLK_MAXLEN >> GRUB_DISK_SECTOR_BITS))
 175         addr[num++] = sector;
 176     }
 177
 178   if (! argc)
 179     return grub_error (GRUB_ERR_BAD_ARGUMENT, "No variable is specified");
 180
 181   file = read_envblk_file ((state[0].set) ? state[0].arg : 0, hook);
 182   if (! file)
 183     return grub_errno;
 184
 185   file->read_hook = 0;
 186
 187   if (num != GRUB_ENVBLK_MAXLEN >> GRUB_DISK_SECTOR_BITS)
 188     {
 189       grub_error (GRUB_ERR_BAD_DEVICE, "invalid blocklist");
 190       goto quit;
 191     }
 192
 193   disk = file->device->disk;
 194   if (disk->partition)
 195     part_start = grub_partition_get_start (disk->partition);
 196
 197   for (num = 0; num < (GRUB_ENVBLK_MAXLEN >> GRUB_DISK_SECTOR_BITS); num++)
 198     {
 199       if (grub_disk_read (disk, addr[num] - part_start, 0,
 200                           GRUB_DISK_SECTOR_SIZE,  buf))
 201         goto quit;
 202
 203       if (grub_memcmp (&buffer[num << GRUB_DISK_SECTOR_BITS], buf,
 204                        GRUB_DISK_SECTOR_SIZE))
 205         {
 206           grub_error (GRUB_ERR_BAD_DEVICE, "invalid blocklist");
 207           goto quit;
 208         }
 209     }
 210
 211   while (argc)
 212     {
 213       char *value;
 214
 215       value = grub_env_get (args[0]);
 216       if (value)
 217         {
 218           if (grub_envblk_insert (envblk, args[0], value))
 219             {
 220               grub_error (GRUB_ERR_BAD_ARGUMENT, "environment block too small");
 221               goto quit;
 222             }
 223         }
 224
 225       argc--;
 226       args++;
 227     }
 228
 229   for (num = 0; num < (GRUB_ENVBLK_MAXLEN >> GRUB_DISK_SECTOR_BITS); num++)
 230     if (grub_disk_write (disk, addr[num] - part_start, 0,
 231                          GRUB_DISK_SECTOR_SIZE,
 232                          &buffer[num << GRUB_DISK_SECTOR_BITS]))
 233       goto quit;
 234
 235 quit:
 236   grub_file_close (file);
 237
 238   return grub_errno;
 239 }
 240
 241 GRUB_MOD_INIT(loadenv)
 242 {
 243   (void) mod;
 244   grub_register_command ("load_env", grub_cmd_load_env, GRUB_COMMAND_FLAG_BOTH,
 245                          "load_env [-f FILE]", "Load variables from environment block file.", options);
 246   grub_register_command ("list_env", grub_cmd_list_env, GRUB_COMMAND_FLAG_BOTH,
 247                          "list_env [-f FILE]", "List variables from environment block file.", options);
 248   grub_register_command ("save_env", grub_cmd_save_env, GRUB_COMMAND_FLAG_BOTH,
 249                          "save_env [-f FILE] variable_name [...]", "Save variables to environment block file.", options);
 250 }
 251
 252 GRUB_MOD_FINI(loadenv)
 253 {
 254   grub_unregister_command ("load_env");
 255   grub_unregister_command ("list_env");
 256   grub_unregister_command ("save_env");
 257 }