kern/main.c

   1 /* main.c - the kernel main routine */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2003,2005,2006,2008  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/kernel.h>
  21 #include <grub/misc.h>
  22 #include <grub/symbol.h>
  23 #include <grub/dl.h>
  24 #include <grub/term.h>
  25 #include <grub/file.h>
  26 #include <grub/device.h>
  27 #include <grub/env.h>
  28 #include <grub/mm.h>
  29 #include <grub/command.h>
  30 #include <grub/reader.h>
  31 #include <grub/parser.h>
  32
  33 void
  34 grub_module_iterate (int (*hook) (struct grub_module_header *header))
  35 {
  36   struct grub_module_info *modinfo;
  37   struct grub_module_header *header;
  38   grub_addr_t modbase;
  39
  40   modbase = grub_arch_modules_addr ();
  41   modinfo = (struct grub_module_info *) modbase;
  42
  43   /* Check if there are any modules.  */
  44   if ((modinfo == 0) || modinfo->magic != GRUB_MODULE_MAGIC)
  45     return;
  46
  47   for (header = (struct grub_module_header *) (modbase + modinfo->offset);
  48        header < (struct grub_module_header *) (modbase + modinfo->size);
  49        header = (struct grub_module_header *) ((char *) header + header->size))
  50     {
  51       if (hook (header))
  52         break;
  53     }
  54 }
  55
  56 /* Load all modules in core.  */
  57 static void
  58 grub_load_modules (void)
  59 {
  60   auto int hook (struct grub_module_header *);
  61   int hook (struct grub_module_header *header)
  62     {
  63       /* Not an ELF module, skip.  */
  64       if (header->type != OBJ_TYPE_ELF)
  65         return 0;
  66
  67       if (! grub_dl_load_core ((char *) header + sizeof (struct grub_module_header),
  68                                (header->size - sizeof (struct grub_module_header))))
  69         grub_fatal ("%s", grub_errmsg);
  70
  71       return 0;
  72     }
  73
  74   grub_module_iterate (hook);
  75 }
  76
  77 static void
  78 grub_load_config (void)
  79 {
  80   auto int hook (struct grub_module_header *);
  81   int hook (struct grub_module_header *header)
  82     {
  83       /* Not an ELF module, skip.  */
  84       if (header->type != OBJ_TYPE_CONFIG)
  85         return 0;
  86
  87       grub_parser_execute ((char *) header +
  88                            sizeof (struct grub_module_header));
  89       return 1;
  90     }
  91
  92   grub_module_iterate (hook);
  93 }
  94
  95 /* Write hook for the environment variables of root. Remove surrounding
  96    parentheses, if any.  */
  97 static char *
  98 grub_env_write_root (struct grub_env_var *var __attribute__ ((unused)),
  99                      const char *val)
 100 {
 101   /* XXX Is it better to check the existence of the device?  */
 102   grub_size_t len = grub_strlen (val);
 103
 104   if (val[0] == '(' && val[len - 1] == ')')
 105     return grub_strndup (val + 1, len - 2);
 106
 107   return grub_strdup (val);
 108 }
 109
 110 /* Set the root device according to the dl prefix.  */
 111 static void
 112 grub_set_root_dev (void)
 113 {
 114   const char *prefix;
 115
 116   grub_register_variable_hook ("root", 0, grub_env_write_root);
 117   grub_env_export ("root");
 118
 119   prefix = grub_env_get ("prefix");
 120
 121   if (prefix)
 122     {
 123       char *dev;
 124
 125       dev = grub_file_get_device_name (prefix);
 126       if (dev)
 127         {
 128           grub_env_set ("root", dev);
 129           grub_free (dev);
 130         }
 131     }
 132 }
 133
 134 /* Load the normal mode module and execute the normal mode if possible.  */
 135 static void
 136 grub_load_normal_mode (void)
 137 {
 138   /* Load the module.  */
 139   grub_dl_load ("normal");
 140
 141   /* Something went wrong.  Print errors here to let user know why we're entering rescue mode.  */
 142   grub_print_error ();
 143   grub_errno = 0;
 144
 145   grub_command_execute ("normal", 0, 0);
 146 }
 147
 148 /* The main routine.  */
 149 void
 150 grub_main (void)
 151 {
 152   /* First of all, initialize the machine.  */
 153   grub_machine_init ();
 154
 155   /* Hello.  */
 156   grub_setcolorstate (GRUB_TERM_COLOR_HIGHLIGHT);
 157   grub_printf ("Welcome to GRUB!\n\n");
 158   grub_setcolorstate (GRUB_TERM_COLOR_STANDARD);
 159
 160   /* Load pre-loaded modules and free the space.  */
 161   grub_register_exported_symbols ();
 162   grub_load_modules ();
 163
 164   /* It is better to set the root device as soon as possible,
 165      for convenience.  */
 166   grub_machine_set_prefix ();
 167   grub_env_export ("prefix");
 168   grub_set_root_dev ();
 169
 170   grub_register_core_commands ();
 171   grub_register_rescue_parser ();
 172   grub_register_rescue_reader ();
 173
 174   grub_load_config ();
 175   grub_load_normal_mode ();
 176   grub_reader_loop (0);
 177 }