arch/common/boot/grub2/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/mm.h>
  23 #include <grub/symbol.h>
  24 #include <grub/dl.h>
  25 #include <grub/term.h>
  26 #include <grub/rescue.h>
  27 #include <grub/file.h>
  28 #include <grub/device.h>
  29 #include <grub/env.h>
  30
  31 /* Load all modules in core.  */
  32 static void
  33 grub_load_modules (void)
  34 {
  35   struct grub_module_info *modinfo;
  36   struct grub_module_header *header;
  37   grub_addr_t modbase;
  38
  39   modbase = grub_arch_modules_addr ();
  40   modinfo = (struct grub_module_info *) modbase;
  41
  42   /* Check if there are any modules.  */
  43   if ((modinfo == 0) || modinfo->magic != GRUB_MODULE_MAGIC)
  44     return;
  45
  46   for (header = (struct grub_module_header *) (modbase + modinfo->offset);
  47        header < (struct grub_module_header *) (modbase + modinfo->size);
  48        header = (struct grub_module_header *) ((char *) header + header->size))
  49     {
  50       if (! grub_dl_load_core ((char *) header + header->offset,
  51                                (header->size - header->offset)))
  52         grub_fatal ("%s", grub_errmsg);
  53     }
  54
  55   /* Add the region where modules reside into dynamic memory.  */
  56   grub_mm_init_region ((void *) modinfo, modinfo->size);
  57 }
  58
  59 /* Write hook for the environment variables of root. Remove surrounding
  60    parentheses, if any.  */
  61 static char *
  62 grub_env_write_root (struct grub_env_var *var __attribute__ ((unused)),
  63                      const char *val)
  64 {
  65   /* XXX Is it better to check the existence of the device?  */
  66   grub_size_t len = grub_strlen (val);
  67
  68   if (val[0] == '(' && val[len - 1] == ')')
  69     return grub_strndup (val + 1, len - 2);
  70
  71   return grub_strdup (val);
  72 }
  73
  74 /* Set the root device according to the dl prefix.  */
  75 static void
  76 grub_set_root_dev (void)
  77 {
  78   const char *prefix;
  79
  80   grub_register_variable_hook ("root", 0, grub_env_write_root);
  81   grub_env_export ("root");
  82
  83   prefix = grub_env_get ("prefix");
  84
  85   if (prefix)
  86     {
  87       char *dev;
  88
  89       dev = grub_file_get_device_name (prefix);
  90       if (dev)
  91         {
  92           grub_env_set ("root", dev);
  93           grub_free (dev);
  94         }
  95     }
  96 }
  97
  98 /* Load the normal mode module and execute the normal mode if possible.  */
  99 static void
 100 grub_load_normal_mode (void)
 101 {
 102   /* Load the module.  */
 103   grub_dl_load ("normal");
 104
 105   /* Something went wrong.  Print errors here to let user know why we're entering rescue mode.  */
 106   grub_print_error ();
 107 }
 108
 109 /* The main routine.  */
 110 void
 111 grub_main (void)
 112 {
 113   /* First of all, initialize the machine.  */
 114   grub_machine_init ();
 115
 116   /* Hello.  */
 117   grub_setcolorstate (GRUB_TERM_COLOR_HIGHLIGHT);
 118   grub_printf ("Welcome to GRUB!\n\n");
 119   grub_setcolorstate (GRUB_TERM_COLOR_STANDARD);
 120
 121   /* Load pre-loaded modules and free the space.  */
 122   grub_register_exported_symbols ();
 123   grub_load_modules ();
 124
 125   /* It is better to set the root device as soon as possible,
 126      for convenience.  */
 127   grub_machine_set_prefix ();
 128   grub_set_root_dev ();
 129
 130   /* Load the normal mode module.  */
 131   grub_load_normal_mode ();
 132
 133   /* Enter the rescue mode.  */
 134   grub_enter_rescue_mode ();
 135 }