grub-core/kern/main.c

   1 /* main.c - the kernel main routine */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2003,2005,2006,2008,2009  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 /* This is actualy platform-independant but used only on loongson and sparc.  */
  34 #if defined (GRUB_MACHINE_MIPS_LOONGSON) || defined (GRUB_MACHINE_MIPS_QEMU_MIPS) || defined (GRUB_MACHINE_SPARC64)
  35 grub_addr_t
  36 grub_modules_get_end (void)
  37 {
  38   struct grub_module_info *modinfo;
  39
  40   modinfo = (struct grub_module_info *) grub_modbase;
  41
  42   /* Check if there are any modules.  */
  43   if ((modinfo == 0) || modinfo->magic != GRUB_MODULE_MAGIC)
  44     return grub_modbase;
  45
  46   return grub_modbase + modinfo->size;
  47 }
  48 #endif
  49
  50 /* Load all modules in core.  */
  51 static void
  52 grub_load_modules (void)
  53 {
  54   struct grub_module_header *header;
  55   FOR_MODULES (header)
  56   {
  57     /* Not an ELF module, skip.  */
  58     if (header->type != OBJ_TYPE_ELF)
  59       continue;
  60
  61     if (! grub_dl_load_core ((char *) header + sizeof (struct grub_module_header),
  62                              (header->size - sizeof (struct grub_module_header))))
  63       grub_fatal ("%s", grub_errmsg);
  64
  65     if (grub_errno)
  66       grub_print_error ();
  67   }
  68 }
  69
  70 static void
  71 grub_load_config (void)
  72 {
  73   struct grub_module_header *header;
  74   FOR_MODULES (header)
  75   {
  76     /* Not an embedded config, skip.  */
  77     if (header->type != OBJ_TYPE_CONFIG)
  78       continue;
  79
  80     grub_parser_execute ((char *) header +
  81                          sizeof (struct grub_module_header));
  82     break;
  83   }
  84 }
  85
  86 /* Write hook for the environment variables of root. Remove surrounding
  87    parentheses, if any.  */
  88 static char *
  89 grub_env_write_root (struct grub_env_var *var __attribute__ ((unused)),
  90                      const char *val)
  91 {
  92   /* XXX Is it better to check the existence of the device?  */
  93   grub_size_t len = grub_strlen (val);
  94
  95   if (val[0] == '(' && val[len - 1] == ')')
  96     return grub_strndup (val + 1, len - 2);
  97
  98   return grub_strdup (val);
  99 }
 100
 101 static void
 102 grub_set_prefix_and_root (void)
 103 {
 104   char *device = NULL;
 105   char *path = NULL;
 106   char *fwdevice = NULL;
 107   char *fwpath = NULL;
 108   char *prefix = NULL;
 109   struct grub_module_header *header;
 110
 111   FOR_MODULES (header)
 112     if (header->type == OBJ_TYPE_PREFIX)
 113       prefix = (char *) header + sizeof (struct grub_module_header);
 114
 115   grub_register_variable_hook ("root", 0, grub_env_write_root);
 116
 117   if (prefix)
 118     {
 119       char *pptr = NULL;
 120       if (prefix[0] == '(')
 121         {
 122           pptr = grub_strrchr (prefix, ')');
 123           if (pptr)
 124             {
 125               device = grub_strndup (prefix + 1, pptr - prefix - 1);
 126               pptr++;
 127             }
 128         }
 129       if (!pptr)
 130         pptr = prefix;
 131       if (pptr[0])
 132         path = grub_strdup (pptr);
 133     }
 134   if ((!device || device[0] == ',' || !device[0]) || !path)
 135     grub_machine_get_bootlocation (&fwdevice, &fwpath);
 136
 137   if (!device && fwdevice)
 138     device = fwdevice;
 139   else if (fwdevice && (device[0] == ',' || !device[0]))
 140     {
 141       /* We have a partition, but still need to fill in the drive.  */
 142       char *comma, *new_device;
 143
 144       comma = grub_strchr (fwdevice, ',');
 145       if (comma)
 146         {
 147           char *drive = grub_strndup (fwdevice, comma - fwdevice);
 148           new_device = grub_xasprintf ("%s%s", drive, device);
 149           grub_free (drive);
 150         }
 151       else
 152         new_device = grub_xasprintf ("%s%s", fwdevice, device);
 153
 154       grub_free (fwdevice);
 155       grub_free (device);
 156       device = new_device;
 157     }
 158   if (fwpath && !path)
 159     path = fwpath;
 160   if (device)
 161     {
 162       char *prefix_set;
 163
 164       prefix_set = grub_xasprintf ("(%s)%s", device, path ? : "");
 165       if (prefix_set)
 166         {
 167           grub_env_set ("prefix", prefix_set);
 168           grub_free (prefix_set);
 169         }
 170       grub_env_set ("root", device);
 171     }
 172
 173   grub_free (device);
 174   grub_free (path);
 175   grub_print_error ();
 176 }
 177
 178 /* Load the normal mode module and execute the normal mode if possible.  */
 179 static void
 180 grub_load_normal_mode (void)
 181 {
 182   /* Load the module.  */
 183   grub_dl_load ("normal");
 184
 185   /* Print errors if any.  */
 186   grub_print_error ();
 187   grub_errno = 0;
 188
 189   grub_command_execute ("normal", 0, 0);
 190 }
 191
 192 /* The main routine.  */
 193 void __attribute__ ((noreturn))
 194 grub_main (void)
 195 {
 196   /* First of all, initialize the machine.  */
 197   grub_machine_init ();
 198
 199   /* Hello.  */
 200   grub_setcolorstate (GRUB_TERM_COLOR_HIGHLIGHT);
 201   grub_printf ("Welcome to GRUB!\n\n");
 202   grub_setcolorstate (GRUB_TERM_COLOR_STANDARD);
 203
 204   /* Load pre-loaded modules and free the space.  */
 205   grub_register_exported_symbols ();
 206 #ifdef GRUB_LINKER_HAVE_INIT
 207   grub_arch_dl_init_linker ();
 208 #endif
 209   grub_load_modules ();
 210
 211   /* It is better to set the root device as soon as possible,
 212      for convenience.  */
 213   grub_set_prefix_and_root ();
 214   grub_env_export ("root");
 215   grub_env_export ("prefix");
 216
 217   grub_register_core_commands ();
 218
 219   grub_load_config ();
 220   grub_load_normal_mode ();
 221   grub_rescue_run ();
 222 }