/* boot.c - command to boot an operating system */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2003,2004,2005,2007,2009  Free Software Foundation, Inc.
 *
 *  GRUB is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/normal.h>
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/loader.h>
#include <grub/kernel.h>

static grub_err_t (*grub_loader_boot_func) (void);
static grub_err_t (*grub_loader_unload_func) (void);
static int grub_loader_noreturn;

static int grub_loader_loaded;

int
grub_loader_is_loaded (void)
{
  return grub_loader_loaded;
}

void
grub_loader_set (grub_err_t (*boot) (void),
		 grub_err_t (*unload) (void),
		 int noreturn)
{
  if (grub_loader_loaded && grub_loader_unload_func)
    grub_loader_unload_func ();
  
  grub_loader_boot_func = boot;
  grub_loader_unload_func = unload;
  grub_loader_noreturn = noreturn;
  
  grub_loader_loaded = 1;
}

void
grub_loader_unset(void)
{
  if (grub_loader_loaded && grub_loader_unload_func)
    grub_loader_unload_func ();
  
  grub_loader_boot_func = 0;
  grub_loader_unload_func = 0;

  grub_loader_loaded = 0;
}

grub_err_t
grub_loader_boot (void)
{
  if (! grub_loader_loaded)
    return grub_error (GRUB_ERR_NO_KERNEL, "no loaded kernel");

  if (grub_loader_noreturn)
    grub_machine_fini ();
  
  return (grub_loader_boot_func) ();
}


/* boot */
static grub_err_t
grub_cmd_boot (struct grub_command *cmd __attribute__ ((unused)),
		    int argc __attribute__ ((unused)),
		    char *argv[] __attribute__ ((unused)))
{
  return grub_loader_boot ();
}



static grub_command_t cmd_boot;

GRUB_MOD_INIT(boot)
{
  (void) mod;			/* To stop warning. */
  cmd_boot =
    grub_register_command ("boot", grub_cmd_boot,
			   0, "boot an operating system");
}

GRUB_MOD_FINI(boot)
{
  grub_unregister_command (cmd_boot);
}