grub/loader/i386/pc/chainloader.c
okuji 4b13b216f4 2004-04-04 Yoshinori K. Okuji <okuji@enbug.org>
All symbols prefixed with PUPA_ and pupa_ are renamed to GRUB_
	and grub_, respectively. Because the conversion is trivial and
	mechanical, I omit the details here. Please refer to the CVS
	if you need more information.
2004-04-04 13:46:03 +00:00

153 lines
3.5 KiB
C

/* chainloader.c - boot another boot loader */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002 Free Software Foundation, Inc.
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/loader.h>
#include <grub/machine/loader.h>
#include <grub/file.h>
#include <grub/err.h>
#include <grub/device.h>
#include <grub/disk.h>
#include <grub/misc.h>
#include <grub/types.h>
#include <grub/machine/init.h>
#include <grub/machine/partition.h>
#include <grub/machine/memory.h>
#include <grub/rescue.h>
#include <grub/dl.h>
static grub_dl_t my_mod;
static grub_err_t
grub_chainloader_boot (void)
{
grub_device_t dev;
int drive = -1;
void *part_addr = 0;
/* Open the root device. */
dev = grub_device_open (0);
if (dev)
{
grub_disk_t disk = dev->disk;
if (disk)
{
grub_partition_t p = disk->partition;
/* In i386-pc, the id is equal to the BIOS drive number. */
drive = (int) disk->id;
if (p)
{
grub_disk_read (disk, p->offset, 446, 64,
(char *) GRUB_MEMORY_MACHINE_PART_TABLE_ADDR);
/* Ignore errors. Perhaps it's not fatal. */
part_addr = (void *) (GRUB_MEMORY_MACHINE_PART_TABLE_ADDR
+ (p->index << 4));
}
}
grub_device_close (dev);
}
grub_chainloader_real_boot (drive, part_addr);
/* Never reach here. */
return GRUB_ERR_NONE;
}
static grub_err_t
grub_chainloader_unload (void)
{
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
}
void
grub_rescue_cmd_chainloader (int argc, char *argv[])
{
grub_file_t file = 0;
grub_uint16_t signature;
int force = 0;
grub_dl_ref (my_mod);
if (argc > 0 && grub_strcmp (argv[0], "--force") == 0)
{
force = 1;
argc--;
argv++;
}
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified");
goto fail;
}
file = grub_file_open (argv[0]);
if (! file)
goto fail;
/* Read the first block. */
if (grub_file_read (file, (char *) 0x7C00, GRUB_DISK_SECTOR_SIZE)
!= GRUB_DISK_SECTOR_SIZE)
{
if (grub_errno == GRUB_ERR_NONE)
grub_error (GRUB_ERR_BAD_OS, "too small");
goto fail;
}
/* Check the signature. */
signature = *((grub_uint16_t *) (0x7C00 + GRUB_DISK_SECTOR_SIZE - 2));
if (signature != grub_le_to_cpu16 (0xaa55) && ! force)
{
grub_error (GRUB_ERR_BAD_OS, "invalid signature");
goto fail;
}
grub_file_close (file);
grub_loader_set (grub_chainloader_boot, grub_chainloader_unload);
return;
fail:
if (file)
grub_file_close (file);
grub_dl_unref (my_mod);
}
static const char loader_name[] = "chainloader";
GRUB_MOD_INIT
{
grub_rescue_register_command (loader_name,
grub_rescue_cmd_chainloader,
"load another boot loader");
my_mod = mod;
}
GRUB_MOD_FINI
{
grub_rescue_unregister_command (loader_name);
}