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/* chainloader.c - boot another boot loader */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2004,2007,2009,2010 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/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/partition.h>
#include <grub/dl.h>
#include <grub/command.h>
#include <grub/machine/biosnum.h>
#include <grub/i18n.h>
#include <grub/video.h>
#include <grub/mm.h>
#include <grub/cpu/relocator.h>
#include <grub/machine/chainloader.h>
GRUB_MOD_LICENSE ("GPLv3+");
static grub_dl_t my_mod;
static struct grub_relocator *rel;
static grub_uint32_t ebx = 0xffffffff;
#define GRUB_FREEDOS_SEGMENT 0x60
#define GRUB_FREEDOS_ADDR (GRUB_FREEDOS_SEGMENT << 4)
#define GRUB_FREEDOS_STACK_SEGMENT 0x1fe0
#define GRUB_FREEDOS_STACK_BPB_POINTER 0x7c00
#define GRUB_FREEDOS_BPB_ADDR ((GRUB_FREEDOS_STACK_SEGMENT << 4) \
+ GRUB_FREEDOS_STACK_BPB_POINTER)
/* FreeDOS boot.asm passes register sp as exactly this. Importantly,
it must point below the BPB (to avoid overwriting any of it). */
#define GRUB_FREEDOS_STACK_POINTER (GRUB_FREEDOS_STACK_BPB_POINTER \
- 0x60)
/* In this, the additional 8192 bytes are the stack reservation; the
remaining parts trivially give the maximum allowed size. */
#define GRUB_FREEDOS_MAX_SIZE ((GRUB_FREEDOS_STACK_SEGMENT << 4) \
+ GRUB_FREEDOS_STACK_POINTER \
- GRUB_FREEDOS_ADDR \
- 8192)
static grub_err_t
grub_freedos_boot (void)
{
struct grub_relocator16_state state = {
.cs = GRUB_FREEDOS_SEGMENT,
.ip = 0,
.ds = GRUB_FREEDOS_STACK_SEGMENT,
.es = 0,
.fs = 0,
.gs = 0,
.ss = GRUB_FREEDOS_STACK_SEGMENT,
.sp = GRUB_FREEDOS_STACK_POINTER,
.ebp = GRUB_FREEDOS_STACK_BPB_POINTER,
.ebx = ebx,
.edx = ebx,
.a20 = 1
};
grub_video_set_mode ("text", 0, 0);
return grub_relocator16_boot (rel, state);
}
static grub_err_t
grub_freedos_unload (void)
{
grub_relocator_unload (rel);
rel = NULL;
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
}
static grub_err_t
grub_cmd_freedos (grub_command_t cmd __attribute__ ((unused)),
int argc, char *argv[])
{
grub_file_t file = 0;
grub_err_t err;
void *bs, *kernelsys;
grub_size_t kernelsyssize;
grub_device_t dev;
if (argc == 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
grub_dl_ref (my_mod);
rel = grub_relocator_new ();
if (!rel)
goto fail;
file = grub_file_open (argv[0], GRUB_FILE_TYPE_FREEDOS);
if (! file)
goto fail;
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_FREEDOS_BPB_ADDR,
GRUB_DISK_SECTOR_SIZE);
if (err)
goto fail;
bs = get_virtual_current_address (ch);
}
ebx = grub_get_root_biosnumber ();
dev = grub_device_open (0);
if (dev && dev->disk)
{
err = grub_disk_read (dev->disk, 0, 0, GRUB_DISK_SECTOR_SIZE, bs);
if (err)
{
grub_device_close (dev);
goto fail;
}
grub_chainloader_patch_bpb (bs, dev, ebx);
}
if (dev)
grub_device_close (dev);
kernelsyssize = grub_file_size (file);
if (kernelsyssize > GRUB_FREEDOS_MAX_SIZE)
{
grub_error (GRUB_ERR_BAD_OS,
N_("the size of `%s' is too large"), argv[0]);
goto fail;
}
{
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_FREEDOS_ADDR,
kernelsyssize);
if (err)
goto fail;
kernelsys = get_virtual_current_address (ch);
}
if (grub_file_read (file, kernelsys, kernelsyssize)
!= (grub_ssize_t) kernelsyssize)
goto fail;
grub_loader_set (grub_freedos_boot, grub_freedos_unload, 1);
return GRUB_ERR_NONE;
fail:
if (file)
grub_file_close (file);
grub_freedos_unload ();
return grub_errno;
}
static grub_command_t cmd;
GRUB_MOD_INIT(freedos)
{
cmd = grub_register_command ("freedos", grub_cmd_freedos,
0, N_("Load FreeDOS kernel.sys."));
my_mod = mod;
}
GRUB_MOD_FINI(freedos)
{
grub_unregister_command (cmd);
}
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