166 lines
3.8 KiB
C
166 lines
3.8 KiB
C
/* chainloader.c - boot another boot loader */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2004,2007 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/loader.h>
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#include <grub/machine/loader.h>
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#include <grub/machine/chainloader.h>
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#include <grub/file.h>
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#include <grub/err.h>
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#include <grub/device.h>
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#include <grub/disk.h>
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#include <grub/misc.h>
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#include <grub/types.h>
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#include <grub/machine/init.h>
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#include <grub/partition.h>
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#include <grub/machine/memory.h>
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#include <grub/dl.h>
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#include <grub/command.h>
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static grub_dl_t my_mod;
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static int boot_drive;
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static void *boot_part_addr;
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static grub_err_t
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grub_chainloader_boot (void)
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{
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grub_chainloader_real_boot (boot_drive, boot_part_addr);
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/* Never reach here. */
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return GRUB_ERR_NONE;
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}
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static grub_err_t
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grub_chainloader_unload (void)
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{
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grub_dl_unref (my_mod);
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return GRUB_ERR_NONE;
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}
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static void
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grub_chainloader_cmd (const char *filename, grub_chainloader_flags_t flags)
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{
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grub_file_t file = 0;
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grub_uint16_t signature;
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grub_device_t dev;
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int drive = -1;
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void *part_addr = 0;
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grub_dl_ref (my_mod);
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file = grub_file_open (filename);
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if (! file)
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goto fail;
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/* Read the first block. */
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if (grub_file_read (file, (char *) 0x7C00, GRUB_DISK_SECTOR_SIZE)
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!= GRUB_DISK_SECTOR_SIZE)
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{
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if (grub_errno == GRUB_ERR_NONE)
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grub_error (GRUB_ERR_BAD_OS, "too small");
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goto fail;
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}
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/* Check the signature. */
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signature = *((grub_uint16_t *) (0x7C00 + GRUB_DISK_SECTOR_SIZE - 2));
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if (signature != grub_le_to_cpu16 (0xaa55)
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&& ! (flags & GRUB_CHAINLOADER_FORCE))
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{
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grub_error (GRUB_ERR_BAD_OS, "invalid signature");
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goto fail;
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}
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grub_file_close (file);
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/* Obtain the partition table from the root device. */
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dev = grub_device_open (0);
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if (dev)
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{
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grub_disk_t disk = dev->disk;
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if (disk)
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{
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grub_partition_t p = disk->partition;
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/* In i386-pc, the id is equal to the BIOS drive number. */
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drive = (int) disk->id;
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if (p)
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{
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grub_disk_read (disk, p->offset, 446, 64,
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(void *) GRUB_MEMORY_MACHINE_PART_TABLE_ADDR);
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part_addr = (void *) (GRUB_MEMORY_MACHINE_PART_TABLE_ADDR
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+ (p->index << 4));
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}
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}
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grub_device_close (dev);
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}
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/* Ignore errors. Perhaps it's not fatal. */
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grub_errno = GRUB_ERR_NONE;
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boot_drive = drive;
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boot_part_addr = part_addr;
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grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 1);
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return;
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fail:
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if (file)
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grub_file_close (file);
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grub_dl_unref (my_mod);
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}
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static grub_err_t
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grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
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int argc, char *argv[])
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{
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grub_chainloader_flags_t flags = 0;
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if (argc > 0 && grub_strcmp (argv[0], "--force") == 0)
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{
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flags |= GRUB_CHAINLOADER_FORCE;
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argc--;
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argv++;
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}
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if (argc == 0)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified");
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else
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grub_chainloader_cmd (argv[0], flags);
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return grub_errno;
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}
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static grub_command_t cmd;
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GRUB_MOD_INIT(chainloader)
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{
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cmd = grub_register_command ("chainloader", grub_cmd_chainloader,
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0, "load another boot loader");
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my_mod = mod;
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}
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GRUB_MOD_FINI(chainloader)
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{
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grub_unregister_command (cmd);
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}
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