138 lines
3.4 KiB
C
138 lines
3.4 KiB
C
/* chainloader.c - boot another boot loader */
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/*
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* PUPA -- Preliminary Universal Programming Architecture for GRUB
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* Copyright (C) 2002 Yoshinori K. Okuji <okuji@enbug.org>
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*
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* This program 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 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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 this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <pupa/loader.h>
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#include <pupa/machine/loader.h>
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#include <pupa/file.h>
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#include <pupa/err.h>
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#include <pupa/device.h>
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#include <pupa/disk.h>
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#include <pupa/misc.h>
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#include <pupa/types.h>
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#include <pupa/machine/init.h>
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#include <pupa/machine/partition.h>
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#include <pupa/machine/memory.h>
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#include <pupa/rescue.h>
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#include <pupa/dl.h>
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/* Allocate space statically, because this is very small anyway. */
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static char pupa_chainloader_boot_sector[PUPA_DISK_SECTOR_SIZE];
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static pupa_err_t
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pupa_chainloader_boot (void)
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{
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pupa_device_t dev;
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int drive = -1;
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void *part_addr = 0;
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/* Open the root device. */
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dev = pupa_device_open (0);
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if (dev)
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{
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pupa_disk_t disk = dev->disk;
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if (disk)
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{
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pupa_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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pupa_disk_read (disk, p->offset, 446, 64,
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(char *) PUPA_MEMORY_MACHINE_PART_TABLE_ADDR);
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/* Ignore errors. Perhaps it's not fatal. */
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part_addr = (void *) (PUPA_MEMORY_MACHINE_PART_TABLE_ADDR
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+ (p->index << 4));
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}
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}
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pupa_device_close (dev);
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}
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pupa_chainloader_real_boot (drive, part_addr);
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/* Never reach here. */
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return PUPA_ERR_NONE;
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}
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static void
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pupa_rescue_cmd_chainloader (int argc, char *argv[])
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{
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pupa_file_t file;
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pupa_uint16_t signature;
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int force = 0;
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if (argc > 0 && pupa_strcmp (argv[0], "--force") == 0)
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{
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force = 1;
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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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{
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pupa_error (PUPA_ERR_BAD_ARGUMENT, "no file specified");
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return;
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}
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file = pupa_file_open (argv[0]);
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if (! file)
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return;
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/* Read the first block. */
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if (pupa_file_read (file, pupa_chainloader_boot_sector,
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PUPA_DISK_SECTOR_SIZE) != PUPA_DISK_SECTOR_SIZE)
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{
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if (pupa_errno == PUPA_ERR_NONE)
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pupa_error (PUPA_ERR_BAD_OS, "too small");
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pupa_file_close (file);
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return;
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}
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/* Check the signature. */
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signature = *((pupa_uint16_t *) (pupa_chainloader_boot_sector
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+ PUPA_DISK_SECTOR_SIZE - 2));
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if (signature != pupa_le_to_cpu16 (0xaa55) && ! force)
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pupa_error (PUPA_ERR_BAD_OS, "invalid signature");
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pupa_file_close (file);
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if (pupa_errno == PUPA_ERR_NONE)
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pupa_loader_set (0, pupa_chainloader_boot, 0);
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}
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static const char loader_name[] = "chainloader";
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PUPA_MOD_INIT
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{
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pupa_rescue_register_command (loader_name,
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pupa_rescue_cmd_chainloader,
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"load another boot loader");
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}
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PUPA_MOD_FINI
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{
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pupa_rescue_unregister_command (loader_name);
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}
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