| /* 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); |
| } |