diff options
Diffstat (limited to 'grub-core/loader/i386/pc/chainloader.c')
| -rw-r--r-- | grub-core/loader/i386/pc/chainloader.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/grub-core/loader/i386/pc/chainloader.c b/grub-core/loader/i386/pc/chainloader.c new file mode 100644 index 0000000..794316b --- /dev/null +++ b/grub-core/loader/i386/pc/chainloader.c @@ -0,0 +1,177 @@ +/* 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/machine/loader.h> +#include <grub/machine/chainloader.h> +#include <grub/machine/memory.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/memory.h> +#include <grub/dl.h> +#include <grub/command.h> +#include <grub/msdos_partition.h> +#include <grub/machine/biosnum.h> +#include <grub/cpu/floppy.h> +#include <grub/i18n.h> +#include <grub/video.h> +#include <grub/mm.h> + +GRUB_MOD_LICENSE ("GPLv3+"); + +static grub_dl_t my_mod; +static int boot_drive; +static void *boot_part_addr; + +static grub_err_t +grub_chainloader_boot (void) +{ + grub_video_set_mode ("text", 0, 0); + grub_chainloader_real_boot (boot_drive, boot_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; +} + +static void +grub_chainloader_cmd (const char *filename, grub_chainloader_flags_t flags) +{ + grub_file_t file = 0; + grub_uint16_t signature; + grub_device_t dev; + int drive = -1; + void *part_addr = 0; + + grub_dl_ref (my_mod); + + grub_file_filter_disable_compression (); + file = grub_file_open (filename); + if (! file) + goto fail; + + /* Read the first block. */ + if (grub_file_read (file, (void *) 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) + && ! (flags & GRUB_CHAINLOADER_FORCE)) + { + grub_error (GRUB_ERR_BAD_OS, "invalid signature"); + goto fail; + } + + grub_file_close (file); + + /* Obtain the partition table from the root device. */ + drive = grub_get_root_biosnumber (); + dev = grub_device_open (0); + if (dev && dev->disk && dev->disk->partition) + { + grub_disk_t disk = dev->disk; + + if (disk) + { + grub_partition_t p = disk->partition; + + if (p && grub_strcmp (p->partmap->name, "msdos") == 0) + { + disk->partition = p->parent; + grub_disk_read (disk, p->offset, 446, 64, + (void *) GRUB_MEMORY_MACHINE_PART_TABLE_ADDR); + part_addr = (void *) (GRUB_MEMORY_MACHINE_PART_TABLE_ADDR + + (p->index << 4)); + disk->partition = p; + } + } + } + + if (dev) + grub_device_close (dev); + + /* Ignore errors. Perhaps it's not fatal. */ + grub_errno = GRUB_ERR_NONE; + + boot_drive = drive; + boot_part_addr = part_addr; + + grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 1); + return; + + fail: + + if (file) + grub_file_close (file); + + grub_dl_unref (my_mod); +} + +static grub_err_t +grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)), + int argc, char *argv[]) +{ + grub_chainloader_flags_t flags = 0; + + if (argc > 0 && grub_strcmp (argv[0], "--force") == 0) + { + flags |= GRUB_CHAINLOADER_FORCE; + argc--; + argv++; + } + + if (argc == 0) + return grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified"); + else + grub_chainloader_cmd (argv[0], flags); + + return grub_errno; +} + +static grub_command_t cmd; + +GRUB_MOD_INIT(chainloader) +{ + cmd = grub_register_command ("chainloader", grub_cmd_chainloader, + 0, N_("Load another boot loader.")); + my_mod = mod; +} + +GRUB_MOD_FINI(chainloader) +{ + grub_unregister_command (cmd); +} |