278 lines
6.8 KiB
C
278 lines
6.8 KiB
C
/* multiboot.c - boot a multiboot OS image. */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009 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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/*
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* FIXME: The following features from the Multiboot specification still
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* need to be implemented:
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* - VBE support
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* - symbol table
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* - drives table
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* - ROM configuration table
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* - APM table
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*/
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/* The bits in the required part of flags field we don't support. */
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#define UNSUPPORTED_FLAGS 0x0000fff0
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#include <grub/loader.h>
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#include <grub/multiboot.h>
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#include <grub/machine/memory.h>
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#include <grub/elf.h>
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#include <grub/aout.h>
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#include <grub/file.h>
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#include <grub/err.h>
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#include <grub/dl.h>
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#include <grub/mm.h>
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#include <grub/misc.h>
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#include <grub/gzio.h>
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#include <grub/env.h>
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#include <grub/i386/relocator.h>
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extern grub_dl_t my_mod;
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struct grub_relocator *grub_multiboot_relocator = NULL;
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static grub_uint32_t grub_multiboot_payload_eip;
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static grub_err_t
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grub_multiboot_boot (void)
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{
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grub_err_t err;
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struct grub_relocator32_state state =
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{
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.eax = MULTIBOOT_BOOTLOADER_MAGIC,
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.ecx = 0,
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.edx = 0,
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.eip = grub_multiboot_payload_eip,
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/* Set esp to some random location in low memory to avoid breaking
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non-compliant kernels. */
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.esp = 0x7ff00
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};
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err = grub_multiboot_make_mbi (&state.ebx);
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if (err)
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return err;
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grub_relocator32_boot (grub_multiboot_relocator, state);
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/* Not reached. */
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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_multiboot_unload (void)
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{
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grub_multiboot_free_mbi ();
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grub_relocator_unload (grub_multiboot_relocator);
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grub_multiboot_relocator = NULL;
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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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#define MULTIBOOT_LOAD_ELF64
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#include "multiboot_elfxx.c"
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#undef MULTIBOOT_LOAD_ELF64
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#define MULTIBOOT_LOAD_ELF32
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#include "multiboot_elfxx.c"
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#undef MULTIBOOT_LOAD_ELF32
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/* Load ELF32 or ELF64. */
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static grub_err_t
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grub_multiboot_load_elf (grub_file_t file, void *buffer)
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{
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if (grub_multiboot_is_elf32 (buffer))
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return grub_multiboot_load_elf32 (file, buffer);
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else if (grub_multiboot_is_elf64 (buffer))
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return grub_multiboot_load_elf64 (file, buffer);
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return grub_error (GRUB_ERR_UNKNOWN_OS, "unknown ELF class");
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}
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void
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grub_multiboot (int argc, char *argv[])
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{
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grub_file_t file = 0;
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char buffer[MULTIBOOT_SEARCH];
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struct multiboot_header *header;
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grub_ssize_t len;
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grub_err_t err;
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grub_loader_unset ();
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if (argc == 0)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, "no kernel specified");
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goto fail;
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}
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file = grub_gzfile_open (argv[0], 1);
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if (! file)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, "couldn't open file");
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goto fail;
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}
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len = grub_file_read (file, buffer, MULTIBOOT_SEARCH);
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if (len < 32)
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{
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grub_error (GRUB_ERR_BAD_OS, "file too small");
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goto fail;
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}
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/* Look for the multiboot header in the buffer. The header should
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be at least 12 bytes and aligned on a 4-byte boundary. */
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for (header = (struct multiboot_header *) buffer;
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((char *) header <= buffer + len - 12) || (header = 0);
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header = (struct multiboot_header *) ((char *) header + 4))
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{
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if (header->magic == MULTIBOOT_HEADER_MAGIC
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&& !(header->magic + header->flags + header->checksum))
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break;
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}
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if (header == 0)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, "no multiboot header found");
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goto fail;
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}
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if (header->flags & UNSUPPORTED_FLAGS)
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{
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grub_error (GRUB_ERR_UNKNOWN_OS,
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"unsupported flag: 0x%x", header->flags);
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goto fail;
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}
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grub_relocator_unload (grub_multiboot_relocator);
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grub_multiboot_relocator = NULL;
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/* Skip filename. */
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grub_multiboot_init_mbi (argc - 1, argv + 1);
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grub_multiboot_relocator = grub_relocator_new ();
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if (!grub_multiboot_relocator)
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goto fail;
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if (header->flags & MULTIBOOT_AOUT_KLUDGE)
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{
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int offset = ((char *) header - buffer -
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(header->header_addr - header->load_addr));
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int load_size = ((header->load_end_addr == 0) ? file->size - offset :
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header->load_end_addr - header->load_addr);
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grub_size_t code_size;
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void *source;
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if (header->bss_end_addr)
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code_size = (header->bss_end_addr - header->load_addr);
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else
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code_size = load_size;
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err = grub_relocator_alloc_chunk_addr (grub_multiboot_relocator,
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&source, header->load_addr,
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code_size);
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if (err)
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{
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grub_dprintf ("multiboot_loader", "Error loading aout kludge\n");
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goto fail;
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}
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if ((grub_file_seek (file, offset)) == (grub_off_t) -1)
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goto fail;
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grub_file_read (file, source, load_size);
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if (grub_errno)
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goto fail;
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if (header->bss_end_addr)
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grub_memset ((grub_uint32_t *) source + load_size, 0,
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header->bss_end_addr - header->load_addr - load_size);
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grub_multiboot_payload_eip = header->entry_addr;
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}
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else if (grub_multiboot_load_elf (file, buffer) != GRUB_ERR_NONE)
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goto fail;
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grub_multiboot_set_bootdev ();
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grub_loader_set (grub_multiboot_boot, grub_multiboot_unload, 0);
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fail:
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if (file)
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grub_file_close (file);
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if (grub_errno != GRUB_ERR_NONE)
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{
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grub_relocator_unload (grub_multiboot_relocator);
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grub_dl_unref (my_mod);
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}
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}
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void
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grub_module (int argc, char *argv[])
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{
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grub_file_t file = 0;
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grub_ssize_t size;
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void *module = NULL;
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grub_addr_t target;
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grub_err_t err;
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if (argc == 0)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT, "no module specified");
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goto fail;
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}
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if (!grub_multiboot_relocator)
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{
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grub_error (GRUB_ERR_BAD_ARGUMENT,
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"you need to load the multiboot kernel first");
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goto fail;
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}
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file = grub_gzfile_open (argv[0], 1);
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if (! file)
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goto fail;
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size = grub_file_size (file);
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err = grub_relocator_alloc_chunk_align (grub_multiboot_relocator, &module,
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&target,
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0, (0xffffffff - size) + 1,
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size, MULTIBOOT_MOD_ALIGN,
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GRUB_RELOCATOR_PREFERENCE_NONE);
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if (err)
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goto fail;
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err = grub_multiboot_add_module (target, size, argc - 1, argv + 1);
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if (err)
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goto fail;
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if (grub_file_read (file, module, size) != size)
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{
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grub_error (GRUB_ERR_FILE_READ_ERROR, "couldn't read file");
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goto fail;
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}
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fail:
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if (file)
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grub_file_close (file);
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}
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