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grub/loader/i386/pc/multiboot.c
robertmh 21751d508a 2008-08-31 Robert Millan <rmh@aybabtu.com> 
* loader/i386/pc/multiboot.c: Update comment not to say that
        boot_device support is unimplemented.
2008-08-31 19:25:41 +00:00

634 lines
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/* multiboot.c - boot a multiboot OS image. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2003,2004,2005,2007,2008 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/>.
*/
/*
* FIXME: The following features from the Multiboot specification still
* need to be implemented:
* - VBE support
* - symbol table
* - drives table
* - ROM configuration table
* - APM table
*/
#include <grub/loader.h>
#include <grub/machine/loader.h>
#include <grub/multiboot.h>
#include <grub/machine/init.h>
#include <grub/machine/memory.h>
#include <grub/elf.h>
#include <grub/aout.h>
#include <grub/file.h>
#include <grub/err.h>
#include <grub/rescue.h>
#include <grub/dl.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/gzio.h>
#include <grub/env.h>
extern grub_dl_t my_mod;
static struct grub_multiboot_info *mbi;
static grub_addr_t entry;
static char *playground = NULL;
static grub_err_t
grub_multiboot_boot (void)
{
grub_multiboot_real_boot (entry, mbi);
/* Not reached. */
return GRUB_ERR_NONE;
}
static grub_err_t
grub_multiboot_unload (void)
{
if (mbi)
{
unsigned int i;
for (i = 0; i < mbi->mods_count; i++)
{
grub_free ((void *)
((struct grub_mod_list *) mbi->mods_addr)[i].mod_start);
grub_free ((void *)
((struct grub_mod_list *) mbi->mods_addr)[i].cmdline);
}
grub_free ((void *) mbi->mods_addr);
grub_free ((void *) mbi->cmdline);
grub_free (mbi);
}
mbi = 0;
grub_dl_unref (my_mod);
return GRUB_ERR_NONE;
}
/* FIXME: grub_uint32_t will break for addresses above 4 GiB, but is mandated
by the spec. Is there something we can do about it? */
static grub_uint32_t mmap_addr = 0;
static grub_uint32_t mmap_length;
/* Return the length of the Multiboot mmap that will be needed to allocate
our platform's map. */
static grub_uint32_t
grub_get_multiboot_mmap_len ()
{
grub_size_t count = 0;
auto int NESTED_FUNC_ATTR hook (grub_uint64_t, grub_uint64_t, grub_uint32_t);
int NESTED_FUNC_ATTR hook (grub_uint64_t addr __attribute__ ((unused)),
grub_uint64_t size __attribute__ ((unused)),
grub_uint32_t type __attribute__ ((unused)))
{
count++;
return 0;
}
grub_machine_mmap_iterate (hook);
return count * sizeof (struct grub_multiboot_mmap_entry);
}
/* Fill previously allocated Multiboot mmap. */
static void
grub_fill_multiboot_mmap (struct grub_multiboot_mmap_entry *first_entry)
{
struct grub_multiboot_mmap_entry *mmap_entry = (struct grub_multiboot_mmap_entry *) first_entry;
auto int NESTED_FUNC_ATTR hook (grub_uint64_t, grub_uint64_t, grub_uint32_t);
int NESTED_FUNC_ATTR hook (grub_uint64_t addr, grub_uint64_t size, grub_uint32_t type)
{
mmap_entry->addr = addr;
mmap_entry->len = size;
mmap_entry->type = type;
mmap_entry->size = sizeof (struct grub_multiboot_mmap_entry) - sizeof (mmap_entry->size);
mmap_entry++;
return 0;
}
grub_machine_mmap_iterate (hook);
}
/* Check if BUFFER contains ELF32. */
static int
grub_multiboot_is_elf32 (void *buffer)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *) buffer;
return ehdr->e_ident[EI_CLASS] == ELFCLASS32;
}
static grub_err_t
grub_multiboot_load_elf32 (grub_file_t file, void *buffer)
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *) buffer;
char *phdr_base;
int lowest_segment = 0, highest_segment = 0;
int i;
if (ehdr->e_ident[EI_CLASS] != ELFCLASS32)
return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF class");
if (grub_dl_check_header (ehdr, sizeof(Elf32_Ehdr)))
return grub_error (GRUB_ERR_UNKNOWN_OS, "no valid ELF header found");
if (ehdr->e_type != ET_EXEC)
return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type");
/* FIXME: Should we support program headers at strange locations? */
if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
phdr_base = (char *) buffer + ehdr->e_phoff;
#define phdr(i) ((Elf32_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
for (i = 0; i < ehdr->e_phnum; i++)
if (phdr(i)->p_type == PT_LOAD)
{
if (phdr(i)->p_paddr < phdr(lowest_segment)->p_paddr)
lowest_segment = i;
if (phdr(i)->p_paddr > phdr(highest_segment)->p_paddr)
highest_segment = i;
}
grub_multiboot_payload_size += (phdr(highest_segment)->p_paddr + phdr(highest_segment)->p_memsz) - phdr(lowest_segment)->p_paddr;
grub_multiboot_payload_dest = phdr(lowest_segment)->p_paddr;
playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
if (! playground)
return grub_errno;
grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
/* Load every loadable segment in memory. */
for (i = 0; i < ehdr->e_phnum; i++)
{
if (phdr(i)->p_type == PT_LOAD)
{
char *load_this_module_at = (char *) (grub_multiboot_payload_orig + (phdr(i)->p_paddr - phdr(0)->p_paddr));
grub_dprintf ("multiboot_loader", "segment %d: paddr=%p, memsz=0x%x\n",
i, (void *) phdr(i)->p_paddr, phdr(i)->p_memsz);
if (grub_file_seek (file, (grub_off_t) phdr(i)->p_offset)
== (grub_off_t) -1)
return grub_error (GRUB_ERR_BAD_OS,
"invalid offset in program header");
if (grub_file_read (file, load_this_module_at, phdr(i)->p_filesz)
!= (grub_ssize_t) phdr(i)->p_filesz)
return grub_error (GRUB_ERR_BAD_OS,
"couldn't read segment from file");
if (phdr(i)->p_filesz < phdr(i)->p_memsz)
grub_memset (load_this_module_at + phdr(i)->p_filesz, 0,
phdr(i)->p_memsz - phdr(i)->p_filesz);
}
}
grub_multiboot_payload_entry_offset = ehdr->e_entry - phdr(lowest_segment)->p_vaddr;
#undef phdr
return grub_errno;
}
/* Check if BUFFER contains ELF64. */
static int
grub_multiboot_is_elf64 (void *buffer)
{
Elf64_Ehdr *ehdr = (Elf64_Ehdr *) buffer;
return ehdr->e_ident[EI_CLASS] == ELFCLASS64;
}
static grub_err_t
grub_multiboot_load_elf64 (grub_file_t file, void *buffer)
{
Elf64_Ehdr *ehdr = (Elf64_Ehdr *) buffer;
char *phdr_base;
grub_addr_t physical_entry_addr = 0;
int i;
if (ehdr->e_ident[EI_CLASS] != ELFCLASS64)
return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF class");
if (ehdr->e_ident[EI_MAG0] != ELFMAG0
|| ehdr->e_ident[EI_MAG1] != ELFMAG1
|| ehdr->e_ident[EI_MAG2] != ELFMAG2
|| ehdr->e_ident[EI_MAG3] != ELFMAG3
|| ehdr->e_version != EV_CURRENT
|| ehdr->e_ident[EI_DATA] != ELFDATA2LSB
|| ehdr->e_machine != EM_X86_64)
return grub_error(GRUB_ERR_UNKNOWN_OS, "no valid ELF header found");
if (ehdr->e_type != ET_EXEC)
return grub_error (GRUB_ERR_UNKNOWN_OS, "invalid ELF file type");
/* FIXME: Should we support program headers at strange locations? */
if (ehdr->e_phoff + ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
/* We still in 32-bit mode */
if (ehdr->e_entry > 0xffffffff)
return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
entry = ehdr->e_entry;
phdr_base = (char *) buffer + ehdr->e_phoff;
#define phdr(i) ((Elf64_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
/* Load every loadable segment in memory. */
for (i = 0; i < ehdr->e_phnum; i++)
{
if (phdr(i)->p_type == PT_LOAD)
{
/* The segment should fit in the area reserved for the OS. */
if (phdr(i)->p_paddr < (grub_uint64_t) grub_os_area_addr)
return grub_error (GRUB_ERR_BAD_OS,
"segment doesn't fit in memory reserved for the OS (0x%lx < 0x%lx)",
phdr(i)->p_paddr, (grub_uint64_t) grub_os_area_addr);
if (phdr(i)->p_paddr + phdr(i)->p_memsz
> (grub_uint64_t) grub_os_area_addr + (grub_uint64_t) grub_os_area_size)
return grub_error (GRUB_ERR_BAD_OS,
"segment doesn't fit in memory reserved for the OS (0x%lx > 0x%lx)",
phdr(i)->p_paddr + phdr(i)->p_memsz,
(grub_uint64_t) grub_os_area_addr + (grub_uint64_t) grub_os_area_size);
if (grub_file_seek (file, (grub_off_t) phdr(i)->p_offset)
== (grub_off_t) -1)
return grub_error (GRUB_ERR_BAD_OS,
"invalid offset in program header");
if (grub_file_read (file, (void *) ((grub_uint32_t) phdr(i)->p_paddr),
phdr(i)->p_filesz)
!= (grub_ssize_t) phdr(i)->p_filesz)
return grub_error (GRUB_ERR_BAD_OS,
"couldn't read segment from file");
if (phdr(i)->p_filesz < phdr(i)->p_memsz)
grub_memset (((char *) ((grub_uint32_t) phdr(i)->p_paddr)
+ phdr(i)->p_filesz),
0,
phdr(i)->p_memsz - phdr(i)->p_filesz);
if ((entry >= phdr(i)->p_vaddr) &&
(entry < phdr(i)->p_vaddr + phdr(i)->p_memsz))
physical_entry_addr = entry + phdr(i)->p_paddr - phdr(i)->p_vaddr;
}
}
#undef phdr
if (physical_entry_addr)
entry = physical_entry_addr;
return grub_errno;
}
/* Load ELF32 or ELF64. */
static grub_err_t
grub_multiboot_load_elf (grub_file_t file, void *buffer)
{
if (grub_multiboot_is_elf32 (buffer))
return grub_multiboot_load_elf32 (file, buffer);
else if (grub_multiboot_is_elf64 (buffer))
return grub_multiboot_load_elf64 (file, buffer);
return grub_error (GRUB_ERR_UNKNOWN_OS, "unknown ELF class");
}
static int
grub_multiboot_get_bootdev (grub_uint32_t *bootdev)
{
char *p;
p = grub_env_get ("root");
if ((p) && ((p[0] == 'h') || (p[0] == 'f')) && (p[1] == 'd') &&
(p[2] >= '0') && (p[2] <= '9'))
{
grub_uint32_t bd;
bd = (p[0] == 'h') ? 0x80 : 0;
bd += grub_strtoul (p + 2, &p, 0);
bd <<= 24;
if ((p) && (p[0] == ','))
{
if ((p[1] >= '0') && (p[1] <= '9'))
{
bd += ((grub_strtoul (p + 1, &p, 0) - 1) & 0xFF) << 16;
if ((p) && (p[0] == ','))
p++;
}
else
bd += 0xFF0000;
if ((p[0] >= 'a') && (p[0] <= 'z'))
bd += (p[0] - 'a') << 8;
else
bd += 0xFF00;
}
else
bd += 0xFFFF00;
bd += 0xFF;
*bootdev = bd;
return 1;
}
return 0;
}
void
grub_multiboot (int argc, char *argv[])
{
grub_file_t file = 0;
char buffer[MULTIBOOT_SEARCH], *cmdline = 0, *p;
struct grub_multiboot_header *header;
grub_ssize_t len;
int i;
grub_loader_unset ();
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "No kernel specified");
goto fail;
}
file = grub_gzfile_open (argv[0], 1);
if (! file)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "Couldn't open file");
goto fail;
}
len = grub_file_read (file, buffer, MULTIBOOT_SEARCH);
if (len < 32)
{
grub_error (GRUB_ERR_BAD_OS, "File too small");
goto fail;
}
/* Look for the multiboot header in the buffer. The header should
be at least 12 bytes and aligned on a 4-byte boundary. */
for (header = (struct grub_multiboot_header *) buffer;
((char *) header <= buffer + len - 12) || (header = 0);
header = (struct grub_multiboot_header *) ((char *) header + 4))
{
if (header->magic == MULTIBOOT_MAGIC
&& !(header->magic + header->flags + header->checksum))
break;
}
if (header == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "No multiboot header found");
goto fail;
}
if (header->flags & MULTIBOOT_UNSUPPORTED)
{
grub_error (GRUB_ERR_UNKNOWN_OS,
"Unsupported flag: 0x%x", header->flags);
goto fail;
}
if (playground)
{
grub_free (playground);
playground = NULL;
}
mmap_length = grub_get_multiboot_mmap_len ();
grub_multiboot_payload_size = mmap_length;
if (header->flags & MULTIBOOT_AOUT_KLUDGE)
{
int offset = ((char *) header - buffer -
(header->header_addr - header->load_addr));
int load_size = ((header->load_end_addr == 0) ? file->size - offset :
header->load_end_addr - header->load_addr);
if (header->bss_end_addr)
grub_multiboot_payload_size += (header->bss_end_addr - header->load_addr);
else
grub_multiboot_payload_size += load_size;
grub_multiboot_payload_dest = header->load_addr;
playground = grub_malloc (RELOCATOR_SIZEOF(forward) + grub_multiboot_payload_size + RELOCATOR_SIZEOF(backward));
if (! playground)
goto fail;
grub_multiboot_payload_orig = (long) playground + RELOCATOR_SIZEOF(forward);
if ((grub_file_seek (file, offset)) == (grub_off_t) - 1)
goto fail;
grub_file_read (file, grub_multiboot_payload_orig, load_size);
if (grub_errno)
goto fail;
if (header->bss_end_addr)
grub_memset (grub_multiboot_payload_orig + load_size, 0,
header->bss_end_addr - header->load_addr - load_size);
grub_multiboot_payload_entry_offset = header->entry_addr - header->load_addr;
}
else if (grub_multiboot_load_elf (file, buffer) != GRUB_ERR_NONE)
goto fail;
grub_fill_multiboot_mmap ((struct grub_mmap_entry *) (grub_multiboot_payload_orig
+ grub_multiboot_payload_size
- mmap_length));
mmap_addr = grub_multiboot_payload_dest + grub_multiboot_payload_size - mmap_length;
if (grub_multiboot_payload_dest >= grub_multiboot_payload_orig)
{
grub_memmove (playground, &grub_multiboot_forward_relocator, RELOCATOR_SIZEOF(forward));
entry = (grub_addr_t) playground;
}
else
{
grub_memmove ((char *) (grub_multiboot_payload_orig + grub_multiboot_payload_size),
&grub_multiboot_backward_relocator, RELOCATOR_SIZEOF(backward));
entry = (grub_addr_t) grub_multiboot_payload_orig + grub_multiboot_payload_size;
}
grub_dprintf ("multiboot_loader", "dest=%p, size=0x%x, entry_offset=0x%x\n",
(void *) grub_multiboot_payload_dest,
grub_multiboot_payload_size,
grub_multiboot_payload_entry_offset);
mbi = grub_malloc (sizeof (struct grub_multiboot_info));
if (! mbi)
goto fail;
grub_memset (mbi, 0, sizeof (struct grub_multiboot_info));
/* Convert from bytes to kilobytes. */
mbi->mem_lower = grub_lower_mem / 1024;
mbi->mem_upper = grub_upper_mem / 1024;
mbi->flags |= MULTIBOOT_INFO_MEMORY;
mbi->mmap_addr = mmap_addr;
mbi->mmap_length = mmap_length;
mbi->flags |= MULTIBOOT_INFO_MEM_MAP;
for (i = 0, len = 0; i < argc; i++)
len += grub_strlen (argv[i]) + 1;
cmdline = p = grub_malloc (len);
if (! cmdline)
goto fail;
for (i = 0; i < argc; i++)
{
p = grub_stpcpy (p, argv[i]);
*(p++) = ' ';
}
/* Remove the space after the last word. */
*(--p) = '\0';
mbi->flags |= MULTIBOOT_INFO_CMDLINE;
mbi->cmdline = (grub_uint32_t) cmdline;
mbi->flags |= MULTIBOOT_INFO_BOOT_LOADER_NAME;
mbi->boot_loader_name = (grub_uint32_t) grub_strdup (PACKAGE_STRING);
if (grub_multiboot_get_bootdev (&mbi->boot_device))
mbi->flags |= MULTIBOOT_INFO_BOOTDEV;
grub_loader_set (grub_multiboot_boot, grub_multiboot_unload, 1);
fail:
if (file)
grub_file_close (file);
if (grub_errno != GRUB_ERR_NONE)
{
grub_free (cmdline);
grub_free (mbi);
grub_dl_unref (my_mod);
}
}
void
grub_module (int argc, char *argv[])
{
grub_file_t file = 0;
grub_ssize_t size, len = 0;
char *module = 0, *cmdline = 0, *p;
int i;
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, "No module specified");
goto fail;
}
if (!mbi)
{
grub_error (GRUB_ERR_BAD_ARGUMENT,
"You need to load the multiboot kernel first");
goto fail;
}
file = grub_gzfile_open (argv[0], 1);
if (! file)
goto fail;
size = grub_file_size (file);
module = grub_memalign (MULTIBOOT_MOD_ALIGN, size);
if (! module)
goto fail;
if (grub_file_read (file, module, size) != size)
{
grub_error (GRUB_ERR_FILE_READ_ERROR, "Couldn't read file");
goto fail;
}
for (i = 0; i < argc; i++)
len += grub_strlen (argv[i]) + 1;
cmdline = p = grub_malloc (len);
if (! cmdline)
goto fail;
for (i = 0; i < argc; i++)
{
p = grub_stpcpy (p, argv[i]);
*(p++) = ' ';
}
/* Remove the space after the last word. */
*(--p) = '\0';
if (mbi->flags & MULTIBOOT_INFO_MODS)
{
struct grub_mod_list *modlist = (struct grub_mod_list *) mbi->mods_addr;
modlist = grub_realloc (modlist, (mbi->mods_count + 1)
* sizeof (struct grub_mod_list));
if (! modlist)
goto fail;
mbi->mods_addr = (grub_uint32_t) modlist;
modlist += mbi->mods_count;
modlist->mod_start = (grub_uint32_t) module;
modlist->mod_end = (grub_uint32_t) module + size;
modlist->cmdline = (grub_uint32_t) cmdline;
modlist->pad = 0;
mbi->mods_count++;
}
else
{
struct grub_mod_list *modlist = grub_malloc (sizeof (struct grub_mod_list));
if (! modlist)
goto fail;
modlist->mod_start = (grub_uint32_t) module;
modlist->mod_end = (grub_uint32_t) module + size;
modlist->cmdline = (grub_uint32_t) cmdline;
modlist->pad = 0;
mbi->mods_count = 1;
mbi->mods_addr = (grub_uint32_t) modlist;
mbi->flags |= MULTIBOOT_INFO_MODS;
}
fail:
if (file)
grub_file_close (file);
if (grub_errno != GRUB_ERR_NONE)
{
grub_free (module);
grub_free (cmdline);
}
}
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